Pauly, Markus; Hake, Sarah; Kraemer, Florian J
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.
Full Text Available In order to identify morphological variation in maize inbred lines, one hundred five inbred lines were planted under randomized complete block design with two replications at research field of National Maize Research Program, Rampur, Chitwan, Nepal during summer season (March to June, 2010. Descriptive statistics and cluster analysis were done. The results revealed a wide range of morphological variation among the tested inbred lines. The inbred lines grouped in cluster 4 namely PUTU-13, L-9, RL-105, RL-197, RL-103, RML-9, RML-41, RL-165, RL-36, RL-76, RL-125, RL-30-3, L-6, RL-107, RL-174, RL-41, L-13, RML-76 and L-5 had 0.833 days anthesis-silking interval and earlier in flowering (tasseling in 54.50 days and silking in 55.33 days. Moreover they consisted of 1.16 plant aspect, 1.25 ear aspect, 33.08 cm tassel length and 13.5 tassel branch number. Among tested lines, the above inbred lines had better morphological traits, so it was concluded that they were good candidates for development of hybrids and synthetic varieties. DOI: http://dx.doi.org/10.3126/ije.v3i2.10521 International Journal of the Environment Vol.3(2 2014: 98-107
Jun 3, 2008 ... Eight maize inbred lines and three open pollinated varieties from Sudan were evaluated for their response to tissue ... Keywords: Sudanese maize genotypes, embryogenic callus, regeneration, and tissue culture. INTRODUCTION .... genes have been implicated in the inheritance of callus induction and ...
Eight maize inbred lines and three open pollinated varieties from Sudan were evaluated for their response to tissue culture. Immature embryos obtained 16 days after pollination were used as explants for callus induction. Calli were induced on LS medium supplemented with 2 mg/L 2,4-dichlorophenoxyacetic acid.
estimate combining ability effects of locally developed and introduced early generation maize inbred lines for grain yield, yield .... mass selection followed by self-pollination for generating inbred lines. The inbred lines ... for the experiment was an alpha (0, 1) lattice (Patterson and Williams, 1996) with two replications at each ...
Prof. Adipala Ekwamu
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 ...
Boćanski Jan; Nastasić Aleksandra; Stanisavljević Dušan; Srećkov Zorana; Mitrović Bojan; Treskić Sanja; Vukosavljev Mirjana
Bocanski J., A. Nastasic, D. Stanisavljevic, Z. Sreckov, B. Mitrovic, S. Treskic and M. Vukosavljev (2011): Biplot analysis of diallel crosses of NS maize inbred lines- Genetika, Vol 43, No. 2, 277 - 284. Genetic markers, from morphological to molecular, in function with early Heterosis is a prerequisite for the successful commercial maize production. It does not appear in any cross of two inbred lines, and therefore, the determination of combining abilities of parental lines is essential. Th...
Full Text Available This paper presents the analysis of results obtained during long- term studies on the response of maize inbred lines to herbicides. Under the agroecological conditions of Zemun Polje the response (reaction of maize inbred lines to herbicides of different classes was investigated. Biological tests were performed and some agronomic, morphological, physiological and biochemical parameters were determined when the response of maize inbred lines to herbicides was estimated. The use of active ingredients of herbicides from triazine, acetanilide, thiocarbamate to new chemical groups (sulfonylurea etc., have been resulted in changes in weed suppression and susceptibility of inbred lines. Obtained results show that effects of herbicides on susceptible maize genotypes can be different: they can slowdown the growth and development and affect the plant height; they can also affect the stages of the tassel and ear development and at the end they can reduced grain yield of the tested inbreds. Numerous studies confirmed the existence of differences in susceptibility level of maize genotypes in relation to herbicides. According to gained results the recommendations for growers are made on the possibility of the application of new herbicides in the hybrid seed production.
estimate combining ability effects of locally developed and introduced early generation maize inbred lines for grain ... variance revealed significant difference among the hybrids for all studied traits. General ... Guto LMS5, L15 x SC22 and L20 x TSC22) gave significantly higher grain yield advantage over the two standard ...
Bocanski, J.; Nastasic, A.; Stanisavljevic, D.; Sreckov, Z.; Mitrovic, B.; Treskic, S.; Vukosavljev, M.
Bocanski J., A. Nastasic, D. Stanisavljevic, Z. Sreckov, B. Mitrovic, S. Treskic and M. Vukosavljev (2011): Biplot analysis of diallel crosses of NS maize inbred lines- Genetika, Vol 43, No. 2, 277 - 284. Genetic markers, from morphological to molecular, in function with early Heterosis is a
Assessment of genetic variability of maize inbred lines and their hybrids under normal and drought conditions. ... Nigeria Agricultural Journal ... Analysis of variance revealed significant differences for most of the characters under study which indicates the presence of sufficient amount of variability offering ample scope for ...
Full Text Available Genetic markers, from morphological to molecular, in function with early Heterosis is a prerequisite for the successful commercial maize production. It does not appear in any cross of two inbred lines, and therefore, the determination of combining abilities of parental lines is essential. The most commonly used method for determining combining abilities is diallel analysis. Besides conventional methods for diallel analysis, a new biplot approach has been sugested. In this paper, we studied the combining ability for grain yield in a set of genotypes obtained by diallel crossing system of six inbred lines. Both, the Griffing’s conventional method and the biplot approach have been used for diallel analysis. Comparing the GCA values from biplot analysis and Griffing’s method, similar results can be observed, with the exception of NS L 1051 and NS L 1000 whose ranks are interchanged. Biplot analysis enables the SCA estimation of parent inbred, and the highest SCA has inbred B73D. Biplot analysis also allows the estimation of the best crosses. Inbred B73D shows the best results when crossed with testers Mo17Ht, NS L 1051 and N152, inbred N152 combines best with testers NS L 1001 and NS L 1000, whereas the cross of inbred NS L 1051 with tester B73D results with the highest grain yield per plant in comparison with other testers.
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 ...
Full Text Available Here we describe the results of the detailed array-based genotyping obtained by using the Illumina MaizeSNP50 BeadChip of eleven inbred lines belonging to different heterotic groups relevant for maize breeding in Southeast Europe - European Corn Belt. The objectives of this study were to assess the utility of the MaizeSNP50 BeadChip platform by determining its descriptive power and to assess genetic dissimilarity of the inbred lines. The distribution of the SNPs was found not completely uniform among chromosomes, but average call rate was very high (97.9% and number of polymorphic loci was 33200 out of 50074 SNPs with known mapping position indicating descriptive power of the MaizeSNP50 BeadChip. The dendrogram obtained from UPGMA cluster analysis as well as principal component analysis (PCA confirmed pedigree information, undoubtedly distinguishing lines according to their background in two population varieties of Reid Yellow Dent and Lancaster Sure Crop. Dissimilarity analysis showed that all of the inbred lines could be distinguished from each other. Whereas cluster analysis did not definitely differentiate Mo17 and Ohio inbred lines, PCA revealed clear genetic differences between them. The studied inbred lines were confirmed to be genetically diverse, representing a large proportion of the genetic variation occurring in two maize heterotic groups.
This experiment was, therefore, conducted to investigate the general (GCA) and specific (SCA) combining ability of selected maize inbred lines for grain yield and GLS disease resistance. Eight maize inbred lines with contrasting reactions to GLS were crossed in diallel mating to generate 28 hybrids. The parents and ...
Castano-Duque, Lina; Loades, Kenneth W; Tooker, John F; Brown, Kathleen M; Paul Williams, W; Luthe, Dawn S
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.
Full Text Available Mineral elements deficiency in food can cause serious health problems. Being one of the three most importatnt macroelements for plant nutrition, phosphorus is involved in several key processes: photosynthesis, respiration, synthesis of starch, transport of carbohydrates and products of photosynthesis, cell division and increased water utilization. The objective of this study was to estimate the dynamics of inorganic phosphorus (Pi, as a precursor in the synthesis of phytic acid, and phytic phosphorus (Pphy accumulation during the grain filling of two maize inbred lines differing in FAO maturity groups - L217 and L773. In addition, possible linkage between phosphorus content in grain and agro-morphological performances was observed. For the analysis of the dynamics in Pi and Pphy contents, seed samples were taken at 15th, 30th, 45th and 60th day after the polination. The obtained results showed a continuous decline of Pi content in both genotypes, with the most intensive decline observed at the first interval (e.i. 15-30 days after the polination. The trend observed was much more pronounced in L217. Moreover, this inbred acheaved higher grain yield for 61.8 % at first sowing and for 63.1 % at 10-day delayed sowing, respectively, compared to inbred L773. In all three intervals observed, the decrease of Pi content was highly correlated with Pphy content increase for both genotypes. Based on lower accumulation rate, followed by lower Pphy content (2.635 mg g-1 during the stage of physiological maturuty, it could be concluded that inbred L217 could be considered as potentialy suitable genotype for low-phytic hybride selection.
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 ...
Cleso Antônio Patto Pacheco
Full Text Available The study of inbreeding depression is important for breeding strategies such as use of inbred progenies or extraction of inbreed lines. A diallel of 28 maize open-pollinated varieties was evaluated in 10 environments in the early 1990s. At the same time, S1 populations for each of the 28 varieties were evaluated in the same 10 experiments (environments. Yield reductions of the populations from S0 to S1 (mean of the 10 environments, varied from 34.6% (CMS-01 to 59.2% (CMS-30, with an average of 49.1%. Inbreeding depression was greater in populations with a wider genetic base, which had never been exposed to inbreeding (CMS-30, BR-107, PH4, Cunha, Saracura, Nitrodent, and Nitroflint. Inbred lines with greater yield means should be obtained from the BR-105, BR-111, CMS-01, CMS-03, BR-106, CMS-14c, and CMS-28 populations. The use of parameter estimates generated by analysis of inbreeding depression, allow to make inferences about frequencies of deleterious alleles in the population. The frequencies of favorable alleles in the parents can be obtained by diallel analysis. The association of these two types of information, can provide a better interpretation of the genetic parameters and also can improve the process of selection of parents for either an intra- or an inter-populational breeding program.
% percent of regenerants were normal and fertile. The successful regeneration of some of the inbred lines and/or hybrids provides a basis for development of genetic transformation using Agrobacterium tumefaciens to improve priority traits such ...
Andersen, Jeppe Reitan; Zein, Imad; Wenzel, Gerhard
genomic fragments of six putative phenylpropanoid pathway genes in a panel of elite European inbred lines of maize (Zea mays L.) contrasting in forage quality traits. Six loci, encoding C4H, 4CL1, 4CL2, C3H, F5H, and CAD, displayed different levels of nucleotide diversity and linkage disequilibrium (LD...
Performance data of maize varieties at different locations needs to be accurate and accessible to stimulate the improvement of the Nigerian maize seed system. This paper describes a database model to implement a simple computerized information system for maize varieties and their performance at various locations in ...
Pereira, G S; Pinho, R G V; Pinho, E V R V; Pires, L P M; Bernardo Junior, L A Y; Pereira, J L A; Melo, M P
In recent years, there has been a large incidence of fungi causing "ear rot" in maize in Brazil, the main fungus being Fusarium verticillioides. The most efficient and competitive alternative for control of this disease consists of using maize hybrids resistant to this pathogen. Thus, the aims of this study were to analyze the genetic variability of maize inbred lines in regard to resistance to ear rot to observe if there is a maternal effect to resistance to ear rot, to study genetic control of the traits evaluated in hybrids originating from inbred lines of the maize breeding program at the Agriculture Department of Universidade Federal de Lavras (Lavras, MG, Brazil), and characterize the gene expression pattern related to the plant defense mechanism against F. verticillioides. High genetic availability was observed for resistance to this disease among the inbred lines evaluated. Considering combined diallel analysis, it was observed that the mean square of general combining ability (GCA) was not significant for the characteristic under study. However, specific combining ability (SCA) was significant, which indicates the predominance of non-additive effects involved in control of the characteristic for the population evaluated. A maternal effect was not observed for the characteristic of ear rot resistance in this study. Inbred lines 22, 58, and 91 showed potential for use in breeding programs aiming at resistance to F. verticillioides. Only two genes, LOX8 and Hsp82, had a satisfactory result that was able to be related to a plant defense mechanism when there is ear rot infection, though expression of these genes was observed in only one susceptible genotype. Thus, the genes LOX8 and Hsp82 are potential molecular markers for selection of maize inbred lines resistant to F. verticillioides.
