WorldWideScience

Sample records for resistance-associated maize anionic

  1. A Genome-Wide Association Study Reveals Genes Associated with Fusarium Ear Rot Resistance in a Maize Core Diversity Panel

    Science.gov (United States)

    Zila, Charles T.; Samayoa, L. Fernando; Santiago, Rogelio; Butrón, Ana; Holland, James B.

    2013-01-01

    Fusarium ear rot is a common disease of maize that affects food and feed quality globally. Resistance to the disease is highly quantitative, and maize breeders have difficulty incorporating polygenic resistance alleles from unadapted donor sources into elite breeding populations without having a negative impact on agronomic performance. Identification of specific allele variants contributing to improved resistance may be useful to breeders by allowing selection of resistance alleles in coupling phase linkage with favorable agronomic characteristics. We report the results of a genome-wide association study to detect allele variants associated with increased resistance to Fusarium ear rot in a maize core diversity panel of 267 inbred lines evaluated in two sets of environments. We performed association tests with 47,445 single-nucleotide polymorphisms (SNPs) while controlling for background genomic relationships with a mixed model and identified three marker loci significantly associated with disease resistance in at least one subset of environments. Each associated SNP locus had relatively small additive effects on disease resistance (±1.1% on a 0–100% scale), but nevertheless were associated with 3 to 12% of the genotypic variation within or across environment subsets. Two of three identified SNPs colocalized with genes that have been implicated with programmed cell death. An analysis of associated allele frequencies within the major maize subpopulations revealed enrichment for resistance alleles in the tropical/subtropical and popcorn subpopulations compared with other temperate breeding pools. PMID:24048647

  2. Fitness costs associated with field-evolved resistance to Bt maize in Spodoptera frugiperda (Lepidoptera: Noctuidae).

    Science.gov (United States)

    Jakka, S R K; Knight, V R; Jurat-Fuentes, J L

    2014-02-01

    Increasing adoption of transgenic crops expressing cry toxin genes from Bacillus thuringiensis (Bt crops) represents an augmented risk for development of insect resistance. While fitness costs can greatly influence the rate of resistance evolution, most available data related to Bt resistance have been obtained from laboratory-selected insect strains. In this article, we test the existence of fitness costs associated with high levels of field-evolved resistance to Bt maize event TC1507 in a strain of Spodoptera frugiperda (JE Smith) originated from maize fields in Puerto Rico. Fitness costs in resistant S. frugiperda were evaluated by comparing biological performance to susceptible insects when reared on meridic diet, maize or soybean leaf tissue, or cotton reproductive tissues. Parameters monitored included larval survival, larval and pupal weights, developmental time (larval and pupal), adult longevity, reproductive traits (fecundity and fertility), and sex ratio. We found that all monitored parameters were influenced to a similar extent by the host, independently of susceptibility to Bt maize. The only parameter that significantly differed between strains for all hosts was a longer larval developmental period in resistant S. frugiperda, which resulted in emergence asynchrony between susceptible and resistant adults. To test the relevance of fitness costs in resistant S. frugiperda, we performed a selection experiment to monitor the stability of resistance in a heterogeneous strain through 12 generations of rearing on meridic diet. Our data demonstrate lack of fitness costs relevant to stability of field-evolved resistance to Bt maize and help explain reported stability of field-evolved resistance in Puerto Rican populations of S. frugiperda.

  3. Genome-Wide Association Mapping of and Aspergillus flavus Aflatoxin Accumulation Resistance in Maize

    Science.gov (United States)

    Marilyn L. Warburton; Juliet D. Tang; Gary L. Windham; Leigh K. Hawkins; Seth C. Murray; Wenwei Xu; Debbie Boykin; Andy Perkins; W. Paul Williams

    2015-01-01

    Contamination of maize (Zea mays L.) with aflatoxin, produced by the fungus Aspergillus flavus Link, has severe health and economic consequences. Efforts to reduce aflatoxin accumulation in maize have focused on identifying and selecting germplasm with natural host resistance factors, and several maize lines with significantly...

  4. genome-wide association and metabolic pathway analysis of corn earworm resistance in maize

    Science.gov (United States)

    Marilyn L. Warburton; Erika D. Womack; Juliet D. Tang; Adam Thrash; J. Spencer Smith; Wenwei Xu; Seth C. Murray; W. Paul Williams

    2018-01-01

    Maize (Zea mays mays L.) is a staple crop of economic, industrial, and food security importance. Damage to the growing ears by corn earworm [Helicoverpa zea (Boddie)] is a major economic burden and increases secondary fungal infections and mycotoxin levels. To identify biochemical pathways associated with native resistance mechanisms, a genome-wide...

  5. Field-Evolved Resistance to Bt Maize by Western Corn Rootworm

    Science.gov (United States)

    Gassmann, Aaron J.; Petzold-Maxwell, Jennifer L.; Keweshan, Ryan S.; Dunbar, Mike W.

    2011-01-01

    Background Crops engineered to produce insecticidal toxins derived from the bacterium Bacillus thuringiensis (Bt) are planted on millions of hectares annually, reducing the use of conventional insecticides and suppressing pests. However, the evolution of resistance could cut short these benefits. A primary pest targeted by Bt maize in the United States is the western corn rootworm Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae). Methodology/Principal Findings We report that fields identified by farmers as having severe rootworm feeding injury to Bt maize contained populations of western corn rootworm that displayed significantly higher survival on Cry3Bb1 maize in laboratory bioassays than did western corn rootworm from fields not associated with such feeding injury. In all cases, fields experiencing severe rootworm feeding contained Cry3Bb1 maize. Interviews with farmers indicated that Cry3Bb1 maize had been grown in those fields for at least three consecutive years. There was a significant positive correlation between the number of years Cry3Bb1 maize had been grown in a field and the survival of rootworm populations on Cry3Bb1 maize in bioassays. However, there was no significant correlation among populations for survival on Cry34/35Ab1 maize and Cry3Bb1 maize, suggesting a lack of cross resistance between these Bt toxins. Conclusions/Significance This is the first report of field-evolved resistance to a Bt toxin by the western corn rootworm and by any species of Coleoptera. Insufficient planting of refuges and non-recessive inheritance of resistance may have contributed to resistance. These results suggest that improvements in resistance management and a more integrated approach to the use of Bt crops may be necessary. PMID:21829470

  6. The Identification of Two Head Smut Resistance-Related QTL in Maize by the Joint Approach of Linkage Mapping and Association Analysis.

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    Yong-xiang Li

    Full Text Available Head smut, caused by the fungus Sphacelotheca reiliana (Kühn Clint, is a devastating threat to maize production. In this study, QTL mapping of head smut resistance was performed using a recombinant inbred line (RIL population from a cross between a resistant line "QI319" and a susceptible line "Huangzaosi" (HZS with a genetic map constructed from genotyping-by-sequencing (GBS data and composed of 1638 bin markers. Two head smut resistance QTL were identified, located on Chromosome 2 (q2.09HR and Chromosome 5 (q5.03HR, q2.09HR is co-localized with a previously reported QTL for head smut resistance, and the effect of q5.03HR has been validated in backcross populations. It was also observed that pyramiding the resistant alleles of both QTL enhanced the level of resistance to head smut. A genome-wide association study (GWAS using 277 diverse inbred lines was processed to validate the mapped QTL and to identify additional head smut resistance associations. A total of 58 associated SNPs were detected, which were distributed in 31 independent regions. SNPs with significant association to head smut resistance were detected within the q2.09HR and q5.03HR regions, confirming the linkage mapping results. It was also observed that both additive and epistastic effects determine the genetic architecture of head smut resistance in maize. As shown in this study, the combined strategy of linkage mapping and association analysis is a powerful approach in QTL dissection for disease resistance in maize.

  7. Identification of sources of resistance to anthracnose stalk rot in maize

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    Alessandro Nicoli

    Full Text Available ABSTRACT: Adoption of resistant cultivars is the primary measure used to control anthracnose stalk rot. The goal of this study was to identify maize-resistant genotypes to anthracnose stalk rot, which are similar to the hybrid 2B710. Experiments were performed at Embrapa Maize and Sorghum experimental fields in Brazil. The first experimental trial evaluated 234 maize lines as well as two commercials hybrids, BRS1010 (susceptible and 2B710 (resistant. Artificial inoculations were performed with a strain at the blister (R2 phase, and evaluation of disease severity was performed after 30 days. The second experimental trial evaluated 48 maize lines and hybrids, inoculated with two Colletotrichum graminicola strains. In the first trial, eight resistance groups were formed, and the last lines were more resistant, as was the hybrid 2B710, with values between 11.50% and 23.0% of severity. In the second trial, there was an interaction between the two factors, lines and isolates, and the lines often showed the same reaction features as those obtained in the first trial. However, the disease severity was higher for most lines, even when using other isolates. These lines with effective levels of resistance could be used in future studies of inheritance, in programs to develop hybrids, and to identify molecular markers associated with resistance to anthracnose stalk rot in maize.

  8. Maize ZmALMT2 is a root anion transporter that mediates constitutive root malate efflux.

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    Ligaba, Ayalew; Maron, Lyza; Shaff, Jon; Kochian, Leon; Piñeros, Miguel

    2012-07-01

    Root efflux of organic acid anions underlies a major mechanism of plant aluminium (Al) tolerance on acid soils. This efflux is mediated by transporters of the Al-activated malate transporter (ALMT) or the multi-drug and toxin extrusion (MATE) families. ZmALMT2 was previously suggested to be involved in Al tolerance based on joint association-linkage mapping for maize Al tolerance. In the current study, we functionally characterized ZmALMT2 by heterologously expressing it in Xenopus laevis oocytes and transgenic Arabidopsis. In oocytes, ZmALMT2 mediated an Al-independent electrogenic transport product of organic and inorganic anion efflux. Ectopic overexpression of ZmALMT2 in an Al-hypersensitive Arabidopsis KO/KD line lacking the Al tolerance genes, AtALMT1 and AtMATE, resulted in Al-independent constitutive root malate efflux which partially restored the Al tolerance phenotype. The lack of correlation between ZmALMT2 expression and Al tolerance (e.g., expression not localized to the root tip, not up-regulated by Al, and higher in sensitive versus tolerance maize lines) also led us to question ZmALMT2's role in Al tolerance. The functional properties of the ZmALMT2 transporter presented here, along with the gene expression data, suggest that ZmALMT2 is not involved in maize Al tolerance but, rather, may play a role in mineral nutrient acquisition and transport. Published 2011. This article is a U.S. Government work and is in the public domain in the USA.

  9. Molecular Basis of Resistance to Fusarium Ear Rot in Maize

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    Alessandra Lanubile

    2017-10-01

    Full Text Available The impact of climate change has been identified as an emerging issue for food security and safety, and the increased incidence of mycotoxin contamination in maize over the last two decades is considered a potential emerging hazard. Disease control by chemical and agronomic approaches is often ineffective and increases the cost of production; for this reason the exploitation of genetic resistance is the most sustainable method for reducing contamination. The review focuses on the significant advances that have been made in the development of transcriptomic, genetic and genomic information for maize, Fusarium verticillioides molds, and their interactions, over recent years. Findings from transcriptomic studies have been used to outline a specific model for the intracellular signaling cascade occurring in maize cells against F. verticillioides infection. Several recognition receptors, such as receptor-like kinases and R genes, are involved in pathogen perception, and trigger down-stream signaling networks mediated by mitogen-associated protein kinases. These signals could be orchestrated primarily by hormones, including salicylic acid, auxin, abscisic acid, ethylene, and jasmonic acid, in association with calcium signaling, targeting multiple transcription factors that in turn promote the down-stream activation of defensive response genes, such as those related to detoxification processes, phenylpropanoid, and oxylipin metabolic pathways. At the genetic and genomic levels, several quantitative trait loci (QTL and single-nucleotide polymorphism markers for resistance to Fusarium ear rot deriving from QTL mapping and genome-wide association studies are described, indicating the complexity of this polygenic trait. All these findings will contribute to identifying candidate genes for resistance and to applying genomic technologies for selecting resistant maize genotypes and speeding up a strategy of breeding to contrast disease, through plants

  10. Developing Inset Resistant Maize Varieties for Food Security in Kenya

    International Nuclear Information System (INIS)

    Mugo, S.

    2002-01-01

    The Insect Resistant Maize for Africa (IRMA) project aims at increasing maize production and food security through development and deployment of stem borer resistant maize germplasm developed using conventional and through biotechnology methods such as Bt maize. Bt maize offers farmers an effective and practical option for controlling stem borers. It was recognized that the development and routine use of Bt maize will require addressing relevant bio-safety, environmental, and community concerns and research and information gathering activities are in place to address these concerns and research and information gathering activities are in place to address these concerns. Suitable Bt gene have been acquired or synthesized and back-crossed into elite maize germplasm at CIMMYT-Mexico, and the effective Cry-proteins against the major maize stem borers in Kenya were identified to better target pests. Stem borer resistant maize germplasm is being developed through conventional breeding, using locally adapted and exotic germplasm. for safe and effective deployment of Bt maize,studies on its impacts on target and non-target arthropods as well as studies on the effects of Bt maize on key non-target arthropods as well as studies on gene flow are underway. Insect resistance management strategies are being developed through quantifying the effectiveness, ???. Socioeconomic impact studies are revealing factors in the society that may influence the adoption of Bt maize in Kenya. Also, baseline data, essential for the monitoring and evaluation of the Bt maize technology in Kenya, has been established. Technology transfer and capacity building, creating awareness and communications have received attention in the project. This paper describes the major research activities as they relate to development of the stem bore resistant maize germplasm

  11. Assessment of Inheritance and Fitness Costs Associated with Field-Evolved Resistance to Cry3Bb1 Maize by Western Corn Rootworm.

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    Paolino, Aubrey R; Gassmann, Aaron J

    2017-05-11

    The western corn rootworm, Diabrotica virgifera virgifera LeConte, is among the most serious insect pests of maize in North America. One strategy used to manage this pest is transgenic maize that produces one or more crystalline (Cry) toxins derived from the bacterium Bacillus thuringiensis (Bt). To delay Bt resistance by insect pests, refuges of non-Bt maize are grown in conjunction with Bt maize. Two factors influencing the success of the refuge strategy to delay resistance are the inheritance of resistance and fitness costs, with greater delays in resistance expected when inheritance of resistance is recessive and fitness costs are present. We measured inheritance and fitness costs of resistance for two strains of western corn rootworm with field-evolved resistance to Cry3Bb1 maize. Plant-based and diet-based bioassays revealed that the inheritance of resistance was non-recessive. In a greenhouse experiment, in which larvae were reared on whole maize plants in field soil, no fitness costs of resistance were detected. In a laboratory experiment, in which larvae experienced intraspecific and interspecific competition for food, a fitness cost of delayed larval development was identified, however, no other fitness costs were found. These findings of non-recessive inheritance of resistance and minimal fitness costs, highlight the potential for the rapid evolution of resistance to Cry3Bb1 maize by western corn rootworm, and may help to improve resistance management strategies for this pest.

  12. Assessment of Inheritance and Fitness Costs Associated with Field-Evolved Resistance to Cry3Bb1 Maize by Western Corn Rootworm

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    Aubrey R. Paolino

    2017-05-01

    Full Text Available The western corn rootworm, Diabrotica virgifera virgifera LeConte, is among the most serious insect pests of maize in North America. One strategy used to manage this pest is transgenic maize that produces one or more crystalline (Cry toxins derived from the bacterium Bacillus thuringiensis (Bt. To delay Bt resistance by insect pests, refuges of non-Bt maize are grown in conjunction with Bt maize. Two factors influencing the success of the refuge strategy to delay resistance are the inheritance of resistance and fitness costs, with greater delays in resistance expected when inheritance of resistance is recessive and fitness costs are present. We measured inheritance and fitness costs of resistance for two strains of western corn rootworm with field-evolved resistance to Cry3Bb1 maize. Plant-based and diet-based bioassays revealed that the inheritance of resistance was non-recessive. In a greenhouse experiment, in which larvae were reared on whole maize plants in field soil, no fitness costs of resistance were detected. In a laboratory experiment, in which larvae experienced intraspecific and interspecific competition for food, a fitness cost of delayed larval development was identified, however, no other fitness costs were found. These findings of non-recessive inheritance of resistance and minimal fitness costs, highlight the potential for the rapid evolution of resistance to Cry3Bb1 maize by western corn rootworm, and may help to improve resistance management strategies for this pest.

  13. Identification of resistance to Maize rayado fino virus in maize inbred lines

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    Maize rayado fino virus (MRFV) is one of the most important virus diseases of maize in America. Severe yield losses, ranging from 10 to 50% in landraces to nearly 100% in contemporary cultivars, have been reported. Resistance has been reported in populations, but few inbred lines have been identifie...

  14. The Mechanisms of Maize Resistance to Fusarium verticillioides by comprehensive analysis of RNA-seq Data

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    Yanping Wang

    2016-11-01

    Full Text Available Fusarium verticillioides is the most commonly reported fungal species responsible for ear rot of maize which substantially reduces grain yield. It also results in a substantial accumulation of mycotoxins that give rise to toxic response when ingested by animals and humans. For inefficient control by chemical and agronomic measures, it thus becomes more desirable to select more resistant varieties. However, the molecular mechanisms underlying the infection process remain poorly understood, which hampers the application of quantitative resistance in breeding programs. Here, we reveal the disease-resistance mechanism of the maize inbred line of BT-1 which displays high resistance to ear rot using RNA high throughput sequencing. By analyzing RNA-seq data from the BT-1 kernels before and after F. verticillioides inoculation, we found that transcript levels of genes associated with key pathways are dramatically changed compared with the control treatment. Differential gene expression in ear rot resistant and susceptible maize was confirmed by RNA microarray and qRT-PCR analyses. Further investigation suggests that the small heat shock protein family, some secondary metabolites, and the signaling pathways of abscisic acid (ABA, jasmonic acid (JA or salicylic acids (SA may be involved in the pathogen-associated molecular pattern-triggered immunity against F. verticillioides. These data will not only provide new insights into the molecular resistant mechanisms against fungi invading, but may also result in the identification of key molecular factors associated with ear rot resistance in maize.

  15. Resistance to dual-gene Bt maize in Spodoptera frugiperda: selection, inheritance, and cross-resistance to other transgenic events.

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    Santos-Amaya, Oscar F; Rodrigues, João V C; Souza, Thadeu C; Tavares, Clébson S; Campos, Silverio O; Guedes, Raul N C; Pereira, Eliseu J G

    2015-12-17

    Transgenic crop "pyramids" producing two or more Bacillus thuringiensis (Bt) toxins active against the same pest are used to delay evolution of resistance in insect pest populations. Laboratory and greenhouse experiments were performed with fall armyworm, Spodoptera frugiperda, to characterize resistance to Bt maize producing Cry1A.105 and Cry2Ab and test some assumptions of the "pyramid" resistance management strategy. Selection of a field-derived strain of S. frugiperda already resistant to Cry1F maize with Cry1A.105 + Cry2Ab maize for ten generations produced resistance that allowed the larvae to colonize and complete the life cycle on these Bt maize plants. Greenhouse experiments revealed that the resistance was completely recessive (Dx = 0), incomplete, autosomal, and without maternal effects or cross-resistance to the Vip3Aa20 toxin produced in other Bt maize events. This profile of resistance supports some of the assumptions of the pyramid strategy for resistance management. However, laboratory experiments with purified Bt toxin and plant leaf tissue showed that resistance to Cry1A.105 + Cry2Ab2 maize further increased resistance to Cry1Fa, which indicates that populations of fall armyworm have high potential for developing resistance to some currently available pyramided maize used against this pest, especially where resistance to Cry1Fa was reported in the field.

  16. Validation of candidate genes putatively associated with resistance to SCMV and MDMV in maize (Zea mays L.) by expression profiling

    DEFF Research Database (Denmark)

    Uzarowska, Anna; Dionisio, Giuseppe; Sarholz, Barbara

    2009-01-01

    Background The potyviruses sugarcane mosaic virus (SCMV) and maize dwarf mosaic virus (MDMV) are major pathogens of maize worldwide. Two loci, Scmv1 and Scmv2, have ealier been shown to confer complete resistance to SCMV. Custom-made microarrays containing previously identified SCMV resistance...... the effectiveness and reliability of the combination of different expression profiling approaches for the identification and validation of candidate genes. Genes identified in this study represent possible future targets for manipulation of SCMV resistance in maize....

  17. A maize resistance gene functions against bacterial streak disease in rice.

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    Zhao, Bingyu; Lin, Xinghua; Poland, Jesse; Trick, Harold; Leach, Jan; Hulbert, Scot

    2005-10-25

    Although cereal crops all belong to the grass family (Poacea), most of their diseases are specific to a particular species. Thus, a given cereal species is typically resistant to diseases of other grasses, and this nonhost resistance is generally stable. To determine the feasibility of transferring nonhost resistance genes (R genes) between distantly related grasses to control specific diseases, we identified a maize R gene that recognizes a rice pathogen, Xanthomonas oryzae pv. oryzicola, which causes bacterial streak disease. Bacterial streak is an important disease of rice in Asia, and no simply inherited sources of resistance have been identified in rice. Although X. o. pv. oryzicola does not cause disease on maize, we identified a maize gene, Rxo1, that conditions a resistance reaction to a diverse collection of pathogen strains. Surprisingly, Rxo1 also controls resistance to the unrelated pathogen Burkholderia andropogonis, which causes bacterial stripe of sorghum and maize. The same gene thus controls resistance reactions to both pathogens and nonpathogens of maize. Rxo1 has a nucleotide-binding site-leucine-rich repeat structure, similar to many previously identified R genes. Most importantly, Rxo1 functions after transfer as a transgene to rice, demonstrating the feasibility of nonhost R gene transfer between cereals and providing a valuable tool for controlling bacterial streak disease.

  18. Genetics of resistance to stored grain weevil (Sitophilus oryzae L. in maize

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    Rajkumar Zunjare

    2015-12-01

    Full Text Available Stored grain weevil (Sitophilus oryzae has emerged as important storage grain pest of maize, causing substantial economic losses. Owing to high costs and environmental hazards of pesticides, host plant resistance holds promise for effective control of weevils. In the present study, a set of experimental maize hybrids generated using line × tester mating design were evaluated against S. oryzae. Significant variation for grain weight loss (GWL (6.0–49.1%, number of insect progeny emerged (NIP (17.8–203.3, grain hardness (GH (263.1–495.4 N, and pericarp thickness (PT (60.3–161.0 μm was observed. Strong positive association was observed between GWL and NIP. GH and PT did not show any correlation with GWL and NIP. Additive and non-additive gene actions were important for both GWL and NIP. Promising inbreds and experimental crosses identified can be effectively utilized in the resistance breeding programme. In majority of promising crosses having desirable SCA effects, one of the parents had desirable GCA effects, indicating that selection of inbred parents based on per se performance for generating resistant crosses may be possible. The commercial hybrid checks were highly susceptible compared to experimental hybrids. The inbreds and experimental hybrids identified hold promise in developing weevil resistant maize cultivars offering sustainable solution to management of weevils in maize.

  19. Integrated database for identifying candidate genes for Aspergillus flavus resistance in maize.

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    Kelley, Rowena Y; Gresham, Cathy; Harper, Jonathan; Bridges, Susan M; Warburton, Marilyn L; Hawkins, Leigh K; Pechanova, Olga; Peethambaran, Bela; Pechan, Tibor; Luthe, Dawn S; Mylroie, J E; Ankala, Arunkanth; Ozkan, Seval; Henry, W B; Williams, W P

    2010-10-07

    Aspergillus flavus Link:Fr, an opportunistic fungus that produces aflatoxin, is pathogenic to maize and other oilseed crops. Aflatoxin is a potent carcinogen, and its presence markedly reduces the value of grain. Understanding and enhancing host resistance to A. flavus infection and/or subsequent aflatoxin accumulation is generally considered an efficient means of reducing grain losses to aflatoxin. Different proteomic, genomic and genetic studies of maize (Zea mays L.) have generated large data sets with the goal of identifying genes responsible for conferring resistance to A. flavus, or aflatoxin. In order to maximize the usage of different data sets in new studies, including association mapping, we have constructed a relational database with web interface integrating the results of gene expression, proteomic (both gel-based and shotgun), Quantitative Trait Loci (QTL) genetic mapping studies, and sequence data from the literature to facilitate selection of candidate genes for continued investigation. The Corn Fungal Resistance Associated Sequences Database (CFRAS-DB) (http://agbase.msstate.edu/) was created with the main goal of identifying genes important to aflatoxin resistance. CFRAS-DB is implemented using MySQL as the relational database management system running on a Linux server, using an Apache web server, and Perl CGI scripts as the web interface. The database and the associated web-based interface allow researchers to examine many lines of evidence (e.g. microarray, proteomics, QTL studies, SNP data) to assess the potential role of a gene or group of genes in the response of different maize lines to A. flavus infection and subsequent production of aflatoxin by the fungus. CFRAS-DB provides the first opportunity to integrate data pertaining to the problem of A. flavus and aflatoxin resistance in maize in one resource and to support queries across different datasets. The web-based interface gives researchers different query options for mining the database

  20. Differential resistance reaction of maize genotypes to maize stem borer (Chilo partellus Swinhoe at Chitwan, Nepal

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    Ghanashyam Bhandari

    2016-12-01

    Full Text Available Maize stem borer (MSB, Chilo partellus Swinhoe, Lepidoptera: Pyralidae is one of the most important insect pest of maize in Nepal. Host plant resistance is the cost-effective, ecologically sound and stable approach to reduce damage by stem borers. Forty four maize genotypes were screened for resistance to maize stem borer at the research field of National Maize Research Program, Rampur during spring seasons (March to June of two consecutive years 2013 and 2014. The maize genotypes were evaluated in randomized complete block design with three replications and data were collected on foliar damage rating, tunnel length and number of exit holes made by the borer. The foliar damage and tunnel length damage were significant for genotypes for both the years. The exit holes were not significant in 2013 but significant in 2014 ranging from 2-6 scale. The foliar rating ranged from 2 to 5.5 in 2013 and 1.1 to 4.5 in 2014 on a 1-9 rating scale. The highly resistant genotypes (10 cm scale. The least susceptible genotypes (<5 cm were RampurSO3F8, RampurSO3FQ02 and RampurS10F18. The genotypes having least exit holes (2.0 in 2014 were RampurSO3F8, RampurSO3FQ02, RampurS10F18. Thus less damage parameters were observed in R-POP-2, RML-5/RML-8, RampurSO3F8, RampurSO3FQ02 and RampurS10F18 and therefore they can be used as parents or as sources of resistance in breeding program.

  1. Genome Wide Association Study for Drought, Aflatoxin Resistance, and Important Agronomic Traits of Maize Hybrids in the Sub-Tropics

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    Farfan, Ivan D. Barrero; De La Fuente, Gerald N.; Murray, Seth C.; Isakeit, Thomas; Huang, Pei-Cheng; Warburton, Marilyn; Williams, Paul; Windham, Gary L.; Kolomiets, Mike

    2015-01-01

    The primary maize (Zea mays L.) production areas are in temperate regions throughout the world and this is where most maize breeding is focused. Important but lower yielding maize growing regions such as the sub-tropics experience unique challenges, the greatest of which are drought stress and aflatoxin contamination. Here we used a diversity panel consisting of 346 maize inbred lines originating in temperate, sub-tropical and tropical areas testcrossed to stiff-stalk line Tx714 to investigate these traits. Testcross hybrids were evaluated under irrigated and non-irrigated trials for yield, plant height, ear height, days to anthesis, days to silking and other agronomic traits. Irrigated trials were also inoculated with Aspergillus flavus and evaluated for aflatoxin content. Diverse maize testcrosses out-yielded commercial checks in most trials, which indicated the potential for genetic diversity to improve sub-tropical breeding programs. To identify genomic regions associated with yield, aflatoxin resistance and other important agronomic traits, a genome wide association analysis was performed. Using 60,000 SNPs, this study found 10 quantitative trait variants for grain yield, plant and ear height, and flowering time after stringent multiple test corrections, and after fitting different models. Three of these variants explained 5–10% of the variation in grain yield under both water conditions. Multiple identified SNPs co-localized with previously reported QTL, which narrows the possible location of causal polymorphisms. Novel significant SNPs were also identified. This study demonstrated the potential to use genome wide association studies to identify major variants of quantitative and complex traits such as yield under drought that are still segregating between elite inbred lines. PMID:25714370

  2. RELATIONS AMONG WESTERN CORN ROOTWORM RESISTANCE TRAITS AND ELEMENTS CONCENTRATION IN MAIZE GERMPLASM ROOTS

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    Andrija Brkić

    2015-06-01

    Full Text Available Western corn rootworm – WCR (Diabrotica virgifera virgifera LeConte is an important maize pest in Croatia. Using native resistance of maize germplasm could reduce chemical treatments and other costs in maize production. Objectives of this study were: i to assess variability of WCR resistance traits (root injury, regrowth and size and concentrations of nine elements in roots of 128 maize genotypes, and ii to determine correlations among the traits and ion concentrations. Results revealed high variability of maize genotypes for both WCR resistance traits and ion concentrations. Significant moderate negative correlations (>-0.4 were detected between root injury and boron as well as between root regrowth and iron, manganese and zinc concentrations in root. Consequently, ion concentration in maize roots might have an impact on WCR resistance research.

  3. A gene encoding maize caffeoyl-CoA O-methyltransferase confers quantitative resistance to multiple pathogens.

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    Yang, Qin; He, Yijian; Kabahuma, Mercy; Chaya, Timothy; Kelly, Amy; Borrego, Eli; Bian, Yang; El Kasmi, Farid; Yang, Li; Teixeira, Paulo; Kolkman, Judith; Nelson, Rebecca; Kolomiets, Michael; L Dangl, Jeffery; Wisser, Randall; Caplan, Jeffrey; Li, Xu; Lauter, Nick; Balint-Kurti, Peter

    2017-09-01

    Alleles that confer multiple disease resistance (MDR) are valuable in crop improvement, although the molecular mechanisms underlying their functions remain largely unknown. A quantitative trait locus, qMdr 9.02 , associated with resistance to three important foliar maize diseases-southern leaf blight, gray leaf spot and northern leaf blight-has been identified on maize chromosome 9. Through fine-mapping, association analysis, expression analysis, insertional mutagenesis and transgenic validation, we demonstrate that ZmCCoAOMT2, which encodes a caffeoyl-CoA O-methyltransferase associated with the phenylpropanoid pathway and lignin production, is the gene within qMdr 9.02 conferring quantitative resistance to both southern leaf blight and gray leaf spot. We suggest that resistance might be caused by allelic variation at the level of both gene expression and amino acid sequence, thus resulting in differences in levels of lignin and other metabolites of the phenylpropanoid pathway and regulation of programmed cell death.

  4. Cry1F resistance in fall armyworm Spodoptera frugiperda: single gene versus pyramided Bt maize.

    Science.gov (United States)

    Huang, Fangneng; Qureshi, Jawwad A; Meagher, Robert L; Reisig, Dominic D; Head, Graham P; Andow, David A; Ni, Xinzi; Kerns, David; Buntin, G David; Niu, Ying; Yang, Fei; Dangal, Vikash

    2014-01-01

    Evolution of insect resistance to transgenic crops containing Bacillus thuringiensis (Bt) genes is a serious threat to the sustainability of this technology. However, field resistance related to the reduced efficacy of Bt maize has not been documented in any lepidopteran pest in the mainland U.S. after 18 years of intensive Bt maize planting. Here we report compelling evidence of field resistance in the fall armyworm, Spodoptera frugiperda (J.E. Smith), to Cry1F maize (TC 3507) in the southeastern region of the U.S. An F2 screen showed a surprisingly high (0.293) Cry1F resistance allele frequency in a population collected in 2011 from non-Bt maize in south Florida. Field populations from non-Bt maize in 2012-2013 exhibited 18.8-fold to >85.4-fold resistance to purified Cry1F protein and those collected from unexpectedly damaged Bt maize plants at several locations in Florida and North Carolina had >85.4-fold resistance. In addition, reduced efficacy and control failure of Cry1F maize against natural populations of S. frugiperda were documented in field trials using Cry1F-based and pyramided Bt maize products in south Florida. The Cry1F-resistant S. frugiperda also showed a low level of cross-resistance to Cry1A.105 and related maize products, but not to Cry2Ab2 or Vip3A. The occurrence of Cry1F resistance in the U.S. mainland populations of S. frugiperda likely represents migration of insects from Puerto Rico, indicating the great challenges faced in achieving effective resistance management for long-distance migratory pests like S. frugiperda.

  5. A Maize Inbred Exhibits Resistance Against Western Corn Rootwoorm, Diabrotica virgifera virgifera.

    Science.gov (United States)

    Castano-Duque, Lina; Loades, Kenneth W; Tooker, John F; Brown, Kathleen M; Paul Williams, W; Luthe, Dawn S

    2017-12-01

    Insect resistance against root herbivores like the western corn rootworm (WCR, Diabrotica virgifera virgifera) is not well understood in non-transgenic maize. We studied the responses of two American maize inbreds, Mp708 and Tx601, to WCR infestation using biomechanical, molecular, biochemical analyses, and laser ablation tomography. Previous studies performed on several inbreds indicated that these two maize genotypes differed in resistance to pests including fall armyworm (Spodoptera frugiperda) and WCR. Our data confirmed that Mp708 shows resistance against WCR, and demonstrates that the resistance mechanism is based in a multi-trait phenotype that includes increased resistance to cutting in nodal roots, stable root growth during insect infestation, constitutive and induced expression of known herbivore-defense genes, including ribosomal inhibitor protein 2 (rip2), terpene synthase 23 (tps23) and maize insect resistance cysteine protease-1 (mir1), as well high constitutive levels of jasmonic acid and production of (E)-β-caryophyllene. In contrast, Tx601 is susceptible to WCR. These findings will facilitate the use of Mp708 as a model to explore the wide variety of mechanisms and traits involved in plant defense responses and resistance to herbivory by insects with several different feeding habits.

  6. Ethylene Contributes to maize insect resistance1-Mediated Maize Defense against the Phloem Sap-Sucking Corn Leaf Aphid1[OPEN

    Science.gov (United States)

    Louis, Joe; Basu, Saumik; Varsani, Suresh; Castano-Duque, Lina; Jiang, Victoria; Williams, W. Paul; Felton, Gary W.; Luthe, Dawn S.

    2015-01-01

    Signaling networks among multiple phytohormones fine-tune plant defense responses to insect herbivore attack. Previously, it was reported that the synergistic combination of ethylene (ET) and jasmonic acid (JA) was required for accumulation of the maize insect resistance1 (mir1) gene product, a cysteine (Cys) proteinase that is a key defensive protein against chewing insect pests in maize (Zea mays). However, this study suggests that mir1-mediated resistance to corn leaf aphid (CLA; Rhopalosiphum maidis), a phloem sap-sucking insect pest, is independent of JA but regulated by the ET-signaling pathway. Feeding by CLA triggers the rapid accumulation of mir1 transcripts in the resistant maize genotype, Mp708. Furthermore, Mp708 provided elevated levels of antibiosis (limits aphid population)- and antixenosis (deters aphid settling)-mediated resistance to CLA compared with B73 and Tx601 maize susceptible inbred lines. Synthetic diet aphid feeding trial bioassays with recombinant Mir1-Cys Protease demonstrates that Mir1-Cys Protease provides direct toxicity to CLA. Furthermore, foliar feeding by CLA rapidly sends defensive signal(s) to the roots that trigger belowground accumulation of the mir1, signifying a potential role of long-distance signaling in maize defense against the phloem-feeding insects. Collectively, our data indicate that ET-regulated mir1 transcript accumulation, uncoupled from JA, contributed to heightened resistance to CLA in maize. In addition, our results underscore the significance of ET acting as a central node in regulating mir1 expression to different feeding guilds of insect herbivores. PMID:26253737

  7. Effective dominance of resistance of Spodoptera frugiperda to Bt maize and cotton varieties: implications for resistance management

    Science.gov (United States)

    Horikoshi, Renato J.; Bernardi, Daniel; Bernardi, Oderlei; Malaquias, José B.; Okuma, Daniela M.; Miraldo, Leonardo L.; Amaral, Fernando S. De A. E.; Omoto, Celso

    2016-10-01

    The resistance of fall armyworm (FAW), Spodoptera frugiperda, has been characterized to some Cry and Vip3A proteins of Bacillus thuringiensis (Bt) expressed in transgenic maize in Brazil. Here we evaluated the effective dominance of resistance based on the survival of neonates from selected Bt-resistant, heterozygous, and susceptible (Sus) strains of FAW on different Bt maize and cotton varieties. High survival of strains resistant to the Cry1F (HX-R), Cry1A.105/Cry2Ab (VT-R) and Cry1A.105/Cry2Ab/Cry1F (PW-R) proteins was detected on Herculex, YieldGard VT PRO and PowerCore maize. Our Vip3A-resistant strain (Vip-R) exhibited high survival on Herculex, Agrisure Viptera and Agrisure Viptera 3 maize. However, the heterozygous from HX-R × Sus, VT-R × Sus, PW-R × Sus and Vip-R × Sus had complete mortality on YieldGard VT PRO, PowerCore, Agrisure Viptera, and Agrisure Viptera 3, whereas the HX-R × Sus and Vip-R × Sus strains survived on Herculex maize. On Bt cotton, the HX-R, VT-R and PW-R strains exhibited high survival on Bollgard II. All resistant strains survived on WideStrike, but only PW-R and Vip-R × Sus survived on TwinLink. Our study provides useful data to aid in the understanding of the effectiveness of the refuge strategy for Insect Resistance Management of Bt plants.

  8. Sixteen Years of Bt Maize in the EU Hotspot: Why Has Resistance Not Evolved?

    Directory of Open Access Journals (Sweden)

    Pedro Castañera

    Full Text Available The majority of Bt maize production in the European Union (EU is concentrated in northeast Spain, which is Europe's only hotspot where resistance might evolve, and the main target pest, Sesamia nonagrioides, has been exposed to Cry1Ab maize continuously since 1998. The cropping system in northeast Spain has some similar characteristics to those that probably led to rapid resistance failures in two other target noctuid maize pests. These include repeated cultivation of Bt maize in the same fields, low use of refuges, recurring exposure of larvae to non-high dose concentrations of Cry1Ab toxin during the first years of cultivation, low migratory potential, and production concentrated in an irrigated region with few alternative hosts. Available data reveal no evidence of resistance in S. nonagrioides after 16 years of use. We explore the possible reasons for this resistance management success using evolutionary models to consider factors expected to accelerate resistance, and those expected to delay resistance. Low initial adoption rates and the EU policy decision to replace Event 176 with MON 810 Bt maize were key to delaying resistance evolution. Model results suggest that if refuge compliance continues at the present 90%, Bt maize might be used sustainably in northeast Spain for at least 20 more years before resistance might occur. However, obtaining good estimates of the present R allele frequency and level of local assortative mating are crucial to reduce uncertainty about the future success of resistance management.

  9. A Public Platform for the Verification of the Phenotypic Effect of Candidate Genes for Resistance to Aflatoxin Accumulation and Aspergillus flavus Infection in Maize

    Directory of Open Access Journals (Sweden)

    Xueyan Shan

    2011-06-01

    Full Text Available A public candidate gene testing pipeline for resistance to aflatoxin accumulation or Aspergillus flavus infection in maize is presented here. The pipeline consists of steps for identifying, testing, and verifying the association of selected maize gene sequences with resistance under field conditions. Resources include a database of genetic and protein sequences associated with the reduction in aflatoxin contamination from previous studies; eight diverse inbred maize lines for polymorphism identification within any maize gene sequence; four Quantitative Trait Loci (QTL mapping populations and one association mapping panel, all phenotyped for aflatoxin accumulation resistance and associated phenotypes; and capacity for Insertion/Deletion (InDel and SNP genotyping in the population(s for mapping. To date, ten genes have been identified as possible candidate genes and put through the candidate gene testing pipeline, and results are presented here to demonstrate the utility of the pipeline.

  10. Confirmation and Fine Mapping of a Major QTL for Aflatoxin Resistance in Maize Using a Combination of Linkage and Association Mapping

    Directory of Open Access Journals (Sweden)

    Yu Zhang

    2016-09-01

    Full Text Available Maize grain contamination with aflatoxin from Aspergillus flavus (A. flavus is a serious health hazard to animals and humans. To map the quantitative trait loci (QTLs associated with resistance to A. flavus, we employed a powerful approach that differs from previous methods in one important way: it combines the advantages of the genome-wide association analysis (GWAS and traditional linkage mapping analysis. Linkage mapping was performed using 228 recombinant inbred lines (RILs, and a highly significant QTL that affected aflatoxin accumulation, qAA8, was mapped. This QTL spanned approximately 7 centi-Morgan (cM on chromosome 8. The confidence interval was too large for positional cloning of the causal gene. To refine this QTL, GWAS was performed with 558,629 single nucleotide polymorphisms (SNPs in an association population comprising 437 maize inbred lines. Twenty-five significantly associated SNPs were identified, most of which co-localised with qAA8 and explained 6.7% to 26.8% of the phenotypic variation observed. Based on the rapid linkage disequilibrium (LD and the high density of SNPs in the association population, qAA8 was further localised to a smaller genomic region of approximately 1500 bp. A high-resolution map of the qAA8 region will be useful towards a marker-assisted selection (MAS of A. flavus resistance and a characterisation of the causal gene.

  11. Evaluation of fall armyworm resistance in maize germplasm lines using visual leaf injury rating and predator survey

    Science.gov (United States)

    After examining ear-colonizing pest resistance, 20 maize lines from the USDA-ARS germplasm enhancement of Maize (GEM) Program were evaluated for whorl-feeding fall armyworm (FAW) (Spodoptera frugiperda) resistance using four maize inbred lines as the resistant and susceptible controls. Both FAW inju...

  12. Arthropods dataset from different genetically modified maize events and associated controls

    Science.gov (United States)

    Pálinkás, Zoltán; Zalai, Mihály; Szénási, Ágnes; Dorner, Zita; Kiss, József; North, Samuel; Woodward, Guy; Balog, Adalbert

    2018-02-01

    Arthropods from four genetically modified (GM) maize hybrids (coleopteran resistant, coleopteran and lepidopteran resistant, lepidopteran resistant+herbicide tolerant and coleopteran resistant and herbicide tolerant) and non-GM varieties were sampled during a two-year field assessment. A total number of 363 555 arthropod individuals were collected. This represents the most comprehensive arthropod dataset from GM maize, and together with weed data, is reasonable to determine functional groups of arthropods and interactions between species. Trophic groups identified from both phytophagous and predatory arthropods were previously considered non-target organisms on which possible detrimental effects of Bacillus thuringiensis (Bt) toxins may have been directly (phytophagous species) or indirectly (predators) detected. The high number of individuals and species and their dynamics through the maize growing season can predict that interactions are highly correlational, and can thus be considered a useful tool to assess potential deleterious effects of Bt toxins on non-target organisms, serving to develop biosafety risk hypotheses for invertebrates exposed to GM maize plants.

  13. The platelet-activating factor acetylhydrolase gene derived from Trichoderma harzianum induces maize resistance to Curvularia lunata through the jasmonic acid signaling pathway.

    Science.gov (United States)

    Yu, Chuanjin; Fan, Lili; Gao, Jinxin; Wang, Meng; Wu, Qiong; Tang, Jun; Li, Yaqian; Chen, Jie

    2015-01-01

    Platelet-activating factor acetylhydrolase (PAF-AH) derived from Trichoderma harzianum was upregulated by the interaction of T. harzianum with maize roots or the foliar pathogen Curvularia lunata. PAF-AH was associated with chitinase and cellulase expressions, but especially with chitinase, because its activity in the KO40 transformant (PAF-AH disruption transformant) was lower, compared with the wild-type strain T28. The result demonstrated that the colonization of maize roots by T. harzianum induced systemic protection of leaves inoculated with C. lunata. Such protection was associated with the expression of inducible jasmonic acid pathway-related genes. Moreover, the data from liquid chromatography-mass spectrometry confirmed that the concentration of jasmonic acid in maize leaves was associated with the expression level of defense-related genes, suggesting that PAF-AH induced resistance to the foliar pathogen. Our findings showed that PAF-AH had an important function in inducing systemic resistance to maize leaf spot pathogen.

  14. Survey of Candidate Genes for Maize Resistance to Infection by Aspergillus flavus and/or Aflatoxin Contamination

    Science.gov (United States)

    Hawkins, Leigh K.; Tang, Juliet D.; Tomashek, John; Alves Oliveira, Dafne; Ogunola, Oluwaseun F.; Smith, J. Spencer; Williams, W. Paul

    2018-01-01

    Many projects have identified candidate genes for resistance to aflatoxin accumulation or Aspergillus flavus infection and growth in maize using genetic mapping, genomics, transcriptomics and/or proteomics studies. However, only a small percentage of these candidates have been validated in field conditions, and their relative contribution to resistance, if any, is unknown. This study presents a consolidated list of candidate genes identified in past studies or in-house studies, with descriptive data including genetic location, gene annotation, known protein identifiers, and associated pathway information, if known. A candidate gene pipeline to test the phenotypic effect of any maize DNA sequence on aflatoxin accumulation resistance was used in this study to determine any measurable effect on polymorphisms within or linked to the candidate gene sequences, and the results are published here. PMID:29385107

  15. Survey of Candidate Genes for Maize Resistance to Infection by Aspergillus flavus and/or Aflatoxin Contamination

    Directory of Open Access Journals (Sweden)

    Leigh K. Hawkins

    2018-01-01

    Full Text Available Many projects have identified candidate genes for resistance to aflatoxin accumulation or Aspergillus flavus infection and growth in maize using genetic mapping, genomics, transcriptomics and/or proteomics studies. However, only a small percentage of these candidates have been validated in field conditions, and their relative contribution to resistance, if any, is unknown. This study presents a consolidated list of candidate genes identified in past studies or in-house studies, with descriptive data including genetic location, gene annotation, known protein identifiers, and associated pathway information, if known. A candidate gene pipeline to test the phenotypic effect of any maize DNA sequence on aflatoxin accumulation resistance was used in this study to determine any measurable effect on polymorphisms within or linked to the candidate gene sequences, and the results are published here.

  16. Genotypic variation for maize weevil resistance in eastern and ...

    African Journals Online (AJOL)

    ACSS

    Uganda Journal of Agricultural Sciences by National Agricultural Research Organisation ... damage, median development period, Dobie's index of susceptibility, and ... resistance and grain yield, suggesting that breeding for maize weevil ...

  17. Field-evolved resistance to Cry1Ab maize by Spodoptera frugiperda in Brazil.

    Science.gov (United States)

    Omoto, Celso; Bernardi, Oderlei; Salmeron, Eloisa; Sorgatto, Rodrigo J; Dourado, Patrick M; Crivellari, Augusto; Carvalho, Renato A; Willse, Alan; Martinelli, Samuel; Head, Graham P

    2016-09-01

    The first Bt maize in Brazil was launched in 2008 and contained the MON 810 event, which expresses Cry1Ab protein. Although the Cry1Ab dose in MON 810 is not high against fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith), MON 810 provided commercial levels of control. To support insect resistance management in Brazil, the baseline and ongoing susceptibility of FAW was examined using protein bioassays, and the level of control and life history parameters of FAW were evaluated on MON 810 maize. Baseline diet overlay assays with Cry1Ab (16 µg cm(-2) ) caused 76.3% mortality to field FAW populations sampled in 2009. Moderate mortality (48.8%) and significant growth inhibition (88.4%) were verified in leaf-disc bioassays. In greenhouse trials, MON 810 had significantly less damage than non-Bt maize. The surviving FAW larvae on MON 810 (22.4%) had a 5.5 day increase in life cycle time and a 24% reduction in population growth rate. Resistance monitoring (2010-2015) showed a significant reduction in Cry1Ab susceptibility of FAW over time. Additionally, a significant reduction in the field efficacy of MON 810 maize against FAW was observed in different regions from crop season 2009 to 2013. The decrease in susceptibility to Cry1Ab was expected, but the specific contributions to this resistance by MON 810 maize cannot be distinguished from cross-resistance to Cry1Ab caused by exposure to Cry1F maize. Technologies combining multiple novel insecticidal traits with no cross-resistance to the current Cry1 proteins and high activity against the same target pests should be pursued in Brazil and similar environments. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

  18. Maize germplasm of eastern Croatia with native resistance to western corn rootworm (Diabrotica virgifera virgifera LeConte

    Directory of Open Access Journals (Sweden)

    Brkić Andrija

    2017-01-01

    Full Text Available The western corn rootworm (Diabrotica virgifera virgifera LeConte; WCR is a serious maize pest in Croatia. The species was first registered in Europe in the early 1990s and since then became one of the most dangerous maize pests, especially in parts of Central and Southeast Europe. Larvae that feed on the maize roots cause the most serious damages in maize fields. Management of this pest is difficult and expensive, with possible serious impact on the environment. Native (or host-plant resistance of maize against WCR could provide new economically and ecologically sustainable options in WCR management. Main goal of this study was to assess the variability of maize germplasm, correlations among resistance traits, and detect potential sources of resistance that could be used in breeding programs in order to develop hybrids with higher level of resistance against WCR. To our knowledge, the first native resistant hybrid is yet to be registered. Results showed great variability of estimated germplasm. Effect of the genotype was significant in all environments, as well as many interactions between genotype and the environment. Significant interactions emphasize the importance of the environment in WCR native resistance research. Significant positive correlations among all traits were detected. Several inbred lines were selected as a potentially useful germplasm for resistance breeding programs.

  19. Cross-Resistance between Cry1 Proteins in Fall Armyworm (Spodoptera frugiperda) May Affect the Durability of Current Pyramided Bt Maize Hybrids in Brazil.

    Science.gov (United States)

    Bernardi, Daniel; Salmeron, Eloisa; Horikoshi, Renato Jun; Bernardi, Oderlei; Dourado, Patrick Marques; Carvalho, Renato Assis; Martinelli, Samuel; Head, Graham P; Omoto, Celso

    2015-01-01

    Genetically modified plants expressing insecticidal proteins from Bacillus thuringiensis (Bt) offer valuable options for managing insect pests with considerable environmental and economic benefits. Despite the benefits provided by Bt crops, the continuous expression of these insecticidal proteins imposes strong selection for resistance in target pest populations. Bt maize (Zea mays) hybrids have been successful in controlling fall armyworm (Spodoptera frugiperda), the main maize pest in Brazil since 2008; however, field-evolved resistance to the protein Cry1F has recently been reported. Therefore it is important to assess the possibility of cross-resistance between Cry1F and other Cry proteins expressed in Bt maize hybrids. In this study, an F2 screen followed by subsequent selection on MON 89034 maize was used to select an S. frugiperda strain (RR) able to survive on the Bt maize event MON 89034, which expresses the Cry1A.105 and Cry2Ab2 proteins. Field-collected insects from maize expressing the Cry1F protein (event TC1507) represented most of the positive (resistance allele-containing) (iso)families found. The RR strain showed high levels of resistance to Cry1F, which apparently also conferred high levels of cross resistance to Cry1A.105 and Cry1Ab, but had only low-level (10-fold) resistance to Cry2Ab2. Life history studies to investigate fitness costs associated with the resistance in RR strain revealed only small reductions in reproductive rate when compared to susceptible and heterozygous strains, but the RR strain produced 32.2% and 28.4% fewer females from each female relative to the SS and RS (pooled) strains, respectively. Consistent with the lack of significant resistance to Cry2Ab2, MON 89034 maize in combination with appropriate management practices continues to provide effective control of S. frugiperda in Brazil. Nevertheless, the occurrence of Cry1F resistance in S. frugiperda across Brazil, and the cross-resistance to Cry1Ab and Cry1A.105

  20. RESOURCE ALLOCATION IN A MAIZE BREEDING PROGRAM FOR NATIVE RESISTANCE TO WESTERN CORN ROOTWORM

    Directory of Open Access Journals (Sweden)

    Ivan Brkić

    2012-06-01

    Full Text Available The objective of this study was to determine the optimum allocation of the number of plants sampled per plot and number of locations and years required for screening maize genotypes for reduced root damage caused by western corn rootworm (WCR larvae, major pest of maize in Croatia, Europe and in the USA. Field trials were conducted on two locations Eastern Croatia, a major maize production area with natural WCR occurrence under continuous maize growing conditions. The trials were set as an incomplete lattice block design in two replications in 2007, 2008 and 2009 including 128 genotypes from various maize gene-pools. Our results suggest that the effect of year and respective interactions including year were the most important factors in maize breeding programs for native resistance to WCR. Thus, screening germplasm for WCR resistance should be made in a multi-year experiment, but not necessarily as a multi-location experiment. Resource optimization should be done by reducing number of roots per plot to minimum 4 sampled plants due to small within-plot environmental variance.

  1. Construction and functional analysis of Trichoderma harzianum mutants that modulate maize resistance to the pathogen Curvularia lunata.

    Science.gov (United States)

    Fan, Lili; Fu, Kehe; Yu, Chuanjin; Ma, Jia; Li, Yaqian; Chen, Jie

    2014-01-01

    Agrobacterium tumefaciens-mediated transformation (ATMT) was used to generate an insertional mutant library of the mycelial fungus Trichoderma harzianum. From a total of 450 mutants, six mutants that showed significant influence on maize resistance to C. lunata were analyzed in detail. Maize coated with these mutants was more susceptible to C. lunata compared with those coated with a wild-type (WT) strain. Similar to other fungal ATMT libraries, all six mutants were single copy integrations, which occurred preferentially in noncoding regions (except two mutants) and were frequently accompanied by the loss of border sequences. Two mutants (T66 and T312) that were linked to resistance were characterized further. Maize seeds coated with T66 and T312 were more susceptible to C. lunata than those treated with WT. Moreover, the mutants affected the resistance of maize to C. lunata by enhancing jasmonate-responsive gene expression. T66 and T312 induced maize resistance to C. lunata infection through a jasmonic acid-dependent pathway.

  2. Resistance of maize varieties to the maize weevil Sitophilus zeamais

    African Journals Online (AJOL)

    This study aimed at evaluating commonly used maize varieties, collected from Melkasa and Bako Agricultural Research Centers and Haramaya University, Ethiopia, against the maize weevil Sitophilus zeamais Motsch., one of the most important cosmopolitan stored product pests in maize. A total of 13 improved maize ...

  3. Imazapyr-resistant maize technology adoption for witch weed control ...

    African Journals Online (AJOL)

    Saharan Africa. A new technology known as imazapyr-resistant maize (IRM) has proven to be effective in controlling it. This study examined the status of IRM adoption in western Kenya. A cross sectional survey that included 600 households, ...

  4. Heritability and Components of Resistance to Cercospora zeae-maydis Derived from Maize Inbred VO613Y.

    Science.gov (United States)

    Gordon, Stuart G; Lipps, Patrick E; Pratt, Richard C

    2006-06-01

    ABSTRACT Gray leaf spot (GLS), caused by the fungus Cercospora zeae-maydis, is one of the most important foliar diseases of maize. This study was undertaken to estimate heritability of C. zeae-maydis resistance and examine the relationship between previously identified resistance loci and certain components of resistance including incubation period, lesion number, and maximum lesion length. Partially inbred progenies arising from hybridization between maize inbred lines VO613Y (high level of partial resistance) and Pa405 (susceptible) were examined in Ohio and South Africa. Heritability estimates of resistance were calculated based on severity and incubation period values. The range of heritability estimates based on severity was broad, with values ranging from approximately 0.46 to 0.81 (mean = 0.59). Estimates of mean heritability for incubation period were lowest (0.18), indicating that this component would likely be unsuitable for selection of germ plasm intended for deployment in diverse regions. Length of GLS lesions was significantly affected by host genotype, with resistant genotypes having shorter lesions from one site in Ohio during two seasons. Genotype also had a significant effect on incubation period and lesion number; the lower values for these components also were associated with resistant genotypes. The combined action of these resistance components resulted in lower overall disease severity.

  5. Enhanced pest resistance and increased phenolic production in maize callus transgenically expressing a maize chalcone isomerase -3 like gene

    Science.gov (United States)

    Significant losses in maize production are due to damage by insects and ear rot fungi. A gene designated as chalcone-isomerase-like, located in a quantitative trait locus for resistance to Fusarium ear rot fungi, was cloned from a Fusarium ear rot resistant inbred and transgenically expressed in mai...

  6. QTL mapping of resistance to gray leaf spot in maize.

    Science.gov (United States)

    Zhang, Yan; Xu, Ling; Fan, Xingming; Tan, Jing; Chen, Wei; Xu, Mingliang

    2012-12-01

    Gray leaf spot (GLS), caused by the causal fungal pathogen Cercospora zeae-maydis, is one of the most serious foliar diseases of maize worldwide. In the current study, a highly resistant inbred line Y32 and a susceptible line Q11 were used to produce segregating populations for both genetic analysis and QTL mapping. The broad-sense heritability (H (2)) for GLS resistance was estimated to be as high as 0.85, indicating that genetic factors played key roles in phenotypic variation. In initial QTL analysis, four QTL, located on chromosomes 1, 2, 5, and 8, were detected to confer GLS resistance. Each QTL could explain 2.53-23.90 % of the total phenotypic variation, predominantly due to additive genetic effects. Two major QTL, qRgls1 and qRgls2 on chromosomes 8 and 5, were consistently detected across different locations and replicates. Compared to the previous results, qRgls2 is located in a 'hotspot' for GLS resistance; while, qRgls1 does not overlap with any other known resistance QTL. Furthermore, the major QTL-qRgls1 was fine-mapped into an interval of 1.4 Mb, flanked by the markers GZ204 and IDP5. The QTL-qRgls1 could enhance the resistance percentages by 19.70-61.28 %, suggesting its usefulness to improve maize resistance to GLS.

  7. evaluation of striga-resistant early maize hybrids and test locations

    African Journals Online (AJOL)

    Prof. Adipala Ekwamu

    to evaluate selected Striga-resistant maize (Zea mays L.) hybrids for grain yield and stability of .... Analysis of variance procedure is useful for ... however, variance components alone do not ... for analysing multi-environment trial MET data.

  8. Water transfer in an alfalfa/maize association

    International Nuclear Information System (INIS)

    Corak, S.J.; Blevins, D.G.; Pallardy, S.G.

    1987-01-01

    The authors investigated the possibility of interspecific water transfer in an alfalfa (Medicago sativa L.) and maize (Zea mays L.) association. An alfalfa plant was grown through two vertically stacked plastic tubes. A 5 centimeter air gap between tubes was bridged by alfalfa roots. Five-week old maize plants with roots confined to the top tube were not watered, while associated alfalfa roots had free access to water in the bottom tube (the -/+ treatment). Additional treatments included: top and bottom tubes watered (+/+), top and bottom tubes droughted (-/-), and top tube droughted after removal of alfalfa root bridges and routine removal of alfalfa tillers (-*). Predawn leaf water potential of maize in the -/+ treatment fell to -1.5 megapascals 13 days after the start of drought; thereafter, predawn and midday potentials were maintained near -1.9 megapascals. Leaf water potentials of maize in the -/- and -* treatments declined steadily; all plants in these treatments were completely desiccated before day 50. High levels of tritium activity were detected in water extracted from both alfalfa and maize leaves after 3 H 2 O was injected into the bottom -/+ tube at day 70 or later. Maize in the -/+ treatment was able to survive an otherwise lethal period of drought by utilizing water lost by alfalfa roots

  9. Enhanced virus resistance in transgenic maize expressing a dsRNA-specific endoribonuclease gene from E. coli.

    Directory of Open Access Journals (Sweden)

    Xiuling Cao

    Full Text Available Maize rough dwarf disease (MRDD, caused by several Fijiviruses in the family Reoviridae, is a global disease that is responsible for substantial yield losses in maize. Although some maize germplasm have low levels of polygenic resistance to MRDD, highly resistant cultivated varieties are not available for agronomic field production in China. In this work, we have generated transgenic maize lines that constitutively express rnc70, a mutant E. coli dsRNA-specific endoribonuclease gene. Transgenic lines were propagated and screened under field conditions for 12 generations. During three years of evaluations, two transgenic lines and their progeny were challenged with Rice black-streaked dwarf virus (RBSDV, the causal agent of MRDD in China, and these plants exhibited reduced levels of disease severity. In two normal years of MRDD abundance, both lines were more resistant than non-transgenic plants. Even in the most serious MRDD year, six out of seven progeny from one line were resistant, whereas non-transgenic plants were highly susceptible. Molecular approaches in the T12 generation revealed that the rnc70 transgene was integrated and expressed stably in transgenic lines. Under artificial conditions permitting heavy virus inoculation, the T12 progeny of two highly resistant lines had a reduced incidence of MRDD and accumulation of RBSDV in infected plants. In addition, we confirmed that the RNC70 protein could bind directly to RBSDV dsRNA in vitro. Overall, our data show that RNC70-mediated resistance in transgenic maize can provide efficient protection against dsRNA virus infection.

  10. Sensory characteristics of high-amylose maize-resistant starch in three food products

    OpenAIRE

    Maziarz, Mindy; Sherrard, Melanie; Juma, Shanil; Prasad, Chandan; Imrhan, Victorine; Vijayagopal, Parakat

    2012-01-01

    Type 2 resistant starch from high-amylose maize (HAM-RS2) is considered a functional ingredient due to its positive organoleptic and physiochemical modifications associated with food and physiological benefits related to human health. The sensory characteristics of three types of food products (muffins, focaccia bread, and chicken curry) with and without HAM-RS2 were evaluated using a 9-point hedonic scale. The HAM-RS2-enriched muffins, focaccia bread, and chicken curry contained 5.50 g/100 g...

  11. Characterization of Sugarcane Mosaic Virus Scmv1 and Scmv2 Resistance Regions by Regional Association Analysis in Maize.

    Directory of Open Access Journals (Sweden)

    Pengfei Leng

    Full Text Available Sugarcane Mosaic Virus (SCMV causes one of the most severe virus diseases in maize worldwide, resulting in reduced grain and forage yield in susceptible cultivars. In this study, two association panels consisting of 94 inbred lines each, from China and the U.S., were characterized for resistance to two isolates: SCMV-Seehausen and SCMV-BJ. The population structure of both association panels was analyzed using 3072 single nucleotide polymorphism (SNP markers. The Chinese and the U.S. panel were both subdivided into two sub-populations, the latter comprised of Stiff Stalk Synthetic (SS lines and Non Stiff Stalk Synthetic (NSS. The relative kinships were calculated using informative 2947 SNPs with minor allele frequency ≥ 5% and missing data ≤ 20% for the Chinese panel and 2841 SNPs with the same characteristics were used for the U.S. panel. The Scmv1 region was genotyped using 7 single sequence repeat (SSR and sequence-tagged site (STS markers, and 12 SSR markers were used for the Scmv2 region in the U.S. panel, while 5 of them were used for the Chinese panel. For all traits, a MLM (Mix Linear Model controlling both population structure and relative kinship (Q + K was used for association analysis. Three markers Trx-1, STS-11, and STS-12 located in the Scmv1 region were strongly associated (P = 0.001 with SCMV resistance, and explained more than 16.0%, 10.6%, and 19.7% of phenotypic variation, respectively. 207FG003 located in the Scmv2 region was significantly associated (P = 0.001 with SCMV resistance, and explained around 18.5% of phenotypic variation.

  12. Performance and cross-crop resistance of Cry1F-maize selected Spodoptera frugiperda on transgenic Bt cotton: implications for resistance management.

    Science.gov (United States)

    Yang, Fei; Kerns, David L; Brown, Sebe; Kurtz, Ryan; Dennehy, Tim; Braxton, Bo; Head, Graham; Huang, Fangneng

    2016-06-15

    Transgenic crops producing Bacillus thuringiensis (Bt) proteins have become a primary tool in pest management. Due to the intensive use of Bt crops, resistance of the fall armyworm, Spodoptera frugiperda, to Cry1F maize has occurred in Puerto Rico, Brazil, and some areas of the southeastern U.S. The sustainability of Bt crops faces a great challenge because the Cry1F-maize resistant S. frugiperda may also infest other Bt crops in multiple cropping ecosystems. Here we examined the survival and plant injury of a S. frugiperda population selected with Cry1F maize on three single-gene and five pyramided Bt cotton products. Larvae of Cry1F-susceptible (SS), -heterozygous (RS), and -resistant (RR) genotypes of S. frugiperda were all susceptible to the pyramided cotton containing Cry1Ac/Cry2Ab, Cry1Ac/Cry1F/Vip3A, Cry1Ab/Cry2Ae, or Cry1Ab/Cry2Ae/Vip3A, and the single-gene Cry2Ae cotton. Pyramided cotton containing Cry1Ac/Cry1F was effective against SS and RS, but not for RR. These findings show that the Cry1F-maize selected S. frugiperda can cause cross-crop resistance to other Bt crops expressing similar insecticidal proteins. Resistance management and pest management programs that utilize diversify mortality factors must be implemented to ensure the sustainability of Bt crops. This is especially important in areas where resistance to single-gene Bt crops is already widespread.

  13. Dominance of Cry1F resistance in Spodoptera frugiperda (Lepidoptera: Noctuidae) on TC1507 Bt maize in Brazil.

    Science.gov (United States)

    Farias, Juliano R; Andow, David A; Horikoshi, Renato J; Sorgatto, Rodrigo J; dos Santos, Antonio C; Omoto, Celso

    2016-05-01

    Dominance of resistance has been one of the major parameters affecting the rate of evolution of resistance to Bt crops. High dose is the capacity of Bt crops to kill heterozygous insects and has been an essential component of the most successful strategy to manage resistance to these crops. Experiments were conducted to evaluate directly and indirectly whether the TC1507 event is high dose to Spodoptera frugiperda (JE Smith). About 8% of heterozygote neonate larvae were able to survive, complete larval development and emerge as normal adults on TC1507 leaves, while susceptible larvae could not survive for 5 days. The estimated dominance of resistance was 0.15 ± 0.09 and significantly higher than zero; therefore, the resistance to Cry1F expressed in TC1507 was not completely recessive. A 25-fold dilution of TC1507 maize leaf tissue in an artificial diet was able to cause a maximum mortality of only 37%, with growth inhibition of 82% at 7 days after larval infestation. Resistance to Cry1F in TC1507 maize is incompletely recessive in S. frugiperda. TC1507 maize is not high dose for S. frugiperda. Additional or alternative resistance management strategies, such as the replacement of single-trait Bt maize with pyramided Bt maize, which produces multiple proteins targeting the same insect pests, should be implemented wherever this technology is in use and S. frugiperda is the major pest. © 2015 Society of Chemical Industry.

  14. A maize resistance gene functions against bacterial streak disease in rice

    OpenAIRE

    Zhao, Bingyu; Lin, Xinghua; Poland, Jesse; Trick, Harold; Leach, Jan; Hulbert, Scot

    2005-01-01

    Although cereal crops all belong to the grass family (Poacea), most of their diseases are specific to a particular species. Thus, a given cereal species is typically resistant to diseases of other grasses, and this nonhost resistance is generally stable. To determine the feasibility of transferring nonhost resistance genes (R genes) between distantly related grasses to control specific diseases, we identified a maize R gene that recognizes a rice pathogen, Xanthomonas oryzae pv. oryzicola, wh...

  15. Root inoculation with Pseudomonas putida KT2440 induces transcriptional and metabolic changes and systemic resistance in maize plants

    Directory of Open Access Journals (Sweden)

    Chantal ePlanchamp

    2015-01-01

    Full Text Available Pseudomonas putida KT2440 (KT2440 rhizobacteria colonize a wide range of plants. They have been extensively studied for their capacity to adhere to maize seeds, to tolerate toxic secondary metabolites produced by maize roots and to be attracted by maize roots. However, the response of maize plants to KT2440 colonization has not been investigated yet. Maize roots were inoculated with KT2440 and the local (roots and systemic (leaves early plant responses were investigated. The colonization behavior of KT2440 following application to maize seedlings was investigated and transcriptional analysis of stress- and defense-related genes as well as metabolite profiling of local and systemic maize tissues of KT2440-inoculated were performed. The local and systemic responses differed and more pronounced changes were observed in roots compared to leaves. Early in the interaction roots responded via jasmonic acid- and abscisic acid-dependent signaling. Interestingly, during later steps, the salicylic acid pathway was suppressed. Metabolite profiling revealed the importance of plant phospholipids in KT2440-maize interactions. An additional important maize secondary metabolite, a form of benzoxazinone, was also found to be differently abundant in roots three days after KT2440 inoculation. However, the transcriptional and metabolic changes observed in bacterized plants early during the interaction were minor and became even less pronounced with time, indicating an accommodation state of the plant to the presence of KT2440. Since the maize plants reacted to the presence of KT2440 in the rhizosphere, we also investigated the ability of these bacteria to trigger induced systemic resistance (ISR against the maize anthracnose fungus Colletotrichum graminicola. The observed resistance was expressed as strongly reduced leaf necrosis and fungal development in infected bacterized plants compared to non-bacterized controls, showing the potential of KT2440 to act as

  16. Maize-Pathogen Interactions: An Ongoing Combat from a Proteomics Perspective

    Directory of Open Access Journals (Sweden)

    Olga Pechanova

    2015-11-01

    Full Text Available Maize (Zea mays L. is a host to numerous pathogenic species that impose serious diseases to its ear and foliage, negatively affecting the yield and the quality of the maize crop. A considerable amount of research has been carried out to elucidate mechanisms of maize-pathogen interactions with a major goal to identify defense-associated proteins. In this review, we summarize interactions of maize with its agriculturally important pathogens that were assessed at the proteome level. Employing differential analyses, such as the comparison of pathogen-resistant and susceptible maize varieties, as well as changes in maize proteomes after pathogen challenge, numerous proteins were identified as possible candidates in maize resistance. We describe findings of various research groups that used mainly mass spectrometry-based, high through-put proteomic tools to investigate maize interactions with fungal pathogens Aspergillus flavus, Fusarium spp., and Curvularia lunata, and viral agents Rice Black-streaked Dwarf Virus and Sugarcane Mosaic Virus.

  17. Maize-Pathogen Interactions: An Ongoing Combat from a Proteomics Perspective.

    Science.gov (United States)

    Pechanova, Olga; Pechan, Tibor

    2015-11-30

    Maize (Zea mays L.) is a host to numerous pathogenic species that impose serious diseases to its ear and foliage, negatively affecting the yield and the quality of the maize crop. A considerable amount of research has been carried out to elucidate mechanisms of maize-pathogen interactions with a major goal to identify defense-associated proteins. In this review, we summarize interactions of maize with its agriculturally important pathogens that were assessed at the proteome level. Employing differential analyses, such as the comparison of pathogen-resistant and susceptible maize varieties, as well as changes in maize proteomes after pathogen challenge, numerous proteins were identified as possible candidates in maize resistance. We describe findings of various research groups that used mainly mass spectrometry-based, high through-put proteomic tools to investigate maize interactions with fungal pathogens Aspergillus flavus, Fusarium spp., and Curvularia lunata, and viral agents Rice Black-streaked Dwarf Virus and Sugarcane Mosaic Virus.

  18. Genetic characterization and linkage disequilibrium mapping of resistance to gray leaf spot in maize (Zea mays L.

    Directory of Open Access Journals (Sweden)

    Liyu Shi

    2014-04-01

    Full Text Available Gray leaf spot (GLS, caused by Cercospora zeae-maydis, is an important foliar disease of maize (Zea mays L. worldwide, resistance to which is controlled by multiple quantitative trait loci (QTL. To gain insights into the genetic architecture underlying the resistance to this disease, an association mapping population consisting of 161 inbred lines was evaluated for resistance to GLS in a plant pathology nursery at Shenyang in 2010 and 2011. Subsequently, a genome-wide association study, using 41,101 single-nucleotide polymorphisms (SNPs, identified 51 SNPs significantly (P < 0.001 associated with GLS resistance, which could be converted into 31 QTL. In addition, three candidate genes related to plant defense were identified, including nucleotide-binding-site/leucine-rich repeat, receptor-like kinase genes similar to those involved in basal defense. Two genic SNPs, PZE-103142893 and PZE-109119001, associated with GLS resistance in chromosome bins 3.07 and 9.07, can be used for marker-assisted selection (MAS of GLS resistance. These results provide an important resource for developing molecular markers closely linked with the target trait, enhancing breeding efficiency.

  19. Difference between resistant and susceptible maize to systematic colonization as revealed by DsRed-labeled Fusarium verticillioides

    Directory of Open Access Journals (Sweden)

    Lei Wu

    2013-10-01

    Full Text Available Fusarium verticillioides was labeled with DsRed via Agrobacterium tumefaciens-mediated transformation to examine differences in colonization and reactions of resistant and susceptible inbred lines of maize (Zea mays L.. The extent of systemic colonization of F. verticillioides in roots from maize lines either resistant or susceptible to the fungus was studied by visualizing the red fluorescence produced by the fungus expressing DsRed. The difference in quantities of colony forming units (CFU in roots and basal stems, production of fumonisin B1, and pH of root were determined. Although F. verticillioides colonized both resistant and susceptible lines, differences were observed in the pattern and extent of fungal colonization in the two types of maize lines. The fungus colonized the susceptible lines producing mosaic patterns by filling the individual root cells with hyphae. Such a pattern of colonization was rarely observed in resistant lines, which were less colonized by the fungus than the susceptible lines in terms of CFUs. The production of mycotoxin fumonisin B1 in roots from different lines was closely correlated with the amount of F. verticillioides colonization, rather than the pH or amylopectin concentrations in the root. The findings from this study contribute to a better understanding of the defense mechanism in resistant maize lines to F. verticillioides.

  20. The roles of organic anion permeases in aluminium resistance and mineral nutrition.

    Science.gov (United States)

    Delhaize, Emmanuel; Gruber, Benjamin D; Ryan, Peter R

    2007-05-25

    Soluble aluminium (Al(3+)) is the major constraint to plant growth on acid soils. Plants have evolved mechanisms to tolerate Al(3+) and one type of mechanism relies on the efflux of organic anions that protect roots by chelating the Al(3+). Al(3+) resistance genes of several species have now been isolated and found to encode membrane proteins that facilitate organic anion efflux from roots. These proteins belong to the Al(3+)-activated malate transporter (ALMT) and multi-drug and toxin extrusion (MATE) families. We review the roles of these proteins in Al(3+) resistance as well as their roles in other aspects of mineral nutrition.

  1. Comparative QTL mapping of resistance to sugarcane mosaic virus in maize based on bioinformatics

    Institute of Scientific and Technical Information of China (English)

    Xiangling L(U); Xinhai LI; Chuanxiao XIE; Zhuanfang HAO; Hailian JI; Liyu SHI; Shihuang ZHANG

    2008-01-01

    The development of genomics and bioinfor-matics offers new tools for comparative gene mapping. In this paper, an integrated QTL map for sugarcane mosaic virus (SCMV) resistance in maize was constructed by compiling a total of 81 QTL loci available, using the Genetic Map IBM2 2005 Neighbors as reference. These 81 QTL loci were scattered on 7 chromosomes of maize, and most of them were clustered on chromosomes 3 and 6. By using the method of meta-analysis, we identified one "consensus QTL" on chromosome 3 covering a genetic distance of 6.44 cM, and two on chromosome 6 covering genetic distances of 16 cM and 27.48 cM, respectively. Four positional candidate resistant genes were identified within the "consensus QTL" on chromosome 3 via the strategy of comparative genomics. These results suggest that application of a combination of meta-analysis within a species with sequence homology comparison in a related model plant is an efficient approach to identify the major QTL and its candidate gene(s) for the target traits. The results of this study provide useful information for iden-tifying and cloning the major gene(s) conferring resistance to SCMV in maize.