Jun 3, 2008 ... Keywords: Sudanese maize genotypes, embryogenic callus, regeneration, and tissue culture. INTRODUCTION. Maize is an important food and forage crop in the North- ern and Southern regions of ... Skoog, 1965) containing 60 g l-1 sucrose and lacking 2,4-D (referred to as maturation or RI medium) and ...
Melchinger, A E; Lee, M; Lamkey, K R; Hallauer, A R; Woodman, W L
Changes that may have occurred over the past 50 years of hybrid breeding in maize (Zea maize L.) with respect to heterosis for yield and heterozygosity at the molecular level are of interest to both maize breeders and quantitative geneticists. The objectives of this study were twofold: The first, to compare two diallels produced from six older maize inbreds released in the 1950's and earlier and six newer inbreds released during the 1970's with respect to (a) genetic variation for restriction fragment length polymorphisms (RFLPs) and (b) the size of heterosis and epistatic effects, and the second, to evaluate the usefulness of RFLP-based genetic distance measures in predicting heterosis and performance of single-cross hybrids. Five generations (parents, F1; F2, and backcrosses) from the 15 crosses in each diallel were evaluated for grain yield and yield components in four Iowa environments. Genetic effects were estimated from generation means by ordinary diallel analyses and by the Eberhart-Gardner model. Newer lines showed significantly greater yield for inbred generations than did older lines but smaller heterosis estimates. In most cases, estimates of additive x additive epistatic effects for yield and yield components were significantly positive for both groups of lines. RFLP analyses of inbred lines included two restriction enzymes and 82 genomic DNA clones distributed over the maize genome. Eighty-one clones revealed polymorphisms with at least one enzyme. In each set, about three different RFLP variants were typically found per RFLP locus. Genetic distances between inbred lines were estimated from RFLP data as Rogers' distance (RD), which was subdivided into general (GRD) and specific (SRD) Rogers' distances within each diallel. The mean and range of RDs were similar for the older and newer lines, suggesting that the level of heterozygosity at the molecular level had not changed. GRD explained about 50% of the variation among RD values in both sets. Cluster
Deoclecio Domingos Garbuglio
Full Text Available Inbreeding can potentially be used for the development of inbred lines containing alleles of interest, but the genetic causes that control inbreeding depression are not completely known, and there are few studies found in the literature. The present study aimed to obtain estimates of inbreeding depression for eight traits in seven tropical maize populations, analyze the effects of inbreeding over generations and environments, and predict the behavior of inbred lines in future generation S? through linear regression methods. It was found that regardless of the base population used, prediction values could vary when the model was based on only 2 generations of inbreeding due to the environmental component. The influence of the environment in this type of study could be reduced when considering 3 generations of inbreeding, allowing greater precision in predicting the phenotypes of inbred lines. The use of linear regression was effective for inbred line prediction for the different agronomic traits evaluated. The use of 3 levels of inbreeding minimizes the effects of the environmental component in inbred line prediction for grain yield. GO-S was the most promising population for inbred line extraction.
N6 supplemented with 2 mg/l of 2,4-D has shown highest percentage of embryogenic callus induction. Among the five genotypes tested, CM300 gave highest percentage of embryogenic calli. CM300 and LM5 both have shown higher regeneration percentage of 12.22%. Key words: Maize, in-vitro culture and regeneration.
Full Text Available This study encompass the investigation on combining abilities of six maize inbred lines and their diallel hybrids of F1 generation for dry matter yield of both, the whole plant and the ear. The analysis of combining abilities was performed following Griffing (1956 method 2, model I, without reciprocal crosses, while the analysis the genetic components of variance and the regression analysis were done after the model proposed by Hayman and Jinks (1954 and Mather and Jink (1971. Dominant gene effects in inheritance of dry matter yield of the whole plant and the ear were determined by the analysis of combining abilities. The role of these effects are also observable from the analysis of genetic components of variations and results of the Vr/Wr regression analysis. The inbred line ZPLB 406 was the inbred with the highest GCA effects. .
Tamindžić, Gordana D.; Nikolić, Zorica T.; Savić, Jasna Ž.; Milošević, Dragana N.; Petrović, Gordana R.; Ivanović, Dragana D.; Ignjatov, Maja V.
Seed treatment is a common way of fungicide and insecticide use nowadays, since this way of pesticide application can provide the best protection in the vicinity of the future plant. The aim of research was to evaluate the effects of different seed treatments on germination and seedling growth in three maize inbred lines. The research included the seed treatment with several combinations of a fungicide Maxim XL 035-FS (a.i. metalaxil-M + fludioxonil) and ne...
KUMAR, Girjesh; RAI, Prashant KUMAR
Gamma irradiation can induce beneficial as well as deleterious impacts on chromosome behavior in crop plants. The cytogenetic changes occurring due to the storage of inbred seeds after gamma irradiation in the somatic and gametic cells of Zea mays L. were investigated in this study. A wide spectrum of chromosomal anomalies was encountered in somatic and gametic cells of maize that are gamma irradiated, stored (aged), and treated with a combination of both of these treatments. Gamma rays and a...
Andrić Luka; Kovačević Vlado; Kadar Imre; Jambrović Antun; Plavšić Hrvoje; Šimić Domagoj
Boron (B) deficiency in maize can result in barren cobs attributed to silks being nonreceptive which is particularly important for the female parent in seed production. The objectives of this study were 1) to investigate genotypic differences among nine female inbred lines used in seed production for B concentration in ear-leaf and grain, as well as for grain yield and moisture in a three-year experiment (2006-2008) and 2) to determine response and relation...
Krishna, M S R; Sokka Reddy, S; Satyanarayana, Sadam D V
Improvement of quality protein maize (QPM) along with high content of lysine and tryptophan had foremost importance in maize breeding program. The efficient and easiest way of developing QPM hybrids was by backcross breeding in marker aided selection. Hence, the present investigation aimed at conversion of elite maize inbred line BML-7 into QPM line. CML-186 was identified to be a donor variety as it revealed high-quality polymorphism with BML-7 for opaque-2 gene specific marker umc1066. Non-QPM inbred line BML-7 was crossed with QPM donor CML-186 and produced F 1 followed by the development of BC 1 F 1 and BC 2 F 1 population. Foreground selection was carried out with umc1066 in F 1 , and selected plants were used for BC 1 F 1 and BC 2 F 1 populations. Two hundred plants were screened in both BC 1 F 1 and BC 2 F 1 population with umc1066 for foreground selection amino acid modifiers. Foreground selected plants for both opaque-2 and amino acid modifiers were screened for background selection for BML-7 genome. Recurrent parent genome (RPG) was calculated for BC 2 F 1 population plants. Two plants have shown with RPG 90-93% in two generation with back cross population. Two BC 2 F 2 populations resulted from marker recognized BC 2 F 1 individuals subjected toward foreground selection followed by tryptophan estimation. The tryptophan and lysine concentration was improved in all the plants. BC 2 F 2 lines developed from hard endosperm kernels were selfed for BC 2 F 2 lines and finest line was selected to illustrate the QPM version of BML-7, with 0.97% of tryptophan and 4.04% of lysine concentration in protein. Therefore, the QPM version of BML-7 line can be used for the development of single cross hybrid QPM maize version.
Paschold, Anja; Jia, Yi; Marcon, Caroline; Lund, Steve; Larson, Nick B.; Yeh, Cheng-Ting; Ossowski, Stephan; Lanz, Christa; Nettleton, Dan; Schnable, Patrick S.; Hochholdinger, Frank
Typically, F1-hybrids are more vigorous than their homozygous, genetically distinct parents, a phenomenon known as heterosis. In the present study, the transcriptomes of the reciprocal maize (Zea mays L.) hybrids B73×Mo17 and Mo17×B73 and their parental inbred lines B73 and Mo17 were surveyed in primary roots, early in the developmental manifestation of heterotic root traits. The application of statistical methods and a suitable experimental design established that 34,233 (i.e., 86%) of all high-confidence maize genes were expressed in at least one genotype. Nearly 70% of all expressed genes were differentially expressed between the two parents and 42%–55% of expressed genes were differentially expressed between one of the parents and one of the hybrids. In both hybrids, ∼10% of expressed genes exhibited nonadditive gene expression. Consistent with the dominance model (i.e., complementation) for heterosis, 1124 genes that were expressed in the hybrids were expressed in only one of the two parents. For 65 genes, it could be shown that this was a consequence of complementation of genomic presence/absence variation. For dozens of other genes, alleles from the inactive inbred were activated in the hybrid, presumably via interactions with regulatory factors from the active inbred. As a consequence of these types of complementation, both hybrids expressed more genes than did either parental inbred. Finally, in hybrids, ∼14% of expressed genes exhibited allele-specific expression (ASE) levels that differed significantly from the parental-inbred expression ratios, providing further evidence for interactions of regulatory factors from one parental genome with target genes from the other parental genome. PMID:23086286
Mikić, S.; Zorić, M.; Stanisavljević, D.; Kondić-Špika, A.; Brbaklić, L.; Kobiljski, B.; Nastasić, A.; Mitrović, B.; Šurlan-Momirović, G.
Drought is a severe threat to maize yield stability in Serbia and other temperate Southeast European countries occurring occasionally but with significant yield losses. The development of resilient genotypes that perform well under drought is one of the main focuses of maize breeding programmes. To test the tolerance of newly developed elite maize inbred lines to drought stress, field trials for grain yield performance and anthesis silk interval (ASI) were set in drought stressed environments in 2011 and 2012. Inbred lines performing well under drought, clustered into a group with short ASI and a smaller group with long ASI, were considered as a potential source for tolerance. The former contained inbreds from different heterotic groups and with a proportion of local germplasm. The latter consisted of genotypes with mixed exotic and Lancaster germplasm, which performed better in more drought-affected environments. Three inbreds were selected for their potential drought tolerance, showing an above-average yield and small ASI in all environments. Association analysis indicated significant correlations between ASI and grain yield and three microsatellites (bnlg1525, bnlg238 and umc1025). Eight alleles were selected for their favourable concurrent effect on yield increase and ASI decrease. The proportion of phenotypic variation explained by the markers varied across environments from 5.7% to 22.4% and from 4.6% to 8.1% for ASI and yield, respectively. The alleles with strongest effect on performance of particular genotypes and their interactions in specific environments were identified by the mean of partial least square interactions analysis indicating potential suitability of the makers for tolerant genotype selection.
Mikić, S.; Zorić, M.; Stanisavljević, D.; Kondić-Špika, A.; Brbaklić, L.; Kobiljski, B.; Nastasić, A.; Mitrović, B.; Šurlan-Momirović, G.
Drought is a severe threat to maize yield stability in Serbia and other temperate Southeast European countries occurring occasionally but with significant yield losses. The development of resilient genotypes that perform well under drought is one of the main focuses of maize breeding programmes. To test the tolerance of newly developed elite maize inbred lines to drought stress, field trials for grain yield performance and anthesis silk interval (ASI) were set in drought stressed environments in 2011 and 2012. Inbred lines performing well under drought, clustered into a group with short ASI and a smaller group with long ASI, were considered as a potential source for tolerance. The former contained inbreds from different heterotic groups and with a proportion of local germplasm. The latter consisted of genotypes with mixed exotic and Lancaster germplasm, which performed better in more drought-affected environments. Three inbreds were selected for their potential drought tolerance, showing an above-average yield and small ASI in all environments. Association analysis indicated significant correlations between ASI and grain yield and three microsatellites (bnlg1525, bnlg238 and umc1025). Eight alleles were selected for their favourable concurrent effect on yield increase and ASI decrease. The proportion of phenotypic variation explained by the markers varied across environments from 5.7% to 22.4% and from 4.6% to 8.1% for ASI and yield, respectively. The alleles with strongest effect on performance of particular genotypes and their interactions in specific environments were identified by the mean of partial least square interactions analysis indicating potential suitability of the makers for tolerant genotype selection.
Md Moinul Haque
Full Text Available Hybrid rice varieties have higher yield potential over inbred varieties. This improvement is not always translated to the grain yield and its physiological causes are still unclear. In order to clarify it, two field experiments were conducted including two popular indica hybrids (BRRI hybrid dhan2 and Heera2 and one elite inbred (BRRI dhan45 rice varieties. Leaf area index, chlorophyll status, and photosynthetic rate of flag leaf, postheading crop growth rate, shoot reserve translocation, source-sink relation and yield, and its attributes of each variety were comprehensively analyzed. Both hybrid varieties outyielded the inbred. However, the hybrids and inbred varieties exhibited statistically identical yield in late planting. Both hybrids accumulated higher amount of biomass before heading and exhibited greater remobilization of assimilates to the grain in early plantings compared to the inbred variety. Filled grain (% declined significantly at delayed planting in the hybrids compared to elite inbred due to increased temperature impaired-inefficient transport of assimilates. Flag leaf photosynthesis parameters were higher in the hybrid varieties than those of the inbred variety. Results suggest that greater remobilization of shoot reserves to the grain rendered higher yield of hybrid rice varieties.
Full Text Available Maize has always been under constant human selection ever since it had been domesticated. Intensive breeding programs that resulted in the massive use of hybrids nowadays have started in the 60s. That brought significant yield increases but reduced the genetic diversity at the same time. Consequently, breeders and researchers alike turned their attention to national germplasm collections established decades ago in many countries, as they may hold allelic variations that could prove useful for future improvements. These collections are mainly composed of inbred lines originating from well-adapted local open pollinated varieties. However, there is an overall lack of data in the literature about the genetic diversity of maize in SE Europe, and its potential for future breeding efforts. There are no data, whatsoever, on the nutritional quality of the grain, primarily dictated by the zein proteins. We therefore sought to use the Romanian maize germplasm as an entry point in understanding the molecular make-up of maize in this part of Europe. By using 80 SSR markers, evenly spread throughout the genome, on 82 inbred lines from various parts of the country, we were able to decipher population structure and the existing relationships between those and the eight international standards used, including the reference sequenced genome B73. Corroborating molecular data with a standardized morphological, physiological, and biochemical characterization of all 90 inbred lines, this is the first comprehensive such study on the existing SE European maize germplasm. The inbred lines we present here are an important addition to the ever-shrinking gene pool that the breeding programs are faced-with, because of the allelic richness they hold. They may serve as parental lines in crosses that will lead to new hybrids, characterized by a high level of heterosis, nationwide and beyond, due to their existing relationship with the international germplasm.
research materials and financial support during the period of this study. Thanks are extended to the technical staff in the. Department for their assistance during data collection. REFERENCES. Abebe F, Tefera T, Mugo S, Beyene Y and. Vidal S 2009 Resistance of maize varieties to the maize weevil Sitophilus zeamais.
Full Text Available Conventional breeding methods have been aided by molecular genetic techniques giving the chance for efficient improvement in creation of maize hybrids. Proper choice of statistical methods for data analysis is very important because it ensures greater reliability. The aim of this study was to determine the most suitable statistical approach for molecular marker data analysis. SSR markers were used for the analysis of 10 maize inbreds. Genetic similarity/distance was calculated using three types of data: binary, allele frequency based on densitometry and allele frequency according to band size data applying Simple matching, Jaccard's and Rogers' coefficient. Cluster analysis was performed in NTSYS, 2.11a software. The highest value for Spearman's rank of correlation (0.95 was detected between distance matrices based on binary data. The results showed that binary data Jaccard's coefficient and allele frequency data based on fragment sizes (Rogers' coefficient gave identical clusters by visual inspection and according to CIc index.
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
Li, Kun; Yan, Jianbing; Li, Jiansheng; Yang, Xiaohong
Maize (Zea Mays L.) is one of the most important cereal crops worldwide and provides food for billions of people. Stalk lodging can greatly undermine the standability of maize plants and therefore decrease crop yields. Rind penetrometer resistance is an effective and reliable method for evaluating maize stalk strength, which is highly correlated with stalk lodging resistance. In this study, two recombinant inbred line populations were constructed from crosses between the H127R and Chang7-2 lines, and between the B73 and By804 lines. We genotyped these two populations and their parents using 3,072 single nucleotide polymorphism markers and performed phenotypic assessment of rind penetrometer resistance in multiple environments to dissect the genetic architecture of rind penetrometer resistance in maize. Based on two linkage maps of 1,397.1 and 1,600.4 cM with average interval of 1.7 and 2.1 cM between adjacent makers, respectively, seven quantitative trait loci (QTL) for rind penetrometer resistance were detected in the two recombinant inbred line populations. These QTL were distributed in seven genomic regions, and each accounted for 4.4-18.9% of the rind penetrometer resistance variation. The QTL with the largest effect on rind penetrometer resistance, qRPR3-1, was located on chromosome 3 with the flanking markers PZE-103123325 and SYN23245. This locus was further narrowed down to a 3.1-Mb interval by haplotype analysis using high-density markers in the target region. Within this interval, four genes associated with the biosynthesis of cell wall components were considered as potential candidate genes for the rind penetrometer resistance effect. The inheritance of rind penetrometer resistance is rather complex. A few large-effect quantitative trait loci, together with a several minor-effect QTL, contributed to the phenotypic variation in rind penetrometer resistance in the two recombinant inbred line populations that were examined. A potential approach for
Zambrano, Jose Luis; Jones, Mark W; Brenner, Eric; Francis, David M; Tomas, Adriana; Redinbaugh, Margaret G
Novel and previously known resistance loci for six phylogenetically diverse viruses were tightly clustered on chromosomes 2, 3, 6 and 10 in the multiply virus-resistant maize inbred line, Oh1VI. Virus diseases in maize can cause severe yield reductions that threaten crop production and food supplies in some regions of the world. Genetic resistance to different viruses has been characterized in maize populations in diverse environments using different screening techniques, and resistance loci have been mapped to all maize chromosomes. The maize inbred line, Oh1VI, is resistant to at least ten viruses, including viruses in five different families. To determine the genes and inheritance mechanisms responsible for the multiple virus resistance in this line, F1 hybrids, F2 progeny and a recombinant inbred line (RIL) population derived from a cross of Oh1VI and the virus-susceptible inbred line Oh28 were evaluated. Progeny were screened for their responses to Maize dwarf mosaic virus, Sugarcane mosaic virus, Wheat streak mosaic virus, Maize chlorotic dwarf virus, Maize fine streak virus, and Maize mosaic virus. Depending on the virus, dominant, recessive, or additive gene effects were responsible for the resistance observed in F1 plants. One to three gene models explained the observed segregation of resistance in the F2 generation for all six viruses. Composite interval mapping in the RIL population identified 17 resistance QTLs associated with the six viruses. Of these, 15 were clustered in specific regions of chr. 2, 3, 6, and 10. It is unknown whether these QTL clusters contain single or multiple virus resistance genes, but the coupling phase linkage of genes conferring resistance to multiple virus diseases in this population could facilitate breeding efforts to develop multi-virus resistant crops.
Raji, Jennifer A; Frame, Bronwyn; Little, Daniel; Santoso, Tri Joko; Wang, Kan
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.
Casa, A M; Mitchell, S E; Smith, O S; Register, J C; Wessler, S R; Kresovich, S
Recently, a new type of molecular marker has been developed that is based on the presence or absence of the miniature inverted repeat transposable element (MITE) family Heartbreaker ( Hbr) in the maize genome. These so-called Hbr markers have been shown to be stable, highly polymorphic, easily mapped, and evenly distributed throughout the maize genome. In this work, we used Hbr-derived markers for genetic characterization of a set of maize inbred lines belonging to Stiff Stalk (SS) and Non-Stiff Stalk (NSS) heterotic groups. In total, 111 markers were evaluated across 62 SS and NSS lines. Seventy six markers (68%) were shared between the two groups, and 25 of the common markers occurred at fairly low frequency (Hbr data were congruent with those derived from pedigree information). Distance matrices generated from Hbr markers were significantly correlated ( pHbr markers could be used in conjunction with other molecular markers for genotyping and relationship studies of related maize inbred lines.
Full Text Available The development, deployment and production of stress tolerant provitamin A maize is crucial to the fight against vitamin A deficiency in sub-Saharan Africa (SSA where maize is a major staple food crop. Fifteen early maturing provitamin A and two early normal yellow endosperm maize inbreds were crossed using the diallel mating design to generate 136 single-cross hybrids. The hybrids were evaluated during 2015 growing season at three locations under two Striga infested and three optimal growing environments in Nigeria. The objectives were to (i determine the combining ability and heterotic groups of early maturing provitamin A inbreds; (ii examine the performance of the inbreds in hybrid combinations across environments and (iii identify early maturing provitamin A inbred testers for use in tropical maize breeding programs. The general combining ability (GCA and specific combining ability (SCA effects were significant for grain yield and most other traits indicating that additive and non-additive genetic effects were important in the inheritance of these characters. Inbreds TZEI 10, TZEIOR 108, and TZEI 17 had significant positive GCA for grain yield. TZEIOR 108, TZEIOR 42, and TZEI 10 had significant negative GCA for Striga damage while TZEIOR 122, TZEIOR 127, TZEIOR 108, and TZEI 10 had significant negative GCA for number of emerged Striga plants. The inbreds were classified based on heterotic groups’ SCA and GCA of grain yield (HSGCA, SCA and GCA of multiple traits (HGCAMT methods into four, three and five heterotic groups, respectively. The inbreds TZEIOR 108, TZEI 10 and TZEI 17 were identified as testers. Hybrids 8, 3, 5, 10 and 1 were identified as high yielding and most stable across environments.
A study was carried out to ascertain the effects some new maize varieties: Obatanpa (OB), Opeaburoo (OP), Honampa (HO), Aseda (AS), Tintim (TT), Owanwa (OW) and Odomfo (OD) on the growth performance and carcass traits of albino rats. Aseda, Opeaburoo and Tintim are all white varieties and have been described as ...
Morka is a common name given to the maize (Zea mays L.) variety with the pedigree UCB S1 C2 after its official release. It is an open pollinated variety developed by the Jimma Agricultural Research Center from UCB after two cycles of S1 recurrent selection. Morka means “competent” in Afan Oromo language given to ...
Antonio A. F. Garcia
Full Text Available In order to compare their relative efficiencies as markers and to find the most suitable marker for maize diversity studies we evaluated 18 inbred tropical maize lines using a number of different loci as markers. The loci used were: 774 amplified fragment length polymorphisms (AFLPs; 262 random amplified polymorphic DNAs (RAPDs; 185 restriction fragment length polymorphisms (RFLPs; and 68 simple sequence repeats (SSR. For estimating genetic distance the AFLP and RFLP markers gave the most correlated results, with a correlation coefficient of r = 0.87. Bootstrap analysis were used to evaluate the number of loci for the markers and the coefficients of variation (CV revealed a skewed distribution. The dominant markers (AFLP and RAPD had small CV values indicating a skewed distribution while the codominant markers gave high CV values. The use of maximum values of genetic distance CVs within each sample size was efficient in determining the number of loci needed to obtain a maximum CV of 10%. The number of RFLP and AFLP loci used was enough to give CV values of below 5%, while the SSRs and RAPD loci gave higher CV values. Except for the RAPD markers, all the markers correlated genetic distance with single cross performance and heterosis which showed that they could be useful in predicting single cross performance and heterosis in intrapopulation crosses for broad-based populations. Our results indicate that AFLP seemed to be the best-suited molecular assay for fingerprinting and assessing genetic relationships among tropical maize inbred lines with high accuracy.
Pan, Qingchun; Xu, Yuancheng; Li, Kun; Peng, Yong; Zhan, Wei; Li, Wenqiang; Li, Lin; Yan, Jianbing
Plant architecture is a key factor affecting planting density and grain yield in maize ( Zea mays ). However, the genetic mechanisms underlying plant architecture in diverse genetic backgrounds have not been fully addressed. Here, we performed a large-scale phenotyping of 10 plant architecture-related traits and dissected the genetic loci controlling these traits in 10 recombinant inbred line populations derived from 14 diverse genetic backgrounds. Nearly 800 quantitative trait loci (QTLs) with major and minor effects were identified as contributing to the phenotypic variation of plant architecture-related traits. Ninety-two percent of these QTLs were detected in only one population, confirming the diverse genetic backgrounds of the mapping populations and the prevalence of rare alleles in maize. The numbers and effects of QTLs are positively associated with the phenotypic variation in the population, which, in turn, correlates positively with parental phenotypic and genetic variations. A large proportion (38.5%) of QTLs was associated with at least two traits, suggestive of the frequent occurrence of pleiotropic loci or closely linked loci. Key developmental genes, which previously were shown to affect plant architecture in mutant studies, were found to colocalize with many QTLs. Five QTLs were further validated using the segregating populations developed from residual heterozygous lines present in the recombinant inbred line populations. Additionally, one new plant height QTL, qPH3 , has been fine-mapped to a 600-kb genomic region where three candidate genes are located. These results provide insights into the genetic mechanisms controlling plant architecture and will benefit the selection of ideal plant architecture in maize breeding. © 2017 American Society of Plant Biologists. All Rights Reserved.