  2. Evaluation of ear rot (Fusarium verticillioides resistance and fumonisin accumulation in Italian maize inbred lines

    Directory of Open Access Journals (Sweden)

    Carlotta BALCONI

    2014-05-01

    Full Text Available Mycotoxin contamination of maize (Zea mays L. grain is a global threat to the safety of both human food and animal feed. Hence, the development of maize genotypes with reduced mycotoxin accumulation in grain is of major importance. In order to find maize germplasm sources of resistance to Fusarium ear rot, 34 Italian and six public inbred lines were evaluated by means of artificial inoculation in field experiments during 2009 and 2010. Relationships between ear rot and fumonisin concentration in the ears were investigated. Primary ears were challenged with a mixture of two Fusarium verticillioides isolates from Northern Italy, through kernel inoculation, and ear rot severity was assessed.The average number of visibly infected kernels per ear, after inoculation, ranged from 2 to 68 in 2009 and from 0 to 120 in 2010. Fumonisin concentrations in the inoculated ears were greater than in the experimental controls for both years. Variability was found between the inbred lines: fumonisin accumulation ranged from 0.56 to 240.83 mg kg-1 in 2009 and from 1.09 to 190.60 mg kg-1 in 2010. In both years, six inbred lines showed high fumonisin content (≥100 mg kg-1, while the other genotypes were almost equally split into two groups, low (≤10 mg kg-1 and medium (from 11 to 100 mg kg-1 fumonisin content. The number of infected kernels after artificial inoculation correlated with fumonisin concentration both in 2009 (r = 0.94; P≤0.01 and 2010 (r = 0.67; P≤0.01. Additionally, the percentage of internally infected kernels correlated positively with fumonisin concentration (r = 0.37; P≤0.01 and with the number of infected kernels (r = 0.29; P≤0.05. This research has demonstrated that Italian maize germplasm is a valid source of resistance to Fusarium ear rot. Furthermore, there is a strong association of visible Fusarium symptoms with fumonisin concentration, suggesting that selection in maize for reduced visible moulds should reduce the risk of

  3. Evaluation of maize inbred lines for resistance to pre-harvest aflatoxin and fumonisin contamination in the field

    Science.gov (United States)

    Two important mycotoxins, aflatoxin and fumonisin, are among the most potent naturally occurring carcinogens, contaminating maize (Zea mays L.) and affecting the crop yield and quality. Resistance of maize to pre-harvest mycotoxin contamination, specifically aflatoxin produced by Aspergillus flavus ...

  4. Comparative impact of genetically modified and non modified maize (Zea mays L.) on succeeding crop and associated weed.

    Science.gov (United States)

    Ibrahim, Muhammad; Ahmed, Naseer; Ullah, Faizan; Shinwari, Zabta Khan; Bano, Asghari

    2016-04-01

    This research work documents the comparative impact of genetically modified (GM) (insect resistance) and non modified maize (Zea mays L.) on growth and germination of succeeding crop wheat (Triticum aestivum L.) and associated weed (Avena fatua L.). The aqueous extracts of both the GM and non-GM maize exhibited higher phenolic content than that of methanolic extracts. Germination percentage and germination index of wheat was significantly decreased by GM methanolic extract (10%) as well as that of non-GM maize at 3% aqueous extract. Similarly germination percentage of weed (Avena fatua L.) was significantly reduced by application of 3% and 5% methanolic GM extracts. All extracts of GM maize showed non-significant effect on the number of roots, root length and shoot length per plant but 5% and 10% methanolic extracts of non-GM maize significantly increased the number of roots per plant of wheat seedling. Similarly, 10% methanolic extract of GM maize significantly increased the number of roots per plant of weed seedling. Methanolic extracts of GM and non-GM maize (3% and 5%) significantly decreased the protease activity in wheat as compared to untreated control. © The Author(s) 2013.

  5. Spodoptera frugiperda (J.E. Smith) with field-evolved resistance to Bt maize are susceptible to Bt pesticides.

    Science.gov (United States)

    Jakka, S R K; Knight, V R; Jurat-Fuentes, J L

    2014-10-01

    Field-evolved resistance to maize event TC1507 expressing the Cry1Fa toxin from Bacillus thuringiensis (Bt) was detected in populations of Spodoptera frugiperda from Puerto Rico. We tested for cross-resistance to purified Cry1A toxins and commercial Bt pesticides in susceptible (Benzon) and TC1507-resistant (456) strains of S. frugiperda. Larvae from the 456 strain exhibited cross-resistance to Cry1Ab and Cry1Ac toxins, while no differences in susceptibility to XenTari WG and DiPel ES pesticides were detected. These data support cross-resistance to toxins that share binding sites with Cry1Fa and no cross-resistance to Bt pesticides in S. frugiperda with field-evolved resistance to Bt maize. Copyright © 2014 Elsevier Inc. All rights reserved.

  6. Potential roles of WRKY transcription factors in resistance to Aspergillus flavus colonization of immature maize kernels

    Science.gov (United States)

    Resistance to Aspergillus flavus by maize (Zea mays L.) is mediated by several defense proteins; however the mechanism regulating the expression of these defenses is poorly understood. This study examined the potential roles of six maize WRKY transcription factors, ZmWRKY19, ZmWRKY21, ZmWRKY53, ZmW...

  7. [A method for genetic transformation of maize for resistance to viral diseases].

    Science.gov (United States)

    Valdez, Marta; Madriz, Kenneth; Ramírez, Pilar

    2004-09-01

    A system for the genetic transformation of maize was developed for two Costa Rican varieties: CR-7 and Diamantes 8843, that can allow the subsequent transfer of viral-derived genes in order to confer resistance to the disease caused by maize rayado fino virus (MRFV). The method is based on particle bombardment of organogenic calli derived from shoot tips. On the other hand, the molecular construction pRFcp-bar, containing the coat protein gene of MRFV and the marker gene bar, was elaborated. For the visual selection of the transformed material was used also the plasmid pDM803 that contains the reporter gene uidA (GUS). The results indicate that devices evaluated: the PIG ("Particle Inflow Gun") and the Bio-Rad are both enough efficient to transfer foreign genes to the genome of the maize.

  8. Evaluation of new generation maize steak virus (MSV) resistant ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-10-05

    Oct 5, 2009 ... Five new generations of maize streak virus (MSV) resistant varieties were evaluated along with two checks in replicated trials ..... Year (Y). 60.07*. 0.88. 3.45. 10.45*. 50.16. 4.57. 2.16. Genotype (G). 4.61*. 1.24. 4.46. 8.46*. 7.91*. 227.83**. 5.19**. Y x G. 3.41. 1.08. 2.43. 4.89. 2.79. 137.66. 1.08. %CV. 1.91.

  9. Diallel crossing among maize populations for resistance to fall armyworm

    Directory of Open Access Journals (Sweden)

    Alvarez María del Pilar

    2002-01-01

    Full Text Available Among the insects infecting the maize (Zea mays L. crop in Brazil, the fall armyworm (Spodoptera frugiperda Smith, 1797, Lepdoptera: Noctuidae is considered one of the most important because it causes the highest damage to yield. Genetic resistance to the fall armyworm has be an effective control strategy. The main objective of this work was to evaluate new germplasm sources for resistance to the fall armyworm, the key pest for the maize crop in Brazil. A partial diallel design between 20 varieties of Brazilian germplasm and nine exotic and semi-exotic varieties of different origin was used. The 180 crosses and 29 parental varieties along with two commercial checks were evaluated in three locations in the State of São Paulo State (Brasil. Fall armyworm resistance (FAWR under artificial and natural infestations, grain yield (GY, and plant height (PH were analyzed. The populations CMS14C and MIRT, and hybrid São José x MIRT showed the highest resistance, with values of 1.8, 1.7 and 1.4, respectively. Populations PMI9401 and PR91B, and the hybrid CMS14C x (B97xITU had best yields, with 4893, 3858 and 5677 kg ha-1, respectively. Heterosis ranged from -28% to 47% for FAWR and from -21% to 125% for GY, with mean values of -0,43% and 31%, respectively. Genotype by environment interaction was not significant for FAWR. The effects of varieties and heterosis were significant for all traits, showing that both additive and dominance effects may be important as sources of variation. For FAWR, only specific heterosis presented significance, suggesting strong genetic divergence between specific pairs of parental populations. Brasilian populations PMI9302 and São José, and the exotic population PR91B presented high performance per se, and also in croses for FAWR and GY. Crosses PMI9401 x (Cuba110 x EsalqPB1 and São José x MIRT presented high specific heterosis effects for both characters. These populations can be useful to be introgressed in maize

  10. Resistance to gray leaf spot of maize: genetic architecture and mechanisms elucidated through nested association mapping and near-isogenic line analysis.

    Science.gov (United States)

    Benson, Jacqueline M; Poland, Jesse A; Benson, Brent M; Stromberg, Erik L; Nelson, Rebecca J

    2015-03-01

    Gray leaf spot (GLS), caused by Cercospora zeae-maydis and Cercospora zeina, is one of the most important diseases of maize worldwide. The pathogen has a necrotrophic lifestyle and no major genes are known for GLS. Quantitative resistance, although poorly understood, is important for GLS management. We used genetic mapping to refine understanding of the genetic architecture of GLS resistance and to develop hypotheses regarding the mechanisms underlying quantitative disease resistance (QDR) loci. Nested association mapping (NAM) was used to identify 16 quantitative trait loci (QTL) for QDR to GLS, including seven novel QTL, each of which demonstrated allelic series with significant effects above and below the magnitude of the B73 reference allele. Alleles at three QTL, qGLS1.04, qGLS2.09, and qGLS4.05, conferred disease reductions of greater than 10%. Interactions between loci were detected for three pairs of loci, including an interaction between iqGLS4.05 and qGLS7.03. Near-isogenic lines (NILs) were developed to confirm and fine-map three of the 16 QTL, and to develop hypotheses regarding mechanisms of resistance. qGLS1.04 was fine-mapped from an interval of 27.0 Mb to two intervals of 6.5 Mb and 5.2 Mb, consistent with the hypothesis that multiple genes underlie highly significant QTL identified by NAM. qGLS2.09, which was also associated with maturity (days to anthesis) and with resistance to southern leaf blight, was narrowed to a 4-Mb interval. The distance between major leaf veins was strongly associated with resistance to GLS at qGLS4.05. NILs for qGLS1.04 were treated with the C. zeae-maydis toxin cercosporin to test the role of host-specific toxin in QDR. Cercosporin exposure increased expression of a putative flavin-monooxygenase (FMO) gene, a candidate detoxification-related gene underlying qGLS1.04. This integrated approach to confirming QTL and characterizing the potential underlying mechanisms advances the understanding of QDR and will facilitate the

  11. Resistance to gray leaf spot of maize: genetic architecture and mechanisms elucidated through nested association mapping and near-isogenic line analysis.

    Directory of Open Access Journals (Sweden)

    Jacqueline M Benson

    2015-03-01

    Full Text Available Gray leaf spot (GLS, caused by Cercospora zeae-maydis and Cercospora zeina, is one of the most important diseases of maize worldwide. The pathogen has a necrotrophic lifestyle and no major genes are known for GLS. Quantitative resistance, although poorly understood, is important for GLS management. We used genetic mapping to refine understanding of the genetic architecture of GLS resistance and to develop hypotheses regarding the mechanisms underlying quantitative disease resistance (QDR loci. Nested association mapping (NAM was used to identify 16 quantitative trait loci (QTL for QDR to GLS, including seven novel QTL, each of which demonstrated allelic series with significant effects above and below the magnitude of the B73 reference allele. Alleles at three QTL, qGLS1.04, qGLS2.09, and qGLS4.05, conferred disease reductions of greater than 10%. Interactions between loci were detected for three pairs of loci, including an interaction between iqGLS4.05 and qGLS7.03. Near-isogenic lines (NILs were developed to confirm and fine-map three of the 16 QTL, and to develop hypotheses regarding mechanisms of resistance. qGLS1.04 was fine-mapped from an interval of 27.0 Mb to two intervals of 6.5 Mb and 5.2 Mb, consistent with the hypothesis that multiple genes underlie highly significant QTL identified by NAM. qGLS2.09, which was also associated with maturity (days to anthesis and with resistance to southern leaf blight, was narrowed to a 4-Mb interval. The distance between major leaf veins was strongly associated with resistance to GLS at qGLS4.05. NILs for qGLS1.04 were treated with the C. zeae-maydis toxin cercosporin to test the role of host-specific toxin in QDR. Cercosporin exposure increased expression of a putative flavin-monooxygenase (FMO gene, a candidate detoxification-related gene underlying qGLS1.04. This integrated approach to confirming QTL and characterizing the potential underlying mechanisms advances the understanding of QDR and will

  12. IMAZAPYR-RESISTANT MAIZE TECHNOLOGY ADOPTION FOR ...

    African Journals Online (AJOL)

    Prof. Adipala Ekwamu

    decisions by protecting maize (Zea mays L.) crop in western Kenya from Striga. Key Words: Adopters, Zea ... Africa, efficient and profitable production of maize is severely constrained by ..... gap by understanding its source. African. Journal of ...

  13. Monitoring of Sesamia nonagrioides resistance to MON 810 maize in the European Union: lessons from a long-term harmonized plan.

    Science.gov (United States)

    Farinós, Gema P; Hernández-Crespo, Pedro; Ortego, Félix; Castañera, Pedro

    2018-03-01

    Use of MON 810 maize (Zea mays), which expresses the insecticidal protein Cry1Ab from Bacillus thuringiensis (Bt maize), is a highly effective method to control Sesamia nonagrioides (Lefèbvre), a key maize pest in Mediterranean countries. Monitoring programs to assess the potential development of resistance of target pests to Bt maize are mandatory in the European Union (EU). Here we report the results of the S. nonagrioides resistance monitoring plan implemented for MON 810 maize in the EU between 2004 and 2015 and reassess the different components of this long-term harmonized plan. No major shifts in the susceptibility of S. nonagrioides to the Cry1Ab protein have occurred over time. The reassessment of this long-term program has identified some practical and technical constraints, allowing us to provide specific recommendations for improvement: use reference strains instead of susceptibility baselines as comparators for field-collected populations; shift from dose-response bioassays to diagnostic concentrations; and focus monitoring on areas with high adoption rates, such as the Ebro basin in Spain. There are no signs of field resistance of S. nonagrioides to the Cry1Ab protein of MON 810 maize. Specific recommendations for improvement are provided, based on the knowledge and experience accumulated through the implementation of this unique EU-wide harmonized plan. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  14. Genetics of Resistance and Pathogenicity in the Maize/Setosphaeria turcica Pathosystem and Implications for Breeding

    Directory of Open Access Journals (Sweden)

    Ana L. Galiano-Carneiro

    2017-08-01

    Full Text Available Northern corn leaf blight (NCLB, the most devastating leaf pathogen in maize (Zea mays L., is caused by the heterothallic ascomycete Setosphaeria turcica. The pathogen population shows an extremely high genetic diversity in tropical and subtropical regions. Varietal resistance is the most efficient technique to control NCLB. Host resistance can be qualitative based on race-specific Ht genes or quantitative controlled by many genes with small effects. Quantitative resistance is moderately to highly effective and should be more durable combatting all races of the pathogen. Quantitative resistance must, however, be analyzed in many environments (= location × year combinations to select stable resistances. In the tropical and subtropical environments, quantitative resistance is the preferred option to manage NCLB epidemics. Resistance level can be increased in practical breeding programs by several recurrent selection cycles based on disease severity rating and/or by genomic selection. This review aims to address two important aspects of the NCLB pathosystem: the genetics of the fungus S. turcica and the modes of inheritance of the host plant maize, including successful breeding strategies regarding NCLB resistance. Both drivers of this pathosystem, pathogen, and host, must be taken into account to result in more durable resistance.

  15. Origin of negative resistance in anion migration controlled resistive memory

    Science.gov (United States)

    Banerjee, Writam; Wu, Facai; Hu, Yuan; Wu, Quantan; Wu, Zuheng; Liu, Qi; Liu, Ming

    2018-03-01

    Resistive random access memory (RRAM) is one of the most promising emerging nonvolatile technologies for the futuristic memory devices. Resistive switching behavior often shows negative resistance (NR), either voltage controlled or current controlled. In this work, the origin of a current compliance dependent voltage controlled NR effect during the resetting of anion migration based RRAM devices is discussed. The N-type voltage controlled NR is a high field driven phenomena. The current conduction within the range of a certain negative voltage is mostly dominated by space charge limited current. But with the higher negative voltage, a field induced tunneling effect is generated in the NR region. The voltage controlled NR is strongly dependent on the compliance current. The area independent behavior indicates the filamentary switching. The peak to valley ratio (PVR) is > 5. The variation of PVR as a function of the conduction band offset is achieved. Compared to other reported works, based on the PVR, it is possible to distinguish the RRAM types. Generally, due to the higher electric field effect on the metallic bridge during RESET, the electrochemical metallization type RRAM shows much higher PVR than the valance change type RRAM.

  16. Comparative transcriptome proifling of two maize near-isogenic lines differing in the allelic state for bacterial brown spot disease resistance

    Institute of Scientific and Technical Information of China (English)

    WU Xiao-jun; Xu Li; ZHAO Pan-feng; LI Na; WU Lei; HE Yan; WANG Shou-cai

    2015-01-01

    The bacterial brown spot disease (BBS), caused primarily by Pseudomonas syringae pv. syringae van Hal (Pss), reduces plant vigor, yield and quality in maize. To reveal the nature of the defense mechanisms and identify genes involved in the effective host resistance, the dynamic changes of defense transcriptome triggered by the infection of Pss were investigated and compared between two maize near-isogenic lines (NILs). We found that Pss infection resulted in a sophisticated tran-scriptional reprogramming of several biological processes and the resistant NIL employed much faster defense responses than the susceptible NIL. Numerous genes encoding essential components of plant basal resistance would be able to be activated in the susceptible NIL, such as PEN1, PEN2, PEN3, and EDR1, however, in a basic manner, such resistance might not be sufifcient for suppressing Pss pathogenesis. In addition, the expressions of a large number of PTI-, ETI-, PR-, and WRKY-related genes were pronouncedly activated in the resistant NIL, suggesting that maize employ a multitude of defense pathways to defend Pss infection. Six R-gene homologs were identiifed to have signiifcantly higher expression levels in the resistant NIL at early time point, indicating that a robust surveil ance system (gene-to-gene model) might operate in maize during Pss attacks, and these homolog genes are likely to be potential candidate resistance genes involved in BBS disease resistance. Furthermore, a holistic group of novel pathogen-responsive genes were deifned, providing the repertoire of candidate genes for further functional characterization and identiifcation of their regulation patterns during pathogen infection.

  17. Genetic Factors Involved in Fumonisin Accumulation in Maize Kernels and Their Implications in Maize Agronomic Management and Breeding.

    Science.gov (United States)

    Santiago, Rogelio; Cao, Ana; Butrón, Ana

    2015-08-20

    Contamination of maize with fumonisins depends on the environmental conditions; the maize resistance to contamination and the interaction between both factors. Although the effect of environmental factors is a determinant for establishing the risk of kernel contamination in a region, there is sufficient genetic variability among maize to develop resistance to fumonisin contamination and to breed varieties with contamination at safe levels. In addition, ascertaining which environmental factors are the most important in a region will allow the implementation of risk monitoring programs and suitable cultural practices to reduce the impact of such environmental variables. The current paper reviews all works done to address the influence of environmental variables on fumonisin accumulation, the genetics of maize resistance to fumonisin accumulation, and the search for the biochemical and/or structural mechanisms of the maize plant that could be involved in resistance to fumonisin contamination. We also explore the outcomes of breeding programs and risk monitoring of undertaken projects.

  18. Characterization of the maize lipoxygenase gene family in relation to aflatoxin accumulation resistance

    Science.gov (United States)

    Oluwaseun F. Ogunola; Leigh K. Hawkins; Erik Mylroie; Michael V. Kolomiets; Eli Borrego; Juliet D. Tang; Paul W. Williams; Marilyn L. Warburton

    2017-01-01

    Maize (Zea mays L.) is a globally important staple food crop prone to contamination by aflatoxin, a carcinogenic secondary metabolite produced by the fungus Aspergillus flavus. An efficient approach to reduce accumulation of aflatoxin is the development of germplasm resistant to colonization and toxin...

  19. Quantitative Trait Loci Mapping of Western Corn Rootworm (Coleoptera: Chrysomelidae) Host Plant Resistance in Two Populations of Doubled Haploid Lines in Maize (Zea mays L.).

    Science.gov (United States)

    Bohn, Martin O; Marroquin, Juan J; Flint-Garcia, Sherry; Dashiell, Kenton; Willmot, David B; Hibbard, Bruce E

    2018-02-09

    Over the last 70 yr, more than 12,000 maize accessions have been screened for their level of resistance to western corn rootworm, Diabrotica virgifera virgifera (LeConte; Coleoptera: Chrysomelidae), larval feeding. Less than 1% of this germplasm was selected for initiating recurrent selection or other breeding programs. Selected genotypes were mostly characterized by large root systems and superior root regrowth after root damage caused by western corn rootworm larvae. However, no hybrids claiming native (i.e., host plant) resistance to western corn rootworm larval feeding are currently commercially available. We investigated the genetic basis of western corn rootworm resistance in maize materials with improved levels of resistance using linkage disequilibrium mapping approaches. Two populations of topcrossed doubled haploid maize lines (DHLs) derived from crosses between resistant and susceptible maize lines were evaluated for their level of resistance in three to four different environments. For each DHL topcross an average root damage score was estimated and used for quantitative trait loci (QTL) analysis. We found genomic regions contributing to western corn rootworm resistance on all maize chromosomes, except for chromosome 4. Models fitting all QTL simultaneously explained about 30 to 50% of the genotypic variance for root damage scores in both mapping populations. Our findings confirm the complex genetic structure of host plant resistance against western corn rootworm larval feeding in maize. Interestingly, three of these QTL regions also carry genes involved in ascorbate biosynthesis, a key compound we hypothesize is involved in the expression of western corn rootworm resistance. © The Author(s) 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  20. Expression Analysis of Stress-Related Genes in Kernels of Different Maize (Zea mays L.) Inbred Lines with Different Resistance to Aflatoxin Contamination

    Science.gov (United States)

    Jiang, Tingbo; Zhou, Boru; Luo, Meng; Abbas, Hamed K.; Kemerait, Robert; Lee, Robert Dewey; Scully, Brian T.; Guo, Baozhu

    2011-01-01

    This research examined the expression patterns of 94 stress-related genes in seven maize inbred lines with differential expressions of resistance to aflatoxin contamination. The objective was to develop a set of genes/probes associated with resistance to A. flavus and/or aflatoxin contamination. Ninety four genes were selected from previous gene expression studies with abiotic stress to test the differential expression in maize lines, A638, B73, Lo964, Lo1016, Mo17, Mp313E, and Tex6, using real-time RT-PCR. Based on the relative-expression levels, the seven maize inbred lines clustered into two different groups. One group included B73, Lo1016 and Mo17, which had higher levels of aflatoxin contamination and lower levels of overall gene expression. The second group which included Tex6, Mp313E, Lo964 and A638 had lower levels of aflatoxin contamination and higher overall levels of gene expressions. A total of six “cross-talking” genes were identified between the two groups, which are highly expressed in the resistant Group 2 but down-regulated in susceptible Group 1. When further subjected to drought stress, Tex6 expressed more genes up-regulated and B73 has fewer genes up-regulated. The transcript patterns and interactions measured in these experiments indicate that the resistant mechanism is an interconnected process involving many gene products and transcriptional regulators, as well as various host interactions with environmental factors, particularly, drought and high temperature. PMID:22069724

  1. High-resolution mapping and characterization of qRgls2, a major quantitative trait locus involved in maize resistance to gray leaf spot.

    Science.gov (United States)

    Xu, Ling; Zhang, Yan; Shao, Siquan; Chen, Wei; Tan, Jing; Zhu, Mang; Zhong, Tao; Fan, Xingming; Xu, Mingliang

    2014-08-31

    Gray leaf spot (GLS) caused by Cercospora zeae-maydis (Czm) or Cercospora zeina (Cz) is a devastating maize disease and results in substantial yield reductions worldwide. GLS resistance is a quantitatively inherited trait. The development and cultivation of GLS-resistant maize hybrids are the most cost-effective and efficient ways to control this disease. We previously detected a major GLS resistance QTL, qRgls2, in bin 5.03-04, which spans the whole centromere of chromosome 5 encompassing a physical distance of ~110-Mb. With advanced backcross populations derived from the cross between the resistant Y32 and susceptible Q11 inbred lines, a sequential recombinant-derived progeny testing strategy was adapted to fine map qRgls2. We narrowed the region of qRgls2 from an initial ~110-Mb to an interval of ~1-Mb, flanked by the markers G346 and DD11. qRgls2 showed predominantly additive genetic effects and significantly increased the resistance percentage by 20.6 to 24.6% across multiple generations. A total of 15 genes were predicted in the mapped region according to the 5b.60 annotation of the maize B73 genome v2. Two pieces of the mapped qRgls2 region shared collinearity with two distant segments on maize chromosome 4. qRgls2, a major QTL involved in GLS resistance, was mapped to a ~1-Mb region close to the centromere of chromosome 5. There are 15 predicted genes in the mapped region. It is assumed that qRgls2 could be widely used to improve maize resistance to GLS.

  2. Detection of Genes that Determine Maize Grain Quality Characteristics and Resistance to Stress Factors

    Directory of Open Access Journals (Sweden)

    Markovskyi, O.V.

    2014-01-01

    Full Text Available 200 experimental maize samples (Maize Company were examined for the presence of genes that determine the quality characteristics of grain (wx and fl-2 genes, herbicide (bar (pat, epsps genes and insect (cry-genes resistance. The total DNA was extracted from maize living plant tissue. Primers to detect wx, fl-2, bar (pat, mepsps, CP4 epsps, cry1A(b, cry1F, cry1A.105, mcry3A, cry2Ab2, cry3Bb1, cry34Ab1, cry35Ab1 genes were designed and selected. Multiplex and Touchdown PCR were worked out. PCR amplification of certain sequences was carried out. No transgenes (bar (pat, mepsps, CP4 epsps, cry1A(b, cry1F, cry1A.105, mcry3A, cry2Ab2, cry3Bb1, cry34Ab1, cry35Ab1 were found among 200 analyzed experimental maize samples. At the same time, fl-2 gene was found in 41 samples, wx gene was found in 192 analyzed samples.

  3. Tolerance of Glyphosate-Resistant Maize to Glyphosate Plus MCPA Amine Is Influenced by Dose and Timing

    Directory of Open Access Journals (Sweden)

    Nader Soltani

    2015-01-01

    Full Text Available There is little information on tolerance of glyphosate-resistant maize to glyphosate plus MCPA amine as influenced by dose and timing under Ontario environmental conditions. A total of seven field trials were conducted at various locations in Ontario, Canada, in 2011–2013 to evaluate tolerance of field maize to tank mixes of glyphosate (900 g a.e./ha plus MCPA amine (79, 158, 315, 630, 1260, 2520, or 5040 g a.e./ha at either the 4- or 8-leaf stage. The predicted dose of MCPA amine that caused 5, 10, and 20% injury was 339, 751, and 1914 g a.e./ha when applied to 4-leaf maize but only 64, 140, and 344 g a.e./ha when applied to 8-leaf maize, respectively. The predicted dose of MCPA amine that caused 5, 10, and 20% reduction in shoot dry weight of maize was 488, 844, and 1971 g a.e./ha when applied to 4-leaf maize and only 14, 136, and 616 g a.e./ha when applied to 8-leaf maize, respectively. The predicted dose of MCPA amine that caused 5, 10, and 20% yield reduction was 2557, 4247, and >5040 g a.e./ha when applied to 4-leaf maize and 184, 441, and 1245 g a.e./ha when applied to 8-leaf maize, respectively. Based on these results, glyphosate plus MCPA amine applied at the manufacturer’s recommended dose of 630 g a.e./ha applied to 4-leaf maize has potential to cause injury but the injury is transient with no significant reduction in yield. However, when glyphosate plus MCPA amine is applied to 8-leaf maize it has the potential to cause significant injury and yield loss in maize.

  4. SEED INOCULATION WITH Azospirillum brasilense, ASSOCIATED WITH THE USE OF BIOREGULATORS IN MAIZE

    Directory of Open Access Journals (Sweden)

    ALESSANDRO DE LUCCA E BRACCINI

    2012-01-01

    Full Text Available The inoculation of seeds with the bacterium Azospirillum has been carried out in maize culture and other grasses. The application of growth bio-regulators is another technology whose results in maize culture have yet to become more widespread. Current study evaluates the agronomic effectiveness of seed inoculation with Azospirillum brasilense in maize, associated with the use of the growth regulator Stimulate ®. Triple hybrid maize CD 304 underwent the following treatments: 1 - control without nitrogen and without Azospirillum brasilense; 2 - Treatment without nitrogen but with Azospirillum brasilense; 3 - Treatment without nitrogen but with Azospirillum brasilense + Stimulate ®; 4 - Treatment with 50% of nitrogen dose recommended for maize culture; 5 - Treatment with 50% of nitrogen dose and inoculation with Azospirillum brasilense; 6 - Same as 5 but with Stimulate ®; 7 - Total N recommended; 8 - Total N recommended + Azospirillum brasilense ; 9 - Total N recommended + Azospirillum brasilense + Stimulate ®. The inoculation of maize seeds with Azospirillum brasilense increases plant height and grain yield when compared with rates in control. The use of 50% of N dose in sowing, associated with the inoculation of maize seeds with Azospirillum brasilense at 200 mL ha-1 (mixed to the seeds and associated with Stimulate ® (in foliar application, is viable.

  5. GENETIC DIVERSITY OF S3 MAIZE GENOTYPES RESISTANT TO DOWNY MILDEW BASED ON SSR MARKERS

    Directory of Open Access Journals (Sweden)

    Amran Muis

    2016-02-01

    Full Text Available The compulsory requirement for releasing new high yielding maize varieties is resistance to downy mildew. The study aimed to determine the level of homozygosity, genetic diversity, and  genetic distance of 30 S3 genotypes of maize. Number of primers to be used were 30 polymorphic SSR loci which are distributed over the entire maize genomes. The S3 genotypes used were resistant to downy mildew with homozygosity level of >80%, genetic distance between the test and tester strains >0.7, and anthesis silking interval (ASI between inbred lines and tester lines was maximum 3 days. The results showed that 30 SSR primers used were spread evenly across the maize genomes which were manifested in the representation of SSR loci on each chromosome of a total of 10 chromosomes. The levels of polymorphism ranged from 0.13 to 0.78, an average of 0.51, and the number of alleles ranged from 2 to 8 alleles per SSR locus, an average of 4 alleles per SSR locus. The size of nucleotides in each locus also varied from 70 to 553 bp. Cophenetic correlation value (r at 0.67 indicated that the Unweighted Pair-Group Method Using Arithmetic Averages (UPGMA was less reliable for differentiating genotypes in five groups. Of the total of 30 genotypes analyzed, 17 genotypes had homozygosity level of >80% so it can be included in the hybrid assembly program.

  6. Expression of a maize Myb transcription factor driven by a putative silk-specific promoter significantly enhances resistance to Helicoverpa zea in transgenic maize.

    Science.gov (United States)

    Johnson, Eric T; Berhow, Mark A; Dowd, Patrick F

    2007-04-18

    Hi II maize (Zea mays) plants were engineered to express maize p1 cDNA, a Myb transcription factor, controlled by a putative silk specific promoter, for secondary metabolite production and corn earworm resistance. Transgene expression did not enhance silk color, but about half of the transformed plant silks displayed browning when cut, which indicated the presence of p1-produced secondary metabolites. Levels of maysin, a secondary metabolite with insect toxicity, were highest in newly emerged browning silks. The insect resistance of transgenic silks was also highest at emergence, regardless of maysin levels, which suggests that other unidentified p1-induced molecules likely contributed to larval mortality. Mean survivor weights of corn earworm larvae fed mature browning transgenic silks were significantly lower than weights of those fed mature nonbrowning transgenic silks. Some transgenic pericarps browned with drying and contained similar molecules found in pericarps expressing a dominant p1 allele, suggesting that the promoter may not be silk-specific.

  7. Comparing different maize supplementation strategies to improve resilience and resistance against gastrointestinal nematode infections in browsing goats.

    Science.gov (United States)

    Gárate-Gallardo, Leslie; Torres-Acosta, Juan Felipe de Jesús; Aguilar-Caballero, Armando Jacinto; Sandoval-Castro, Carlos Alfredo; Cámara-Sarmiento, Ramón; Canul-Ku, Hilda Lorena

    2015-01-01

    The effect of maize grain supplementation on the resilience and resistance of browsing Criollo goat kids against gastrointestinal nematodes was evaluated. Five-month-old kids (n = 42), raised worm-free, were allocated to five groups: infected + not supplemented (I-NS; n = 10), infected + maize supplement at 108 g/d (I-S108; n = 8), maize supplement at 1% of body weight (BW) (I-S1%; n = 8), maize supplement at 1.5% BW (I-S1.5%; n = 8), or infected + supplemented (maize supplement 1.5% BW) + moxidectin (0.2 mg/kg BW subcutaneously every 28 d) (T-S1.5%; n = 8). Kids browsed daily (7 h) in a tropical forest for 112 days during the rainy season. Kids were weighed weekly to adjust supplementary feeding. Hematocrit (Ht), hemoglobin (Hb), and eggs per gram of feces were determined fortnightly. On day 112, five goat kids were slaughtered per group to determine worm burdens. Kids of the I-S1.5% group showed similar body-weight change, Ht and Hb, compared to kids without gastrointestinal nematodes (T-S1.5%), as well as lower eggs per gram of feces and Trichostrongylus colubriformis worm burden compared to the I-NS group (P > 0.05). Thus, among the supplement levels tested, increasing maize supplementation at 1.5% BW of kids was the best strategy to improve their resilience and resistance against natural gastrointestinal nematode infections under the conditions of forage from the tropical forest. © L. Gárate-Gallardo et al., published by EDP Sciences, 2015.

  8. Complete sequence and diversity of a maize-associated Polerovirus in East Africa.

    Science.gov (United States)

    Massawe, Deogracious P; Stewart, Lucy R; Kamatenesi, Jovia; Asiimwe, Theodore; Redinbaugh, Margaret G

    2018-06-01

    Since 2011-2012, Maize lethal necrosis (MLN) has emerged in East Africa, causing massive yield loss and propelling research to identify viruses and virus populations present in maize. As expected, next generation sequencing (NGS) has revealed diverse and abundant viruses from the family Potyviridae, primarily sugarcane mosaic virus (SCMV), and maize chlorotic mottle virus (MCMV) (Tombusviridae), which are known to cause MLN by synergistic co-infection. In addition to these expected viruses, we identified a virus in the genus Polerovirus (family Luteoviridae) in 104/172 samples selected for MLN or other potential virus symptoms from Kenya, Uganda, Rwanda, and Tanzania. This polerovirus (MF974579) nucleotide sequence is 97% identical to maize-associated viruses recently reported in China, termed 'maize yellow mosaic virus' (MaYMV) and maize yellow dwarf virus (MaYMV; KU291101, KU291107, MYDV-RMV2; KT992824); and 99% identical to MaYMV (KY684356) infecting sugarcane and itch grass in Nigeria; 83% identical to a barley-associated polerovirus recently identified in Korea (BVG; KT962089); and 79% identical to the U.S. maize-infecting polerovirus maize yellow dwarf virus (MYDV-RMV; KT992824). Nucleotide sequences from ORF0 of 20 individual East African isolates collected from Kenya, Uganda, Rwanda, and Tanzania shared 98% or higher identity, and were detected in 104/172 (60.5%) of samples collected for virus-like symptoms, indicating extensive prevalence but limited diversity of this virus in East Africa. We refer to this virus as "MYDV-like polerovirus" until symptoms of the virus in maize are known.

  9. Anion exchange membrane

    Science.gov (United States)

    Verkade, John G; Wadhwa, Kuldeep; Kong, Xueqian; Schmidt-Rohr, Klaus

    2013-05-07

    An anion exchange membrane and fuel cell incorporating the anion exchange membrane are detailed in which proazaphosphatrane and azaphosphatrane cations are covalently bonded to a sulfonated fluoropolymer support along with anionic counterions. A positive charge is dispersed in the aforementioned cations which are buried in the support to reduce the cation-anion interactions and increase the mobility of hydroxide ions, for example, across the membrane. The anion exchange membrane has the ability to operate at high temperatures and in highly alkaline environments with high conductivity and low resistance.

  10. Association and linkage analysis of aluminum tolerance genes in maize.

    Directory of Open Access Journals (Sweden)

    Allison M Krill

    Full Text Available BACKGROUND: Aluminum (Al toxicity is a major worldwide constraint to crop productivity on acidic soils. Al becomes soluble at low pH, inhibiting root growth and severely reducing yields. Maize is an important staple food and commodity crop in acidic soil regions, especially in South America and Africa where these soils are very common. Al exclusion and intracellular tolerance have been suggested as two important mechanisms for Al tolerance in maize, but little is known about the underlying genetics. METHODOLOGY: An association panel of 282 diverse maize inbred lines and three F2 linkage populations with approximately 200 individuals each were used to study genetic variation in this complex trait. Al tolerance was measured as net root growth in nutrient solution under Al stress, which exhibited a wide range of variation between lines. Comparative and physiological genomics-based approaches were used to select 21 candidate genes for evaluation by association analysis. CONCLUSIONS: Six candidate genes had significant results from association analysis, but only four were confirmed by linkage analysis as putatively contributing to Al tolerance: Zea mays AltSB like (ZmASL, Zea mays aluminum-activated malate transporter2 (ALMT2, S-adenosyl-L-homocysteinase (SAHH, and Malic Enzyme (ME. These four candidate genes are high priority subjects for follow-up biochemical and physiological studies on the mechanisms of Al tolerance in maize. Immediately, elite haplotype-specific molecular markers can be developed for these four genes and used for efficient marker-assisted selection of superior alleles in Al tolerance maize breeding programs.

  11. Maize kernel antioxidants and their potential involvement in Fusarium ear rot resistance.

    Science.gov (United States)

    Picot, Adeline; Atanasova-Pénichon, Vessela; Pons, Sebastien; Marchegay, Gisèle; Barreau, Christian; Pinson-Gadais, Laëtitia; Roucolle, Joël; Daveau, Florie; Caron, Daniel; Richard-Forget, Florence

    2013-04-10

    The potential involvement of antioxidants (α-tocopherol, lutein, zeaxanthin, β-carotene, and ferulic acid) in the resistance of maize varieties to Fusarium ear rot was the focus of this study. These antioxidants were present in all maize kernel stages, indicating that the fumonisin-producing fungi (mainly Fusarium verticillioides and Fusarium proliferatum ) are likely to face them during ear colonization. The effect of these compounds on fumonisin biosynthesis was studied in F. verticillioides liquid cultures. In carotenoid-treated cultures, no inhibitory effect of fumonisin accumulation was observed while a potent inhibitory activity was obtained for sublethal doses of α-tocopherol (0.1 mM) and ferulic acid (1 mM). Using a set of genotypes with moderate to high susceptibility to Fusarium ear rot, ferulic acid was significantly lower in immature kernels of the very susceptible group. Such a relation was nonexistent for tocopherols and carotenoids. Also, ferulic acid in immature kernels ranged from 3 to 8.5 mg/g, i.e., at levels consistent with the in vitro inhibitory concentration. Overall, our data support the fact that ferulic acid may contribute to resistance to Fusarium ear rot and/or fumonisin accumulation.

  12. Evaluation of maize inbred lines for resistance to pre-harvest aflatoxin and fumonisin contamination in the field

    Directory of Open Access Journals (Sweden)

    Baozhu Guo

    2017-06-01

    Full Text Available Two important mycotoxins, aflatoxin and fumonisin, are among the most potent naturally occurring carcinogens, contaminating maize (Zea mays and affecting crop yield and quality. Resistance of maize to pre-harvest mycotoxin contamination, specifically aflatoxin produced by Aspergillus flavus and fumonisin produced by Fusarium verticillioides, is a goal in breeding programs that screen for these important traits with the aim of developing resistant commercial hybrids. We conducted two years of field evaluations on 87 inbred lines originating primarily in China and Mexico and not previously screened for resistance. The objectives of our study were to identify resistant germplasm for breeding purposes and to examine possible relationships between resistances to the two mycotoxins. Aflatoxin and fumonisin were present in samples harvested from all lines in both years. Concentrations of total aflatoxin ranged from 52.00 ± 20.00 to 1524.00 ± 396.00 μg kg−1, while those of fumonisin ranged from 0.60 ± 0.06 to 124.00 ± 19.50 mg kg−1. The inbred lines TUN15, TUN61, TUN37, CY2, and TUN49 showed the lowest aflatoxin accumulation and CN1, GT601, TUN09, TUN61, and MP717 the lowest fumonisin accumulation. TUN61 showed the lowest accumulation of both mycotoxins. This study confirmed previous observations that high levels of aflatoxin can coexist with fumonisin, with 55 maize lines showing a positive correlation coefficient between the concentrations of aflatoxin and fumonisin and 32 lines showing a negative correlation coefficient. These selected lines, particularly TUN61, may provide sources of resistance to mycotoxin contamination in breeding programs. However, the mechanism of resistance in this germplasm remains to be identified. Future research should also address factors that influence the fungus–plant interaction, such as herbivory and environmental stress.

  13. Field-evolved resistance to Bt maize in sugarcane borer (Diatraea saccharalis) in Argentina.

    Science.gov (United States)

    Grimi, Damián A; Parody, Betiana; Ramos, María Laura; Machado, Marcos; Ocampo, Federico; Willse, Alan; Martinelli, Samuel; Head, Graham

    2018-04-01

    Maize technologies expressing Bacillus thuringiensis (Bt) insecticidal proteins are widely used in Argentina to control sugarcane borer (Diatraea saccharalis Fabricius). Unexpected D. saccharalis damage was observed to Bt maize events TC1507 (expressing Cry1F) and MON 89034 × MON 88017 (expressing Cry1A.105 and Cry2Ab2) in an isolated area of San Luis Province. Diatraea saccharalis larvae were sampled from MON 89034 × MON 88017 fields in the area to generate a resistant strain (RR), which was subsequently characterized in plant and diet bioassays. Survivorship of the RR strain was high on TC1507 leaf tissue, intermediate on MON 89034 × MON 88017, and low on MON 810 (expressing Cry1Ab). The RR strain had high resistance to Cry1A.105 (186.74-fold) and no resistance to Cry2Ab2 in diet bioassays. These results indicate resistance to Cry1F and Cry1A.105 (and likely cross-resistance between them) but not to Cry1Ab or Cry2Ab2. Resistance to MON 89034 × MON 88017 was functionally recessive. Reviews of grower records suggest that resistance initially evolved to Cry1F, conferring cross-resistance to Cry1A.105, with low refuge compliance as the primary cause. A mitigation plan was implemented in San Luis that included technology rotation, field monitoring, and grower education on best management practices (BMPs) including refuges. In the affected area, the resistance to Cry1F and Cry1A.105 is being managed effectively through use of MON 89034 × MON 88017 and MON 810 in combination with BMPs, and no spread of resistance to other regions has been observed. © 2017 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. © 2017 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

  14. Genome-wide recombination dynamics are associated with phenotypic variation in maize.

    Science.gov (United States)

    Pan, Qingchun; Li, Lin; Yang, Xiaohong; Tong, Hao; Xu, Shutu; Li, Zhigang; Li, Weiya; Muehlbauer, Gary J; Li, Jiansheng; Yan, Jianbing

    2016-05-01

    Meiotic recombination is a major driver of genetic diversity, species evolution, and agricultural improvement. Thus, an understanding of the genetic recombination landscape across the maize (Zea mays) genome will provide insight and tools for further study of maize evolution and improvement. Here, we used c. 50 000 single nucleotide polymorphisms to precisely map recombination events in 12 artificial maize segregating populations. We observed substantial variation in the recombination frequency and distribution along the ten maize chromosomes among the 12 populations and identified 143 recombination hot regions. Recombination breakpoints were partitioned into intragenic and intergenic events. Interestingly, an increase in the number of genes containing recombination events was accompanied by a decrease in the number of recombination events per gene. This kept the overall number of intragenic recombination events nearly invariable in a given population, suggesting that the recombination variation observed among populations was largely attributed to intergenic recombination. However, significant associations between intragenic recombination events and variation in gene expression and agronomic traits were observed, suggesting potential roles for intragenic recombination in plant phenotypic diversity. Our results provide a comprehensive view of the maize recombination landscape, and show an association between recombination, gene expression and phenotypic variation, which may enhance crop genetic improvement. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  15. Assessing pigmented pericarp of maize kernels as possible source of resistance to fusarium ear rot, Fusarium spp. infection and fumonisin accumulation.

    Science.gov (United States)

    Venturini, Giovanni; Babazadeh, Laleh; Casati, Paola; Pilu, Roberto; Salomoni, Daiana; Toffolatti, Silvia L

    2016-06-16

    One of the purposes of maize genetic improvement is the research of genotypes resistant to fusarium ear rot (FER) and fumonisin accumulation. Flavonoids in the pericarp of the kernels are considered particularly able to reduce the fumonisin accumulation (FUM). The aim of this field study was to assess the effect of flavonoids, associated with anti-insect protection and Fusarium verticillioides inoculation, on FER symptoms and fumonisin contamination in maize kernels. Two isogenic hybrids, one having pigmentation in the pericarp (P1-rr) and the other without it (P1-wr), were compared. P1-rr showed lower values of FER symptoms and FUM contamination than P1-wr only if the anti-insect protection and the F. verticillioides inoculations were applied in combination. Fusarium spp. kernel infection was not influenced by the presence of flavonoids in the pericarp. Artificial F. verticillioides inoculation was more effective than anti-insect protection in enhancing the inhibition activity of flavonoids toward FUM contamination. The interactions between FUM contamination levels and FER ratings were better modeled in the pigmented hybrid than in the unpigmented one. The variable role that the pigment played in kernel defense against FER and FUM indicates that flavonoids alone may not be completely effective in the resistance of fumonisin contamination in maize. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Design and fabrication of enhanced corrosion resistance Zn-Al layered double hydroxides films based anion-exchange mechanism on magnesium alloys

    Science.gov (United States)

    Zhou, Meng; Yan, Luchun; Ling, Hao; Diao, Yupeng; Pang, Xiaolu; Wang, Yanlin; Gao, Kewei

    2017-05-01

    Layered double hydroxides (LDHs) with brucite-like layer structure and the facile exchangeability of intercalated anions had attracted tremendous interest in many fields because of their great importance for both fundamental studies and practical applications. Herein zinc-aluminum layered double hydroxides (Zn-Al LDHs) films intercalated with nitrate anions on the magnesium alloy substrate were designed and fabricated via a facile hydrothermal crystallization method. In order to obtain better corrosion resistance, chloride and vanadate anions were intercalated into the LDHs interlayers via the anion-exchange reaction. X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy and scanning electronic microscopy (SEM) were used to examine structure, composition and morphology of the Zn-Al-NO3 LDHs, Zn-Al-Cl LDHs and Zn-Al-VOx LDHs films. The corrosion resistance of the Zn-Al LDHs with different anion films was estimated by the electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization measurement. EIS and polarization curves measurements revealed that the magnesium alloy could be effectively protected by the Zn-Al-Cl LDHs and Zn-Al-VOx LDHs films due to the blocking effect of chloride anions and the control-release ability of vanadate anions.

  17. Resistance to Aspergillus flavus in maize and peanut: Molecular biology, breeding, environmental stress, and future perspectives

    Directory of Open Access Journals (Sweden)

    Jake C. Fountain

    2015-06-01

    Full Text Available The colonization of maize (Zea mays L. and peanut (Arachis hypogaea L. by the fungal pathogen Aspergillus flavus results in the contamination of kernels with carcinogenic mycotoxins known as aflatoxins leading to economic losses and potential health threats to humans. The regulation of aflatoxin biosynthesis in various Aspergillus spp. has been extensively studied, and has been shown to be related to oxidative stress responses. Given that environmental stresses such as drought and heat stress result in the accumulation of reactive oxygen species (ROS within host plant tissues, host-derived ROS may play an important role in cross-kingdom communication between host plants and A. flavus. Recent technological advances in plant breeding have provided the tools necessary to study and apply knowledge derived from metabolomic, proteomic, and transcriptomic studies in the context of productive breeding populations. Here, we review the current understanding of the potential roles of environmental stress, ROS, and aflatoxin in the interaction between A. flavus and its host plants, and the current status in molecular breeding and marker discovery for resistance to A. flavus colonization and aflatoxin contamination in maize and peanut. We will also propose future directions and a working model for continuing research efforts linking environmental stress tolerance and aflatoxin contamination resistance in maize and peanut.

  18. Overlapping Residual Herbicides for Control of Photosystem (PS) II- and 4-Hydroxyphenylpyruvate Dioxygenase (HPPD)-Inhibitor-Resistant Palmer amaranth (Amaranthus palmeri S. Watson) in Glyphosate-Resistant Maize

    Science.gov (United States)

    Chahal, Parminder S.; Ganie, Zahoor A.; Jhala, Amit J.

    2018-01-01

    A Palmer amaranth (Amaranthus palmeri S. Watson) biotype has evolved resistance to photosystem (PS) II- (atrazine) and 4-hydroxyphenylpyruvate dioxygenase (HPPD)-inhibiting herbicides (mesotrione, tembotrione, and topramezone) in maize seed production field in Nebraska, USA. The objectives of this study were to determine the effect of soil residual pre-emergence (PRE) herbicides followed by (fb) tank-mixture of residual and foliar active post-emergence (POST) herbicides on PS-II- and HPPD-inhibitor-resistant Palmer amaranth control, maize yield, and net economic returns. Field experiments were conducted in a grower's field infested with PS II- and HPPD-inhibitor-resistant Palmer amaranth near Shickley in Fillmore County, Nebraska, USA in 2015 and 2016. The contrast analysis suggested that saflufenacil plus dimethenamid-P or pyroxasulfone plus saflufenacil applied PRE provided 80–82% Palmer amaranth control compared to 65 and 39% control with saflufenacil and pyroxasulfone applied alone at 3 weeks after PRE (WAPRE), respectively. Among the PRE fb POST herbicide programs, 95–98% Palmer amaranth control was achieved with pyroxasulfone plus safluefenacil, or saflufenacil plus dimethenamid-P applied PRE, fb glyphosate plus topramezone plus dimethenamid-P plus atrazine, glyphosate plus diflufenzopyr plus dicamba plus pyroxasulfone, glyphosate plus diflufenzopyr plus pendimethalin, or glyphosate plus diflufenzopyr plus dicamba plus atrazine applied POST at 3 weeks after POST (WAPOST) through maize harvest. Based on contrast analysis, PRE fb POST programs provided 77–83% Palmer amaranth control at 3 WAPOST through maize harvest compared to 12–15% control with PRE-only and 66–84% control with POST-only programs. Similarly, PRE fb POST programs provided 99% biomass reduction at 6 WAPOST compared to PRE-only (28%) and POST-only (87%) programs. PRE fb POST programs provided higher maize yield (13,617 kg ha−1) and net return (US $1,724 ha−1) compared to the PRE

  19. Production of a Highly Protease-Resistant Fungal α-Galactosidase in Transgenic Maize Seeds for Simplified Feed Processing.

    Science.gov (United States)

    Yang, Wenxia; Zhang, Yuhong; Zhou, Xiaojin; Zhang, Wei; Xu, Xiaolu; Chen, Rumei; Meng, Qingchang; Yuan, Jianhua; Yang, Peilong; Yao, Bin

    2015-01-01

    Raffinose-family oligosaccharide (RFO) in soybeans is one of the major anti-nutritional factors for poultry and livestocks. α-Galactosidase is commonly supplemented into the animal feed to hydrolyze α-1,6-galactosidic bonds on the RFOs. To simplify the feed processing, a protease-resistant α-galactosidase encoding gene from Gibberella sp. strain F75, aga-F75, was modified by codon optimization and heterologously expressed in the embryos of transgentic maize driven by the embryo-specific promoter ZM-leg1A. The progenies were produced by backcrossing with the commercial inbred variety Zheng58. PCR, southern blot and western blot analysis confirmed the stable integration and tissue specific expression of the modified gene, aga-F75m, in seeds over four generations. The expression level of Aga-F75M reached up to 10,000 units per kilogram of maize seeds. In comparison with its counterpart produced in Pichia pastoris strain GS115, maize seed-derived Aga-F75M showed a lower temperature optimum (50 °C) and lower stability over alkaline pH range, but better thermal stability at 60 °C to 70 °C and resistance to feed pelleting inactivation (80 °C). This is the first report of producing α-galactosidase in transgenic plant. The study offers an effective and economic approach for direct utilization of α-galactosidase-producing maize without any purification or supplementation procedures in the feed processing.

  20. How are arbuscular mycorrhizal associations related to maize growth performance during short-term cover crop rotation?

    Science.gov (United States)

    Higo, Masao; Takahashi, Yuichi; Gunji, Kento; Isobe, Katsunori

    2018-03-01

    Better cover crop management options aiming to maximize the benefits of arbuscular mycorrhizal fungi (AMF) to subsequent crops are largely unknown. We investigated the impact of cover crop management methods on maize growth performance and assemblages of AMF colonizing maize roots in a field trial. The cover crop treatments comprised Italian ryegrass, wheat, brown mustard and fallow in rotation with maize. The diversity of AMF communities among cover crops used for maize management was significantly influenced by the cover crop and time course. Cover crops did not affect grain yield and aboveground biomass of subsequent maize but affected early growth. A structural equation model indicated that the root colonization, AMF diversity and maize phosphorus uptake had direct strong positive effects on yield performance. AMF variables and maize performance were related directly or indirectly to maize grain yield, whereas root colonization had a positive effect on maize performance. AMF may be an essential factor that determines the success of cover crop rotational systems. Encouraging AMF associations can potentially benefit cover cropping systems. Therefore, it is imperative to consider AMF associations and crop phenology when making management decisions. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  1. Comparison of grain from corn rootworm resistant transgenic DAS-59122-7 maize with non-transgenic maize grain in a 90-day feeding study in Sprague-Dawley rats.

    Science.gov (United States)

    He, X Y; Huang, K L; Li, X; Qin, W; Delaney, B; Luo, Y B

    2008-06-01

    DAS-59122-7 (59122) is a transgenic maize (Zea mays L.) that contains genes encoding Cry34Ab1 and Cry35Ab1 proteins from Bacillus thuringiensis Berliner strain 149B1 and phosphinothricin acetyltransferase (PAT) protein from Streptomyces viridochromogenes. Expression of these proteins in planta confers resistance to corn rootworms and other Coleopteran parasites and tolerance to herbicides containing glufosinate ammonium, respectively. In the current study, processed flours from 59122 maize grain or its near isogenic control line (091) were used at two concentrations (50% and 70% wt/wt) to produce diets that were fed to rats for 90 days in accordance with Chinese toxicology guidelines (GB15193.13-2003). A commercial AIN93G diet was used as an additional negative control. No significant differences in body weight and feed utilization were observed between rats consuming diets formulated with 59122 and 091 Control corn. Statistical differences (p<0.05) were observed in certain hematology and serum chemistry response variables between rats consuming diets formulated with 59122 or 091 Control flour compared to AIN93G diet. However, the mean value of these response variables in the 59122 groups were not statistically different from those observed in diets formulated with corresponding high and low concentrations of the flour from the 091 Control maize grain. Therefore, the statistical differences were considered to be related to consumption of diets containing high concentrations of maize flour (compared to AIN93G diets) regardless of source rather than to consumption of flour from 59122 maize grain. The results from this study demonstrated that 59122 maize grain is as safe as non-transgenic maize grain.

  2. Determination of the Heterotic groups of Maize inbred lines and the ...

    African Journals Online (AJOL)

    Maize weevil (Sitophilus zeamais Motschulsky) is a major maize (Zea mays L) storage insect pest in the tropics. Fifty-two inbred lines developed for weevil resistance were crossed to two testers, A and B, to determine their heterotic groups and inheritance of resistance to maize weevil. For 10 testcrosses selected for ...

  3. Resistance to Fusarium verticillioides and fumonisin accumulation in maize inbred lines involves an earlier and enhanced expression of lipoxygenase (LOX) genes.

    Science.gov (United States)

    Maschietto, Valentina; Marocco, Adriano; Malachova, Alexandra; Lanubile, Alessandra

    2015-09-01

    Fusarium verticillioides causes ear rot in maize and contaminates the kernels with the fumonisin mycotoxins. It is known that plant lipoxygenase (LOX)-derived oxylipins regulate defence against pathogens and that the host-pathogen lipid cross-talk influences the pathogenesis. The expression profiles of fifteen genes of the LOX pathway were studied in kernels of resistant and susceptible maize lines, grown in field condition, at 3, 7 and 14 days post inoculation (dpi) with F. verticillioides. Plant defence responses were correlated with the pathogen growth, the expression profiles of fungal FUM genes for fumonisin biosynthesis and fumonisin content in the kernels. The resistant genotype limited fungal growth and fumonisin accumulation between 7 and 14 dpi. Pathogen growth became exponential in the susceptible line after 7 dpi, in correspondence with massive transcription of FUM genes and fumonisins augmented exponentially at 14 dpi. LOX pathway genes resulted strongly induced after pathogen inoculation in the resistant line at 3 and 7 dpi, whilst in the susceptible line the induction was reduced or delayed at 14 dpi. In addition, all genes resulted overexpressed before infection in kernels of the resistant genotype already at 3 dpi. The results suggest that resistance in maize may depend on an earlier activation of LOX genes and genes for jasmonic acid biosynthesis. Copyright © 2015 Elsevier GmbH. All rights reserved.

  4. Design and fabrication of enhanced corrosion resistance Zn-Al layered double hydroxides films based anion-exchange mechanism on magnesium alloys

    International Nuclear Information System (INIS)

    Zhou, Meng; Yan, Luchun; Ling, Hao; Diao, Yupeng; Pang, Xiaolu; Wang, Yanlin; Gao, Kewei

    2017-01-01

    Highlights: • Zn-Al LDHs film loaded nitrate anions has been fabricated on a magnesium alloy substrate via a facile hydrothermal crystallization method. • The Zn-Al-Cl LDHs and Zn-Al-VO_x LDHs film were obtained based on anion-exchange mechanism. • The Zn-Al-Cl LDHs and Zn-Al-VO_x LDHs film could effectively protect magnesium alloy. - Abstract: Layered double hydroxides (LDHs) with brucite-like layer structure and the facile exchangeability of intercalated anions had attracted tremendous interest in many fields because of their great importance for both fundamental studies and practical applications. Herein zinc-aluminum layered double hydroxides (Zn-Al LDHs) films intercalated with nitrate anions on the magnesium alloy substrate were designed and fabricated via a facile hydrothermal crystallization method. In order to obtain better corrosion resistance, chloride and vanadate anions were intercalated into the LDHs interlayers via the anion-exchange reaction. X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy and scanning electronic microscopy (SEM) were used to examine structure, composition and morphology of the Zn-Al-NO_3 LDHs, Zn-Al-Cl LDHs and Zn-Al-VO_x LDHs films. The corrosion resistance of the Zn-Al LDHs with different anion films was estimated by the electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization measurement. EIS and polarization curves measurements revealed that the magnesium alloy could be effectively protected by the Zn-Al-Cl LDHs and Zn-Al-VO_x LDHs films due to the blocking effect of chloride anions and the control-release ability of vanadate anions.

  5. Design and fabrication of enhanced corrosion resistance Zn-Al layered double hydroxides films based anion-exchange mechanism on magnesium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Meng; Yan, Luchun; Ling, Hao; Diao, Yupeng; Pang, Xiaolu; Wang, Yanlin; Gao, Kewei, E-mail: kwgao@yahoo.com

    2017-05-15

    Highlights: • Zn-Al LDHs film loaded nitrate anions has been fabricated on a magnesium alloy substrate via a facile hydrothermal crystallization method. • The Zn-Al-Cl LDHs and Zn-Al-VO{sub x} LDHs film were obtained based on anion-exchange mechanism. • The Zn-Al-Cl LDHs and Zn-Al-VO{sub x} LDHs film could effectively protect magnesium alloy. - Abstract: Layered double hydroxides (LDHs) with brucite-like layer structure and the facile exchangeability of intercalated anions had attracted tremendous interest in many fields because of their great importance for both fundamental studies and practical applications. Herein zinc-aluminum layered double hydroxides (Zn-Al LDHs) films intercalated with nitrate anions on the magnesium alloy substrate were designed and fabricated via a facile hydrothermal crystallization method. In order to obtain better corrosion resistance, chloride and vanadate anions were intercalated into the LDHs interlayers via the anion-exchange reaction. X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy and scanning electronic microscopy (SEM) were used to examine structure, composition and morphology of the Zn-Al-NO{sub 3} LDHs, Zn-Al-Cl LDHs and Zn-Al-VO{sub x} LDHs films. The corrosion resistance of the Zn-Al LDHs with different anion films was estimated by the electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization measurement. EIS and polarization curves measurements revealed that the magnesium alloy could be effectively protected by the Zn-Al-Cl LDHs and Zn-Al-VO{sub x} LDHs films due to the blocking effect of chloride anions and the control-release ability of vanadate anions.

  6. Quantitative trait loci for resistance to Maize rayado fino virus

    Science.gov (United States)

    Maize rayado fino virus (MRFV) causes one of the most important virus diseases of maize in regions of Mexico, Central and South America, where it causes moderate to severe yield losses. The virus is found from the southern United States. to northern Argentina where its vector, the maize leafhopper D...

  7. Grain Yield and Fusarium Ear Rot of Maize Hybrids Developed From Lines With Varying Levels of Resistance

    Science.gov (United States)

    Fusarium ear rot, caused by Fusarium verticillioides and other Fusarium spp. is found in all U.S. maize growing regions. Affected grain often contains carcinogenic mycotoxins called fumonisins. We tested the hypothesis that inbred lines with greater resistance to fumonisin contamination would pro...

  8. Genome-wide association study identifies candidate genes for starch content regulation in maize kernels

    Directory of Open Access Journals (Sweden)

    Na Liu

    2016-07-01

    Full Text Available Kernel starch content is an important trait in maize (Zea mays L. as it accounts for 65% to 75% of the dry kernel weight and positively correlates with seed yield. A number of starch synthesis-related genes have been identified in maize in recent years. However, many loci underlying variation in starch content among maize inbred lines still remain to be identified. The current study is a genome-wide association study that used a set of 263 maize inbred lines. In this panel, the average kernel starch content was 66.99%, ranging from 60.60% to 71.58% over the three study years. These inbred lines were genotyped with the SNP50 BeadChip maize array, which is comprised of 56,110 evenly spaced, random SNPs. Population structure was controlled by a mixed linear model (MLM as implemented in the software package TASSEL. After the statistical analyses, four SNPs were identified as significantly associated with starch content (P ≤ 0.0001, among which one each are located on chromosomes 1 and 5 and two are on chromosome 2. Furthermore, 77 candidate genes associated with starch synthesis were found within the 100-kb intervals containing these four QTLs, and four highly associated genes were within 20-kb intervals of the associated SNPs. Among the four genes, Glucose-1-phosphate adenylyltransferase (APS1; Gene ID GRMZM2G163437 is known as an important regulator of kernel starch content. The identified SNPs, QTLs, and candidate genes may not only be readily used for germplasm improvement by marker-assisted selection in breeding, but can also elucidate the genetic basis of starch content. Further studies on these identified candidate genes may help determine the molecular mechanisms regulating kernel starch content in maize and other important cereal crops.

  9. Proteomic analysis of the maize rachis: potential roles of constitutive and induced proteins in resistance to Aspergillus flavus infection and aflatoxin accumulation.

    Science.gov (United States)

    Pechanova, Olga; Pechan, Tibor; Williams, W Paul; Luthe, Dawn S

    2011-01-01

    Infection of the maize (Zea mays L.) with aflatoxigenic fungus Aspergillus flavus and consequent contamination with carcinogenic aflatoxin is a persistent and serious agricultural problem causing disease and significant crop losses worldwide. The rachis (cob) is an important structure of maize ear that delivers essential nutrients to the developing kernels and A. flavus spreads through the rachis to infect kernels within the ear. Therefore, rachis plays an important role in fungal proliferation and subsequent kernel contamination. We used proteomic approaches and investigated the rachis tissue from aflatoxin accumulation resistant (Mp313E and Mp420) and susceptible (B73 and SC212m) maize inbred lines. First, we compared rachis proteins from resistant and susceptible inbred lines, which revealed that the young resistant rachis contains higher levels of abiotic stress-related proteins and proteins from phenylpropanoid metabolism, whereas susceptible young rachis contains pathogenesis-related proteins, which are generally inducible upon biotic stress. Second, we identified A. flavus-responsive proteins in rachis of both resistant and susceptible genotypes after 10- and 35-day infection. Differential expression of many stress/defense proteins during rachis juvenility, maturation and after A. flavus challenge demonstrates that resistant rachis relies on constitutive defenses, while susceptible rachis is more dependent on inducible defenses. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Leaf transpiration efficiency of some drought-resistant maize lines

    Science.gov (United States)

    Field measurements of leaf gas exchange in maize often indicate stomatal conductances higher than required to provide substomatal carbon dioxide concentrations saturating to photosynthesis. Thus maize leaves often operate at lower transpiration efficiency (TE) than potentially achievable for specie...

  11. A review on threat of gray leaf spot disease of maize in Asia

    Directory of Open Access Journals (Sweden)

    Narayan Bahadur Dhami

    2015-12-01

    Full Text Available Biotic and biotic constraints are yield limiting factors in maize producing regions. Among these gray leaf spot is a yield limiting foliar disease of maize in high land regions of Asia. This review is done from related different national and international journals, thesis, books, research papers etc. The objectives of this review are to become familiar with genetics and inheritance, epidemiology, symptoms and disease management strategies etc. High relative humidity, temperature, minimum tillage and maize monoculture are important factors responsible for disease development. The sibling species of Cercospora zeae-maydis (Tehon and Daniels, 1925 Group I and Group II and Cercospora sorghai var. maydis (Chupp, 1954 are associated with this disease. Pathogens colonize in maize debris. Conidia are the source of inoculums for disease spread. Severe blighting of leaves reduces sugars, stalk lodging and causes premature death of plants resulting in yield losses of up to 100%. Disease management through cultural practices is provisional. The use of fungicides for emergencies is effective however; their prohibitive cost and detrimental effects on the environment are negative consequences. The inheritance of tolerance is quantitative with small additive effects. The introgression of resistant genes among the crosses of resistant germplasm enhances the resistance. The crosses of resistant and susceptible germplasm possess greater stability than the crosses of susceptible and resistant germplasm. The development of gray leaf spot tolerant populations through tolerance breeding principle is an economical and sustainable approach to manage the disease.

  12. Life-History Traits of Spodoptera frugiperda Populations Exposed to Low-Dose Bt Maize.

    Science.gov (United States)

    Sousa, Fernanda F; Mendes, Simone M; Santos-Amaya, Oscar F; Araújo, Octávio G; Oliveira, Eugenio E; Pereira, Eliseu J G

    2016-01-01

    Exposure to Bacillus thuringiensis (Bt) toxins in low- and moderate-dose transgenic crops may induce sublethal effects and increase the rate of Bt resistance evolution, potentially compromising control efficacy against target pests. We tested this hypothesis using the fall armyworm Spodoptera frugiperda, a major polyphagous lepidopteran pest relatively tolerant to Bt notorious for evolving field-relevant resistance to single-gene Bt maize. Late-instar larvae were collected from Bt Cry1Ab and non-Bt maize fields in five locations in Brazil, and their offspring was compared for survival, development, and population growth in rearing environment without and with Cry1Ab throughout larval development. Larval survival on Cry1Ab maize leaves varied from 20 to 80% among the populations. Larvae reared on Cry1Ab maize had seven-day delay in development time in relation to control larvae, and such delay was shorter in offspring of armyworms from Cry1Ab maize. Population growth rates were 50-70% lower for insects continuously exposed to Cry1Ab maize relative to controls, showing the population-level effect of Cry1Ab, which varied among the populations and prior exposure to Cry1Ab maize in the field. In three out of five populations, armyworms derived from Bt maize reared on Cry1Ab maize showed higher larval weight, faster larval development and better reproductive performance than the armyworms derived from non-Bt maize, and one of these populations showed better performance on both Cry1Ab and control diets, indicating no fitness cost of the resistance trait. Altogether, these results indicate that offspring of armyworms that developed on field-grown, single-gene Bt Cry1Ab maize had reduced performance on Cry1Ab maize foliage in two populations studied, but in other three populations, these offspring had better overall performance on the Bt maize foliage than that of the armyworms from non-Bt maize fields, possibly because of Cry1Ab resistance alleles in these populations

  13. F2 screen for resistance to Bacillus thuringiensis Cry2Ab2-maize in field populations of Spodoptera frugiperda (Lepidoptera: Noctuidae) from the southern United States.

    Science.gov (United States)

    Niu, Ying; Qureshi, Jawwad A; Ni, Xinzhi; Head, Graham P; Price, Paula A; Meagher, Robert L; Kerns, David; Levy, Ronnie; Yang, Xiangbing; Huang, Fangneng

    2016-07-01

    The fall armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), is a target pest of transgenic maize and cotton expressing Bacillus thuringiensis (Bt) proteins in both North and South America. In 2013 and 2014, a total of 215 F2 two-parent families of S. frugiperda were established using single-pair mating of field individuals collected from seven locations in four states of the southern U.S.: Texas, Louisiana, Georgia, and Florida. The objective of the investigation was to detect resistance alleles in field populations to Cry2Ab2, a common Bt protein produced in transgenic maize and cotton. For each F2 family, 128 F2 neonates were screened on leaf tissue of Cry2Ab2 maize plants in the laboratory. A conservative estimate of the frequency of major Cry2Ab2 resistance alleles in S. frugiperda from the four states was 0.0023 with a 95% credibility interval of 0.0003-0.0064. In addition, six families were considered to likely possess minor resistance alleles at a frequency of 0.0082 with a 95% credibility interval of 0.0033-0.0152. One F2 family from Georgia (GA-15) was confirmed to possess a major resistance allele to the Cry2Ab2 protein. Larvae from this family survived well on whole maize plants expressing Cry2Ab2 protein and demonstrated a significant level (>15-fold) of resistance when fed with the same protein incorporated in a meridic diet. The detection of the major resistance allele along with the relatively abundant minor resistance alleles revealed in this study may have important implications for resistance management. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. Comparative Histological and Transcriptional Analysis of Maize Kernels Infected with Aspergillus flavus and Fusarium verticillioides

    Directory of Open Access Journals (Sweden)

    Xiaomei Shu

    2017-12-01

    Full Text Available Aspergillus flavus and Fusarium verticillioides infect maize kernels and contaminate them with the mycotoxins aflatoxin, and fumonisin, respectively. Genetic resistance in maize to these fungi and to mycotoxin contamination has been difficult to achieve due to lack of identified resistance genes. The objective of this study was to identify new candidate resistance genes by characterizing their temporal expression in response to infection and comparing expression of these genes with genes known to be associated with plant defense. Fungal colonization and transcriptional changes in kernels inoculated with each fungus were monitored at 4, 12, 24, 48, and 72 h post inoculation (hpi. Maize kernels responded by differential gene expression to each fungus within 4 hpi, before the fungi could be observed visually, but more genes were differentially expressed between 48 and 72 hpi, when fungal colonization was more extensive. Two-way hierarchal clustering analysis grouped the temporal expression profiles of the 5,863 differentially expressed maize genes over all time points into 12 clusters. Many clusters were enriched for genes previously associated with defense responses to either A. flavus or F. verticillioides. Also within these expression clusters were genes that lacked either annotation or assignment to functional categories. This study provided a comprehensive analysis of gene expression of each A. flavus and F. verticillioides during infection of maize kernels, it identified genes expressed early and late in the infection process, and it provided a grouping of genes of unknown function with similarly expressed defense related genes that could inform selection of new genes as targets in breeding strategies.

  15. Evaluation of Maize Germplasm for Resistance to Aflatoxin Accumulation

    Directory of Open Access Journals (Sweden)

    Michael H. Blanco

    2012-03-01

    Full Text Available Aflatoxin contamination of maize grain threatens human food and animal feed safety. Breeding for reduced grain aflatoxin accumulation is one of the best strategies presently available to lower grain aflatoxin accumulation. Previously identified sources of germplasm with reduced grain aflatoxin accumulation are excessively tall and late maturing. The objective of this research was to screen germplasm and identify potential sources of aflatoxin resistance. KO679Y and CUBA117:S15-101-001-B-B-B-B inbreds were evaluated for aflatoxin accumulation alongside resistant and susceptible checks with both performing well. These two lines were also evaluated in various crosses. KO679Y performed especially well in crosses with Mp494 and Mp717, resulting in low ear rot and very low aflatoxin levels, but not well in other crosses. A breeding cross including CUBA117:S15-101-001-B-B-B-B as a parent accumulated low levels of aflatoxin both years it was evaluated. Lines resulting from these crosses are being advanced for further evaluation and improvement. KO679Y and CUBA117:S15-101-001-B-B-B-B may prove useful for breeders seeking germplasm sources for ear rot and mycotoxin reduction, especially KO679Y which matures a week earlier and is approximately 25% shorter than current lines resistant to grain aflatoxin accumulation.

  16. Genetic markers for western corn rootworm resistance to Bt toxin.

    Science.gov (United States)

    Flagel, Lex E; Swarup, Shilpa; Chen, Mao; Bauer, Christopher; Wanjugi, Humphrey; Carroll, Matthew; Hill, Patrick; Tuscan, Meghan; Bansal, Raman; Flannagan, Ronald; Clark, Thomas L; Michel, Andrew P; Head, Graham P; Goldman, Barry S

    2015-01-07

    Western corn rootworm (WCR) is a major maize (Zea mays L.) pest leading to annual economic losses of more than 1 billion dollars in the United States. Transgenic maize expressing insecticidal toxins derived from the bacterium Bacillus thuringiensis (Bt) are widely used for the management of WCR. However, cultivation of Bt-expressing maize places intense selection pressure on pest populations to evolve resistance. Instances of resistance to Bt toxins have been reported in WCR. Developing genetic markers for resistance will help in characterizing the extent of existing issues, predicting where future field failures may occur, improving insect resistance management strategies, and in designing and sustainably implementing forthcoming WCR control products. Here, we discover and validate genetic markers in WCR that are associated with resistance to the Cry3Bb1 Bt toxin. A field-derived WCR population known to be resistant to the Cry3Bb1 Bt toxin was used to generate a genetic map and to identify a genomic region associated with Cry3Bb1 resistance. Our results indicate that resistance is inherited in a nearly recessive manner and associated with a single autosomal linkage group. Markers tightly linked with resistance were validated using WCR populations collected from Cry3Bb1 maize fields showing significant WCR damage from across the US Corn Belt. Two markers were found to be correlated with both diet (R2 = 0.14) and plant (R2 = 0.23) bioassays for resistance. These results will assist in assessing resistance risk for different WCR populations, and can be used to improve insect resistance management strategies. Copyright © 2015 Flagel et al.

  17. The Combining Ability of Maize Inbred Lines for Grain Yield and ...

    African Journals Online (AJOL)

    The Combining Ability of Maize Inbred Lines for Grain Yield and Reaction to Grey ... East African Journal of Sciences ... (GLS) to maize production, the national maize research program of Ethiopia ... The information from this study will be useful for the development of high-yielding and GLS disease-resistant maize varieties.

  18. Review: Maize research and production in Nigeria | Iken | African ...

    African Journals Online (AJOL)

    Maize (Zea mays) is a major important cereal being cultivated in the rainforest and the derived Savannah zones of Nigeria. Land races, improved high yielding and pest and diseases resistant varieties of maize have been developed. Key words: Maize, Zea mays, Nigeria. African Journal of Biotechnology Vol.3(6) 2004: 302- ...

  19. Effect of root temperature on the uptake and metabolism of anions by the root system of Zea mays L. I. Uptake of sulphate by resistant and non-resistant plants

    Energy Technology Data Exchange (ETDEWEB)

    Holobrada, M; Mistrik, I; Kolek, J [Institute of Experimental Biology and Ecology of the Slovak Academy of Sciences, Bratislava (Czechoslovakia)

    1980-01-01

    The effect of root temperature upon the uptake of /sup 35/S-sulfate by intact 21 days old maize roots was discussed. The plant roots grown at 20 degC were cooled in steps down to 15 degC or 5 degC. The rate of /sup 35/S uptake was studied both in the whole root system and separately in the individual roots (primary seminal root, seminal adventitious roots and nodal roots). Differences were ascertained at lower uptakes by various root samples from resistant and nonresistant maize cultivars.