Intense artificial selection over the last 100 years has produced elite maize (Zea mays) inbred lines that combine to produce high-yielding hybrids. To further our understanding of how genome and transcriptome variation contribute to the production of high-yielding hybrids, we generated a draft geno...
Amir José Klein Werle
Full Text Available This study aimed to investigate the combining ability and heterotic effects on grain yield (GY, oil content (OC and crude protein (CP in tropical and temperate maize lines. Hybrids and inbred lines were evaluated in a complete diallel scheme without reciprocals, in two experiments in randomized blocks with three replications. The partitioning of the sum of squares for general (GCA and specific (SCA combining ability indicated that both additive and non-additive effects were involved in the genetic control of the studied traits. The estimates of the quadratic components showed predominance of non-additive genetic effects in the trait control. However, for OC and CP, the non-additive effect had a clearly negative influenc
Full Text Available Boron (B deficiency in maize can result in barren cobs attributed to silks being nonreceptive which is particularly important for the female parent in seed production. The objectives of this study were 1 to investigate genotypic differences among nine female inbred lines used in seed production for B concentration in ear-leaf and grain, as well as for grain yield and moisture in a three-year experiment (2006-2008 and 2 to determine response and relations among the traits when four of the female inbred lines are treated by foliar boron fertilization - three times in 10-days interval with 0.5% Solubor solution (17.5% B during one growing season (2008. The investigations were performed on Experimental field of Agricultural Institute Osijek, (soil type: eutrical cambisol. Highly significant differences among the nine female inbred lines were detected for B concentration in ear-leaf (from 14.7 to 46.7 mg B kg-1 and grain (from 1.20 to 2.06 mg B kg-1 as well as for grain yield (from 3.33 to 4.83 t ha-1 and grain moisture (from 14.7% to 26.6%. However, there were also significant effects of growing season and the genotype by environment interaction for all four traits. Positive and moderate correlations were found between the boron status in plant and grain yield. Although B concentrations were considerably increased by foliar boron fertilization (averages 41.7 and 125.3 mg B kg-1 in leaves, 1.79 and 2.80 mg B kg-1 in grain, for control and fertilization, respectively, in general grain yield differences among treatments were non-significant. (averages 5.21 and 5.15 t ha-1, respectively.
Full Text Available A long period of silk viability is critical for a good seed setting rate in maize (Zea mays L., especially for inbred lines and hybrids with a long interval between anthesis and silking. To explore the molecular mechanism of silk viability and its heterosis, three inbred lines with different silk viability characteristics (Xun928, Lx9801, and Zong3 and their two hybrids (Xun928×Zong3 and Lx9801×Zong3 were analyzed at different developmental stages by a proteomic method. The differentially accumulated proteins were identified by mass spectrometry and classified into metabolism, protein biosynthesis and folding, signal transduction and hormone homeostasis, stress and defense responses, and cellular processes. Proteins involved in nutrient (methionine and energy (ATP supply, which support the pollen tube growth in the silk, were important for silk viability and its heterosis. The additive and dominant effects at a single locus, as well as complex epistatic interactions at two or more loci in metabolic pathways, were the primary contributors for mid-parent heterosis of silk viability. Additionally, the proteins involved in the metabolism of anthocyanins, which indirectly negatively regulate local hormone accumulation, were also important for the mid-parent heterosis of silk viability. These results also might imply the developmental dependence of heterosis, because many of the differentially accumulated proteins made distinct contributions to the heterosis of silk viability at specific developmental stages.
field experiment was conducted at the Kano University of Science and Technology Wudil teaching and research farm during the 2010 and 2011 rainy seasons. Five varieties of maize were studied to estimate components of genetic variance and heritability of some quantitative characters that might exist among them, under ...
Cho, Myeong-Je; Wu, Emily; Kwan, Jackie; Yu, Maryanne; Banh, Jenny; Linn, Wutt; Anand, Ajith; Li, Zhi; TeRonde, Susan; Register, James C; Jones, Todd J; Zhao, Zuo-Yu
An improved Agrobacterium -mediated transformation protocol is described for a recalcitrant commercial maize elite inbred with optimized media modifications and AGL1. These improvements can be applied to other commercial inbreds. This study describes a significantly improved Agrobacterium-mediated transformation protocol in a recalcitrant commercial maize elite inbred, PHR03, using optimal co-cultivation, resting and selection media. The use of green regenerative tissue medium components, high copper and 6-benzylaminopurine, in resting and selection media dramatically increased the transformation frequency. The use of glucose in resting medium further increased transformation frequency by improving the tissue induction rate, tissue survival and tissue proliferation from immature embryos. Consequently, an optimal combination of glucose, copper and cytokinin in the co-cultivation, resting and selection media resulted in significant improvement from 2.6 % up to tenfold at the T0 plant level using Agrobacterium strain LBA4404 in transformation of PHR03. Furthermore, we evaluated four different Agrobacterium strains, LBA4404, AGL1, EHA105, and GV3101 for transformation frequency and event quality. AGL1 had the highest transformation frequency with up to 57.1 % at the T0 plant level. However, AGL1 resulted in lower quality events (defined as single copy for transgenes without Agrobacterium T-DNA backbone) when compared to LBA4404 (30.1 vs 25.6 %). We propose that these improvements can be applied to other recalcitrant commercial maize inbreds.
Full Text Available Diallel mating design experiment with reciprocal crosses was used to determine combining abilities of five maize inbred lines and their hybrid combinations for grain yield, ear length, ear diameter, number of kernel rows per ear, number of kernels per row in 2005. and 2006. year. GCA and SCA significant values were observed for all traits under study in both years. GCA/SCA relation showed that dominant gene effect had prevalent influence in the inheritance of grain yield, ear length and ear diameter. Additive gene effect had larger importance in the inheritance of number of kernel rows per ear. NS-1445 inbred line showed best GCA effect for grain yield, ear length and number of kernels per row, but worst GCA effect for number of kernel rows per ear. Best GCA effect for ear diameter achieved inbred line F-7R. Line BL-47 showed best GCA effect for number of kernel rows per ear in both years, but also the worst GCA effect for grain yield and number of kernels per row. Hybrid combination NS-1445 x BL-47 showed largest SCA effect for grain yield in both years and also showed, like hybrid combination F-7R x NS-1445, significant SCA effects for all other traits, except ear diameter. This cross also proved that hybrid combinations that include one parent with good GCA effect and the other parent with bad GCA effect can have very successful performance. It will be useful during selection material testing, to keep also genotypes which show bad GCA effect, but have phenotypic favorable trait values. Reciprocity effect was significant for SCA effects of all traits but ear diameter. It is the conformation of involvement of plasmagenes in maize quantitative traits inheritance. The largest reciprocity effect for grain yield achieved F-7R x BL-47 in both years. Significantly higher grain yield in this hybrid combination was achieved when line F-7R was used as a female parent and significantly higher number of kernel rows per ear was achieved when line BL-47 was
K. V. Derkach
Full Text Available In connection with the necessity of bringing elite maize inbreds of the Lancaster germplasm group, which have potential for cultivation in Ukraine, into the system of genetic tranformation, the aim of this investigation is to identify the ability of maize inbreds of this group to regenerate by direct organogenesis and to determine the optimal mineral basis for their nutritional environment using segments of the node area of shoots. As explantats we used sterile 4-day old seedlings of 4 maize inbreds of Lancaster germplasm and model inbred Chi31 exotic germplasm. The seedlings were obtained by germination of sterile seeds in Petri dishes between two layers of moist sterile filter paper at a temperature of 27 ºC in dark conditions. A single 1 cmlong segment was cut from each from each seedling, running from 0.5 cmbefore the node to 0.5 cmafter the node. A cut was made in each segment of the node in order to create a wounded surface. Explantats were planted in a nutrient environment with mineral bases of MS or N6, modified by the addition of 10 mg/l silver nitrate, 100 mg/l casein hydrolyzate, 690 mg/l L-proline, 30 g/l sucrose, 1.0 mg/l 2,4-dychlorphenoksiacetic acid and 0,1 mg/l abscisic acid. Cultivation was carried out at 25–27 ºC in the light. Direct hemogenesis in this environment on the 14th day of cultivation in vitro reached 100% for each line. This meant that all researched lines of Lancaster germplasm and the model line showed a high capacity for direct regeneration through direct hemogenesis, which does not depend on the composition of the mineral content of their nutritional environment. Callus formation was observed in all genotypes on the 14th day of cultivation in vitro and the extent of its formation increased during the following month of cultivation. The callus formation was observed only at the site of the wounded surface. The calluses were transparent. Although green areas appeared in these calluses, they were
Akiyama, Hiroshi; Sakata, Kozue; Kondo, Kazunari; Tanaka, Asako; Liu, Ming S; Oguchi, Taichi; Furui, Satoshi; Kitta, Kazumi; Hino, Akihiro; Teshima, Reiko
In many countries, the labeling of grains and feed- and foodstuffs is mandatory if the genetically modified organism (GMO) content exceeds a certain level of approved GM varieties. The GMO content in a maize sample containing the combined-trait (stacked) GM maize as determined by the currently available methodology is likely to be overestimated. However, there has been little information in the literature on the mixing level and varieties of stacked GM maize in real sample grains. For the first time, the GMO content of non-identity-preserved (non-IP) maize samples imported from the United States has been successfully determined by using a previously developed individual kernel detection system coupled to a multiplex qualitative PCR method followed by multichannel capillary gel electrophoresis system analysis. To clarify the GMO content in the maize samples imported from the United States, determine how many stacked GM traits are contained therein, and which GM trait varieties frequently appeared in 2005, the GMO content (percent) on a kernel basis and the varieties of the GM kernels in the non-IP maize samples imported from the United States were investigated using the individual kernel analysis system. The average (+/-standard deviation) of the GMO contents on a kernel basis in five non-IP sample lots was determined to be 51.0+/-21.6%, the percentage of a single GM trait grains was 39%, and the percentage of the stacked GM trait grains was 12%. The MON810 grains and NK603 grains were the most frequent varieties in the single GM traits. The most frequent stacked GM traits were the MON810xNK603 grains. In addition, the present study would provide the answer and impact for the quantification of GM maize content in the GM maize kernels on labeling regulation.
Liliane N. Tandzi
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
Tian, Hong-Li; Wang, Feng-Ge; Zhao, Jiu-Ran; Yi, Hong-Mei; Wang, Lu; Wang, Rui; Yang, Yang; Song, Wei
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.
Xu, Su-Xia; Liu, Jie; Liu, Gong-She
A challenge to maize breeders is to predict and identify inbred lines that can produce highly heterotic hybrids precisely. In the present study we surveyed the genetic diversity among 15 elite inbred lines of maize in China with SSR markers and assessed the relationship between SSR marker and hybrid yield/yield heterosis in a diallel set of 105 crosses. Forty-three SSR primers selected from all sixty-three primers gave stable profiles amplified in the sample of 15 inbred lines, which could clearly resolve on 4% metaphor agarose gel. The average number of alleles per SSR locus was 4.44 with a range from 2 to 9. The polymorphism information content (PIC) for the SSR loci varied from 0.28 to 0.81 with a mean of 0.6281. Genetic similarity (GS) among 15 lines was estimated with 191 alleles identified as raw data, the Nei's coefficient of GS ranged from 0.492 for 478 vs HZ4 up to 0.745 for E28 to ZH64 with a mean of 0.619. The cluster diagram based upon the SSR data grouped the 15 lines into families consistent with the yield heterotic response of these. Genetic distance (GD) based on SSR data was significantly correlated with hybrid yield/yield heterosis, the correlation coefficient (r) being 0.5432 and 0.4271 in 1999 and 0.4305 and 0.3614 in 1998 field test, respectively, whereas the determination coefficient (r2) was lower. The correlation between GD based on SSR data and hybrid yield/yield heterosis changed alone with the difference of number and pedigree relationship among parents that were used in this study. SSR makers showed high polymorphism and could be used to assess the relationship between inbred lines of maize, but it was difficult to predict the yield heterosis of maize.
Eight maize (Zea mays L.) inbred lines and their single cross hybrids were grown for one year under field conditions near Osijek. The ear-leaf was taken in the tasseling stage and analysed for Ca and Mg percentage. Parental effects on ear-leaf content of Ca and Mg were very high. The hybrids of line C103 had low mean percentages of ear-leaf Ca and Mg while the hybrids of line Os64 had high mean percentages.
Radenović Čedomir N.
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.
Fernando Lisboa Guedes
Full Text Available The objective of our study was to characterize and determine the patterns of genetic control in relation to tolerance and efficiency of nitrogen use by means of a complete diallel cross involving contrasting inbred progenies of tropical maize based on a univariate approach within the perspective of a multivariate mixed model. Eleven progenies, previously classified regarding the tolerance and responsiveness to nitrogen, were crossed in a complete diallel cross. Fifty-five hybrids were obtained. The hybrids and the progenies were evaluated at two different nitrogen levels, in two locations. The grain yield was measured as well as its yield components. The heritability values between the higher and lower nitrogen input environment did not differ among themselves. It was observed that the general combining ability values were similar for both approaches univariate and multivariate, when it was analyzed within each location and nitrogen level. The estimate of variance of the specific combining ability was higher than general combining ability estimate and the ratio between them was 0.54. The univariate and multivariate approaches are equivalent in experiments with good precision and high heritability. The nonadditive genetic effects exhibit greater quantities than the additive genetic effects for the genetic control of nitrogen use efficiency.
Guedes, Fernando Lisboa; Diniz, Rafael Parreira; Balestre, Marcio; Ribeiro, Camila Bastos; Camargos, Renato Barbosa; Souza, João Cândido
The objective of our study was to characterize and determine the patterns of genetic control in relation to tolerance and efficiency of nitrogen use by means of a complete diallel cross involving contrasting inbred progenies of tropical maize based on a univariate approach within the perspective of a multivariate mixed model. Eleven progenies, previously classified regarding the tolerance and responsiveness to nitrogen, were crossed in a complete diallel cross. Fifty-five hybrids were obtained. The hybrids and the progenies were evaluated at two different nitrogen levels, in two locations. The grain yield was measured as well as its yield components. The heritability values between the higher and lower nitrogen input environment did not differ among themselves. It was observed that the general combining ability values were similar for both approaches univariate and multivariate, when it was analyzed within each location and nitrogen level. The estimate of variance of the specific combining ability was higher than general combining ability estimate and the ratio between them was 0.54. The univariate and multivariate approaches are equivalent in experiments with good precision and high heritability. The nonadditive genetic effects exhibit greater quantities than the additive genetic effects for the genetic control of nitrogen use efficiency.
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 ...
Hauck, Andrew L; Novais, Joana; Grift, Tony E; Bohn, Martin O
The mature root system is a vital plant organ, which is critical to plant performance. Commercial maize (Zea mays L.) breeding has resulted in a steady increase in plant performance over time, along with noticeable changes in above ground vegetative traits, but the corresponding changes in the root system are not presently known. In this study, roughly 2500 core root systems from field trials of a set of 10 diverse elite inbreds formerly protected by Plant Variety Protection plus B73 and Mo17 and the 66 diallel intercrosses among them were evaluated for root traits using high throughput image-based phenotyping. Overall root architecture was modeled by root angle (RA) and stem diameter (SD), while root complexity, the amount of root branching, was quantified using fractal analysis to obtain values for fractal dimension (FD) and fractal abundance (FA). For each trait, per se line effects were highly significant and the most important contributor to trait performance. Mid-parent heterosis and specific combining ability was also highly significant for FD, FA, and RA, while none of the traits showed significant general combining ability. The interaction between the environment and the additive line effect was also significant for all traits. Within the inbred and hybrid generations, FD and FA were highly correlated (rp ≥ 0.74), SD was moderately correlated to FD and FA (0.69 ≥ rp ≥ 0.48), while the correlation between RA and other traits was low (0.13 ≥ rp ≥ -0.40). Inbreds with contrasting effects on complexity and architecture traits were observed, suggesting that root complexity and architecture traits are inherited independently. A more comprehensive understanding of the maize root system and the way it interacts with the environment will be useful for defining adaptation to nutrient acquisition and tolerance to stress from drought and high plant densities, critical factors in the yield gains of modern hybrids.
Ganie, Arshid Hussain; Yousuf, Peerzada Yasir; Ahad, Amjid; Pandey, Renu; Ahmad, Sayeed; Aref, Ibrahim M; Noor, Jewel Jameeta; Iqbal, Muhammad
Maize (Zea mays L.) is a multipurpose crop, which is immensely used worldwide for its nutritional as well as medicinal properties. This study evaluates the effect of varying concentrations of nitrogen (N) on accumulation of phenolic acids and antioxidant activity in different maize cultivars, including inbreds, hybrids and a composite, which were grown in natural light under controlled temperature (30°C/20°C D/N) and humidity (80%), with sufficient (4.5mM) and low (0.05mM) nitrogen supply. Seeds of different cultivars were powdered and extracted in a methanol:water (80:20) mixture through reflux at 60-75°C, and the extracts obtained were subjected to high performance thin layer chromatography (HPTLC), using ethyl acetate: acetic acid: formic acid: water (109:16:12:31) solvent system for the separation of phenolic acids. Antioxidant activity of the extracts was determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and H2O2-scavenging activity assays. At sufficient nitrogen condition, the contents of different phenolic acids were higher in the composite cultivar (8.7 mg g-1 d.wt. in gallic acid to 39.3 mg g-1 d.wt. in cinnamic and salicylic acids) than in inbreds and hybrids. Under low nitrogen condition, the phenolic acids contents declined significantly in inbreds and hybrids, but remained almost unaffected in the composite. The antioxidant activity was also the maximum in the composite, and declined similarly as phenolic acids under low nitrogen supply, showing a significant reduction in inbreds and hybrids only. Therefore, the maize composite has a potential for being used as a nutraceutical in human-health sector.
Brodmann, Peter D; Ilg, Evelyn C; Berthoud, Hélène; Herrmann, Andre
Quantitative detection methods are needed for enforcement of the recently introduced labeling threshold for genetically modified organisms (GMOs) in food ingredients. This labeling threshold, which is set to 1% in the European Union and Switzerland, must be applied to all approved GMOs. Four different varieties of maize are approved in the European Union: the insect-resistant Bt176 maize (Maximizer), Btl 1 maize, Mon810 (YieldGard) maize, and the herbicide-tolerant T25 (Liberty Link) maize. Because the labeling must be considered individually for each ingredient, a quantitation system for the endogenous maize content is needed in addition to the GMO-specific detection systems. Quantitative real-time polymerase chain reaction detection methods were developed for the 4 approved genetically modified maize varieties and for an endogenous maize (invertase) gene system.
Mascher, Martin; Gerlach, Nina; Gahrtz, Manfred; Bucher, Marcel; Scholz, Uwe; Dresselhaus, Thomas
Maize (Zea mays) is the most widely grown crop species in the world and a classical model organism for plant research. The completion of a high-quality reference genome sequence and the advent of high-throughput sequencing have greatly empowered re-sequencing studies in maize. In this study, plants of maize inbred line B73 descended from two different sets of seed material grown for several generations either in the field or in the greenhouse were found to show a different growth phenotype and ionome under phosphate starvation conditions and moreover a different responsiveness towards mycorrhizal fungi of the species Glomus intraradices (syn: Rhizophagus irregularis). Whole genome re-sequencing of individuals from both sets and comparison to the B73 reference sequence revealed three cryptic introgressions on chromosomes 1, 5 and 10 in the line grown in the greenhouse summing up to a total of 5,257 single-nucleotide polymorphisms (SNPs). Transcriptome sequencing of three individuals from each set lent further support to the location of the introgression intervals and confirmed them to be fixed in all sequenced individuals. Moreover, we identified >120 genes differentially expressed between the two B73 lines. We thus have found a nearly-isogenic line (NIL) of maize inbred line B73 that is characterized by an altered growth phenotype under phosphate starvation conditions and an improved responsiveness towards symbiosis with mycorrhizal fungi. Through next-generation sequencing of the genomes and transcriptomes we were able to delineate exact introgression intervals. Putative de novo mutations appeared approximately uniformly distributed along the ten maize chromosomes mainly representing G:C -> A:T transitions. The plant material described in this study will be a valuable tool both for functional studies of genes differentially expressed in both B73 lines and for research on growth behavior especially in response to symbiosis between maize and mycorrhizal fungi.
Full Text Available Maize (Zea mays is the most widely grown crop species in the world and a classical model organism for plant research. The completion of a high-quality reference genome sequence and the advent of high-throughput sequencing have greatly empowered re-sequencing studies in maize. In this study, plants of maize inbred line B73 descended from two different sets of seed material grown for several generations either in the field or in the greenhouse were found to show a different growth phenotype and ionome under phosphate starvation conditions and moreover a different responsiveness towards mycorrhizal fungi of the species Glomus intraradices (syn: Rhizophagus irregularis. Whole genome re-sequencing of individuals from both sets and comparison to the B73 reference sequence revealed three cryptic introgressions on chromosomes 1, 5 and 10 in the line grown in the greenhouse summing up to a total of 5,257 single-nucleotide polymorphisms (SNPs. Transcriptome sequencing of three individuals from each set lent further support to the location of the introgression intervals and confirmed them to be fixed in all sequenced individuals. Moreover, we identified >120 genes differentially expressed between the two B73 lines. We thus have found a nearly-isogenic line (NIL of maize inbred line B73 that is characterized by an altered growth phenotype under phosphate starvation conditions and an improved responsiveness towards symbiosis with mycorrhizal fungi. Through next-generation sequencing of the genomes and transcriptomes we were able to delineate exact introgression intervals. Putative de novo mutations appeared approximately uniformly distributed along the ten maize chromosomes mainly representing G:C -> A:T transitions. The plant material described in this study will be a valuable tool both for functional studies of genes differentially expressed in both B73 lines and for research on growth behavior especially in response to symbiosis between maize and
Nass Luciano Lourenço
Full Text Available For tropical areas like Brazil, genotype x environment interaction is an important source of variation. Our objectives were to examine the combining abilities and their interaction with environments in ten selected maize (Zea mays L. inbred lines in diallel crosses and to identify candidates for promising hybrid combinations. Crosses and checks were evaluated through a 7 x 7 triple lattice design at three locations during the 1984/85 season. Several agronomic traits were evaluated, but here only data on ear yield are discussed. Yield data were adjusted for stand variation (correction to 50 plants per plot and grain moisture (15.5%. Data for ear yield were analysed using an adaptation of Griffing?s method IV for complete diallel crosses, and experiments were repeated in several environments. The means of the crosses over all environments ranged from 6.6 t/ha to 10.3 t/ha. The combining ability analysis of diallel data across environments showed highly significant (P<0.01 effects for environment, general combining ability (GCA, specific combining ability (SCA, and GCA x environment interaction. The SCA x environment interaction was not significant. Results showed that both GCA and SCA were important for this diallel cross. Considering the 13 hybrids that showed higher yields than the commercial hybrid controls, contributions by GCA and SCA effects were 56% and 44%, respectively. On the other hand, selecting only the best five hybrids, SCA effects were always more important than GCA effects for each environment and over all environments.
Holding, David R.
Quality protein maize (QPM) is a high lysine-containing corn that is based on genetic modification of the opaque2 (o2) mutant. In QPM, modifier genes convert the starchy endosperm of o2 to the vitreous phenotype of wild type maize. There are multiple, unlinked o2 modifier loci (Opm) in QPM and their nature and mode of action are unknown. We previously identified seven Opm QTLs and characterized 16 genes that are differentially up-regulated at a significant level in K0326Y QPM, compared to the starchy endosperm mutant W64Ao2. In order to further characterize these Opm QTLs and the genes up-regulated in K0326Y QPM, we created a population of 314 recombinant inbred lines (RILs) from a cross between K0326Y QPM and W64Ao2. The RILs were characterized for three traits associated with endosperm texture: vitreousness, density and hardness. Genetic linkage analysis of the RIL population confirmed three of the previously identified QTLs associated with o2 endosperm modification in K0326Y QPM. Many of the genes up-regulated in K0326Y QPM showed substantially higher levels of expression in vitreous compared with opaque RILs. These included genes associated with the upstream regulation of the ethylene response pathway, and a gene encoding a regulatory subunit of pyrophosphate-dependent fructose-6-phosphate 1-phosphotransferase, an adaptive enzyme of the glycolytic pathway. © 2010 Springer-Verlag.
Yudin, B.F.; Lukina, L.A.