  20. Double mutation in eleusine indica alpha-tubulin increases the resistance of transgenic maize calli to dinitroaniline and phosphorothioamidate herbicides

    Science.gov (United States)

    Anthony; Hussey

    1999-06-01

    The repeated use of dinitroaniline herbicides on the cotton and soybean fields of the southern United States has resulted in the appearance of resistant biotypes of one of the world's worst weeds, Eleusine indica. Two biotypes have been characterized, a highly resistant (R) biotype and an intermediate resistant (I) biotype. In both cases the resistance has been attributed to a mutation in alpha-tubulin, a component of the alpha/beta tubulin dimer that is the major constituent of microtubules. We show here that the I-biotype mutation, like the R-biotype mutation shown in earlier work, can confer dinitroaniline resistance on transgenic maize calli. The level of resistance obtained is the same as that for E. indica I- or R-biotype seedlings. The combined I- and R-biotype mutations increase the herbicide tolerance of transgenic maize calli by a value close to the summation of the maximum herbicide tolerances of calli harbouring the single mutations. These data, taken together with the position of the two different mutations within the atomic structure of the alpha/beta tubulin dimer, imply that each mutation is likely to exert its effect by a different mechanism. These mechanisms may involve increasing the stability of microtubules against the depolymerizing effects of the herbicide or changing the conformation of the alpha/beta dimer so that herbicide binding is less effective, or a combination of both possibilities.

  1. A Technique for Identification of Intrinsic Resistance of Maize ...

    African Journals Online (AJOL)

    ... the insect fat body to determine the levels of fat body vitellogenin (FVg) in the vitellogenic S. zeamais females which were reared on different maize varieties. Results on levels of FVg varied and ranged from 83.33% to 43.33% in insects raised in different varieties ANOVA of FVg, maize weight loss and F1 numbers showed ...

  2. Cellulase from Trichoderma harzianum interacts with roots and triggers induced systemic resistance to foliar disease in maize

    Science.gov (United States)

    Saravanakumar, Kandasamy; Fan, Lili; Fu, Kehe; Yu, Chuanjin; Wang, Meng; Xia, Hai; Sun, Jianan; Li, Yaqian; Chen, Jie

    2016-01-01

    Trichoderma harzianum is well known to exhibit induced systemic resistance (ISR) to Curvularia leaf spot. We previously reported that a C6 zinc finger protein (Thc6) is responsible for a major contribution to the ISR to the leaf disease, but the types of effectors and the signals mediated by Thc6 from Trichoderma are unclear. In this work, we demonstrated that two hydrolases, Thph1 and Thph2, from T. harzianum were regulated by Thc6. Furthermore, an electrophoretic mobility shift assay (EMSA) study revealed that Thc6 regulated mRNA expression by binding to GGCTAA and GGCTAAA in the promoters of the Thph1 and Thph2 genes, respectively. Moreover, the Thph1 and Thph2 proteins triggered the transient production of reactive oxygen species (ROS) and elevated the free cytosolic calcium levels in maize leaf. Furthermore, the genes related to the jasmonate/ethylene signaling pathway were up-regulated in the wild-type maize strain. However, the ΔThph1- or ΔThph2-deletion mutants could not activate the immune defense-related genes in maize to protect against leaf disease. Therefore, we conclude that functional Thph1 and Thph2 may be required in T. harzianum to activate ISR in maize. PMID:27830829

  3. Cellulase from Trichoderma harzianum interacts with roots and triggers induced systemic resistance to foliar disease in maize.

    Science.gov (United States)

    Saravanakumar, Kandasamy; Fan, Lili; Fu, Kehe; Yu, Chuanjin; Wang, Meng; Xia, Hai; Sun, Jianan; Li, Yaqian; Chen, Jie

    2016-11-10

    Trichoderma harzianum is well known to exhibit induced systemic resistance (ISR) to Curvularia leaf spot. We previously reported that a C6 zinc finger protein (Thc6) is responsible for a major contribution to the ISR to the leaf disease, but the types of effectors and the signals mediated by Thc6 from Trichoderma are unclear. In this work, we demonstrated that two hydrolases, Thph1 and Thph2, from T. harzianum were regulated by Thc6. Furthermore, an electrophoretic mobility shift assay (EMSA) study revealed that Thc6 regulated mRNA expression by binding to GGCTAA and GGCTAAA in the promoters of the Thph1 and Thph2 genes, respectively. Moreover, the Thph1 and Thph2 proteins triggered the transient production of reactive oxygen species (ROS) and elevated the free cytosolic calcium levels in maize leaf. Furthermore, the genes related to the jasmonate/ethylene signaling pathway were up-regulated in the wild-type maize strain. However, the ΔThph1- or ΔThph2-deletion mutants could not activate the immune defense-related genes in maize to protect against leaf disease. Therefore, we conclude that functional Thph1 and Thph2 may be required in T. harzianum to activate ISR in maize.

  4. A transposon-directed epigenetic change in ZmCCT underlies quantitative resistance to Gibberella stalk rot in maize.

    Science.gov (United States)

    Wang, Chao; Yang, Qin; Wang, Weixiang; Li, Yipu; Guo, Yanling; Zhang, Dongfeng; Ma, Xuena; Song, Wei; Zhao, Jiuran; Xu, Mingliang

    2017-09-01

    A major resistance quantitative trait locus, qRfg1, significantly enhances maize resistance to Gibberella stalk rot, a devastating disease caused by Fusarium graminearum. However, the underlying molecular mechanism remains unknown. We adopted a map-based cloning approach to identify the resistance gene at qRfg1 and examined the dynamic epigenetic changes during qRfg1-mediated maize resistance to the disease. A CCT domain-containing gene, ZmCCT, is the causal gene at the qRfg1 locus and a polymorphic CACTA-like transposable element (TE1) c. 2.4 kb upstream of ZmCCT is the genetic determinant of allelic variation. The non-TE1 ZmCCT allele is in a poised state, with predictive bivalent chromatin enriched for both repressive (H3K27me3/H3K9me3) and active (H3K4me3) histone marks. Upon pathogen challenge, this non-TE1 ZmCCT allele was promptly induced by a rapid yet transient reduction in H3K27me3/H3K9me3 and a progressive decrease in H3K4me3, leading to disease resistance. However, TE1 insertion in ZmCCT caused selective depletion of H3K4me3 and enrichment of methylated GC to suppress the pathogen-induced ZmCCT expression, resulting in disease susceptibility. Moreover, ZmCCT-mediated resistance to Gibberella stalk rot is not affected by photoperiod sensitivity. This chromatin-based regulatory mechanism enables ZmCCT to be more precise and timely in defense against F. graminearum infection. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  5. Pollen contamination in seed mixture increases the dominance of resistance to Bt maize in Spodoptera frugiperda (Lepidoptera: Noctuidae).

    Science.gov (United States)

    Yang, Fei; Kerns, David L; Brown, Sebe; Head, Graham P; Huang, Fangneng

    2017-11-01

    Seed mixture, also called 'RIB', has been used to provide refuge populations for delaying insect resistance. Pollen contamination in RIB could result in refuge kernels of non-Bt maize expressing variable Bt proteins. Data are lacking regarding the impact of pollen contamination on evolution of resistance for ear-feeding insects. Here, we used Spodoptera frugiperda and Cry1F-maize as a model to examine if pollen contamination in RIB increases the dominance of insect resistance. Pollen contamination caused >66% refuge kernels in 5:95% (non-Bt:Bt) and 20:80% RIBs to express Cry1F protein. Survival at adult stage on pure non-Bt ears was similar (54.4-63.3%) among Cry1F-susceptible (SS), Cry1F-resistant (RR) and Cry1F-heterozygous (RS) S. frugiperda. On Bt ears, survival was similar between SS and RS (0.0-1.7%), but it was significantly less than that of RR (59.2%). On the two RIB refuge ears, survival at adult stage for RS (42.3% in 5:95% RIB; 50.0% in 20:80% RIB) was significantly higher than for SS (8.7% in 5:95% RIB; 10.0% in 20:80% RIB). The results suggest that pollen contamination in RIB could increase the dominance of resistance for ear-feeding insects by significantly reducing susceptible refuge populations and supporting higher survival of heterozygotes relative to homozygous susceptible insects. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  6. Management of Field-Evolved Resistance to Bt Maize in Argentina: A Multi-Institutional Approach

    Science.gov (United States)

    Signorini, Ana M.; Abratti, Gustavo; Grimi, Damián; Machado, Marcos; Bunge, Florencia F.; Parody, Betiana; Ramos, Laura; Cortese, Pablo; Vesprini, Facundo; Whelan, Agustina; Araujo, Mónica P.; Podworny, Mariano; Cadile, Alejandro; Malacarne, María F.

    2018-01-01

    Evolution of resistance to control measures in insect populations is a natural process, and management practices are intended to delay or mitigate resistance when it occurs. During the 2012/13 season the first reports of unexpected damage by Diatraea saccharalis on some Bt maize hybrids occurred in the northeast of San Luis province, Argentina. The affected Bt technologies were Herculex I® (HX-TC1507) and VT3PRO® (MON 89034 × MON 88017*). Event TC1507 expresses Cry1F and event MON 89034 expresses Cry1A.105 and Cry2Ab2, whichr are all Bt proteins with activity against the lepidopterans D. saccharalis and Spodoptera frugiperda (MON 88017 expresses the protein Cry3Bb1 for control of coleopteran insects and the enzyme CP4EPSPS for glyphosate tolerance). The affected area is an isolated region surrounded by sierra systems to the northeast and west, with a hot semi-arid climate, long frost-free period, warm winters, hot dry summers, and woody shrubs as native flora. To manage and mitigate the development of resistance, joint actions were taken by the industry, growers and Governmental Agencies. Hybrids expressing Vip3A protein (event MIR162) and/or Cry1Ab protein (events MON 810 and Bt11) as single or stacked events are used in early plantings to control the first generations of D. saccharalis, and in later plantings date's technologies with good control of S. frugiperda. A commitment was made to plant the refuge, and pest damage is monitored. As a result, maize production in the area is sustainable and profitable with yields above the average. PMID:29888224

  7. Fine mapping of a quantitative resistance gene for gray leaf spot of maize (Zea mays L.) derived from teosinte (Z. mays ssp. parviglumis).

    Science.gov (United States)

    Zhang, Xinye; Yang, Qin; Rucker, Elizabeth; Thomason, Wade; Balint-Kurti, Peter

    2017-06-01

    In this study we mapped the QTL Qgls8 for gray leaf spot (GLS) resistance in maize to a ~130 kb region on chromosome 8 including five predicted genes. In previous work, using near isogenic line (NIL) populations in which segments of the teosinte (Zea mays ssp. parviglumis) genome had been introgressed into the background of the maize line B73, we had identified a QTL on chromosome 8, here called Qgls8, for gray leaf spot (GLS) resistance. We identified alternate teosinte alleles at this QTL, one conferring increased GLS resistance and one increased susceptibility relative to the B73 allele. Using segregating populations derived from NIL parents carrying these contrasting alleles, we were able to delimit the QTL region to a ~130 kb (based on the B73 genome) which encompassed five predicted genes.

  8. Ionic Resistance and Permselectivity Tradeoffs in Anion Exchange Membranes

    KAUST Repository

    Geise, Geoffrey M.

    2013-10-23

    Salinity gradient energy technologies, such as reverse electrodialysis (RED) and capacitive mixing based on Donnan potential (Capmix CDP), could help address the global need for noncarbon-based energy. Anion exchange membranes (AEMs) are a key component in these systems, and improved AEMs are needed in order to optimize and extend salinity gradient energy technologies. We measured ionic resistance and permselectivity properties of quaternary ammonium-functionalized AEMs based on poly(sulfone) and poly(phenylene oxide) polymer backbones and developed structure-property relationships between the transport properties and the water content and fixed charge concentration of the membranes. Ion transport and ion exclusion properties depend on the volume fraction of water in the polymer membrane, and the chemical nature of the polymer itself can influence fine-tuning of the transport properties to obtain membranes with other useful properties, such as chemical and dimensional stability. The ionic resistance of the AEMs considered in this study decreased by more than 3 orders of magnitude (i.e., from 3900 to 1.6 Ω m) and the permselectivity decreased by 6% (i.e., from 0.91 to 0.85) as the volume fraction of water in the polymer was varied by a factor of 3.8 (i.e., from 0.1 to 0.38). Water content was used to rationalize a tradeoff relationship between the permselectivity and ionic resistance of these AEMs whereby polymers with higher water content tend to have lower ionic resistance and lower permselectivity. The correlation of ion transport properties with water volume fraction and fixed charge concentration is discussed with emphasis on the importance of considering water volume fraction when interpreting ion transport data. © 2013 American Chemical Society.

  9. Defense Responses to Mycotoxin-Producing Fungi Fusarium proliferatum, F. subglutinans, and Aspergillus flavus in Kernels of Susceptible and Resistant Maize Genotypes.

    Science.gov (United States)

    Lanubile, Alessandra; Maschietto, Valentina; De Leonardis, Silvana; Battilani, Paola; Paciolla, Costantino; Marocco, Adriano

    2015-05-01

    Developing kernels of resistant and susceptible maize genotypes were inoculated with Fusarium proliferatum, F. subglutinans, and Aspergillus flavus. Selected defense systems were investigated using real-time reverse transcription-polymerase chain reaction to monitor the expression of pathogenesis-related (PR) genes (PR1, PR5, PRm3, PRm6) and genes protective from oxidative stress (peroxidase, catalase, superoxide dismutase and ascorbate peroxidase) at 72 h postinoculation. The study was also extended to the analysis of the ascorbate-glutathione cycle and catalase, superoxide dismutase, and cytosolic and wall peroxidases enzymes. Furthermore, the hydrogen peroxide and malondialdehyde contents were studied to evaluate the oxidation level. Higher gene expression and enzymatic activities were observed in uninoculated kernels of resistant line, conferring a major readiness to the pathogen attack. Moreover expression values of PR genes remained higher in the resistant line after inoculation, demonstrating a potentiated response to the pathogen invasions. In contrast, reactive oxygen species-scavenging genes were strongly induced in the susceptible line only after pathogen inoculation, although their enzymatic activity was higher in the resistant line. Our data provide an important basis for further investigation of defense gene functions in developing kernels in order to improve resistance to fungal pathogens. Maize genotypes with overexpressed resistance traits could be profitably utilized in breeding programs focused on resistance to pathogens and grain safety.

  10. Evaluation of quality protein maize hybrids for yield, association of ...

    African Journals Online (AJOL)

    The study was initiated with the objectives to evaluate quality protein maize pipeline varieties in terms of yield and yield related traits, and to investigate association of yield with its components and other desirable traits at Bako. Eighteen genotypes were planted in randomized complete block design with three replications.

  11. Quantitative trait loci for resistance to maize streak virus disease in ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-07-18

    Jul 18, 2008 ... African Journal of Biotechnology Vol. ... development ... Biotechnology Center, Kenya Agricultural Research Institute, P.O. Box 58711-00200, Nairobi, ... Maize streak virus disease is an important disease of maize in Kenya.

  12. Role of Anions Associated with the Formation and Properties of Silver Clusters.

    Science.gov (United States)

    Wang, Quan-Ming; Lin, Yu-Mei; Liu, Kuan-Guan

    2015-06-16

    including electron communication, luminescent thermochromism, single-molecule magnet, and intercluster charge transfer associated with anion-directed silver clusters have been discussed. We intend to attract chemists' attention to the role that anions could play in determining the structures and properties of metal complexes, especially clusters. We hope that this Account will stimulate more efforts in exploiting new role of anions in various metal cluster systems. Anions can do much more than counterions for charge balance, and they should be considered in the design and synthesis of cluster-based functional materials.

  13. Importance of husk covering on field infestation of maize by ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-10-20

    Oct 20, 2008 ... An experiment was conducted to determine the importance of husk covering on field infestation of maize by the maize ... high yielding plants with no consideration for resistance ..... provided financial support for the study.

  14. Species of Cercospora associated with grey leaf spot of maize

    NARCIS (Netherlands)

    Crous, P.W.; Groenewald, J.Z.; Groenewald, M.; Caldwell, P.; Braun, U.; Harrington, T.C.

    2006-01-01

    Grey leaf spot is a serious yield-reducing disease of maize (Zea mays) in many parts of the world where this crop is cultivated. The causal organism associated with the disease is Cercospora zeae-maydis. Two potential sibling species have been recognized as Groups I and II. The DNA sequences for the

  15. Species of Cercospora associated with grey leaf spot of maize.

    NARCIS (Netherlands)

    Crous, P.W.; Groenewald, J.Z.; Groenewald, M.; Caldwell, P.; Braun, U.; Harrington, T.C.

    2006-01-01

    Grey leaf spot is a serious yield-reducing disease of maize (Zea mays) in many parts of the world where this crop is cultivated. The causal organism associated with the disease is Cercospora zeae-maydis. Two potential sibling species have been recognized as Groups I and II. The DNA sequences for the

  16. Intraplant communication in maize contributes to defense against insects

    Science.gov (United States)

    The vasculature of plants act as a channel for transport of signal(s) that facilitate long-distance intraplant communication. In maize, Maize insect resistance1-Cysteine Protease (Mir1-CP), which has homology to papain-like proteases, provides defense to different feeding guilds of insect pests. Fur...

  17. Aflatoxin Accumulation in a Maize Diallel Cross

    Directory of Open Access Journals (Sweden)

    W. Paul Williams

    2015-06-01

    Full Text Available Aflatoxins, produced by the fungus Aspergillus flavus, occur naturally in maize. Contamination of maize grain with aflatoxin is a major food and feed safety problem and greatly reduces the value of the grain. Plant resistance is generally considered a highly desirable approach to reduction or elimination of aflatoxin in maize grain. In this investigation, a diallel cross was produced by crossing 10 inbred lines with varying degrees of resistance to aflatoxin accumulation in all possible combinations. Three lines that previously developed and released as sources of resistance to aflatoxin accumulation were included as parents. The 10 parental inbred lines and the 45 single crosses making up the diallel cross were evaluated for aflatoxin accumulation in field tests conducted in 2013 and 2014. Plants were inoculated with an A. flavus spore suspension seven days after silk emergence. Ears were harvested approximately 60 days later and concentration of aflatoxin in the grain determined. Parental inbred lines Mp717, Mp313E, and Mp719 exhibited low levels (3–12 ng/g of aflatoxin accumulation. In the diallel analysis, both general and specific combining ability were significant sources of variation in the inheritance of resistance to aflatoxin accumulation. General combining ability effects for reduced aflatoxin accumulation were greatest for Mp494, Mp719, and Mp717. These lines should be especially useful in breeding for resistance to aflatoxin accumulation. Breeding strategies, such as reciprocal recurrent selection, would be appropriate.

  18. Strong oviposition preference for Bt over non-Bt maize in Spodoptera frugiperda and its implications for the evolution of resistance

    Science.gov (United States)

    2014-01-01

    Background Transgenic crops expressing Bt toxins have substantial benefits for growers in terms of reduced synthetic insecticide inputs, area-wide pest management and yield. This valuable technology depends upon delaying the evolution of resistance. The ‘high dose/refuge strategy’, in which a refuge of non-Bt plants is planted in close proximity to the Bt crop, is the foundation of most existing resistance management. Most theoretical analyses of the high dose/refuge strategy assume random oviposition across refugia and Bt crops. Results In this study we examined oviposition and survival of Spodoptera frugiperda across conventional and Bt maize and explored the impact of oviposition behavior on the evolution of resistance in simulation models. Over six growing seasons oviposition rates per plant were higher in Bt crops than in refugia. The Cry1F Bt maize variety retained largely undamaged leaves, and oviposition preference was correlated with the level of feeding damage in the refuge. In simulation models, damage-avoiding oviposition accelerated the evolution of resistance and either led to requirements for larger refugia or undermined resistance management altogether. Since larval densities affected oviposition preferences, pest population dynamics affected resistance evolution: larger refugia were weakly beneficial for resistance management if they increased pest population sizes and the concomitant degree of leaf damage. Conclusions Damaged host plants have reduced attractiveness to many insect pests, and crops expressing Bt toxins are generally less damaged than conventional counterparts. Resistance management strategies should take account of this behavior, as it has the potential to undermine the effectiveness of existing practice, especially in the tropics where many pests are polyvoltinous. Efforts to bring down total pest population sizes and/or increase the attractiveness of damaged conventional plants will have substantial benefits for slowing the

  19. Determination of molecular markers associated with anthesis-silking interval in maize

    International Nuclear Information System (INIS)

    Simpson, J.

    1998-01-01

    Maize lines contrasting in anthesis-silking, interval (ASI), a trait strongly linked to drought tolerance, have been analyzed under different water stress conditions in the field and with molecular markers. Correlation of marker and field data has revealed molecular markers strongly associated with flowering and yield traits. (author)

  20. Predator Preference for Bt-Fed Spodoptera frugiperda (Lepidoptera: Noctuidae) Prey: Implications for Insect Resistance Management in Bt Maize Seed Blends.

    Science.gov (United States)

    Svobodová, Z; Burkness, E C; Skoková Habuštová, O; Hutchison, W D

    2017-06-01

    Understanding indirect, trophic-level effects of genetically engineered plants, expressing insecticidal proteins derived from the bacterium, Bacillus thuringiensis (Bt), is essential to the ecological risk assessment process. In this study, we examine potential indirect, trophic-level effects of Bt-sensitive prey using the predator, Harmonia axyridis (Pallas), feeding upon Spodoptera frugiperda (J.E. Smith) larvae, which had delayed development (lower body mass) following ingestion of Cry1Ab maize leaves. We found no adverse effects on development and survival when H. axyridis larvae were fed S. frugiperda larvae that had fed on Cry1Ab maize tissue. Presence of Cry1Ab in H. axyridis decreased considerably after switching to another diet within 48 h. In a no-choice assay, H. axyridis larvae consumed more Bt-fed S. frugiperda than non-Bt-fed larvae. Preference for S. frugiperda feeding on Bt maize was confirmed in subsequent choice assays with H. axyridis predation on Bt-fed, 1-5-d-old S. frugiperda larvae. We suggest that H. axyridis preferred prey, not based on whether it had fed on Bt or non-Bt maize, but rather on larval mass, and they compensated for the nutritional deficiency of lighter larvae through increased consumption. Pest larvae with variable levels of resistance developing on Bt diet are often stunted versus sensitive larvae developing on non-Bt diet. It is possible that such larvae may be preferentially removed from local field populations. These results may have implications for insect resistance management and may be played out under field conditions where seed blends of Bt and non-Bt hybrids are planted. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  1. Interaction of 2,4-D or Dicamba with Glufosinate for Control of Glyphosate-Resistant Giant Ragweed (Ambrosia trifida L. in Glufosinate-Resistant Maize (Zea mays L.

    Directory of Open Access Journals (Sweden)

    Zahoor A. Ganie

    2017-07-01

    Full Text Available Glyphosate-resistant (GR giant ragweed is a problematic broadleaf weed in crops including maize and soybean in the Midwestern United States. Commercialization of crops with 2,4-D or dicamba and glufosinate resistance will allow post-emergence (POST applications of these herbicides. Therefore, information is needed on how 2,4-D/dicamba will interact with glufosinate in various rate combinations. The objectives of this study were to evaluate the interaction of glufosinate plus 2,4-D and/or dicamba for control of GR giant ragweed, and to determine their effect on GR giant ragweed density, biomass, maize injury, and yield. Field experiments were conducted in 2013 and 2014 in a field infested with GR giant ragweed in Nebraska, United States. The treatments included POST applications of glufosinate (450 or 590 g ai ha-1, 2,4-D, or dicamba at 280 or 560 g ae ha-1 applied alone and in tank-mixtures in glufosinate-resistant maize. The results showed that dicamba applied alone resulted in 56 to 62% and 73 to 83% control at 14 and 28 days after treatment (DAT, respectively, and ≥95% control at 60 DAT or at harvest compared to 17 to 30% and 57 to 73% control with 2,4-D applied alone at 280 and 560 g ai ha-1, respectively. Glufosinate tank-mixed with 2,4-D and/or dicamba consistently provided ≥89% control of GR giant ragweed, except that control with glufosinate plus 2,4-D varied from 80 to 92% at 60 DAT and at harvest. The comparison between the observed and expected control (determined by Colby’s equation suggested an additive interaction between glufosinate and 2,4-D or dicamba for control of GR giant ragweed. Contrast analysis also indicated that GR giant ragweed control with glufosinate plus 2,4-D or dicamba was either consistently higher or comparable with individual herbicides excluding 2,4-D applied alone. Herbicide programs, excluding 2,4-D at 280 g ae ha-1, resulted in ≥80% reduction in GR giant ragweed density. Tank-mixing glufosinate with

  2. Interaction of maize chromatin-associated HMG proteins with mononucleosomes

    DEFF Research Database (Denmark)

    Lichota, J.; Grasser, Klaus D.

    2003-01-01

    maize HMGA and five different HMGB proteins with mononucleosomes (containing approx. 165 bp of DNA) purified from micrococcal nuclease-digested maize chromatin. The HMGB proteins interacted with the nucleosomes independent of the presence of the linker histone H1, while the binding of HMGA...

  3. Combining powers of linkage and association mapping for precise dissection of QTL controlling resistance to gray leaf spot disease in maize (Zea mays L.).

    Science.gov (United States)

    Mammadov, Jafar; Sun, Xiaochun; Gao, Yanxin; Ochsenfeld, Cherie; Bakker, Erica; Ren, Ruihua; Flora, Jonathan; Wang, Xiujuan; Kumpatla, Siva; Meyer, David; Thompson, Steve

    2015-11-10

    Gray Leaf Spot (GLS causal agents Cercospora zeae-maydis and Cercospora zeina) is one of the most important foliar diseases of maize in all areas where the crop is being cultivated. Although in the USA the situation with GLS severity is not as critical as in sub-Saharan Africa or Brazil, the evidence of climate change, increasing corn monoculture as well as the narrow genetic base of North American resistant germplasm can turn the disease into a serious threat to US corn production. The development of GLS resistant cultivars is one way to control the disease. In this study we combined the high QTL detection power of genetic linkage mapping with the high resolution power of genome-wide association study (GWAS) to precisely dissect QTL controlling GLS resistance and identify closely linked molecular markers for robust marker-assisted selection and trait introgression. Using genetic linkage analysis with a small bi-parental mapping population, we identified four GLS resistance QTL on chromosomes 1, 6, 7, and 8, which were validated by GWAS. GWAS enabled us to dramatically increase the resolution within the confidence intervals of the above-mentioned QTL. Particularly, GWAS revealed that QTLGLSchr8, detected by genetic linkage mapping as a locus with major effect, was likely represented by two QTL with smaller effects. Conducted in parallel, GWAS of days-to-silking demonstrated the co-localization of flowering time QTL with GLS resistance QTL on chromosome 7 indicating that either QTLGLSchr7 is a flowering time QTL or it is a GLS resistance QTL that co-segregates with the latter. As a result, this genetic linkage - GWAS hybrid mapping system enabled us to identify one novel GLS resistance QTL (QTLGLSchr8a) and confirm with more refined positions four more previously mapped QTL (QTLGLSchr1, QTLGLSchr6, QTLGLSchr7, and QTLGLSchr8b). Through the novel Single Donor vs. Elite Panel method we were able to identify within QTL confidence intervals SNP markers that would be

  4. Effect of progressive drought stress on growth, leaf gas exchange, and antioxidant production in two maize cultivars.

    Science.gov (United States)

    Anjum, Shakeel Ahmad; Tanveer, Mohsin; Ashraf, Umair; Hussain, Saddam; Shahzad, Babar; Khan, Imran; Wang, Longchang

    2016-09-01

    Drought stress is one of the major environmental factors responsible for reduction in crop productivity. In the present study, responses of two maize cultivars (Rung Nong 35 and Dong Dan 80) were examined to explicate the growth, yield, leaf gas exchange, leaf water contents, osmolyte accumulation, membrane lipid peroxidation, and antioxidant activity under progressive drought stress. Maize cultivars were subjected to varying field capacities (FC) viz., well-watered (80 % FC) and drought-stressed (35 % FC) at 45 days after sowing. The effects of drought stress were analyzed at 5, 10, 15, 20, ad 25 days after drought stress (DAS) imposition. Under prolonged drought stress, Rung Nong 35 exhibited higher reduction in growth and yield as compared to Dong Dan 80. Maize cultivar Dong Dan 80 showed higher leaf relative water content (RWC), free proline, and total carbohydrate accumulation than Run Nong 35. Malondialdehyde (MDA) and superoxide anion were increased with prolongation of drought stress, with higher rates in cultivar Run Nong 35 than cultivar Dong Dan 80. Higher production of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) and glutathione reductase (GR) resulted in improved growth and yield in Dong Dan 80. Overall, the cultivar Dong Dan 80 was better able to resist the detrimental effects of progressive drought stress as indicated by better growth and yield due to higher antioxidant enzymes, reduced lipid peroxidation, better accumulation of osmolytes, and maintenance of tissue water contents.

  5. Reducing nitrogen crossover in microbial reverse-electrodialysis cells by using adjacent anion exchange membranes and anion exchange resin

    KAUST Repository

    Wallack, Maxwell J.; Geise, Geoffrey M.; Hatzell, Marta C.; Hickner, Michael A.; Logan, Bruce E.

    2015-01-01

    Microbial reverse electrodialysis cells (MRECs) combine power generation from salinity gradient energy using reverse electrodialysis (RED), with power generation from organic matter using a microbial fuel cell. Waste heat can be used to distill ammonium bicarbonate into high (HC) and low salt concentration (LC) solutions for use in the RED stack, but nitrogen crossover into the anode chamber must be minimized to avoid ammonia loses, and foster a healthy microbial community. To reduce nitrogen crossover, an additional low concentration (LC) chamber was inserted before the anode using an additional anion exchange membrane (AEM) next to another AEM, and filled with different amounts of anion or cation ion exchange resins. Addition of the extra AEM increased the ohmic resistance of the test RED stack from 103 Ω cm2 (1 AEM) to 295 Ω cm2 (2 AEMs). However, the use of the anion exchange resin decreased the solution resistance of the LC chamber by 74% (637 Ω cm2, no resin; 166 Ω cm2 with resin). Nitrogen crossover into the anode chamber was reduced by up to 97% using 50% of the chamber filled with an anion exchange resin compared to the control (no additional chamber). The added resistance contributed by the use of the additional LC chamber could be compensated for by using additional LC and HC membrane pairs in the RED stack.

  6. Regional pest suppression associated with widespread Bt maize adoption benefits vegetable growers.

    Science.gov (United States)

    Dively, Galen P; Venugopal, P Dilip; Bean, Dick; Whalen, Joanne; Holmstrom, Kristian; Kuhar, Thomas P; Doughty, Hélène B; Patton, Terry; Cissel, William; Hutchison, William D

    2018-03-27

    Transgenic crops containing the bacterium Bacillus thuringiensis (Bt) genes reduce pests and insecticide usage, promote biocontrol services, and economically benefit growers. Area-wide Bt adoption suppresses pests regionally, with declines expanding beyond the planted Bt crops into other non-Bt crop fields. However, the offsite benefits to growers of other crops from such regional suppression remain uncertain. With data spanning 1976-2016, we demonstrate that vegetable growers benefit via decreased crop damage and insecticide applications in relation to pest suppression in the Mid-Atlantic United States. We provide evidence for the regional suppression of Ostrinia nubilalis (Hübner), European corn borer, and Helicoverpa zea (Boddie), corn earworm, populations in association with widespread Bt maize adoption (1996-2016) and decreased economic levels for injury in vegetable crops [peppers ( Capsicum annuum L.), green beans ( Phaseolus vulgaris L.), and sweet corn ( Zea mays L., convar. saccharata )] compared with the pre-Bt period (1976-1995). Moth populations of both species significantly declined in association with widespread Bt maize (field corn) adoption, even as increased temperatures buffered the population reduction. We show marked decreases in the number of recommended insecticidal applications, insecticides applied, and O. nubilalis damage in vegetable crops in association with widespread Bt maize adoption. These offsite benefits to vegetable growers in the agricultural landscape have not been previously documented, and the positive impacts identified here expand on the reported ecological effects of Bt adoption. Our results also underscore the need to account for offsite economic benefits of pest suppression, in addition to the direct economic benefits of Bt crops.

  7. Potential subchronic food safety of the stacked trait transgenic maize GH5112E-117C in Sprague-Dawley rats.

    Science.gov (United States)

    Han, Shiwen; Zou, Shiying; He, Xiaoyun; Huang, Kunlun; Mei, Xiaohong

    2016-08-01

    The food safety of stacked trait genetically modified (GM) maize GH5112E-117C containing insect-resistance gene Cry1Ah and glyphosate-resistant gene G2-aroA was evaluated in comparison to non-GM Hi-II maize fed to Sprague-Dawley rats during a 90-day subchronic feeding study. Three different dietary concentrations (12.5, 25 and 50 %, w/w) of the GM maize were used or its corresponding non-GM maize. No biologically significant differences in the animals' clinical signs, body weights, food consumption, hematology, clinical chemistry, organ weights and histopathology were found between the stacked trait GM maize groups, and the non-GM maize groups. The results of the 90-day subchronic feeding study demonstrated that the stacked trait GM maize GH5112E-117C is as safe as the conventional non-GM maize Hi-II.

  8. Putting the Function in Maize Genomics

    Directory of Open Access Journals (Sweden)

    Stephen P. Moose

    2009-07-01

    Full Text Available The 51st Maize Genetics Conference was held March 12–15, 2009 at Pheasant Run Resort in St. Charles, Illinois. Nearly 500 attendees participated in a scientific program (available at covering a wide range of topics which integrate the rich biology of maize with recent discoveries in our understanding of the highly dynamic maize genome. Among the many research themes highlighted at the conference, the historical emphasis on studying the tremendous phenotypic diversity of maize now serves as the foundation for maize as a leading experimental system to characterize the mechanisms that generate variation in complex plant genomes and associate evolutionary change with phenotypes of interest.

  9. Risk Assessment of Genetically Engineered Maize Resistant to Diabrotica spp.: Influence on Above-Ground Arthropods in the Czech Republic.

    Directory of Open Access Journals (Sweden)

    Zdeňka Svobodová

    Full Text Available Transgenic maize MON88017, expressing the Cry3Bb1 toxin from Bacillus thuringiensis (Bt maize, confers resistance to corn rootworms (Diabrotica spp. and provides tolerance to the herbicide glyphosate. However, prior to commercialization, substantial assessment of potential effects on non-target organisms within agroecosystems is required. The MON88017 event was therefore evaluated under field conditions in Southern Bohemia in 2009-2011, to detect possible impacts on the above-ground arthropod species. The study compared MON88017, its near-isogenic non-Bt hybrid DK315 (treated or not treated with the soil insecticide Dursban 10G and two non-Bt reference hybrids (KIPOUS and PR38N86. Each hybrid was grown on five 0.5 ha plots distributed in a 14-ha field with a Latin square design. Semiquantitative ELISA was used to verify Cry3Bb1 toxin levels in the Bt maize. The species spectrum of non-target invertebrates changed during seasons and was affected by weather conditions. The thrips Frankliniella occidentalis was the most abundant species in all three successive years. The next most common species were aphids Rhopalosiphum padi and Metopolophium dirhodum. Frequently observed predators included Orius spp. and several species within the Coccinellidae. Throughout the three-year study, analysis of variance indicated some significant differences (P<0.05. Multivariate analysis showed that the abundance and diversity of plant dwelling insects was similar in maize with the same genetic background, for both Bt (MON88017 and non-Bt (DK315 untreated or insecticide treated. KIPOUS and PR38N86 showed some differences in species abundance relative to the Bt maize and its near-isogenic hybrid. However, the effect of management regime on arthropod community was insignificant and accounted only for a negligible portion of the variability.

  10. Effect of the foliar enrichment and herbicides on maize and associated weeds irrigated with drainage water

    Directory of Open Access Journals (Sweden)

    Roshdy M.H. Tagour

    2017-12-01

    Full Text Available A two-year field experiment was conducted during summer seasons of 2013 and 2014, which were irrigated by drainage water which belong to salinity class (C3S1 to C4S2, to study the effect of the foliar enrichment namely (Anti-stress and weed management treatments (some pre and post-emergence herbicides and two-hand hoeing on maize growth, yield, yield components and chemical composition of maize grains and associated weeds (Portulaca oleracea, Amaranthus retroflexus and Echinochloa colonum. The results illustrated that application of the foliar enrichment enhanced the dry weight of weeds and increased maize growth characters, yield and yield components and total crude protein and total oil percentage of grain maize, as compared with untreated treatment. All weed management treatments caused a significant reduction in total dry weight of weeds at 60 and 80 days after sowing in both seasons. Two-hand hoeing treatment exerted the highest decrease in total dry weight of weeds followed by metribuzin, oxadiagyl, fluroxypyr and bentazon, respectively at 60 and 80 days after sowing compared with other weed management treatments. While, the highest values of maize growth, yield, yield components and maize grains' content of protein and oil was obtained with two-hand hoeing followed by metribuzin, oxadiagyl, fluroxypyr and bentazon, respectively. While, two hands hoeing produced the maximum values of leaf area, ear length, the weight of kernels plant−1, but applying of metribuzin treatment gave the highest values of total oil percentage of grain maize when the foliar enrichment was used.

  11. Anion exchanger and the resistance against thermal haemolysis.

    Science.gov (United States)

    Ivanov, I T; Zheleva, A; Zlatanov, I

    2011-01-01

    4,4'-Diiso-thiocyanato stilbene-2,2'-disulphonic acid (DIDS) is a membrane-impermeable, highly specific covalent inhibitor and powerful thermal stabiliser of the anion exchanger (AE1), the major integral protein of erythrocyte membrane (EM). Suspensions of control and DIDS-treated (15 µM, pH 8.2) human erythrocytes were heated from 20° to 70°C using various but constant heating rates (1-8°C/min). The cellular electrolyte leakage exhibited a sigmoidal response to temperature as detected by conductometry. The critical midpoint temperature of leakage, T(mo), extrapolated to low heating rate (0.5°C/min) was used as a measure for EM thermostability. T(mo) was greater for DIDS-treated erythrocytes, 63.2° ± 0.3°C, than for intact erythrocytes, 60.7° ± 0.2°C. The time, t(1/2), for 50% haemolysis of erythrocytes, exposed to 53°C was used as a measure for the resistance of erythrocytes against thermal haemolysis. The t(1/2) was also greater for DIDS-treated erythrocytes, 63 ± 3 min, than for intact erythrocytes, 38 ± 2 min. The fluorescent label N-(3-pyrenyl)maleimide and EPR spin label 3-maleimido-proxyl, covalently bound to sulphydryl groups of major EM proteins, were used to monitor the changes in molecular motions during transient heating. Both labels reported an intensification of the motional dynamics at the denaturation temperatures of spectrin (50°C) and AE1 (67°C), and, surprisingly, immobilisation of a major EM protein, presumably the AE1, at T(mo). The above results are interpreted in favour of the possible involvement of a predenaturational rearrangement of AE1 copies in the EM thermostability and the resistance against thermal haemolysis.

  12. Implications Of Soil Resistivity Measurements Using The Electrical Resistivity Method A Case Study Of A Maize Farm Under Different Soil Preparation Modes At KNUST Agricultural Research Station Kumasi

    Directory of Open Access Journals (Sweden)

    Jakalia

    2015-01-01

    Full Text Available Abstract Continuous vertical electrical sounding CVES technique was used to investigate the soil moisture content of a maize farm at the Kwame Nkrumah University of Science and Technology KNUST Agricultural Research Station ARS Kumasi Ghana. The soils of the maize farm were categorized into four different land preparation modes ploughed-harrowed ploughed hoed and no-till plot. Time-lapse measurements with CVES was carried out using the multi-electrode Wenner array to investigate soil moisture variation with the help of the ABEM Terrameter SAS 4000 resistivity meter. The results showed a heterogeneous distribution of soil moisture content both spatially and temporally. Most of the water available for plants uptake was within a depth of 0.20 0.40 m which coincided with the root zones of the maize crops. In addition the no-till plot was found to conserve more moisture during dry weather conditions than the rest of the plots. The research shows that CVES technique is applicable in monitoring shallow soil water content in the field and the results obtained could be used to optimize irrigation scheduling and to assess the potential for variable-rate irrigation.

  13. Superoxide anion radicals induce IGF-1 resistance through concomitant activation of PTP1B and PTEN

    Science.gov (United States)

    Singh, Karmveer; Maity, Pallab; Krug, Linda; Meyer, Patrick; Treiber, Nicolai; Lucas, Tanja; Basu, Abhijit; Kochanek, Stefan; Wlaschek, Meinhard; Geiger, Hartmut; Scharffetter-Kochanek, Karin

    2015-01-01

    The evolutionarily conserved IGF-1 signalling pathway is associated with longevity, metabolism, tissue homeostasis, and cancer progression. Its regulation relies on the delicate balance between activating kinases and suppressing phosphatases and is still not very well understood. We report here that IGF-1 signalling in vitro and in a murine ageing model in vivo is suppressed in response to accumulation of superoxide anions () in mitochondria, either by chemical inhibition of complex I or by genetic silencing of -dismutating mitochondrial Sod2. The -dependent suppression of IGF-1 signalling resulted in decreased proliferation of murine dermal fibroblasts, affected translation initiation factors and suppressed the expression of α1(I), α1(III), and α2(I) collagen, the hallmarks of skin ageing. Enhanced led to activation of the phosphatases PTP1B and PTEN, which via dephosphorylation of the IGF-1 receptor and phosphatidylinositol 3,4,5-triphosphate dampened IGF-1 signalling. Genetic and pharmacologic inhibition of PTP1B and PTEN abrogated -induced IGF-1 resistance and rescued the ageing skin phenotype. We thus identify previously unreported signature events with , PTP1B, and PTEN as promising targets for drug development to prevent IGF-1 resistance-related pathologies. PMID:25520316

  14. Correlation between Quantumchemically Calculated LUMO Energies and the Electrochemical Window of Ionic Liquids with Reduction-Resistant Anions

    Directory of Open Access Journals (Sweden)

    Wim Buijs

    2012-01-01

    Full Text Available Quantum chemical calculations showed to be an excellent method to predict the electrochemical window of ionic liquids with reduction-resistant anions. A good correlation between the LUMO energy and the electrochemical window is observed. Surprisingly simple but very fast semiempirical calculations are in full record with density functional theory calculations and are a very attractive tool in the design and optimization of ionic liquids for specific purposes.

  15. Identification of multiple ear-colonizing insect and disease resistance in CIMMYT maize inbred lines with varying levels of silk maysin.

    Science.gov (United States)

    Ni, Xinzhi; Krakowsky, Matthew D; Buntin, G David; Rector, Brian G; Guo, Baozhu; Snook, Maurice E

    2008-08-01

    Ninety four corn inbred lines selected from International Center for the Improvement of Maize and Wheat (CIMMYT) in Mexico were evaluated for levels of silk maysin in 2001 and 2002. Damage by major ear-feeding insects [i.e., corn earworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae); maize weevil, Sitophilus zeamais (Motschulsky) (Coleoptera: Curculionidae); brown stink bug, Euschistus servus (Say); southern green stink bugs, Nezara viridula (L.) (Heteroptera: Pentatomidae)], and common smut [Ustilago maydis DC (Corda)] infection on these inbred lines were evaluated in 2005 and 2006 under subtropical conditions at Tifton, GA. Ten inbred lines possessing good agronomic traits were also resistant to the corn earworm. The correlation between ear-feeding insect damage or smut infection and three phenotypic traits (silk maysin level, husk extension, and husk tightness of corn ears) was also examined. Corn earworm and stink bug damage was negatively correlated to husk extension, but not to either silk maysin levels or husk tightness. In combination with the best agronomic trait ratings that show the least corn earworm and stink bug damage, lowest smut infection rate, and good insect-resistant phenotypic traits (i.e., high maysin and good husk coverage and husk tightness), 10 best inbred lines (CML90, CML92, CML94, CML99, CML104, CML108, CML114, CML128, CML137, and CML373) were identified from the 94 lines examined. These selected inbred lines will be used for further examination of their resistance mechanisms and development of new corn germplasm that confers multiple ear-colonizing pest resistance.

  16. Integrating soil conservation practices and glyphosate-resistant crops: impacts on soil.

    Science.gov (United States)

    Locke, Martin A; Zablotowicz, Robert M; Reddy, Krishna N

    2008-04-01

    Conservation practices often associated with glyphosate-resistant crops, e.g. limited tillage and crop cover, improve soil conditions, but only limited research has evaluated their effects on soil in combination with glyphosate-resistant crops. It is assumed that conservation practices have similar benefits to soil whether or not glyphosate-resistant crops are used. This paper reviews the impact on soil of conservation practices and glyphosate-resistant crops, and presents data from a Mississippi field trial comparing glyphosate-resistant and non-glyphosate-resistant maize (Zea mays L.) and cotton (Gossypium hirsutum L.) under limited tillage management. Results from the reduced-tillage study indicate differences in soil biological and chemical properties owing to glyphosate-resistant crops. Under continuous glyphosate-resistant maize, soils maintained greater soil organic carbon and nitrogen as compared with continuous non-glyphosate-resistant maize, but no differences were measured in continuous cotton or in cotton rotated with maize. Soil microbial community structure based on total fatty acid methyl ester analysis indicated a significant effect of glyphosate-resistant crop following 5 years of continuous glyphosate-resistant crop as compared with the non-glyphosate-resistant crop system. Results from this study, as well as the literature review, indicate differences attributable to the interaction of conservation practices and glyphosate-resistant crop, but many are transient and benign for the soil ecosystem. Glyphosate use may result in minor effects on soil biological/chemical properties. However, enhanced organic carbon and plant residues in surface soils under conservation practices may buffer potential effects of glyphosate. Long-term field research established under various cropping systems and ecological regions is needed for critical assessment of glyphosate-resistant crop and conservation practice interactions. Copyright (c) 2008 by John Wiley & Sons

  17. Physiological quality and gene expression related to heat-resistant proteins at different stages of development of maize seeds.

    Science.gov (United States)

    Andrade, T; Von Pinho, E V R; Von Pinho, R G; Oliveira, G E; Andrade, V; Fernandes, J S

    2013-09-13

    We quantified and characterized the expression of heat-resistant proteins during seed development of maize lines with distinct levels of tolerance to high drying temperature. A corn field was planted for multiplication of seeds of different lines, two tolerant and two non-tolerant to high drying temperatures. Harvest of the seeds was carried out at various stages of development and they were then subjected to tests of moisture content, germination, first count of germination, accelerated aging, and cold test. The seeds were stored in a freezer for later analysis of expression of heat-resistant proteins by means of real-time PCR, electrophoresis, and spectrophotometry. We observed that heat-resistant proteins are expressed in a differential manner in seeds from different lines and at different stages of development. The expression of heat-resistant proteins was earlier in lines tolerant to high drying temperatures. Greater germination and vigor values was found for seeds collected at the last stage of development.

  18. Functional mechanisms of drought tolerance in subtropical maize (Zea mays L.) identified using genome-wide association mapping.

    Science.gov (United States)

    Thirunavukkarasu, Nepolean; Hossain, Firoz; Arora, Kanika; Sharma, Rinku; Shiriga, Kaliyugam; Mittal, Swati; Mohan, Sweta; Namratha, Pottekatt Mohanlal; Dogga, Sreelatha; Rani, Tikka Shobha; Katragadda, Sumalini; Rathore, Abhishek; Shah, Trushar; Mohapatra, Trilochan; Gupta, Hari Shankar

    2014-12-24

    Earlier studies were focused on the genetics of temperate and tropical maize under drought. We identified genetic loci and their association with functional mechanisms in 240 accessions of subtropical maize using a high-density marker set under water stress. Out of 61 significant SNPs (11 were false-discovery-rate-corrected associations), identified across agronomic traits, models, and locations by subjecting the accessions to water stress at flowering stage, 48% were associated with drought-tolerant genes. Maize gene models revealed that SNPs mapped for agronomic traits were in fact associated with number of functional traits as follows: stomatal closure, 28; flowering, 15; root development, 5; detoxification, 4; and reduced water potential, 2. Interactions of these SNPS through the functional traits could lead to drought tolerance. The SNPs associated with ABA-dependent signalling pathways played a major role in the plant's response to stress by regulating a series of functions including flowering, root development, auxin metabolism, guard cell functions, and scavenging reactive oxygen species (ROS). ABA signalling genes regulate flowering through epigenetic changes in stress-responsive genes. ROS generated by ABA signalling are reduced by the interplay between ethylene, ABA, and detoxification signalling transductions. Integration of ABA-signalling genes with auxin-inducible genes regulates root development which in turn, maintains the water balance by regulating electrochemical gradient in plant. Several genes are directly or indirectly involved in the functioning of agronomic traits related to water stress. Genes involved in these crucial biological functions interacted significantly in order to maintain the primary as well as exclusive functions related to coping with water stress. SNPs associated with drought-tolerant genes involved in strategic biological functions will be useful to understand the mechanisms of drought tolerance in subtropical maize.

  19. Maize Bioactive Peptides against Cancer

    Science.gov (United States)

    Díaz-Gómez, Jorge L.; Castorena-Torres, Fabiola; Preciado-Ortiz, Ricardo E.; García-Lara, Silverio

    2017-06-01

    Cancer is one of the main chronic degenerative diseases worldwide. In recent years, consumption of whole-grain cereals and their derived food products has been associated with reduction risks of various types of cancer. Cereals main biomolecules includes proteins, peptides, and amino acids present in different quantities within the grain. The nutraceutical properties associated with peptides exerts biological functions that promote health and prevent this disease. In this review, we report the current status and advances on maize peptides regarding bioactive properties that have been reported such as antioxidant, antihypertensive, hepatoprotective, and anti-tumour activities. We also highlighted its biological potential through which maize bioactive peptides exert anti-cancer activity. Finally, we analyse and emphasize the possible areas of application for maize peptides.

  20. Fine mapping of a quantitative resistance gene for gray leaf spot of maize (Zea mays L.) derived from teosinte (Z. mays ssp. parviglumis)

    Science.gov (United States)

    In previous work, using near isogenic line (NIL) populations in which segments of the tesosinte (Zea mays ssp. parviglumis) genome had been introgressed into the background of the maize line B73, we had identified a QTL on chromosome 8, here called Qgls8, for gray leaf spot resistance. We identified...

  1. Water permeation through anion exchange membranes

    Science.gov (United States)

    Luo, Xiaoyan; Wright, Andrew; Weissbach, Thomas; Holdcroft, Steven

    2018-01-01

    An understanding of water permeation through solid polymer electrolyte (SPE) membranes is crucial to offset the unbalanced water activity within SPE fuel cells. We examine water permeation through an emerging class of anion exchange membranes, hexamethyl-p-terphenyl poly (dimethylbenzimidazolium) (HMT-PMBI), and compare it against series of membrane thickness for a commercial anion exchange membrane (AEM), Fumapem® FAA-3, and a series of proton exchange membranes, Nafion®. The HMT-PMBI membrane is found to possess higher water permeabilities than Fumapem® FAA-3 and comparable permeability than Nafion (H+). By measuring water permeation through membranes of different thicknesses, we are able to decouple, for the first time, internal and interfacial water permeation resistances through anion exchange membranes. Permeation resistances on liquid/membrane interface is found to be negligible compared to that for vapor/membrane for both series of AEMs. Correspondingly, the resistance of liquid water permeation is found to be one order of magnitude smaller compared to that of vapor water permeation. HMT-PMBI possesses larger effective internal water permeation coefficient than both Fumapem® FAA-3 and Nafion® membranes (60 and 18% larger, respectively). In contrast, the effective interfacial permeation coefficient of HMT-PMBI is found to be similar to Fumapem® (±5%) but smaller than Nafion®(H+) (by 14%).

  2. Genomic-based-breeding tools for tropical maize improvement.

    Science.gov (United States)

    Chakradhar, Thammineni; Hindu, Vemuri; Reddy, Palakolanu Sudhakar

    2017-12-01

    Maize has traditionally been the main staple diet in the Southern Asia and Sub-Saharan Africa and widely grown by millions of resource poor small scale farmers. Approximately, 35.4 million hectares are sown to tropical maize, constituting around 59% of the developing worlds. Tropical maize encounters tremendous challenges besides poor agro-climatic situations with average yields recorded <3 tones/hectare that is far less than the average of developed countries. On the contrary to poor yields, the demand for maize as food, feed, and fuel is continuously increasing in these regions. Heterosis breeding introduced in early 90 s improved maize yields significantly, but genetic gains is still a mirage, particularly for crop growing under marginal environments. Application of molecular markers has accelerated the pace of maize breeding to some extent. The availability of array of sequencing and genotyping technologies offers unrivalled service to improve precision in maize-breeding programs through modern approaches such as genomic selection, genome-wide association studies, bulk segregant analysis-based sequencing approaches, etc. Superior alleles underlying complex traits can easily be identified and introgressed efficiently using these sequence-based approaches. Integration of genomic tools and techniques with advanced genetic resources such as nested association mapping and backcross nested association mapping could certainly address the genetic issues in maize improvement programs in developing countries. Huge diversity in tropical maize and its inherent capacity for doubled haploid technology offers advantage to apply the next generation genomic tools for accelerating production in marginal environments of tropical and subtropical world. Precision in phenotyping is the key for success of any molecular-breeding approach. This article reviews genomic technologies and their application to improve agronomic traits in tropical maize breeding has been reviewed in

  3. Development of nematode resistance maize varieties by diallel ...

    African Journals Online (AJOL)

    The study was conducted in 2014 and 2015 cropping season at the Centre for agricultural research and extension (CARE) of Federal University of Technology, Owerri (FUTO) located at latitude 050 27‖ N and longitude 070 O2‖ E within the rain forest agro-ecology of Nigeria; to assess the tolerance level of maize ...

  4. A predicted protein interactome identifies conserved global networks and disease resistance subnetworks in maize.

    Directory of Open Access Journals (Sweden)

    Matt eGeisler

    2015-06-01

    Full Text Available Interactomes are genome-wide roadmaps of protein-protein interactions. They have been produced for humans, yeast, the fruit fly, and Arabidopsis thaliana and have become invaluable tools for generating and testing hypotheses. A predicted interactome for Zea mays (PiZeaM is presented here as an aid to the research community for this valuable crop species. PiZeaM was built using a proven method of interologs (interacting orthologs that were identified using both one-to-one and many-to-many orthology between genomes of maize and reference species. Where both maize orthologs occurred for an experimentally determined interaction in the reference species, we predicted a likely interaction in maize. A total of 49,026 unique interactions for 6,004 maize proteins were predicted. These interactions are enriched for processes that are evolutionarily conserved, but include many otherwise poorly annotated proteins in maize. The predicted maize interactions were further analyzed by comparing annotation of interacting proteins, including different layers of ontology. A map of pairwise gene co-expression was also generated and compared to predicted interactions. Two global subnetworks were constructed for highly conserved interactions. These subnetworks showed clear clustering of proteins by function. Another subnetwork was created for disease response using a bait and prey strategy to capture interacting partners for proteins that respond to other organisms. Closer examination of this subnetwork revealed the connectivity between biotic and abiotic hormone stress pathways. We believe PiZeaM will provide a useful tool for the prediction of protein function and analysis of pathways for Z. mays researchers and is presented in this paper as a reference tool for the exploration of protein interactions in maize.

  5. Role of chloride ions in the promotion of auxin-induced growth of maize coleoptile segments.

    Science.gov (United States)

    Burdach, Zbigniew; Kurtyka, Renata; Siemieniuk, Agnieszka; Karcz, Waldemar

    2014-10-01

    The mechanism of auxin action on ion transport in growing cells has not been determined in detail. In particular, little is known about the role of chloride in the auxin-induced growth of coleoptile cells. Moreover, the data that do exist in the literature are controversial. This study describes experiments that were carried out with maize (Zea mays) coleoptile segments, this being a classical model system for studies of plant cell elongation growth. Growth kinetics or growth and pH changes were recorded in maize coleoptiles using two independent measuring systems. The growth rate of the segments was measured simultaneously with medium pH changes. Membrane potential changes in parenchymal cells of the segments were also determined for chosen variants. The question of whether anion transport is involved in auxin-induced growth of maize coleoptile segments was primarily studied using anion channel blockers [anthracene-9-carboxylic acid (A-9-C) and 4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid (DIDS)]. In addition, experiments in which KCl was replaced by KNO3 were also performed. Both anion channel blockers, added at 0·1 mm, diminished indole-3-acetic acid (IAA)-induced elongation growth by ~30 %. Medium pH changes measured simultaneously with growth indicated that while DIDS stopped IAA-induced proton extrusion, A-9-C diminished it by only 50 %. Addition of A-9-C to medium containing 1 mm KCl did not affect the characteristic kinetics of IAA-induced membrane potential changes, while in the presence of 10 mm KCl the channel blocker stopped IAA-induced membrane hyperpolarization. Replacement of KCl with KNO3 significantly decreased IAA-induced growth and inhibited proton extrusion. In contrast to the KCl concentration, the concentration of KNO3 did not affect the growth-stimulatory effect of IAA. For comparison, the effects of the cation channel blocker tetraethylammonium chloride (TEA-Cl) on IAA-induced growth and proton extrusion were also determined. TEA

  6. Simulating changes in cropping practices in conventional and glyphosate-resistant maize. II. Weed impacts on crop production and biodiversity.

    Science.gov (United States)

    Colbach, Nathalie; Darmency, Henri; Fernier, Alice; Granger, Sylvie; Le Corre, Valérie; Messéan, Antoine

    2017-05-01

    Overreliance on the same herbicide mode of action leads to the spread of resistant weeds, which cancels the advantages of herbicide-tolerant (HT) crops. Here, the objective was to quantify, with simulations, the impact of glyphosate-resistant (GR) weeds on crop production and weed-related wild biodiversity in HT maize-based cropping systems differing in terms of management practices. We (1) simulated current conventional and probable HT cropping systems in two European regions, Aquitaine and Catalonia, with the weed dynamics model FLORSYS; (2) quantified how much the presence of GR weeds contributed to weed impacts on crop production and biodiversity; (3) determined the effect of cultural practices on the impact of GR weeds and (4) identified which species traits most influence weed-impact indicators. The simulation study showed that during the analysed 28 years, the advent of glyphosate resistance had little effect on plant biodiversity. Glyphosate-susceptible populations and species were replaced by GR ones. Including GR weeds only affected functional biodiversity (food offer for birds, bees and carabids) and weed harmfulness when weed effect was initially low; when weed effect was initially high, including GR weeds had little effect. The GR effect also depended on cultural practices, e.g. GR weeds were most detrimental for species equitability when maize was sown late. Species traits most harmful for crop production and most beneficial for biodiversity were identified, using RLQ analyses. None of the species presenting these traits belonged to a family for which glyphosate resistance was reported. An advice table was built; the effects of cultural practices on crop production and biodiversity were synthesized, explained, quantified and ranked, and the optimal choices for each management technique were identified.

  7. A Histological Study of Aspergillus flavus Colonization of Wound Inoculated Maize Kernels of Resistant and Susceptible Maize Hybrids in the Field

    Directory of Open Access Journals (Sweden)

    Gary L. Windham

    2018-04-01

    Full Text Available Aspergillus flavus colonization in developing kernels of maize single-cross hybrids resistant (Mp313E × Mp717 and susceptible (GA209 × T173 to aflatoxin accumulation was determined in the field over three growing seasons (2012–2014. Plants were hand pollinated, and individual kernels were inoculated with a needle dipped in a suspension of A. flavus conidia 21 days after pollination. Kernels were harvested at 1- to 2-day intervals from 1 to 21 days after inoculation (DAI. Kernels were placed in FAA fixative, dehydrated, embedded in paraffin, sectioned, and stained with toluidine blue. Kernels were also collected additional kernels for aflatoxin analyses in 2013 and 2014. At 2 DAI, A. flavus hyphae were observed among endosperm cells in the susceptible hybrid, but colonization of the endosperm in the resistant hybrid was limited to the wound site of the resistant hybrid. Sections of the scutellum of the susceptible hybrid were colonized by A. flavus by 5 DAI. Fungal growth was slower in the resistant hybrid compared to the susceptible hybrid. By 10 DAI, A. flavus had colonized a large section of the embryo in the susceptible hybrid; whereas in the resistant hybrid, approximately half of the endosperm had been colonized and very few cells in the embryo were colonized. Fungal colonization in some of the kernels of the resistant hybrid was slowed in the aleurone layer or at the endosperm-scutellum interface. In wounded kernels with intact aleurone layers, the fungus spread around the kernel between the pericarp and aleurone layer with minimal colonization of the endosperm. Aflatoxin B1 was first detected in susceptible kernel tissues 8 DAI in 2013 (14 μg/kg and 2014 (18 μg/kg. The resistant hybrid had significantly lower levels of aflatoxin accumulation compared to the susceptible hybrid at harvests 10, 21, and 28 DAI in 2013, and 20 and 24 DAI in 2014. Our study found differential A. flavus colonization of susceptible and resistant kernel

  8. Aflatoxins and fumonisin contamination of marketed maize, maize ...

    African Journals Online (AJOL)

    Aflatoxins and fumonisin contamination of marketed maize, maize bran and maize used as animal feed in northern ... PROMOTING ACCESS TO AFRICAN RESEARCH ... African Journal of Food, Agriculture, Nutrition and Development.

  9. Quantitative trait loci mapping of western corn rootworm (Coleoptera: Chrysomelidae) host plant resistance in two populations of doubled haploid lines in maize (Zea mays L.)

    Science.gov (United States)

    Over the last 70 years, more than 12,000 maize accessions have been screened for their level of resistance to western corn rootworm, Diabrotica virgifera virgifera LeConte, larval feeding. Less than 1% of this germplasm was selected for initiating recurrent selection or other breeding programs. Sele...

  10. Chemical and nutritional values of maize and maize products ...

    African Journals Online (AJOL)

    Maize and maize products in selected grain markets within Kaduna, Nigeria, were obtained and investigated for proximate and mineral composition analysis using Atomic Absorption Spectrophotometer (AAS) and flame photometer. Proximate composition of maize and maize products were in the range of 11.6- 20 .0% ...

  11. Ammonium Bicarbonate Transport in Anion Exchange Membranes for Salinity Gradient Energy

    KAUST Repository

    Geise, Geoffrey M.

    2013-09-17

    Many salinity gradient energy technologies such as reverse electrodialysis (RED) rely on highly selective anion transport through polymeric anion exchange membranes. While there is considerable interest in using thermolytic solutions such as ammonium bicarbonate (AmB) in RED processes for closed-loop conversion of heat energy to electricity, little is known about membrane performance in this electrolyte. The resistances of two commercially available cation exchange membranes in AmB were lower than their resistances in NaCl. However, the resistances of commercially available anion exchange membranes (AEMs) were much larger in AmB than in NaCl, which would adversely affect energy recovery. The properties of a series of quaternary ammonium-functionalized poly(phenylene oxide) and Radel-based AEMs were therefore examined to understand the reasons for increased resistance in AmB to overcome this performance penalty due to the lower mobility of bicarbonate, 4.59 × 10-4 cm2/(V s), compared to chloride, 7.90 × 10-4 cm2/(V s) (the dilute aqueous solution mobility ratio of HCO3 - to Cl- is 0.58). Most membrane resistances were generally consistent with the dilute solution mobilities of the anions. For a few key samples, however, increased water uptake in AmB solution reduced the ionic resistance of the polymer compared to its resistance in NaCl solution. This increased water uptake was attributed to the greater hydration of the bicarbonate ion compared to the chloride ion. The increased resistance due to the use of bicarbonate as opposed to chloride ions in AEMs can therefore be mitigated by designing polymers that swell more in AmB compared to NaCl solutions, enabling more efficient energy recovery using AmB thermolytic solutions in RED. © 2013 American Chemical Society.

  12. Ammonium Bicarbonate Transport in Anion Exchange Membranes for Salinity Gradient Energy

    KAUST Repository

    Geise, Geoffrey M.; Hickner, Michael A.; Logan, Bruce E.

    2013-01-01

    Many salinity gradient energy technologies such as reverse electrodialysis (RED) rely on highly selective anion transport through polymeric anion exchange membranes. While there is considerable interest in using thermolytic solutions such as ammonium bicarbonate (AmB) in RED processes for closed-loop conversion of heat energy to electricity, little is known about membrane performance in this electrolyte. The resistances of two commercially available cation exchange membranes in AmB were lower than their resistances in NaCl. However, the resistances of commercially available anion exchange membranes (AEMs) were much larger in AmB than in NaCl, which would adversely affect energy recovery. The properties of a series of quaternary ammonium-functionalized poly(phenylene oxide) and Radel-based AEMs were therefore examined to understand the reasons for increased resistance in AmB to overcome this performance penalty due to the lower mobility of bicarbonate, 4.59 × 10-4 cm2/(V s), compared to chloride, 7.90 × 10-4 cm2/(V s) (the dilute aqueous solution mobility ratio of HCO3 - to Cl- is 0.58). Most membrane resistances were generally consistent with the dilute solution mobilities of the anions. For a few key samples, however, increased water uptake in AmB solution reduced the ionic resistance of the polymer compared to its resistance in NaCl solution. This increased water uptake was attributed to the greater hydration of the bicarbonate ion compared to the chloride ion. The increased resistance due to the use of bicarbonate as opposed to chloride ions in AEMs can therefore be mitigated by designing polymers that swell more in AmB compared to NaCl solutions, enabling more efficient energy recovery using AmB thermolytic solutions in RED. © 2013 American Chemical Society.

  13. Molecular breeding for developing drought tolerant and disease resistant maize in sub Saharan Africa

    Science.gov (United States)

    The International Maize and Wheat Improvement Center (CIMMYT), in collaboration with public and private partners, is working on developing and disseminating drought tolerant maize for sub Saharan Africa (SSA) using pedigree selection and molecular breeding. In this paper, we provide an overview of ...

  14. Mitigation of aflatoxin contamination in maize kernels is related to the metabolic alternation of reactive oxygen and nitrogen species by relative humidity

    Science.gov (United States)

    Environmental factors have been shown to be linked to exacerbated infection of maize kernels by Aspergillus flavus and subsequent aflatoxin contamination. Kernel resistance to aflatoxin contamination is associated with kernel water content and relative humidity during in vitro assays examining aflat...

  15. Inheritance of Cry1F resistance, cross-resistance and frequency of resistant alleles in Spodoptera frugiperda (Lepidoptera: Noctuidae).

    Science.gov (United States)

    Vélez, A M; Spencer, T A; Alves, A P; Moellenbeck, D; Meagher, R L; Chirakkal, H; Siegfried, B D

    2013-12-01

    Transgenic maize, Zea maize L., expressing the Cry1F protein from Bacillus thuringiensis has been registered for Spodoptera frugiperda (J. E. Smith) control since 2003. Unexpected damage to Cry1F maize was reported in 2006 in Puerto Rico and Cry1F resistance in S. frugiperda was documented. The inheritance of Cry1F resistance was characterized in a S. frugiperda resistant strain originating from Puerto Rico, which displayed >289-fold resistance to purified Cry1F. Concentration-response bioassays of reciprocal crosses of resistant and susceptible parental populations indicated that resistance is recessive and autosomal. Bioassays of the backcross of the F1 generation crossed with the resistant parental strain suggest that a single locus is responsible for resistance. In addition, cross-resistance to Cry1Aa, Cry1Ab, Cry1Ac, Cry1Ba, Cry2Aa and Vip3Aa was assessed in the Cry1F-resistant strain. There was no significant cross-resistance to Cry1Aa, Cry1Ba and Cry2Aa, although only limited effects were observed in the susceptible strain. Vip3Aa was highly effective against susceptible and resistant insects indicating no cross-resistance with Cry1F. In contrast, low levels of cross-resistance were observed for both Cry1Ab and Cry1Ac. Because the resistance is recessive and conferred by a single locus, an F1 screening assay was used to measure the frequency of Cry1F-resistant alleles from populations of Florida and Texas in 2010 and 2011. A total frequency of resistant alleles of 0.13 and 0.02 was found for Florida and Texas populations, respectively, indicating resistant alleles could be found in US populations, although there have been no reports of reduced efficacy of Cry1F-expressing plants.

  16. (MSV) resistant maize varieties for adaptation to a southern guinea

    African Journals Online (AJOL)

    STORAGESEVER

    2009-10-05

    Oct 5, 2009 ... African Journal of Biotechnology Vol. 8 (19), pp. ... the development of superior maize varieties for the southern guinea savanna ecology. Key words: Zea ... tional agricultural research systems have succeeded in converting ...

  17. traits and resistance to maize streak virus disease in kenya

    African Journals Online (AJOL)

    African Crop Science Journal, Vol. 14. No. 4, pp. ... Kenya Agricultural Research Institute, Muguga-South, P.O. Box 30148, Nairobi, Kenya .... streak disease has been identified in various maize recycling and development of pure-lines at.

  18. Performance of laying hens fed diets containing DAS-59122-7 maize grain compared with diets containing nontransgenic maize grain.

    Science.gov (United States)

    Jacobs, C M; Utterback, P L; Parsons, C M; Rice, D; Smith, B; Hinds, M; Liebergesell, M; Sauber, T

    2008-03-01

    An experiment using 216 Hy-Line W-36 pullets was conducted to evaluate transgenic maize grain containing the cry34Ab1 and cry35Ab1 genes from a Bacillus thuringiensis (Bt) strain and the phosphinothricin ace-tyltransferase (pat) gene from Streptomyces viridochromogenes. Expression of the cry34Ab1 and cry35Ab1 genes confers resistance to corn rootworms, and the pat gene confers tolerance to herbicides containing glufosinate-ammonium. Pullets (20 wk of age) were placed in cage lots (3 hens/cage, 2 cages/lot) and were randomly assigned to 1 of 3 corn-soybean meal dietary treatments (12 lots/treatment) formulated with the following maize grains: near-isogenic control (control), conventional maize, and transgenic test corn line 59122 containing event DAS-59122-7. Differences between 59122 and control group means were evaluated with statistical significance at P < 0.05. Body weight and gain, egg production, egg mass, and feed efficiency for hens fed the 59122 corn were not significantly different from the respective values for hens fed diets formulated with control maize grain. Egg component weights, Haugh unit measures, and egg weight class distribution were similar regardless of the corn source. This research indicates that performance of hens fed diets containing 59122 maize grain, as measured by egg production and egg quality, was similar to that of hens fed diets formulated with near-isogenic corn grain.

  19. HvALMT1 from barley is involved in the transport of organic anions.

    Science.gov (United States)

    Gruber, Benjamin D; Ryan, Peter R; Richardson, Alan E; Tyerman, Stephen D; Ramesh, Sunita; Hebb, Diane M; Howitt, Susan M; Delhaize, Emmanuel

    2010-03-01

    Members of the ALMT gene family contribute to the Al(3+) resistance of several plant species by facilitating malate efflux from root cells. The first member of this family to be cloned and characterized, TaALMT1, is responsible for most of the natural variation of Al(3+) resistance in wheat. The current study describes the isolation and characterization of HvALMT1, the barley gene with the greatest sequence similarity to TaALMT1. HvALMT1 is located on chromosome 2H which has not been associated with Al(3+) resistance in barley. The relatively low levels of HvALMT1 expression detected in root and shoot tissues were independent of external aluminium or phosphorus supply. Transgenic barley plants transformed with the HvALMT1 promoter fused to the green fluorescent protein (GFP) indicated that expression of HvALMT1 was relatively high in stomatal guard cells and in root tissues containing expanding cells. GFP fused to the C-terminus of the full HvALMT1 protein localized to the plasma membrane and motile vesicles within the cytoplasm. HvALMT1 conferred both inward and outward currents when expressed in Xenopus laevis oocytes that were bathed in a range of anions including malate. Both malate uptake and efflux were confirmed in oocyte assays using [(14)C]malate as a radiotracer. It is suggested that HvALMT1 functions as an anion channel to facilitate organic anion transport in stomatal function and expanding cells.

  20. Intercropping Maize With Legumes for Sustainable Highland Maize Production

    Directory of Open Access Journals (Sweden)

    Adirek Punyalue

    2018-02-01

    Full Text Available Residue burning to prepare soil for maize growing deprives the soil of both protective cover and organic matter, and it exacerbates environmental issues such as Southeast Asia's haze problem. This paper reports on a study that evaluated the effectiveness of maize/legume intercropping as an alternative to maize cultivation with residue burning. Cowpea (Vigna unguiculata, mung bean (V. radiata, rice bean (V. umbellata, and lablab (Lablab purpureus were sown into a standing maize crop 30 days before harvest, and the results were compared with a maize crop grown using residue burning as the method for land preparation at Pang Da Agricultural Station in Chiang Mai, Thailand, in a replicated trial conducted over 3 growing seasons from 2012 to 2014. Intercropping increased maize grain yield by 31–53% and left 70–170% more residue containing 113–230% more nitrogen than the maize sown after residue burning, depending on the legume, and decreased weed dry weight by two-thirds after 2 seasons. Soil biodiversity was enriched by the intercrops, with a doubling in the spore density of arbuscular mycorrhizal fungi in the root-zone soil and increased abundance, diversity (Shannon index, and richness of the soil macrofauna. The abundance of soil animals increased with crop residue dry weight (r = 0.90, P < 0.05 and nitrogen content (r = 0.98, P < 0.01. The effect of intercropping on maize grain yield and accumulation of residue and nitrogen were then confirmed in a participatory experiment involving farmers in 2 highland villages in the Phrao and Chiang Dao districts of Chiang Mai Province with maize and rice bean in 2015. The effects of maize/legume intercropping—increased nitrogen accumulation and crop residue, enhanced soil biodiversity, suppression of weeds, and protection of the soil surface, which enabled the maize to be sown without land clearing with fire—should all contribute to sustainable highland maize production.

  1. A review on important maize diseases and their management in Nepal

    Directory of Open Access Journals (Sweden)

    Subash Subedi

    2015-12-01

    Full Text Available In Nepal, maize ranks second after rice both in area and production. In recent years, maize area and production has shown a steady increase, but productivity has been low (2.46 t/ha. The major maize producing regions in Nepal are mid hill (72.85%, terai (17.36% and high hill (9.79% respectively. A literature review was carried out to explore major maize diseases and their management in Nepal. The omnipresent incidence of diseases at the pre harvest stage has been an important bottleneck in increasing production. Till now, a total of 78 (75 fungal and 3 bacterial species are pathogenic to maize crop in Nepal. The major and economically important maize diseases reported are Gray leaf spot, Northern leaf blight, Southern leaf Blight, Banded leaf and sheath blight, Ear rot, Stalk rot, Head smut, Common rust, Downy mildew and Brown spot. Information on bacterial and virus diseases, nematodes and yield loss assessment is also given. Description of the major maize diseases, their causal organisms, distribution, time and intensity of disease incidence, symptoms, survival, spreads, environmental factors for disease development, yield losses and various disease management strategies corresponded to important maize diseases of Nepal are gathered and compiled thoroughly from the available publications. Concerted efforts of NARC commodity programs, divisions, ARS and RARS involving research on maize pathology and their important outcomes are mentioned. The use of disease management methods focused on host resistance has also been highlighted.

  2. Genetic characterization of early maturing maize hybrids (Zea mays L. obtained by protein and RAPD markers

    Directory of Open Access Journals (Sweden)

    Bauer Iva

    2005-01-01

    Full Text Available Knowledge of maize germplasm genetic diversity is important for planning breeding programmes, germplasm conservation per se etc. Genetic variability of maize hybrids grown in the fields is also very important because genetic uniformity implies risks of genetic vulnerability to stress factors and can cause great losts in yield. Early maturing maize hybrids are characterized by shorter vegetation period and they are grown in areas with shorter vegetation season. Because of different climatic conditions in these areas lines and hybrids are developed with different features in respect to drought resistance and disease resistance. The objective of our study was to characterize set of early maturing maize hybrids with protein and RAPD markers and to compare this clasification with their pedigree information. RAPD markers gave significantly higher rate of polymorphism than protein markers. Better corelation was found among pedigree information and protein markers.

  3. Complete sequence and diversity of a maize-associated Polerovirus in East Africa

    Science.gov (United States)

    Since 2011-2012, Maize lethal necrosis (MLN) has emerged in East Africa, causing massive yield loss and propelling research to identify viruses and virus populations present in maize. As expected, next generation sequencing (NGS) has revealed diverse and abundant viruses from the family Potyviridae,...