Three generations of six mutants obtained by γ- and x-irradiation of seeds of highly apomictic variety of 38 chromosome maize-tripsacum hybrid have been studied. Radiomutants detected in M 2 preserved the mother type and constance in M 3 and M 4 . One of the mutants, as an exception, manifested somatic splitting, which resulted in the appearance of a new apomictic clone. Irradiation and mutation in some cases were accompanied by the appearance of seedlings with high chromosome numbers in mutant posterity, including apomicts with doubled number of chromosomes, as well as the increase of total part of sexual reproduction; the latter circumstance is considered as a result of modificator balance change caused by treatments. Doubling of chromosome number in 38-chromosome apomicts, according to preliminary data, does not affect significantly the way of reproduction; 76-chromosome forms preserve a high degree of a regular apomixis
nutritional compositions. NY Abba, BC Echezona. Abstract. Maize weevils are known to be among the economically important insect pests of maize in Nigeria. They cause significant damage to maize grains in store. The objective of the study was to ...
Phosphorus and nitrogen deficiencies limit production of maize (Zea mays L.) in many soils of western Kenya. Considerable amount of work has been done on N nutrition of maize in the region. There is, however, paucity of information on which to base fertiliser P recommendations for increased maize production ...
Gordon, Stuart G; Lipps, Patrick E; Pratt, Richard C
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.
Full Text Available The study was carried out in the experimental filed of the Maize Research Institute, Zemun Polje, on calcareous chernozem in the period 2001-2003. The traits of two maize inbred lines (L1-FAO 400 and L2-FAO 600 were observed in dependence on the time of the nitrogen application (No-control without fertilizing; Nautumn - 60 kg P2O5 ha-1 and 60 kg K2O ha-1 applied in autumn (const + 100 kg N ha-1 (applied in autumn; Nspring - PK (const + 100 kg N ha-1 (applied in spring; N1/2 - PK (const + 100 kg N ha-1 (half of which was applied in autumn and the other half in spring; N1/2-PK (const 100 kg N ha-1 (1/3 of which was applied in autumn, 1/3 in spring and 1/3 through soil dressing; Nmin - PK (const + fertilizing in spring on the basis of the Nmin method, and forms of applied nitrogen: Urea (amide form KAN (ammonium-nitrate form and (NH42SO4 (ammonium form. The highest average yield was obtained by the use of Nmin method (3,486 kg ha-1, as well as, 100 kg N ha-1 applied in sprig (Nspring (3,337 kg ha-1, 100 kg N ha-1 applied in autumn and spring (N1/2 (3,020 kgha-1 and 100 kg N ha-1 applied in autumn, spring and soil dressing (N1/3 (3,005 kg ha-1 in the ammonium-nitrate form (KAN. The highest average seed yield of observed maize inbred lines (3,264 kg ha-1 was obtained by the application of ammonium-sulphate in the primary tillage (Nautumn. The use of the Nmin method (N ranging from 17 to 35 kg ha-1, in dependence on the soil mineral nitrogen content, especially in years with lower precipitation sums resulted in the highest increase in seed yield (39.2% of observed maize inbred lines in relation to the control.
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
Semagn, Kassa; Magorokosho, Cosmos; Vivek, Bindiganavile S; Makumbi, Dan; Beyene, Yoseph; Mugo, Stephen; Prasanna, B M; Warburton, Marilyn L
Knowledge of germplasm diversity and relationships among elite breeding materials is fundamentally important in crop improvement. We genotyped 450 maize inbred lines developed and/or widely used by CIMMYT breeding programs in both Kenya and Zimbabwe using 1065 SNP markers to (i) investigate population structure and patterns of relationship of the germplasm for better exploitation in breeding programs; (ii) assess the usefulness of SNPs for identifying heterotic groups commonly used by CIMMYT breeding programs; and (iii) identify a subset of highly informative SNP markers for routine and low cost genotyping of CIMMYT germplasm in the region using uniplex assays. Genetic distance for about 94% of the pairs of lines fell between 0.300 and 0.400. Eighty four percent of the pairs of lines also showed relative kinship values ≤ 0.500. Model-based population structure analysis, principal component analysis, neighbor-joining cluster analysis and discriminant analysis revealed the presence of 3 major groups and generally agree with pedigree information. The SNP markers did not show clear separation of heterotic groups A and B that were established based on combining ability tests through diallel and line x tester analyses. Our results demonstrated large differences among the SNP markers in terms of reproducibility, ease of scoring, polymorphism, minor allele frequency and polymorphic information content. About 40% of the SNPs in the multiplexed chip-based GoldenGate assays were found to be uninformative in this study and we recommend 644 of the 1065 for low to medium density genotyping in tropical maize germplasm using uniplex assays. There were high genetic distance and low kinship coefficients among most pairs of lines, clearly indicating the uniqueness of the majority of the inbred lines in these maize breeding programs. The results from this study will be useful to breeders in selecting best parental combinations for new breeding crosses, mapping population development
Full Text Available Abstract Background Knowledge of germplasm diversity and relationships among elite breeding materials is fundamentally important in crop improvement. We genotyped 450 maize inbred lines developed and/or widely used by CIMMYT breeding programs in both Kenya and Zimbabwe using 1065 SNP markers to (i investigate population structure and patterns of relationship of the germplasm for better exploitation in breeding programs; (ii assess the usefulness of SNPs for identifying heterotic groups commonly used by CIMMYT breeding programs; and (iii identify a subset of highly informative SNP markers for routine and low cost genotyping of CIMMYT germplasm in the region using uniplex assays. Results Genetic distance for about 94% of the pairs of lines fell between 0.300 and 0.400. Eighty four percent of the pairs of lines also showed relative kinship values ≤ 0.500. Model-based population structure analysis, principal component analysis, neighbor-joining cluster analysis and discriminant analysis revealed the presence of 3 major groups and generally agree with pedigree information. The SNP markers did not show clear separation of heterotic groups A and B that were established based on combining ability tests through diallel and line x tester analyses. Our results demonstrated large differences among the SNP markers in terms of reproducibility, ease of scoring, polymorphism, minor allele frequency and polymorphic information content. About 40% of the SNPs in the multiplexed chip-based GoldenGate assays were found to be uninformative in this study and we recommend 644 of the 1065 for low to medium density genotyping in tropical maize germplasm using uniplex assays. Conclusions There were high genetic distance and low kinship coefficients among most pairs of lines, clearly indicating the uniqueness of the majority of the inbred lines in these maize breeding programs. The results from this study will be useful to breeders in selecting best parental combinations
Weng, Jianfeng; Li, Bo; Liu, Changlin; Yang, Xiaoyan; Wang, Hongwei; Hao, Zhuanfang; Li, Mingshun; Zhang, Degui; Ci, Xiaoke; Li, Xinhai; Zhang, Shihuang
Kernel weight, controlled by quantitative trait loci (QTL), is an important component of grain yield in maize. Cytokinins (CKs) participate in determining grain morphology and final grain yield in crops. ZmIPT2, which is expressed mainly in the basal transfer cell layer, endosperm, and embryo during maize kernel development, encodes an isopentenyl transferase (IPT) that is involved in CK biosynthesis. The coding region of ZmIPT2 was sequenced across a panel of 175 maize inbred lines that are currently used in Chinese maize breeding programs. Only 16 single nucleotide polymorphisms (SNPs) and seven haplotypes were detected among these inbred lines. Nucleotide diversity (π) within the ZmIPT2 window and coding region were 0.347 and 0.0047, respectively, and they were significantly lower than the mean nucleotide diversity value of 0.372 for maize Chromosome 2 (P maize germplasm, with the most frequent favorable allele identified in subgroup PB (Partner B). These results showed that ZmIPT2, which is associated with kernel weight, was subjected to artificial selection during the maize breeding process. ZmIPT2-T had higher IPT activity than ZmIPT2-C, and this favorable allele for kernel weight could be used in molecular marker-assisted selection for improvement of grain yield components in Chinese maize breeding programs.
Ten inbred parents with varying resistance levels to Chilo partellus and Busseola fusca were crossed in a half diallel mating scheme to generate 45 F1 hybrids. The hybrids and five commercial checks were evaluated across four locations in Kenya under artificial and natural infestation in 2009. Genotype (G) by environment ...
Springer, Nathan M; Ying, Kai; Fu, Yan; Ji, Tieming; Yeh, Cheng-Ting; Jia, Yi; Wu, Wei; Richmond, Todd; Kitzman, Jacob; Rosenbaum, Heidi; Iniguez, A Leonardo; Barbazuk, W Brad; Jeddeloh, Jeffrey A; Nettleton, Daniel; Schnable, Patrick S
Following the domestication of maize over the past approximately 10,000 years, breeders have exploited the extensive genetic diversity of this species to mold its phenotype to meet human needs. The extent of structural variation, including copy number variation (CNV) and presence/absence variation (PAV), which are thought to contribute to the extraordinary phenotypic diversity and plasticity of this important crop, have not been elucidated. Whole-genome, array-based, comparative genomic hybridization (CGH) revealed a level of structural diversity between the inbred lines B73 and Mo17 that is unprecedented among higher eukaryotes. A detailed analysis of altered segments of DNA conservatively estimates that there are several hundred CNV sequences among the two genotypes, as well as several thousand PAV sequences that are present in B73 but not Mo17. Haplotype-specific PAVs contain hundreds of single-copy, expressed genes that may contribute to heterosis and to the extraordinary phenotypic diversity of this important crop.
Full Text Available Plant volatiles induced by insect feeding are known to attract natural enemies of the herbivores. Six maize inbred lines that showed distinctly different patterns of volatile emission in laboratory assays were planted in randomized plots in the Central Mexican Highlands to test their ability to recruit parasitic wasps under field conditions. The plants were artificially infested with neonate larvae of the fall armyworm Spodoptera frugiperda, and two of its main endoparasitoids, Campoletis sonorensis and Cotesia marginiventris, were released in the plots. Volatiles were collected from equally treated reference plants in the neighbourhood of the experimental field. The cumulative amount of 36 quantified volatile compounds determined for each line was in good accordance with findings from the laboratory; there was an almost 15-fold difference in total emission between the two extreme lines. We found significant differences among the lines with respect to the numbers of armyworms recovered from the plants, their average weight gain and parasitism rates. Average weight of the caterpillars was negatively correlated with the average total amount of volatiles released by the six inbred lines. However, neither total volatile emission nor any specific single compound within the blend could explain the differential parasitism rates among the lines, with the possible exception of (E-2-hexenal for Campoletis sonorensis and methyl salicylate for Cotesia marginiventris. Herbivore-induced plant volatiles and/or correlates thereof contribute to reducing insect damage of maize plants through direct plant defence and enhanced attraction of parasitoids, alleged indirect defence. The potential to exploit these volatiles for pest control deserves to be further evaluated.
Degen, Thomas; Bakalovic, Nenad; Bergvinson, David; Turlings, Ted C. J.
Plant volatiles induced by insect feeding are known to attract natural enemies of the herbivores. Six maize inbred lines that showed distinctly different patterns of volatile emission in laboratory assays were planted in randomized plots in the Central Mexican Highlands to test their ability to recruit parasitic wasps under field conditions. The plants were artificially infested with neonate larvae of the fall armyworm Spodoptera frugiperda, and two of its main endoparasitoids, Campoletis sonorensis and Cotesia marginiventris, were released in the plots. Volatiles were collected from equally treated reference plants in the neighbourhood of the experimental field. The cumulative amount of 36 quantified volatile compounds determined for each line was in good accordance with findings from the laboratory; there was an almost 15-fold difference in total emission between the two extreme lines. We found significant differences among the lines with respect to the numbers of armyworms recovered from the plants, their average weight gain and parasitism rates. Average weight of the caterpillars was negatively correlated with the average total amount of volatiles released by the six inbred lines. However, neither total volatile emission nor any specific single compound within the blend could explain the differential parasitism rates among the lines, with the possible exception of (E)-2-hexenal for Campoletis sonorensis and methyl salicylate for Cotesia marginiventris. Herbivore-induced plant volatiles and/or correlates thereof contribute to reducing insect damage of maize plants through direct plant defence and enhanced attraction of parasitoids, alleged indirect defence. The potential to exploit these volatiles for pest control deserves to be further evaluated. PMID:23112820
Zhang, Z X; Zhang, F D; Tang, W H; Pi, Y J; Zheng, Y L
Comprehensive complementary DNA (cDNA) library is a valuable resource for functional genomics. In this study, we set up a normalized cDNA library of Mo17 (MONL) by saturation hybridization with genomic DNA, which contained expressed genes of eight tissues and organs from inbred Mo17 of maize (Zea mays L.). In this library, the insert sizes range from 0.4 kb to 4 kb and the average size is 1.18 kb. 10.830 clones were spotted on nylon membrane to make a cDNA microarray. Randomly picked 300 clones from the cDNA library were sequenced. The cDNA microarry was hybridized with pooled tissue mRNA probes or housekeeping gene cDNA probes. The results showed the normalized cDNA library comprehensively includes tissue-specific genes in which 71% are unique ESTs (expressed sequence tags) based on the 300 sequences analyzed. Using BLAST program to compare the sequences against online nucleotide databases, 88% sequences were found in ZmDB or NCBI, and 12% sequences were not found in existing nucleotide databases. More than 73% sequences are of unknown function. The library could be extensively used in developing DNA markers, sequencing ESTs, mining new genes, identifying positional cloning and candidate gene, and developing microarrays in maize genomics research.
Sisay Diriba Lemessa
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.
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 ...
)), Dorke SR (early, NM), Abeleehi (intermediate, NM), Obatanpa (intermediate, quality protein maize) and Okomasa (late, NM), were sown at 2-week intervals from mid-May to last week of July in 1993 and 1994 at Nyankpala in the Guinea ...
Jul 9, 2001 ... mangrove, forest, southern guinea savanna, northern guinea savanna, sudanisahel savanna and acidiclalkaline soils (Table 3). The trials were evaluated in the major (June-. November) maize growing season in 1996. A randomised complete block design with four replications was used at each location for ...
Zhou, Zhiqiang; Zhang, Chaoshu; Zhou, Yu; Hao, Zhuanfang; Wang, Zhenhua; Zeng, Xing; Di, Hong; Li, Mingshun; Zhang, Degui; Yong, Hongjun; Zhang, Shihuang; Weng, Jianfeng; Li, Xinhai
Plant architecture attributes, such as plant height, ear height, and internode number, have played an important role in the historical increases in grain yield, lodging resistance, and biomass in maize (Zea mays L.). Analyzing the genetic basis of variation in plant architecture using high density QTL mapping will be of benefit for the breeding of maize for many traits. However, the low density of molecular markers in existing genetic maps has limited the efficiency and accuracy of QTL mapping. Genotyping by sequencing (GBS) is an improved strategy for addressing a complex genome via next-generation sequencing technology. GBS has been a powerful tool for SNP discovery and high-density genetic map construction. The creation of ultra-high density genetic maps using large populations of advanced recombinant inbred lines (RILs) is an efficient way to identify QTL for complex agronomic traits. A set of 314 RILs derived from inbreds Ye478 and Qi319 were generated and subjected to GBS. A total of 137,699,000 reads with an average of 357,376 reads per individual RIL were generated, which is equivalent to approximately 0.07-fold coverage of the maize B73 RefGen_V3 genome for each individual RIL. A high-density genetic map was constructed using 4183 bin markers (100-Kb intervals with no recombination events). The total genetic distance covered by the linkage map was 1545.65 cM and the average distance between adjacent markers was 0.37 cM with a physical distance of about 0.51 Mb. Our results demonstrated a relatively high degree of collinearity between the genetic map and the B73 reference genome. The quality and accuracy of the bin map for QTL detection was verified by the mapping of a known gene, pericarp color 1 (P1), which controls the color of the cob, with a high LOD value of 80.78 on chromosome 1. Using this high-density bin map, 35 QTL affecting plant architecture, including 14 for plant height, 14 for ear height, and seven for internode number were detected
Bøhn, Thomas; Primicerio, Raul; Hessen, Dag O; Traavik, Terje
Genetically modified (GM) maize expressing the Bt-toxin Cry1Ab (Bt-maize) was tested for effects on survival, growth, and reproduction of the water flea Daphnia magna, a crustacean arthropod commonly used as a model organism in ecotoxicological studies. In three repeated experiments, D. magna were fed 100% ground maize in suspension, using either GM or isogenic unmodified (UM) maize. D. magna fed GM-maize showed a significantly reduced fitness performance: The mortality was higher, a lower proportion of females reached sexual maturation, and the overall egg production was lower compared to D. magna fed UM isogenic maize. We conclude that the tested variety of Bt-maize and its UM counterpart do not have the same quality as food sources for this widely used model organism. The combination of a reduced fitness performance combined with earlier onset of reproduction of D. magna fed Bt-maize indicates a toxic effect rather than a lower nutritional value of the GM-maize.
Yue, Haiwang; Chen, Shuping; Bu, Junzhou; Wei, Jianwei; Peng, Haicheng; Li, Yuan; Li, Chunjie; Xie, Junliang
Drought is a serious threat to maize production in Hebei province. Planting drought resistant maize varieties is an effective measure to solve drought in arid and less rain areas. Drought resistance in maize is controlled by many genes, and multiple indexes should be used for comprehensive evaluation (Campos H et al.2004). In the arid rain shed, using 34 maize varieties to promote crop production compared to the drought resistance test. The experiment was conducted with two treatments of drought stress (irrigation only at seedling stage) and normal irrigation, and 12 agronomic traits related to drought resistance of maize were determined. The results showed that drought had significant effects on maize yield and main agronomic characters. Under drought stress, plant height, ear length, bare tip, ear row number, row grains, 1000-kernel weight, ASI index can be used as identification index of drought resistance of maize in different period. The results indicated that the variety with strong drought resistance is Zhongdi175, the worst drought resistance is Woyu964.
Full Text Available Huitlacoche is the Aztecs name given to the smut galls on ears of maize caused by the pathogenic plant fungus Ustilago maydis [(DC Corda.]. It is known as maize mushroom, and it has been considered a delicacy and in Mesoamerica. The aim of the present study was to determine the responses of some maize varieties to the growth of the fungus in order to evaluate the prospect production of these smutty ears as a maize mushroom. A 2-year study was conducted in the Mediterranean region of Turkey in 2010 and 2011. Inoculations were performed by injecting inoculum into the ear through the silk channel of plants in plots. Each treatment had control plots. Average ear-gall (huitlacoche severity and incidence of all the varieties were at the rates of 4.0 and 41.6%, respectively. However, the highest severity of ear-gall (6.5 and incidence (60.6% were found in Karadeniz Yıldızı flint maize variety; colossal smutty ears were formed in the maize cultivars. This study showed that certain maize cultivars (flint corn and dent corn can be used efficiently in the production of huitlacoche.
Zeng, Di; Alwang, Jeffrey; Norton, George; Jaleta, Moti; Shiferaw, Bekele; Yirga, Chilot
The lack of land ownership can discourage agricultural technology adoption, yet there is scarce evidence of the impact of land rental contracts on the adoption of improved crop varieties in developing countries. The current study investigates such impact using a nationally representative survey of Ethiopian maize farmers. In contrast to many previous studies, we show in a simple model that cash-renters are as likely to adopt improved maize varieties as owner-operators, while sharecroppers are more likely to adopt given that such varieties are profitable. Empirical analysis reveals a significant impact of sharecropping on improved maize variety adoption, and no significant impact from cash-rental, lending support to the above hypotheses. These results imply that improvements in land rental markets can potentially enhance household welfare through crop variety adoption in agrarian economies where land sales markets are incomplete or missing.
A quality protein maize (QPM) hybrid programme was started in 1991 to develop and promote high and stableyielding QPM hybrids to increase production of nutritionally superior maize varieties in Ghana. Six 3- way QPM hybrids developed from inbred lines originating from germplasm of the International Centre for Maize
Darracq, Aude; Vitte, Clémentine; Nicolas, Stéphane; Duarte, Jorge; Pichon, Jean-Philippe; Mary-Huard, Tristan; Chevalier, Céline; Bérard, Aurélie; Le Paslier, Marie-Christine; Rogowsky, Peter; Charcosset, Alain; Joets, Johann
Maize is well known for its exceptional structural diversity, including copy number variants (CNVs) and presence/absence variants (PAVs), and there is growing evidence for the role of structural variation in maize adaptation. While PAVs have been described in this important crop species, they have been only scarcely characterized at the sequence level and the extent of presence/absence variation and relative chromosomal landscape of inbred-specific regions remain to be elucidated. De novo genome sequencing of the French F2 maize inbred line revealed 10,044 novel genomic regions larger than 1 kb, making up 88 Mb of DNA, that are present in F2 but not in B73 (PAV). This set of maize PAV sequences allowed us to annotate PAV content and to analyze sequence breakpoints. Using PAV genotyping on a collection of 25 temperate lines, we also analyzed Linkage Disequilibrium in PAVs and flanking regions, and PAV frequencies within maize genetic groups. We highlight the possible role of MMEJ-type double strand break repair in maize PAV formation and discover 395 new genes with transcriptional support. Pattern of linkage disequilibrium within PAVs strikingly differs from this of flanking regions and is in accordance with the intuition that PAVs may recombine less than other genomic regions. We show that most PAVs are ancient, while some are found only in European Flint material, thus pinpointing structural features that may be at the origin of adaptive traits involved in the success of this material. Characterization of such PAVs will provide useful material for further association genetic studies in European and temperate maize.
Gupta, D; Kovács, I; Gáspár, L
Diallel cross hybrids obtained by crossing six opaque-2 (o 2) converted inbred lines were compared with a similar series of crosses made between the analogous normal inbred lines together with the parents, for a number of protein quality and oil traits. The results obtained show that there is only a minor decrease in percent protein or yield of protein per hectare caused by the presence of the o 2 gene in recessive homozygous condition, compared with its normal counterpart. On the other hand, percent lysine in the whole kernel, lysine yield per hectare and percent lysine in protein are increased by 53, 45 and 55 percent, respectively, in the o 2 inbred lines and hybrids compared with their normal analogues. Percent oil and oil yield remain almost unaltered by the presence or absence of the o 2 gene. As well as lysine, the content of other amino acids, such as aspartic acid, arginine, glycine, threonine, valine and histidine are also, in general, increased by the presence of the o 2 gene in recessive homozygous condition.The results obtained have shown that a number of correlation coefficients between the protein quality traits and yield components related to kernel characteristics are negative and significant, especially in the presence of the o 2 gene in recessive homozygous condition. Only two correlation coefficients have been found that could be used with advantage by opaque-2 maize breeders. They are a stronger positive correlation of percent protein with percent lysine, and lysine yield per hectare with 1000 grain weight, in o 2 maize than in normal maize.The results presented here also show that there is more heterotic dilution in the o 2 hybrids than in the normal analogues for traits like percent protein, percent lysine (whole kernel basis) and percent lysine in protein. It has been observed that the inbred lines with the o 2 gene in recessive homozygous condition and a superior protein quality tend to produce hybrids of superior quality.
Improved open-pollinated varieties (OPVs) have been developed and released for commercial production in maize growing areas of Ethiopia. However, the dissemination of these improved varieties is limited because of a low level of interest of seed producers in the production and marketing of OPV seed.
Full Text Available MicroRNA-mediated gene regulation plays a crucial role in controlling drought tolerance. In the present investigation, 13 drought-associated miRNA families consisting of 65 members and regulating 42 unique target mRNAs were identified from drought-associated microarray expression data in maize and were subjected to structural and functional characterization. The largest number of members (14 was found in the zma-miR166 and zma-miR395 families, with several targets. However, zma-miR160, zma-miR390, zma-miR393, and zma-miR2275 each showed a single target. Twenty-three major drought-responsive cis-regulatory elements were found in the upstream regions of miRNAs. Many drought-related transcription factors, such as GAMYB, HD-Zip III, and NAC, were associated with the target mRNAs. Furthermore, two contrasting subtropical maize genotypes (tolerant: HKI-1532 and sensitive: V-372 were used to understand the miRNA-assisted regulation of target mRNA under drought stress. Approximately 35 and 31% of miRNAs were up-regulated in HKI-1532 and V-372, respectively. The up-regulation of target mRNAs was as high as 14.2% in HKI-1532 but was only 2.38% in V-372. The expression patterns of miRNA-target mRNA pairs were classified into four different types: Type I- up-regulation, Type II- down-regulation, Type III- neutral regulation, and Type IV- opposite regulation. HKI-1532 displayed 46 Type I, 13 Type II, and 23 Type III patterns, whereas V-372 had mostly Type IV interactions (151. A low level of negative regulations of miRNA associated with a higher level of mRNA activity in the tolerant genotype helped to maintain crucial biological functions such as ABA signaling, the auxin response pathway, the light-responsive pathway and endosperm expression under stress conditions, thereby leading to drought tolerance. Our study identified candidate miRNAs and mRNAs operating in important pathways under drought stress conditions, and these candidates will be useful in the
in order to incorporate their preferences in se- lection of varieties in the breeding programme as this may increase likelihood of adoption of the varieties, especially where the research di- rectly affects their livelihoods as suggested by other researchers (Ceccarelli et al., 2001; Jal- leta, 2004). According to Selener (1997) re-.