  4. Identification of quantitative trait Loci for resistance to southern leaf blight and days to anthesis in a maize recombinant inbred line population.

    Science.gov (United States)

    Balint-Kurti, P J; Krakowsky, M D; Jines, M P; Robertson, L A; Molnár, T L; Goodman, M M; Holl, J B

    2006-10-01

    ABSTRACT A recombinant inbred line population derived from a cross between the maize lines NC300 (resistant) and B104 (susceptible) was evaluated for resistance to southern leaf blight (SLB) disease caused by Cochliobolus heterostrophus race O and for days to anthesis in four environments (Clayton, NC, and Tifton, GA, in both 2004 and 2005). Entry mean and average genetic correlations between disease ratings in different environments were high (0.78 to 0.89 and 0.9, respectively) and the overall entry mean heritability for SLB resistance was 0.89. When weighted mean disease ratings were fitted to a model using multiple interval mapping, seven potential quantitative trait loci (QTL) were identified, the two strongest being on chromosomes 3 (bin 3.04) and 9 (bin 9.03-9.04). These QTL explained a combined 80% of the phenotypic variation for SLB resistance. Some time-point-specific SLB resistance QTL were also identified. There was no significant correlation between disease resistance and days to anthesis. Six putative QTL for time to anthesis were identified, none of which coincided with any SLB resistance QTL.

  5. The Importance of Maize Management on Dung Beetle Communities in Atlantic Forest Fragments.

    Directory of Open Access Journals (Sweden)

    Renata Calixto Campos

    Full Text Available Dung beetle community structures changes due to the effects of destruction, fragmentation, isolation and decrease in tropical forest area, and therefore are considered ecological indicators. In order to assess the influence of type of maize cultivated and associated maize management on dung beetle communities in Atlantic Forest fragments surrounded by conventional and transgenic maize were evaluated 40 Atlantic Forest fragments of different sizes, 20 surrounded by GM maize and 20 surrounded by conventional maize, in February 2013 and 2014 in Southern Brazil. After applying a sampling protocol in each fragment (10 pitfall traps baited with human feces or carrion exposed for 48 h, a total of 3454 individuals from 44 species were captured: 1142 individuals from 38 species in GM maize surrounded fragments, and 2312 from 42 species in conventional maize surrounded fragments. Differences in dung beetle communities were found between GM and conventional maize communities. As expected for fragmented areas, the covariance analysis showed a greater species richness in larger fragments under both conditions; however species richness was greater in fragments surrounded by conventional maize. Dung beetle structure in the forest fragments was explained by environmental variables, fragment area, spatial distance and also type of maize (transgenic or conventional associated with maize management techniques. In Southern Brazil's scenario, the use of GM maize combined with associated agricultural management may be accelerating the loss of diversity in Atlantic Forest areas, and consequently, important ecosystem services provided by dung beetles may be lost.

  6. The Importance of Maize Management on Dung Beetle Communities in Atlantic Forest Fragments.

    Science.gov (United States)

    Campos, Renata Calixto; Hernández, Malva Isabel Medina

    2015-01-01

    Dung beetle community structures changes due to the effects of destruction, fragmentation, isolation and decrease in tropical forest area, and therefore are considered ecological indicators. In order to assess the influence of type of maize cultivated and associated maize management on dung beetle communities in Atlantic Forest fragments surrounded by conventional and transgenic maize were evaluated 40 Atlantic Forest fragments of different sizes, 20 surrounded by GM maize and 20 surrounded by conventional maize, in February 2013 and 2014 in Southern Brazil. After applying a sampling protocol in each fragment (10 pitfall traps baited with human feces or carrion exposed for 48 h), a total of 3454 individuals from 44 species were captured: 1142 individuals from 38 species in GM maize surrounded fragments, and 2312 from 42 species in conventional maize surrounded fragments. Differences in dung beetle communities were found between GM and conventional maize communities. As expected for fragmented areas, the covariance analysis showed a greater species richness in larger fragments under both conditions; however species richness was greater in fragments surrounded by conventional maize. Dung beetle structure in the forest fragments was explained by environmental variables, fragment area, spatial distance and also type of maize (transgenic or conventional) associated with maize management techniques. In Southern Brazil's scenario, the use of GM maize combined with associated agricultural management may be accelerating the loss of diversity in Atlantic Forest areas, and consequently, important ecosystem services provided by dung beetles may be lost.

  7. Breeding of maize types with specific traits at the Maize Research Institute, Zemun Polje

    Directory of Open Access Journals (Sweden)

    Pajić Zorica

    2007-01-01

    Full Text Available Maize is primarily grown as an energy crop, but the use of different specific versions, such as high-oil maize, high-lysine maize, waxy maize, white-seeded maize, popping maize and sweet maize, is quite extensive. Speciality maize, due to its traits and genetic control of these traits, requires a particular attention in handling breeding material during the processes of breeding. It is especially related to prevention of uncontrolled pollination. In order to provide successful selection for a certain trait, the following specific procedures in evaluation of the trait are necessary: the estimation of a popping volume and flake quality in popping maize; the determination of sugars and harvest maturity in sweet maize; the determination of oil in selected samples of high-oil maize types, and so forth. Breeding programmes for speciality maize, except high-amylose maize, have been implemented at the Maize Research Institute, Zemun Polje, Belgrade, for the last 45 years. A great number of high-yielding sweet maize hybrids, popping maize, high-oil and high-lysine, flint and white-seeded maize hybrids were developed during this 45-year period. Auspicious selection and breeding for these traits is facilitated by the abundant genetic variability and technical and technological possibilities necessary for successful selection.

  8. Farmers' preferences for maize attributes in eastern and western

    African Journals Online (AJOL)

    ACSS

    African Crop Science Journal by African Crop Science Society is licensed ... Maize (Zea mays L.) is an important staple food crop in Uganda and is emerging as a cash crop for smallholder .... colour, grain size, pest and disease resistance.

  9. Effects of Bt-maize material on the life cycle of the land snail Cantareus aspersus

    DEFF Research Database (Denmark)

    Kramarz, Paulina; de Vaufleury, Annette; Gimbert, Frédéric

    2009-01-01

    ). For snails not previously exposed to Bt material, hatchability of eggs was similar in the soils tested. The outcome of the experiments indicates that, in growing snails, long-term exposure is needed to reveal an effect of Bt-maize. The hazard analysis of Bt-maize which we performed, based on a worst......Insect resistant Bt-maize (MON 810) expresses active Cry1Ab endotoxin derived from Bacillus thuringiensis (Bt). Snails constitute non-target soil species potentially exposed to Bt-toxin through consumption of plant material and soil in fields where transgenic plants have been grown. We studied...... the effect of the Cry1Ab toxin on survival, growth and egg hatchability of the snail Cantareus aspersus. From the age of 4 to 88 weeks, snails were fed either powdered Bt-maize or non-Bt-maize and exposed to soil samples collected after harvesting either the Bt-maize or non-Bt-maize. We applied four...

  10. Root-Expressed Maize Lipoxygenase 3 Negatively Regulates Induced Systemic Resistance to Colletotrichum graminicola in Shoots

    Directory of Open Access Journals (Sweden)

    Nasie eConstantino

    2013-12-01

    Full Text Available We have previously reported that disruption of a maize root-expressed 9-lipoxygenase (9-LOX gene, ZmLOX3, results in dramatic increase in resistance to diverse leaf and stalk pathogens. Despite evident economic significance of these findings, the mechanism behind this increased resistance remained elusive. In this study, we show that increased resistance of the lox3-4 mutants is due to constitutive activation of induced systemic resistance (ISR signaling. We showed that ZmLOX3 lacked expression in leaves in response to anthracnose leaf blight pathogen Colletotrichum graminicola, but was expressed constitutively in the roots, thus prompting our hypothesis: the roots of lox3-4 mutants are the source of increased resistance in leaves. Supporting this hypothesis, treatment of wild-type plants (WT with xylem sap of lox3-4 mutant induced resistance to C. graminicola to the levels comparable to those observed in lox3-4 mutant. Moreover, treating mutants with the sap collected from WT plants partially restored the susceptibility to C. graminicola. lox3-4 mutants showed primed defense responses upon infection, which included earlier and greater induction of defense-related PAL and GST genes compared to WT. In addition to the greater expression of the octadecanoid pathway genes, lox3-4 mutant responded earlier and with a greater accumulation of H2O2 in response to C. graminicola infection or treatment with alamethicin. These findings suggest that lox3-4 mutants display constitutive ISR-like signaling. In support of this idea, root colonization by Trichoderma virens strain GV29-8 induced the same level of disease resistance in WT as the treatment with the mutant sap, but had no additional resistance effect in lox3-4 mutant. While treatment with T. virens GV29 strongly and rapidly suppressed ZmLOX3 expression in hydroponically grown WT roots, T. virens Δsml mutant, which is deficient in ISR induction, was unable to suppress expression of ZmLOX3, thus

  11. Frequency of Cry1F resistance alleles in Spodoptera frugiperda (Lepidoptera: Noctuidae) in Brazil.

    Science.gov (United States)

    Farias, Juliano R; Andow, David A; Horikoshi, Renato J; Bernardi, Daniel; Ribeiro, Rebeca da S; Nascimento, Antonio Rb do; Santos, Antonio C Dos; Omoto, Celso

    2016-12-01

    The frequency of resistance alleles is a major factor influencing the rate of resistance evolution. Here, we adapted the F 2 screen procedure for Spodoptera frugiperda (J. E. Smith) with a discriminating concentration assay, and extended associated statistical methods to estimate the frequency of resistance to Cry1F protein in S. frugiperda in Brazil when resistance was not rare. We show that F 2 screen is efficient even when the resistance frequency is 0.250. It was possible to screen 517 isoparental lines from 12 populations sampled in five states of Brazil during the first half of 2012. Western Bahia had the highest allele frequency of Cry1F resistance, 0.192, with a 95% confidence interval (CI) between 0.163 and 0.220. All other states had a similar and lower frequency varying from 0.042 in Paraná to 0.080 in Mato Grosso do Sul. The high frequency in western Bahia may be related to year-round availability of maize, the high population density of S. frugiperda, the lack of refuges and the high adoption rate of Cry1F maize. Cry1F resistance alleles were not rare and occurred at frequencies that have already compromised the useful life of TC1507 maize in western Bahia. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  12. MRP3, an organic anion transporter able to transport anti-cancer drugs

    OpenAIRE

    Kool, Marcel; van der Linden, Marcel; de Haas, Marcel; Scheffer, George L.; de Vree, J. Marleen L.; Smith, Alexander J.; Jansen, Gerrit; Peters, Godefridus J.; Ponne, Nico; Scheper, Rik J.; Elferink, Ronald P. J. Oude; Baas, Frank; Borst, Piet

    1999-01-01

    The human multidrug-resistance protein (MRP) gene family contains at least six members: MRP1, encoding the multidrug-resistance protein; MRP2 or cMOAT, encoding the canalicular multispecific organic anion transporter; and four homologs, called MRP3, MRP4, MRP5, and MRP6. In this report, we characterize MRP3, the closest homolog of MRP1. Cell lines were retrovirally transduced with MRP3 cDNA, and new monoclonal antibodies specific for MRP3 were generated. We show that MRP3 is an organic anion ...

  13. Breeding of maize types with specific traits at the Maize Research Institute, Zemun Polje

    OpenAIRE

    Pajić Zorica

    2007-01-01

    Maize is primarily grown as an energy crop, but the use of different specific versions, such as high-oil maize, high-lysine maize, waxy maize, white-seeded maize, popping maize and sweet maize, is quite extensive. Speciality maize, due to its traits and genetic control of these traits, requires a particular attention in handling breeding material during the processes of breeding. It is especially related to prevention of uncontrolled pollination. In order to provide successful selection for a...

  14. Cry1F resistance among lepidopteran pests: a model for improved resistance management?

    Science.gov (United States)

    Vélez, Ana M; Vellichirammal, Neetha Nanoth; Jurat-Fuentes, Juan Luis; Siegfried, Blair D

    2016-06-01

    The Cry1Fa protein from the bacterium Bacillus thuringiensis (Bt) is known for its potential to control lepidopteran pests, especially through transgenic expression in maize and cotton. The maize event TC1507 expressing the cry1Fa toxin gene became commercially available in the United States in 2003 for the management of key lepidopteran pests including the European corn borer, Ostrinia nubilalis, and the fall armyworm, Spodoptera frugiperda. A high-dose/refuge strategy has been widely adopted to delay evolution of resistance to event TC1507 and other transgenic Bt crops. Efficacy of this strategy depends on the crops expressing a high dose of the Bt toxin to targeted pests and adjacent refuges of non-Bt host plants serving as a source of abundant susceptible insects. While this strategy has proved effective in delaying O. nubilalis resistance, field-evolved resistance to event TC1507 has been reported in S. frugiperda populations in Puerto Rico, Brazil, and the southeastern United States. This paper examines available information on resistance to Cry1Fa in O. nubilalis and S. frugiperda and discusses how this information identifies opportunities to refine resistance management recommendations for Bt maize. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. Genetic Markers for Western Corn Rootworm Resistance to Bt Toxin

    OpenAIRE

    Flagel, Lex E.; Swarup, Shilpa; Chen, Mao; Bauer, Christopher; Wanjugi, Humphrey; Carroll, Matthew; Hill, Patrick; Tuscan, Meghan; Bansal, Raman; Flannagan, Ronald; Clark, Thomas L.; Michel, Andrew P.; Head, Graham P.; Goldman, Barry S.

    2015-01-01

    Western corn rootworm (WCR) is a major maize (Zea mays L.) pest leading to annual economic losses of more than 1 billion dollars in the United States. Transgenic maize expressing insecticidal toxins derived from the bacterium Bacillus thuringiensis (Bt) are widely used for the management of WCR. However, cultivation of Bt-expressing maize places intense selection pressure on pest populations to evolve resistance. Instances of resistance to Bt toxins have been reported in WCR. Developing genet...

  16. Mimicking the cell membrane: bio-inspired simultaneous functions with monovalent anion selectivity and antifouling properties of anion exchange membrane

    Science.gov (United States)

    Zhao, Yan; Liu, Huimin; Tang, Kaini; Jin, Yali; Pan, Jiefeng; der Bruggen, Bart Van; Shen, Jiangnan; Gao, Congjie

    2016-01-01

    A new bio-inspired method was applied in this study to simultaneously improve the monovalent anion selectivity and antifouling properties of anion exchange membranes (AEMs). Three-layer architecture was developed by deposition of polydopamine (PDA) and electro-deposition of N-O-sulfonic acid benzyl chitosan (NSBC). The innermost and outermost layers were PDA with different deposition time. The middle layer was prepared by NSBC. Fourier transform infrared spectroscopy and scanning electron microscopy confirmed that PDA and NSBC were successfully modified on the surfaces of AEMs. The contact angle of the membranes indicated an improved hydrophilicity of the modified membranes. A series of electrodialysis experiments in which Cl−/SO42− separation was studied, demonstrating the monovalent anion selectivity of the samples. The Cl−/SO42− permselectivity of the modified membranes can reach up to 2.20, higher than that of the commercial membrane (only 0.78) during 90 minutes in electrodialysis (ED). The increase value of the resistance of the membranes was also measured to evaluate the antifouling properties. Sodium dodecyl benzene sulfonate (SDBS) was used as the fouling material in the ED process and the membrane area resistance of modified membrane increase value of was only 0.08 Ωcm2 30 minutes later. PMID:27853255

  17. Mimicking the cell membrane: bio-inspired simultaneous functions with monovalent anion selectivity and antifouling properties of anion exchange membrane

    Science.gov (United States)

    Zhao, Yan; Liu, Huimin; Tang, Kaini; Jin, Yali; Pan, Jiefeng; der Bruggen, Bart Van; Shen, Jiangnan; Gao, Congjie

    2016-11-01

    A new bio-inspired method was applied in this study to simultaneously improve the monovalent anion selectivity and antifouling properties of anion exchange membranes (AEMs). Three-layer architecture was developed by deposition of polydopamine (PDA) and electro-deposition of N-O-sulfonic acid benzyl chitosan (NSBC). The innermost and outermost layers were PDA with different deposition time. The middle layer was prepared by NSBC. Fourier transform infrared spectroscopy and scanning electron microscopy confirmed that PDA and NSBC were successfully modified on the surfaces of AEMs. The contact angle of the membranes indicated an improved hydrophilicity of the modified membranes. A series of electrodialysis experiments in which Cl-/SO42- separation was studied, demonstrating the monovalent anion selectivity of the samples. The Cl-/SO42- permselectivity of the modified membranes can reach up to 2.20, higher than that of the commercial membrane (only 0.78) during 90 minutes in electrodialysis (ED). The increase value of the resistance of the membranes was also measured to evaluate the antifouling properties. Sodium dodecyl benzene sulfonate (SDBS) was used as the fouling material in the ED process and the membrane area resistance of modified membrane increase value of was only 0.08 Ωcm2 30 minutes later.

  18. Frequent Shifts in Aspergillus flavus Populations Associated with Maize Production in Sonora, Mexico.

    Science.gov (United States)

    Ortega-Beltran, A; Cotty, P J

    2018-03-01

    Aspergillus flavus frequently contaminates maize, a critical staple for billions of people, with aflatoxins. Diversity among A. flavus L morphotype populations associated with maize in Sonora, Mexico was assessed and, in total, 869 isolates from 83 fields were placed into 136 vegetative compatibility groups (VCGs) using nitrate-nonutilizing mutants. VCG diversity indices did not differ in four agroecosystems (AES) but diversity significantly differed among years. Frequencies of certain VCGs changed manyfold over single years in both multiple fields and multiple AES. Certain VCGs were highly frequent (>1%) in 2006 but frequencies declined repeatedly in each of the two subsequent years. Other VCGs that had low frequencies in 2006 increased in 2007 and subsequently declined. None of the VCGs were consistently associated with any AES. Fourteen VCGs were considered dominant in at least a single year. However, frequencies often varied significantly among years. Only 9% of VCGs were detected all 3 years whereas 66% were detected in only 1 year. Results suggest that the most realistic measurements of both genetic diversity and the frequency of A. flavus VCGs are obtained by sampling multiple locations in multiple years. Single-season sampling in many locations should not be substituted for sampling over multiple years.

  19. Use of benzimidazole agar plates to assess fall armyworm (Lepidoptera: Noctuidae) feeding on excised maize and sorghum leaves

    Science.gov (United States)

    The fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) is an economically significant pest of sorghum and maize. To screen sorghum and maize germplasm for resistance to fall armyworm feeding, field, greenhouse, or lab bioassays are often utilized individually or in combinatio...

  20. Growth and dry matter accumulation in drought resistant maize ( Zea ...

    African Journals Online (AJOL)

    growth, dry matter accumulation and yield characters of maize planted under the same environmental conditions. The trial was conducted during the 2010 wet season at Bagauda the Kano University of Technology (KUST) temporary research farm (11° 39° N, 08° 20° E).The treatments consisted of three sowing dates ...

  1. Thc6 protein, isolated from Trichoderma harzianum, can induce maize defense response against Curvularia lunata.

    Science.gov (United States)

    Fan, Lili; Fu, Kehe; Yu, Chuanjin; Li, Yingying; Li, Yaqian; Chen, Jie

    2015-05-01

    Mutant T66 was isolated from 450 mutants (constructed with Agrobacterium tumefaciens-mediated transformation method) of Trichoderma harzianum. Maize seeds coated with T66 were more susceptible to Curvularia lunata when compared with those coated with wild-type (WT) strain. The disease index of maize treated with T66 and WT were 62.5 and 42.1%, respectively. Further research showed T-DNA has inserted into the ORF of one gene, which resulted in the functional difference between WT and T66. The gene was cloned and named Thc6, which encodes a novel 327 amino acid protein. To investigate its function, we obtained knockout, complementation, and overexpression mutants of Thc6. Challenge inoculation studies suggested that the Thc6 overexpression mutant can reduce the disease index of maize inbred line Huangzao 4 against the leaf spot pathogen (C. lunata). Meanwhile, The Thc6 mutants were found to affect the resistance of maize inbred line Huangzao 4 against C. lunata by enhancing the activation of jasmonate-responsive genes expression. Liquid chromatography-mass spectrometry (LC-MS) data further confirmed that the concentration of jasmonate in the induced maize exhibits a parallel change tendency with the expression level of defense-related genes. Hence, the Thc6 gene could be participated in the induced resistance of maize inbred line Huangzao 4 against C. lunata infection through a jasmonic acid-dependent pathway. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Decomposition and fertilizing effects of maize stover and chromolaena odorata on maize yield

    International Nuclear Information System (INIS)

    Tetteh, F.M.; Safo, E.Y.; Quansah, C.

    2008-01-01

    The quality, rates of decomposition and the fertilizing effect of chromolaena odorata, and maize stover were determined in field experiments as surface application or buried in litter bags. Studies on the effect of plant materials of contrasting qualities (maize stover and C. odorata) applied sole (10 Mg ha -1 ) and mixed, on maize grain and biomass yield were also conducted on the Asuansi (Ferric Acrisol) soil series. Total nitrogen content of the residues ranged from 0.85% in maize stover to 3.50% in C. odorata. Organic carbon ranged from 34.90% in C. odorata to 48.50% in maize stover. Phosphorus ranged from 0.10% in maize stover to 0.76% in C. odorata. In the wet season, the decomposition rate constants (k) were 0.0319 day -1 for C. odorata, and 0.0081 for maize stover. In the dry season, the k values were 0.0083 for C. odorata, and 0.0072 day -1 for maize stover. Burying of the plant materials reduced the half-life (t 50 ) periods from 18 to 10 days for C. odorata, and 45 to 20 days for maize stover. Maize grain yield of 2556 kg ha -1 was obtained in sole C. odorata (10 Mg ha -1 ) compared with 2167 kg ha -1 for maize stover. Mixing of maize stover and C. odorata residues improved the nutrient content as well as nutrient release by the mixtures resulting in greater maize grain yields in the mixtures than the sole maize stover treatment. It is recommended that C. odorata be used as green manure, mulching or composting material to improve fertility. (au)

  3. Sibling species of cercospora associated with gray leaf spot of maize.

    Science.gov (United States)

    Wang, J; Levy, M; Dunkle, L D

    1998-12-01

    ABSTRACT Monoconidial isolates of the fungus causing gray leaf spot of maize were obtained from diseased leaves collected throughout the United States and analyzed for genetic variability at 111 amplified fragment length polymorphism (AFLP) loci. Cluster analysis revealed two very distinct groups of Cercospora zeae-maydis isolates. Both groups were found to be relatively uniform internally with an average genetic similarity among isolates of approximately 93 and 94%, respectively. The groups were separated from each other by a genetic distance of approximately 80%, a distance greater than that separating each group from the sorghum pathogen, C. sorghi (67 to 70%). Characteristics and dimensions of conidia and conid-iophores produced on infected plants or nutrient media were unreliable criteria for taxonomic differentiation of isolates composing the two groups of C. zeae-maydis. Nucleotide sequences of 5.8S ribosomal DNA (rDNA) and the internal transcribed spacer (ITS) regions were identical within each group but different between the two groups and different from C. sorghi. Restriction fragment length polymorphisms generated by digestion of the 5.8S rDNA and ITS regions with TaqI readily distinguished each group and C. sorghi. Isolates in one group were generally distributed throughout maize-producing regions of the United States; isolates in the other group were localized in the eastern third of the country. Both types were present in the same fields at some locations. The genetic distance based on AFLP profiles and different ITS nucleotide sequences between the two morphologically indistinguishable groups indicate that they are sibling species. Although it is unlikely that breeding for resistance to gray leaf spot will be confounded by local or regional variation in the pathogen, a vigilant approach is warranted, because two pathogenic species exist with unknown abilities to evolve new pathotypes.

  4. Increased mortality is predicted of Inachis io larvae caused by Bt-maize pollen in European farmland

    DEFF Research Database (Denmark)

    Holst, Niels; Lang, Andreas; Lövei, Gabor L

    2013-01-01

    A potential environmental risk of the field cultivation of insect-resistant (Bt-toxin expressing) transgenic maize (Zea mays) is the consumption of Bt-containing pollen by herbivorous larvae of butterflies (Lepidoptera). Maize is wind-pollinated, and at flowering time large amounts of pollen can...

  5. Proteomic and phytohormone analysis of the response of maize (Zea mays L. seedlings to sugarcane mosaic virus.

    Directory of Open Access Journals (Sweden)

    Liuji Wu

    Full Text Available BACKGROUND: Sugarcane mosaic virus (SCMV is an important virus pathogen in crop production, causing serious losses in grain and forage yields in susceptible cultivars. Control strategies have been developed, but only marginal successes have been achieved. For the efficient control of this virus, a better understanding of its interactions and associated resistance mechanisms at the molecular level is required. METHODOLOGY/PRINCIPAL FINDINGS: The responses of resistant and susceptible genotypes of maize to SCMV and the molecular basis of the resistance were studied using a proteomic approach based on two-dimensional polyacrylamide gel electrophoresis (2-DE and matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS/MS analysis. Ninety-six protein spots showed statistically significant differences in intensity after SCMV inoculation. The classification of differentially expressed proteins showed that SCMV-responsive proteins were mainly involved in energy and metabolism, stress and defense responses, and photosynthesis. Most of the proteins identified were located in chloroplasts, chloroplast membranes, and the cytoplasm. Analysis of changes in phytohormone levels after virus inoculation suggested that salicylic acid, abscisic acid, jasmonic acid, and azelaic acid may played important roles in the maize response to SCMV infection. CONCLUSIONS/SIGNIFICANCE: Among these identified proteins, 19 have not been identified previously as virus-responsive proteins, and seven were new and did not have assigned functions. These proteins may be candidate proteins for future investigation, and they may present new biological functions and play important roles in plant-virus interactions. The behavioural patterns of the identified proteins suggest the existence of defense mechanisms operating during the early stages of infection that differed in two genotypes. In addition, there are overlapping and specific phytohormone

  6. Genetic Dissection of Maize Embryonic Callus Regenerative Capacity Using Multi-Locus Genome-Wide Association Studies

    Directory of Open Access Journals (Sweden)

    Langlang Ma

    2018-04-01

    Full Text Available The regenerative capacity of the embryonic callus, a complex quantitative trait, is one of the main limiting factors for maize transformation. This trait was decomposed into five traits, namely, green callus rate (GCR, callus differentiating rate (CDR, callus plantlet number (CPN, callus rooting rate (CRR, and callus browning rate (CBR. To dissect the genetic foundation of maize transformation, in this study multi-locus genome-wide association studies (GWAS for the five traits were performed in a population of 144 inbred lines genotyped with 43,427 SNPs. Using the phenotypic values in three environments and best linear unbiased prediction (BLUP values, as a result, a total of 127, 56, 160, and 130 significant quantitative trait nucleotides (QTNs were identified by mrMLM, FASTmrEMMA, ISIS EM-BLASSO, and pLARmEB, respectively. Of these QTNs, 63 QTNs were commonly detected, including 15 across multiple environments and 58 across multiple methods. Allele distribution analysis showed that the proportion of superior alleles for 36 QTNs was <50% in 31 elite inbred lines. Meanwhile, these superior alleles had obviously additive effect on the regenerative capacity. This indicates that the regenerative capacity-related traits can be improved by proper integration of the superior alleles using marker-assisted selection. Moreover, a total of 40 candidate genes were found based on these common QTNs. Some annotated genes were previously reported to relate with auxin transport, cell fate, seed germination, or embryo development, especially, GRMZM2G108933 (WOX2 was found to promote maize transgenic embryonic callus regeneration. These identified candidate genes will contribute to a further understanding of the genetic foundation of maize embryonic callus regeneration.

  7. Advances in Maize Transformation Technologies and Development of Transgenic Maize.

    Science.gov (United States)

    Yadava, Pranjal; Abhishek, Alok; Singh, Reeva; Singh, Ishwar; Kaul, Tanushri; Pattanayak, Arunava; Agrawal, Pawan K

    2016-01-01

    Maize is the principal grain crop of the world. It is also the crop where genetic engineering has been employed to a great extent to improve its various traits. The ability to transform maize is a crucial step for application of gene technology in maize improvement. There have been constant improvements in the maize transformation technologies over past several years. The choice of genotype and the explant material to initiate transformation and the different types of media to be used in various stages of tissue culture can have significant impact on the outcomes of the transformation efforts. Various methods of gene transfer, like the particle bombardment, protoplast transformation, Agrobacterium -mediated, in planta transformation, etc., have been tried and improved over years. Similarly, various selection systems for retrieval of the transformants have been attempted. The commercial success of maize transformation and transgenic development is unmatched by any other crop so far. Maize transformation with newer gene editing technologies is opening up a fresh dimension in transformation protocols and work-flows. This review captures the various past and recent facets in improvement in maize transformation technologies and attempts to present a comprehensive updated picture of the current state of the art in this area.

  8. Radiation stability of anion-exchange resins based on epichlorohydrin and vinylpyridines

    International Nuclear Information System (INIS)

    Zainutdinov, S.S.; Dzhalilov, A.T.; Askarov, M.A.

    1983-01-01

    The vigorous development of nuclear technology and atomic energy and the hydrometallurgy of the rare and radioactive metals has made it necessary to create and use ion-exchange materials possessing a high resistance to the action of ionizing radiations and the temperature. In view of this, the necessity has arisen for obtaining ion-exchange materials possessing adequate radiation stability. The results of an investigation of the radiation stability of anion-exchange resins based on the products of spontaneous polymerization in the interaction of epichlorohydrin with vinylpyridines show that they possess higher radiation resistance than the industrial anion-exchange resin AN-31 used at the present time

  9. Evaluation of maize genotypes for Turcicum leaf blight (Exserohilum turcicum in Terai and inner terai of Nepal

    Directory of Open Access Journals (Sweden)

    Tirtha Raj Rijal

    2016-12-01

    Full Text Available Thirty maize genotypes in 2014-2015 at Dumarwana, Nijgadh, Keureni and Rampur and ten genotypes in 2015-2016 at Anandpur, Shitalnagar, Dumarwana, Nijgadh and Rampur were evaluated for resistance to Turcicum leaf blight (Exserohilum turcicum under farmers field conditions. The scale used for disease severity ranged from 1-5 scale based on the proportionate leaf area affected by the disease. The combined analysis over locations in 2014-2015 showed that among the 30 genotypes 25 genotypes were resistant (1.0-2.0 scale, and 5 genotypes were moderately resistant (2.1-3.0 scale. Similarly the pooled analysis over locations in 2015-2016 showed that 7 genotypes were resistant (1.0-2.0 scale and 3 genotypes were moderately resistant (2.1-3.0 scale. The maize genotypes namely Z376-26, Z478-3, Z433-99, Z464-5, Z478-2, Z466-1, CAH1513, RML-95/RML-96, CAH1515, CAH1521, CAH1515, CAH151, CAH153, ZH114228 , Z376-9, Z466-3, Z376-5, RML-32/RML-17, RML-86/RML-96 and 900MGold were resistant with disease severity scale of 1.5 and with higher grain yield in both the years. Thus above genotypes were identified as promising sources of resistance against E. turcicum and they can be used to develop disease resistant and high yielding varieties to enhance maize productivity in terai and inner terai of Nepal.

  10. Status of maize stalk rot complex in western belts of Nepal and its integrated management

    Directory of Open Access Journals (Sweden)

    Subash Subedi

    2016-12-01

    Full Text Available Maize stalk rot complex is becoming a serious threat for maize growing areas of Nepal. A field monitoring for maize stalk rot complex was done during crop season (August, 2016 covering 10 farmers field each of Surkhet, Banke, Dang, Chitwan and Nawalparasi districts. Maize crop showed highly susceptible reaction to the disease at western belts of Dang and susceptible reaction was marked in Chitwan and Nawalparasi districts while the disease effect was mild at Banke and Surkhet district. Most of the plant diseases managed successfully through the application of bio-control agents, host resistance, chemicals and other different cultural control methods. The result of field experiment conducted at Dang showed that all the treatments had significant (P≤0.05 effect on percent disease index (PDI and crop yield over farmers practice to control maize stalk rot. The higher percent disease control (52.36% and yield increase (40.29% were recorded from the plot sprayed with streptocyclin @ 2 g L-1 and insecticide (cypermethrin + chloropyrifos @ 2.5 ml L-1 of water during knee height and subsequent spray after 15 days interval as compared to farmers practice. Out of 30 genotypes, Rampur composit, Arun 2, Rampur 34, RamS03F08, TLBRS07F16 and Rampur 24 were found resistant against stalk rot complex with higher yield at Rampur Chitwan.

  11. An improved ternary vector system for Agrobacterium-mediated rapid maize transformation.

    Science.gov (United States)

    Anand, Ajith; Bass, Steven H; Wu, Emily; Wang, Ning; McBride, Kevin E; Annaluru, Narayana; Miller, Michael; Hua, Mo; Jones, Todd J

    2018-05-01

    A simple and versatile ternary vector system that utilizes improved accessory plasmids for rapid maize transformation is described. This system facilitates high-throughput vector construction and plant transformation. The super binary plasmid pSB1 is a mainstay of maize transformation. However, the large size of the base vector makes it challenging to clone, the process of co-integration is cumbersome and inefficient, and some Agrobacterium strains are known to give rise to spontaneous mutants resistant to tetracycline. These limitations present substantial barriers to high throughput vector construction. Here we describe a smaller, simpler and versatile ternary vector system for maize transformation that utilizes improved accessory plasmids requiring no co-integration step. In addition, the newly described accessory plasmids have restored virulence genes found to be defective in pSB1, as well as added virulence genes. Testing of different configurations of the accessory plasmids in combination with T-DNA binary vector as ternary vectors nearly doubles both the raw transformation frequency and the number of transformation events of usable quality in difficult-to-transform maize inbreds. The newly described ternary vectors enabled the development of a rapid maize transformation method for elite inbreds. This vector system facilitated screening different origins of replication on the accessory plasmid and T-DNA vector, and four combinations were identified that have high (86-103%) raw transformation frequency in an elite maize inbred.

  12. Potential of Using Maize Cobs in Pig Diets — A Review

    Directory of Open Access Journals (Sweden)

    A. T. Kanengoni

    2015-12-01

    Full Text Available The quest to broaden the narrow range of feed ingredients available to pig producers has prompted research on the use of low cost, unconventional feedstuffs, which are typically fibrous and abundant. Maize cobs, a by-product of a major cereal grown worldwide, have potential to be used as a pig feed ingredient. Presently, maize cobs are either dumped or burnt for fuel. The major challenge in using maize cobs in pig diets is their lignocellulosic nature (45% to 55% cellulose, 25% to 35% hemicellulose, and 20% to 30% lignin which is resistant to pigs’ digestive enzymes. The high fiber in maize cobs (930 g neutral detergent fiber/kg dry matter [DM]; 573 g acid detergent fiber/kg DM increases rate of passage and sequestration of nutrients in the fiber reducing their digestion. However, grinding, heating and fermentation can modify the structure of the fibrous components in the maize cobs and improve their utilization. Pigs can also extract up to 25% of energy maintenance requirements from fermentation products. In addition, dietary fiber improves pig intestinal health by promoting the growth of lactic acid bacteria, which suppress proliferation of pathogenic bacteria in the intestines. This paper reviews maize cob composition and the effect on digestibility of nutrients, intestinal microflora and growth performance and proposes the use of ensiling using exogenous enzymes to enhance utilization in diets of pigs.

  13. Corrosion of conductive polypyrrole: Effects of environmental factors, electrochemical stimulation, and doping anions

    International Nuclear Information System (INIS)

    Qi Kai; Qiu Yubing; Chen Zhenyu; Guo Xingpeng

    2012-01-01

    Highlights: ► Corrosive galvanic cells form on PPy film with the electrochemical reduction of O 2. ► Suitable electrochemical stimulation can inhibit the PPy’s corrosion. ► PPy film doped with larger sized anions has better corrosion resistance performance. - Abstract: The effects of environmental factors, electrochemical stimulation, and doping anions on the corrosion behaviour of conductive polypyrrole (PPy) films in alkaline aqueous media were studied with cyclic voltammetry, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. High concentrations of electrolyte, low dissolved oxygen and low temperatures enhance the stability of PPy. Polarising PPy at a negative potential inhibits its corrosion obviously. PPy doped with large counter anions shows better corrosion resistance than PPy doped with small counter ions. The possible mechanism involved in PPy corrosion process is discussed.

  14. MaizeGDB: The Maize Genetics and Genomics Database.

    Science.gov (United States)

    Harper, Lisa; Gardiner, Jack; Andorf, Carson; Lawrence, Carolyn J

    2016-01-01

    MaizeGDB is the community database for biological information about the crop plant Zea mays. Genomic, genetic, sequence, gene product, functional characterization, literature reference, and person/organization contact information are among the datatypes stored at MaizeGDB. At the project's website ( http://www.maizegdb.org ) are custom interfaces enabling researchers to browse data and to seek out specific information matching explicit search criteria. In addition, pre-compiled reports are made available for particular types of data and bulletin boards are provided to facilitate communication and coordination among members of the community of maize geneticists.

  15. Maize kernel evolution:From teosinte to maize

    Science.gov (United States)

    Maize is the most productive and highest value commodity in the US and around the world: over 1 billion tons were produced each year in 2013 and 2014. Together, maize, rice and wheat comprise over 60% of the world’s caloric intake, with wide regional variability in the importance of each crop. The i...

  16. Harnessing maize biodiversity

    Science.gov (United States)

    Maize is a remarkably diverse species, adapted to a wide range of climatic conditions and farming practices. The latitudinal range of maize is immense, ranging from 54°N in Alberta, Canada, to 45°S in the province of Chubut, Argentina. In terms of altitude, maize is cultivated from sea level to 4000...

  17. Refuge or reservoir? The potential impacts of the biofuel crop Miscanthus x giganteus on a major pest of maize.

    Directory of Open Access Journals (Sweden)

    Joseph L Spencer

    Full Text Available BACKGROUND: Interest in the cultivation of biomass crops like the C4 grass Miscanthus x giganteus (Miscanthus is increasing as global demand for biofuel grows. In the US, Miscanthus is promoted as a crop well-suited to the Corn Belt where it could be cultivated on marginal land interposed with maize and soybean. Interactions (direct and indirect of Miscanthus, maize, and the major Corn Belt pest of maize, the western corn rootworm, (Diabrotica virgifera virgifera LeConte, WCR are unknown. Adding a perennial grass/biomass crop to this system is concerning since WCR is adapted to the continuous availability of its grass host, maize (Zea mays. METHODOLOGY/PRINCIPAL FINDINGS: In a greenhouse and field study, we investigated WCR development and oviposition on Miscanthus. The suitability of Miscanthus for WCR development varied across different WCR populations. Data trends indicate that WCR populations that express behavioural resistance to crop rotation performed as well on Miscanthus as on maize. Over the entire study, total adult WCR emergence from Miscanthus (212 WCR was 29.6% of that from maize (717 WCR. Adult dry weight was 75-80% that of WCR from maize; female emergence patterns on Miscanthus were similar to females developing on maize. There was no difference in the mean no. of WCR eggs laid at the base of Miscanthus and maize in the field. CONCLUSIONS/SIGNIFICANCE: Field oviposition and significant WCR emergence from Miscanthus raises many questions about the nature of likely interactions between Miscanthus, maize and WCR and the potential for Miscanthus to act as a refuge or reservoir for Corn Belt WCR. Responsible consideration of the benefits and risks associated with Corn Belt Miscanthus are critical to protecting an agroecosystem that we depend on for food, feed, and increasingly, fuel. Implications for European agroecosystems in which Miscanthus is being proposed are also discussed in light of the WCR's recent invasion into Europe.

  18. Genome-wide association mapping of leaf metabolic profiles for dissecting complex traits in maize.

    Science.gov (United States)

    Riedelsheimer, Christian; Lisec, Jan; Czedik-Eysenberg, Angelika; Sulpice, Ronan; Flis, Anna; Grieder, Christoph; Altmann, Thomas; Stitt, Mark; Willmitzer, Lothar; Melchinger, Albrecht E

    2012-06-05

    The diversity of metabolites found in plants is by far greater than in most other organisms. Metabolic profiling techniques, which measure many of these compounds simultaneously, enabled investigating the regulation of metabolic networks and proved to be useful for predicting important agronomic traits. However, little is known about the genetic basis of metabolites in crops such as maize. Here, a set of 289 diverse maize inbred lines was genotyped with 56,110 SNPs and assayed for 118 biochemical compounds in the leaves of young plants, as well as for agronomic traits of mature plants in field trials. Metabolite concentrations had on average a repeatability of 0.73 and showed a correlation pattern that largely reflected their functional grouping. Genome-wide association mapping with correction for population structure and cryptic relatedness identified for 26 distinct metabolites strong associations with SNPs, explaining up to 32.0% of the observed genetic variance. On nine chromosomes, we detected 15 distinct SNP-metabolite associations, each of which explained more then 15% of the genetic variance. For lignin precursors, including p-coumaric acid and caffeic acid, we found strong associations (P values to ) with a region on chromosome 9 harboring cinnamoyl-CoA reductase, a key enzyme in monolignol synthesis and a target for improving the quality of lignocellulosic biomass by genetic engineering approaches. Moreover, lignin precursors correlated significantly with lignin content, plant height, and dry matter yield, suggesting that metabolites represent promising connecting links for narrowing the genotype-phenotype gap of complex agronomic traits.

  19. Unfulfilled farmer expectations: the case of the Insect Resistant Maize for Africa (IRMA project in Kenya

    Directory of Open Access Journals (Sweden)

    Mabeya Justin

    2012-11-01

    Full Text Available Abstract Background Maize is the most important staple food in Kenya; any reduction in production and yield therefore often becomes a national food security concern. To address the challenge posed by the maize stem borer, the Insect Resistant Maize for Africa (IRMA agricultural biotechnology public-private partnership (PPP project was launched in 1999. There were, however, pre-existing concerns regarding the use of genetic engineering in crop production and skepticism about private sector involvement. The purpose of this case study was to understand the role of trust in the IRMA partnership by identifying the challenges to, and practices for, building trust in the project. Methods Data were collected by conducting face-to-face, semi-structured interviews; reviewing publicly available project documents; and direct observations. The data were analyzed to generate recurring and emergent themes on how trust is understood and built among the partners in the IRMA project and between the project and the community. Results Clear and continued communication with stakeholders is of paramount importance to building trust, especially regarding competition among partners about project management positions; a lack of clarity on ownership of intellectual property rights (IPRs; and the influence of anti-genetic modification (GM organizations. Awareness creation about IRMA’s anticipated products raised the end users’ expectations, which were unfulfilled due to failure to deliver Bacillus thuringiensis (Bt-based products, thereby leading to diminished trust between the project and the community. Conclusions Four key issues have been identified from the results of the study. First, the inability to deliver the intended products to the end user diminished stakeholders’ trust and interest in the project. Second, full and honest disclosure of information by partners when entering into project agreements is crucial to ensuring progress in a project. Third

  20. Evaluation of stem borer resistance management strategies for Bt ...

    African Journals Online (AJOL)

    GREGORY

    2011-06-01

    Jun 1, 2011 ... cultivars were identified as cost-effective, flexible, easily adoptable and ... Key words: Refugia, cost-benefit analysis, Bt-maize, insect pest resistance management. ..... Refugia are part of stewardship plan for the Bt maize.

  1. EFSA Panel on Genetically Modified Organisms (GMO); Scientific Opinion on application (EFSAGMO- NL-2007-39) for the placing on the market of insect resistant and herbicide tolerant genetically modified maize MON89034 x MON88017 for food and feed uses, import and processing under Regulation (EC

    DEFF Research Database (Denmark)

    Sørensen, Ilona Kryspin

    This opinion reports on an evaluation of a risk assessment for placing on the market the genetically modified herbicide tolerant and insect resistant maize MON89034 x MON88017 for food and feed uses, import and processing. Conventional breeding methods were used in the production of maize MON89034...

  2. Anion channels: master switches of stress responses.

    Science.gov (United States)

    Roelfsema, M Rob G; Hedrich, Rainer; Geiger, Dietmar

    2012-04-01

    During stress, plant cells activate anion channels and trigger the release of anions across the plasma membrane. Recently, two new gene families have been identified that encode major groups of anion channels. The SLAC/SLAH channels are characterized by slow voltage-dependent activation (S-type), whereas ALMT genes encode rapid-activating channels (R-type). Both S- and R-type channels are stimulated in guard cells by the stress hormone ABA, which leads to stomatal closure. Besides their role in ABA-dependent stomatal movement, anion channels are also activated by biotic stress factors such as microbe-associated molecular patterns (MAMPs). Given that anion channels occur throughout the plant kingdom, they are likely to serve a general function as master switches of stress responses. Copyright © 2012 Elsevier Ltd. All rights reserved.

  3. Analysis of virtual water flows associated with the trade of maize in the SADC region: importance of scale

    Directory of Open Access Journals (Sweden)

    J. M. Dabrowski

    2009-10-01

    Full Text Available The concept of virtual water encourages a country to view agricultural crops in terms of the amount of water required to produce those crops, with a view to implementing trading policies that promote the saving of scarce water resources. Recently, increased attention has focussed on partitioning the virtual water content of crops into green and blue water (derived from rainfall and irrigation, respectively as the latter has higher opportunity costs associated with its use and therefore impacts directly on scarcity. Maize is the most important crop traded within the SADC region. South Africa is the largest producer and exporter of maize, with the majority of its exports destined for other SADC countries. In comparison to other SADC countries, South Africa produces maize relatively efficiently, with a low virtual water content and a high green (868 m3 t−1 to blue (117 m3 t−1 water ratio. The blue water content is however higher than for maize produced in all other SADC countries, with the exception of Namibia (211 m3 t−1. Current trade patterns therefore result in a net expenditure of blue water (66×106 m3, almost all of which is exported by South Africa (65×106 m3. South Africa is one of the most water scarce countries in the region and analysis of virtual water flows indicates that current SADC maize trading patterns are influenced by national productivity as opposed to water scarcity. The virtual water content of maize was estimated for each of South Africa's nineteen Water Management Area's (WMA and used as a proxy to represent water use efficiency for maize production. The virtual water content varied widely across all of the WMAs, ranging from 360 m3 t−1 in the Ustutu Mhlatuze to 1000 m3 t−1 in the Limpopo. A comparison of the virtual water content and production of maize

  4. Expression Patterns of Genes Involved in Ascorbate-Glutathione Cycle in Aphid-Infested Maize (Zea mays L.) Seedlings.

    Science.gov (United States)

    Sytykiewicz, Hubert

    2016-02-23

    Reduced forms of ascorbate (AsA) and glutathione (GSH) are among the most important non-enzymatic foliar antioxidants in maize (Zea mays L.). The survey was aimed to evaluate impact of bird cherry-oat aphid (Rhopalosiphum padi L.) or grain aphid (Sitobion avenae F.) herbivory on expression of genes related to ascorbate-glutathione (AsA-GSH) cycle in seedlings of six maize varieties (Ambrozja, Nana, Tasty Sweet, Touran, Waza, Złota Karłowa), differing in resistance to the cereal aphids. Relative expression of sixteen maize genes encoding isoenzymes of ascorbate peroxidase (APX1, APX2, APX3, APX4, APX5, APX6, APX7), monodehydroascorbate reductase (MDHAR1, MDHAR2, MDHAR3, MDHAR4), dehydroascorbate reductase (DHAR1, DHAR2, DHAR3) and glutathione reductase (GR1, GR2) was quantified. Furthermore, effect of hemipterans' attack on activity of APX, MDHAR, DHAR and GR enzymes, and the content of reduced and oxidized ascorbate and glutathione in maize plants were assessed. Seedling leaves of more resistant Z. mays varieties responded higher elevations in abundance of target transcripts. In addition, earlier and stronger aphid-triggered changes in activity of APX, MDHAR, DHAR and GR enzymes, and greater modulations in amount of the analyzed antioxidative metabolites were detected in foliar tissues of highly resistant Ambrozja genotype in relation to susceptible Tasty Sweet plants.

  5. Farmers’ desired traits and selection criteria for maize varieties and their implications for maize breeding: A case study from KwaZulu-Natal Province, South Africa

    Directory of Open Access Journals (Sweden)

    Julia Sibiya

    2013-08-01

    Full Text Available Adoption of hybrids and improved varieties has remained low in the smallholder farming sector of South Africa, despite maize being the staple food crop for the majority of households. The objective of this study was to establish preferred maize characteristics by farmers which can be used as selection criteria by maize breeders in crop improvement. Data were collected from three villages of a selected smallholder farming area in South Africa using a survey covering 300 households and participatory rural appraisal methodology. Results indicated a limited selection of maize varieties grown by farmers in the area compared to other communities in Africa. More than 97% of the farmers grew a local landrace called Natal-8-row or IsiZulu. Hybrids and improved open pollinated varieties were planted by less than 40% of the farmers. The Natal-8-row landrace had characteristics similar to landraces from eastern and southern Africa and closely resembled Hickory King, a landrace still popular in Southern Africa. The local landrace was preferred for its taste, recycled seed, tolerance to abiotic stresses and yield stability. Preferred characteristics of maize varieties were high yield and prolificacy, disease resistance, early maturity, white grain colour, and drying and shelling qualities. Farmers were willing to grow hybrids if the cost of seed and other inputs were affordable and their preferences were considered. Our results show that breeding opportunities exist for improving the farmers’ local varieties and maize breeders can take advantage of these preferred traits and incorporate them into existing high yielding varieties.

  6. The Reaction of some Maize Hybrids, Created at ARDS TURDA, to Fusarium spp. Infection

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    Laura ȘOPTEREAN

    2017-05-01

    Full Text Available The most important disease of maize in Romania are stalk and ear rot, which caused yield losses in average of 20%. The resistant hibrids represent one of the most efficient solution for reducing the field loses caused by Fusarium spp. on the maize (Nagy et al., 2006. Diseases caused by Fusarium spp. can affect the yield and grain quality of maize because of contamination with numerous mycotoxins produced by these fungi (Czembor et al., 2015. The purpose of this paper was to know more about the reaction of different maize hybrids to Fusarium and the evaluating the effect of ear rot on the yield ability and mycotoxins accumulation. The experiments carried out at ARDS Turda, during four years (2012-2015. The biological material was represented by 8 hybrids, from different maturity groups, tested in two infection conditions with Fusarium spp. (natural and artificial infections. The temperature and rainfalls of the four years of experiments corresponding to the vegetation of maize (april-september are influenced favourably the pathogenesis of stalk and ear rot caused by Fusarium spp. and a good discrimination of the resistance reaction of genotypes. Fusarium ear rot has significantly affected production capacity and chemical composition of corn hybrids tested. In conditions of artificial infection with Fusarium spp. was a decrease in the content of starch, fat and increased protein content compared with artificially inoculated variants. The quantity of fumonizin B1+B2 has reached to 5630 μg/kg in conditions of artificial infection. There are negative correlations between production capacity and degree of attack of fusarium ear rot; depending on the reacting genotypes tested increasing disease causes production decrease. The response of maize hybrids to Fusarium infection is influenced by infection and climatic conditions. These factors affect production both in terms of quantity and quality and accumulation of mycotoxins.

  7. Mice fed a high-fat diet supplemented with resistant starch display marked shifts in the liver metabolome concurrent with altered gut bacteria

    Science.gov (United States)

    High-amylose maize resistant starch type 2 (HAMRS2) is a fermentable dietary fiber known to alter the gut milieu, including the gut microbiota, which may explain reported effects of resistant starch to ameliorate obesity-associated metabolic dysfunction. Our working hypothesis is that HAMRS2-induced...

  8. Transcriptomic Profiling of the Maize (Zea mays L.) Leaf Response to Abiotic Stresses at the Seedling Stage.

    Science.gov (United States)

    Li, Pengcheng; Cao, Wei; Fang, Huimin; Xu, Shuhui; Yin, Shuangyi; Zhang, Yingying; Lin, Dezhou; Wang, Jianan; Chen, Yufei; Xu, Chenwu; Yang, Zefeng

    2017-01-01

    Abiotic stresses, including drought, salinity, heat, and cold, negatively affect maize ( Zea mays L.) development and productivity. To elucidate the molecular mechanisms of resistance to abiotic stresses in maize, RNA-seq was used for global transcriptome profiling of B73 seedling leaves exposed to drought, salinity, heat, and cold stress. A total of 5,330 differentially expressed genes (DEGs) were detected in differential comparisons between the control and each stressed sample, with 1,661, 2,019, 2,346, and 1,841 DEGs being identified in comparisons of the control with salinity, drought, heat, and cold stress, respectively. Functional annotations of DEGs suggested that the stress response was mediated by pathways involving hormone metabolism and signaling, transcription factors (TFs), very-long-chain fatty acid biosynthesis and lipid signaling, among others. Of the obtained DEGs (5,330), 167 genes are common to these four abiotic stresses, including 10 up-regulated TFs (five ERFs, two NACs, one ARF, one MYB, and one HD-ZIP) and two down-regulated TFs (one b-ZIP and one MYB-related), which suggested that common mechanisms may be initiated in response to different abiotic stresses in maize. This study contributes to a better understanding of the molecular mechanisms of maize leaf responses to abiotic stresses and could be useful for developing maize cultivars resistant to abiotic stresses.

  9. Advances in Improving Ukiriguru Composite B Maize ( Zea mays L ...

    African Journals Online (AJOL)

    S1 recurrent selection was carried out to improve grain yield, plant height, ear placement, resistance to lodging and other desirable agronomic traits in Ukiriguru composite B (UCB) maize variety. This paper presents the genetic gain and progress made in improving these traits through two cycles of selection. Three hundred ...

  10. Molecular investigations of the soil, rhizosphere and transgenic glufosinate-resistant rape and maize plants in combination with herbicide (Basta) application under field conditions.

    Science.gov (United States)

    Ernst, Dieter; Rosenbrock-Krestel, Hilkea; Kirchhof, Gudrun; Bieber, Evi; Giunaschwili, Nathela; Müller, Rüdiger; Fischbeck, Gerhard; Wagner, Tobias; Sandermann, Heinrich; Hartmann, Anton

    2008-01-01

    A field study was conducted during 1994 to 1998 on the Experimental Farm Roggenstein, near Fürstenfeldbruck, Bavaria, Germany to determine the effect of transgenic glufosinate-resistant rape in combination with the herbicide Basta [glufosinate-ammonium, phosphinothricin, ammonium (2RS)-2-amino-4-(methylphosphinato) butyric acid] application on soil microorganisms and the behaviour of the synthetic transgenic DNA in response to normal agricultural practice. No influence of Basta on microbial biomass could be detected. The phospholipid fatty acid analysis of soil extracts showed no difference between Basta application and mechanical weed control, whereas conventional herbicide application revealed a different pattern. Basta application resulted in a changed population of weeds with a selective effect for Viola arvensis. During senescence, transgenic rape DNA was degraded similar to endogenous control DNA. After ploughing the chopped plant material in the soil, transgenic as well as endogenous control DNA sequences could be detected for up to 4 weeks for rape and up to 7 months for maize, whereas PCR analysis of composted transgenic maize revealed the presence of the transgene over a period of 22 months.

  11. Mycoflora Of Maize Zea Maize At Different Locations In Hail Area-Saudi Arabia

    Directory of Open Access Journals (Sweden)

    Elham S. Dawood

    2015-06-01

    Full Text Available Abstract Zea maize is one of the main cereals produced in Hail area Saudi Arabia. The risk of mycotoxin contamination is related to mycoflora associated with corn kernel. This paper reports on isolation and identification of external and internal mycoflora of maize harvested in Hail area in 2006 2008. A mycological survey was carried out on 200 samples from two agricultural companies . Comparison between frequency and relative density of the prevalent genera and species was carried out. Genus Fusarium was the most prevalent component of the internal seed - borne mycoflora in the two companies Aspergillus spp. was the most prevalent genus as external seed borne mycoflora. The predominant species of the different genera were Fusarium moniliforrme Aspergillus flavus A. niger and Alternaria alternate.

  12. VIGOR TESTS ASSOCIATION AS AN ALTERNATIVE FOR PRECISE AND EFFICIENT ASSESSMENT OF MAIZE SEED QUALITY

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    MARCOS ALTOMANI NEVES DIAS

    2015-01-01

    Full Text Available This study aimed to associate two concepts of seed vigor testing, the aging and seedling growth using image analysis, providing a feasible and time-saving way to evaluate maize seed vigor in large scale. For this purpose, five seed lots with different vigor levels from two single hybrids were used. The seeds were characterized by moisture content, germination, seedling emergence, seedling emergence speed index, accelerated aging and cold tests. The treatments were composed by varying the accelerated aging periods (0, 24, 48, 72 and 96h and seedling growth periods (48 and 72h, before submitting the seedlings to image analysis for seedling root length measurement. Considering the results obtained, the adaptation of accelerated aging test by reducing the aging duration from 96h to 48h, and the replacement of the germination test by seedling root length measurement using image analysis could be considered a potential tool for maize seed vigor assessment. The treatments composed of 48h of seed aging followed by seedlings root length measurements using image analysis provided reliable data, compared to traditional vigor tests and it could be considered an efficient and timesaving approach, associating two different concepts of seed vigor analysis.

  13. Neonicotinoid insecticide residues in surface water and soil associated with commercial maize (corn fields in southwestern Ontario.

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    Arthur Schaafsma

    Full Text Available Neonicotinoid insecticides have come under scrutiny for their potential unintended effects on non-target organisms, particularly pollinators in agro-ecosystems. As part of a larger study of neonicotinoid residues associated with maize (corn production, 76 water samples within or around the perimeter of 18 commercial maize fields and neighbouring apiaries were collected in 5 maize-producing counties of southwestern Ontario. Residues of clothianidin (mean = 2.28, max. = 43.60 ng/mL and thiamethoxam (mean = 1.12, max. = 16.50 ng/mL were detected in 100 and 98.7% of the water samples tested, respectively. The concentration of total neonicotinoid residues in water within maize fields increased six-fold during the first five weeks after planting, and returned to pre-plant levels seven weeks after planting. However, concentrations in water sampled from outside the fields were similar throughout the sampling period. Soil samples from the top 5 cm of the soil profile were also collected in these fields before and immediately following planting. The mean total neonicotinoid residue was 4.02 (range 0.07 to 20.30 ng/g, for samples taken before planting, and 9.94 (range 0.53 to 38.98 ng/g, for those taken immediately after planting. Two soil samples collected from within an conservation area contained detectable (0.03 and 0.11 ng/g concentrations of clothianidin. Of three drifted snow samples taken, the drift stratum containing the most wind-scoured soil had 0.16 and 0.20 ng/mL mainly clothianidin in the melted snow. The concentration was at the limit of detection (0.02 ng/mL taken across the entire vertical profile. With the exception of one sample, water samples tested had concentrations below those reported to have acute, chronic or sublethal effects to honey bees. Our results suggest that neonicotinoids may move off-target by wind erosion of contaminated soil. These results are informative to risk assessment models for other non-target species in maize

  14. Neonicotinoid Insecticide Residues in Surface Water and Soil Associated with Commercial Maize (Corn) Fields in Southwestern Ontario

    Science.gov (United States)

    Schaafsma, Arthur; Limay-Rios, Victor; Baute, Tracey; Smith, Jocelyn; Xue, Yingen

    2015-01-01

    Neonicotinoid insecticides have come under scrutiny for their potential unintended effects on non-target organisms, particularly pollinators in agro-ecosystems. As part of a larger study of neonicotinoid residues associated with maize (corn) production, 76 water samples within or around the perimeter of 18 commercial maize fields and neighbouring apiaries were collected in 5 maize-producing counties of southwestern Ontario. Residues of clothianidin (mean = 2.28, max. = 43.60 ng/mL) and thiamethoxam (mean = 1.12, max. = 16.50 ng/mL) were detected in 100 and 98.7% of the water samples tested, respectively. The concentration of total neonicotinoid residues in water within maize fields increased six-fold during the first five weeks after planting, and returned to pre-plant levels seven weeks after planting. However, concentrations in water sampled from outside the fields were similar throughout the sampling period. Soil samples from the top 5 cm of the soil profile were also collected in these fields before and immediately following planting. The mean total neonicotinoid residue was 4.02 (range 0.07 to 20.30) ng/g, for samples taken before planting, and 9.94 (range 0.53 to 38.98) ng/g, for those taken immediately after planting. Two soil samples collected from within an conservation area contained detectable (0.03 and 0.11 ng/g) concentrations of clothianidin. Of three drifted snow samples taken, the drift stratum containing the most wind-scoured soil had 0.16 and 0.20 ng/mL mainly clothianidin in the melted snow. The concentration was at the limit of detection (0.02 ng/mL) taken across the entire vertical profile. With the exception of one sample, water samples tested had concentrations below those reported to have acute, chronic or sublethal effects to honey bees. Our results suggest that neonicotinoids may move off-target by wind erosion of contaminated soil. These results are informative to risk assessment models for other non-target species in maize agro

  15. Development of maizeSNP3072, a high-throughput compatible SNP array, for DNA fingerprinting identification of Chinese maize varieties.

    Science.gov (United States)

    Tian, Hong-Li; Wang, Feng-Ge; Zhao, Jiu-Ran; Yi, Hong-Mei; Wang, Lu; Wang, Rui; Yang, Yang; Song, Wei

    2015-01-01

    Single nucleotide polymorphisms (SNPs) are abundant and evenly distributed throughout the maize ( Zea mays L.) genome. SNPs have several advantages over simple sequence repeats, such as ease of data comparison and integration, high-throughput processing of loci, and identification of associated phenotypes. SNPs are thus ideal for DNA fingerprinting, genetic diversity analysis, and marker-assisted breeding. Here, we developed a high-throughput and compatible SNP array, maizeSNP3072, containing 3072 SNPs developed from the maizeSNP50 array. To improve genotyping efficiency, a high-quality cluster file, maizeSNP3072_GT.egt, was constructed. All 3072 SNP loci were localized within different genes, where they were distributed in exons (43 %), promoters (21 %), 3' untranslated regions (UTRs; 22 %), 5' UTRs (9 %), and introns (5 %). The average genotyping failure rate using these SNPs was only 6 %, or 3 % using the cluster file to call genotypes. The genotype consistency of repeat sample analysis on Illumina GoldenGate versus Infinium platforms exceeded 96.4 %. The minor allele frequency (MAF) of the SNPs averaged 0.37 based on data from 309 inbred lines. The 3072 SNPs were highly effective for distinguishing among 276 examined hybrids. Comparative analysis using Chinese varieties revealed that the 3072SNP array showed a better marker success rate and higher average MAF values, evaluation scores, and variety-distinguishing efficiency than the maizeSNP50K array. The maizeSNP3072 array thus can be successfully used in DNA fingerprinting identification of Chinese maize varieties and shows potential as a useful tool for germplasm resource evaluation and molecular marker-assisted breeding.

  16. Metabolic engineering of geranic acid in maize to achieve fungal resistance is compromised by novel glycosylation patterns.

    Science.gov (United States)

    Yang, Ting; Stoopen, Geert; Yalpani, Nasser; Vervoort, Jacques; de Vos, Ric; Voster, Alessandra; Verstappen, Francel W A; Bouwmeester, Harro J; Jongsma, Maarten A

    2011-07-01

    Many terpenoids are known to have antifungal properties and overexpression of these compounds in crops is a potential tool in disease control. In this study, 15 different mono- and sesquiterpenoids were tested in vitro against two major pathogenic fungi of maize (Zea mays), Colletotrichum graminicola and Fusarium graminearum. Among all tested terpenoids, geranic acid showed very strong inhibitory activity against both fungi (MICLippia dulcis under the control of a ubiquitin promoter. The volatile and non-volatile metabolite profiles of leaves from transgenic and control lines were compared. The headspaces collected from intact seedlings of transgenic and control plants were not significantly different, although detached leaves of transgenic plants emitted 5-fold more geranyl acetate compared to control plants. Non-targeted LC-MS profiling and LC-MS-MS identification of extracts from maize leaves revealed that the major significantly different non-volatile compounds were 2 geranic acid derivatives, a geraniol dihexose and 4 different types of hydroxyl-geranic acid-hexoses. A geranic acid glycoside was the most abundant, and identified by NMR as geranoyl-6-O-malonyl-β-d-glucopyranoside with an average concentration of 45μM. Fungal bioassays with C. graminicola and F. graminearum did not reveal an effect of these changes in secondary metabolite composition on plant resistance to either fungus. The results demonstrate that metabolic engineering of geraniol into geranic acid can rely on the existing default pathway, but branching glycosylation pathways must be controlled to achieve accumulation of the aglycones. Copyright © 2011 Elsevier Inc. All rights reserved.

  17. Susceptibility and aversion of Spodoptera frugiperda to Cry1F Bt maize and considerations for insect resistance management

    Science.gov (United States)

    Bacillus thuringiensis (Bt) maize was developed primarily for North American pests such as European corn borer (Ostrinia nubilalis Hubner). However, most Bt maize products also are cultivated outside of North America, where the primary pests are different and often have lower susceptibility to Bt to...

  18. Assessment of maize stem borer damage on hybrid maize varieties in Chitwan, Nepal

    OpenAIRE

    Buddhi Bahadur Achhami; Santa Bahadur BK; Ghana Shyam Bhandari

    2015-01-01

    Maize is the second most important cereal crop in Nepal. However, national figure of grain production still remains below than the world's average grain production per unit area. Thus, this experiment was designed to determine the suitable time of maize planting, and to assess the peak period of one of the major insects, maize stem borer, in Chitwan condition. The results showed that plant damage percentage as per the maize planting month varies significantly, and the average plant damage per...

  19. Risk Adjusted Production Efficiency of Maize Farmers in Ethiopia: Implication for Improved Maize Varieties Adoption

    Directory of Open Access Journals (Sweden)

    Sisay Diriba Lemessa

    2017-09-01

    Full Text Available This study analyzes the technical efficiency and production risk of 862 maize farmers in major maize producing regions of Ethiopia. It employs the stochastic frontier approach (SFA to estimate the level of technical efficiencies of stallholder farmers. The stochastic frontier approach (SFA uses flexible risk properties to account for production risk. Thus, maize production variability is assessed from two perspectives, the production risk and the technical efficiency. The study also attempts to determine the socio-economic and farm characteristics that influence technical efficiency of maize production in the study area. The findings of the study showed the existence of both production risk and technical inefficiency in maize production process. Input variables (amounts per hectare such as fertilizer and labor positively influence maize output. The findings also show that farms in the study area exhibit decreasing returns to scale. Fertilizer and ox plough days reduce output risk while labor and improved seed increase output risk. The mean technical efficiency for maize farms is 48 percent. This study concludes that production risk and technical inefficiency prevents the maize farmers from realizing their frontier output. The best factors that improve the efficiency of the maize farmers in the study area include: frequency of extension contact, access to credit and use of intercropping. It was also realized that altitude and terracing in maize farms had influence on farmer efficiency.

  20. Susceptibility and aversion of Spodoptera frugiperda (Lepidoptera: Noctuidae) to Cry1F Bt maize and considerations for insect resistance management.

    Science.gov (United States)

    Binning, Rachel R; Coats, Joel; Kong, Xiaoxiao; Hellmich, Richard L

    2014-02-01

    Bacillus thuringiensis (Bt) maize was developed primarily for North American pests such as European corn borer (Ostrinia nubilalis (Hübner)). However, most Bt maize products are also cultivated outside of North America, where the primary pests may be different and may have lower susceptibility to Bt toxins. Fall armyworm (Spodoptera frugiperda JE Smith) is an important pest and primary target of Bt maize in Central and South America. S. frugiperda susceptibility to Cry1F (expressed in event TC1507) is an example of a pest-by-toxin interaction that does not meet the high-dose definition. In this study, the behavioral and toxic response of S. frugiperda to Cry1F maize was investigated by measuring the percentage of time naive third instars spent feeding during a 3-min exposure. S. frugiperda also were exposed as third instars to Cry1F maize for 14 d to measure weight gain and survival. S. frugiperda demonstrated an initial, postingestive aversive response to Cry1F maize, and few larvae survived the 14 d exposure. The role of susceptibility and avoidance are discussed in the context of global IRM refuge strategy development for Bt products.

  1. A selfish gene governing pollen-pistil compatibility confers reproductive isolation between maize relatives.

    Science.gov (United States)

    Kermicle, Jerry L

    2006-01-01

    Some populations of maize's closest relatives, the annual teosintes of Mexico, are unreceptive to maize pollen. When present in the pistil (silk and ovary) a number of maize genes discriminate against or exclude pollen not carrying the same allele. An analogous gene Tcb1-s was found in some teosinte populations but not in sympatric or parapatric maize. It was polymorphic among populations of teosinte growing wild, but regularly present in populations growing in intimate association with maize as a weed. Introduction of Tcb1-s into maize substantially to fully restored compatibility with Tcb1-s carrying teosintes. Although Tcb1-s pollen can fertilize tcb1 tcb1 maize, it is at a competitive disadvantage relative to tcb1 pollen. Hence, the influence of Tcb1-s on crossability is bidirectional. In the absence of maize, Tcb1-s can increase in teosinte populations without improving their fitness. In the presence of maize, Tcb1-s appears to have been co-opted to provide reproductive isolation for adaptation to a cultivated habitat.

  2. Registration of Mp718 and Mp719 germplasm lines of maize

    Science.gov (United States)

    Maize (Zea mays L.) germplasm lines Mp718 (Reg. No. GP-xxxx, PI 662045) and Mp719 (Reg. No. GP-xxxx, PI 662046) were developed and released by USDA-ARS in cooperation with the Mississippi Agricultural and Forestry Experiment Station, Mississippi State, Mississippi, as sources of resistance to aflat...

  3. Impact of Glycolate Anion on Aqueous Corrosion in DWPF and Downstream Facilities

    Energy Technology Data Exchange (ETDEWEB)

    Mickalonis, J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2017-07-12

    Glycolic acid is being evaluated as an alternate reductant in the preparation of high level waste for the Defense Waste Processing Facility (DWPF) at the Savannah River Site (SRS). During processing, the glycolic acid may not be completely consumed with small quantities of the glycolate anion being carried forward to other high level waste (HLW) facilities. The SRS liquid waste contractor requested an assessment of the impact of the glycolate anion on the corrosion of the materials of construction (MoC) throughout the waste processing system since this impact had not been previously evaluated. A literature review revealed that corrosion data were not available for the MoCs in glycolic-bearing solutions applicable to SRS systems. Data on the material compatibility with only glycolic acid or its derivative products were identified; however, data were limited for solutions containing glycolic acid or the glycolate anion. For the proprietary coating systems applied to the DWPF concrete, glycolic acid was deemed compatible since the coatings were resistant to more aggressive chemistries than glycolic acid. Additionally similar coating resins showed acceptable resistance to glycolic acid.

  4. Impact of Glycolate Anion on Aqueous Corrosion in DWPF and Downstream Facilities

    Energy Technology Data Exchange (ETDEWEB)

    Mickalonis, J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2017-11-20

    Glycolic acid is being evaluated as an alternate reductant in the preparation of high level waste for the Defense Waste Processing Facility (DWPF) at the Savannah River Site (SRS). During processing, the glycolic acid may not be completely consumed with small quantities of the glycolate anion being carried forward to other high level waste (HLW) facilities. The SRS liquid waste contractor requested an assessment of the impact of the glycolate anion on the corrosion of the materials of construction (MoC) throughout the waste processing system since this impact had not been previously evaluated. A literature review revealed that corrosion data were not available for the MoCs in glycolic-bearing solutions applicable to SRS systems. Data on the material compatibility with only glycolic acid or its derivative products were identified; however, data were limited for solutions containing glycolic acid or the glycolate anion. For the proprietary coating systems applied to the DWPF concrete, glycolic acid was deemed compatible since the coatings were resistant to more aggressive chemistries than glycolic acid. Additionally, similar coating resins showed acceptable resistance to glycolic acid.

  5. Changes in Phenolic Acid Content in Maize during Food Product Processing.

    Science.gov (United States)

    Butts-Wilmsmeyer, Carrie J; Mumm, Rita H; Rausch, Kent D; Kandhola, Gurshagan; Yana, Nicole A; Happ, Mary M; Ostezan, Alexandra; Wasmund, Matthew; Bohn, Martin O

    2018-04-04

    The notion that many nutrients and beneficial phytochemicals in maize are lost due to food product processing is common, but this has not been studied in detail for the phenolic acids. Information regarding changes in phenolic acid content throughout processing is highly valuable because some phenolic acids are chemopreventive agents of aging-related diseases. It is unknown when and why these changes in phenolic acid content might occur during processing, whether some maize genotypes might be more resistant to processing induced changes in phenolic acid content than other genotypes, or if processing affects the bioavailability of phenolic acids in maize-based food products. For this study, a laboratory-scale processing protocol was developed and used to process whole maize kernels into toasted cornflakes. High-throughput microscale wet-lab analyses were applied to determine the concentrations of soluble and insoluble-bound phenolic acids in samples of grain, three intermediate processing stages, and toasted cornflakes obtained from 12 ex-PVP maize inbreds and seven hybrids. In the grain, insoluble-bound ferulic acid was the most common phenolic acid, followed by insoluble-bound p-coumaric acid and soluble cinnamic acid, a precursor to the phenolic acids. Notably, the ferulic acid content was approximately 1950 μg/g, more than ten-times the concentration of many fruits and vegetables. Processing reduced the content of the phenolic acids regardless of the genotype. Most changes occurred during dry milling due to the removal of the bran. The concentration of bioavailable soluble ferulic and p-coumaric acid increased negligibly due to thermal stresses. Therefore, the current dry milling based processing techniques used to manufacture many maize-based foods, including breakfast cereals, are not conducive for increasing the content of bioavailable phenolics in processed maize food products. This suggests that while maize is an excellent source of phenolics, alternative

  6. Characterization of rhizobacteria associated to maize crop in IAA, siderophores and salicylic acid metabolite production

    Directory of Open Access Journals (Sweden)

    Annia Hernández

    2004-01-01

    Full Text Available It has been demonstrated that rhizobacteria are able to produce metabolites having agricultural interest, including salicylic acid, the siderophores and phytohormones. Indol acetic acid (IAA is the most well-known and studied auxin, playing a governing role in culture growth. The object of this work was to characterise rhizobacteria associated with the maize crop in terms of producing IAA, siderophores and salicylic acid metabolites. Burkholderia cepacia and Pseudomonas fluorescens strains previously isolated from maize Francisco variety rhizosphere were used. Colorimetric and chromatographic techniques for detecting these metabolites were studied; multi-variable analysis of hierarchic conglomerate and complete ligament were used for selecting the best strains for producing metabolites of interest. These results demonstrated that all rhizobacteria strains studied produced IAA, siderophores and salicylic acid metabolites. Burkholderia cepacia MBf21, MBp1, MBp2, MBf22, MBp3, MBf20, MBf 15 and Pseudomonas fluorescens MPp4strains have presented the greatest production of these metabolites, showing that these strains could be used in promoting vegetal growth in economically important cultures. Key words: Pseudomonas fluorescens, Burkholderia cepacia, IAA, siderophore, salicylic acid.

  7. Screening of promising maize genotypes against maize weevil (Sitophilus zeamais Motschulky) in storage condition

    OpenAIRE

    Ram B Paneru; Resham B Thapa

    2017-01-01

    The maize weevil (Sitophilus zeamais Motschulsky) is a serious pest of economic importance in stored grains. It causes major damage to stored maize grain thereby reducing its weight, quality and germination. An experiment was conducted in randomized complete block design (RCBD) with 3 replications to screen 32 maize genotypes against maize weevil in no-choice and free-choice conditions at Entomology Division, Khumaltar, Lalitpur (Room temperature: Maximum 24-32°C and Minimum 18-27°C). The fin...

  8. Exploring karyotype diversity of Argentinian Guaraní maize landraces: Relationship among South American maize.

    Directory of Open Access Journals (Sweden)

    María Florencia Realini

    Full Text Available In Argentina there are two different centers of maize diversity, the Northeastern (NEA and the Northwestern (NWA regions of the country. In NEA, morphological studies identified 15 landraces cultivated by the Guaraní communities in Misiones Province. In the present study we analyzed the karyotype diversity of 20 populations of Guaraní maize landraces through classical and molecular cytogenetic analyses. Our results demonstrate significant intra and inter-populational variation in the percentage, number, size, chromosome position and frequencies of the heterochromatic blocks, which are called knobs. Knob sequence analysis (180-bp and TR-1 did not show significant differences among Guaraní populations. B chromosomes were not detected, and abnormal 10 (AB10 chromosomes were found with low frequency (0.1≥f ≤0.40 in six populations. Our results allowed karyotypic characterization of each analyzed population, defining for the first time the chromosomal constitution of maize germplasm from NEA. The multivariate analysis (PCoA and UPGMA of karyotype parameters allowed the distinction between two populations groups: the Popcorn and the Floury maize populations. These results are in agreement with previously published microsatellite and morphological/phenological studies. Finally, we compared our karyotype results with those previously reported for NWA and Central Region of South America maize. Our data suggest that there are important differences between maize from NEA and NWA at the karyotype level, supporting the hypothesis that there are two pathways of input of South America maize. Our results also confirm the existence of two centers of diversification of Argentinian native maize, NWA and NEA. This work contributes new knowledge about maize diversity, which is relevant for future plans to improve commercial maize, and for conservation of agrobiodiversity.

  9. Omethoate treatment mitigates high salt stress inhibited maize seed germination.

    Science.gov (United States)

    Yang, Kejun; Zhang, Yifei; Zhu, Lianhua; Li, Zuotong; Deng, Benliang

    2018-01-01

    Omethoate (OM) is a highly toxic organophophate insecticide, which is resistant to biodegradation in the environment and is widely used for pest control in agriculture. The effect of OM on maize seed germination was evaluated under salt stress. Salt (800mM) greatly reduced germination of maize seed and this could be reversed by OM. Additionally, H 2 O 2 treatment further improved the effect of OM on seed germination. Higher H 2 O 2 content was measured in OM treated seed compared to those with salt stress alone. Dimethylthiourea (DTMU), a specific scavenger of reactive oxygen species (ROS), inhibited the effect of OM on seed germination, as did IMZ (imidazole), an inhibitor of NADPH oxidase. Abscisic acid (ABA) inhibited the effect of OM on seed germination, whereas fluridone, a specific inhibitor of ABA biosynthesis, enhanced the effect of OM. Taken together, these findings suggest a role of ROS and ABA in the promotion of maize seed germination by OM under salt stress. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Occurrence of toxigenic fungi in maize and maize-gluten meal from Pakistan

    Directory of Open Access Journals (Sweden)

    Muhammad Kashif SALEEMI

    2012-05-01

    Full Text Available The present study was designed to isolate and identify toxigenic mycoflora of maize and maize-gluten meal. A total of 82 samples of maize and 8 samples of maize-gluten meal were collected from Faisalabad district of Pakistan over a period of two years. These samples were inoculated on different culture media. Fungal contamination of maize and maize-gluten was 56% and 75% of samples, respectively. Isolation frequencies of different genera isolated from maize were Aspergillus 33%; Penicillium 28%; Fusarium 10%; and Alternaria 1%. Isolation frequency among species was maximum for P. verrucosum, followed by A. niger aggregates, A. ochraceous, A. flavus, P. chrysogenum, A. parasiticus, A. carbonarius, Fusarium spp. and Alternaria spp. Relative density of Aspergillus isolates was maximum for A. niger aggregates and A. ochraceous (30% each followed by A. flavus (26%, A. parasiticus (11% and A. carbonarius (3%. Percentage of toxigenic fungi among Aspergillus isolates was 52%. Aflatoxigenic isolates of A. flavus and A. parasiticus were 43 and 67% and ochratoxigenic isolates of A. carbonarius, A. ochraceous and A. niger aggregates were 100, 63 and 38%, respectively. Aspergillus parasiticus produced higher concentrations of AFB1 (maximum 1374.23 ng g-1 than A. flavus (maximum 635.50 ng g-1. Ochratoxin A production potential of A. ochraceous ranged from 1.81 to 9523.1 ng g-1, while in A. niger aggregates it was 1.30 to 1758.6 ng g-1. Isolation frequencies of fungal genera from maize-gluten meal were Aspergillus (63% and Penicillium (50%. A. flavus was the most frequently isolated species. Percentage of toxigenic fungi among Aspergillus isolates was 40%. Aflatoxigenic isolates of A. flavus were 33% and ochratoxigenic isolates of A. ochraceous were 100%.

  11. Global maize production, utilization, and consumption.

    Science.gov (United States)

    Ranum, Peter; Peña-Rosas, Juan Pablo; Garcia-Casal, Maria Nieves

    2014-04-01

    Maize (Zea mays), also called corn, is believed to have originated in central Mexico 7000 years ago from a wild grass, and Native Americans transformed maize into a better source of food. Maize contains approximately 72% starch, 10% protein, and 4% fat, supplying an energy density of 365 Kcal/100 g and is grown throughout the world, with the United States, China, and Brazil being the top three maize-producing countries in the world, producing approximately 563 of the 717 million metric tons/year. Maize can be processed into a variety of food and industrial products, including starch, sweeteners, oil, beverages, glue, industrial alcohol, and fuel ethanol. In the last 10 years, the use of maize for fuel production significantly increased, accounting for approximately 40% of the maize production in the United States. As the ethanol industry absorbs a larger share of the maize crop, higher prices for maize will intensify demand competition and could affect maize prices for animal and human consumption. Low production costs, along with the high consumption of maize flour and cornmeal, especially where micronutrient deficiencies are common public health problems, make this food staple an ideal food vehicle for fortification. © 2014 New York Academy of Sciences. The World Health Organization retains copyright and all other rights in the manuscript of this article as submitted for publication.

  12. Breeding of speciality maize for industrial purposes

    OpenAIRE

    Pajić Zorica; Radosavljević Milica; Filipović Milomir; Todorović Goran; Srdić Jelena; Pavlov Milovan

    2010-01-01

    The breeding programme on speciality maize with specific traits was established at the Maize Research Institute, Zemun Polje, several decades ago. The initial material was collected, new methods applying to breeding of speciality maize, i.e. popping maize, sweet maize and white-seeded maize, were introduced. The aim was to enhance and improve variability of the initial material for breeding these three types of maize. Then, inbred lines of good combining abilities were developed and used as c...

  13. Aflatoxin levels in maize and maize products during the 2004 food ...

    African Journals Online (AJOL)

    Aflatoxin levels in maize and maize products during the 2004 food poisoning ... district were received at the National Public Health Laboratory Services (NPHLS). On analysis, they were found to be highly contaminated with aflatoxin B1.

  14. Maize production in mid hills of Nepal: from food to feed security

    Directory of Open Access Journals (Sweden)

    Krishna Prasad Timsina

    2016-12-01

    Full Text Available This study was undertaken in 2016 to analyze the production and utilization of maize in Nepal. Sixty maize growers from Kavre and Lamjung districts were selected using purposive, cluster and simple random sampling techniques. Similarly, six feed industries and five maize experts from Chitwan district were also interviewed. Study shows 56% of the total areas were used for maize production and 50% of the maize areas were covered by hybrid maize. There was no practice of contract maize production. The results revealed that 60%, 25% and 3% of the grain were used for animal feed, food and seed respectively in hill districts. Whereas the remaining amount of the maize (12% was sold to the different buyers. The proportion of maize feed supply to different animals in the study area was varying. Result shows that at least 1.5 million tons of maize is required only to the feed industries affiliated with national feed industry association in Nepal. Similarly, out of total maize used in feed production, 87% of the maize was imported from India each year by feed industries. Analysis shows negative correlation between scale of feed production and use of domestic maize due to unavailability of required quantity of maize in time. The major pre-condition of feed industries for maize buying was moisture content which must be equal or less than 14%. Very little or no inert materials and physical injury, free from fungal attack and bigger size were also the criteria for maize buying. However, some of the feed industries were also thinking about protein and amino acid contents. Result shows 13% and 8.5% increasing demand of poultry feed and animal feed, respectively over the last five year in Nepal. Most likely, maize is known as a means of food security in Nepal, however, in the context of changing utilization patterns at the farm level and also tremendous increasing demand of maize at the industry level suggest to give more focus on development and dissemination of

  15. Toxin distribution and sphingoid base imbalances in Fusarium verticillioides-infected and fumonisin B1-watered maize seedlings.

    Science.gov (United States)

    Arias, Silvina L; Mary, Verónica S; Otaiza, Santiago N; Wunderlin, Daniel A; Rubinstein, Héctor R; Theumer, Martín G

    2016-05-01

    Fusarium verticillioides is a major maize pathogen and there are susceptible and resistant cultivars to this fungal infection. Recent studies suggest that its main mycotoxin fumonisin B1 (FB1) may be involved in phytopathogenicity, but the underlying mechanisms are mostly still unknown. This work was aimed at assessing whether FB1 disseminates inside the plants, as well as identifying possible correlations between the maize resistant/susceptible phenotype and the unbalances of the FB1-structurally-related sphingoid base sphinganine (Sa) and phytosphingosine (Pso) due to toxin accumulation. Resistant (RH) and susceptible hybrid (SH) maize seedlings grown from seeds inoculated with a FB1-producer F. verticillioides and from uninoculated ones irrigated with FB1 (20 ppm), were harvested at 7, 14 and 21 days after planting (dap), and the FB1, Sa and Pso levels were quantified in roots and aerial parts. The toxin was detected in roots and aerial parts for inoculated and FB1-irrigated plants of both hybrids. However, FB1 levels were overall higher in SH seedlings regardless of the treatment (infection or watering). Sa levels increased substantially in RH lines, peaking at 54-fold in infected roots at 14 dap. In contrast, the main change observed in SH seedlings was an increase of Pso in infected roots at 7 dap. Here, it was found that FB1 disseminates inside seedlings in the absence of FB1-producer fungal infections, perhaps indicating this might condition the fungus-plant interaction before the first contact. Furthermore, the results strongly suggest the existence of at least two ceramide synthase isoforms in maize with different substrate specificities, whose differential expression after FB1 exposure could be closely related to the susceptibility/resistance to F. verticillioides. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Species of Cercospora associated with grey leaf spot of maize.

    Science.gov (United States)

    Crous, Pedro W; Groenewald, Johannes Z; Groenewald, Marizeth; Caldwell, Pat; Braun, Uwe; Harrington, Thomas C

    2006-01-01

    Grey leaf spot is a serious yield-reducing disease of maize (Zea mays) in many parts of the world where this crop is cultivated. The causal organism associated with the disease is Cercospora zeae-maydis. Two potential sibling species have been recognized as Groups I and II. The DNA sequences for the internal transcribed spacers (ITS1 & ITS2), the 5.8S rRNA gene, elongation factor 1-alpha, histone H3, actin and calmodulin gene regions suggest that Groups I and II are two distinct species. Furthermore, Cercospora zeae-maydis (Group I) can be distinguished from C. zeina sp. nov. (Group II) by its faster growth rate on artificial media, the ability to produce cercosporin, longer conidiophores, and broadly fusiform conidia. A PCR-based test that distinguishes the two species was developed using species-specific primers designed from the histone H3 gene.

  17. Recombination in diverse maize is stable, predictable, and associated with genetic load.

    Science.gov (United States)

    Rodgers-Melnick, Eli; Bradbury, Peter J; Elshire, Robert J; Glaubitz, Jeffrey C; Acharya, Charlotte B; Mitchell, Sharon E; Li, Chunhui; Li, Yongxiang; Buckler, Edward S

    2015-03-24

    Among the fundamental evolutionary forces, recombination arguably has the largest impact on the practical work of plant breeders. Varying over 1,000-fold across the maize genome, the local meiotic recombination rate limits the resolving power of quantitative trait mapping and the precision of favorable allele introgression. The consequences of low recombination also theoretically extend to the species-wide scale by decreasing the power of selection relative to genetic drift, and thereby hindering the purging of deleterious mutations. In this study, we used genotyping-by-sequencing (GBS) to identify 136,000 recombination breakpoints at high resolution within US and Chinese maize nested association mapping populations. We find that the pattern of cross-overs is highly predictable on the broad scale, following the distribution of gene density and CpG methylation. Several large inversions also suppress recombination in distinct regions of several families. We also identify recombination hotspots ranging in size from 1 kb to 30 kb. We find these hotspots to be historically stable and, compared with similar regions with low recombination, to have strongly differentiated patterns of DNA methylation and GC content. We also provide evidence for the historical action of GC-biased gene conversion in recombination hotspots. Finally, using genomic evolutionary rate profiling (GERP) to identify putative deleterious polymorphisms, we find evidence for reduced genetic load in hotspot regions, a phenomenon that may have considerable practical importance for breeding programs worldwide.

  18. Integrating varietal resistance with Xylopia aethiopica (Dunal) A ...

    African Journals Online (AJOL)

    The different rates of X. aethiopica extract significantly interacted with maize varietal resistance and reduced fecundity of S. zeamais and maize seed weight loss due to insect's feeding. Treatment of seeds with extract at 1.0 ml/20 g seed caused significant (above 50%) mortality at 24 h post treatment in all varieties whereas ...

  19. From many, one: genetic control of prolificacy during maize domestication.

    Directory of Open Access Journals (Sweden)

    David M Wills

    2013-06-01

    Full Text Available A reduction in number and an increase in size of inflorescences is a common aspect of plant domestication. When maize was domesticated from teosinte, the number and arrangement of ears changed dramatically. Teosinte has long lateral branches that bear multiple small ears at their nodes and tassels at their tips. Maize has much shorter lateral branches that are tipped by a single large ear with no additional ears at the branch nodes. To investigate the genetic basis of this difference in prolificacy (the number of ears on a plant, we performed a genome-wide QTL scan. A large effect QTL for prolificacy (prol1.1 was detected on the short arm of chromosome 1 in a location that has previously been shown to influence multiple domestication traits. We fine-mapped prol1.1 to a 2.7 kb "causative region" upstream of the grassy tillers1 (gt1 gene, which encodes a homeodomain leucine zipper transcription factor. Tissue in situ hybridizations reveal that the maize allele of prol1.1 is associated with up-regulation of gt1 expression in the nodal plexus. Given that maize does not initiate secondary ear buds, the expression of gt1 in the nodal plexus in maize may suppress their initiation. Population genetic analyses indicate positive selection on the maize allele of prol1.1, causing a partial sweep that fixed the maize allele throughout most of domesticated maize. This work shows how a subtle cis-regulatory change in tissue specific gene expression altered plant architecture in a way that improved the harvestability of maize.

  20. Comparative analysis of the genetic basis of Cry1F resistance in two strains of Spodoptera frugiperda originated from Puerto Rico and Florida.

    Science.gov (United States)

    Camargo, Ana M; Castañera, Pedro; Farinós, Gema P; Huang, Fangneng

    2017-06-01

    The fall armyworm, Spodoptera frugiperda (J.E. Smith), is a major target pest of Bacillus thuringiensis (Bt) maize and cotton in America. Since the commercialization of Cry1F maize (event TC1507) in 2003, resistance to Cry1F maize in field populations of S. frugiperda has occurred in Puerto Rico, Brazil and the southeast region of the United States. In this paper, we conducted a comparative analysis of the inheritance of two Cry1F-resistant colonies of S. frugiperda originated from Puerto Rico (PR) and Florida (FL), respectively. The objective of the analysis was to determine if the genetic basis of the resistance was similar in the two different originated colonies. To accomplish the objective, besides PR, FL, and a known Cry1F-susceptible colony, 14 additional colonies were developed by reciprocal crosses among the three parents, F 1 by F 1 crosses, backcrosses, and intercolony-crosses between PR and FL. Larval mortalities of the 17 colonies were assayed on both Cry1F maize leaf tissue and Cry1F-treated diet at the concentrations of 3.16, 10.00, and 31.60µg/g. Resistance to Cry1F in both PR and FL was autosomal and recessive or incompletely recessive. Segregations in F 2 and backcrossed generations associated with FL fitted the Mendelian monogenic model well, while with PR the segregations did not follow the single gene model in some bioassays. Further analyses with the intercolony complementation tests showed a similar level of resistance in the F 1 progeny as their parents FL and PR. Together with the data, it was likely that a single (or a few tightly-linked) gene was involved in FL; PR shared the same locus of the major resistance gene as FL, but the resistance in PR might also be associated with additional minor factors. Information generated from this study should be useful in understanding the origin of Cry1F resistance in the U.S. mainland and developing effective strategies for Bt resistance management in S. frugiperda. Copyright © 2017 Elsevier Inc

  1. Energy productivity and efficiency of maize accounting for the choice of growing season and environmental factors: An empirical analysis from Bangladesh

    International Nuclear Information System (INIS)

    Rahman, Sanzidur; Rahman, Md. Sayedur

    2013-01-01

    The paper evaluates sustainability of maize cultivation in Bangladesh in terms of energy use while taking into account factors affecting choice of the growing season and farmers' production environment using a sample selection framework applied to stochastic frontier models. Results reveal that the probability of growing winter maize is influenced positively by gross return, irrigation, subsistence pressure, soil suitability and temperature variability whereas extension contact influences choice negatively. Significant differences exist between winter and summer maize regarding yield, specific energy, net energy balance, energy use efficiency and technical energy efficiency although both systems are highly sustainable and efficient. The energy output from winter maize is 199,585 MJ/ha which is 53.9% higher than the summer maize output of 129,701 MJ/ha. Also, energy input use of winter maize is 110.6% higher than the summer maize. Energy inputs from mechanical power, seeds, fertilizers and organic manures significantly increase energy productivity of winter maize whereas only mechanical power influences summer maize productivity. However, temperature variation and rainfall significantly reduce energy productivity of summer maize. Policy implications include investments in soil conservation and irrigation, development of weather resistant varieties and raising maize price will boost maize cultivation in Bangladesh, a highly sustainable production technology. -- Highlights: ► Maize energy productivity is evaluated subject to season and environmental factors. ► Maize farming for both seasons is highly sustainable in terms of energy use. ► Socio-economic and environmental factors influence choice of growing winter maize. ► Mechanical power, rainfall and temperature influence summer maize productivity. ► Maize farmers of both seasons are highly technically efficient.

  2. Diallel crosses among maize lines with emphasis on resistance to foliar diseases

    Directory of Open Access Journals (Sweden)

    Maria Elisa Ayres Guidetti Zagatto Paterniani

    2000-06-01

    Full Text Available Ten elite maize (Zea mays L. lines were crossed in a complete diallel scheme and the single-cross hybrids obtained were assessed at four experimental stations of the Agronomic Institute of Campinas, in São Paulo State, Brazil. The experiments were set up in a randomized complete block design with three replications, including four commercial checks. The experimental plots consisted of two 5-m rows spaced at 0.9 m, with a total of 50 plants. The traits assessed included: days to mid-tassel pollen shed (DPS, plant height (PH, ear height (EH, grain yield, corrected for a 50-plant stand and 14% moisture (GY corr., and resistance to Phaeosphaeria maydis and Puccinia polysora. General and specific combining ability effects (GCA and SCA were determined. There was extensive genetic variability among hybrids with the best hybrids (HS 04 x 10 and HS 10 x 11 not differing from the commercial checks. The lines with the greatest potential for hybrid synthesis included: L 10, L 11 and L 13, because they had higher GCA for yield, moderate resistance to P. maydis and reduced EH. The greatest contribution to reduction of the Phaeosphaeria stain was obtained with L 5. The magnitude of the GCA relative to the total variation indicated that additive effects predominated for resistance to P. maydis and P. polysora. Significant SCA (P Cruzaram-se dez linhagens-elite de milho em esquema dialélico completo e os híbridos simples obtidos foram avaliados em quatro Núcleos Experimentais do Instituto Agronômico de Campinas, SP, Brasil. Os ensaios foram instalados sob delineamento de blocos casualizados com três repetições, incluindo quatro testemunhas comerciais. As parcelas consistiram em duas linhas de 5 m espaçadas por 0,90 m, contendo 50 plantas. Avaliaram-se os caracteres: dias para o florescimento masculino (DPS, altura da planta (PH e da espiga (EH, produtividade de grãos corrigida para estande ideal de 50 plantas e 14% de umidade (GY corr. e resistência a

  3. Adapting to warmer climate through prolonged maize grain filling period in the US Midwest

    Science.gov (United States)

    Zhu, P.; Zhuang, Q.; Jin, Z.

    2017-12-01

    Climate warming is expected to negatively impact the US food productivity. How to adapt to the future warmer environment and meet the rising food requirement becomes unprecedented urgent. Continuous satellite observational data provides an opportunity to examine the historic responses of crop plants to climate variation. Here 16 years crop growing phases information across US Midwest is generated based on satellite observations. We found a prolonged grain-filling period during 2000-2015, which could partly explain the increasing trend in Midwest maize yield. This longer grain-filling period might be resulted from the adoption of longer maturity group varieties or more resistant varieties to temperature variation. Other management practice changes like advance in planting date could be also an effective way of adapting future warmer climate through lowering the possibility of exposure to heat and drought stresses. If the progress in breeding technology enables the maize grain-filling period to prolong with the current rate, the maize grain filling length could be longer and maize yield in Midwest could adapt to future climate despite of the warming.

  4. Functional diversity of staphylinid beetles (Coleoptera: Staphylinidae) in maize fields: testing the possible effect of genetically modified, insect resistant maize

    Czech Academy of Sciences Publication Activity Database

    Svobodová, Zdeňka; Skoková Habuštová, Oxana; Boháč, J.; Sehnal, František

    2016-01-01

    Roč. 106, č. 4 (2016), s. 432-445 ISSN 0007-4853 R&D Projects: GA MZe QH91093 Grant - others:GA JU(CZ) 038/2014/P; project MOBILITY(CZ) 7AMB14SK096 Program:7A Institutional support: RVO:60077344 Keywords : GM crops * Bt maize * Cry3Bb1 Subject RIV: GF - Plant Pathology, Vermin, Weed, Plant Protection Impact factor: 1.758, year: 2016

  5. Evaluation of stem borer resistance management strategies for Bt ...

    African Journals Online (AJOL)

    Stem borers are the major insect pests of maize in Kenya. The use of Bacillus thuringiensis (Bt) technology is an effective way of controlling lepidopteran pests. However, the likelihood of development of resistance to the Bt toxins by the target stem borer species is a concern. Forages, sorghum and maize varieties were ...

  6. Screening of promising maize genotypes against maize weevil (Sitophilus zeamais Motschulky in storage condition

    Directory of Open Access Journals (Sweden)

    Ram B Paneru

    2017-12-01

    Full Text Available The maize weevil (Sitophilus zeamais Motschulsky is a serious pest of economic importance in stored grains. It causes major damage to stored maize grain thereby reducing its weight, quality and germination. An experiment was conducted in randomized complete block design (RCBD with 3 replications to screen 32 maize genotypes against maize weevil in no-choice and free-choice conditions at Entomology Division, Khumaltar, Lalitpur (Room temperature: Maximum 24-32°C and Minimum 18-27°C. The findings showed that the maize genotypes had different response to maize weevil damage ranging from susceptible to tolerance. The genotypes Manakamana-3, Lumle White POP Corn and Ganesh-2 showed their tolerance to S. zeamais as evidenced by lower number of weevil emerged/attracted, lower amount of grain debris release and lower proportion of bored grains, while the genotype ZM-627 was the most susceptible to weevil damage in both tests. The other remaining genotypes were intermediate types. This information is useful to improve grain protection in storage and varietal improvement/release program.

  7. Anion retention in soil: Possible application to reduce migration of buried technetium and iodine

    International Nuclear Information System (INIS)

    Gu, B.; Schulz, R.K.

    1991-10-01

    This report summarizes a literature review of our present knowledge of the anion exchange properties of a number of soils and minerals, which may potentially be used as anion exchangers to retard migration of such anions as iodide (I - ), iodate (IO 3 - ) and pertechnetate (TcO 4 - ) away from disposal site. The amorphous clays allophane and imogolite, are found to be among the most important soil components capable of developing appreciable amounts of positive charge for anion exchange even at about neutral pH. Decreases in the SiO 2 /Al 2 O 3 ratio and soil pH result in an increase in soil AEC. Allophane and imogolite rich soils have an AEC ranging from 1 to 18 meq/100g at pH about 6. Highly weathered soils dominated by Fe and Al oxides and kaolinite may develop a significant amount of AEC as soil pH falls. The retention of iodine (I) and technetium (T c ), by soils is associated with both soil organic matter, and Fe and Al oxides, whereas sorption on layer silicate minerals in negligible. Fe and Al oxides become more important in the retention of anionic I - , IO 3 - , and TcO 4 - as pH falls, since more positive charge is developed on the oxide surfaces. Although few studies, if any, have been conducted on I and T c sorption by soil allophane and imogolite, it is estimated that a surface plough soil (2 million pounds soil per acre) with 5 meq/100g AEC, as is commonly found in andisols, shall retain approximately 5900 kg I and 4500 kg T c . It is conceivable that an anion exchanger such as an andisol could be used to modify the near field environment of a radioactive waste disposal facility. This whole disposal system would then offer similar migration resistance to anions as is normally afforded to cations by usual and normal soils. 93 refs., 10 figs., 7 tabs

  8. Anion retention in soil: Possible application to reduce migration of buried technetium and iodine

    Energy Technology Data Exchange (ETDEWEB)

    Gu, B.; Schulz, R.K. (California Univ., Berkeley, CA (United States). Dept. of Soil Science)

    1991-10-01

    This report summarizes a literature review of our present knowledge of the anion exchange properties of a number of soils and minerals, which may potentially be used as anion exchangers to retard migration of such anions as iodide (I{sup {minus}}), iodate (IO{sub 3}{sup {minus}}) and pertechnetate (TcO{sub 4}{sup {minus}}) away from disposal site. The amorphous clays allophane and imogolite, are found to be among the most important soil components capable of developing appreciable amounts of positive charge for anion exchange even at about neutral pH. Decreases in the SiO{sub 2}/Al{sub 2}O{sub 3} ratio and soil pH result in an increase in soil AEC. Allophane and imogolite rich soils have an AEC ranging from 1 to 18 meq/100g at pH about 6. Highly weathered soils dominated by Fe and Al oxides and kaolinite may develop a significant amount of AEC as soil pH falls. The retention of iodine (I) and technetium ({Tc}), by soils is associated with both soil organic matter, and Fe and Al oxides, whereas sorption on layer silicate minerals in negligible. Fe and Al oxides become more important in the retention of anionic I{sup {minus}}, IO{sub 3}{sup {minus}}, and TcO{sub 4}{sup {minus}} as pH falls, since more positive charge is developed on the oxide surfaces. Although few studies, if any, have been conducted on I and {Tc} sorption by soil allophane and imogolite, it is estimated that a surface plough soil (2 million pounds soil per acre) with 5 meq/100g AEC, as is commonly found in andisols, shall retain approximately 5900 kg I and 4500 kg {Tc}. It is conceivable that an anion exchanger such as an andisol could be used to modify the near field environment of a radioactive waste disposal facility. This whole disposal system would then offer similar migration resistance to anions as is normally afforded to cations by usual and normal soils. 93 refs., 10 figs., 7 tabs.

  9. The Thermodynamics of Anion Complexation to Nonpolar Pockets.

    Science.gov (United States)

    Sullivan, Matthew R; Yao, Wei; Tang, Du; Ashbaugh, Henry S; Gibb, Bruce C

    2018-02-08

    The interactions between nonpolar surfaces and polarizable anions lie in a gray area between the hydrophobic and Hofmeister effects. To assess the affinity of these interactions, NMR and ITC were used to probe the thermodynamics of eight anions binding to four different hosts whose pockets each consist primarily of hydrocarbon. Two classes of host were examined: cavitands and cyclodextrins. For all hosts, anion affinity was found to follow the Hofmeister series, with associations ranging from 1.6-5.7 kcal mol -1 . Despite the fact that cavitand hosts 1 and 2 possess intrinsic negative electrostatic fields, it was determined that these more enveloping hosts generally bound anions more strongly. The observation that the four hosts each possess specific anion affinities that cannot be readily explained by their structures, points to the importance of counter cations and the solvation of the "empty" hosts, free guests, and host-guest complexes, in defining the affinity.

  10. Analysis of recombination QTLs, segregation distortion, and epistasis for fitness in maize multiple populations using ultra-high-density markers

    Science.gov (United States)

    Understanding the maize genomic features would be useful for the study of genetic diversity and evolution and for maize breeding. Here, we used two maize nested association mapping (NAM) populations separately derived in China (CN-NAM) and the US (US-NAM) to explore the maize genomic features. The t...

  11. Complete disintegration of the microtubular cytoskeleton precedes its auxin-mediated reconstruction in postmitotic maize root cells

    Science.gov (United States)

    Baluska, F.; Barlow, P. W.; Volkmann, D.

    1996-01-01

    The inhibitory action of 0.1 microM auxin (IAA) on maize root growth was closely associated with a rapid and complete disintegration of the microtubular (MT) cytoskeleton, as visualized by indirect immunofluorescence of tubulin, throughout the growth region. After 30 min of this treatment, only fluorescent spots were present in root cells, accumulating either around nuclei or along cell walls. Six h later, in addition to some background fluorescence, dense but partially oriented oblique or longitudinal arrays of cortical MTs (CMTs) were found in most growing cells of the root apex. After 24 h of treatment, maize roots had adapted to the auxin, as inferred from the slowly recovering elongation rate and from the reassembly of a dense and well-ordered MT cytoskeleton which showed only slight deviations from that of the control root cells. Taxol pretreatment (100 microM, 24 h) prevented not only the rapid auxin-mediated disintegration of the MT cytoskeleton but also a reorientation of the CMT arrays, from transversal to longitudinal. The only tissue to show MTs in their cells throughout the auxin treatment was the epidermis. Significant resistance of transverse CMT arrays in these cells towards auxin was confirmed using a higher auxin concentration (100 microM, 24 h). The latter auxin dose also revealed inter-tissue-specific responses to auxin: outer cortical cell files reoriented their CMTs from the transversal to longitudinal orientation, whereas inner cortical cell files lost their MTs. This high auxin-mediated response, associated with the swelling of root apices, was abolished with the pretreatment of maize root with taxol.

  12. Consumer preferences for maize products in urban Kenya.

    Science.gov (United States)

    De Groote, Hugo; Kimenju, Simon Chege

    2012-06-01

    New maize varieties have been biofortified with provitamin A, mainly a-carotene, which renders the grain yellow or orange. Unfortunately, many African consumers prefer white maize. The maize consumption patterns in Africa are, however, not known. To determine which maize products African consumers prefer to purchase and which maize preparations they prefer to eat. A survey of 600 consumers was conducted in Nairobi, Kenya, at three types of maize outlets: posho mills (small hammer mills), kiosks, and supermarkets. Clients of posho mills had lower incomes and less education than those of kiosks and supermarkets. The preferred maize product of the posho-mill clients was artisanal maize meal; the preferred product of the others was industrial maize meal. Maize is the preferred staple for lunch and dinner, eaten as a stiff porridge (ugali), followed by boiled maize and beans (githeri), regardless of socioeconomic background. For breakfast, only half the consumers prefer maize, mostly as a soft porridge (uji). This proportion is higher in low-income groups. Consumers show a strong preference for white maize over yellow, mostly for its organoleptic characteristics, and show less interest in biofortified maize. Maize is the major food staple in Nairobi, mostly eaten in a few distinct preparations. For biofortified yellow maize to be accepted, a strong public awareness campaign to inform consumers is needed, based on a sensory evaluation and the mass media, in particular on radio in the local language.

  13. Maize variety and method of production

    Science.gov (United States)

    Pauly, Markus; Hake, Sarah; Kraemer, Florian J

    2014-05-27

    The disclosure relates to a maize plant, seed, variety, and hybrid. More specifically, the disclosure relates to a maize plant containing a Cal-1 allele, whose expression results in increased cell wall-derived glucan content in the maize plant. The disclosure also relates to crossing inbreds, varieties, and hybrids containing the Cal-1 allele to produce novel types and varieties of maize plants.

  14. Fitness costs of Cry1F resistance in two populations of fall armyworm, Spodoptera frugiperda (J.E. Smith), collected from Puerto Rico and Florida.

    Science.gov (United States)

    Dangal, Vikash; Huang, Fangneng

    2015-05-01

    The development of resistance in target pest populations is a threat to the sustainability of transgenic crops expressing Bacillus thuringiensis (Bt) proteins. Fall armyworm, Spodoptera frugiperda (J.E. Smith), is a major target pest of Bt maize in North and South America. This insect is the first target pest that has developed field resistance to Bt maize at multiple locations in these regions. The objective of this study was to assess the fitness costs associated with the Cry1F resistance in two populations of S. frugiperda collected from Puerto Rico (RR-PR) and Florida (RR-FL). In the study, fitness costs were evaluated by comparing survival, growth, and developmental time of seven populations of S. frugiperda on (1) non-Bt meridic diet and (2) non-Bt maize leaf tissue and non-Bt diet. The seven populations were RR-PR, RR-FL, a Bt-susceptible strain (Bt-SS), and four F1 populations developed from reciprocal crosses between Bt-SS and the two resistant populations. Biological parameters measured were neonate-to-adult survivorship, neonate-to-adult developmental time, 10day larval weight on non-Bt maize leaf tissue, pupal weight, and sex ratios. Results of the study show that the Cry1F resistance in both RR-PR and RR-FL was associated with considerable fitness costs, especially for the Florida population. Compared to the Bt-susceptible population, RR-PR showed an average of 61.1% reduction in larval weight, 20.4% less in neonate-to-adult survivorship, and 3.7days delay in neonate-to-adult developmental time. These fitness costs for RR-FL were 66.9%, 31.7% and 4.4days, respectively. The fitness costs of RR-PR and RR-FL appeared to be non-recessive. The results indicate that a diversified genetic basis may exist for the Cry1F resistance in S. frugiperda. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. Cloning and expression of a sorghum gene with homology to maize vp1. Its potential involvement in pre-harvest sprouting resistance.

    Science.gov (United States)

    Carrari, F; Perez-Flore, L; Lijavetzky, D; Enciso, S; Sanchez, R; Benech-Arnold, R; Iusem, N

    2001-04-01

    Pre-harvest sprouting (PHS) in sorghum is related to the lack of a normal dormancy level during seed development and maturation. Based on previous evidence that seed dormancy in maize is controlled by the vp1 gene, we used a PCR-based approach to isolate two Sorghum bicolor genomic and cDNA clones from two genotypes exhibiting different PHS behaviour and sensitivity to abscisic acid (ABA). The two 699 amino acid predicted protein sequences differ in two residues at positions 341 (Gly or Cys within the repression domain) and 448 (Pro or Ser) and show over 80, 70 and 60% homology to maize, rice and oat VP1 proteins respectively. Expression analysis of the sorghum vp1 gene in the two lines shows a slightly higher level of vp1 mRNA in the embryos susceptible to PHS than in those resistant to PHS during embryogenesis. However, timing of expression was different between these genotypes during this developmental process. Whereas for the former the main peak of expression was observed at 20 days after pollination (DAP), the peak in the latter was found at later developmental stages when seed maturation was almost complete. Under favourable germination conditions and in the presence of fluridone (an inhibitor of ABA biosynthesis), sorghum vp1 mRNA showed to be consistently correlated with sensitivity to ABA but not with ABA content and dormancy.

  16. Gas-Grain Models for Interstellar Anion Chemistry

    Science.gov (United States)

    Cordiner, M. A.; Charnely, S. B.

    2012-01-01

    Long-chain hydrocarbon anions C(sub n) H(-) (n = 4, 6, 8) have recently been found to be abundant in a variety of interstellar clouds. In order to explain their large abundances in the denser (prestellar/protostellar) environments, new chemical models are constructed that include gas-grain interactions. Models including accretion of gas-phase species onto dust grains and cosmic-ray-induced desorption of atoms are able to reproduce the observed anion-to-neutral ratios, as well as the absolute abundances of anionic and neutral carbon chains, with a reasonable degree of accuracy. Due to their destructive effects, the depletion of oxygen atoms onto dust results in substantially greater polyyne and anion abundances in high-density gas (with n(sub H2) approx > / cubic cm). The large abundances of carbon-chain-bearing species observed in the envelopes of protostars such as L1527 can thus be explained without the need for warm carbon-chain chemistry. The C6H(-) anion-to-neutral ratio is found to be most sensitive to the atomic O and H abundances and the electron density. Therefore, as a core evolves, falling atomic abundances and rising electron densities are found to result in increasing anion-to-neutral ratios. Inclusion of cosmic-ray desorption of atoms in high-density models delays freeze-out, which results in a more temporally stable anion-to-neutral ratio, in better agreement with observations. Our models include reactions between oxygen atoms and carbon-chain anions to produce carbon-chain-oxide species C6O, C7O, HC6O, and HC7O, the abundances of which depend on the assumed branching ratios for associative electron detachment

  17. Differential access to phosphorus pools of an Oxisol by mycorrhizal and non-mycorrhizal maize

    NARCIS (Netherlands)

    Cardoso, I.M.; Boddington, C.L.; Janssen, B.H.; Oenema, O.; Kuyper, T.W.

    2006-01-01

    This study investigated whether arbuscular mycorrhizal fungi (AMF) could take up phosphorus (P) from pools that are normally considered unavailable to plants. An aluminum (Al) resistant maize variety, inoculated with three species of Glomus or uninoculated, supplied with nutrient solution without P,

  18. Indium extraction by an acidic extractant associated or not with synergetic agents: importance of inorganic anions

    International Nuclear Information System (INIS)

    Goetz-Grandmont, G.; Taheri, M.; Brunette, J.P.; Leroy, M.J.F.

    1985-01-01

    Thermodynamic data are presented for indium extraction from low acidity media (pH value between 1 and 4) and at low concentration by a chelating extractant alone or associated to a solvatant or a lipophylic ammonium salt. Modifications in the nature and/or concentration of inorganic anions can transform the extraction process and allow to change metal distribution between phases [fr

  19. Host Status of Five Weed Species and Their Effects on Pratylenchus zeae Infestation of Maize.

    Science.gov (United States)

    Jordaan, E M; De Waele, D

    1988-10-01

    The host suitability of five of the most common weed species occurring in maize (Zea mays L.) fields in South Africa to Pratylenchus zeae was tested. Based on the number of nematodes per root unit, mealie crotalaria (Crotalaria sphaerocarpa) was a good host; goose grass (Eleusine indica), common pigweed (Amaranthus hybridus), and thorn apple (Datura stramonium) were moderate hosts; and khaki weed (Tagetes minuta) was a poor host. Only the root residues of khaki weed suppressed the P. zeae infestation of subsequently grown maize. When goose grass, khaki weed, and mealie crotalaria were grown in association with maize in soil infested with P. zeae, goose grass and khaki weed severely suppressed maize root development; this resulted in a low number of nematodes per maize root system and a high number of nematodes per maize root unit. Mealie crotalaria did not restrict maize root growth and did not affect nematode densities per maize root system or maize root unit. Special attention should be given to the control of mealie crotalaria, which is a good host for P. zeae, and goose grass, which, in addition to its ability to compete with maize, is also a suitable host for P. zeae.

  20. Mapping and validation of quantitative trait loci for resistance to Cercospora zeae-maydis infection in tropical maize (Zea mays L.).

    Science.gov (United States)

    Pozar, Gilberto; Butruille, David; Silva, Heyder Diniz; McCuddin, Zoe Patterson; Penna, Julio Cesar Viglioni

    2009-02-01

    Breeding for resistance to gray leaf spot, caused by Cercospora zeae-maydis (Cz) is paramount for many maize environments, in particular under warm and humid growing conditions. In this study, we mapped and characterized quantitative trait loci (QTL) involved in the resistance of maize against Cz. We confirmed the impact of the QTL on disease severity using near-isogenic lines (NILs), and estimated their effects on three major agronomic traits using their respective near isogenic hybrids (NIHs), which we obtained by crossing the NILs with an inbred from a complementary heterotic pool. We further validated three of the four QTL that were mapped using the Multiple Interval Mapping approach and showed LOD values>2.5. NILs genotype included all combinations between favorable alleles of the two QTL located in chromosome 1 (Q1 in bin 1.05 and Q2 in bin 1.07), and the allele in chromosome 3 (Q3 in bin 3.07). Each of the three QTL separately significantly reduced the severity of Cz. However, we found an unfavorable epistatic interaction between Q1 and Q2: presence of the favorable allele at one of the QTL allele effectively nullified the effect of the favorable allele at the other. In contrast, the interaction between Q2 and Q3 was additive, promoting the reduction of the severity to a greater extent than the sum of their individual effects. When evaluating the NIH we found significant individual effects for Q1 and Q3 on gray leaf spot severity, for Q2 on stalk lodging and grain yield, and for Q3 on grain moisture and stalk lodging. We detected significant epitasis between Q1 and Q2 for grain moisture and between Q1 and Q3 for stalk lodging. These results suggest that the combination of QTL impacts the effectiveness of marker-assisted selection procedures in commercial product development programs.

  1. Gas-Phase Reactivity of Microsolvated Anions

    DEFF Research Database (Denmark)

    Thomsen, Ditte Linde

    the gas-phase α-effect. The experimental studies are performed by means of the flowing after glow selected ion flow tube technique, and these are supplemented by electronic structure calculations. The α-nucleophile employed is the microsolvated hydrogen peroxide anion whose reactivity is compared......Gas-phase studies of ion-molecule reactions shed light on the intrinsic factors that govern reactivity; and even solvent effects can be examined in the gasphase environment by employing microsolvated ions. An area that has received considerable attention with regard to the interplay between...... to that of a series of microsolvated oxygen centered anions. The association of the nucleophiles with a single water or methanol molecule allows the α-effect to be observed in the SN2 reaction with methyl chloride; this effect was not apparent in the reactions of the unsolvated anions. The results suggest...

  2. Assessment of maize stem borer damage on hybrid maize varieties in Chitwan, Nepal

    Directory of Open Access Journals (Sweden)

    Buddhi Bahadur Achhami

    2015-12-01

    Full Text Available Maize is the second most important cereal crop in Nepal. However, national figure of grain production still remains below than the world's average grain production per unit area. Thus, this experiment was designed to determine the suitable time of maize planting, and to assess the peak period of one of the major insects, maize stem borer, in Chitwan condition. The results showed that plant damage percentage as per the maize planting month varies significantly, and the average plant damage percentage by stem borer was up to 18.11%. Length of the feeding tunnel in maize stem was significantly higher in January than July. In case of exit holes made by borer counted more than four holes per plant that were planted in the month of January. All in all, except the tunnel length measurement per plant, we observed similar pattern in other borer damage parameters such as exit whole counts and plant damage percentage within the tested varieties. Stem borer damage was not significantly affect on grain yield.

  3. Associations between depressive symptoms and insulin resistance

    DEFF Research Database (Denmark)

    Adriaanse, M C; Dekker, J M; Nijpels, G

    2006-01-01

    AIMS/HYPOTHESIS: The association between depression and insulin resistance has been investigated in only a few studies, with contradictory results reported. The aim of this study was to determine whether the association between symptoms of depression and insulin resistance varies across glucose...... established type 2 diabetes mellitus. Main outcome measures were insulin resistance defined by the homeostasis model assessment for insulin resistance (HOMA-IR) and symptoms of depression using the Centre for Epidemiologic Studies Depression Scale (CES-D). RESULTS: In the total sample, we found a weak.......942). The association between depressive symptoms and insulin resistance was similar for men and women. CONCLUSIONS/INTERPRETATION: We found only weak associations between depressive symptoms and insulin resistance, which did not differ among different glucose metabolism subgroups or between men and women....

  4. Effects of airborne black carbon pollution on maize

    Science.gov (United States)

    Illes, Bernadett; Anda, Angela; Soos, Gabor

    2013-04-01

    The black carbon (BC) changes the radiation balance of the Earth and contributes to global warming. The airborne BC deposited on the surface of plant, changing the radiation balance, water balance and the total dry matter (TDM) content of plant. The objective of our study was to investigate the impact of soot originated from motor vehicle exhaust on maize. The field experiment was carried out in Keszthely Agrometeorological Research Station (Hungary) in three consecutive years (2010, 2011, 2012) of growing season. The test plant was the maize hybrid Sperlona (FAO 340) with short growing season. The BC was chemically "pure", which means that it is free any contaminants (e.g. heavy metals). The BC was coming from the Hankook Tyre Company (Dunaújváros, Hungary), where used that for improve the wear resistance of tires. We used a motorised sprayer of SP 415 type to spray the BC onto the leaf surface. The leaf area index (LAI) was measured each week on the same 12 sample maize in each treatment using an LI 3000A automatic planimeter (LI-COR, Lincoln, NE). Albedo was measured by pyranometers of the CMA-11 type (Kipp & Zonen, Vaisala), what we placed the middle of the plot of 0.3 ha. The effects of BC were studied under two different water supplies: evapotranspirometers of Thornthwaite type were used for "ad libitum" treatment and rainfed treatment in field plots. In 2010 and 2012, a big difference was not observed in the case of LAI in the effects of BC. However, in 2011 there was a significant difference. The LAI of the BC polluted maize was higher (10-15%, P<0.05), than the LAI of the control maize in the rainfed plot and in the ET chambers, respectively. The albedo of the BC contaminated maize decreased (15-30%, P<0.05) in all three years. We also detected that the green plant surface of maize increased on BC contaminated treatment. These results may suggest that the plant is able to absorb the additional carbon source through the leaves. The albedo decreased

  5. Effects of 90-Day Feeding of Transgenic Maize BT799 on the Reproductive System in Male Wistar Rats

    Directory of Open Access Journals (Sweden)

    Qian-ying Guo

    2015-12-01

    Full Text Available BT799 is a genetically modified (GM maize plant that expresses the Cry1Ac gene from Bacillus thuringiensis (Bt. The Cry1Ac gene was introduced into maize line Zhen58 to encode the Bt crystal protein and thus produce insect-resistant maize BT799. Expression of Bt protein in planta confers resistance to Lepidopteran pests and corn rootworms. The present study was designed to investigate any potential effects of BT799 on the reproductive system of male rats and evaluate the nutritional value of diets containing BT799 maize grain in a 90-day subchronic rodent feeding study. Male Wistar rats were fed with diets containing BT799 maize flours or made from its near isogenic control (Zhen58 at a concentration of 84.7%, nutritionally equal to the standard AIN-93G diet. Another blank control group of male rats were treated with commercial AIN-93G diet. No significant differences in body weight, hematology and serum chemistry results were observed between rats fed with the diets containing transgenic BT799, Zhen58 and the control in this 13-week feeding study. Results of serum hormone levels, sperm parameters and relative organ/body weights indicated no treatment-related side effects on the reproductive system of male rats. In addition, no diet-related changes were found in necropsy and histopathology examinations. Based on results of the current study, we did not find any differences in the parameters tested in our study of the reproductive system of male rats between BT799 and Zhen58 or the control.

  6. Anions in Cometary Comae

    Science.gov (United States)

    Charnley, Steven B.

    2011-01-01

    The presence of negative ions (anions) in cometary comae is known from Giotto mass spectrometry of IP/Halley. The anions 0-, OH-, C-, CH- and CN- have been detected, as well as unidentified anions with masses 22-65 and 85-110 amu (Chaizy et al. 1991). Organic molecular anions are known to have a significant impact on the charge balance of interstellar clouds and circumstellar envelopes and have been shown to act as catalysts for the gas-phase synthesis of larger hydrocarbon molecules in the ISM, but their importance in cometary comae has not yet been explored. We present details of the first attempt to model the chemistry of anions in cometary comae. Based on the combined chemical and hydro dynamical model of Rodgers & Charnley (2002), we investigate the role of large carbon-chain anions in cometary coma chemistry. We calculate the effects of these anions on coma thermodynamics, charge balance and examine their impact on molecule formation.

  7. Influence of seed priming and nitrogen application on the growth and development of maize seedlings in saline conditions

    International Nuclear Information System (INIS)

    Cao, D.; Zhang, Y.; Zhang, Y.; Guan, B.

    2018-01-01

    Seed priming and nitrogen application can promote plant tolerance and resistance to salt stress. To explore the combined effects of these two factors on the growth of salt-stressed seedlings, four treatments (priming + nitrogen application, PN; priming + no nitrogen application, P; unprimed + nitrogen application, UPN; and control treatment unprimed + no nitrogen application, UP) were applied to evaluate the responses of plant morphology, antioxidase systems, physiological and biochemical parameters of the maize seedlings under different concentrations of salt stress (0, 100, 200, and 300 mM). The results indicated that under salt stress, the priming treatment facilitated the growth of seedlings of root and stems, increased the amount of osmoregulatory substances, and enhanced the antioxidase activity and resistance of the maize seedlings. After nitrogen application during the maize growth stage, the growth of young leaves was greatly promoted along with an increase in the soluble protein and chlorophyll content. The combination of seed priming and nitrogen application significantly improved the plant growth, antioxidase activities and physiological and biochemical parameters. (author)

  8. Maize cob losses and their effects on the poverty status of maize

    African Journals Online (AJOL)

    This study analysed fresh maize cob losses and its effect on the poverty status of maize farmers in Edo State,. Nigeria. The specific .... is the poverty gap for ... Total cost. 162,367.48. 100.00. Returns. Total expected yield (N). 327,966.63. _.

  9. The iojap gene in maize

    Energy Technology Data Exchange (ETDEWEB)

    Martienssen, Robert

    2001-12-01

    The classical maize mutant iojap (Iodent japonica) has variegated green and white leaves. Green sectors have cells with normal chloroplasts whereas white sectors have cells where plastids fail to differentiate. These mutant plastids, when transmitted through the female gametophyte, do not recover in the presence of wild type Iojap. We cloned the Ij locus, and we have investigated the mechanism of epigenetic inheritance and phenotypic expression. More recently, a modifier of this type of variegation, ''Inhibitor of striate'', has also been cloned. Both the iojap and inhibitor of striate proteins have homologs in bacteria and are members of ancient conserved families found in multiple species. These tools can be used to address fundamental questions of inheritance and variegation associated with this classical conundrum of maize genetics. Since the work of Rhoades there has been considerable speculation concerning the nature of the Iojap gene product, the origin of leaf variegation and the mechanism behind the material inheritance of defective plastids. This has made Iojap a textbook paradigm for cytoplasmic inheritance and nuclear-organellar interaction for almost 50 years. Cloning of the Iojap gene in maize, and homologs in other plants and bacteria, provides a new means to address the origin of heteroplastidity, variegation and cytoplasmic inheritance in higher plants.

  10. MaizeGDB: The Maize Model Organism Database for Basic, Translational, and Applied Research

    OpenAIRE

    Lawrence, Carolyn J.; Harper, Lisa C.; Schaeffer, Mary L.; Sen, Taner Z.; Seigfried, Trent E.; Campbell, Darwin A.

    2008-01-01

    In 2001 maize became the number one production crop in the world with the Food and Agriculture Organization of the United Nations reporting over 614 million tonnes produced. Its success is due to the high productivity per acre in tandem with a wide variety of commercial uses. Not only is maize an excellent source of food, feed, and fuel, but also its by-products are used in the production of various commercial products. Maize's unparalleled success in agriculture stems from basic research, th...

  11. Genetic resources in maize breeding

    Directory of Open Access Journals (Sweden)

    Anđelković Violeta

    2017-01-01

    Full Text Available Maize, wheat and rice are the most important cereals grown in the world. It is predicted that by 2025 maize is likely to become the crop with the greatest production globally. Conservation of maize germplasm provides the main resources for increased food and feed production. Conservation in gene banks (ex-situ is dominant strategy for maize conservation. More than 130 000 maize accessions, e.g. about 40% of total number, are stored in ten largest gene banks worldwide and Maize Research Institute Zemun Polje (MRIZP gene bank, with about 6000 accessions, is among them. Organized collecting missions started in 1961. in the former Yugoslavian territory, and up today, more than 2000 local maize landraces were stored. Pre-breeding activities that refer to identification of desirable traits from unadapted germplasm within genebank, result in materials expected to be included in breeding programs. Successful examples are LAMP, GEM and GENRES projects. At the end of XX century, at MRIZP genebank two pre-breeding activities were undertaken: eco-core and elite-core collections were created and landraces fulfilled particular criteria were chosen. In the last decade, MRIZP genebank collection was used for identification of sources for drought tolerance and improved grain quality. According to agronomic traits and general combining ability, two mini-core collections were created and included in commercial breeding programs.

  12. Field screening of experimental corn hybrids and inbred lines for multiple ear-feeding insect resistance.

    Science.gov (United States)

    Ni, Xinzhi; Xu, Wenwei; Krakowsky, Matthew D; Buntin, G David; Brown, Steve L; Lee, R Dewey; Coy, Anton E

    2007-10-01

    Identifying and using native insect resistance genes is the core of integrated pest management. In this study, 10 experimental corn, Zea mays L., hybrids and 10 inbred lines were screened for resistance to major ear-feeding insects in the southeastern Coastal Plain region of the United States during 2004 and 2005. Ear-feeding insect damage was assessed at harvest by visual damage rating for the corn earworm, Helicoverpa zea (Boddie), and by the percentage of kernels damaged by the maize weevil, Sitophilus zeamais Motschulsky, and stink bugs [combination of Euschistus servus (Say) and southern green stink bug, Nezara viridula (L.)]. Among the eight inbred lines and two control populations examined, C3S1B73-5b was resistant to corn earworm, maize weevil, and stink bugs. In contrast, C3S1B73-4 was resistant to corn earworm and stink bugs, but not to maize weevil. In a similar manner, the corn hybrid S1W*CML343 was resistant to all three ear-feeding insects, whereas hybrid C3S1B73-3*Tx205 was resistant to corn earworm and maize weevil in both growing seasons, but susceptible to stink bugs in 2005. The silk-feeding bioassay showed that corn earworm developed better on corn silk than did fall armyworm. Among all phenotypic traits examined (i.e., corn ear size, husk extension, and husk tightness), only corn ear size was negatively correlated to corn earworm damage in the inbred lines examined, whereas only husk extension (i.e., coverage) was negatively correlated to both corn earworm and maize weevil damage on the experimental hybrids examined. Such information could be used to establish a baseline for developing agronomically elite corn germplasm that confers multiple ear-feeding insect resistance.

  13. Maize lethal necrosis (MLN), an emerging threat to maize-based food security in sub-Saharan Africa

    Science.gov (United States)

    In sub-Saharan Africa, maize is a staple food and key determinant of food security for smallholder farming communities. Pest and disease outbreaks are key constraints to maize productivity. In September 2011, a serious disease outbreak, later diagnosed as maize lethal necrosis (MLN), was reported on...

  14. Fusarium diseases of maize associated with mycotoxin contamination of agricultural products intended to be used for food and feed.

    Science.gov (United States)

    Oldenburg, Elisabeth; Höppner, Frank; Ellner, Frank; Weinert, Joachim

    2017-08-01

    Infections of maize with phytopathogenic and toxinogenic Fusarium spp. may occur throughout the cultivation period. This can cause different types of diseases in vegetative and generative organs of the plant. Along with these infections, mycotoxins are often produced and accumulated in affected tissues, which could pose a significant risk on human and animal health when entering the food and feed chain. Most important fungal species infecting European maize belong to the Fusarium sections Discolour and Liseola, the first being more prevalent in cooler and humid climate regions than the second predominating in warmer and dryer areas. Coexistence of several Fusarium spp. pathogens in growing maize under field conditions is the usual case and may lead to multi-contamination with mycotoxins like trichothecenes, zearalenone and fumonisins. The pathways how the fungi gain access to the target organs of the plant are extensively described in relation to specific symptoms of typical rot diseases regarding ears, kernels, rudimentary ears, roots, stem, leaves, seed and seedlings. Both Gibberella and Fusarium ear rots are of major importance in affecting the toxinogenic quality of grain or ear-based products as well as forage maize used for human or animal nutrition. Although rudimentary ears may contain high amounts of Fusarium toxins, the contribution to the contamination of forage maize is minor due to their small proportion on the whole plant dry matter yield. The impact of foliar diseases on forage maize contamination is regarded to be low, as Fusarium infections are restricted to some parts on the leaf sheaths and husks. Mycotoxins produced in rotted basal part of the stem may contribute to forage maize contamination, but usually remain in the stubbles after harvest. As the probability of a more severe disease progression is increasing with a prolonged cultivation period, maize should be harvested at the appropriate maturity stage to keep Fusarium toxin contamination as

  15. The proteome and phosphoproteome of maize pollen uncovers fertility candidate proteins.

    Science.gov (United States)

    Chao, Qing; Gao, Zhi-Fang; Wang, Yue-Feng; Li, Zhe; Huang, Xia-He; Wang, Ying-Chun; Mei, Ying-Chang; Zhao, Biligen-Gaowa; Li, Liang; Jiang, Yu-Bo; Wang, Bai-Chen

    2016-06-01

    Maize is unique since it is both monoecious and diclinous (separate male and female flowers on the same plant). We investigated the proteome and phosphoproteome of maize pollen containing modified proteins and here we provide a comprehensive pollen proteome and phosphoproteome which contain 100,990 peptides from 6750 proteins and 5292 phosphorylated sites corresponding to 2257 maize phosphoproteins, respectively. Interestingly, among the total 27 overrepresented phosphosite motifs we identified here, 11 were novel motifs, which suggested different modification mechanisms in plants compared to those of animals. Enrichment analysis of pollen phosphoproteins showed that pathways including DNA synthesis/chromatin structure, regulation of RNA transcription, protein modification, cell organization, signal transduction, cell cycle, vesicle transport, transport of ions and metabolisms, which were involved in pollen development, the following germination and pollen tube growth, were regulated by phosphorylation. In this study, we also found 430 kinases and 105 phosphatases in the maize pollen phosphoproteome, among which calcium dependent protein kinases (CDPKs), leucine rich repeat kinase, SNF1 related protein kinases and MAPK family proteins were heavily enriched and further analyzed. From our research, we also uncovered hundreds of male sterility-associated proteins and phosphoproteins that might influence maize productivity and serve as targets for hybrid maize seed production. At last, a putative complex signaling pathway involving CDPKs, MAPKs, ubiquitin ligases and multiple fertility proteins was constructed. Overall, our data provides new insight for further investigation of protein phosphorylation status in mature maize pollen and construction of maize male sterile mutants in the future.

  16. Does cypermethrin affect enzyme activity, respiration rate and walking behavior of the maize weevil (Sitophilus zeamais)?

    Institute of Scientific and Technical Information of China (English)

    Ronnie Von Santos Veloso; Eliseu José G.Pereira; Raul Narciso C.Guedes; Maria Goreti A.Oliveira

    2013-01-01

    Insecticides cause a range of sub-lethal effects on targeted insects,which are frequently detrimental to them.However,targeted insects are able to cope with insecticides within sub-lethal ranges,which vary with their susceptibility.Here we assessed the response of three strains of the maize weevil Sitophilus zeamais Motschulsky (Coleoptera:Curculionidae) to sub-lethal exposure to the pyrethoid insecticide cypermethrin.We expected enzyme induction associated with cypermethrin resistance since it would aid the resistant insects in surviving such exposure.Lower respiration rate and lower activity were also expected in insecticide-resistant insects since these traits are also likely to favor survivorship under insecticide exposure.Curiously though,cypermethrin did not affect activity of digestive and energy metabolism enzymes,and even reduced the activity of some enzymes (particularly for cellulase and cysteine-proteinase activity in this case).There was strain variation in response,which may be (partially) related to insecticide resistance in some strains.Sub-lethal exposure to cypermethrin depressed proteolytic and mainly cellulolytic activity in the exposed insects,which is likely to impair their fitness.However,such exposure did not affect respiration rate and walking behavior of the insects (except for the susceptible strain where walking activity was reduced).Walking activity varies with strain and may minimize insecticide exposure,which should be a concern,particularly if associated with (physiological) insecticide resistance.

  17. Adaptation of maize to temperate climates: mid-density genome-wide association genetics and diversity patterns reveal key genomic regions, with a major contribution of the Vgt2 (ZCN8 locus.

    Directory of Open Access Journals (Sweden)

    Sophie Bouchet

    Full Text Available The migration of maize from tropical to temperate climates was accompanied by a dramatic evolution in flowering time. To gain insight into the genetic architecture of this adaptive trait, we conducted a 50K SNP-based genome-wide association and diversity investigation on a panel of tropical and temperate American and European representatives. Eighteen genomic regions were associated with flowering time. The number of early alleles cumulated along these regions was highly correlated with flowering time. Polymorphism in the vicinity of the ZCN8 gene, which is the closest maize homologue to Arabidopsis major flowering time (FT gene, had the strongest effect. This polymorphism is in the vicinity of the causal factor of Vgt2 QTL. Diversity was lower, whereas differentiation and LD were higher for associated loci compared to the rest of the genome, which is consistent with selection acting on flowering time during maize migration. Selection tests also revealed supplementary loci that were highly differentiated among groups and not associated with flowering time in our panel, whereas they were in other linkage-based studies. This suggests that allele fixation led to a lack of statistical power when structure and relatedness were taken into account in a linear mixed model. Complementary designs and analysis methods are necessary to unravel the architecture of complex traits. Based on linkage disequilibrium (LD estimates corrected for population structure, we concluded that the number of SNPs genotyped should be at least doubled to capture all QTLs contributing to the genetic architecture of polygenic traits in this panel. These results show that maize flowering time is controlled by numerous QTLs of small additive effect and that strong polygenic selection occurred under cool climatic conditions. They should contribute to more efficient genomic predictions of flowering time and facilitate the dissemination of diverse maize genetic resources under a wide

  18. Comparative diversity of arthropods on Bt maize and non-Bt maize in two different cropping systems in South Africa.

    Science.gov (United States)

    Truter, J; Van Hamburg, H; Van Den Berg, J

    2014-02-01

    The biodiversity of an agroecosystem is not only important for its intrinsic value but also because it influences ecological functions that are vital for crop production in sustainable agricultural systems and the surrounding environment. A concern about genetically modified (GM) crops is the potential negative impact that such crops could have on diversity and abundance of nontarget organisms, and subsequently on ecosystem functions. Therefore, it is essential to assess the potential environmental risk of the release of a GM crop and to study its effect on species assemblages within that ecosystem. Assessment of the impact of Bt maize on the environment is hampered by the lack of basic checklists of species present in maize agroecosystems. The aims of the study were to compile a checklist of arthropods that occur on maize in South Africa and to compare the diversity and abundance of arthropods and functional groups on Bt maize and non-Bt maize. Collections of arthropods were carried out during two growing seasons on Bt maize and non-Bt maize plants at two localities. Three maize fields were sampled per locality during each season. Twenty plants, each of Bt maize and non-Bt maize, were randomly selected from the fields at each site. The arthropods collected during this study were classified to morphospecies level and grouped into the following functional groups: detritivores, herbivores, predators, and parasitoids. Based on feeding strategy, herbivores and predators were further divided into sucking herbivores or predators (piercing-sucking mouthparts) and chewing herbivores or predators (chewing mouthparts). A total of 8,771 arthropod individuals, comprising 288 morphospecies and presenting 20 orders, were collected. Results from this short-term study indicated that abundance and diversity of arthropods in maize and the different functional guilds were not significantly affected by Bt maize, either in terms of diversity or abundance.

  19. Effects of maize maturity at harvest and dietary proportion of maize silage on intake and performance of growing/finishing bulls

    DEFF Research Database (Denmark)

    Zaralis, K.; Nørgaard, P.; Helander, C.

    2014-01-01

    Whole-crop maize silage as forage in diets of finishing cattle can promote high intakes and thus, enhances animal performance. In the present study we evaluated the effect of whole-crop maize maturity at harvest and the proportion of maize-silage in diets of finishing bulls, on feed intake...... of treatments, involving two maturity stages of maize at harvest (i.e. dough stage or dent stage) and two maize silage proportions (i.e. 100% maize silage or 50% maize and 50% grass silage). The diets were offered ad libitum as total mixed rations (TMRs) with inclusion of concentrates (i.e. rolled barley; dried...... distillers’ grain plus soluble; cold-pressed rapeseed cake) in a 40% proportion on DM basis. All animals were slaughtered at a target body weight of 630 kg. Bulls fed on diets containing maize silage as sole forage achieved higher live-weight gain (P

  20. Breeding for Quality Protein Maize (QPM Varieties: A Review

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    Liliane N. Tandzi

    2017-11-01

    Full Text Available The nutritional evaluation of quality protein maize (QPM in feeding trials has proved its nutritional superiority over non-QPM varieties for human and livestock consumption. The present paper reviews some of the most recent achievements in development of QPM varieties using both conventional and molecular breeding under stressed and non-stressed environments. It is evident that numerous QPM varieties have been developed and released around the world over the past few decades. While the review points out some gaps in information or research efforts, challenges associated with adoption QPM varieties are highlighted and suggestions to overcome them are presented. The adoption of released varieties and challenges facing QPM production at the farmer level are also mentioned. Several breeding methods have been conventionally used to develop QPM varieties in stressed (drought, low soil nitrogen, resistance to grey leaf spot, Turcicum leaf blight, ear rot, and Striga and non-stressed environments. At least three genetic loci have been found to be implicated in controlling the levels of a protein synthesis factor correlated with lysine. They have been mapped on chromosomes 2, 4, and 7. While the use of molecular approaches will improve the efficiency and speed of variety development, the cost implications might limit the use of these technologies in the developing world. More emphasis should be given to breeding QPM for tolerance to environmental stresses, such as low soil pH, heat, and combined heat and drought stress. The post-harvest attack of QPM grains should also be considered. The adoption of QPM genotypes by farmers has been found to be limited mainly due to the minimal collaboration between maize breeders, farmers, agricultural extension workers, and other relevant stakeholders, as well as the need for isolating QPM varieties from normal maize. Therefore, there is need to use participatory plant breeding (PPB and/or participatory variety

  1. Capacidade de combinação em milho para resistência a Cercospora zeae-maydis Combining ability in maize for resistance to the Cercospora zeae-maydis

    Directory of Open Access Journals (Sweden)

    Marcio José Engelsing

    2011-03-01

    Full Text Available A resistência obtida pelo componente genético é um dos métodos mais eficientes de controle das doenças foliares da cultura do milho. Para avaliar a capacidade geral de combinação (CGC, capacidade específica de combinação (CEC, recíprocos, efeito materno e não-materno para resistência a Cercospora zeae-maydis, cinco linhagens (A, B, C, D e E foram cruzadas e os vinte híbridos obtidos foram utilizados em experimentos conduzidos em três ambientes. Foram avaliados a severidade da cercosporiose (CP no estádio fenológico R5 e o rendimento de grãos (RG na colheita. A análise dialélica demonstrou que ocorreu interação significativa (P The resistance due to genetic component is the most efficient method to control maize leaf diseases. The general combining ability (GCA, the specific combining ability (SCA, the reciprocal, the maternal and the not-maternal were evaluated for resistance to the Cercospora zeae-maydis at twenty hybrids. The hybrids were originated from crosses of five parents (A, B, C, D and E. The experiment was conducted in three environments. The resistance to Cercospora zeae-maydis was evaluated using grain yield (RG in the harvest and the severity of Gray leaf spot (GLS at physiological maturation, using the scale proposed by Agroceres (1996. The dialelic analysis demonstrated a significant interaction (P < 0,05 between hybrids versus places for GLS and RG. For the variable GLS, the GCA demonstrated that the best genitors had been D and E, different of that observed in grain yield (A and B. When considering SCA, the best hybrids combinations at the average places were AxD, BxE, AxE and BxC, and should be recommended the maintenance of these hybrids in the company breeding program.

  2. Cytotoxic mechanisms of hydrosulfide anion and cyanide anion in primary rat hepatocyte cultures

    International Nuclear Information System (INIS)

    Thompson, Rodney W.; Valentine, Holly L.; Valentine, William M.

    2003-01-01

    Hydrogen sulfide and hydrogen cyanide are known to compromise mitochondrial respiration through inhibition of cytochrome c oxidase and this is generally considered to be their primary mechanism of toxicity. Experimental studies and the efficiency of current treatment protocols suggest that H 2 S may exert adverse physiological effects through additional mechanisms. To evaluate the role of alternative mechanisms in H 2 S toxicity, the relative contributions of electron transport inhibition, uncoupling of mitochondrial respiration, and opening of the mitochondrial permeability transition pore (MPTP) to hydrosulfide and cyanide anion cytotoxicity in primary hepatocyte cultures were examined. Supplementation of hepatocytes with the glycolytic substrate, fructose, rescued hepatocytes from cyanide anion induced toxicity, whereas fructose supplementation increased hydrosulfide anion toxicity suggesting that hydrosulfide anion may compromise glycolysis in hepatocytes. Although inhibitors of the MPTP opening were protective for hydrosulfide anion, they had no effect on cyanide anion toxicity, consistent with an involvement of the permeability transition pore in hydrosulfide anion toxicity but not cyanide anion toxicity. Exposure of isolated rat liver mitochondria to hydrosulfide did not result in large amplitude swelling suggesting that if H 2 S induces the permeability transition it does so indirectly through a mechanism requiring other cellular components. Hydrosulfide anion did not appear to be an uncoupler of mitochondrial respiration in hepatocytes based upon the inability of oligomycin and fructose to protect hepatocytes from hydrosulfide anion toxicity. These findings support mechanisms additional to inhibition of cytochrome c oxidase in hydrogen sulfide toxicity. Further investigations are required to assess the role of the permeability transition in H 2 S toxicity, determine whether similar affects occur in other cell types or in vivo and evaluate whether this may

  3. Bacterial endophytes from wild maize suppress Fusarium graminearum in modern maize and inhibit mycotoxin accumulation

    Directory of Open Access Journals (Sweden)

    Walaa Kamel Mousa

    2015-10-01

    Full Text Available Wild maize (teosinte has been reported to be less susceptible to pests than their modern maize (corn relatives. Endophytes, defined as microbes that inhabit plants without causing disease, are known for their ability to antagonize plant pests and pathogens. We hypothesized that the wild relatives of modern maize may host endophytes that combat pathogens. Fusarium graminearum is the fungus that causes Gibberella Ear Rot (GER in modern maize and produces the mycotoxin, deoxynivalenol (DON. In this study, 215 bacterial endophytes, previously isolated from diverse maize genotypes including wild teosintes, traditional landraces and modern varieties, were tested for their ability to antagonize F. graminearum in vitro. Candidate endophytes were then tested for their ability to suppress GER in modern maize in independent greenhouse trials. The results revealed that three candidate endophytes derived from wild teosintes were most potent in suppressing F. graminearum in vitro and GER in a modern maize hybrid. These wild teosinte endophytes could suppress a broad spectrum of fungal pathogens of modern crops in vitro. The teosinte endophytes also suppressed DON mycotoxin during storage to below acceptable safety threshold levels. A fourth, less robust anti-fungal strain was isolated from a modern maize hybrid. Three of the anti-fungal endophytes were predicted to be Paenibacillus polymyxa, along with one strain of Citrobacter. Microscopy studies suggested a fungicidal mode of action by all four strains. Molecular and biochemical studies showed that the P. polymyxa strains produced the previously characterized anti-Fusarium compound, fusaricidin. Our results suggest that the wild relatives of modern crops may serve as a valuable reservoir for endophytes in the ongoing fight against serious threats to modern agriculture. We discuss the possible impact of crop evolution and domestication on endophytes in the context of plant defense.

  4. Agrobacterium- and Biolistic-Mediated Transformation of Maize B104 Inbred.

    Science.gov (United States)

    Raji, Jennifer A; Frame, Bronwyn; Little, Daniel; Santoso, Tri Joko; Wang, Kan

    2018-01-01

    Genetic transformation of maize inbred genotypes remains non-routine for many laboratories due to variations in cell competency to induce embryogenic callus, as well as the cell's ability to receive and incorporate transgenes into the genome. This chapter describes two transformation protocols using Agrobacterium- and biolistic-mediated methods for gene delivery. Immature zygotic embryos of maize inbred B104, excised from ears harvested 10-14 days post pollination, are used as starting explant material. Disarmed Agrobacterium strains harboring standard binary vectors and the biolistic gun system Bio-Rad PDS-1000/He are used as gene delivery systems. The herbicide resistant bar gene and selection agent bialaphos are used for identifying putative transgenic type I callus events. Using the step-by-step protocols described here, average transformation frequencies (number of bialaphos resistant T 0 callus events per 100 explants infected or bombarded) of 4% and 8% can be achieved using the Agrobacterium- and biolistic-mediated methods, respectively. An estimated duration of 16-21 weeks is needed using either protocol from the start of transformation experiments to obtaining putative transgenic plantlets with established roots. In addition to laboratory in vitro procedures, detailed greenhouse protocols for producing immature ears as transformation starting material and caring for transgenic plants for seed production are also described.

  5. Genetic analysis of central carbon metabolism unveils an amino acid substitution that alters maize NAD-dependent isocitrate dehydrogenase activity.

    Directory of Open Access Journals (Sweden)

    Nengyi Zhang

    2010-04-01

    Full Text Available Central carbon metabolism (CCM is a fundamental component of life. The participating genes and enzymes are thought to be structurally and functionally conserved across and within species. Association mapping utilizes a rich history of mutation and recombination to achieve high resolution mapping. Therefore, applying association mapping in maize (Zea mays ssp. mays, the most diverse model crop species, to study the genetics of CCM is a particularly attractive system.We used a maize diversity panel to test the CCM functional conservation. We found heritable variation in enzyme activity for every enzyme tested. One of these enzymes was the NAD-dependent isocitrate dehydrogenase (IDH, E.C. 1.1.1.41, in which we identified a novel amino-acid substitution in a phylogenetically conserved site. Using candidate gene association mapping, we identified that this non-synonymous polymorphism was associated with IDH activity variation. The proposed mechanism for the IDH activity variation includes additional components regulating protein level. With the comparison of sequences from maize and teosinte (Zea mays ssp. Parviglumis, the maize wild ancestor, we found that some CCM genes had also been targeted for selection during maize domestication.Our results demonstrate the efficacy of association mapping for dissecting natural variation in primary metabolic pathways. The considerable genetic diversity observed in maize CCM genes underlies heritable phenotypic variation in enzyme activities and can be useful to identify putative functional sites.

  6. Modelling the transport of carbonic acid anions through anion-exchange membranes

    International Nuclear Information System (INIS)

    Nikonenko, V.; Lebedev, K.; Manzanares, J.A.; Pourcelly, G.

    2003-01-01

    Electrodiffusion of carbonate and bicarbonate anions through anion-exchange membranes (AEM) is described on the basis of the Nernst-Planck equations taking into account coupled hydrolysis reactions in the external diffusion boundary layers (DBLs) and internal pore solution. The model supposes local electroneutrality as well as chemical and thermodynamic equilibrium. The transport is considered in three layers being an anion exchange membrane and two adjoining diffusion layers. A mechanism of competitive transport of HCO 3 - and CO 3 2- anions through the membrane which takes into account Donnan exclusion of H + ions is proposed. It is predicted that the pH of the depleting solution decreases and that of the concentrating solution increases during electrodialysis (ED). Eventual deviations from local electroneutrality and local chemical equilibrium are discussed

  7. Influence of the corn resistance gene Mv on the fitness of Peregrinus maidis (Hemiptera: Delphacidae) and on the transmission of maize mosaic virus (Rhabdoviridae: Nucleorhabdovirus).

    Science.gov (United States)

    Higashi, C H V; Brewbaker, J L; Bressan, A

    2013-08-01

    Crops that are resistant to pests and pathogens are cost-effective for the management of pests and diseases. A corn (Zea mays L.) breeding program conducted in Hawaii has identified a source of heritable resistance to maize mosaic virus (MMV) (Rhabdoviridae: Nucleorhabdovirus). This resistance is controlled by the gene Mv, which has been shown to have a codominant action. To date, no studies have examined whether the resistance associated with this gene affects only MMV or whether it also affects the insect vector, the corn planthopper Peregrinus maidis (Ashmead) (Hemiptera: Delphacidae). Here, we examined the life history of the corn planthopper and its ability to transmit MMV on near isogenic lines that were homozygous dominant (Mv/Mv), homozygous recessive (mv/mv), or heterozygous (Mv/mv) for the gene. A field trial was also conducted to study the colonization of the corn plants with different genotypes by the planthopper. Although field observations revealed slightly lower densities ofplanthoppers on corn with the genotype Mv/Mv than on the inbreds with the genotype mv/mv and their hybrids with the genotype Mv/mv, laboratory assays showed no effects of the gene on planthopper development, longevity, or fecundity. In the field, the corn lines Mv/Mv had a lower incidence of MMV-infected plants. However, in the greenhouse, the transmission of MMV to corn seedlings did not differ across the near isogenic lines, although the corn lines Mv/Mv showed a delayed onset of symptoms compared with the corn lines mv/mv and Mv/mv. The acquisition of MMV by corn planthoppers on the corn genotypes Mv/Mv and Mv/mv averaged 0.2, whereas the acquisition on the corn genotypes mv/mv averaged > 0.3. Our results show that the Mv gene does not influence the fitness of the planthopper vector, suggesting that it may confer resistance by other means, possibly by limiting virus replication or movement within the host plant.

  8. Preceramic maize from Paredones and Huaca Prieta, Peru.

    Science.gov (United States)

    Grobman, Alexander; Bonavia, Duccio; Dillehay, Tom D; Piperno, Dolores R; Iriarte, José; Holst, Irene

    2012-01-31

    Maize (Zea mays ssp. mays) is among the world's most important and ancient domesticated crops. Although the chronology of its domestication and initial dispersals out of Mexico into Central and South America has become more clear due to molecular and multiproxy archaeobotanical research, important problems remain. Among them is the paucity of information on maize's early morphological evolution and racial diversification brought about in part by the poor preservation of macrofossils dating to the pre-5000 calibrated years before the present period from obligate dispersal routes located in the tropical forest. We report newly discovered macrobotanical and microbotanical remains of maize that shed significant light on the chronology, land race evolution, and cultural contexts associated with the crop's early movements into South America and adaptation to new environments. The evidence comes from the coastal Peruvian sites of Paredones and Huaca Prieta, Peru; dates from the middle and late preceramic and early ceramic periods (between ca. 6700 and 3000 calibrated years before the present); and constitutes some of the earliest known cobs, husks, stalks, and tassels. The macrobotanical record indicates that a diversity of racial complexes characteristic of the Andean region emerged during the preceramic era. In addition, accelerator mass spectrometry radiocarbon determinations carried out directly on different structures of preserved maize plants strongly suggest that assays on burned cobs are more reliable than those on unburned cobs. Our findings contribute to knowledge of the early diffusion of maize and agriculture and have broader implications for understanding the development of early preindustrial human societies.

  9. Pyrethroid resistance in Sitophilus zeamais is associated with a mutation (T929I) in the voltage-gated sodium channel.

    Science.gov (United States)

    Araújo, Rúbia A; Williamson, Martin S; Bass, Christopher; Field, Linda M; Duce, Ian R

    2011-08-01

    The maize weevil, Sitophilus zeamais, is the most important pest affecting stored grain in Brazil and its control relies heavily on the use of insecticides. The intensive use of compounds such as the pyrethroids has led to the emergence of resistance, and previous studies have suggested that resistance to both pyrethroids and 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT) may result from reduced sensitivity of the insecticide target, the voltage-gated sodium channel. To identify the molecular mechanisms underlying pyrethroid resistance in S. zeamais, the domain II region of the voltage-gated sodium channel (para-orthologue) gene was amplified by PCR and sequenced from susceptible and resistant laboratory S. zeamais strains that were selected with a discriminating dose of DDT. A single point mutation, T929I, was found in the para gene of the resistant S. zeamais populations and its presence in individual weevils was strongly associated with survival after DDT exposure. This is the first identification of a target-site resistance mutation in S. zeamais and unusually it is a super-kdr type mutation occurring in the absence of the more common kdr (L1014F) substitution. A high-throughput assay based on TaqMan single nucleotide polymorphism genotyping was developed for sensitive detection of the mutation and used to screen field-collected strains of S. zeamais. This showed that the mutation is present at low frequency in field populations and is a useful tool for informing control strategies. © 2011 The Authors. Insect Molecular Biology © 2011 The Royal Entomological Society.

  10. "Achieving Mexico’s Maize Potential"

    OpenAIRE

    Antonio Turrent Fernández; Timothy A. Wise; Elise Garvey

    2012-01-01

    Rising agricultural prices, combined with growing import dependence, have driven Mexico’s food import bill over $20 billion per year and increased its agricultural trade deficit. Mexico imports one-third of its maize, overwhelmingly from the United States, but three million producers grow most of the country’s white maize, which is used primarily for tortillas and many other pluricultural products for human consumption. Yield gaps are large among the country’s small to medium-scale maize farm...

  11. Fusarium spp. and levels of fumonisins in maize produced by subsistence farmers in South Africa

    NARCIS (Netherlands)

    Ncube, E.; Flett, B.C.; Waalwijk, C.; Viljoen, A.

    2011-01-01

    Fusarium spp. produce fumonisins - mycotoxins that are of importance to maize production in South Africa. Fumonisins have been associated with human oesophageal cancer and cause various diseases in animals that are of concern to the animal feed industry. Maize samples, collected from subsistence

  12. Characterization of Asian Corn Borer Resistance to Bt Toxin Cry1Ie

    Directory of Open Access Journals (Sweden)

    Yueqin Wang

    2017-06-01

    Full Text Available A strain of the Asian corn borer (ACB, Ostrinia furnacalis (Guenée, has evolved >800-fold resistance to Cry1Ie (ACB-IeR after 49 generations of selection. The inheritance pattern of resistance to Cry1Ie in ACB-IeR strain and its cross-resistance to other Bt toxins were determined through bioassay by exposing neonates from genetic-crosses to toxins incorporated into the diet. The response of progenies from reciprocal F1 crosses were similar (LC50s: 76.07 vs. 74.32 μg/g, which suggested the resistance was autosomal. The effective dominance (h decreased as concentration of Cry1Ie increased. h was nearly recessive or incompletely recessive on Cry1Ie maize leaf tissue (h = 0.02, but nearly dominant or incompletely dominant (h = 0.98 on Cry1Ie maize silk. Bioassay of the backcross suggested that the resistance was controlled by more than one locus. In addition, the resistant strain did not perform cross-resistance to Cry1Ab (0.8-fold, Cry1Ac (0.8-fold, Cry1F (0.9-fold, and Cry1Ah (1.0-fold. The present study not only offers the manifestation for resistance management, but also recommends that Cry1Ie will be an appropriate candidate for expression with Cry1Ab, Cry1Ac, Cry1F, or Cry1Ah for the development of Bt maize.

  13. Characterization of Asian Corn Borer Resistance to Bt Toxin Cry1Ie.

    Science.gov (United States)

    Wang, Yueqin; Yang, Jing; Quan, Yudong; Wang, Zhenying; Cai, Wanzhi; He, Kanglai

    2017-06-07

    A strain of the Asian corn borer (ACB), Ostrinia furnacalis (Guenée), has evolved >800-fold resistance to Cry1Ie (ACB-IeR) after 49 generations of selection. The inheritance pattern of resistance to Cry1Ie in ACB-IeR strain and its cross-resistance to other Bt toxins were determined through bioassay by exposing neonates from genetic-crosses to toxins incorporated into the diet. The response of progenies from reciprocal F₁ crosses were similar (LC 50 s: 76.07 vs. 74.32 μg/g), which suggested the resistance was autosomal. The effective dominance ( h ) decreased as concentration of Cry1Ie increased. h was nearly recessive or incompletely recessive on Cry1Ie maize leaf tissue ( h = 0.02), but nearly dominant or incompletely dominant ( h = 0.98) on Cry1Ie maize silk. Bioassay of the backcross suggested that the resistance was controlled by more than one locus. In addition, the resistant strain did not perform cross-resistance to Cry1Ab (0.8-fold), Cry1Ac (0.8-fold), Cry1F (0.9-fold), and Cry1Ah (1.0-fold). The present study not only offers the manifestation for resistance management, but also recommends that Cry1Ie will be an appropriate candidate for expression with Cry1Ab, Cry1Ac, Cry1F, or Cry1Ah for the development of Bt maize.

  14. Zinc Resistance within Swine-Associated Methicillin-Resistant Staphylococcus aureus Isolates in the United States Is Associated with Multilocus Sequence Type Lineage.

    Science.gov (United States)

    Hau, Samantha J; Frana, Timothy; Sun, Jisun; Davies, Peter R; Nicholson, Tracy L

    2017-08-01

    Zinc resistance in livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) sequence type 398 (ST398) is primarily mediated by the czrC gene colocated with the mecA gene, encoding methicillin resistance, within the type V staphylococcal cassette chromosome mec (SCC mec ) element. Because czrC and mecA are located within the same mobile genetic element, it has been suggested that the use of zinc in feed as an antidiarrheal agent has the potential to contribute to the emergence and spread of methicillin-resistant S. aureus (MRSA) in swine, through increased selection pressure to maintain the SCC mec element in isolates obtained from pigs. In this study, we report the prevalence of the czrC gene and phenotypic zinc resistance in U.S. swine-associated LA-MRSA ST5 isolates, MRSA ST5 isolates from humans with no swine contact, and U.S. swine-associated LA-MRSA ST398 isolates. We demonstrated that the prevalence of zinc resistance in U.S. swine-associated LA-MRSA ST5 isolates was significantly lower than the prevalence of zinc resistance in MRSA ST5 isolates from humans with no swine contact and swine-associated LA-MRSA ST398 isolates, as well as prevalences from previous reports describing zinc resistance in other LA-MRSA ST398 isolates. Collectively, our data suggest that selection pressure associated with zinc supplementation in feed is unlikely to have played a significant role in the emergence of LA-MRSA ST5 in the U.S. swine population. Additionally, our data indicate that zinc resistance is associated with the multilocus sequence type lineage, suggesting a potential link between the genetic lineage and the carriage of resistance determinants. IMPORTANCE Our data suggest that coselection thought to be associated with the use of zinc in feed as an antimicrobial agent is not playing a role in the emergence of livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) ST5 in the U.S. swine population. Additionally, our data indicate

  15. Exploring maize-legume intercropping systems in Southwest Mexico

    NARCIS (Netherlands)

    Flores-Sanchez, D.; Pastor, A.V.; Lantinga, E.A.; Rossing, W.A.H.; Kropff, M.J.

    2013-01-01

    Maize yields in continuous maize production systems of smallholders in the Costa Chica, a region in Southwest Mexico, are low despite consistent inputs of fertilizers and herbicides. This study was aimed at investigating the prospects of intercropping maize (Zea mays L.) and maize-roselle (Hibiscus

  16. Genetic Diversity and Molecular Evolution of a Violaxanthin De-epoxidase Gene in Maize.

    Science.gov (United States)

    Xu, Jing; Li, Zhigang; Yang, Haorui; Yang, Xiaohong; Chen, Cuixia; Li, Hui

    2016-01-01

    Violaxanthin de-epoxidase (VDE) has a critical role in the carotenoid biosynthesis pathway, which is involved in protecting the photosynthesis apparatus from damage caused by excessive light. Here, a VDE gene in maize, ZmVDE1, was cloned and shown to have functional domains in common with the gramineous VDE protein. Candidate gene association analysis indicated that no polymorphic sites in ZmVDE1 were significant association with any of the examined carotenoid-related traits at P = 0.05 in an association panel containing 155 maize inbred lines. Nucleotide diversity analysis of VDE1 in maize and teosinte indicated that its exon had less genetic variation, consistent with the conserved function of VDE1 in plants. In addition, dramatically reduced nucleotide diversity, fewer haplotypes and a significantly negative parameter deviation for Tajima's D test of ZmVDE1 in maize and teosinte suggested that a potential selective force had acted across the ZmVDE1 locus. We further identified a 4.2 Mb selective sweep with low recombination surrounding the ZmVDE1 locus that resulted in severely reduced nucleotide diversity on chromosome 2. Collectively, natural selection and the conserved domains of ZmVDE1 might show an important role in the xanthophyll cycle of the carotenoid biosynthesis pathway.

  17. Genetic Diversity and Molecular Evolution of a Violaxanthin De-Epoxidase Gene in Maize

    Directory of Open Access Journals (Sweden)

    Jing Xu

    2016-07-01

    Full Text Available Violaxanthin de-epoxidase (VDE has a critical role in the carotenoid biosynthesis pathway, which is involved in protecting the photosynthesis apparatus from damage caused by excessive light. Here, a VDE gene in maize, ZmVDE1, was cloned and shown to have functional domains in common with the gramineous VDE protein. Candidate gene association analysis indicated that no polymorphic sites in ZmVDE1 were significant association with any of the examined carotenoid-related traits at P = 0.05 in an association panel containing 155 maize inbred lines. Nucleotide diversity analysis of VDE1 in maize and teosinte indicated that its exon had less genetic variation, consistent with the conserved function of VDE1 in plants. In addition, dramatically reduced nucleotide diversity, fewer haplotypes and a significantly negative parameter deviation for Tajima’s D test of ZmVDE1 in maize and teosinte suggested that a potential selective force had acted across the ZmVDE1 locus. We further identified a 4.2 Mb selective sweep with low recombination surrounding the ZmVDE1 locus that resulted in severely reduced nucleotide diversity on chromosome 2. Collectively, natural selection and the conserved domains of ZmVDE1 might show an important role in the xanthophyll cycle of the carotenoid biosynthesis pathway.

  18. Climatic and non-climatic drivers of spatiotemporal maize-area dynamics across the northern limit for maize production

    DEFF Research Database (Denmark)

    Odgaard, Mette Vestergaard; Bøcher, Peder Klith; Dalgaard, Tommy

    2011-01-01

    It is expected that the ongoing anthropogenic climate change will drive changes in agricultural production and its geographic distribution. Here, we assess the extent to which climate change is already driving spatiotemporal dynamics in maize production in Denmark. We use advanced spatial...... regression modeling with multi-model averaging to assess the extent to which the recent spatiotemporal dynamics of the maize area in Denmark are driven by climate (temperature as represented by maize heating units [MHU] and growing-season precipitation), climate change and non-climatic factors (cattle...... cultivation and cattle farming, probably reflecting a change to a more favorable climate for maize cultivation: in the beginning of the study period, northern areas were mostly too cold for maize cultivation, irrespective of cattle density, but this limitation has been diminishing as climate has warmed...

  19. A survey of pre-harvest ear rot diseases of maize and associated mycotoxins in south and central Zambia.

    Science.gov (United States)

    Mukanga, Mweshi; Derera, John; Tongoona, Pangirayi; Laing, Mark D

    2010-07-15

    Maize ear rots reduce grain yield and quality with implication on food security and health. Some of the pathogenic fungi produce mycotoxins in maize grain posing a health risk to humans and livestock. Unfortunately, the levels of ear rot and mycotoxin infection in grain produced by subsistence farmers in sub-Saharan countries are not known. A survey was thus conducted to determine the prevalence of the ear rot problem and levels of mycotoxins in maize grain. A total of 114 farmsteads were randomly sampled from 11 districts in Lusaka and southern provinces in Zambia during 2006. Ten randomly picked cobs were examined per farmstead and the ear rot disease incidence and severity were estimated on site. This was followed by the standard seed health testing procedures for fungal isolation in the laboratory. Results indicated that the dominant ear rots were caused by Fusarium and Stenocarpella. Incidence of Fusarium verticillioides ranged from 2 to 21%, whereas that of Stenocarpella maydis reached 37% on ear rot diseased maize grain. In addition, 2-7% F. verticillioides, and 3-18% Aspergillus flavus, respectively, were recovered from seemingly healthy maize grain. The mean rank of fungal species, from highest to lowest, was F. verticillioides, S. maydis, A. flavus, Fusarium graminearum, Aspergillus niger, Penicillium spp., Botrydiplodia spp., and Cladosporium spp. The direct competitive ELISA-test indicated higher levels of fumonisins than aflatoxins in pre-harvest maize grain samples. The concentration of fumonisins from six districts, and aflatoxin from two districts, was 10-fold higher than 2 ppm and far higher than 2 ppb maximum daily intake recommended by the FAO/WHO. The study therefore suggested that subsistence farmers and consumers in this part of Zambia, and maybe also in similar environments in sub-Saharan Africa, might be exposed to dangerous levels of mycotoxins due to the high levels of ear rot infections in maize grain. 2010 Elsevier B.V. All rights

  20. Harmonia axyridis (Coleoptera: Coccinellidae) Exhibits No Preference between Bt and Non-Bt Maize Fed Spodoptera frugiperda (Lepidoptera: Noctuidae)

    Science.gov (United States)

    Dutra, Carla C.; Koch, Robert L.; Burkness, Eric C.; Meissle, Michael; Romeis, Joerg; Hutchison, William D.; Fernandes, Marcos G.

    2012-01-01

    A recent shift in managing insect resistance to genetically engineered (GE) maize consists of mixing non-GE seed with GE seed known as “refuge in a bag”, which increases the likelihood of predators encountering both prey fed Bt and prey fed non-Bt maize. We therefore conducted laboratory choice-test feeding studies to determine if a predator, Harmonia axyridis, shows any preference between prey fed Bt and non-Bt maize leaves. The prey species was Spodoptera frugiperda, which were fed Bt maize (MON-810), expressing the single Cry1Ab protein, or non-Bt maize. The predators were third instar larvae and female adults of H. axyridis. Individual predators were offered Bt and non-Bt fed prey larvae that had fed for 24, 48 or 72 h. Ten and 15 larvae of each prey type were offered to third instar and adult predators, respectively. Observations of arenas were conducted at 1, 2, 3, 6, 15 and 24 h after the start of the experiment to determine the number and type of prey eaten by each individual predator. Prey larvae that fed on non-Bt leaves were significantly larger than larvae fed Bt leaves. Both predator stages had eaten nearly all the prey by the end of the experiment. However, in all combinations of predator stage and prey age, the number of each prey type consumed did not differ significantly. ELISA measurements confirmed the presence of Cry1Ab in leaf tissue (23–33 µg/g dry weight) and S. frugiperda (2.1–2.2 µg/g), while mean concentrations in H. axyridis were very low (0.01–0.2 µg/g). These results confirm the predatory status of H. axyridis on S. frugiperda and that both H. axyridis adults and larvae show no preference between prey types. The lack of preference between Bt-fed and non-Bt-fed prey should act in favor of insect resistance management strategies using mixtures of GE and non-GE maize seed. PMID:23024772

  1. Effect of planting density on root lodging resistance and its relationship to nodal root growth characteristics in maize (Zea mays L.)

    DEFF Research Database (Denmark)

    Liu, Shengqun; Song, Fengbin; Liu, Fulai

    2012-01-01

    Increase of planting density has been widely used to increase grain yield in maize. However, it may lead to higher risk of root lodging hence causing significant yield loss of the crop. The objective of this study was to investigate the effect of planting density on maize nodal root growth...

  2. Supramolecular Chemistry of Selective Anion Recognition for Anions of Environmental Relevance

    International Nuclear Information System (INIS)

    Sessler, Jonathan L.

    2007-01-01

    The major thrust of this project, led by the University of Kansas (Prof. Kristin Bowman-James), entails an exploration of the basic determinants of anion recognition and their application to the design, synthesis, and testing of novel sulfate extractants. A key scientific inspiration for the work comes from the need, codified in simple-to-appreciate terms by the Oak Ridge National Laboratory component of the team (viz. Dr. Bruce Moyer), for chemical entities that can help in the extractive removal of species that have low solubilities in borosilicate glass. Among such species, sulfate anion, has been identified as particularly insidious. Its presence interferes with the vitrification process, thus rendering the remediation of tank waste from, e.g., the Hanford site far more difficult and expensive. The availability of effective extractants, that would allow for the separation of separating sulfate from the major competing anions in the waste, especially nitrate, could allow for pre-vitrification removal of sulfate via liquid-liquid extraction. The efforts at The University of Texas, the subject of this report, have thus concentrated on the development of new sulfate receptors. These systems are designed to increase our basic understanding of anion recognition events and set the stage for the development of viable sulfate anion extractants. In conjunction with the Oak Ridge National Laboratory (ORNL) members of the research team, several of these new receptors were studied as putative extractants, with two of the systems being shown to act as promising synergists for anion exchange.

  3. A Comparative Study on the Uptake and Toxicity of Nickel Added in the Form of Different Salts to Maize Seedlings

    Directory of Open Access Journals (Sweden)

    Jing Nie

    2015-11-01

    Full Text Available In soil ecotoxicological studies, a toxic metal is usually added in the form of either an inorganic or organic salt with relatively high solubility. Nitrate, chloride, acetate, or sulfate are commonly considered as valid options for that aim. However, recent studies have shown that different salts of the same metal at the same cationic concentration may exhibit different toxicities to plants and soil organisms. This information should be considered when selecting data to use for developing toxicological criteria for soil environment. A comparative study was carried out to evaluate the toxicity of five nickel (Ni salts: NiCl2, NiSO4, Ni(II-citrate, Ni(CH3COO2, and Ni(II-EDTA (ethylenediaminetetraacetate, on maize seedlings. The plant metrics used were plant height, shoot and root biomass, leaf soluble sugars and starch, and the Ni contents of the shoots and roots. The results indicated that when Ni was added to the soil, toxicity varied with the selected anionic partner with the following toxicity ranking NiSO4 < Ni(CH3COO2 < Ni(II-citrate < NiCl2 < Ni(II-EDTA. Taking the plant-height metric as an example, the effective concentrations for 50% inhibition (EC50 were 3148 mg·kg−1 for NiSO4, 1315 mg·kg−1 for NiCl2, and 89 mg·kg−1 for Ni(II-EDTA. Compared with the Ni in the other salts, that in Ni(II-EDTA was taken up the most efficiently by the maize roots and, thus, resulted in the greatest toxic effects on the plants. Nickel generally reduced leaf soluble sugars, which indicated an effect on plant carbohydrate metabolism. The outcome of the study demonstrates that different salts of the same metal have quite different ecotoxicities. Therefore, the anionic counterpart of a potentially toxic metal cation must be taken into account in the development of ecotoxicological criteria for evaluating the soil environment, and a preferred approach of leaching soil to reduce the anionic partner should also be considered.

  4. Genetic Vulnerability and the Relationship of Commercial Germplasms of Maize in Brazil with the Nested Association Mapping Parents.

    Directory of Open Access Journals (Sweden)

    Luciano Rogério Braatz de Andrade

    Full Text Available A few breeding companies dominate the maize (Zea mays L. hybrid market in Brazil: Monsanto® (35%, DuPont Pioneer® (30%, Dow Agrosciences® (15%, Syngenta® (10% and Helix Sementes (4%. Therefore, it is important to monitor the genetic diversity in commercial germplasms as breeding practices, registration and marketing of new cultivars can lead to a significant reduction of the genetic diversity. Reduced genetic variation may lead to crop vulnerabilities, food insecurity and limited genetic gains following selection. The aim of this study was to evaluate the genetic vulnerability risk by examining the relationship between the commercial Brazilian maize germplasms and the Nested Association Mapping (NAM Parents. For this purpose, we used the commercial hybrids with the largest market share in Brazil and the NAM parents. The hybrids were genotyped for 768 single nucleotide polymorphisms (SNPs, using the Illumina Goldengate® platform. The NAM parent genomic data, comprising 1,536 SNPs for each line, were obtained from the Panzea data bank. The population structure, genetic diversity and the correlation between allele frequencies were analyzed. Based on the estimated effective population size and genetic variability, it was found that there is a low risk of genetic vulnerability in the commercial Brazilian maize germplasms. However, the genetic diversity is lower than those found in the NAM parents. Furthermore, the Brazilian germplasms presented no close relations with most NAM parents, except B73. This indicates that B73, or its heterotic group (Iowa Stiff Stalk Synthetic, contributed to the development of the commercial Brazilian germplasms.

  5. Genetic Vulnerability and the Relationship of Commercial Germplasms of Maize in Brazil with the Nested Association Mapping Parents.

    Science.gov (United States)

    Andrade, Luciano Rogério Braatz de; Fritsche Neto, Roberto; Granato, Ítalo Stefanine Correia; Sant'Ana, Gustavo César; Morais, Pedro Patric Pinho; Borém, Aluízio

    2016-01-01

    A few breeding companies dominate the maize (Zea mays L.) hybrid market in Brazil: Monsanto® (35%), DuPont Pioneer® (30%), Dow Agrosciences® (15%), Syngenta® (10%) and Helix Sementes (4%). Therefore, it is important to monitor the genetic diversity in commercial germplasms as breeding practices, registration and marketing of new cultivars can lead to a significant reduction of the genetic diversity. Reduced genetic variation may lead to crop vulnerabilities, food insecurity and limited genetic gains following selection. The aim of this study was to evaluate the genetic vulnerability risk by examining the relationship between the commercial Brazilian maize germplasms and the Nested Association Mapping (NAM) Parents. For this purpose, we used the commercial hybrids with the largest market share in Brazil and the NAM parents. The hybrids were genotyped for 768 single nucleotide polymorphisms (SNPs), using the Illumina Goldengate® platform. The NAM parent genomic data, comprising 1,536 SNPs for each line, were obtained from the Panzea data bank. The population structure, genetic diversity and the correlation between allele frequencies were analyzed. Based on the estimated effective population size and genetic variability, it was found that there is a low risk of genetic vulnerability in the commercial Brazilian maize germplasms. However, the genetic diversity is lower than those found in the NAM parents. Furthermore, the Brazilian germplasms presented no close relations with most NAM parents, except B73. This indicates that B73, or its heterotic group (Iowa Stiff Stalk Synthetic), contributed to the development of the commercial Brazilian germplasms.

  6. Genetic Vulnerability and the Relationship of Commercial Germplasms of Maize in Brazil with the Nested Association Mapping Parents

    Science.gov (United States)

    Fritsche Neto, Roberto; Granato, Ítalo Stefanine Correia; Sant’Ana, Gustavo César; Morais, Pedro Patric Pinho; Borém, Aluízio

    2016-01-01

    A few breeding companies dominate the maize (Zea mays L.) hybrid market in Brazil: Monsanto® (35%), DuPont Pioneer® (30%), Dow Agrosciences® (15%), Syngenta® (10%) and Helix Sementes (4%). Therefore, it is important to monitor the genetic diversity in commercial germplasms as breeding practices, registration and marketing of new cultivars can lead to a significant reduction of the genetic diversity. Reduced genetic variation may lead to crop vulnerabilities, food insecurity and limited genetic gains following selection. The aim of this study was to evaluate the genetic vulnerability risk by examining the relationship between the commercial Brazilian maize germplasms and the Nested Association Mapping (NAM) Parents. For this purpose, we used the commercial hybrids with the largest market share in Brazil and the NAM parents. The hybrids were genotyped for 768 single nucleotide polymorphisms (SNPs), using the Illumina Goldengate® platform. The NAM parent genomic data, comprising 1,536 SNPs for each line, were obtained from the Panzea data bank. The population structure, genetic diversity and the correlation between allele frequencies were analyzed. Based on the estimated effective population size and genetic variability, it was found that there is a low risk of genetic vulnerability in the commercial Brazilian maize germplasms. However, the genetic diversity is lower than those found in the NAM parents. Furthermore, the Brazilian germplasms presented no close relations with most NAM parents, except B73. This indicates that B73, or its heterotic group (Iowa Stiff Stalk Synthetic), contributed to the development of the commercial Brazilian germplasms. PMID:27780247

  7. Preparation of Two-Layer Anion-Exchange Poly(ethersulfone Based Membrane: Effect of Surface Modification

    Directory of Open Access Journals (Sweden)

    Lucie Zarybnicka

    2016-01-01

    Full Text Available The present work deals with the surface modification of a commercial microfiltration poly(ethersulfone membrane by graft polymerization technique. Poly(styrene-co-divinylbenzene-co-4-vinylbenzylchloride surface layer was covalently attached onto the poly(ethersulfone support layer to improve the membrane electrochemical properties. Followed by amination, a two-layer anion-exchange membrane was prepared. The effect of surface layer treatment using the extraction in various solvents on membrane morphological and electrochemical characteristics was studied. The membranes were tested from the point of view of water content, ion-exchange capacity, specific resistance, permselectivity, FT-IR spectroscopy, and SEM analysis. It was found that the two-layer anion-exchange membranes after the extraction using tetrahydrofuran or toluene exhibited smooth and porous surface layer, which resulted in improved ion-exchange capacity, electrical resistance, and permselectivity of the membranes.

  8. RESISTANCE TO POST-HARVEST MICROBIAL ROT IN YAM ...

    African Journals Online (AJOL)

    ACSS

    for resistance to internal rot, with Olordor and Kplondzo recording the lowest internal microbial rot, suggesting their potential in .... material. Dried maize stocks were then used to cover the pile of tubers. There were four .... effort in breeding for host plant resistance. Also, ... rot in Dioscorea species under all storage methods.

  9. Biodiversity of Fusarium species in Mexico associated with ear rot in maize, and their identification using a phylogenetic approach.

    Science.gov (United States)

    Morales-Rodríguez, Irma; Yañez-Morales, María de J; Silva-Rojas, Hilda V; García-de-Los-Santos, Gabino; Guzmán-de-Peña, Doralinda A

    2007-01-01

    Fusarium proliferatum, F. subglutinans, and F. verticillioides are known causes of ear and kernel rot in maize worldwide. In Mexico, only F. verticillioides and F. subglutinans, have been reported previously as causal agents of this disease. However, Fusarium isolates with different morphological characteristics to the species that are known to cause this disease were obtained in the Highland-Valley region of this country from symptomatic and symptomless ears of native and commercial maize genotypes. Moreover, while the morphological studies were not sufficient to identify the correct taxonomic position at the species level, analyses based in the Internal Transcribed Spacer region and the Nuclear Large Subunit Ribosomal partial sequences allowed for the identification of F. subglutinans, F. solani, and F. verticillioides, as well as four species (F. chlamydosporum, F. napiforme, F. poae, and F. pseudonygamai) that had not previously been reported to be associated with ear rot. In addition, F. napiforme and F. solani were absent from symptomless kernels. Phylogenetic analysis showed genetic changes in F. napiforme, and F. pseudonygamai isolates because they were not true clones, and probably constitute separate sibling species. The results of this study suggest that the biodiversity of Fusarium species involved in ear rot in Mexico is greater than that reported previously in other places in the world. This new knowledge will permit a better understanding of the relationship between all the species involved in ear rot disease and their relationship with maize.

  10. Some aspects of cultivation and utilization of waxy maize (Zea mays L. ssp. ceratina

    Directory of Open Access Journals (Sweden)

    Agnieszka Klimek-Kopyra

    2012-10-01

    Full Text Available This paper is a review of available literature on Zea mays L.ssp.ceratina. It contains information on the origin, cul- tivation and utilization of waxy maize in the world and can be a contribution to the development of new research on maize cultivation and starch processing technology. Maize, as an old and economically important cereal, played an enormous role in the ancient civilisations of the New World. Among the maize subspecies compared, Z. mays ssp. indurata and Z. mays ssp. indentata are now the most important in Poland. The subspecies Z. mays ssp. saccharata has a marginal role, while Z. mays ssp. ceratina has not been hitherto cultivated. Decisions to introduce the subspecies Z. mays ssp. ceratina into cultivation are based on different grounds, taking into account both agro-climatic conditions and industrial uses of grain processing products. The growing demand for maize grain, stimulated by the increased demand for maize starch and oil in the global market as raw materials that are important in food production, is an impulse for the development of agrobiological research. The development of the starch industry, associated with the demand for industrial starch, will probably contribute to increased interest in this subspecies in Central Europe, also including Poland. Waxy maize grain can be a major ingredient of high-energy feeds for livestock, replacing in this role the type of maize that has been grown for this purpose until now. A great advantage of waxy maize is its specific structure of starch, due to its unique and high amylopectin content (95-98%, which creates unlimited possibilities of industrial use. Currently, waxy maize acreage in Europe does not exceed 2% of the maize crop area in this continent.

  11. Identification and Characterization of microRNAs during Maize Grain Filling.

    Science.gov (United States)

    Jin, Xining; Fu, Zhiyuan; Lv, Panqing; Peng, Qian; Ding, Dong; Li, Weihua; Tang, Jihua

    2015-01-01

    The grain filling rate is closely associated with final grain yield of maize during the period of maize grain filling. To identify the key microRNAs (miRNAs) and miRNA-dependent gene regulation networks of grain filling in maize, a deep-sequencing technique was used to research the dynamic expression patterns of miRNAs at four distinct developmental grain filling stages in Zhengdan 958, which is an elite hybrid and cultivated widely in China. The sequencing result showed that the expression amount of almost all miRNAs was changing with the development of the grain filling and formed in seven groups. After normalization, 77 conserved miRNAs and 74 novel miRNAs were co-detected in these four samples. Eighty-one out of 162 targets of the conserved miRNAs belonged to transcriptional regulation (81, 50%), followed by oxidoreductase activity (18, 11%), signal transduction (16, 10%) and development (15, 9%). The result showed that miRNA 156, 393, 396 and 397, with their respective targets, might play key roles in the grain filling rate by regulating maize growth, development and environment stress response. The result also offered novel insights into the dynamic change of miRNAs during the developing process of maize kernels and assisted in the understanding of how miRNAs are functioning about the grain filling rate.

  12. Selection and characterization of resistance to the Vip3Aa20 protein from Bacillus thuringiensis in Spodoptera frugiperda.

    Science.gov (United States)

    Bernardi, Oderlei; Bernardi, Daniel; Horikoshi, Renato J; Okuma, Daniela M; Miraldo, Leonardo L; Fatoretto, Julio; Medeiros, Fernanda Cl; Burd, Tony; Omoto, Celso

    2016-09-01

    Spodoptera frugiperda is one the main target pests of maize events expressing Vip3Aa20 protein from Bacillus thuringiensis (Bt) in Brazil. In this study, we selected a resistant strain of S. frugiperda on Bt maize expressing Vip3Aa20 protein and characterized the inheritance and fitness costs of the resistance. The resistance ratio of the Vip3Aa20-resistant strain of S. frugiperda was >3200-fold. Neonates of the Vip3Aa20-resistant strain were able to survive and emerge as fertile adults on Vip3Aa20 maize, while larvae from susceptible and heterozygous strains did not survive. The inheritance of Vip3Aa20 resistance was autosomal recessive and monogenic. Life history studies to investigate fitness cost revealed an 11% reduction in the survival rate until adult stage and a ∼50% lower reproductive rate of the Vip3Aa20-resistant strain compared with susceptible and heterozygous strains. This is the first characterization of S. frugiperda resistance to Vip3Aa protein. Our results provide useful information for resistance management programs designed to prevent or delay resistance evolution to Vip3Aa proteins in S. frugiperda. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  13. Correlation and path analysis on main agronomic traits of progeny from space mutation maize inbred lines

    International Nuclear Information System (INIS)

    Zhang Caibo; Wu Zhangdong; Xu Wei; Rong Tingzhao; Cao Moju

    2013-01-01

    In order to discover and utilize the valuable resources from spaceflight mutagenesis maize offspring effectively, cross combinations derived from the offspring of three different maize inbred lines induced by space flight were made to investigate the yield and related agronomic traits under different environmental conditions. Correlation and path analysis indicated that the factors affecting the yield of combinations varied with different mutagenic materials and environmental effects with larger effect coming from environment. Therefore, different selection strategies should be chosen for different induced maize. For the 08-641 mutagenic material, the 100-kernel weight should be first considered to select while taking into account the number of rows per ear and kernels per row. For the RP125 mutagenic material, the kernels per row should be first selected, and then to select the 100-kernels weight and the number of rows per ear traits. For 18-599 mutagenic material, the 100-seed weight should be first selected, then the plant height, ear diameter, ear height, kernels rate and other traits should be selected in different environments. Combined with field resistance, plant types and other traits, excellent maize inbred lines with high yield potential from space mutagenesis offspring were selected. Thus study has obtained some breeding materials useful for further breeding purpose, and provide a reference method as how to use the spaceflight induced materials for for maize breeding. (authors)

  14. Zea mays iRS1563: A Comprehensive Genome-Scale Metabolic Reconstruction of Maize Metabolism

    Science.gov (United States)

    Saha, Rajib; Suthers, Patrick F.; Maranas, Costas D.

    2011-01-01

    The scope and breadth of genome-scale metabolic reconstructions have continued to expand over the last decade. Herein, we introduce a genome-scale model for a plant with direct applications to food and bioenergy production (i.e., maize). Maize annotation is still underway, which introduces significant challenges in the association of metabolic functions to genes. The developed model is designed to meet rigorous standards on gene-protein-reaction (GPR) associations, elementally and charged balanced reactions and a biomass reaction abstracting the relative contribution of all biomass constituents. The metabolic network contains 1,563 genes and 1,825 metabolites involved in 1,985 reactions from primary and secondary maize metabolism. For approximately 42% of the reactions direct literature evidence for the participation of the reaction in maize was found. As many as 445 reactions and 369 metabolites are unique to the maize model compared to the AraGEM model for A. thaliana. 674 metabolites and 893 reactions are present in Zea mays iRS1563 that are not accounted for in maize C4GEM. All reactions are elementally and charged balanced and localized into six different compartments (i.e., cytoplasm, mitochondrion, plastid, peroxisome, vacuole and extracellular). GPR associations are also established based on the functional annotation information and homology prediction accounting for monofunctional, multifunctional and multimeric proteins, isozymes and protein complexes. We describe results from performing flux balance analysis under different physiological conditions, (i.e., photosynthesis, photorespiration and respiration) of a C4 plant and also explore model predictions against experimental observations for two naturally occurring mutants (i.e., bm1 and bm3). The developed model corresponds to the largest and more complete to-date effort at cataloguing metabolism for a plant species. PMID:21755001

  15. Nitrogen transporter and assimilation genes exhibit developmental stage-selective expression in maize (Zea mays L.) associated with distinct cis-acting promoter motifs.

    Science.gov (United States)

    Liseron-Monfils, Christophe; Bi, Yong-Mei; Downs, Gregory S; Wu, Wenqing; Signorelli, Tara; Lu, Guangwen; Chen, Xi; Bondo, Eddie; Zhu, Tong; Lukens, Lewis N; Colasanti, Joseph; Rothstein, Steven J; Raizada, Manish N

    2013-10-01

    Nitrogen is considered the most limiting nutrient for maize (Zea mays L.), but there is limited understanding of the regulation of nitrogen-related genes during maize development. An Affymetrix 82K maize array was used to analyze the expression of ≤ 46 unique nitrogen uptake and assimilation probes in 50 maize tissues from seedling emergence to 31 d after pollination. Four nitrogen-related expression clusters were identified in roots and shoots corresponding to, or overlapping, juvenile, adult, and reproductive phases of development. Quantitative real time PCR data was consistent with the existence of these distinct expression clusters. Promoters corresponding to each cluster were screened for over-represented cis-acting elements. The 8-bp distal motif of the Arabidopsis 43-bp nitrogen response element (NRE) was over-represented in nitrogen-related maize gene promoters. This conserved motif, referred to here as NRE43-d8, was previously shown to be critical for nitrate-activated transcription of nitrate reductase (NIA1) and nitrite reductase (NIR1) by the NIN-LIKE PROTEIN 6 (NLP6) in Arabidopsis. Here, NRE43-d8 was over-represented in the promoters of maize nitrate and ammonium transporter genes, specifically those that showed peak expression during early-stage vegetative development. This result predicts an expansion of the NRE-NLP6 regulon and suggests that it may have a developmental component in maize. We also report leaf expression of putative orthologs of nitrite transporters (NiTR1), a transporter not previously reported in maize. We conclude by discussing how each of the four transcriptional modules may be responsible for the different nitrogen uptake and assimilation requirements of leaves and roots at different stages of maize development.

  16. Pollen-Mediated Gene Flow in Maize: Implications for Isolation Requirements and Coexistence in Mexico, the Center of Origin of Maize.

    Science.gov (United States)

    Baltazar, Baltazar M; Castro Espinoza, Luciano; Espinoza Banda, Armando; de la Fuente Martínez, Juan Manuel; Garzón Tiznado, José Antonio; González García, Juvencio; Gutiérrez, Marco Antonio; Guzmán Rodríguez, José Luis; Heredia Díaz, Oscar; Horak, Michael J; Madueño Martínez, Jesús Ignacio; Schapaugh, Adam W; Stojšin, Duška; Uribe Montes, Hugo Raúl; Zavala García, Francisco

    2015-01-01

    Mexico, the center of origin of maize (Zea mays L.), has taken actions to preserve the identity and diversity of maize landraces and wild relatives. Historically, spatial isolation has been used in seed production to maintain seed purity. Spatial isolation can also be a key component for a strategy to minimize pollen-mediated gene flow in Mexico between transgenic maize and sexually compatible plants of maize conventional hybrids, landraces, and wild relatives. The objective of this research was to generate field maize-to-maize outcrossing data to help guide coexistence discussions in Mexico. In this study, outcrossing rates were determined and modeled from eight locations in six northern states, which represent the most economically important areas for the cultivation of hybrid maize in Mexico. At each site, pollen source plots were planted with a yellow-kernel maize hybrid and surrounded by plots with a white-kernel conventional maize hybrid (pollen recipient) of the same maturity. Outcrossing rates were then quantified by assessing the number of yellow kernels harvested from white-kernel hybrid plots. The highest outcrossing values were observed near the pollen source (12.9% at 1 m distance). The outcrossing levels declined sharply to 4.6, 2.7, 1.4, 1.0, 0.9, 0.5, and 0.5% as the distance from the pollen source increased to 2, 4, 8, 12, 16, 20, and 25 m, respectively. At distances beyond 20 m outcrossing values at all locations were below 1%. These trends are consistent with studies conducted in other world regions. The results suggest that coexistence measures that have been implemented in other geographies, such as spatial isolation, would be successful in Mexico to minimize transgenic maize pollen flow to conventional maize hybrids, landraces and wild relatives.

  17. The EU adventures of 'Herculex' : Report on the EU authorization of the genetically modified maize 1507

    NARCIS (Netherlands)

    Weimer, M.; Pisani, G.

    2014-01-01

    The EU authorization process of the insect-resistant maize 1507, branded by its developer company Pioneer-DuPont as ‘Herculex’, is perhaps the most interesting and emblematic example of the current regulatory crisis of GMO regulation in Europe.1 The case is particularly controversial, because it

  18. Detection of transgenes in local maize varieties of small-scale farmers in eastern cape, South Africa.

    Directory of Open Access Journals (Sweden)

    Marianne Iversen

    Full Text Available Small-scale subsistence farmers in South Africa have been introduced to genetically modified (GM crops for more than a decade. Little is known about i the extent of transgene introgression into locally recycled seed, ii what short and long-term ecological and socioeconomic impacts such mixing of seeds might have, iii how the farmers perceive GM crops, and iv to what degree approval conditions are followed and controlled. This study conducted in the Eastern Cape, South Africa, aims primarily at addressing the first of these issues. We analysed for transgenes in 796 individual maize plants (leaves and 20 seed batches collected in a village where GM insect resistant maize was previously promoted and grown as part of an governmental agricultural development program over a seven year period (2001-2008. Additionally, we surveyed the varieties of maize grown and the farmers' practices of recycling and sharing of seed in the same community (26 farmers were interviewed. Recycling and sharing of seeds were common in the community and may contribute to spread and persistence of transgenes in maize on a local or regional level. By analysing DNA we found that the commonly used transgene promoter p35s occurred in one of the 796 leaf samples (0.0013% and in five of the 20 seed samples (25%. Three of the 20 seed samples (15% included herbicide tolerant maize (NK603 intentionally grown by the farmers from seed bought from local seed retailers or acquired through a currently running agricultural development program. The two remaining positive seed samples (10% included genes for insect resistance (from MON810. In both cases the farmers were unaware of the transgenes present. In conclusion, we demonstrate that transgenes are mixed into seed storages of small-scale farming communities where recycling and sharing of seeds are common, i.e. spread beyond the control of the formal seed system.

  19. The Dent Stage of Maize Kernels Is the Most Conducive for Fumonisin Biosynthesis under Field Conditions ▿

    OpenAIRE

    Picot, Adeline; Barreau, Christian; Pinson-Gadais, Laëtitia; Piraux, François; Caron, Daniel; Lannou, Christian; Richard-Forget, Florence

    2011-01-01

    The fungal pathogen Fusarium verticillioides infects maize ears and produces fumonisins, known for their adverse effects on human and animal health. Basic questions remain unanswered regarding the kernel stage(s) associated with fumonisin biosynthesis and the kernel components involved in fumonisin regulation during F. verticillioides-maize interaction under field conditions. In this 2-year field study, the time course of F. verticillioides growth and fumonisin accumulation in developing maiz...

  20. Molecular diversity of seed-borne Fusarium species associated with maize in India

    Science.gov (United States)

    A total of 62 Fusarium isolates were recovered from 106 maize seeds sampled across 13 states in India, 90% of which were identified as F. verticillioides. Our study included (1) species confirmation through PCR assay using the tef-1a gene, (2) a fumonisin cluster genotype assay using developed multi...

  1. The effect of root temperature on the uptake and metabolism of anions by the root system of Zea mays L. I

    International Nuclear Information System (INIS)

    Holobrada, M.; Mistrik, I.; Kolek, J.

    1980-01-01

    The effect of root temperature upon the uptake of 35 S-sulfate by intact 21 days old maize roots was discussed. The plant roots grown at 20 degC were cooled in steps down to 15 degC or 5 degC. The rate of 35 S uptake was studied both in the whole root system and separately in the individual roots (primary seminal root, seminal adventitious roots and nodal roots). Differences were ascertained at lower uptakes by various root samples from resistant and nonresistant maize cultivars. (author)

  2. Tracing QTLs for Leaf Blast Resistance and Agronomic Performance of Finger Millet (Eleusine coracana (L. Gaertn. Genotypes through Association Mapping and in silico Comparative Genomics Analyses.

    Directory of Open Access Journals (Sweden)

    M Ramakrishnan

    Full Text Available Finger millet is one of the small millets with high nutritive value. This crop is vulnerable to blast disease caused by Pyricularia grisea, which occurs annually during rainy and winter seasons. Leaf blast occurs at early crop stage and is highly damaging. Mapping of resistance genes and other quantitative trait loci (QTLs for agronomic performance can be of great use for improving finger millet genotypes. Evaluation of one hundred and twenty-eight finger millet genotypes in natural field conditions revealed that leaf blast caused severe setback on agronomic performance for susceptible genotypes, most significant traits being plant height and root length. Plant height was reduced under disease severity while root length was increased. Among the genotypes, IE4795 showed superior response in terms of both disease resistance and better agronomic performance. A total of seven unambiguous QTLs were found to be associated with various agronomic traits including leaf blast resistance by association mapping analysis. The markers, UGEP101 and UGEP95, were strongly associated with blast resistance. UGEP98 was associated with tiller number and UGEP9 was associated with root length and seed yield. Cross species validation of markers revealed that 12 candidate genes were associated with 8 QTLs in the genomes of grass species such as rice, foxtail millet, maize, Brachypodium stacei, B. distachyon, Panicum hallii and switchgrass. Several candidate genes were found proximal to orthologous sequences of the identified QTLs such as 1,4-β-glucanase for leaf blast resistance, cytokinin dehydrogenase (CKX for tiller production, calmodulin (CaM binding protein for seed yield and pectin methylesterase inhibitor (PMEI for root growth and development. Most of these QTLs and their putatively associated candidate genes are reported for first time in finger millet. On validation, these novel QTLs may be utilized in future for marker assisted breeding for the development of

  3. Tracing QTLs for Leaf Blast Resistance and Agronomic Performance of Finger Millet (Eleusine coracana (L.) Gaertn.) Genotypes through Association Mapping and in silico Comparative Genomics Analyses.

    Science.gov (United States)

    Ramakrishnan, M; Antony Ceasar, S; Duraipandiyan, V; Vinod, K K; Kalpana, Krishnan; Al-Dhabi, N A; Ignacimuthu, S

    2016-01-01

    Finger millet is one of the small millets with high nutritive value. This crop is vulnerable to blast disease caused by Pyricularia grisea, which occurs annually during rainy and winter seasons. Leaf blast occurs at early crop stage and is highly damaging. Mapping of resistance genes and other quantitative trait loci (QTLs) for agronomic performance can be of great use for improving finger millet genotypes. Evaluation of one hundred and twenty-eight finger millet genotypes in natural field conditions revealed that leaf blast caused severe setback on agronomic performance for susceptible genotypes, most significant traits being plant height and root length. Plant height was reduced under disease severity while root length was increased. Among the genotypes, IE4795 showed superior response in terms of both disease resistance and better agronomic performance. A total of seven unambiguous QTLs were found to be associated with various agronomic traits including leaf blast resistance by association mapping analysis. The markers, UGEP101 and UGEP95, were strongly associated with blast resistance. UGEP98 was associated with tiller number and UGEP9 was associated with root length and seed yield. Cross species validation of markers revealed that 12 candidate genes were associated with 8 QTLs in the genomes of grass species such as rice, foxtail millet, maize, Brachypodium stacei, B. distachyon, Panicum hallii and switchgrass. Several candidate genes were found proximal to orthologous sequences of the identified QTLs such as 1,4-β-glucanase for leaf blast resistance, cytokinin dehydrogenase (CKX) for tiller production, calmodulin (CaM) binding protein for seed yield and pectin methylesterase inhibitor (PMEI) for root growth and development. Most of these QTLs and their putatively associated candidate genes are reported for first time in finger millet. On validation, these novel QTLs may be utilized in future for marker assisted breeding for the development of fungal

  4. Isolation of 14C labelled amino acids by biosynthesis in maize plants (Zea mais L.)

    International Nuclear Information System (INIS)

    Carreras, N.; Mazon, M.P.

    1983-01-01

    A method of obtaining 14 C labelled amino acids by biosynthesis in maize plants which had assimilated 14CO 2 , has been assayed. The plants were labelled for 60 minutes with 14 C O2 produced from Ba 14 C O3 (specific activity of 148 KBq/μmol). An extract of the soluble compounds was obtained with 80% ethanol and the amino acids were separated from the rest of the soluble compounds by ion exchange chromatography on column of Dowex 50-X8 resin. Finally, seventeen amino acids were isolated and identified from the purified extract. The acid amino acids were separated in anionic column (Dowex 1-X8) and the neutral and basic amino acids in cationic column (Dowex 50-X4). (Author) 56 refs

  5. Isolation of carbon 14 labelled amino acids by biosynthesis in maize plants (zea mais L.)

    International Nuclear Information System (INIS)

    Carreras, N.; Mazon, M.P.

    1983-01-01

    A method of obtaining 14 C labelled amino acids by biosynthesis in maize plants which had assimilated 14 CO 2 , has been assayed. The plants were labelled for 60 minutes with 14 CO 2 produced from Ba 14 CO 3 (specific activity of 148 KBq/μmol). An extract of the soluble compounds was obtained with 80% ethanol and the amino acids were separated from the rest of the soluble compounds by ion exchange chromatography on column of Dowex 50-X8 resin. Finally, seventeen amino acids were isolated and identified from the purified extract. The acid amino acids were separated in anionic column (Dowex 1-X8) and the neutral and basic amino acids in cationic columns (Dowex 50-X4). (author)

  6. Importance of amylases for physiological quality in maize seeds

    Directory of Open Access Journals (Sweden)

    Camila Aparecida Lopes

    2017-09-01

    Full Text Available Seed quality is the result of the sum of genetic, physical, physiological and sanitary attributes that affect seed ability to perform vital functions related to germination, vigor, and longevity. The expression of genes associated with physiological quality can be assessed by means of germination and vigor analyses, as well as by transcript and protein analyses. The objective in this work was to review the relevance of amylase group enzymes to the physiological quality of maize seeds. Within this group, α-amylase (1,4-α-D-glucan glucanohydrolase E.C 3.2.1.1 plays an important role in starch hydrolysis, and is responsible for 90% of the amylolytic activity in maize seeds. It is responsible for starch conversion into sugars (e.g., destrin, which is used for embryo growth. β-amylase (1,4-α-D-glucan maltohydrolase E.C 3.2.1.2 catalyzes the release of maltose and dextrins from the non-reducing ends of starch. Research has shown that amylase enzymes are directly linked to physiological quality of maize seeds. Alpha- and beta-amylases are mainly involved in the germination process and seed heterosis, and can also be used as molecular markers associated with seed tolerance for drying.

  7. Lack of Contribution of Multidrug Resistance-associated Protein and Organic Anion-transporting Polypeptide to Pharmacokinetics of Regorafenib, a Novel Multi-Kinase Inhibitor, in Rats.

    Science.gov (United States)

    Hotta, Kazuo; Ueyama, Jun; Tatsumi, Yasuaki; Tsukiyama, Ikuto; Sugiura, Yuka; Saito, Hiroko; Matsuura, Katsuhiko; Hasegawa, Takaaki

    2015-09-01

    We investigated whether hepatic multidrug resistance-associated protein 2 (ABCC2) is involved in the hepatobiliary excretion of regorafenib, a novel multi-kinase inhibitor, using Sprague-Dawley (SD) rats and Eisai hyperbilirubinemic rats (EHBR) lacking the efflux transporter ABCC2. The involvement of organic anion-transporting polypeptide 1 (OATP1; OATP in humans) and OATP2 in the hepatic uptake of regorafenib and their protein levels in the liver were also investigated in the two rat groups. When regorafenib (5 mg/kg) was administered intravenously, the plasma concentrations of regorafenib were higher in EHBR than those in SD rats. However, the slope of the plasma concentration-time curves was the same for the two groups. Although the apparent biliary clearance of regorafenib in EHBR was lower than that of SD rats, no significant difference in the biliary excretion rate was observed between them, suggesting that regorafenib is not a substrate for ABCC2 and is not excreted into bile by ABCC2. It was also found that the contribution of biliary excretion to the systemic elimination of regorafenib is small. The protein-binding profiles of regorafenib were found to be linear in both rat groups. The binding potency, which was very high in both rat groups (>99.5%), was significantly higher in EHBR than that in SD rats. No significant differences in the plasma concentrations of unbound regorafenib were observed between the two rat groups, suggesting that the differences observed in the pharmacokinetic behaviors of regorafenib between the two rat groups were due to differences in protein-binding. When the protein levels of hepatic OATP1 and OATP2 were measured by immunoblot analysis, the expression of both transporters in EHBR was less than 40% of that in SD rats. The present results suggest that regorafenib is not a substrate for OATP1 and OATP2. These findings suggest the possibility that ABCC2-mediated hepatobiliary excretion and OATP1/OATP2-mediated hepatic uptake do

  8. SNP frequency, haplotype structure and linkage disequilibrium in elite maize inbred lines

    Directory of Open Access Journals (Sweden)

    Smith Oscar

    2002-10-01

    Full Text Available Abstract Background Recent studies of ancestral maize populations indicate that linkage disequilibrium tends to dissipate rapidly, sometimes within 100 bp. We set out to examine the linkage disequilibrium and diversity in maize elite inbred lines, which have been subject to population bottlenecks and intense selection by breeders. Such population events are expected to increase the amount of linkage disequilibrium, but reduce diversity. The results of this study will inform the design of genetic association studies. Results We examined the frequency and distribution of DNA polymorphisms at 18 maize genes in 36 maize inbreds, chosen to represent most of the genetic diversity in U.S. elite maize breeding pool. The frequency of nucleotide changes is high, on average one polymorphism per 31 bp in non-coding regions and 1 polymorphism per 124 bp in coding regions. Insertions and deletions are frequent in non-coding regions (1 per 85 bp, but rare in coding regions. A small number (2–8 of distinct and highly diverse haplotypes can be distinguished at all loci examined. Within genes, SNP loci comprising the haplotypes are in linkage disequilibrium with each other. Conclusions No decline of linkage disequilibrium within a few hundred base pairs was found in the elite maize germplasm. This finding, as well as the small number of haplotypes, relative to neutral expectation, is consistent with the effects of breeding-induced bottlenecks and selection on the elite germplasm pool. The genetic distance between haplotypes is large, indicative of an ancient gene pool and of possible interspecific hybridization events in maize ancestry.

  9. Baseline sensitivity of maize borers in India to the Bacillus thuringiensis insecticidal proteins Cry1A.105 and Cry2Ab2.

    Science.gov (United States)

    Jalali, Sushil K; Yadavalli, Lalitha; Ojha, Rakshit; Kumar, Pradyumn; Sulaikhabeevi, Suby B; Sharma, Reema; Nair, Rupa; Kadanur, Ravi C; Kamath, Subray P; Komarlingam, Mohan S

    2015-08-01

    Among the major pests of maize in India are two stem borers, Chilo partellus (Swinhoe) and Sesamia inferens (Walker), and an earworm, Helicoverpa armigera (Hübner). As a pest control strategy, transgenic Bacillus thuringiensis (Bt) maize hybrids are undergoing regulatory trials in India. We have determined the sensitivity of the target lepidopterans to the insecticidal Bt proteins expressed in Bt maize, as this determines product efficacy and the resistance management strategy to be adopted. Maize hybrids with event MON89034 express two insecticidal Bt proteins, Cry1A.105 and Cry2Ab2. Sensitivity profiles of 53 populations of C. partellus, 21 populations of S. inferens and 21 populations of H. armigera, collected between 2008 and 2013 from maize-growing areas in India, to Cry1A.105 and Cry2Ab2 proteins were generated through dose-response assays. Cry1A.105 protein was the most effective to neonates of C. partellus (mean MIC90 range 0.30-1.0 µg mL(-1) ) and H. armigera (mean MIC90 range 0.71-8.22 µg mL(-1) ), whereas Cry2Ab2 (mean MIC90 range 0.65-1.70 µg mL(-1) ) was the most effective to S. inferens. Populations of C. partellus, S. inferens and H. armigera were susceptible to the Bt proteins Cry1A.105 and Cry2Ab2. The Bt sensitivity data will serve as precommercialisation benchmarks for resistance monitoring purposes. © 2014 Society of Chemical Industry.

  10. Maize, tropical (Zea mays L.).

    Science.gov (United States)

    Assem, Shireen K

    2015-01-01

    Maize (Zea mays L.) is the third most important food crop globally after wheat and rice. In sub-Saharan Africa, tropical maize has traditionally been the main staple of the diet; 95 % of the maize grown is consumed directly as human food and as an important source of income for the resource-poor rural population. The biotechnological approach to engineer biotic and abiotic traits implies the availability of an efficient plant transformation method. The production of genetically transformed plants depends both on the ability to integrate foreign genes into target cells and the efficiency with which plants are regenerated. Maize transformation and regeneration through immature embryo culture is the most efficient system to regenerate normal transgenic plants. However, this system is highly genotype dependent. Genotypes adapted to tropic areas are difficult to regenerate. Therefore, transformation methods used with model genotypes adapted to temperate areas are not necessarily efficient with tropical lines. Agrobacterium-mediated transformation is the method of choice since it has been first achieved in 1996. In this report, we describe a transformation method used successfully with several tropical maize lines. All the steps of transformation and regeneration are described in details. This protocol can be used with a wide variety of tropical lines. However, some modifications may be needed with recalcitrant lines.

  11. Effect of Bambara nut and cowpea intercropped with maize at different times on nutritive quality of maize for ruminant feeding

    Directory of Open Access Journals (Sweden)

    Olanite, J. A.

    2017-06-01

    Full Text Available Effects of Bambara nut and cowpea planted with maize at different times on nutritive quality of maize forage were investigated. The study was laid out in a Completely Randomized Design and the treatments were combination of crop types (Bambara nut-maize (MB and Cowpea-maize (MC and planting times of legumes (2 wks before planting maize, 2WBPM and 2 wks after planting maize, 2WAPM, and sole maize (as control. An experimental field measuring 19 m � 11 m was divided into 3 replicates; each replicate was sub-divided into 5 plots of dimension 3 m2 each, with 1 m and 2 m inter-plots and inter-blocks spacing respectively. Maize forage samples were harvested on each plot at 10 wks after planting, oven-dried, milled and analyzed to evaluate the chemical composition, mineral composition, in vitro gas production and post-incubation characteristics. Results revealed significant differences (P<0.05 among treatments with the highest (95.00% and least DM (92.12% values were recorded for MB 2WBPM and MC 2WAPM, respectively. CP values ranged from 10.36% in MB 2WBPM to 15.67% in MC 2WBPM but not significantly different from 14.19 % recorded for sole maize. Ash ranged from 7.00% in MB 2WAPM to 10.00% in sole maize. MC 2WBPM and sole maize had the highest (50.63% and least (38.40% in ADF content (P<0.05. ADL value (7.25% observed in MB 2WBPM was the highest, compared to the least (5.00% in sole maize. Sole maize recorded the least (40.40% and highest (25.91% cellulose and hemicellulose contents, respectively while MC 2WAPM had the highest (50.88% and lowest (15.80% values for cellulose and hemicellulose, respectively. Ca content (4.55g/kg of MB 2WAPM was lower than the other treatments. P content ranged from 3.54 g/kg in MB 2WAPM to 12.02 g/kg in MC 2WAPM. Gas production rates only varied (P<0.05 at the 3rd, 6th, 24th and 48th hours of incubation. MB 2WBPM yielded highest values of short chain fatty acids (0.09 �mol and metabolizable energy (3.08 MJ/kg while MB

  12. Short communication: QTL mapping for ear tip-barrenness in maize

    Energy Technology Data Exchange (ETDEWEB)

    Ding, J.; Ma, J.; Chen, J.; Ai, T.; Li, Z.; Tian, Z.; Wu, S.; Chen, W.; Wu, J.

    2016-11-01

    Barren tip on corn ear is an important agronomic trait in maize, which is highly associated with grain yield. Understanding the genetic basis of tip-barrenness may help to reduce the ear tip-barrenness in breeding programs. In this study, ear tip-barrenness was evaluated in two environments in a F2:3 population, and it showed significant genotypic variation for ear tip-barrenness in both environments. Using mixed-model composite interval mapping method, three additive effects quantitative trait loci (QTL) for ear tip-barrenness were mapped on chromosomes 2, 3 and 6, respectively. They explained 16.6% of the phenotypic variation, and no significant QTL × Environment interactions and digenic interactions were detected. The results indicated that additive effect was the main genetic basis for ear tip-barrenness in maize. This is the first report of QTL mapped for ear tip-barrenness in maize. (Author)

  13. Characterization of Indian and exotic quality protein maize (QPM ...

    African Journals Online (AJOL)

    Polymorphism analysis and genetic diversity of normal maize and quality protein maize (QPM) inbreds among locally well adapted germplasm is a prerequisite for hybrid maize breeding program. The diversity analyses of 48 maize accessions including Indian and exotic germplasm using 75 simple sequence repeat (SSR) ...

  14. Transfer of 65Zn in maize -mycorrhizal systems: a potential mechanism to alleviate Zn deficiency in maize

    International Nuclear Information System (INIS)

    Subramanian, K.S.; Tenshia, Virgin

    2017-01-01

    Mycorrhizas are root associated fungi and obligate symbionts known to improve the nutritional status of the host plant as a direct consequence of transfer of slowly diffusing nutrients such as zinc. The Zn use efficiency by crops hardly exceeds 2-5 per cent and major portion of the Zn gets accumulated in soil in various pools which are not available to plants. Further, mycorrhizal symbiosis alters the chemical and biochemical properties of rhizosphere that affect the isotopic parameters such as A value, E value and L value. These parameters were measured for both mycorrhizal and non-mycorrhizal maize plants. A pot culture experiment was conducted to determine the availability of Zn using isotopic dilution techniques. Maize plants were grown in pots inoculated with (M+) or without (M-) mycorrhizal fungus Glomus intraradices. Tagged 65 ZnSO 4 was applied to soil at the time of sowing

  15. Screening of different insecticides against maize shoot fly atherigona soccata (Rond.) and maize borer. chilo partellus (swinh.)

    International Nuclear Information System (INIS)

    Shahid, M.A.; Rana, Z.A.; Haq, I.; Tariq, H.

    2010-01-01

    Field studies were carried out in the research area of the Ayub Agricultural Research Institute, Faisalabad to determine the most effective maize seed treatment against maize shoot fly Atherigona soccata (Rond.) and insecticide against maize borer Chilo partellus (Swinh.) Trials were conducted following RCBD and replicated three times during 2005-2006. Two seed treatments Confider (imidacloprid) 70 WS and pensidor 72% WP (5 and 7 mg/kg seed) along with Confider (imidaclorid) 200 SC at the rate 40 ml/acre in the trial against maize shoot fly whereas, flubendiamide 48%, emamection 1.9 EC, spinosad 240 EC. carbofuran 3 G, indoxacarb 150 SC, alphacypermethrine 20 EC, monomehypo 5 G, bifenthrin 10 EC, cartap 4G, cyhalothrine 2.5 EC, cypermethrin 10 EC at the rate 20 ml, 150 ml, 40 ml, 8 kg, 150 ml, 200 ml, 5 kg, 150 ml, 6 kg. 250 ml and 300 ml per acre against maize borer were treated keeping one plo ast untreated check. Treatments were repeated as borer infestation reached above 5% level. All the seed treatments showed significant control of maize shoot fly in spite of dose 5 or 7 mg/kg seed along with foliar spray of confider 200 SC. The insecticides viz. flubendiamide 48% SC. emamectin 1.9 EC, spinosad 240 EC and carbofuran 3 G. indoxacarb 150 SC. alpha cypermethrin 20 EC, not only responded highest yield 5765, 5294, 5289, 5215, 5168 and 5025 kg/ha respectively but also manage the maize borer below ETL. (author)

  16. A(maize)ing attraction: gravid Anopheles arabiensis are attracted and oviposit in response to maize pollen odours.

    Science.gov (United States)

    Wondwosen, Betelehem; Hill, Sharon R; Birgersson, Göran; Seyoum, Emiru; Tekie, Habte; Ignell, Rickard

    2017-01-23

    Maize cultivation contributes to the prevalence of malaria mosquitoes and exacerbates malaria transmission in sub-Saharan Africa. The pollen from maize serves as an important larval food source for Anopheles mosquitoes, and females that are able to detect breeding sites where maize pollen is abundant may provide their offspring with selective advantages. Anopheles mosquitoes are hypothesized to locate, discriminate among, and select such sites using olfactory cues, and that synthetic volatile blends can mimic these olfactory-guided behaviours. Two-port olfactometer and two-choice oviposition assays were used to assess the attraction and oviposition preference of gravid Anopheles arabiensis to the headspace of the pollen from two maize cultivars (BH-660 and ZM-521). Bioactive compounds were identified using combined gas chromatography and electroantennographic detection from the headspace of the cultivar found to be most attractive (BH-660). Synthetic blends of the volatile compounds were then assessed for attraction and oviposition preference of gravid An. arabiensis, as above. Here the collected headspace volatiles from the pollen of two maize cultivars was shown to differentially attract and stimulate oviposition in gravid An. arabiensis. Furthermore, a five-component synthetic maize pollen odour blend was identified, which elicited the full oviposition behavioural repertoire of the gravid mosquitoes. The cues identified from maize pollen provide important substrates for the development of novel control measures that modulate gravid female behaviour. Such measures are irrespective of indoor or outdoor feeding and resting patterns, thus providing a much-needed addition to the arsenal of tools that currently target indoor biting mosquitoes.

  17. Mixing of maize and wheat genomic DNA by somatic hybridization in regenerated sterile maize plants.

    Science.gov (United States)

    Szarka, B.; Göntér, I.; Molnár-Láng, M.; Mórocz, S.; Dudits, D.

    2002-07-01

    Intergeneric somatic hybridization was performed between albino maize ( Zea mays L.) protoplasts and mesophyll protoplasts of wheat ( Triticum aestivum L.) by polyethylene glycol (PEG) treatments. None of the parental protoplasts were able to produce green plants without fusion. The maize cells regenerated only rudimentary albino plantlets of limited viability, and the wheat mesophyll protoplasts were unable to divide. PEG-mediated fusion treatments resulted in hybrid cells with mixed cytoplasm. Six months after fusion green embryogenic calli were selected as putative hybrids. The first-regenerates were discovered as aborted embryos. Regeneration of intact, green, maize-like plants needed 6 months of further subcultures on hormone-free medium. These plants were sterile, although had both male and female flowers. The cytological analysis of cells from callus tissues and root tips revealed 56 chromosomes, but intact wheat chromosomes were not observed. Using total DNA from hybrid plants, three RAPD primer combinations produced bands resembling the wheat profile. Genomic in situ hybridization (GISH) using total wheat DNA as a probe revealed the presence of wheat DNA islands in the maize chromosomal background. The increased viability and the restored green color were the most-significant new traits as compared to the original maize parent. Other intermediate morphological traits of plants with hybrid origin were not found.

  18. The many ways of making anionic clays

    Indian Academy of Sciences (India)

    Together with hydrotalcite-like layered double hydroxides, bivalent and trivalent metal hydroxides and their hydroxy salts are actually anionic clays consisting of positively charged hydroxide layers with anions intercalated in the interlayer region. The anionic clays exhibit anion sorption, anion diffusion and exchange ...

  19. Isolation of 14{sub C} labelled amino acids by biosynthesis in maize plants (Zea mais L.); Obtencin de aminoacidos marcados con 14{sub C} por biosintesis en plantulas de maiz (Zea mais L)

    Energy Technology Data Exchange (ETDEWEB)

    Carreras, N; Mazon, M P

    1983-07-01

    A method of obtaining 14{sub C} labelled amino acids by biosynthesis in maize plants which had assimilated 14CO{sub 2}, has been assayed. The plants were labelled for 60 minutes with 14{sub C}O2 produced from Ba 14{sub C}O3 (specific activity of 148 KBq/{mu}mol). An extract of the soluble compounds was obtained with 80% ethanol and the amino acids were separated from the rest of the soluble compounds by ion exchange chromatography on column of Dowex 50-X8 resin. Finally, seventeen amino acids were isolated and identified from the purified extract. The acid amino acids were separated in anionic column (Dowex 1-X8) and the neutral and basic amino acids in cationic column (Dowex 50-X4). (Author) 56 refs.

  20. Associations of planting date, drought stress, and insects with Fusarium ear rot and fumonisin B1 contamination in California maize.

    Science.gov (United States)

    Parsons, M W; Munkvold, G P

    2010-05-01

    Fusarium ear rot, caused by Fusarium verticillioides, is one of the most common diseases of maize, causing yield and quality reductions and contamination of grain by fumonisins and other mycotoxins. Drought stress and various insects have been implicated as factors affecting disease severity. Field studies were conducted to evaluate the interactions and relative influences of drought stress, insect infestation, and planting date upon Fusarium ear rot severity and fumonisin B1 contamination. Three hybrids varying in partial resistance to Fusarium ear rot were sown on three planting dates and subjected to four irrigation regimes to induce differing levels of drought stress. A foliar-spray insecticide treatment was imposed to induce differing levels of insect injury. Populations of thrips (Frankliniella spp.), damage by corn earworm (Helicoverpa zeae), Fusarium ear rot symptoms, and fumonisin B1 levels were assessed. There were significant effects of hybrid, planting date, insecticide treatment, and drought stress on Fusarium ear rot symptoms and fumonisin B1 contamination, and these factors also had significant interacting effects. The most influential factors were hybrid and insecticide treatment, but their effects were influenced by planting date and drought stress. The more resistant hybrids and the insecticide-treated plots consistently had lower Fusarium ear rot severity and fumonisin B1 contamination. Later planting dates typically had higher thrips populations, more Fusarium ear rot, and higher levels of fumonisin B1. Insect activity was significantly correlated with disease severity and fumonisin contamination, and the correlations were strongest for thrips. The results of this study confirm the influence of thrips on Fusarium ear rot severity in California, USA, and also establish a strong association between thrips and fumonisin B1 levels.

  1. Applying CSM-CERES-Maize to define a sowing window for irrigated maize crop - The Riacho´s Farm case study

    Directory of Open Access Journals (Sweden)

    Denise Freitas Silva

    2011-08-01

    Full Text Available Irrigation use constitutes an alternative to improve maize production in Central Minas Gerais State, Brazil. However, even under adequate water supply conditions, other environmental factors may influence maize crop growth and development and may, ultimately, affect grain yield. This study aimed to establish a sowing window for irrigated maize crop, based on simulation results obtained with the decision support model CSM-CERES-Maize. Simulations were made for crop management conditions of Riacho´s Farm, located in Matozinhos, Minas Gerais State, Brazil. It was employed the model´s seasonal tool, along with a data set containing 46 years of weather data records, to simulate maize yield for weekly sowing scenarios, starting on August 1st and ending on July 24th of each year. One defined an irrigated maize sowing window, taking into account the yield break risk that a farmer would be willing to take. The model proved to be an interesting tool to assist in decision making, regarding crop and irrigation management, for an irrigated maize production system. Assuming a 10% yield break in the expected average maximum maize yield, it was defined as sowing window, the period from January 23rd to March 6th, with February 20th as the best sowing date. Other sowing windows may be established according to the risk that the farmer would be willing to take.

  2. Status and prospects of maize research in Nepal

    Directory of Open Access Journals (Sweden)

    Govind KC

    2015-12-01

    Full Text Available Food and nutritional securities are the major threats coupled with declining factor productivity and climate change effects in Nepal. Maize being the principal food crops of the majority of the hill people and source of animal feed for ever growing livestock industries in Terai of Nepal. Despite the many efforts made to increase the maize productivity in the country, the results are not much encouraging. Many of the maize based technologies developed and recommended for the farmers to date are not fully adopted. Therefore, problem is either on technology development or on dissemination or on both. Considering the above facts, some of the innovative and modern approaches of plant breeding and crop management technologies to increase the maize yield need to be developed and disseminated. There is a need for location-specific maize production technologies, especially for lowland winter maize, marginal upland maize production system, and resource poor farmers. Research efforts can be targeted to address both yield potential and on-farm yields by reducing the impacts of abiotic and biotic constraints. Therefore, in order to streamline the future direction of maize research in Nepal, an attempt has been made in this article to highlight the present status and future prospects with few key pathways.

  3. Prevalence of community-associated methicillin–resistant ...

    African Journals Online (AJOL)

    Background: Community-associated methicillin-resistant Staphylococcus aureus is increasingly reported. This study investigated its prevalence in urine of healthy women and resistance pattern to other antibiotics. Methods: Urine samples collected from healthy women volunteers in Federal Capital Territory were cultured ...

  4. Control of Fusarium verticillioides, cause of ear rot of maize, by Pseudomonas fluorescens.

    Science.gov (United States)

    Nayaka, Siddaiah Chandra; Shankar, Arakere C Udaya; Reddy, Munagala S; Niranjana, Siddapura R; Prakash, Harishchandra S; Shetty, Hunthrike S; Mortensen, Carmen N

    2009-07-01

    Maize is one of the staple food crops grown in India. Fusarium verticillioides (Sacc.) Nirenberg is the most important fungal pathogen of maize, associated with diseases such as ear rot and kernel rot. Apart from the disease, it is capable of producing fumonisins, which have elicited considerable attention over the past decade owing to their association with animal disease syndromes. Hence, the present study was conducted to evaluate ecofriendly approaches by using a maize rhizosphere isolate of Pseudomonas fluorescens (Trev.) Mig. and its formulation to control ear rot disease and fumonisin accumulation, and also to study the capacity to promote growth and yield of maize. In vitro assays were conducted to test the efficacy of P. fluorescens as a seed treatment on seed germination, seedling vigour and also the incidence of F. verticillioides in different maize cultivars. The field trials included both seed treatment and foliar spray. For all the experiments, P. fluorescens was formulated using corn starch, wheat bran and talc powder. In each case there were three different treatments of P. fluorescens, a non-treated control and chemical control. Pure culture and the formulations, in comparison with the control, increased plant growth and vigour as measured by seed germination, seedling vigour, plant height, 1000 seed weight and yield. P. fluorescens pure culture used as seed treatment and as spray treatment enhanced the growth parameters and reduced the incidence of F. verticillioides and the level of fumonisins to a maximum extent compared with the other treatments. The study demonstrates the potential role of P. fluorescens and its formulations in ear rot disease management. The biocontrol potential of this isolate is more suited for fumonisin reduction in maize kernels intended for human and animal feed. (c) 2009 Society of Chemical Industry.

  5. Effect of chemical retention on anionic species diffusion in compacted clays

    International Nuclear Information System (INIS)

    Bazer-Bachi, Frederic

    2005-01-01

    Anionic radioisotopes are of particular importance within the framework of the calculated health risk associated with high-level and long-lived intermediate-level underground radioactive waste disposal. Therefore, the objective of this work is the construction of a transport model coupled with chemistry in order to quantify the behaviour of anionic solutes in the Callovo-Oxfordian (CO_x) argillite, the argillaceous host rock of the ANDRA Meuse/Haute-Marne underground laboratory. An experimental methodology was defined to characterize this migration, several experimental methods being implemented: batch experiments, laboratory columns and through-diffusion cells. The study of the diffusion of the non-sorbing anionic tracer "3"6Cl"- highlighted the fact that, due to anionic exclusion, anions only had access to a part of the porosity. The retention of "3"5SO_4"2"- and "1"2"5I- on CO_x argillite was then characterized, quantified by batch experiments and confirmed by other experimental methods. Nevertheless, their migration was less retarded than expected by a model based on batch experiments and on "3"6Cl"- diffusive data. This difference was explained by anion exclusion which reduced sorption site accessibility. Thus, the intensity of this phenomenon has to be considered to model anion migration in compacted clays. (author) [fr

  6. The mechanisms of root exudates of maize in improvement of iron nutrition of peanut in peanut/maize intercropping system by 14C tracer technique

    International Nuclear Information System (INIS)

    Zuo Yuanmei; Chen Qing; Zhang Fusuo

    2004-01-01

    The related mechanisms of root exudates of maize in improvement iron nutrition of peanut intercropped with maize was investigated by 14 C tracer technique. Neighboring roots between maize and peanut were separated by a 30 μm nylon net, the iron nutrition of peanut was also improved just like normal intercropping of maize and peanut. The results proved that root exudates of maize played an important role in improvement iron nutrition of peanut. The photosynthesis carbohydrate of maize could exuded into the rhizosphere of peanut and transfer into shoot and root of peanut in intercropping system. Root exudates of maize could increased efficiency of iron in soil and improved iron utilization of peanut

  7. Identification of genomic associations for adult plant resistance in the background of popular South Asian wheat cultivar, PBW343

    Directory of Open Access Journals (Sweden)

    Huihui Li

    2016-11-01

    Full Text Available Rusts, a fungal disease as old as its host plant wheat, an enemy as old as wheat, has caused havoc for over 8,000 years. As the rust pathogens can evolve into new virulent races which quickly defeat to qualitative or vertical the resistance that primarily rely on race specificity over time, adult plant resistance (APR has often been found to be race non-specific and hence is considered have been proven to be a more to be a more reliable and durable strategy to combat this malady. Over decades sets of donor lines have been identified at International Maize and Wheat Improvement Center (CIMMYT representing a wide range of APR sources in wheat. In this study, using nine donors and a common parent ‘PBW343’, a popular Green Revolution variety at CIMMYT, the nested association mapping (NAM population of 1122 lines was constructed to understand the APR genetics underlying these founder lines. Thirty-four QTL were associated with APR to rusts, and 20 of 34 QTL had pleiotropic effects on SR, YR and LR resistance. Three chromosomal regions, associated with known APR genes (Sr58/Yr29/Lr46, Sr2/Yr30/Lr27, and Sr57/Yr18/Lr34, were also identified, 13 previously reported QTL regions were validated. Of the 18 QTL first detected in this study, 7 were pleiotropic QTL, distributing on chromosomes 3A, 3B, 6B, 3D, and 6D. The present investigation revealed the genetic relationship of historical APR donor lines, the novel knowledge on APR, as well as the new analytical methodologies to facilitate the applications of NAM design in crop genetics. Results shown in this study will aid the parental selection for hybridization in wheat breeding, and envision the future rust management breeding for addressing potential threat to wheat production and food security.

  8. Rainfall and crop modeling-based water stress assessment for rainfed maize cultivation in peninsular India

    Science.gov (United States)

    Manivasagam, V. S.; Nagarajan, R.

    2018-04-01

    Water stress due to uneven rainfall distribution causes a significant impact on the agricultural production of monsoon-dependent peninsular India. In the present study, water stress assessment for rainfed maize crop is carried out for kharif (June-October) and rabi (October-February) cropping seasons which coincide with two major Indian monsoons. Rainfall analysis (1976-2010) shows that the kharif season receives sufficient weekly rainfall (28 ± 32 mm) during 26th-39th standard meteorological weeks (SMWs) from southwest monsoon, whereas the rabi season experiences a major portion of its weekly rainfall due to northeast monsoon between the 42nd and 51st SMW (31 ± 42 mm). The later weeks experience minimal rainfall (5.5 ± 15 mm) and thus expose the late sown maize crops to a severe water stress during its maturity stage. Wet and dry spell analyses reveal a substantial increase in the rainfall intensity over the last few decades. However, the distribution of rainfall shows a striking decrease in the number of wet spells, with prolonged dry spells in both seasons. Weekly rainfall classification shows that the flowering and maturity stages of kharif maize (33rd-39th SMWs) can suffer around 30-40% of the total water stress. In the case of rabi maize, the analysis reveals that a shift in the sowing time from the existing 42nd SMW (16-22 October) to the 40th SMW (1-7 October) can avoid terminal water stress. Further, AquaCrop modeling results show that one or two minimal irrigations during the flowering and maturity stages (33rd-39th SMWs) of kharif maize positively avoid the mild water stress exposure. Similarly, rabi maize requires an additional two or three lifesaving irrigations during its flowering and maturity stages (48th-53rd SMWs) to improve productivity. Effective crop planning with appropriate sowing time, short duration crop, and high yielding drought-resistant varieties will allow for better utilization of the monsoon rain, thus reducing water stress with

  9. Supramolecular Chemistry of Environmentally Relevant Anions

    International Nuclear Information System (INIS)

    Bowman-James, Kristin; Moyer, B.A.; Sessler, Jonathan L.

    2003-01-01

    The goal of this project is the development of highly selective extractants for anions targeting important and timely problems of critical interest to the EMSP mission. In particular, sulfate poses a special problem in cleaning up the Hanford waste tanks in that it interferes with vitrification, but available technologies for sulfate removal are limited. The basic chemical aspects of anion receptor design of functional pH independent systems as well as design of separations strategies for selective and efficient removal of targeted anions have been probed. Key findings include: (1) some of the first synthetic sulfate-selective anion-binding agents; (2) simple, structure-based methods for modifying the intrinsic anion selectivity of a given class of anion receptors; and (3) the first system capable of extracting sulfate from acidic, nitrate-containing aqueous media. Receptor design, structural influences on anion binding affinities, and findings from liquid-liquid extraction studies will be discussed

  10. Selection for drought tolerance in two tropical maize populations ...

    African Journals Online (AJOL)

    Drought is a major factor limiting maize (Zea mays L.) yield in much of the world. The need to breed maize cultivars with improved drought tolerance is apparent. This study compared two maize populations, ZM601 and ZM607 for drought tolerance during flowering, the most drought-vulnerable period for the maize plant.

  11. Effects of maize planting patterns on the performance of cassava ...

    African Journals Online (AJOL)

    sola

    The design was a split-plot arrangement, laid out in a randomized ... significant differences (P<0.05) between the treatments in the growth and yield parameters of maize. The mean effects of companion crops on maize leaf area were 0.61, 0.60, 0.60 and 0.52 m2/plant for sole maize, maize / melon, maize / cassava and.

  12. Intraguild interactions and behavior of Spodoptera frugiperda and Helicoverpa spp. on maize.

    Science.gov (United States)

    Bentivenha, José Pf; Montezano, Débora G; Hunt, Thomas E; Baldin, Edson Ll; Peterson, Julie A; Victor, Vinícius S; Pannuti, Luiz Er; Vélez, Ana M; Paula-Moraes, Silvana V

    2017-11-01

    Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) is one of the major pests of maize and is in the same feeding guild as the noctuid pests Helicoverpa zea (Boddie) and Helicoverpa armigera (Hübner), recently reported in South and North America. The intraguild interactions of these species were assessed in laboratory and field conditions by determining the survival of larvae in interaction scenarios with non-Bt maize silks and ears. Moreover, a video tracking system was utilized to evaluate behavioral parameters during larval interactions in scenarios with or without food. In intraguild interactions, S. frugiperda had greater survival (55-100%) when competing with Helicoverpa spp. in scenarios where larvae were the same instar or when they were larger (fourth versus second) than their competitor. Frequency and time in food of S. frugiperda larvae were negatively influenced by interactions. Larvae of S. frugiperda moved shorter distances (less than 183.03 cm) compared with H. zea. Overall, S. frugiperda had a competitive advantage over Helicoverpa spp. This study provides significant information regarding noctuid behavior and larval survival during intraguild interactions, which may impact pest prevalence and population dynamics, thereby affecting integrated pest management and insect resistance management of these species in maize. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  13. Hydration of a Large Anionic Charge Distribution - Naphthalene-Water Cluster Anions

    Science.gov (United States)

    Weber, J. Mathias; Adams, Christopher L.

    2010-06-01

    We report the infrared spectra of anionic clusters of naphthalene with up to three water molecules. Comparison of the experimental infrared spectra with theoretically predicted spectra from quantum chemistry calculations allow conclusions regarding the structures of the clusters under study. The first water molecule forms two hydrogen bonds with the π electron system of the naphthalene moiety. Subsequent water ligands interact with both the naphthalene and the other water ligands to form hydrogen bonded networks, similar to other hydrated anion clusters. Naphthalene-water anion clusters illustrate how water interacts with negative charge delocalized over a large π electron system. The clusters are interesting model systems that are discussed in the context of wetting of graphene surfaces and polyaromatic hydrocarbons.

  14. RESPONSIVENESS OF SPATIAL PRICE VOLATILITY TO INCREASED GOVERNMENT PARTICIPATION IN MAIZE GRAIN AND MAIZE MEAL MARKETING IN ZAMBIA

    OpenAIRE

    Syampaku, E.M; Mafimisebi, Taiwo Ejiola

    2014-01-01

    The study analyzed the responsiveness of maize grain and maize meal spatial price volatilities to increased government participation in maize grain marketing in Zambia using descriptive statistics and vector auto-regression (VAR). This was achieved by comparing spatial price volatility means and spatial price means for the period under increased government participation with respective means for periods under limited government participation. Also, spatial price volatilities were regressed ag...

  15. Biotechnology in maize breeding

    Directory of Open Access Journals (Sweden)

    Mladenović-Drinić Snežana

    2004-01-01

    Full Text Available Maize is one of the most important economic crops and the best studied and most tractable genetic system among monocots. The development of biotechnology has led to a great increase in our knowledge of maize genetics and understanding of the structure and behaviour of maize genomes. Conventional breeding practices can now be complemented by a number of new and powerful techniques. Some of these often referred to as molecular methods, enable scientists to see the layout of the entire genome of any organism and to select plants with preferred characteristics by "reading" at the molecular level, saving precious time and resources. DNA markers have provided valuable tools in various analyses ranging from phylogenetic analysis to the positional cloning of genes. Application of molecular markers for genetic studies of maize include: assessment of genetic variability and characterization of germ plasm, identification and fingerprinting of genotypes, estimation of genetic distance, detection of monogamic and quantitative trait loci, marker assisted selection, identification of sequence of useful candidate genes, etc. The development of high-density molecular maps which has been facilitated by PCR-based markers, have made the mapping and tagging of almost any trait possible and serve as bases for marker assisted selection. Sequencing of maize genomes would help to elucidate gene function, gene regulation and their expression. Modern biotechnology also includes an array of tools for introducing or deieting a particular gene or genes to produce plants with novel traits. Development of informatics and biotechnology are resulted in bioinformatic as well as in expansion of microarrey technique. Modern biotechnologies could complement and improve the efficiency of traditional selection and breeding techniques to enhance agricultural productivity.

  16. Supramolecular Chemistry of Selective Anion Recognition for Anions of Environmental Relevance

    International Nuclear Information System (INIS)

    Bowman-James, K.; Wilson, G.; Moyer, B. A.

    2004-01-01

    This project involves the design and synthesis of receptors for oxoanions of environmental importance, including emphasis on high level and low activity waste. Target anions have included primarily oxoanions and a study of the basic concepts behind selective binding of target anions. A primary target has been sulfate because of its deleterious influence on the vitrification of tank wastes

  17. Histone acetylation associated up-regulation of the cell wall related genes is involved in salt stress induced maize root swelling

    OpenAIRE

    Li, Hui; Yan, Shihan; Zhao, Lin; Tan, Junjun; Zhang, Qi; Gao, Fei; Wang, Pu; Hou, Haoli; Li, Lijia

    2014-01-01

    Background Salt stress usually causes crop growth inhibition and yield decrease. Epigenetic regulation is involved in plant responses to environmental stimuli. The epigenetic regulation of the cell wall related genes associated with the salt-induced cellular response is still little known. This study aimed to analyze cell morphological alterations in maize roots as a consequence of excess salinity in relation to the transcriptional and epigenetic regulation of the cell wall related protein ge...

  18. Effect of well-established plasma treatment technology on some physiological characteristics in maize leaves during seedling stage

    International Nuclear Information System (INIS)

    Zhao Hongxiang; Fang Xiangqian; Bian Shaofeng; Zhang Lihua; Tan Guobo; Meng Xiangmeng; Yan Weiping; Liu Yaliang; Sun Ning

    2010-01-01

    In order to provide theoretical references and technical support for application of plasma treatment technology in agriculture, the seeds of maize were treated by well-established plasma treatment technology, then the changes of physiological characteristics of maize leaves during seedling stage were studied. The results indicated that the stress resistance of maize was improved by plasma treatment. The SOD, POD and CAT activities, soluble protein content and soluble sugar content of leaves at two-leave stage, four-leave stage, six-leave stage and eight-leave stage treated by plasma were higher than that of CK, but the MDA content was lower than CK. Although NR activity in leaves at twoleave stage and four-leave stage was slightly lower than CK, but higher than CK at six-leave stage (26.81%) and eightleaves stage (26.75%). Plasma treatment enhanced the nitrogen metabolism capacity, and this tendency was increased remarkable with the growth stages processes. (authors)

  19. Aflatoxin contamination of maize from different storage locations in Ghana

    International Nuclear Information System (INIS)

    Akrobortu, Dick Emmanuel

    2008-05-01

    The contamination of maize by aflatoxins in Ghana is of major concern because of the health hazards associated with it. This study focused on the role played by variations in climatic factors such as relative humidity and rainfall on aflatoxin contamination of maize in different maize storage locations. The study was carried out on samples collected over a period of 10 years (1990 to 1999) in three Districts (Ejura-Sekyedumase, Afram Plains/North-Kwahu and Nkoranza) well – known for maize production in Ghana. The aim was to study the influence of storage locations on levels of aflatoxin contamination and distribution in maize. The findings indicated that significant difference exists between the aflatoxin contamination levels of samples collected from Ejura-Sekyedumase and Nkoranza (p<0.05). Also there was a significant difference between the aflatoxin contamination levels of samples collected from Ejura-Sekyedumase and North-Kwahu (p<0.05). There was no significant difference between the contamination levels of samples from North- Kwahu and Nkoranza (p>0.05). The total aflatoxin levels in samples from Ejura-Sekyedumase, North-Kwahu and Nkoranza over the period were 120.50 ppb, 153.20 ppb and 134.17 ppb respectively. For the period 1990 to 1999 the aflatoxin distributions in the storage locations showed that Nkoranza had the highest level in 1997 and 1999 while North-Kwahu had the highest in 1990, 1991, 1993 and 1998. Similarly, Nkoranza and North-Kwahu had equal levels of 10.50 ppb in 1995. The three locations had equal levels of 9.50 ppb in 1994. On the whole, Ejura-Sekyedumase had fair distribution levels since it was the only location with its highest level far below the acceptable level of 20 ppb for humans. I hereby recommend that further research must be conducted in other districts in the country in order to create awareness of the health hazards associated with the aflatoxin contamination. (au)

  20. Maize (Zea mays L.).

    Science.gov (United States)

    Frame, Bronwyn; Warnberg, Katey; Main, Marcy; Wang, Kan

    2015-01-01

    Agrobacterium tumefaciens-mediated transformation is an effective method for introducing genes into maize. In this chapter, we describe a detailed protocol for genetic transformation of the maize genotype Hi II. Our starting plant material is immature embryos cocultivated with an Agrobacterium strain carrying a standard binary vector. In addition to step-by-step laboratory transformation procedures, we include extensive details in growing donor plants and caring for transgenic plants in the greenhouse.

  1. Growth performance and carcass characteristics of Tanzania Shorthorn Zebu cattle finished on molasses or maize grain with rice or maize by-products

    DEFF Research Database (Denmark)

    Asimwe, I.; Kimambo, A. E.; Laswai, G. H.

    2015-01-01

    Forty five steers (2.5–3.0 years of age and 200±5 (SEM) kg body weight) were allotted randomly into five diets to assess the effects of finishing Tanzania Shorthorn Zebu (TSZ) cattle in feedlot using diets based on either molasses or maize grain combined with maize or rice by-products. The diets...... were hay and concentrate mixtures of hominy feed with molasses (HFMO), rice polishing with molasses (RPMO), hominy feed with maize meal (HFMM), rice polishing with maize meal (RPMM) and a control of maize meal with molasses (MMMO). All concentrate mixtures contained cotton seed cake, mineral mixture.......35 for HFMO) than in maize grain based diets (6.94, 6.73 and 6.19 for RPMM, MMMO and HFMM, respectively). Energy intake was highest (P

  2. Swine slurry application and soil management on double-cropped oat/maize

    Directory of Open Access Journals (Sweden)

    Marlo Adriano Bison Pinto

    2014-06-01

    Full Text Available The swine production in southern Brazil is concentrated in small farms that use residues as a nutrient source for crops of economic interest. This study aimed to evaluate the use of swine slurry associated with tillage systems on double-cropped oat/maize. The experiment was carried out in the 2009/2010 and 2010/2011 cropping seasons, in Taquaruçu do Sul, Rio Grande do Sul State, Brazil. The experimental design was randomized blocks in a factorial scheme, with four replications. Treatments consisted of the interaction of four swine slurry doses (no swine slurry, 20 m3 ha-1, 40 m3 ha-1 and 80 m3 ha-1 and mineral fertilization, in three tillage systems (no-tillage, chiseling and chiseling + disking. The swine slurry application on doublecropped oat/maize increased the dry matter and grain yield. The 80 m3 ha-1 dose provided a response statistically similar to the mineral fertilization recommended for maize. The interaction between the 80 m3 ha-1 dose and the immediate incorporation of slurry into the soil reduced N losses by ammonia volatilization, promoting a significant increase in maize grain yield, when grown on a clayish soil.

  3. Quantitative trait loci for maysin synthesis in maize (Zea mays L.) lines selected for high silk maysin content.

    Science.gov (United States)

    Meyer, J D F; Snook, M E; Houchins, K E; Rector, B G; Widstrom, N W; McMullen, M D

    2007-06-01

    Maysin is a naturally occurring C-glycosyl flavone found in maize (Zea mays L.) silk tissue that confers resistance to corn earworm (Helicoverpa zea, Boddie). Recently, two new maize populations were derived for high silk maysin. The two populations were named the exotic populations of maize (EPM) and the southern inbreds of maize (SIM). Quantitative trait locus (QTL) analysis was employed to determine which loci were responsible for elevated maysin levels in inbred lines derived from the EPM and SIM populations. The candidate genes consistent with QTL position included the p (pericarp color), c2 (colorless2), whp1 (white pollen1) and in1 (intensifier1) loci. The role of these loci in controlling high maysin levels in silks was tested by expression analysis and use of the loci as genetic markers onto the QTL populations. These studies support p, c2 and whp1, but not in1, as loci controlling maysin. Through this study, we determined that the p locus regulates whp1 transcription and that increased maysin in these inbred lines was primarily due to alleles at both structural and regulatory loci promoting increased flux through the flavone pathway by increasing chalcone synthase activity.

  4. Directly dated starch residues document early formative maize (Zea mays L.) in tropical Ecuador.

    Science.gov (United States)

    Zarrillo, Sonia; Pearsall, Deborah M; Raymond, J Scott; Tisdale, Mary Ann; Quon, Dugane J

    2008-04-01

    The study of maize (Zea mays L.) domestication has advanced from questions of its origins to the study-and debate-of its dietary role and the timing of its dispersal from Mexico. Because the investigation of maize's spread is hampered by poor preservation of macrobotanical remains in the Neotropics, research has focused on microbotanical remains whose contexts are often dated by association, leading some to question the dates assigned. Furthermore, some scholars have argued that maize was not introduced to southwestern Ecuador until approximately 4150-3850 calendar years before the present (cal B.P.), that it was used first and foremost as a fermented beverage in ceremonial contexts, and that it was not important in everyday subsistence, challenging previous studies based on maize starch and phytoliths. To further investigate these questions, we analyzed every-day cooking vessels, food-processing implements, and sediments for starch and phytoliths from an archaeological site in southwestern Ecuador constituting a small Early Formative village. Employing a new technique to recover starch granules from charred cooking-pot residues we show that maize was present, cultivated, and consumed here in domestic contexts by at least 5300-4950 cal B.P. Directly dating the residues by accelerator mass spectrometry (AMS) radiocarbon measurement, our results represent the earliest direct dates for maize in Early Formative Ecuadorian sites and provide further support that, once domesticated approximately 9000 calendar years ago, maize spread rapidly from southwestern Mexico to northwestern South America.

  5. Control of Fusarium verticillioides, cause of ear rot of maize, by Pseudomonas fluorescens

    DEFF Research Database (Denmark)

    Nayaka, Siddaiah Chandra; Shankar, Akarere C. Udaya; Reddy, Munagala S.

    2009-01-01

    Abstract BACKGROUND: Maize is one of the staple food crops grown in India. Fusarium verticillioides (Sacc.) Nirenberg is the most important fungal pathogen of maize, associated with diseases such as ear rot and kernel rot. Apart from the disease, it is capable of producing fumonisins, which have...... disease and fumonisin accumulation, and also to study the capacity to promote growth and yield of maize. In vitro assays were conducted to test the efficacy of P. fluorescens as a seed treatment on seed germination, seedling vigour and also the incidence of F. verticillioides in different maize cultivars....... verticillioides and the level of fumonisins to a maximum extent compared with the other treatments. CONCLUSION: The study demonstrates the potential role of P. fluorescens and its formulations in ear rot disease management. The biocontrol potential of this isolate is more suited for fumonisin reduction in maize...

  6. Characterization of pig-associated methicillin-resistant Staphylococcus aureus.

    Science.gov (United States)

    Li, Jun; Jiang, Nansong; Ke, Yuebin; Feßler, Andrea T; Wang, Yang; Schwarz, Stefan; Wu, Congming

    2017-03-01

    Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) have been reported in various countries worldwide. However, although China is one of the biggest pig and pork producers, large-scale studies on pig-associated LA-MRSA from China are scarce. The aims of this study were to analyze 2420 non-duplicate samples collected from pigs at swine farms and slaughterhouses in different regions in China during 2014 for the prevalence of pig-associated MRSA and to determine the antimicrobial resistance pheno- and genotypes of the respective isolates. MRSA isolates were identified in 270 (11.2%) samples. The isolates were characterized by antimicrobial susceptibility testing, multilocus sequence typing (MLST), spa typing, pulsed-field gel electrophoresis (PFGE) and screening for resistance genes. All MRSA isolates belonged to the clonal complex 9 and spa type t899, but showed variable PFGE patterns. All isolates were non-susceptible to oxacillin, cefoxitin, clindamycin, chloramphenicol, florfenicol, ciprofloxacin, and valnemulin. High rates of resistance were also observed for tetracycline (99.6%), erythromycin (97.0%), quinupristin-dalfopristin (97.0%), and gentamicin (80.4%). Three linezolid-non-susceptible isolates containing the multi-resistance gene cfr and nine rifampicin-non-susceptible isolates with mutations in rpoB were detected. Resistance to β-lactams was exclusively associated with mecA, while phenicol resistance was mainly attributable to fexA, except in the three cfr-positive isolates. The pleuromutilin-lincosamide-streptogramin A resistance gene lsa(E) was identified in all MRSA isolates, and no other pleuromutilin resistance genes, except cfr in three isolates, were detected. Pigs are the most important hosts of LA-MRSA in China. Screening for pig-associated MRSA is necessary to monitor changes in epidemiology and characteristics of these important pathogens. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Comparison of different inoculating methods to evaluate the pathogenicity and virulence of Aspergillus niger on two maize hybrids

    Science.gov (United States)

    A two-year field study was conducted to determine the effects of inoculation techniques on the aggressiveness of Aspergillus niger kernel infection in A. flavus resistant and susceptible maize hybrids. Ears were inoculated with the silk-channel, side-needle, and spray techniques 7 days after midsilk...

  8. CERES-Maize model-based simulation of climate change impacts on maize yields and potential adaptive measures in Heilongjiang Province, China.

    Science.gov (United States)

    Lin, Yumei; Wu, Wenxiang; Ge, Quansheng

    2015-11-01

    Climate change would cause negative impacts on future agricultural production and food security. Adaptive measures should be taken to mitigate the adverse effects. The objectives of this study were to simulate the potential effects of climate change on maize yields in Heilongjiang Province and to evaluate two selected typical household-level autonomous adaptive measures (cultivar changes and planting time adjustments) for mitigating the risks of climate change based on the CERES-Maize model. The results showed that flowering duration and maturity duration of maize would be shortened in the future climate and thus maize yield would reduce by 11-46% during 2011-2099 relative to 1981-2010. Increased CO2 concentration would not benefit maize production significantly. However, substituting local cultivars with later-maturing ones and delaying the planting date could increase yields as the climate changes. The results provide insight regarding the likely impacts of climate change on maize yields and the efficacy of selected adaptive measures by presenting evidence-based implications and mitigation strategies for the potential negative impacts of future climate change. © 2014 Society of Chemical Industry.

  9. Near-Isogenic Cry1F-Resistant Strain of Spodoptera frugiperda (Lepidoptera: Noctuidae) to Investigate Fitness Cost Associated With Resistance in Brazil.

    Science.gov (United States)

    Horikoshi, Renato J; Bernardi, Oderlei; Bernardi, Daniel; Okuma, Daniela M; Farias, Juliano R; Miraldo, Leonardo L; Amaral, Fernando S A; Omoto, Celso

    2016-04-01

    Field-evolved resistance to Cry1F maize in Spodoptera frugiperda (J.E. Smith) populations in Brazil was reported in 2014. In this study, to investigate fitness costs, we constructed a near-isogenic S. frugiperda-resistant strain (R-Cry1F) using Cry1F-resistant and Cry1F-susceptible strains sharing a close genetic background. A near-isogenic R-Cry1F strain was obtained by eight repeated backcrossings, each followed by sib-mating and selection among resistant and susceptible strains. Fitness cost parameters were evaluated by comparing the biological performance of resistant, susceptible, and heterozygous strains on artificial diet. Fitness parameters monitored included development time and survival rates of egg, larval, pupal, and egg-to-adult periods; sex ratio; adult longevity; timing of preoviposition, oviposition, and postoviposition; fecundity; and fertility. A fertility life table was also calculated. The near-isogenic R-Cry1F strain showed lower survival rate of eggs (32%), when compared with Sus and reciprocal crosses (41 and 55%, respectively). The number of R-Cry1F insects that completed the life cycle was reduced to ∼25%, compared with the Sus strain with ∼32% reaching the adult stage. The mean generation time (T) of R-Cry1F strain was ∼2 d shorter than R-Cry1F♂×Sus♀ and Sus strains. The reproductive parameters of R-Cry1F strain were similar to the Sus strain. However, fewer females were produced by R-Cry1F strain than R-Cry1F♀×Sus♂ and more females than R-Cry1F♂×Sus♀. In summary, no relevant fitness costs are observed in a near-isogenic Cry1F-resistant strain of S. frugiperda, indicating stability of resistance to Cry1F protein in Brazilian populations of this species in the absence of selection pressure.

  10. Molecular and functional analyses of a maize autoactive NB-LRR protein identify precise structural requirements for activity.

    Directory of Open Access Journals (Sweden)

    Guan-Feng Wang

    2015-02-01

    Full Text Available Plant disease resistance is often mediated by nucleotide binding-leucine rich repeat (NLR proteins which remain auto-inhibited until recognition of specific pathogen-derived molecules causes their activation, triggering a rapid, localized cell death called a hypersensitive response (HR. Three domains are recognized in one of the major classes of NLR proteins: a coiled-coil (CC, a nucleotide binding (NB-ARC and a leucine rich repeat (LRR domains. The maize NLR gene Rp1-D21 derives from an intergenic recombination event between two NLR genes, Rp1-D and Rp1-dp2 and confers an autoactive HR. We report systematic structural and functional analyses of Rp1 proteins in maize and N. benthamiana to characterize the molecular mechanism of NLR activation/auto-inhibition. We derive a model comprising the following three main features: Rp1 proteins appear to self-associate to become competent for activity. The CC domain is signaling-competent and is sufficient to induce HR. This can be suppressed by the NB-ARC domain through direct interaction. In autoactive proteins, the interaction of the LRR domain with the NB-ARC domain causes de-repression and thus disrupts the inhibition of HR. Further, we identify specific amino acids and combinations thereof that are important for the auto-inhibition/activity of Rp1 proteins. We also provide evidence for the function of MHD2, a previously uncharacterized, though widely conserved NLR motif. This work reports several novel insights into the precise structural requirement for NLR function and informs efforts towards utilizing these proteins for engineering disease resistance.

  11. Molecular and functional analyses of a maize autoactive NB-LRR protein identify precise structural requirements for activity.

    Science.gov (United States)

    Wang, Guan-Feng; Ji, Jiabing; El-Kasmi, Farid; Dangl, Jeffery L; Johal, Guri; Balint-Kurti, Peter J

    2015-02-01

    Plant disease resistance is often mediated by nucleotide binding-leucine rich repeat (NLR) proteins which remain auto-inhibited until recognition of specific pathogen-derived molecules causes their activation, triggering a rapid, localized cell death called a hypersensitive response (HR). Three domains are recognized in one of the major classes of NLR proteins: a coiled-coil (CC), a nucleotide binding (NB-ARC) and a leucine rich repeat (LRR) domains. The maize NLR gene Rp1-D21 derives from an intergenic recombination event between two NLR genes, Rp1-D and Rp1-dp2 and confers an autoactive HR. We report systematic structural and functional analyses of Rp1 proteins in maize and N. benthamiana to characterize the molecular mechanism of NLR activation/auto-inhibition. We derive a model comprising the following three main features: Rp1 proteins appear to self-associate to become competent for activity. The CC domain is signaling-competent and is sufficient to induce HR. This can be suppressed by the NB-ARC domain through direct interaction. In autoactive proteins, the interaction of the LRR domain with the NB-ARC domain causes de-repression and thus disrupts the inhibition of HR. Further, we identify specific amino acids and combinations thereof that are important for the auto-inhibition/activity of Rp1 proteins. We also provide evidence for the function of MHD2, a previously uncharacterized, though widely conserved NLR motif. This work reports several novel insights into the precise structural requirement for NLR function and informs efforts towards utilizing these proteins for engineering disease resistance.

  12. Aggressiveness of Cephalosporium maydis causing late wilt of maize in Spain.

    Science.gov (United States)

    García-Carneros, A B; Girón, I; Molinero-Ruiz, L

    2012-01-01

    root weight reductions were also associated to a significant low weight of above-ground parts. Considering all the symptoms analysed and their progression in the maize plants, our results reveal that a diversity of aggressiveness exists among isolates of C. maydis. The need for a characterization of maize genotypes by their reaction against highly aggressive isolates of the fungus in the Iberian Peninsula is suggested. This study is a first step towards a recommendation of crop varieties that are tolerant to C. maydis in different areas of the Iberian Peninsula. Future research aims at studying the relationship between aggressiveness levels, molecular characteristics and geographical origin whithin C. maydis.

  13. Bulk soil and maize rhizosphere resistance genes, mobile genetic elements and microbial communities are differently impacted by organic and inorganic fertilization

    DEFF Research Database (Denmark)

    Wolters, Birgit; Jacquiod, Samuel Jehan Auguste; Sørensen, Søren Johannes

    2018-01-01

    Organic soil fertilizers, such as livestock manure and biogas digestate, frequently contain bacteria carrying resistance genes (RGs) to antimicrobial substances and mobile genetic elements (MGEs). The effects of different fertilizers (inorganic, manure, digestate) on RG and MGE abundance...... and microbial community composition were investigated in a field plot experiment. The relative abundances of RGs [sul1, sul2, tet(A), tet(M), tet(Q), tet(W), qacEΔ1/qacE] and MGEs [intI1, intI2, IncP-1, IncP-1ε and LowGC plasmids] in total community (TC)-DNA from organic fertilizers, bulk soil and maize......, integrons and few genera affiliated to Bacteroidetes and Firmicutes in bulk soil, while digestate increased sul2, tet(W) and intI2. At harvest, treatment effects vanished in bulk soil. However, organic fertilizer effects were still detectable in the rhizosphere for RGs [manure: intI1, sul1; digestate: tet...

  14. quixotic coupling between irrigation system and maize-cowpea

    African Journals Online (AJOL)

    ACSS

    number row-1 and maize grain yield, respectively. The ridge ... Key Words: Furrow irrigation, water use efficiency, Zea mays. RÉSUMÉ ... important in arid and semi-arid regions, with ... as maize) canopy is not able to intercept all the solar radiation during the growth period. ... Intercropping maize and legumes considerably ...

  15. Pathogenicity of fumonisin-producing and nonproducing strains of Aspergillus species in section Nigri to maize ears and seedlings

    Science.gov (United States)

    Species of Aspergillus section Nigri are commonly associated with maize kernels, and some strains can produce fumonisin mycotoxins. However, there is little information about the extent to which these fungi contribute to fumonisin contamination in grain, the damage they cause to maize ears, or their...

  16. Methods and systems for measuring anions

    KAUST Repository

    Masih, Dilshad; Mohammed, Omar F.; Aly, Shawkat M.; Alarousu, Erkki

    2016-01-01

    Embodiments of the present disclosure provide for methods for detecting the presence and/or concentration of anions in a solution, systems for detecting the presence and/or concentration of anions in a solution, anion sensor systems, and the like.

  17. Methods and systems for measuring anions

    KAUST Repository

    Masih, Dilshad

    2016-08-18

    Embodiments of the present disclosure provide for methods for detecting the presence and/or concentration of anions in a solution, systems for detecting the presence and/or concentration of anions in a solution, anion sensor systems, and the like.

  18. Socio-economic assessment on maize production and adoption of open pollinated improved varieties in Dang, Nepal

    Directory of Open Access Journals (Sweden)

    Sanjiv Subedi

    2017-12-01

    Full Text Available Research was conducted from February to May, 2017 for socioeconomic assessment on maize production and adoption of open pollinated improved maize varieties in Dang district of Nepal. Altogether, 100 samples were taken by simple random sampling from the major maize growing areas and relevant publications were reviewed. Focal Group Discussion and Key Informant Survey were also done. Descriptive statistics, unpaired t-test, probit regression and indexing were used for data analysis using statistical tools- SPSS, STATA and MS-Excel. Probit econometric model revealed that ethnicity (1% level, gender (5% level, area under open pollinated improved maize (1% level, seed source dummy (1 % level and number of visits by farmers to agrovet (5% level significantly determined the adoption of open pollinated improved maize varieties. In addition, unpaired t-test revealed that the productivity of open pollinated improved maize varieties was significantly higher (at 1% level than local; also, the multinational companies' hybrids showed significantly higher productivity (at 1% level when compared to open pollinated improved varieties. Furthermore, indexing identified- lack of availability of quality seeds and fertilizers (I= 0.86 as the major problem associated with the maize production. Giving aggressive subsidy on open pollinated improved seeds and dealership to registered agrovets for selling the subsidy seeds could enhance the adoption. Moreover, government organizations working in the areas of agricultural extension and research must focus on adoption of open pollinated improved maize varieties among the farmers, substituting the local and developing the high yielding hybrid varieties in Nepal to increase the maize productivity.

  19. Propanol in maize silage at Danish dairy farms

    DEFF Research Database (Denmark)

    Raun, Birgitte Marie Løvendahl; Kristensen, Niels Bastian

    2010-01-01

    The objective of the present study was to investigate the prevalence maize silage containing propanol, the seasonal variation in propanol content of maize silage, and correlations between propanol and other fermentation products in maize silage collected from 20 randomly selected Danish dairy farms...... farms, the maize silage had ≥5 g propanol/kg DM. The present study indicates that dairy cows in Denmark are commonly exposed to propanol and that approximately 20% of the dairy cows will have an intake in the range of 75-100 g propanol/d under common feeding conditions....

  20. Effect of alkaline cooking of maize on the content of fumonisins B1 and B2 and their hydrolysed forms.

    Science.gov (United States)

    De Girolamo, A; Lattanzio, V M T; Schena, R; Visconti, A; Pascale, M

    2016-02-01

    The effect of nixtamalization on the content of fumonisins (FBs), hydrolysed (HFBs) and partially hydrolysed (PHFBs) fumonisins in maize was investigated at laboratory-scale. Maize naturally contaminated with FBs and PHFBs was cooked with lime. Starting raw maize, steeping and washing waters and final masa fractions were analysed for toxin content. Control-cooking experiments without lime were also carried out. The nixtamalization reduced the amount of FBs and PHFBs in masa and converted them to HFBs. However, the three forms of fumonisins collected in all fractions amounted to 183%, indicating that nixtamalization made available forms of matrix-associated fumonisins that were then converted to their hydrolysed forms. Control-cooking enhanced FBs and PHFBs reduction, due to the solubility of fumonisins in water during the steeping process, but did not form HFBs. These findings indicate that benefits associated with enhancing the nutritional value of nixtamalized maize are also associated with a safer product in terms of fumonisin contamination. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. ZmbZIP60 mRNA is spliced in maize in response to ER stress

    Directory of Open Access Journals (Sweden)

    Li Yanjie

    2012-03-01

    Full Text Available Abstract Background Adverse environmental conditions produce ER stress and elicit the unfolded protein response (UPR in plants. Plants are reported to have two "arms" of the ER stress signaling pathway-one arm involving membrane-bound transcription factors and the other involving a membrane-associated RNA splicing factor, IRE1. IRE1 in yeast to mammals recognizes a conserved twin loop structure in the target RNA. Results A segment of the mRNA encoding ZmbZIP60 in maize can be folded into a twin loop structure, and in response to ER stress this mRNA is spliced, excising a 20b intron. Splicing converts the predicted protein from a membrane-associated transcription factor to one that is targeted to the nucleus. Splicing of ZmbZIP60 can be elicited in maize seedlings by ER stress agents such as dithiothreitol (DTT or tunicamycin (TM or by heat treatment. Younger, rather than older seedlings display a more robust splicing response as do younger parts of leaf, along a developmental gradient in a leaf. The molecular signature of an ER stress response in plants includes the upregulation of Binding Protein (BIP genes. Maize has numerous BIP-like genes, and ER stress was found to upregulate one of these, ZmBIPb. Conclusions The splicing of ZmbZIP60 mRNA is an indicator of ER stress in maize seedlings resulting from adverse environmental conditions such as heat stress. ZmbZIP60 mRNA splicing in maize leads predictively to the formation of active bZIP transcription factor targeted to the nucleus to upregulate stress response genes. Among the genes upregulated by ER stress in maize is one of 22 BIP-like genes, ZmBIPb.

  2. Sub-Saharan African maize-based foods

    NARCIS (Netherlands)

    Ekpa, Onu; Palacios-Rojas, Natalia; Kruseman, Gideon; Fogliano, Vincenzo; Linnemann, Anita R.

    2018-01-01

    The demand for maize in Sub-Saharan Africa will triple by 2050 due to rapid population growth, while challenges from climate change will threaten agricultural productivity. Most maize breeding programmes have focused on improving agronomic properties and have paid relatively little attention to

  3. Phosphazene-promoted anionic polymerization

    KAUST Repository

    Zhao, Junpeng

    2014-01-01

    In the recent surge of metal-free polymerization techniques, phosphazene bases have shown their remarkable potential as organic promoters/catalysts for the anionic polymerization of various types of monomers. By complexation with the counterion (e.g. proton or lithium cation), phosphazene base significantly improve the nucleophilicity of the initiator/chain-end resulting in rapid and usually controlled anionic/quasi-anionic polymerization. In this review, we will introduce the general mechanism, i.e. in situ activation (of initiating sites) and polymerization, and summarize the applications of such a mechanism on macromolecular engineering toward functionalized polymers, block copolymers and complex macromolecular architectures.

  4. Lack of detectable allergenicity in genetically modified maize containing "Cry" proteins as compared to native maize based on in silico & in vitro analysis.

    Directory of Open Access Journals (Sweden)

    Chandni Mathur

    Full Text Available Genetically modified, (GM crops with potential allergens must be evaluated for safety and endogenous IgE binding pattern compared to native variety, prior to market release.To compare endogenous IgE binding proteins of three GM maize seeds containing Cry 1Ab,1Ac,1C transgenic proteins with non GM maize.An integrated approach of in silico & in vitro methods was employed. Cry proteins were tested for presence of allergen sequence by FASTA in allergen databases. Biochemical assays for maize extracts were performed. Specific IgE (sIgE and Immunoblot using food sensitized patients sera (n = 39 to non GM and GM maize antigens was performed.In silico approaches, confirmed for non sequence similarity of stated transgenic proteins in allergen databases. An insignificant (p> 0.05 variation in protein content between GM and non GM maize was observed. Simulated Gastric Fluid (SGF revealed reduced number of stable protein fractions in GM then non GM maize which might be due to shift of constituent protein expression. Specific IgE values from patients showed insignificant difference in non GM and GM maize extracts. Five maize sensitized cases, recognized same 7 protein fractions of 88-28 kD as IgE bindng in both GM and non-GM maize, signifying absence of variation. Four of the reported IgE binding proteins were also found to be stable by SGF.Cry proteins did not indicate any significant similarity of >35% in allergen databases. Immunoassays also did not identify appreciable differences in endogenous IgE binding in GM and non GM maize.

  5. Partitioning of hydrophobic pesticides within a soil-water-anionic surfactant system.

    Science.gov (United States)

    Wang, Peng; Keller, Arturo A

    2009-02-01

    Surfactants can be added to pesticide-contaminated soils to enhance the treatment efficiency of soil washing. Our results showed that pesticide (atrazine and diuron) partitioning and desorbability within a soil-water-anionic surfactant system is soil particle-size dependent and is significantly influenced by the presence of anionic surfactant. Anionic surfactant (linear alkylbenzene sulphonate, LAS) sorption was influenced by its complexation with both the soluble and exchangeable divalent cations in soils (e.g. Ca2+, Mg2+). In this study, we propose a new concept: soil system hardness which defines the total amount of soluble and exchangeable divalent cations associated with a soil. Our results showed that anionic surfactant works better with soils having lower soil system hardness. It was also found that the hydrophobic organic compounds (HOCs) sorbed onto the LAS-divalent cation precipitate, resulting in a significant decrease in the aqueous concentration of HOC. Our results showed that the effect of exchangeable cations and sorption of HOC onto the surfactant precipitates needs to be considered to accurately predict HOC behavior within soil-water-anionic surfactant systems.

  6. a study of technical inefficiencies of maize farmers within and ...

    African Journals Online (AJOL)

    p2333147

    frontier production functions were estimated for a sample of maize farmers within and outside the .... the normal distributions with the same variance, σ2, such that the mean,. µit, associated with the technical inefficiency effect, uit, is defined by.

  7. Association of alkali and alkaline earth metal cations with radical-anions of 9-fluorenone and 9.10-anthraquinone in dimethyl formamide medium

    International Nuclear Information System (INIS)

    Karpinets, A.P.; Bezuglyj, V.D.; Svetlichnaya, T.M.

    1988-01-01

    The polarographic method is used to estimate the stability of associates formed in dimethyl formamide by the products of one-electron reduction of 9-fluorenone and 9.10-anthraquinone with cations of alkali and alkali earth metals. It is shown that the strength of 9-fluorenone and 9.10-anthraquinone radical anion associates studied increases with cation charge increase and decrease of its crystallographic radius

  8. Early colonization pattern of maize (Zea mays L. Poales, Poaceae roots by Herbaspirillum seropedicae (Burkholderiales, Oxalobacteraceae

    Directory of Open Access Journals (Sweden)

    Rose A. Monteiro

    2008-12-01

    Full Text Available The bacterium Herbaspirillum seropedicae is an endophytic diazotroph found in several plants, including economically important poaceous species. However, the mechanisms involved in the interaction between H. seropedicae and these plants are not completely characterized. We investigated the attachment of Herbaspirillum to maize roots and the invasion of the roots by this bacterium using H. seropedicae strain SMR1 transformed with the suicide plasmid pUTKandsRed, which carries a mini-Tn5 transposon containing the gene for the Discosoma red fluorescent protein (Dsred constitutively expressed together with the kanamycin resistance gene. Integration of the mini-Tn5 into the bacterial chromosome yielded the mutant H. seropedicae strain RAM4 which was capable of expressing Dsred and could be observed on and inside fresh maize root samples. Confocal microscopy of maize roots inoculated with H. seropedicae three days after germination showed that H. seropedicae cell were attached to the root surface 30 min after inoculation, were visible in the internal tissues after twenty-four hours and in the endodermis, the central cylinder and xylem after three days.

  9. Fungal Diversity of Maize (Zea Mays L. Grains

    Directory of Open Access Journals (Sweden)

    Gulbis Kaspars

    2016-06-01

    Full Text Available Maize is becoming more and more important crop for dairy farming as forage and as substrate for biogas production. The mycotoxin producing fungi can spoil feed, reduce cattle productivity and cause health problems. The aim of this research was to study the mycoflora of maize grains in order to clarify the fungal composition and verify the presence of potential mycotoxin producing fungi. The grain samples were collected from different maize hybrid performance trial in Research and Study farm “Vecauce” of Latvia University of Agriculture in 2014. The fungi from 14 genera were isolated from surface sterilized grains. The most abundant were Alternaria, Fusarium and Penicillium spp. Mycotoxin producing fungi are present in maize grain mycoflora, and there is a risk that maize production can contain mycotoxins.

  10. Exogenous application of urea and a urease inhibitor improves drought stress tolerance in maize (Zea mays L.).

    Science.gov (United States)

    Gou, Wei; Zheng, Pufan; Tian, Li; Gao, Mei; Zhang, Lixin; Akram, Nudrat Aisha; Ashraf, Muhammad

    2017-05-01

    Drought is believed to cause many metabolic changes which affect plant growth and development. However, it might be mitigated by various inorganic substances, such as nitrogen. Thus, the study was carried out to investigate the effect of foliar-applied urea with or without urease inhibitor N-(n-butyl) thiophosphoric triamide (NBPT) on a maize cultivar under drought stress simulated by 15% (w/v) polyethylene glycol 6000. Foliar-applied urea resulted in a significant increase in plant dry weight, relative water content, and photosynthetic pigments under water stress condition. Furthermore, the activities of superoxide dismutase (SOD), peroxidase (POD), and hydrogen peroxidase (CAT), were enhanced with all spraying treatments under drought stress, which led to decreases in accumulation of hydrogen peroxide (H 2 O 2 ), superoxide anion ([Formula: see text]) and malondialdehyde (MDA). The contents of soluble protein and soluble sugar accumulated remarkably with urea-applied under drought stress condition. Moreover, a further enhancement in above metabolites was observed by spraying a mixture of urea and urease inhibitor as compared to urea sprayed only. Taken together, our findings show that foliar application of urea and a urease inhibitor could significantly enhance drought tolerance of maize through protecting photosynthetic apparatus, activating antioxidant defense system and improving osmoregulation.

  11. Downregulation and Mutation of a Cadherin Gene Associated with Cry1Ac Resistance in the Asian Corn Borer, Ostrinia furnacalis (Guenée

    Directory of Open Access Journals (Sweden)

    Tingting Jin

    2014-09-01

    Full Text Available Development of resistance in target pests is a major threat to long-term use of transgenic crops expressing Bacillus thuringiensis (Bt Cry toxins. To manage and/or delay the evolution of resistance in target insects through the implementation of effective strategies, it is essential to understand the basis of resistance. One of the most important mechanisms of insect resistance to Bt crops is the alteration of the interactions between Cry toxins and their receptors in the midgut. A Cry1Ac-selected strain of Asian corn borer (ACB, Ostrinia furnacalis, a key pest of maize in China, evolved three mutant alleles of a cadherin-like protein (OfCAD (MPR-r1, MPR-r2 and MPR-r3, which mapped within the toxin-binding region (TBR. Each of the three mutant alleles possessed two or three amino acid substitutions in this region, especially Thr1457→Ser. In highly resistant larvae (ACB-Ac200, MPR-r2 had a 26-amino acid residue deletion in the TBR, which resulted in reduced binding of Cry1Ac compared to the MPR from the susceptible strain, suggesting that the number of amino acid deletions influences the level of resistance. Furthermore, downregulation of OfCAD gene (ofcad transcription was observed in the Cry1Ac resistant strain, ACB-Ac24, suggesting that Cry1Ac resistance in ACB is associated with the downregulation of the transcript levels of the cadherin-like protein gene. The OfCAD identified from ACB exhibited a high degree of similarity to other members of the cadherin super-family in lepidopteran species.

  12. Temperature affects radiation use efficiency in maize

    International Nuclear Information System (INIS)

    Andrade, F.H.; Uhart, S.A.; Cirilo, A.

    1993-01-01

    The objective of this work was to study, under field conditions, the effect of temperature on radiation use efficiency (RUE) of maize. Field evidence of the negative effect of low temperature on this variable is lacking. Experiments with different sowing dates and five years of experimentation with October plantings provided a range of average temperatures during the vegetative period from 15.8 to 20.9°C. Delaying the sowing time from September to November produced a highly significant increase in RUE. There was a positive association between RUE and mean temperature from emergence to flowering. Efficiencies varied from 2.27 to 3.17 g of dry matter per MJ of intercepted photosynthetically active radiation for October plantings of five different years. With these data, a positive and significant association between RUE and mean temperature during the November–December vegetative period was found. Across years and planting dates, RUE and mean temperature during the vegetative period were closely correlated (r = 0.87). The regression equation was RUE = −1.8 + 0.07 T. Based on this evidence, it was concluded that low temperatures reduce RUE in maize. (author)

  13. Zinc resistance within swine associated methicillin resistant Staphylococcus aureus (MRSA) isolates in the USA is associated with MLST lineage

    Science.gov (United States)

    Zinc resistance in livestock-associated methicillin resistant Staphylococcus aureus (LA-MRSA) is mediated by the czrC gene co-located with the mecA gene, encoding methicillin resistance, on the type V SCCmec element. Since the czrC gene and the mecA gene are co-located on the SCCmec element, it has ...

  14. Stress Sensitivity Is Associated with Differential Accumulation of Reactive Oxygen and Nitrogen Species in Maize Genotypes with Contrasting Levels of Drought Tolerance

    Science.gov (United States)

    Yang, Liming; Fountain, Jake C.; Wang, Hui; Ni, Xinzhi; Ji, Pingsheng; Lee, Robert D.; Kemerait, Robert C.; Scully, Brian T.; Guo, Baozhu

    2015-01-01

    Drought stress decreases crop growth, yield, and can further exacerbate pre-harvest aflatoxin contamination. Tolerance and adaptation to drought stress is an important trait of agricultural crops like maize. However, maize genotypes with contrasting drought tolerances have been shown to possess both common and genotype-specific adaptations to cope with drought stress. In this research, the physiological and metabolic response patterns in the leaves of maize seedlings subjected to drought stress were investigated using six maize genotypes including: A638, B73, Grace-E5, Lo964, Lo1016, and Va35. During drought treatments, drought-sensitive maize seedlings displayed more severe symptoms such as chlorosis and wilting, exhibited significant decreases in photosynthetic parameters, and accumulated significantly more reactive oxygen species (ROS) and reactive nitrogen species (RNS) than tolerant genotypes. Sensitive genotypes also showed rapid increases in enzyme activities involved in ROS and RNS metabolism. However, the measured antioxidant enzyme activities were higher in the tolerant genotypes than in the sensitive genotypes in which increased rapidly following drought stress. The results suggest that drought stress causes differential responses to oxidative and nitrosative stress in maize genotypes with tolerant genotypes with slower reaction and less ROS and RNS production than sensitive ones. These differential patterns may be utilized as potential biological markers for use in marker assisted breeding. PMID:26492235

  15. Stress Sensitivity Is Associated with Differential Accumulation of Reactive Oxygen and Nitrogen Species in Maize Genotypes with Contrasting Levels of Drought Tolerance

    Directory of Open Access Journals (Sweden)

    Liming Yang

    2015-10-01

    Full Text Available Drought stress decreases crop growth, yield, and can further exacerbate pre-harvest aflatoxin contamination. Tolerance and adaptation to drought stress is an important trait of agricultural crops like maize. However, maize genotypes with contrasting drought tolerances have been shown to possess both common and genotype-specific adaptations to cope with drought stress. In this research, the physiological and metabolic response patterns in the leaves of maize seedlings subjected to drought stress were investigated using six maize genotypes including: A638, B73, Grace-E5, Lo964, Lo1016, and Va35. During drought treatments, drought-sensitive maize seedlings displayed more severe symptoms such as chlorosis and wilting, exhibited significant decreases in photosynthetic parameters, and accumulated significantly more reactive oxygen species (ROS and reactive nitrogen species (RNS than tolerant genotypes. Sensitive genotypes also showed rapid increases in enzyme activities involved in ROS and RNS metabolism. However, the measured antioxidant enzyme activities were higher in the tolerant genotypes than in the sensitive genotypes in which increased rapidly following drought stress. The results suggest that drought stress causes differential responses to oxidative and nitrosative stress in maize genotypes with tolerant genotypes with slower reaction and less ROS and RNS production than sensitive ones. These differential patterns may be utilized as potential biological markers for use in marker assisted breeding.

  16. The Conserved and Unique Genetic Architecture of Kernel Size and Weight in Maize and Rice.

    Science.gov (United States)

    Liu, Jie; Huang, Juan; Guo, Huan; Lan, Liu; Wang, Hongze; Xu, Yuancheng; Yang, Xiaohong; Li, Wenqiang; Tong, Hao; Xiao, Yingjie; Pan, Qingchun; Qiao, Feng; Raihan, Mohammad Sharif; Liu, Haijun; Zhang, Xuehai; Yang, Ning; Wang, Xiaqing; Deng, Min; Jin, Minliang; Zhao, Lijun; Luo, Xin; Zhou, Yang; Li, Xiang; Zhan, Wei; Liu, Nannan; Wang, Hong; Chen, Gengshen; Li, Qing; Yan, Jianbing

    2017-10-01

    Maize ( Zea mays ) is a major staple crop. Maize kernel size and weight are important contributors to its yield. Here, we measured kernel length, kernel width, kernel thickness, hundred kernel weight, and kernel test weight in 10 recombinant inbred line populations and dissected their genetic architecture using three statistical models. In total, 729 quantitative trait loci (QTLs) were identified, many of which were identified in all three models, including 22 major QTLs that each can explain more than 10% of phenotypic variation. To provide candidate genes for these QTLs, we identified 30 maize genes that are orthologs of 18 rice ( Oryza sativa ) genes reported to affect rice seed size or weight. Interestingly, 24 of these 30 genes are located in the identified QTLs or within 1 Mb of the significant single-nucleotide polymorphisms. We further confirmed the effects of five genes on maize kernel size/weight in an independent association mapping panel with 540 lines by candidate gene association analysis. Lastly, the function of ZmINCW1 , a homolog of rice GRAIN INCOMPLETE FILLING1 that affects seed size and weight, was characterized in detail. ZmINCW1 is close to QTL peaks for kernel size/weight (less than 1 Mb) and contains significant single-nucleotide polymorphisms affecting kernel size/weight in the association panel. Overexpression of this gene can rescue the reduced weight of the Arabidopsis ( Arabidopsis thaliana ) homozygous mutant line in the AtcwINV2 gene (Arabidopsis ortholog of ZmINCW1 ). These results indicate that the molecular mechanisms affecting seed development are conserved in maize, rice, and possibly Arabidopsis. © 2017 American Society of Plant Biologists. All Rights Reserved.

  17. Possibly similar genetic basis of resistance to Bacillus thuringiensis Cry1Ab protein in 3 resistant colonies of the sugarcane borer collected from Louisiana, USA.

    Science.gov (United States)

    Yang, Fei; Chen, Mao; Gowda, Anilkumar; Kerns, David L; Huang, Fangneng

    2018-04-01

    The sugarcane borer, Diatraea saccharalis (F.), is a major maize borer pest and a target of transgenic maize expressing Bacillus thuringiensis (Bt) proteins in South America and the mid-southern region of the United States. Evolution of resistance in target pest populations is a great threat to the long-term efficacy of Bt crops. In this study, we compared the genetic basis of resistance to Cry1Ab protein in 3 resistant colonies of sugarcane borer established from field populations in Louisiana, USA. Responses of larvae to the Cry1Ab protein for the parental and 10 other cross colonies were assayed in a diet-incorporated bioassay. All 3 resistant colonies were highly resistant to the Cry1Ab protein with a resistance ratio of >555.6 fold. No maternal effect or sex linkage was evident for the resistance in the 3 colonies; and the resistance was functionally nonrecessive at the Cry1Ab concentrations of ≤ 3.16 μg/g, but it became recessive at ≥10 μg/g. In an interstrain complementation test for allelism, the F 1 progeny from crosses between any 2 of the 3 resistant colonies exhibited the similar resistance levels as their parental colonies, indicating that the 3 colonies most likely shared a locus of Cry1Ab resistance. Results generated from this study should provide useful information in developing effective strategies for managing Bt resistance in the insect. © 2016 Institute of Zoology, Chinese Academy of Sciences.

  18. Bacterial communities in the rhizosphere of amilaceous maize (Zea mays L. as assessed by pyrosequencing

    Directory of Open Access Journals (Sweden)

    David Correa-Galeote

    2016-07-01

    Full Text Available Maize (Zea mays L. is the staple diet of the native peasants in the Quechua region of the Peruvian Andes who continue growing it in small plots called chacras following ancestral traditions. The abundance and structure of bacterial communities associated with the roots of amilaceous maize has not been studied in Andean chacras. Accordingly, the main objective of this study was to describe the rhizospheric bacterial diversity of amilaceous maize grown either in the presence or the absence of bur clover cultivated in soils from the Quechua maize belt. Three 16S rRNA gene libraries, one corresponding to sequences of bacteria from bulk soil of a chacra maintained under fallow conditions, the second from the rhizosphere of maize-cultivated soils, and the third prepared from rhizospheric soil of maize cultivated in intercropping with bur clover were examined using pyrosequencing tags spanning the V4 and V5 hypervariable regions of the gene. A total of 26031 sequences were found that grouped into 5955 distinct operational taxonomic units which distributed in 309 genera. The numbers of OTUs in the libraries from the maize-cultivated soils were significantly higher than those found in the libraries from bulk soil. One hundred ninety seven genera were found in the bulk soil library and 234 and 203 were in those from the maize and maize/bur clover-cultivated soils. Sixteen out of the 309 genera had a relative abundance higher than 0.5% and the were (in decreasing order of abundance Gp4, Gp6, Flavobacterium, Subdivision3 genera incertae sedis of the Verrucomicrobia phylum, Gemmatimonas, Dechloromonas, Ohtaekwangia, Rhodoferax, Gaiella, Opitutus, Gp7, Spartobacteria genera incertae sedis, Terrimonas, Gp5, Steroidobacter and Parcubacteria genera incertae sedis. Genera Gp4 and Gp6 of the Acidobacteria, Gemmatimonas and Rhodoferax were the most abundant in bulk soil, whereas Flavobacterium, Dechloromonas and Ohtaekwangia were the main genera in the rhizosphere

  19. Measurements of water uptake of maize roots: the key function of lateral roots

    Science.gov (United States)

    Ahmed, M. A.; Zarebanadkouki, M.; Kroener, E.; Kaestner, A.; Carminati, A.

    2014-12-01

    Maize (Zea mays L.) is one of the most important crop worldwide. Despite its importance, there is limited information on the function of different root segments and root types of maize in extracting water from soils. Therefore, the aim of this study was to investigate locations of root water uptake in maize. We used neutron radiography to: 1) image the spatial distribution of maize roots in soil and 2) trace the transport of injected deuterated water (D2O) in soil and roots. Maizes were grown in aluminum containers (40×38×1 cm) filled with a sandy soil. When the plants were 16 days old, we injected D2O into selected soil regions containing primary, seminal and lateral roots. The experiments were performed during the day (transpiring plants) and night (not transpiring plants). The transport of D2O into roots was simulated using a new convection-diffusion numerical model of D2O transport into roots. By fitting the observed D2O transport we quantified the diffusional permeability and the water uptake of the different root segments. The maize root architecture consisted of a primary root, 4-5 seminal roots and many lateral roots connected to the primary and seminal roots. Laterals emerged from the proximal 15 cm of the primary and seminal roots. Water uptake occurred primarily in lateral roots. Lateral roots had the highest diffusional permeability (9.4×10-7), which was around six times higher that the diffusional permeability of the old seminal segments (1.4×10-7), and two times higher than the diffusional permeability of the young seminal segments (4.7×10-7). The radial flow of D2O into the lateral (6.7×10-5 ) was much higher than in the young seminal roots (1.1×10-12). The radial flow of D2O into the old seminal was negligible. We concluded that the function of the primary and seminal roots was to collect water from the lateral roots and transport it to the shoot. A maize root system with lateral roots branching from deep primary and seminal roots would be

  20. Genomic variation in recently collected maize landraces from Mexico

    Directory of Open Access Journals (Sweden)

    María Clara Arteaga

    2016-03-01

    Full Text Available The present dataset comprises 36,931 SNPs genotyped in 46 maize landraces native to Mexico as well as the teosinte subspecies Zea maiz ssp. parviglumis and ssp. mexicana. These landraces were collected directly from farmers mostly between 2006 and 2010. We accompany these data with a short description of the variation within each landrace, as well as maps, principal component analyses and neighbor joining trees showing the distribution of the genetic diversity relative to landrace, geographical features and maize biogeography. High levels of genetic variation were detected for the maize landraces (HE = 0.234 to 0.318 (mean 0.311, while slightly lower levels were detected in Zea m. mexicana and Zea m. parviglumis (HE = 0.262 and 0.234, respectively. The distribution of genetic variation was better explained by environmental variables given by the interaction of altitude and latitude than by landrace identity. This dataset is a follow up product of the Global Native Maize Project, an initiative to update the data on Mexican maize landraces and their wild relatives, and to generate information that is necessary for implementing the Mexican Biosafety Law. Keywords: Maize, Teosinte, Maize SNP50K BeadChip, Mexican landraces, Proyecto Global de Maíces Nativos

  1. Anion-π Catalysts with Axial Chirality.

    Science.gov (United States)

    Wang, Chao; Matile, Stefan

    2017-09-04

    The idea of anion-π catalysis is to stabilize anionic transition states by anion-π interactions on aromatic surfaces. For asymmetric anion-π catalysis, π-acidic surfaces have been surrounded with stereogenic centers. This manuscript introduces the first anion-π catalysts that operate with axial chirality. Bifunctional catalysts with tertiary amine bases next to π-acidic naphthalenediimide planes are equipped with a bulky aromatic substituent in the imide position to produce separable atropisomers. The addition of malonic acid half thioesters to enolate acceptors is used for evaluation. In the presence of a chiral axis, the selective acceleration of the disfavored but relevant enolate addition was much better than with point chirality, and enantioselectivity could be observed for the first time for this reaction with small-molecule anion-π catalysts. Enantioselectivity increased with the π acidity of the π surface, whereas the addition of stereogenic centers around the aromatic plane did not cause further improvements. These results identify axial chirality of the active aromatic plane generated by atropisomerism as an attractive strategy for asymmetric anion-π catalysis. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Strategic Marketing Problems in the Uganda Maize Seed Industry

    OpenAIRE

    Larson, Donald W.; Mbowa, Swaibu

    2004-01-01

    Strategic marketing issues and challenges face maize seed marketing firms as farmers increasingly adopt hybrid varieties in a modernizing third world country such as Uganda. The maize seed industry of Uganda has changed dramatically from a government owned, controlled, and operated industry to a competitive market oriented industry with substantial private firm investment and participation. The new maize seed industry is young, dynamic, growing and very competitive. The small maize seed marke...

  3. A model of a successful utilization of a high genetic potential of maize yield

    Directory of Open Access Journals (Sweden)

    Pavlov Milovan

    2008-01-01

    Full Text Available The principle of a system, defined as a ZP system, implying corresponding relationship among research, seed production and seed marketing, is that each segment within the system has its tasks and responsibilities, as well as, a clear interest. This system was established at the Maize Research Institute, Zemun Polje, almost half a century ago. The crucial characteristic is that this system encompasses obtained results of scientific accomplishments (patent - a released hybrid, optimal utilisation of the environmental conditions, facilities for seed drying, processing and packing, staff and transport capacities. The ZP system provides the economic interest of all participants in studies and the maize seed production. The fundamental base of the quality seed production within the ZP system is a multidisciplinary programme on maize breeding, as well as, 535 released hybrids with standard and specific traits. According to regulations in foreign countries, approximately 100 ZP maize hybrids have been released abroad. Agroecological conditions in Serbia are favorable for the development of the best genotypes and the production of basic and certified maize seed. There 10 processing plants that apply recent technologies in the maize seed processing procedure. Several generations of experts have been trained and gained experience within the maize seed production. Three seed testing laboratories have been accredited by the International Seed Testing Association. According to regulations in Serbia, monitoring of seed production under field conditions, and further on, during the processing practice is done only by designate authorities. This study presents one of successful systems of the seed production organization applicable in countries with similar conditions.

  4. Identification of Genes Potentially Associated with the Fertility Instability of S-Type Cytoplasmic Male Sterility in Maize via Bulked Segregant RNA-Seq.

    Directory of Open Access Journals (Sweden)

    Aiguo Su

    Full Text Available S-type cytoplasmic male sterility (CMS-S is the largest group among the three major types of CMS in maize. CMS-S exhibits fertility instability as a partial fertility restoration in a specific nuclear genetic background, which impedes its commercial application in hybrid breeding programs. The fertility instability phenomenon of CMS-S is controlled by several minor quantitative trait locus (QTLs, but not the major nuclear fertility restorer (Rf3. However, the gene mapping of these minor QTLs and the molecular mechanism of the genetic modifications are still unclear. Using completely sterile and partially rescued plants of fertility instable line (FIL-B, we performed bulk segregant RNA-Seq and identified six potential associated genes in minor effect QTLs contributing to fertility instability. Analyses demonstrate that these potential associated genes may be involved in biological processes, such as floral organ differentiation and development regulation, energy metabolism and carbohydrates biosynthesis, which results in a partial anther exsertion and pollen fertility restoration in the partially rescued plants. The single nucleotide polymorphisms (SNPs identified in two potential associated genes were validated to be related to the fertility restoration phenotype by KASP marker assays. This novel knowledge contributes to the understanding of the molecular mechanism of the partial fertility restoration of CMS-S in maize and thus helps to guide the breeding programs.

  5. Identification and introgression of QTLs implicated in resistance to ...

    Indian Academy of Sciences (India)

    2015-12-08

    Dec 8, 2015 ... of polygenes which necessitated identification of quantitative-trait loci ... Genetic analysis of host resistance to SDM in maize ... Journal of Genetics, Vol. ..... The financial support for this research was provided by the Depart-.

  6. Maize production in mid hills of Nepal: from food to feed security

    OpenAIRE

    Krishna Prasad Timsina; Yuga Nath Ghimire; Jeevan Lamichhane

    2016-01-01

    This study was undertaken in 2016 to analyze the production and utilization of maize in Nepal. Sixty maize growers from Kavre and Lamjung districts were selected using purposive, cluster and simple random sampling techniques. Similarly, six feed industries and five maize experts from Chitwan district were also interviewed. Study shows 56% of the total areas were used for maize production and 50% of the maize areas were covered by hybrid maize. There was no practice of contract maize productio...

  7. The identification of aluminium-resistance genes provides opportunities for enhancing crop production on acid soils.

    Science.gov (United States)

    Ryan, P R; Tyerman, S D; Sasaki, T; Furuichi, T; Yamamoto, Y; Zhang, W H; Delhaize, E

    2011-01-01

    Acid soils restrict plant production around the world. One of the major limitations to plant growth on acid soils is the prevalence of soluble aluminium (Al(3+)) ions which can inhibit root growth at micromolar concentrations. Species that show a natural resistance to Al(3+) toxicity perform better on acid soils. Our understanding of the physiology of Al(3+) resistance in important crop plants has increased greatly over the past 20 years, largely due to the application of genetics and molecular biology. Fourteen genes from seven different species are known to contribute to Al(3+) tolerance and resistance and several additional candidates have been identified. Some of these genes account for genotypic variation within species and others do not. One mechanism of resistance which has now been identified in a range of species relies on the efflux of organic anions such as malate and citrate from roots. The genes controlling this trait are members of the ALMT and MATE families which encode membrane proteins that facilitate organic anion efflux across the plasma membrane. Identification of these and other resistance genes provides opportunities for enhancing the Al(3+) resistance of plants by marker-assisted breeding and through biotechnology. Most attempts to enhance Al(3+) resistance in plants with genetic engineering have targeted genes that are induced by Al(3+) stress or that are likely to increase organic anion efflux. In the latter case, studies have either enhanced organic anion synthesis or increased organic anion transport across the plasma membrane. Recent developments in this area are summarized and the structure-function of the TaALMT1 protein from wheat is discussed.

  8. The PTI1-like kinase ZmPti1a from maize (Zea mays L.) co-localizes with callose at the plasma membrane of pollen and facilitates a competitive advantage to the male gametophyte.

    Science.gov (United States)

    Herrmann, Markus M; Pinto, Sheena; Kluth, Jantjeline; Wienand, Udo; Lorbiecke, René

    2006-10-06

    The tomato kinase Pto confers resistance to bacterial speck disease caused by Pseudomonas syringae pv. tomato in a gene for gene manner. Upon recognition of specific avirulence factors the Pto kinase activates multiple signal transduction pathways culminating in induction of pathogen defense. The soluble cytoplasmic serine/threonine kinase Pti1 is one target of Pto phosphorylation and is involved in the hypersensitive response (HR) reaction. However, a clear role of Pti1 in plant pathogen resistance is uncertain. So far, no Pti1 homologues from monocotyledonous species have been studied. Here we report the identification and molecular analysis of four Pti1-like kinases from maize (ZmPti1a, -b, -c, -d). These kinase genes showed tissue-specific expression and their corresponding proteins were targeted to different cellular compartments. Sequence similarity, expression pattern and cellular localization of ZmPti1b suggested that this gene is a putative orthologue of Pti1 from tomato. In contrast, ZmPti1a was specifically expressed in pollen and sequestered to the plasma membrane, evidently owing to N-terminal modification by myristoylation and/or S-acylation. The ZmPti1a:GFP fusion protein was not evenly distributed at the pollen plasma membrane but accumulated as an annulus-like structure which co-localized with callose (1,3-beta-glucan) deposition. In addition, co-localization of ZmPti1a and callose was observed during stages of pollen mitosis I and pollen tube germination. Maize plants in which ZmPti1a expression was silenced by RNA interference (RNAi) produced pollen with decreased competitive ability. Hence, our data provide evidence that ZmPti1a plays an important part in a signalling pathway that accelerates pollen performance and male fitness. ZmPti1a from maize is involved in pollen-specific processes during the progamic phase of reproduction, probably in crucial signalling processes associated with regions of callose deposition. Pollen

  9. Vulnerability of Maize Yields to Droughts in Uganda

    Directory of Open Access Journals (Sweden)

    Terence Epule Epule

    2017-03-01

    Full Text Available Climate projections in Sub-Saharan Africa (SSA forecast an increase in the intensity and frequency of droughts with implications for maize production. While studies have examined how maize might be affected at the continental level, there have been few national or sub-national studies of vulnerability. We develop a vulnerability index that combines sensitivity, exposure and adaptive capacity and that integrates agroecological, climatic and socio-economic variables to evaluate the national and spatial pattern of maize yield vulnerability to droughts in Uganda. The results show that maize yields in the north of Uganda are more vulnerable to droughts than in the south and nationally. Adaptive capacity is higher in the south of the country than in the north. Maize yields also record higher levels of sensitivity and exposure in the north of Uganda than in the south. Latitudinally, it is observed that maize yields in Uganda tend to record higher levels of vulnerability, exposure and sensitivity towards higher latitudes, while in contrast, the adaptive capacity of maize yields is higher towards the lower latitudes. In addition to lower precipitation levels in the north of the country, these observations can also be explained by poor soil quality in most of the north and socio-economic proxies, such as, higher poverty and lower literacy rates in the north of Uganda.

  10. Contributions of Zea mays subspecies mexicana haplotypes to modern maize.

    Science.gov (United States)

    Yang, Ning; Xu, Xi-Wen; Wang, Rui-Ru; Peng, Wen-Lei; Cai, Lichun; Song, Jia-Ming; Li, Wenqiang; Luo, Xin; Niu, Luyao; Wang, Yuebin; Jin, Min; Chen, Lu; Luo, Jingyun; Deng, Min; Wang, Long; Pan, Qingchun; Liu, Feng; Jackson, David; Yang, Xiaohong; Chen, Ling-Ling; Yan, Jianbing

    2017-11-30

    Maize was domesticated from lowland teosinte (Zea mays ssp. parviglumis), but the contribution of highland teosinte (Zea mays ssp. mexicana, hereafter mexicana) to modern maize is not clear. Here, two genomes for Mo17 (a modern maize inbred) and mexicana are assembled using a meta-assembly strategy after sequencing of 10 lines derived from a maize-teosinte cross. Comparative analyses reveal a high level of diversity between Mo17, B73, and mexicana, including three Mb-size structural rearrangements. The maize spontaneous mutation rate is estimated to be 2.17 × 10 -8 ~3.87 × 10 -8 per site per generation with a nonrandom distribution across the genome. A higher deleterious mutation rate is observed in the pericentromeric regions, and might be caused by differences in recombination frequency. Over 10% of the maize genome shows evidence of introgression from the mexicana genome, suggesting that mexicana contributed to maize adaptation and improvement. Our data offer a rich resource for constructing the pan-genome of Zea mays and genetic improvement of modern maize varieties.

  11. Toxigenic potential of Fusarium graminearum isolated from maize of northwest Argentina

    Directory of Open Access Journals (Sweden)

    D.A. Sampietro

    2013-01-01

    Full Text Available Twenty six isolates of Fusarium graminearum from grains of maize hybrids harvested in ±west Argentina were grown on autoclaved rice grain to assess their ability to produce type B trichothecenes. Chemical analysis indicated that 38% of isolates were nivalenol (NIV producers only, 31% were major NIV producers with high DON(deoxynivalenol/NIV ratios, 8% were major DON producers with minor NIV production, and 23% were DON producers only. Isolates showed a high variability in their toxigenic potential which was not related to fungal biomass. The distribution of the different chemotypes as well as the high and the low trichothecene-producing Fusarium isolates could not be associated to a geographical origin. Our results confirmed for the first time that isolates of Fusarium graminearum from maize of northwest Argentina are able to produce DON and NIV. A substancial contamination with both NIV and DON is likely in maize from northwest Argentina. Their contents should be quantified in regional surveillances for mycotoxin contamination.

  12. Oven-drying reduces ruminal starch degradation in maize kernels

    NARCIS (Netherlands)

    Ali, M.; Cone, J.W.; Hendriks, W.H.; Struik, P.C.

    2014-01-01

    The degradation of starch largely determines the feeding value of maize (Zea mays L.) for dairy cows. Normally, maize kernels are dried and ground before chemical analysis and determining degradation characteristics, whereas cows eat and digest fresh material. Drying the moist maize kernels

  13. Creating molecular macrocycles for anion recognition

    Directory of Open Access Journals (Sweden)

    Amar H. Flood

    2016-03-01

    Full Text Available The creation and functionality of new classes of macrocycles that are shape persistent and can bind anions is described. The genesis of triazolophane macrocycles emerges out of activity surrounding 1,2,3-triazoles made using click chemistry; and the same triazoles are responsible for anion capture. Mistakes made and lessons learnt in anion recognition provide deeper understanding that, together with theory, now provides for computer-aided receptor design. The lessons are acted upon in the creation of two new macrocycles. First, cyanostars are larger and like to capture large anions. Second is tricarb, which also favors large anions but shows a propensity to self-assemble in an orderly and stable manner, laying a foundation for future designs of hierarchical nanostructures.

  14. Maize root lectins mediate the interaction with Herbaspirillum seropedicae via N-acetyl glucosamine residues of lipopolysaccharides.

    Directory of Open Access Journals (Sweden)

    Eduardo Balsanelli

    Full Text Available Herbaspirillum seropedicae is a plant growth-promoting diazotrophic betaproteobacterium which associates with important crops, such as maize, wheat, rice and sugar-cane. We have previously reported that intact lipopolysaccharide (LPS is required for H. seropedicae attachment and endophytic colonization of maize roots. In this study, we present evidence that the LPS biosynthesis gene waaL (codes for the O-antigen ligase is induced during rhizosphere colonization by H. seropedicae. Furthermore a waaL mutant strain lacking the O-antigen portion of the LPS is severely impaired in colonization. Since N-acetyl glucosamine inhibits H. seropedicae attachment to maize roots, lectin-like proteins from maize roots (MRLs were isolated and mass spectrometry (MS analysis showed that MRL-1 and MRL-2 correspond to maize proteins with a jacalin-like lectin domain, while MRL-3 contains a B-chain lectin domain. These proteins showed agglutination activity against wild type H. seropedicae, but failed to agglutinate the waaL mutant strain. The agglutination reaction was severely diminished in the presence of N-acetyl glucosamine. Moreover addition of the MRL proteins as competitors in H. seropedicae attachment assays decreased 80-fold the adhesion of the wild type to maize roots. The results suggest that N-acetyl glucosamine residues of the LPS O-antigen bind to maize root lectins, an essential step for efficient bacterial attachment and colonization.

  15. Maize root lectins mediate the interaction with Herbaspirillum seropedicae via N-acetyl glucosamine residues of lipopolysaccharides.

    Science.gov (United States)

    Balsanelli, Eduardo; Tuleski, Thalita Regina; de Baura, Valter Antonio; Yates, Marshall Geoffrey; Chubatsu, Leda Satie; Pedrosa, Fabio de Oliveira; de Souza, Emanuel Maltempi; Monteiro, Rose Adele

    2013-01-01

    Herbaspirillum seropedicae is a plant growth-promoting diazotrophic betaproteobacterium which associates with important crops, such as maize, wheat, rice and sugar-cane. We have previously reported that intact lipopolysaccharide (LPS) is required for H. seropedicae attachment and endophytic colonization of maize roots. In this study, we present evidence that the LPS biosynthesis gene waaL (codes for the O-antigen ligase) is induced during rhizosphere colonization by H. seropedicae. Furthermore a waaL mutant strain lacking the O-antigen portion of the LPS is severely impaired in colonization. Since N-acetyl glucosamine inhibits H. seropedicae attachment to maize roots, lectin-like proteins from maize roots (MRLs) were isolated and mass spectrometry (MS) analysis showed that MRL-1 and MRL-2 correspond to maize proteins with a jacalin-like lectin domain, while MRL-3 contains a B-chain lectin domain. These proteins showed agglutination activity against wild type H. seropedicae, but failed to agglutinate the waaL mutant strain. The agglutination reaction was severely diminished in the presence of N-acetyl glucosamine. Moreover addition of the MRL proteins as competitors in H. seropedicae attachment assays decreased 80-fold the adhesion of the wild type to maize roots. The results suggest that N-acetyl glucosamine residues of the LPS O-antigen bind to maize root lectins, an essential step for efficient bacterial attachment and colonization.

  16. Deciphering the role of NADPH oxidase in complex interactions between maize (Zea mays L.) genotypes and cereal aphids.

    Science.gov (United States)

    Sytykiewicz, Hubert

    2016-07-22

    Plant NADPH oxidases (NOXs) encompass a group of membrane-bound enzymes participating in formation of reactive oxygen species (ROS) under physiological conditions as well as in response to environmental stressors. The purpose of the survey was to unveil the role of NADPH oxidase in pro-oxidative responses of maize (Zea mays L.) seedling leaves exposed to cereal aphids' infestation. The impact of apteral females of bird cherry-oat aphid (Rhopalosiphum padi L.) and grain aphid (Sitobion avenae F.) feeding on expression levels of all four NADPH oxidase genes (rbohA, rbohB, rbohC, rbohD) and total activity of NOX enzyme in maize plants were investigated. In addition, inhibitory effect of diphenylene iodonium (DPI) pre-treatment on NOX activity and hydrogen peroxide content in aphid-stressed maize seedlings was studied. Leaf infestation biotests were accomplished on 14-day-old seedlings representing two aphid-resistant varieties (Ambrozja and Waza) and two aphid-susceptible ones (Tasty Sweet and Złota Karłowa). Insects' attack led to profound upregulation of rbohA and rbohD genes in tested host plants, lower elevations were noted in level of rbohB mRNA, whereas abundance of rbohC transcript was not significantly altered. It was uncovered aphid-induced enhancement of NOX activity in examined plants. Higher increases in expression of all investigated rboh genes and activity of NADPH oxidase occurred in tissues of more resistant maize cultivars than in susceptible ones. Furthermore, DPI treatment resulted in strong reduction of NOX activity and H2O2 accumulation in aphid-infested Z. mays plants, thus evidencing circumstantial role of the enzyme in insect-elicited ROS generation. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. Formation of interstellar anions

    Science.gov (United States)

    Senent, Maria Luisa

    2012-05-01

    Formation of interstellar anions: M.L. Senent. The recent detection of negative charged species in the ISM1 has instigated enthusiasm for anions in the astrophysical community2. Many of these species are new and entail characterization. How they are formed in astrophysical sources is a question of major relevance. The anion presence in ISM was first predicted theoretically on the basis of electron affinities and on the negative linear chain molecular stabilities. Although very early, they were considered in astrochemical models3-4, their discovery is so recent because their abundances seem to be relatively low. These have to be understood in terms of molecular stabilities, reaction probabilities and radiative and collisional excitations. Then, we present our theoretical work on even carbon chains type Cn and CnH (n=2,4,6) focused to the understanding of anion abundances. We use highly correlated ab initio methods. We performed spectroscopic studies of various isomers that can play important roles as intermediates5-8. In previous papers9-10, we compared C2H and C2H- collisional rates responsible for observed line intensities. Actually, we study hydrogen attachment (Cn +H → CnH and Cn- +H → CnH-) and associative detachment processes (Cn- +H → CnH +e-) for 2, 4 and 6 carbon atom chains11. [1] M.C.McCarthy, C.A.Gottlieb, H.Gupta, P.Thaddeus, Astrophys.J, 652, L141 (2006) [2] V.M.Bierbaum, J.Cernicharo, R.Bachiller, eds., 2011, pp 383-389. [3] A. Dalgarno, R.A. Mc Cray, Astrophys.J,, 181, 95 (1973) [4] E. Herbst E., Nature, 289, 656 (1981); [5] H.Massó, M.L.Senent, P.Rosmus, M.Hochlaf, J.Chem.Phys., 124, 234304 (2006) [6] M.L.Senent, M.Hochlaf, Astrophys. J. , 708, 1452(2010) [7] H.Massó, M.L.Senent, J.Phys.Chem.A, 113, 12404 (2009) [8] D. Hammoutene, M.Hochlaf, M.L.Senent, submitted. [9] A. Spielfiedel, N. Feautrier, F. Najar, D. ben Abdallah, F. Dayou, M.L. Senent, F. Lique, Mon.Not.R.Astron.Soc., 421, 1891 (2012) [10] F.Dumouchel, A, Spielfieldel , M

  18. Metabolic engineering of geranic acid in maize to achieve fungal resistance is compromised by novel glycosylation patterns

    NARCIS (Netherlands)

    Yang, T.; Stoopen, G.; Yalpani, N.; Vervoort, J.J.M.; Vos, de R.; Voster, A.; Verstappen, F.W.A.; Bouwmeester, H.J.; Jongsma, M.A.

    2011-01-01

    Many terpenoids are known to have antifungal properties and overexpression of these compounds in crops is a potential tool in disease control. In this study, 15 different mono- and sesquiterpenoids were tested in vitro against two major pathogenic fungi of maize (Zea mays), Colletotrichum

  19. Resistant starch and protein intake enhances fat oxidation and feelings of fullness in lean and overweight/obese women

    DEFF Research Database (Denmark)

    Gentile, Christopher L; Ward, Emery; Holst, Jens Juul

    2015-01-01

    and overweight/obese women. METHODS: Women of varying levels of adiposity consumed one of four pancake test meals in a single-blind, randomized crossover design: 1) waxy maize (control) starch (WMS); 2) waxy maize starch and whey protein (WMS+WP); 3) resistant starch (RS); or 4) RS and whey protein (RS...

  20. Assessing spatiotemporal variation of drought and its impact on maize yield in Northeast China

    Science.gov (United States)

    Guo, Enliang; Liu, Xingpeng; Zhang, Jiquan; Wang, Yongfang; Wang, Cailin; Wang, Rui; Li, Danjun

    2017-10-01

    In the context of global climate change, drought has become an important factor that affects the maize yield in China. To analyse the impact of drought on maize yield loss in Northeast China in current and future climate scenarios, the Composite Meteorological Drought Index (CI) is introduced to reconstruct the following drought indicators: drought accumulative days (DAD), drought accumulative intensity (DAI), and consecutive drought days (CDD). These three drought indicators are used to describe the three-dimensional characteristics of drought in this study. Sen's slope method and three-dimensional copula functions are adopted to analyse the variety of drought features, and Ensemble Empirical Mode Decomposition (EEMD) is used to analyse the variations in maize yield. A temporal assessment of the standardized yield residuals series (SYRS) of maize from 1961 to 2014 is conducted. A panel regression model is applied to demonstrate the drought impact on maize yield at various growth stages under the RCP4.5 scenario. The results show that the drought risk level for midwest Jilin Province, western Liaoning, and eastern Heilongjiang increase with global warming in the current scenario. The shorter three-dimensional joint return periods, 44-80 yr, were mainly located in western Jilin Province, Liaodong Peninsula, and northwestern Liaoning. Eastern Heilongjiang has a slightly longer joint return period of 80-100 yr. The SYRS shows a strong statistical correlation with drought indicator variations; drought-prone regions exhibit strong positive correlations. In comparison, excess precipitation regions show strong negative correlations with drought indicators in most growth stages. Drought indicators have a relatively strong association with SYRS at the milky-mature maize growth stage, and the occurrence of drought during this period primarily determines the maize yield changes in the future. Maize yield changes are -2.04%, -2.65% and -1.57% for Liaoning, Jilin, and

  1. Effect of organic fertilizers on maize production in Eastern Georgia

    Science.gov (United States)

    Jolokhava, Tamar; Kenchiashvili, Naira; Tarkhnishvili, Maia; Ghambashidze, Giorgi

    2016-04-01

    Maize remains to be the most important cereal crop in Georgia. Total area of arable land under cereal crops production equals to 184 thousands hectares (FAO statistical yearbook, 2014), from which maize takes the biggest share. Leading position of maize among other cereal crops is caused by its dual purpose as food and feed product. In Spite of a relatively high production of maize to other cereals there is still a high demand on it, especially as feed for animal husbandry. The same tendency is seen in organic production, where producers of livestock and poultry products require organically grown maize, the average yield of which is much less than those produced conventionally. Therefore, it is important to increase productivity of maize in organic farms. Current study aimed to improve maize yield using locally produced organic fertilizers and to compare them to the effect of mineral fertilizers. The study was carried out in Eastern Georgia under dry subtropical climate conditions on local hybrid of maize. This is the first attempt to use hybrid maize (developed with organic plant breeding method) in organic field trials in Georgia. The results shown, that grain yield from two different types of organic fertilizers reached 70% of the yields achieved with industrial mineral fertilizers. As on farm level differences between organic and conventional maize production are much severe, the results from the field trials seems to be promising for future improvement of organic cereal crop production.

  2. Intercropping maize with cassava or cowpea in Ghana | Ennin ...

    African Journals Online (AJOL)

    Maize/cassava and maize/cowpea intercrops were evaluated in southern Ghana, over a 5-year period to determine the optimum combination of component crop varieties and component plant population densities to optimize productivity of maize-based intercropping systems. Results indicated that some cowpea varieties ...

  3. Energy balance, costs and CO2 analysis of tillage technologies in maize cultivation

    International Nuclear Information System (INIS)

    Šarauskis, Egidijus; Buragienė, Sidona; Masilionytė, Laura; Romaneckas, Kęstutis; Avižienytė, Dovile; Sakalauskas, Antanas

    2014-01-01

    To achieve energy independence, Lithuania and other Baltic countries are searching for new ways to produce energy. Maize is a crop that is suitable for both food and forage, as well as for the production of bioenergy. The objective of this work was to assess the energy efficiency of maize cultivation technologies in different systems of reduced tillage. The experimental research and energy assessment was carried out for five different tillage systems: DP (deep ploughing), SP (), DC (deep cultivation), SC (shallow cultivation) and NT (no tillage). The assessment of the fuel inputs for these systems revealed that the greatest amount of diesel fuel (67.2 l ha −1 ) was used in the traditional DP system. The reduced tillage systems required 12–58% less fuel. Lower fuel consumption reduces the costs of technological operations and reduces CO 2 emissions, which are associated with the greenhouse effect. The agricultural machinery used in reduced tillage technologies emits 107–223 kg ha −1 of CO 2 gas into the environment, whereas DP emits 253 kg ha −1 of CO 2 . The energy analysis conducted in this study showed that the greatest total energy input (approximately 18.1 GJ ha −1 ) was associated with the conventional deep-ploughing tillage technology. The energy inputs associated with the reduced-tillage technologies, namely SP, DC and SC, ranged from 17.1 to 17.6 GJ ha −1 . The lowest energy input (16.2 GJ ha −1 ) was associated with the NT technology. Energy efficiency ratios for the various technologies were calculated as a function of the yield of maize grain and biomass. The best energy balance and the highest energy efficiency ratio (14.0) in maize cultivation was achieved with the NT technology. The energy efficiency ratios for DP, SP, DC and SC were 12.4, 13.4, 11.3 and 12.0, respectively. - Highlights: • Energetical and economic analysis of maize cultivation was done. • Reduced tillage technology reduces working time, fuel consumption

  4. Romanian maize

    DEFF Research Database (Denmark)

    Sauer, Johannes; Balint, Borbala

    This research aims at shedding empirical light on the relative efficiency of small-scale maize producers in Romania. Farmers in transition countries still face heavily distorted price systems resulting from imperfect market conditions and socioeconomic and institutional constraints. To capture...

  5. ProFITS of maize: a database of protein families involved in the transduction of signalling in the maize genome

    Directory of Open Access Journals (Sweden)

    Zhang Zhenhai

    2010-10-01

    Full Text Available Abstract Background Maize (Zea mays ssp. mays L. is an important model for plant basic and applied research. In 2009, the B73 maize genome sequencing made a great step forward, using clone by clone strategy; however, functional annotation and gene classification of the maize genome are still limited. Thus, a well-annotated datasets and informative database will be important for further research discoveries. Signal transduction is a fundamental biological process in living cells, and many protein families participate in this process in sensing, amplifying and responding to various extracellular or internal stimuli. Therefore, it is a good starting point to integrate information on the maize functional genes involved in signal transduction. Results Here we introduce a comprehensive database 'ProFITS' (Protein Families Involved in the Transduction of Signalling, which endeavours to identify and classify protein kinases/phosphatases, transcription factors and ubiquitin-proteasome-system related genes in the B73 maize genome. Users can explore gene models, corresponding transcripts and FLcDNAs using the three abovementioned protein hierarchical categories, and visualize them using an AJAX-based genome browser (JBrowse or Generic Genome Browser (GBrowse. Functional annotations such as GO annotation, protein signatures, protein best-hits in the Arabidopsis and rice genome are provided. In addition, pre-calculated transcription factor binding sites of each gene are generated and mutant information is incorporated into ProFITS. In short, ProFITS provides a user-friendly web interface for studies in signal transduction process in maize. Conclusion ProFITS, which utilizes both the B73 maize genome and full length cDNA (FLcDNA datasets, provides users a comprehensive platform of maize annotation with specific focus on the categorization of families involved in the signal transduction process. ProFITS is designed as a user-friendly web interface and it is

  6. Anion concurrence and anion selectivity in the sorption of radionuclides by organotones

    International Nuclear Information System (INIS)

    Behnsen, Julia G.

    2007-01-01

    Some long-lived and radiologically important nuclear fission products, such as I-129 (half-life t 1/2 = 1,6 . 10 7 a), Tc-99 (t 1/2 = 2,1 . 10 5 a), and Se-79 (t 1/2 = 6,5 . 10 4 a) are anionic in aqueous environments. This study focuses on the adsorption of such anions to organoclays and the understanding of the selectivity of the process. The organoclays used in this study were prepared from a bentonite (MX-80) and a vermiculite clay, and the cationic surfactants hexadcylpyridium, hexadecyltrimethylammonium, and benzethonium. Surfactant adsorption to the bentonite exceeds the cation exchange capacity of the clay, with the surplus positive charge being balanced by the co-adsorption of chloride. The interlayer distance of the bentonites is increased sufficiently to contain bi- and pseudotrimolecular structures of the surfactants. Adsorption experiments were carried out using the batch technique. Anion adsorption of iodide, perrhenate, selenite, nitrate, and sulphate is mainly due to ion exchange with chloride. As an additional adsorption mechanism, the incorporation of inorganic ion pairs into the interlayer space of the clay is proposed as a result of experiments showing differences in the adsorption levels of sodium and potassium iodide. Anion adsorption results show a clear selectivity of the organoclays, with the affinity sequence being: ReO - 4 > I - > NO - 3 > Cl - > SO 2- 4 > SeO 2- 3 . This sequence corresponds to the sequence of increasing hydration energies of the anions, thus selectivity could be due to the process of minimization of free energy of the system. (orig.)

  7. Facilitation of phosphorus uptake in maize plants by mycorrhizosphere bacteria

    DEFF Research Database (Denmark)

    Battini, Fabio; Grønlund, Mette; Agnolucci, Monica

    2017-01-01

    availability of soil P. This study investigated whether biofertilizers and bioenhancers, such as arbuscular mycorrhizal fungi (AMF) and their associated bacteria could enhance growth and P uptake in maize. Plants were grown with or without mycorrhizas in compartmented pots with radioactive P tracers and were...

  8. Confirming QTL for aflatoxin resistance from Mp313E in different genetic backgrounds

    Science.gov (United States)

    The fungus Aspergillus flavus (Link:Fr) causes ear rot of maize (Zea mays L.) and produces the toxic metabolic product aflatoxin. One particularly effective method to control the fungus is via host plant resistance, but while several resistant breeding lines have been identified, transferring the r...

  9. Maize flour fortification in Africa: markets, feasibility, coverage, and costs.

    Science.gov (United States)

    Fiedler, John L; Afidra, Ronald; Mugambi, Gladys; Tehinse, John; Kabaghe, Gladys; Zulu, Rodah; Lividini, Keith; Smitz, Marc-Francois; Jallier, Vincent; Guyondet, Christophe; Bermudez, Odilia

    2014-04-01

    The economic feasibility of maize flour and maize meal fortification in Kenya, Uganda, and Zambia is assessed using information about the maize milling industry, households' purchases and consumption levels of maize flour, and the incremental cost and estimated price impacts of fortification. Premix costs comprise the overwhelming share of incremental fortification costs and vary by 50% in Kenya and by more than 100% across the three countries. The estimated incremental cost of maize flour fortification per metric ton varies from $3.19 in Zambia to $4.41 in Uganda. Assuming all incremental costs are passed onto the consumer, fortification in Zambia would result in at most a 0.9% increase in the price of maize flour, and would increase annual outlays of the average maize flour-consuming household by 0.2%. The increases for Kenyans and Ugandans would be even less. Although the coverage of maize flour fortification is not likely to be as high as some advocates have predicted, fortification is economically feasible, and would reduce deficiencies of multiple micronutrients, which are significant public health problems in each of these countries. © 2013 New York Academy of Sciences.

  10. Finding Relational Associations in HIV Resistance Mutation Data

    Science.gov (United States)

    Richter, Lothar; Augustin, Regina; Kramer, Stefan

    HIV therapy optimization is a hard task due to rapidly evolving mutations leading to drug resistance. Over the past five years, several machine learning approaches have been developed for decision support, mostly to predict therapy failure from the genotypic sequence of viral proteins and additional factors. In this paper, we define a relational representation for an important part of the data, namely the sequences of a viral protein (reverse transcriptase), their mutations, and the drug resistance(s) associated with those mutations. The data were retrieved from the Los Alamos National Laboratories' (LANL) HIV databases. In contrast to existing work in this area, we do not aim directly for predictive modeling, but take one step back and apply descriptive mining methods to develop a better understanding of the correlations and associations between mutations and resistances. In our particular application, we use the Warmr algorithm to detect non-trivial patterns connecting mutations and resistances. Our findings suggest that well-known facts can be rediscovered, but also hint at the potential of discovering yet unknown associations.

  11. Lack of Detectable Allergenicity in Genetically Modified Maize Containing “Cry” Proteins as Compared to Native Maize Based on In Silico & In Vitro Analysis

    Science.gov (United States)

    Mathur, Chandni; Kathuria, Pooran C.; Dahiya, Pushpa; Singh, Anand B.

    2015-01-01

    Background Genetically modified, (GM) crops with potential allergens must be evaluated for safety and endogenous IgE binding pattern compared to native variety, prior to market release. Objective To compare endogenous IgE binding proteins of three GM maize seeds containing Cry 1Ab,1Ac,1C transgenic proteins with non GM maize. Methods An integrated approach of in silico & in vitro methods was employed. Cry proteins were tested for presence of allergen sequence by FASTA in allergen databases. Biochemical assays for maize extracts were performed. Specific IgE (sIgE) and Immunoblot using food sensitized patients sera (n = 39) to non GM and GM maize antigens was performed. Results In silico approaches, confirmed for non sequence similarity of stated transgenic proteins in allergen databases. An insignificant (p> 0.05) variation in protein content between GM and non GM maize was observed. Simulated Gastric Fluid (SGF) revealed reduced number of stable protein fractions in GM then non GM maize which might be due to shift of constituent protein expression. Specific IgE values from patients showed insignificant difference in non GM and GM maize extracts. Five maize sensitized cases, recognized same 7 protein fractions of 88-28 kD as IgE bindng in both GM and non-GM maize, signifying absence of variation. Four of the reported IgE binding proteins were also found to be stable by SGF. Conclusion Cry proteins did not indicate any significant similarity of >35% in allergen databases. Immunoassays also did not identify appreciable differences in endogenous IgE binding in GM and non GM maize. PMID:25706412

  12. The response of maize production in Kenya to economic incentives

    Directory of Open Access Journals (Sweden)

    Onono, P.A.,

    2013-06-01

    Full Text Available Agricultural development policy in Kenya has emphasised the use of incentives towards increased production and therefore self-sufficiency in maize which is a basic staple for most households. The channels used to provide incentives to maize farmers over the years include setting higher producer prices; subsidisation of inputs; provision of agricultural credit, research and extension services; construction and maintenance of roads, development of irrigation and water systems; legislative, institutional and macroeconomic reforms. Despite these efforts outputof maize has remained below domestic requirements in most years and the country continues to rely on imports to meet the deficits. Studies have assessed the responsiveness of maize to output price and reported inelastic responses and have recommended policies targeting non-price incentives to complement prices for the required increased production of maize. The studies, however, did not analyse the influence of the non-price incentives on the production of the crop. The findings of those studies are therefore deficient in explaining the relative importance of different non-price incentives and how they complement prices in influencing maize production in Kenya. This study investigated the response of maize production to both price and non-price incentives. The aim of this study was to ascertain the relative importance of non-price factors in influencing production of the crops as well as complementarity between price and non-price incentives. The findings show that maize production responds positively to its output price, development expenditures in agriculture, maize sales to marketing boards, growth in per capita GDP, liberalisation and governance reforms. However, maize production responds negatively to fertiliser price and unfavourable weather conditions. The response of maize output to its price is lower with rising inflation and grain market liberalisation.

  13. Significant characteristics of the new maize hybrid Rubin-7

    Directory of Open Access Journals (Sweden)

    Jeličić Zora

    2003-01-01

    Full Text Available The Rubin-7 maize hybrid belongs to the FAO 700 maturity group. It is characterized by high yield potential for kernels, which was proven during investigations by the Committee for Species. During the three year monitoring period, from 1999 to 2001, the average yield of kernel was 9.412 t/ha which is 5% above the ZP 704 standard, and was highly statistically significant. Resistance to disease was high for Ustilago maydis 0.49, Fusarium spp. 0.13, and Exerohilum turcicum 1.25. Tolerance against Ostrinia nubilalis is 3-33. All of the above parameters and the agreeable phenotype of this hybrid indicate the value of Rubin-7. .

  14. PROFITABILITY AND MARKETING EFFICIENCY OF MAIZE IN KWANDE LOCAL GOVERNMENT AREA OF BENUE STATE, NIGERIA

    Directory of Open Access Journals (Sweden)

    Zacharias Ternenge Nyiatagher

    2015-12-01

    Full Text Available The paper presents profi tability and marketing effi - ciency of maize in Kwande Local Government Area of Benue State, Nigeria. Stratifi ed random sampling was used to select three hundred (300 maize marketers comprising producers (210, wholesalers (32 and retailers (58 in eight (8 major markets in the study area. Primary data were collected using structured questionnaires. Data were analyzed using descriptive statistics, marketing margin and marketing effi ciency. It was found that maize marketing in the study area was dominated by males (64.7% and young people (55.0% who are energetic enough to withstand the stress involved in the business. The marketing margin of an average maize marketer in the study area was N2,012.00 per 100kg and the percentage marketing margin was 37.2%. This showed that maize marketing in the study area was profi table and 100% retail price paid by the fi nal consumer resulted in farm-to-retail price spread or marketing margin of 37.2%. The marketing effi ciency (0.28 of mai ze in the study area indicated that the marketers were ineffi cient in maize business. It was recommended that government, non-governmental organizations and the rural populace should strive hard to improve the transportation network and the marketers should belong to marketing associations so that they can collectively access loans from rural banking institutions

  15. MaizeGDB: enabling access to basic, translational, and applied research information

    Science.gov (United States)

    MaizeGDB is the Maize Genetics and Genomics Database (available online at http://www.maizegdb.org). The MaizeGDB project is not simply an online database and website but rather an information service to maize researchers that supports customized data access and analysis needs to individual research...

  16. A model-based approach to preplanting risk assessment for gray leaf spot of maize.

    Science.gov (United States)

    Paul, P A; Munkvold, G P

    2004-12-01

    ABSTRACT Risk assessment models for gray leaf spot of maize, caused by Cercospora zeae-maydis, were developed using preplanting site and maize genotype data as predictors. Disease severity at the dough/dent plant growth stage was categorized into classes and used as the response variable. Logistic regression and classification and regression tree (CART) modeling approaches were used to predict severity classes as a function of planting date (PD), amount of maize soil surface residue (SR), cropping sequence, genotype maturity and gray leaf spot resistance (GLSR) ratings, and longitude (LON). Models were development using 332 cases collected between 1998 and 2001. Thirty cases collected in 2002 were used to validate the models. Preplanting data showed a strong relationship with late-season gray leaf spot severity classes. The most important predictors were SR, PD, GLSR, and LON. Logistic regression models correctly classified 60 to 70% of the validation cases, whereas the CART models correctly classified 57 to 77% of these cases. Cases misclassified by the CART models were mostly due to overestimation, whereas the logistic regression models tended to misclassify cases by underestimation. Both the CART and logistic regression models have potential as management decision-making tools. Early quantitative assessment of gray leaf spot risk would allow for more sound management decisions being made when warranted.

  17. Changes in the transcriptomic profiles of maize roots in response to iron-deficiency stress.

    Science.gov (United States)

    Li, Yan; Wang, Nian; Zhao, Fengtao; Song, Xuejiao; Yin, Zhaohua; Huang, Rong; Zhang, Chunqing

    2014-07-01

    Plants are often subjected to iron (Fe)-deficiency stress because of its low solubility. Plants have evolved two distinct strategies to solubilize and transport Fe to acclimate to this abiotic stress condition. Transcriptomic profiling analysis was performed using Illumina digital gene expression to understand the mechanism underlying resistance responses of roots to Fe starvation in maize, an important Strategy II plant. A total of 3,427, 4,069, 4,881, and 2,610 genes had significantly changed expression levels after Fe-deficiency treatments of 1, 2, 4 or 7 days, respectively. Genes involved in 2'-deoxymugineic acid (DMA) synthesis, secretion, and Fe(III)-DMA uptake were significantly induced. Many genes related to plant hormones, protein kinases, and protein phosphatases responded to Fe-deficiency stress, suggesting their regulatory roles in response to the Fe-deficiency stress. Functional annotation clustering analysis, using the Database for Annotation, Visualization and Integrated Discovery, revealed maize root responses to Fe starvation. This resulted in 38 functional annotation clusters: 25 for up-regulated genes, and 13 for down-regulated ones. These included genes encoding enzymes involved in the metabolism of carboxylic acids, isoprenoids and aromatic compounds, transporters, and stress response proteins. Our work provides integrated information for understanding maize response to Fe-deficiency stress.

  18. Simultaneous anion and cation mobility in polypyrrole

    DEFF Research Database (Denmark)

    Skaarup, Steen; Bay, Lasse; Vidanapathirana, K.

    2003-01-01

    and the expulsion of anions; a broad anodic peak centered at ca. - 0.5 V representing the expulsion of cations; and a second broad peak at +0.2 to +0.5 V corresponding to anions being inserted. Although the motion of cations is the most important, as expected, there is a significant anion contribution, thereby...... complicating reproducibility when employing PPy(DBS) polymers as actuators. When the cation is doubly charged, it enters the film less readily, and anions dominate the mobility. Using a large and bulky cation switches the mechanism to apparently total anion motion. The changes in area of the three peaks...

  19. "Omics" of maize stress response for sustainable food production: opportunities and challenges.

    Science.gov (United States)

    Gong, Fangping; Yang, Le; Tai, Fuju; Hu, Xiuli; Wang, Wei

    2014-12-01

    Maize originated in the highlands of Mexico approximately 8700 years ago and is one of the most commonly grown cereal crops worldwide, followed by wheat and rice. Abiotic stresses (primarily drought, salinity, and high and low temperatures), together with biotic stresses (primarily fungi, viruses, and pests), negatively affect maize growth, development, and eventually production. To understand the response of maize to abiotic and biotic stresses and its mechanism of stress tolerance, high-throughput omics approaches have been used in maize stress studies. Integrated omics approaches are crucial for dissecting the temporal and spatial system-level changes that occur in maize under various stresses. In this comprehensive analysis, we review the primary types of stresses that threaten sustainable maize production; underscore the recent advances in maize stress omics, especially proteomics; and discuss the opportunities, challenges, and future directions of maize stress omics, with a view to sustainable food production. The knowledge gained from studying maize stress omics is instrumental for improving maize to cope with various stresses and to meet the food demands of the exponentially growing global population. Omics systems science offers actionable potential solutions for sustainable food production, and we present maize as a notable case study.

  20. Mixed cropping of groundnuts and maize in East Java

    NARCIS (Netherlands)

    Hoof, van W.C.H.

    1987-01-01

    Mixed cropping of groundnuts and maize in East Java was studied by means of a survey of farming practice and by field experiments. The influence of different sowing times and plant density of maize on the development and yield of groundnuts and maize were the main topics in this thesis. Plant

  1. Maize and the Malnutrition Conundrum in South Africa | BOOYENS ...

    African Journals Online (AJOL)

    In this paper, the author gives an overview of the factors leading to maize becoming a staple food among black people in South Africa. The purported relationship between maize consumption and malnutrition, proposals as well as experimental and practical efforts to correct the dietary deficiencies of maize are briefly ...

  2. EFFECT OF MAIZE INTERCROP PLANT DENSITIES ON YIELD ...

    African Journals Online (AJOL)

    ACSS

    protein maize (Zea mays L.) in combating vitamin A and protein malnutrition, small land holdings by rural poor farmers still ... A cet effet, l'association des cultures doublée d'une densité optimale des plants dans les systems ..... their foliar area to lessen water loss. Also ..... Valenzuela, H.R., O'Hair, S.K. and Schaffer, B. 1991 ...

  3. Graphene-coated polymeric anion exchangers for ion chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Kai; Cao, Minyi; Lou, Chaoyan [Department of Chemistry, Xixi Campus, Zhejiang University, Hangzhou 310028 (China); Wu, Shuchao, E-mail: wushch2002@163.com [Zhejiang Institute of Geology and Mineral Resources, Hangzhou 310007 (China); Zhang, Peimin [Department of Chemistry, Xixi Campus, Zhejiang University, Hangzhou 310028 (China); Zhi, Mingyu [Hangzhou Vocational & Technical College, Hangzhou, 310018 (China); Zhu, Yan, E-mail: zhuyan@zju.edu.cn [Department of Chemistry, Xixi Campus, Zhejiang University, Hangzhou 310028 (China)

    2017-06-01

    Carbonaceous stationary phases have gained much attention for their peculiar selectivity and robustness. Herein we report the fabrication and application of a graphene-coated polymeric stationary phase for anion exchange chromatography. The graphene-coated particles were fabricated by a facile evaporation-reduction method. These hydrophilic particles were proven appropriate substrates for grafting of hyperbranched condensation polymers (HBCPs) to make pellicular anion exchangers. The new phase was characterized by zeta potentials, Fourier transform infrared spectroscopy, thermogravimetry and scanning electron microscope. Frontal displacement chromatography showed that the capacities of the anion exchangers were tuned by both graphene amount and HBCPs layer count. The chromatographic performance of graphene-coated anion exchangers was demonstrated with separation of inorganic anions, organic acids, carbohydrates and amino acids. Good reproducibility was obtained by consecutive injections, indicating high chemical stability of the coating. - Highlights: • Graphene-coated polymeric particles were fabricated by a facile method. • Hyperbranched condensation polymers (HBCPs) were grafted from graphene-coated particles to make anion exchangers. • Graphene amount and HBCPs layer count had significant effects on the anion exchange capacities. • Separation of diverse anionic analytes on the anion exchangers was demonstrated. • The prepared anion exchangers exhibited high stability.

  4. Fumonisins in conventional and transgenic, insect-resistant maize intended for fuel ethanol production: implications for fermentation efficiency and DDGS co-product quality.

    Science.gov (United States)

    Bowers, Erin L; Munkvold, Gary P

    2014-09-22

    Mycotoxins in maize grain intended for ethanol production are enriched in co-product dried distiller's grains and solubles (DDGS) and may be detrimental to yeast in fermentation. This study was conducted to examine the magnitude of fumonisin enrichment in DDGS and to analyze the impacts of insect injury, Fusarium ear rot severity, and fumonisin contamination on final ethanol yield. Samples of naturally-contaminated grain (0 to 35 mg/kg fumonisins) from field trials conducted in 2008-2011 were fermented and DDGS collected and analyzed for fumonisin content. Ethanol yield (determined gravimetrically) was unaffected by fumonisins in the range occurring in this study, and was not correlated with insect injury or Fusarium ear rot severity. Ethanol production was unaffected in fumonisin B1-spiked grain with concentrations from 0 to 37 mg/kg. Bacillus thuringiensis (Bt) maize often has reduced fumonisins due to its protection from insect injury and subsequent fungal infection. DDGS derived from Bt and non-Bt maize averaged 2.04 mg/kg and 8.25 mg/kg fumonisins, respectively. Fumonisins were enriched by 3.0× for 50 out of 57 hybrid × insect infestation treatment combinations; those seven that differed were fumonisin enrichment in DDGS, with measurements traceable to individual samples. Under significant insect pest pressures, DDGS derived from Bt maize hybrids were consistently lower in fumonisins than DDGS derived from non-Bt hybrids.

  5. Gibberellins Promote Brassinosteroids Action and Both Increase Heterosis for Plant Height in Maize (Zea mays L.

    Directory of Open Access Journals (Sweden)

    Songlin Hu

    2017-06-01

    Full Text Available Brassinosteroids (BRs and Gibberellins (GAs are two classes of plant hormones affecting plant height (PHT. Thus, manipulation of BR and GA levels or signaling enables optimization of crop grain and biomass yields. We established backcross (BC families, selected for increased PHT, in two elite maize inbred backgrounds. Various exotic accessions used in the germplasm enhancement in maize project served as donors. BC1-derived doubled haploid lines in the same two elite maize inbred backgrounds established without selection for plant height were included for comparison. We conducted genome-wide association studies to explore the genetic control of PHT by BR and GA. In addition, we used BR and GA inhibitors to compare the relationship between PHT, BR, and GA in inbred lines and heterozygotes from a physiological and biological perspective. A total of 73 genomic loci were discovered to be associated with PHT, with seven co-localized with GA, and two co-localized with BR candidate genes. PHT determined in field trials was significantly correlated with seedling stage BR and GA inhibitor responses. However, this observation was only true for maize heterozygotes, not for inbred lines. Path analysis results suggest that heterozygosity increases GA levels, which in turn promote BR levels. Thus, at least part of heterosis for PHT in maize can be explained by increased GA and BR levels, and seedling stage hormone inhibitor response is promising to predict heterosis for PHT.

  6. Testing pollen of single and stacked insect-resistant Bt-maize on in vitro reared honey bee larvae.

    Science.gov (United States)

    Hendriksma, Harmen P; Härtel, Stephan; Steffan-Dewenter, Ingolf

    2011-01-01

    The ecologically and economic important honey bee (Apis mellifera) is a key non-target arthropod species in environmental risk assessment (ERA) of genetically modified (GM) crops. Honey bee larvae are directly exposed to transgenic products by the consumption of GM pollen. But most ERA studies only consider responses of adult bees, although Bt-proteins primarily affect the larval phases of target organisms. We adopted an in vitro larvae rearing system, to assess lethal and sublethal effects of Bt-pollen consumption in a standardized eco-toxicological bioassay. The effects of pollen from two Bt-maize cultivars, one expressing a single and the other a total of three Bt-proteins, on the survival and prepupae weight of honey bee larvae were analyzed. The control treatments included pollen from three non-transgenic maize varieties and of Heliconia rostrata. Three days old larvae were fed the realistic exposure dose of 2 mg pollen within the semi-artificial diet. The larvae were monitored over 120 h, until the prepupal stage, where larvae terminate feeding and growing. Neither single nor stacked Bt-maize pollen showed an adverse effect on larval survival and the prepupal weight. In contrast, feeding of H. rostrata pollen caused significant toxic effects. The results of this study indicate that pollen of the tested Bt-varieties does not harm the development of in vitro reared A. mellifera larvae. To sustain the ecosystem service of pollination, Bt-impact on A. mellifera should always be a crucial part of regulatory biosafety assessments. We suggest that our approach of feeding GM pollen on in vitro reared honey bee larvae is well suited of becoming a standard bioassay in regulatory risk assessments schemes of GM crops.

  7. Flavone-rich maize: An opportunity to improve the nutritional value of an important commodity crop

    Directory of Open Access Journals (Sweden)

    Maria Isabel Casas

    2014-09-01

    Full Text Available Agricultural outputs have resulted in food production continuously expanding. Satisfying the needs of a fast growing human population, higher yields, more efficient food processing, and food esthetic value, resulted in crop varieties with higher caloric intake but lacking many phytochemicals important for plant protection and adequate human nutrition. The increasing incidence of chronic diseases such as obesity, diabetes and cardiovascular diseases, combined with social disparity worldwide prompted the interest in developing enhanced crops that can simultaneously address the two sides of the current malnutrition sword, increasing yield while providing added nutritional value. Flavones, phytochemicals associated with the beneficial effects of the Mediterranean diet, have potent anti-inflammatory and anti-carcinogenic activities. However, many Mediterranean diet-associated vegetables are inaccessible, or lowly consumed, in many parts of the world. Maize is the most widely grown cereal crop, yet most lines used for hybrid maize production lack flavones. As a first step towards a sustainable strategy to increasing the nutritional value of maize-based diets, we investigated the accumulation and chemical properties of flavones in maize seeds of defined genotypes. We show that the pericarps of the P1-rr genotype accumulate flavones at levels comparable to those present in some flavone-rich vegetables, and are mostly present in their C- and O-glycosylated forms. Some of these glycosides can be readily converted into the corresponding more active health beneficial aglycones during food processing. Our results provide evidence that nutritionally beneficial flavones could be re-introduced into elite lines to increase the dietary benefits of maize.

  8. Photosynthesis and chlorophyll fluorescence reaction to different shade stresses of weak light sensitive maize

    International Nuclear Information System (INIS)

    Wang, J.; Li, F.; Shi, Z.; Huang, H.; Jia, S.

    2017-01-01

    A split-plot experimental study was conducted to evaluate the effect of different shade stresses on photosynthesis and chlorophyll fluorescence of maize leaves.The experiment was designed on the south farm of Special Corn Institute, Shenyang Agricultural University, China.Data was collected from the day maize tasseled (Jul. 21) to the beginning of grouting (Aug.12 ) under 18%, 28%, 38%, 60%, and 75% shade stress to determine indexes such as photosynthesis and chlorophyll fluorescence after 15 days of shade treatment. Pairs of near-isogenic lines (NILs) of Shennong 98A (a barren stalk inbred line) and Shennong 98B (an un-barren stalk inbred line) were used as experimental materials to further reveal photosynthetic mechanisms of weak light sensitive maize when exposed to weak light conditions. Thus, a foundation was established for high density-resistant (shade resistant) corn breeding,while identifying weak light sensitive varieties. After shading treatment, chlorophyll a and total chlorophyll content of both varieties increased, chlorophyll b content first increased, followed by a decrease, while the net photosynthetic rate and stomatal conductance showed a gradually decreasing trend. The changing trends of photochemical quenching coefficient(qp) and effective quantum yield of PSII photochemistry (FPSII)were similar, FPSII and qP increased significantly as shading stress increased from 18% to 38%;however, FPSII and qP declined significantly under 60% and 75% shading stresses. The changing trend of NPQ was opposite to FPSII and qP. A comparison of both inbred lines showed that photosynthesis and chlorophyll fluorescence characteristics of Shennong 98B were superior to Shennong 98A. This study revealed the relationships between weak light sensitive lines and shade intensities by comparing differences in photosynthesis and chlorophyll fluorescence parameters. (author)

  9. Making better maize plants for sustainable grain production in a changing climate.

    Science.gov (United States)

    Gong, Fangping; Wu, Xiaolin; Zhang, Huiyong; Chen, Yanhui; Wang, Wei

    2015-01-01

    Achieving grain supply security with limited arable land is a major challenge in the twenty-first century, owing to the changing climate and increasing global population. Maize plays an increasingly vital role in global grain production. As a C4 plant, maize has a high yield potential. Maize is predicted to become the number one cereal in the world by 2020. However, maize production has plateaued in many countries, and hybrid and production technologies have been fully exploited. Thus, there is an urgent need to shape maize traits and architectures for increased stress tolerance and higher yield in a changing climate. Recent achievements in genomics, proteomics, and metabolomics have provided an unprecedented opportunity to make better maize. In this paper, we discuss the current challenges and potential of maize production, particularly in China. We also highlight the need for enhancing maize tolerance to drought and heat waves, summarize the elite shoot and root traits and phenotypes, and propose an ideotype for sustainable maize production in a changing climate. This will facilitate targeted maize improvement through a conventional breeding program combined with molecular techniques.

  10. Effect of multiple metal resistant bacteria from contaminated lake sediments on metal accumulation and plant growth

    International Nuclear Information System (INIS)

    Li, Kefeng; Ramakrishna, Wusirika

    2011-01-01

    Naturally occurring bacteria play an important role in bioremediation of heavy metal pollutants in soil and wastewater. This study identified high levels of resistance to zinc, cesium, lead, arsenate and mercury in eight copper resistant Pseudomonas strains previously isolated from Torch Lake sediment. These strains showed variable susceptibility to different antibiotics. Furthermore, these metal resistant strains were capable of bioaccumulation of multiple metals and solubilization of copper. Bacterial strains TLC 3-3.5-1 and TLC 6-6.5-1 showed high bioaccumulation ability of Zn (up to 15.9 mg/g dry cell) and Pb (80.7 mg/g dry cell), respectively. All the strains produced plant growth promoting indole-3-acetic acid (IAA), iron chelating siderophore and solubilized mineral phosphate and metals. The effect of bacterial inoculation on plant growth and copper uptake by maize (Zea mays) and sunflower (Helianthus annuus) was investigated using one of the isolates (Pseudomonas sp. TLC 6-6.5-4) with higher IAA production and phosphate and metal soubilization, which resulted in a significant increase in copper accumulation in maize and sunflower, and an increase in the total biomass of maize. The multiple metal-resistant bacterial isolates characterized in our study have potential applications for remediation of metal contaminated soils in combination with plants and metal contaminated water.

  11. Effect of multiple metal resistant bacteria from contaminated lake sediments on metal accumulation and plant growth

    Energy Technology Data Exchange (ETDEWEB)

    Li, Kefeng [Department of Biological Sciences, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931 (United States); Ramakrishna, Wusirika, E-mail: wusirika@mtu.edu [Department of Biological Sciences, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931 (United States)

    2011-05-15

    Naturally occurring bacteria play an important role in bioremediation of heavy metal pollutants in soil and wastewater. This study identified high levels of resistance to zinc, cesium, lead, arsenate and mercury in eight copper resistant Pseudomonas strains previously isolated from Torch Lake sediment. These strains showed variable susceptibility to different antibiotics. Furthermore, these metal resistant strains were capable of bioaccumulation of multiple metals and solubilization of copper. Bacterial strains TLC 3-3.5-1 and TLC 6-6.5-1 showed high bioaccumulation ability of Zn (up to 15.9 mg/g dry cell) and Pb (80.7 mg/g dry cell), respectively. All the strains produced plant growth promoting indole-3-acetic acid (IAA), iron chelating siderophore and solubilized mineral phosphate and metals. The effect of bacterial inoculation on plant growth and copper uptake by maize (Zea mays) and sunflower (Helianthus annuus) was investigated using one of the isolates (Pseudomonas sp. TLC 6-6.5-4) with higher IAA production and phosphate and metal soubilization, which resulted in a significant increase in copper accumulation in maize and sunflower, and an increase in the total biomass of maize. The multiple metal-resistant bacterial isolates characterized in our study have potential applications for remediation of metal contaminated soils in combination with plants and metal contaminated water.

  12. Extraction and characterization of natural cellulose fibers from maize tassel

    CSIR Research Space (South Africa)

    Maepa, CE

    2015-04-01

    Full Text Available This article reports on the extraction and characterization of novel natural cellulose fibers obtained from the maize (tassel) plant. Cellulose was extracted from the agricultural residue (waste biomaterial) of maize tassel. The maize tassel fibers...

  13. Usage of γ-ray treatment for productivity increasing of maize

    International Nuclear Information System (INIS)

    Ilieva, V.; Dimov, K.

    2003-01-01

    The aim of this study is to determine the influence of γ irradiation on phosphorus nutrition and maize productivity increasing. The vegetation experiment with irradiated and non-irradiated maize seeds in controlled conditions (moisture and temperature) for determination of phosphorus and phosphorus-gypsum absorption was carried out. The influence of γ irradiation on maize growth, export of mineral elements in maize, phosphorus fertilizing and dry biomass of maize plants are presented. The effect of the moisture of γ irradiated maize seeds (sort 'Knezha' - 3L - 621) on dry substance and yield of green mass is also discussed. Based on the presented experimental data the following conclusion have been made: the maize seeds (sort 'Knezha, hybrid H-708) simulation is useful; in all variants of phosphorus-gypsum absorption the increasing of plant mass yield (absolutely dry) is observed; the absorbed phosphates reserve is enhanced twice; the efficiency of 32 P use in stimulated seeds is higher than in non-stimulated seeds; the phosphorus content in maize (sort 'Knezha' - 2L - 611) is increasing mainly in leaves after X-ray irradiation (750 - 1500 R); γ irradiation (7.5 Gy) stimulate the root system (18%) and side roots development and drying up overcome

  14. The influence of maize kernel moisture on the sterilizing effect of gamma rays

    International Nuclear Information System (INIS)

    Khanymova, T.; Poloni, E.

    1980-01-01

    The influence of 4 levels of maize kernel moisture (16, 20, 25 and 30%) on gamma-ray sterilizing effect was studied and the after-effect of radiation on the microorganisms at short term storage was followed up. Maize kernels of the hybrid Knezha-36 produced in 1975 were used. Gamma-ray treatment of the kernels was effected by GUBEh-4000 irradiator at doses of 0.2 and 0.3 Mrad and after that they were stored for a month at 12 deg and 25 deg C and controlled moisture conditions. Surface and subepidermal infection of the kernels was determined immediately post irradiation and at the end of the experiment. Non-irradiated kernels were used as controls. Results indicated that the initial kernel moisture has a considerable influence on the sterilizing effect of gamma-rays at the rates used in the experiment and affects to a considerable extent the post-irradiation recovery of organisms. The speed of recovery was highest in the treatment with 30% moisture and lowest in the treatment with 16% kernel moisture. Irradiation of the kernels causes pronounced changes on the surface and subepidermal infection. This was due to the unequal radio resistance to the microbial components and to the modifying effect of the moisture holding capacity. The useful effect of maize kernel irradiation was more prolonged at 12 deg C than at 25 deg C

  15. Biofuel, land and water: maize, switchgrass or Miscanthus?

    International Nuclear Information System (INIS)

    Zhuang Qianlai; Qin Zhangcai; Chen Min

    2013-01-01

    The productive cellulosic crops switchgrass and Miscanthus are considered as viable biofuel sources. To meet the 2022 national biofuel target mandate, actions must be taken, e.g., maize cultivation must be intensified and expanded, and other biofuel crops (switchgrass and Miscanthus) must be cultivated. This raises questions on the use efficiencies of land and water; to date, the demand on these resources to meet the national biofuel target has rarely been analyzed. Here, we present a data-model assimilation analysis, assuming that maize, switchgrass and Miscanthus will be grown on currently available croplands in the US. Model simulations suggest that maize can produce 3.0–5.4 kiloliters (kl) of ethanol for every hectare of land, depending on the feedstock to ethanol conversion efficiency; Miscanthus has more than twice the biofuel production capacity relative to maize, and switchgrass is the least productive of the three potential sources of ethanol. To meet the biofuel target, about 26.5 million hectares of land and over 90 km 3 of water (of evapotranspiration) are needed if maize grain alone is used. If Miscanthus was substituted for maize, the process would save half of the land and one third of the water. With more advanced biofuel conversion technology for Miscanthus, only nine million hectares of land and 45 km 3 of water would probably meet the national target. Miscanthus could be a good alternative biofuel crop to maize due to its significantly lower demand for land and water on a per unit of ethanol basis. (letter)

  16. Influence of Maize Rotations on the Yield of Soybean Grown in Meloidogyne incognita Infested Soil

    OpenAIRE

    Kinloch, Robert A.

    1983-01-01

    A replicated field study was conducted from 1972 to 1980 involving soybeans grown in 2-, 3-, and 4-year rotations with maize in soil infested with Meloidogyne incognita. Monocultured soybeans were maintained as controls. Cropping regimes involved root-knot nematode susceptible and resistant soybean cultivars and soybeans treated and not treated with nematicides. Yields of susceptible cultivars declined with reduced length of rotation. Nematicide treatment significantly increased yields of sus...

  17. Production of high-amylose maize lines using RNA interference in ...

    African Journals Online (AJOL)

    amylose maize lines with a low T-DNA copy number, demonstrating that RNAi is an efficient method for the production of high-amylose maize lines. Key words: Maize, high-amylose, RNA interference, starch branching enzyme gene sbe2a.

  18. Expression profiling of selected glutathione transferase genes in Zea mays (L.) seedlings infested with cereal aphids.

    Science.gov (United States)

    Sytykiewicz, Hubert; Chrzanowski, Grzegorz; Czerniewicz, Paweł; Sprawka, Iwona; Łukasik, Iwona; Goławska, Sylwia; Sempruch, Cezary

    2014-01-01

    The purpose of this report was to evaluate the expression patterns of selected glutathione transferase genes (gst1, gst18, gst23 and gst24) in the tissues of two maize (Zea mays L.) varieties (relatively resistant Ambrozja and susceptible Tasty Sweet) that were colonized with oligophagous bird cherry-oat aphid (Rhopalosiphum padi L.) or monophagous grain aphid (Sitobion avenae L.). Simultaneously, insect-triggered generation of superoxide anion radicals (O2•-) in infested Z. mays plants was monitored. Quantified parameters were measured at 1, 2, 4, 8, 24, 48 and 72 h post-initial aphid infestation (hpi) in relation to the non-infested control seedlings. Significant increases in gst transcript amounts were recorded in aphid-stressed plants in comparison to the control seedlings. Maximal enhancement in the expression of the gst genes in aphid-attacked maize plants was found at 8 hpi (gst23) or 24 hpi (gst1, gst18 and gst24) compared to the control. Investigated Z. mays cultivars formed excessive superoxide anion radicals in response to insect treatments, and the highest overproduction of O2•- was noted 4 or 8 h after infestation, depending on the aphid treatment and maize genotype. Importantly, the Ambrozja variety could be characterized as having more profound increments in the levels of gst transcript abundance and O2•- generation in comparison with the Tasty Sweet genotype.

  19. The assessment of pellicular anion-exchange resins for the determination of anions by ion chromatography

    International Nuclear Information System (INIS)

    Pohlandt, C.

    1981-01-01

    Because pellicular anion-exchange resins suitable for the determination, by ion chromatography, of anions with alkaline eluents were unavailable in South Africa at the inception of this work, an attempt was made to prepare such resins. In this study it is shown that the pellicular resins produced are more efficient than the surface-aminated resins used previously. The simultaneous separation and determination of five common anions is demonstrated. The method was applied to the analysis of uranium leach liquors, effluent samples, and a solid sample of ferric oxide (goethite)

  20. Iron and manganese oxides modified maize straw to remove tylosin from aqueous solutions.

    Science.gov (United States)

    Yin, Yongyuan; Guo, Xuetao; Peng, Dan

    2018-08-01

    Maize straw modified by iron and manganese oxides was synthesized via a simple and environmentally friendly method. Three maize straw materials, the original maize straw, maize straw modified by manganese oxides and maize straw modified by iron and manganese oxides, were detected by SEM, BET, XPS, XRD and FTIR. The results showed that maize straw was successfully modified and maize straw modified by iron and manganese oxides has a larger surface area than MS. According to the experimental data, the sorption trend could conform to the pseudo-second-order kinetic model well, and the sorption ability of tylosin on sorbents followed the order of original maize straw oxides iron and manganese oxides. The study indicated that manganese oxides and iron-manganese oxides could significantly enhance the sorption capacity of original maize straw. The sorption isotherm data of tylosin on original maize straw fit a linear model well, while Freundlich models were more suitable for maize straw modified by manganese oxides and maize straw modified by iron and manganese oxides. The pH, ionic strength and temperature can affect the sorption process. The sorption mechanisms of tylosin on iron and manganese oxides modified maize straw were attribute to the surface complexes, electrostatic interactions, H bonding and hydrophobic interactions. Copyright © 2018 Elsevier Ltd. All rights reserved.

  1. Photosynthetic properties of erect leaf maize inbred lines as the efficient photo-model in breeding and seed production

    Directory of Open Access Journals (Sweden)

    Radenović Čedomir N.

    2003-01-01

    Full Text Available The initial idea of this study was a hypothesis that erect leaf maize inbred lines were characterized by properties of an efficient photo-model and that as such were very desirable in increasing the number of plants per area unit (plant density in the process of contemporary selection and seed production. The application of a non-invasive bioluminescence-photosynthetic method, suitable for the efficiency estimation of the photo-model, verified the hypothesis. Obtained photosynthetic properties of observed erect leaf maize inbred lines were based on the effects and characteristics of thermal processes of delayed chlorophyll fluorescence occurring in their thylakoid membranes. The temperature dependence of the delayed chlorophyll fluorescence intensity phase transitions (critical temperatures in the thylakoid membranes and activation energy are the principal parameters of the thermal processes. Based on obtained photosynthetic properties it is possible to select erect leaf maize inbred lines that are resistant and tolerant to high and very high temperatures, as well as, to drought. They could be good and efficient photo-models wherewith.

  2. Isolation of the human anionic glutathione S-transferase cDNA and the relation of its gene expression to estrogen-receptor content in primary breast cancer

    International Nuclear Information System (INIS)

    Moscow, J.A.; Townsend, A.J.; Goldsmith, M.E.; Whang-Peng, J.; Vickers, P.J.; Poisson, R.; Legault-Poisson, S.; Myers, C.E.; Cowan, K.H.

    1988-01-01

    The development of multidrug resistance in MCF7 human breast cancer cells is associated with overexpression of P-glycoprotein, changes in activities of several detoxication enzymes, and loss of hormone sensitivity and estrogen receptors (ERs). The authors have cloned the cDNA for one of the drug-detoxifying enzymes overexpressed in multidrug-resistant MCF7 cells (Adr R MCF7), the anionic isozyme of glutathione S-transferase (GSTπ). Hybridization with this GSTπ cDNA, GSTπ-1, demonstrated that increased GSTπ activity in Adr R MCF7 cells is associated with overexpression but not with amplification of the gene. They mapped the GSTπ gene to human chromosome 11q13 by in situ hybridization. Since multidrug resistance and GSTπ overexpression are associated with the loss of ERs in Adr R MCF7 cells, they examined several other breast cancer cell lines that were not selected for drug resistance. In each of these cell lines they found an inverse association between GSTπ expression and ER content. They also examined RNA from 21 primary breast cancers and found a similar association between GSTπ expression and ER content in vivo. The finding of similar patterns of expression of a drug-detoxifying enzyme and of ERs in vitro as well as in vivo suggests that ER-negative breast cancer cells may have greater protection against antineoplastic agents conferred by GSTπ than ER-positive tumors

  3. (SSR) markers for drought tolerance in maize

    African Journals Online (AJOL)

    Maize is moderately sensitive to drought. Drought affects virtually all aspects of maize growth in varying degrees at all stages, from germination to maturity. Tolerance to drought is genetically and physiologically complicated and inherited quantitatively. Application of molecular-marker aided selection technique for ...

  4. EMPIRICAL ASSESSMENT OF THE GROWTH RATE OF MAIZE PRODUCTION IN THE PRE - SAP, SAP AND POST - SAP PERIODS IN NIGERIA

    Directory of Open Access Journals (Sweden)

    Oyinbo Oyakhilomen

    2012-05-01

    Full Text Available This study was carried out to provide empirical evidence on the growth rates of maize production in three sub - periods in Nigeria namely pre - Structural Adjustment Programme period, Structural Adjustment Program period and post - Structural Adjustment Programme period. Secondary data on maize production in Nigeria during the Pre - Structural Adjustment Programme period (1970 to 1985, Structural Adjustment period (1986 to 1994 and post - Structural Adjustment Programme period (1995 to 2007 were employed in this study. A growth rate model was used to estimate the growth rates of maize in the three sub - periods. The results of the analysis showed that the instantaneous growth rates of maize production are - 0.1%, 5.7% and 2.4% and the compound rates of growth of maize production are - 0.001%, 0.059% and 0.024% for the pre - Structural Adjustment Programme, Structural Adjustment Programme and post - Structural Adjustment Programme periods respectively. The higher compound growth rate of maize production in the Structural Adjustment Programme period implies that the policy reforms in the period was more effective in ensuring increased growth of maize production over that of other periods in Nigeria. Therefore, despite the myriads of problems associated with the programme in Nigeria, it was beneficial to maize production in Nigeria.

  5. Perspective: Electrospray photoelectron spectroscopy: From multiply-charged anions to ultracold anions

    International Nuclear Information System (INIS)

    Wang, Lai-Sheng

    2015-01-01

    Electrospray ionization (ESI) has become an essential tool in chemical physics and physical chemistry for the production of novel molecular ions from solution samples for a variety of spectroscopic experiments. ESI was used to produce free multiply-charged anions (MCAs) for photoelectron spectroscopy (PES) in the late 1990 s, allowing many interesting properties of this class of exotic species to be investigated. Free MCAs are characterized by strong intramolecular Coulomb repulsions, which create a repulsive Coulomb barrier (RCB) for electron emission. The RCB endows many fascinating properties to MCAs, giving rise to meta-stable anions with negative electron binding energies. Recent development in the PES of MCAs includes photoelectron imaging to examine the influence of the RCB on the electron emission dynamics, pump-probe experiments to examine electron tunneling through the RCB, and isomer-specific experiments by coupling PES with ion mobility for biological MCAs. The development of a cryogenically cooled Paul trap has led to much better resolved PE spectra for MCAs by creating vibrationally cold anions from the room temperature ESI source. Recent advances in coupling the cryogenic Paul trap with PE imaging have allowed high-resolution PE spectra to be obtained for singly charged anions produced by ESI. In particular, the observation of dipole-bound excited states has made it possible to conduct vibrational autodetachment spectroscopy and resonant PES, which yield much richer vibrational spectroscopic information for dipolar free radicals than traditional PES

  6. The interplay of demography and selection during maize domestication and expansion

    Science.gov (United States)

    The history of maize has been characterized by major demographic events including changes in population size associated with domestication and subsequent range expansion as well as gene flow with wild relatives. This complex demographic history and its interplay with selection have shaped diversity ...

  7. ENZYME RESISTANCE OF GENETICALLY MODIFIED STARCH POTATOES

    Directory of Open Access Journals (Sweden)

    A. Sh. Mannapova

    2015-01-01

    Full Text Available Here in this article the justification of expediency of enzyme resistant starch use in therapeutic food products is presented . Enzyme resistant starch is capable to resist to enzymatic hydrolysis in a small intestine of a person, has a low glycemic index, leads to decrease of postprandial concentration of glucose, cholesterol, triglycerides in blood and insulin reaction, to improvement of sensitivity of all organism to insulin, to increase in sense of fulness and to reduction of adjournment of fats. Resistant starch makes bifidogenшс impact on microflora of a intestine of the person, leads to increase of a quantity of lactobacillus and bifidobacterium and to increased production of butyric acid in a large intestine. In this regard the enzyme resistant starch is an important component in food for prevention and curing of human diseases such as diabetes, obesity, colitis, a cancer of large and direct intestine. One method is specified by authors for imitation of starch digestion in a human body. This method is based on the definition of an enzyme resistance of starch in vitro by its hydrolysis to glucose with application of a glucoamylase and digestive enzyme preparation Pancreatin. This method is used in researches of an enzyme resistance of starch, of genetically modified potato, high amylose corn starch Hi-Maize 1043 and HYLON VII (National Starch Food Innovation, USA, amylopectin and amylose. It is shown that the enzyme resistance of the starch emitted from genetically modified potatoes conforms to the enzyme resistance of the high amylose corn starch “Hi-Maize 1043 and HYLON VII starch”, (National Starch Food Innovation, the USA relating to the II type of enzyme resistant starch. It is established that amylopectin doesn't have the enzyme resistant properties. The results of researches are presented. They allow us to make the following conclusion: amylose in comparison with amylopectin possesses higher enzyme resistance and gives to

  8. A comparative study on infestation of three varieties of maize ( Zea ...

    African Journals Online (AJOL)

    A study was carried out to study the infestation of three maize varieties (Maize suwan I–Y, Maize T2 USR – White single cross and Maize suwan 123) by Sitophilus zeamais Motsch. Infestation was assessed by counting the numbers of alive and dead adults and the number of infested and uninfested seeds. It was found out ...

  9. Increased Abundance and Transferability of Resistance Genes after Field Application of Manure from Sulfadiazine-Treated Pigs

    Science.gov (United States)

    Jechalke, Sven; Kopmann, Christoph; Rosendahl, Ingrid; Groeneweg, Joost; Weichelt, Viola; Krögerrecklenfort, Ellen; Brandes, Nikola; Nordwig, Mathias; Ding, Guo-Chun; Siemens, Jan; Heuer, Holger

    2013-01-01

    Spreading manure containing antibiotics in agriculture is assumed to stimulate the dissemination of antibiotic resistance in soil bacterial populations. Plant roots influencing the soil environment and its microflora by exudation of growth substrates might considerably increase this effect. In this study, the effects of manure from pigs treated with sulfadiazine (SDZ), here called SDZ manure, on the abundance and transferability of sulfonamide resistance genes sul1 and sul2 in the rhizosphere of maize and grass were compared to the effects in bulk soil in a field experiment. In plots that repeatedly received SDZ manure, a significantly higher abundance of both sul genes was detected compared to that in plots where manure from untreated pigs was applied. Significantly lower abundances of sul genes relative to bacterial ribosomal genes were encountered in the rhizosphere than in bulk soil. However, in contrast to results for bulk soil, the sul gene abundance in the SDZ manure-treated rhizosphere constantly deviated from control treatments over a period of 6 weeks after manuring, suggesting ongoing antibiotic selection over this period. Transferability of sulfonamide resistance was analyzed by capturing resistance plasmids from soil communities into Escherichia coli. Increased rates of plasmid capture were observed in samples from SDZ manure-treated bulk soil and the rhizosphere of maize and grass. More than 97% of the captured plasmids belonged to the LowGC type (having low G+C content), giving further evidence for their important contribution to the environmental spread of antibiotic resistance. In conclusion, differences between bulk soil and rhizosphere need to be considered when assessing the risks associated with the spreading of antibiotic resistance. PMID:23315733

  10. Deep sequencing of RNA from ancient maize kernels

    DEFF Research Database (Denmark)

    Fordyce, Sarah Louise; Avila Arcos, Maria del Carmen; Rasmussen, Morten

    2013-01-01

    The characterization of biomolecules from ancient samples can shed otherwise unobtainable insights into the past. Despite the fundamental role of transcriptomal change in evolution, the potential of ancient RNA remains unexploited - perhaps due to dogma associated with the fragility of RNA. We hy...... maize kernels. The results suggest that ancient seed transcriptomics may offer a powerful new tool with which to study plant domestication....

  11. Effects of temperature changes on maize production in Mozambique

    Science.gov (United States)

    Harrison, L.; Michaelsen, J.; Funk, Chris; Husak, G.

    2011-01-01

    We examined intraseasonal changes in maize phenology and heat stress exposure over the 1979-2008 period, using Mozambique meteorological station data and maize growth requirements in a growing degree-day model. Identifying historical effects of warming on maize growth is particularly important in Mozambique because national food security is highly dependent on domestic food production, most of which is grown in already warm to hot environments. Warming temperatures speed plant development, shortening the length of growth periods necessary for optimum plant and grain size. This faster phenological development also alters the timing of maximum plant water demand. In hot growing environments, temperature increases during maize pollination threaten to make midseason crop failure the norm. In addition to creating a harsher thermal environment, we find that early season temperature increases have caused the maize reproductive period to start earlier, increasing the risk of heat and water stress. Declines in time to maize maturation suggest that, independent of effects to water availability, yield potential is becoming increasingly limited by warming itself. Regional variations in effects are a function of the timing and magnitude of temperature increases and growing season characteristics. Continuation of current climatic trends could induce substantial yield losses in some locations. Farmers could avoid some losses through simple changes to planting dates and maize varietal types.

  12. Refeeding syndrome as an unusual cause of anion gap metabolic acidosis.

    Science.gov (United States)

    Singla, Manish; Perry, Alexandra; Lavery, Eric

    2012-11-01

    Refeeding syndrome is characterized by hypophosphatemia in the setting of malnutrition. It is commonly seen in patients with anorexia, alcoholism, or malignancy, and it is often a missed diagnosis. Because of the potential morbidity associated with missing the diagnosis of refeeding syndrome, it is important to monitor for this disease in any malnourished patient. We present a case of a 49-year-old male with chronic alcohol abuse who presented for alcohol detoxification and was found to have low phosphate, potassium, and magnesium on presentation, in addition to an elevated anion gap of unclear etiology. After extensive workup to evaluate the cause of his elevated anion gap and worsening of his electrolyte abnormalities despite replenishment, it was felt his symptoms were a result of refeeding syndrome. After oral intake was held and aggressive electrolyte replenishment was performed for 24 hours, the patient's anion gap closed and his electrolyte levels stabilized. This case demonstrates a unique presentation of refeeding syndrome given the patient's profound metabolic acidosis that provided a clue toward his eventual diagnosis. The standard workup for an anion gap metabolic acidosis was negative, and it was not until his refeeding syndrome had been treated that the anion gap closed.

  13. Seed treatments enhance photosynthesis in maize seedlings by reducing infection with Fusarium spp. and consequent disease development in maize

    Science.gov (United States)

    The effects of a seed treatment on early season growth, seedling disease development, incidence Fusarium spp. infection, and photosynthetic performance of maize were evaluated at two locations in Iowa in 2007. Maize seed was either treated with Cruiser 2Extreme 250 ® (fludioxonil + azoxystrobin + me...

  14. PERFORMANCE OF MAIZE (ZEA MAYS) CULTIVARS AS ...

    African Journals Online (AJOL)

    IBUKUN

    reported to have low remobilisation efficiency and reduced plasticity of seed weight to assimilate availability ... have indicated that the use of organo-mineral fertiliser in maize and melon gave high relative .... The soil physical and chemical characteristics of ..... yield in maize by examining genetic improvement and heterosis.

  15. Deregulation of Lesotho's maize market

    OpenAIRE

    van Schalkwyk, Herman D.; van Zyl, Johan; Botha, P.W.; Bayley, B.

    1997-01-01

    During the past year, there have been major policy reforms in Lesotho and South Africa with respect to maize pricing and marketing. In Lesotho the impact of deregulation on producers, consumers and government revenues was substantially lower than it should have been, and as a result Lesotho was not able to reap the full benefits of these changes. This is partly because information on the changes to the maize marketing system did not reach the potential beneficiaries of the new system. Free an...

  16. Enhanced activity of carbohydrate- and lipid-metabolizing enzymes in insecticide-resistant populations of the maize weevil, Sitophilus zeamais.

    Science.gov (United States)

    Araújo, R A; Guedes, R N C; Oliveira, M G A; Ferreira, G H

    2008-08-01

    Insecticide resistance is frequently associated with fitness disadvantages in the absence of insecticides. However, intense past selection with insecticides may allow the evolution of fitness modifier alleles that mitigate the cost of insecticide resistance and their consequent fitness disadvantages. Populations of Sitophilus zeamais with different levels of susceptibility to insecticides show differences in the accumulation and mobilization of energy reserves. These differences may allow S. zeamais to better withstand toxic compounds without reducing the beetles' reproductive fitness. Enzymatic assays with carbohydrate- and lipid-metabolizing enzymes were, therefore, carried out to test this hypothesis. Activity levels of trehalase, glycogen phosphorylase, lipase, glycosidase and amylase were determined in two insecticide-resistant populations showing (resistant cost) or not showing (resistant no-cost) associated fitness cost, and in an insecticide-susceptible population. Respirometry bioassays were also carried out with these weevil populations. The resistant no-cost population showed significantly higher body mass and respiration rate than the other two populations, which were similar. No significant differences in glycogen phosphorylase and glycosidase were observed among the populations. Among the enzymes studied, trehalase and lipase showed higher activity in the resistant cost population. The results obtained in the assays with amylase also indicate significant differences in activity among the populations, but with higher activity in the resistant no-cost population. The inverse activity trends of lipases and amylases in both resistant populations, one showing fitness disadvantage without insecticide exposure and the other not showing it, may underlay the mitigation of insecticide resistance physiological costs observed in the resistant no-cost population. The higher amylase activity observed in the resistant no-cost population may favor energy storage

  17. Testing Pollen of Single and Stacked Insect-Resistant Bt-Maize on In vitro Reared Honey Bee Larvae

    Science.gov (United States)

    Hendriksma, Harmen P.; Härtel, Stephan; Steffan-Dewenter, Ingolf

    2011-01-01

    The ecologically and economic important honey bee (Apis mellifera) is a key non-target arthropod species in environmental risk assessment (ERA) of genetically modified (GM) crops. Honey bee larvae are directly exposed to transgenic products by the consumption of GM pollen. But most ERA studies only consider responses of adult bees, although Bt-proteins primarily affect the larval phases of target organisms. We adopted an in vitro larvae rearing system, to assess lethal and sublethal effects of Bt-pollen consumption in a standardized eco-toxicological bioassay. The effects of pollen from two Bt-maize cultivars, one expressing a single and the other a total of three Bt-proteins, on the survival and prepupae weight of honey bee larvae were analyzed. The control treatments included pollen from three non-transgenic maize varieties and of Heliconia rostrata. Three days old larvae were fed the realistic exposure dose of 2 mg pollen within the semi-artificial diet. The larvae were monitored over 120 h, until the prepupal stage, where larvae terminate feeding and growing. Neither single nor stacked Bt-maize pollen showed an adverse effect on larval survival and the prepupal weight. In contrast, feeding of H. rostrata pollen caused significant toxic effects. The results of this study indicate that pollen of the tested Bt-varieties does not harm the development of in vitro reared A. mellifera larvae. To sustain the ecosystem service of pollination, Bt-impact on A. mellifera should always be a crucial part of regulatory biosafety assessments. We suggest that our approach of feeding GM pollen on in vitro reared honey bee larvae is well suited of becoming a standard bioassay in regulatory risk assessments schemes of GM crops. PMID:22194811

  18. Testing pollen of single and stacked insect-resistant Bt-maize on in vitro reared honey bee larvae.

    Directory of Open Access Journals (Sweden)

    Harmen P Hendriksma

    Full Text Available The ecologically and economic important honey bee (Apis mellifera is a key non-target arthropod species in environmental risk assessment (ERA of genetically modified (GM crops. Honey bee larvae are directly exposed to transgenic products by the consumption of GM pollen. But most ERA studies only consider responses of adult bees, although Bt-proteins primarily affect the larval phases of target organisms. We adopted an in vitro larvae rearing system, to assess lethal and sublethal effects of Bt-pollen consumption in a standardized eco-toxicological bioassay. The effects of pollen from two Bt-maize cultivars, one expressing a single and the other a total of three Bt-proteins, on the survival and prepupae weight of honey bee larvae were analyzed. The control treatments included pollen from three non-transgenic maize varieties and of Heliconia rostrata. Three days old larvae were fed the realistic exposure dose of 2 mg pollen within the semi-artificial diet. The larvae were monitored over 120 h, until the prepupal stage, where larvae terminate feeding and growing. Neither single nor stacked Bt-maize pollen showed an adverse effect on larval survival and the prepupal weight. In contrast, feeding of H. rostrata pollen caused significant toxic effects. The results of this study indicate that pollen of the tested Bt-varieties does not harm the development of in vitro reared A. mellifera larvae. To sustain the ecosystem service of pollination, Bt-impact on A. mellifera should always be a crucial part of regulatory biosafety assessments. We suggest that our approach of feeding GM pollen on in vitro reared honey bee larvae is well suited of becoming a standard bioassay in regulatory risk assessments schemes of GM crops.

  19. Growing sensitivity of maize to water scarcity under climate change.

    Science.gov (United States)

    Meng, Qingfeng; Chen, Xinping; Lobell, David B; Cui, Zhenling; Zhang, Yi; Yang, Haishun; Zhang, Fusuo

    2016-01-25

    Climate change can reduce crop yields and thereby threaten food security. The current measures used to adapt to climate change involve avoiding crops yield decrease, however, the limitations of such measures due to water and other resources scarcity have not been well understood. Here, we quantify how the sensitivity of maize to water availability has increased because of the shift toward longer-maturing varieties during last three decades in the Chinese Maize Belt (CMB). We report that modern, longer-maturing varieties have extended the growing period by an average of 8 days and have significantly offset the negative impacts of climate change on yield. However, the sensitivity of maize production to water has increased: maize yield across the CMB was 5% lower with rainfed than with irrigated maize in the 1980s and was 10% lower (and even >20% lower in some areas) in the 2000s because of both warming and the increased requirement for water by the longer-maturing varieties. Of the maize area in China, 40% now fails to receive the precipitation required to attain the full yield potential. Opportunities for water saving in maize systems exist, but water scarcity in China remains a serious problem.

  20. Effect and fate of lindane in maize plant

    International Nuclear Information System (INIS)

    Bennaceur, M.; Ghezal, F.; Klaa, K.

    1992-10-01

    The fate and effect of lindane in maize plant, soil and predators were studied following insecticide application under field conditions. Respectively 84,2% and 93,3% of lindane residues were lost after 2 and 4 months in soil after treatment. About 90% of the insecticide was lost after one month in maize plant. Lindane residues were present in maize grains (0,205ppm). Lindane decreases the density of many predators in soils such as species of collembola, coccinellidae, formicidae, coleoptera