Terler, Georg; Gruber, Leonhard; Knaus, Wilhelm Friedrich
The nutritive value of whole crop forage maize is influenced by the proportion of ears and stover in the whole crop and by the nutrient composition and digestibility characteristics of the plant parts. An experiment investigating the impact of variety, harvest date and year on the nutritive value of ensiled maize ears was carried out in three consecutive years (2007, 2008 and 2010). Nine different maize varieties were harvested at three different maturity stages (50, 55 and 60% dry matter (DM) content in the ears). After harvest, ears and stover were ensiled separately and afterwards nutrient composition and ruminal nutrient degradability (organic matter (OM), crude protein (CP) and non-fibre carbohydrates (NFC)) were analysed. Variety had a significant influence on content of CP and effective ruminal degradability (ED) of OM at low passage rates, whereas ED of CP and NFC was not affected by variety. In contrast, harvest date and year significantly influenced nutrient composition and ruminal degradability of ensiled maize ears. The content of NFC increased and the content of fibre components as well as ED of OM, CP and NFC declined with processing maturity of the maize plants. At a passage rate of 5% h -1 , ED of OM declined from 75.9% to 68.4%, ED of CP from 82.5% to 73.8% and ED of NFC from 88.0% to 82.3% between the early and late harvest date. The results of this study indicate that the nutrient composition and ruminal degradability of ensiled maize ears are affected mainly by maturity stage at harvest and by year, whereas variety has only little influence.
Brusamarello-Santos, Liziane Cristina; Gilard, Françoise; Brulé, Lenaïg; Quilleré, Isabelle; Gourion, Benjamin; Ratet, Pascal; Maltempi de Souza, Emanuel; Lea, Peter J; Hirel, Bertrand
Maize roots can be colonized by free-living atmospheric nitrogen (N2)-fixing bacteria (diazotrophs). However, the agronomic potential of non-symbiotic N2-fixation in such an economically important species as maize, has still not been fully exploited. A preliminary approach to improve our understanding of the mechanisms controlling the establishment of such N2-fixing associations has been developed, using two maize inbred lines exhibiting different physiological characteristics. The bacterial-plant interaction has been characterized by means of a metabolomic approach. Two established model strains of Nif+ diazotrophic bacteria, Herbaspirillum seropedicae and Azospirillum brasilense and their Nif- couterparts defficient in nitrogenase activity, were used to evaluate the impact of the bacterial inoculation and of N2 fixation on the root and leaf metabolic profiles. The two N2-fixing bacteria have been used to inoculate two genetically distant maize lines (FV252 and FV2), already characterized for their contrasting physiological properties. Using a well-controlled gnotobiotic experimental system that allows inoculation of maize plants with the two diazotrophs in a N-free medium, we demonstrated that both maize lines were efficiently colonized by the two bacterial species. We also showed that in the early stages of plant development, both bacterial strains were able to reduce acetylene, suggesting that they contain functional nitrogenase activity and are able to efficiently fix atmospheric N2 (Fix+). The metabolomic approach allowed the identification of metabolites in the two maize lines that were representative of the N2 fixing plant-bacterial interaction, these included mannitol and to a lesser extend trehalose and isocitrate. Whilst other metabolites such as asparagine, although only exhibiting a small increase in maize roots following bacterial infection, were specific for the two Fix+ bacterial strains, in comparison to their Fix- counterparts. Moreover, a number
Wu, Liancheng; Li, Mingna; Tian, Lei; Wang, Shunxi; Wu, Liuji; Ku, Lixia; Zhang, Jun; Song, Xiaoheng; Liu, Haiping; Chen, Yanhui
In maize (Zea mays), leaf senescence acts as a nutrient recycling process involved in proteins, lipids, and nucleic acids degradation and transport to the developing sink. However, the molecular mechanisms of pre-maturation associated with pollination-prevention remain unclear in maize. To explore global gene expression changes during the onset and progression of senescence in maize, the inbred line 08LF, with severe early senescence caused by pollination prevention, was selected. Phenotypic observation showed that the onset of leaf senescence of 08LF plants occurred approximately 14 days after silking (DAS) by pollination prevention. Transcriptional profiling analysis of the leaf at six developmental stages during induced senescence revealed that a total of 5,432 differentially expressed genes (DEGs) were identified, including 2314 up-regulated genes and 1925 down-regulated genes. Functional annotation showed that the up-regulated genes were mainly enriched in multi-organism process and nitrogen compound transport, whereas down-regulated genes were involved in photosynthesis. Expression patterns and pathway enrichment analyses of early-senescence related genes indicated that these DEGs are involved in complex regulatory networks, especially in the jasmonic acid pathway. In addition, transcription factors from several families were detected, particularly the CO-like, NAC, ERF, GRAS, WRKY and ZF-HD families, suggesting that these transcription factors might play important roles in driving leaf senescence in maize as a result of pollination-prevention.
Full Text Available MicroRNAs (miRNAs play an important role in plant growth, development, and response to environment. For identifying and comparing miRNAs and their targets in seed development between two maize inbred lines (i.e. PH6WC and PH4CV, two sRNAs and two degradome libraries were constructed. Through high-throughput sequencing and miRNA identification, 55 conserved and 24 novel unique miRNA sequences were identified in two sRNA libraries; moreover, through degradome sequencing and analysis, 137 target transcripts corresponding to 38 unique miRNA sequences were identified in two degradome libraries. Subsequently, 16 significantly differentially expressed miRNA sequences were verified by qRT-PCR, in which 9 verified sequences obviously target 30 transcripts mainly involved with regulation in flowering and development in embryo. Therefore, the results suggested that some miRNAs (e.g. miR156, miR171, miR396 and miR444 related reproductive development might differentially express in seed development between the PH6WC and PH4CV maize inbred lines in this present study.
Bánáti, Hajnalka; Darvas, Béla; Fehér-Tóth, Szilvia; Czéh, Árpád; Székács, András
Levels of mycotoxins produced by Fusarium species in genetically modified (GM) and near-isogenic maize, were determined using multi-analyte, microbead-based flow immunocytometry with fluorescence detection, for the parallel quantitative determination of fumonisin B1, deoxynivalenol, zearalenone, T-2, ochratoxin A, and aflatoxin B1. Maize varieties included the genetic events MON 810 and DAS-59122-7 , and their isogenic counterparts. Cobs were artificially infested by F. verticillioides and F. proliferatum conidia, and contained F. graminearum and F. sporotrichoides natural infestation. The production of fumonisin B1 and deoxynivalenol was substantially affected in GM maize lines: F. verticillioides , with the addition of F. graminearum and F. sporotrichoides , produced significantly lower levels of fumonisin B1 (~300 mg·kg -1 ) in DAS-59122-7 than in its isogenic line (~580 mg·kg -1 ), while F. proliferatum , in addition to F. graminearum and F. sporotrichoides , produced significantly higher levels of deoxynivalenol (~18 mg·kg -1 ) in MON 810 than in its isogenic line (~5 mg·kg -1 ). Fusarium verticillioides , with F. graminearum and F. sporotrichoides , produced lower amounts of deoxynivalenol and zearalenone than F. proliferatum , with F. graminearum and F. sporotrichoides . T-2 toxin production remained unchanged when considering the maize variety. The results demonstrate the utility of the Fungi-Plex™ quantitative flow immunocytometry method, applied for the high throughput parallel determination of the target mycotoxins.
Melchinger, A E; Boppenmaier, J; Dhillon, B S; Pollmer, W G; Herrmann, R G
Restriction fragment length polymorphisms (RFLPs) have been proposed for the prediction of the yield potential of hybrids and the assignment of inbreds to heterotic groups. Such use was investigated in 66 diallel crosses among 6 flint and 6 dent inbreds from European maize (Zea mays L.) germ plasm. Inbreds and hybrids were evaluated for seven forage traits in four environments in the Federal Republic of Germany. Midparent heterosis (MPH) and specific combining ability (SCA) were calculated. Genetic distances (GD) between lines were calculated from RFLP data of 194 clone-enzyme combinations. GDs were greater for flint x dent than for flint x flint and dent x dent line combinations. Cluster analysis based on GDs showed separate groupings of flint and dent lines and agreed with pedigree information, except for 1 inbred. GDs of all line combinations in the diallel were partitioned into general (GGD) and specific (SGD) genetic distances; GGD explained approximately 20% of the variation among GD values. For the 62 diallel crosses (excluding 4 crosses of highly related lines), correlations of GD with F1 performance, MPH, and SCA for dry matter yield (DMY) of stover, ear, and forage were positive but mostly of moderate size (0.09≤r≤0.60) compared with the higher correlations (0.39≤r≤0.77) of SGD with these traits. When separate calculations were performed for various subsets, correlations of GD and SGD with DMY traits were generally small (r<0.47) for the 36 flint x dent crosses, significantly positive (r<0.53) for the 14 flint x flint crosses, and inconclusive for the 12 dent x dent crosses because of the lack of significant genotypic variation. Results indicated that RFLPs can be used for assigning inbreds to heterotic groups. RFLP-based genetic distance measures seem to be useful for predicting forage yield of (1) crosses between lines from the same germ plasm group or (2) crosses including line combinations from the same as well as different heterotic groups
Ettle, T; Lebzien, P; Flachowsky, G; Schwarz, F J
In this study we investigated the influence of harvest date and genotype on the ruminal degradability of the organic matter of ensiled maize grains. Grains of the varieties Avenir, Byzance, CGS 5104 and CGS 5107 from six different harvest dates were available; they are classified as intermediate types between flint and dent corn. The six harvest dates, during which time the dry matter content of the ensiled grains rose from 52% to 66%, extended from 1st September to 19th October. Assuming a passage rate of k = 0.08, the effective ruminal degradability declined in this period on average from 93% to just under 79%; variety-specific deviations also increased markedly during this period. The dry matter content (x, DM in %) of the ensiled grains had a profound influence on ruminal degradation: a highly significant curvilinear decline in ruminal degradability (y) was calculated at increasing DM levels (k = 0.08), which can be described by the equation y = -0.072x2 (+/- 0.010) + 7.417x (+/- 1.186) - 98.71 (+/- 34.58) (B = 0.96; sy.x[%] = 1.36). The ruminal degradability of ensiled maize grains is about 5-10% higher than that of fresh maize grains.
Li Qi; Shi Haichun; Ke Yongpei; Yuan Jichao; Yu Xuejie
Analyzing the biological effects and the genetic variations of maize mutagenic progenies is important to facilitate effective selections and utilization of the mutants. In this study, the genetic variation of 103 mutagenic progenies of M 3 lines of inbred lines 48-2 and R08 with 60 Co γ-rays inducement were evaluated with SSR molecular markers. The results indicated that, the amplitude of polymorphism information content (PIC) of the 48-2 and R08 M 3 lines ranged 0.307 ∼ 0.948 and 0.108 ∼ 0.955, with an average of 0.762 and 0.701, respectively. The amplitude of genetic diversity indexes (H') ranged 0.552 ∼ 2.830 and 0.254 ∼ 3.309, with an average of 1.830 and 1.777, respectively. The average value of genetic similarity coefficient of the 49 M 3 lines of 48-2 with its check (M673) was 0.8194. However, the average value of genetic similarity coefficient of the M 3 lines of R08 with its check (M487) was 0.8373. Based on the genetic similarity coefficient, inbred lines 48-2, R08 and their 101 M 3 lines were clustered in 7 and 5 populations respectively. This phenomenon indicated that massive genetic variation could appear in progenies due to irradiation. The strengthen of selection and utilization of mutants based on the breeding objectives and in accordance with the feature and regularity on genetic variations of main characteristics of mutant lines in various populations could be enhanced in breeding program, to some extent, which can increase the breeding efficiency of irradiation induced mutation in maize. (authors)
Odongo, O.M.; Abayo, G.
In the study seven maize varieties, Rachar, Nyamula, KK Pop24, KSTP94, H662, H511 and H512, were compared for their reactions towards striga infestation for two seasons (1995 and 1996 long rains) at four locations. The trial was conducted in a randomised complete block design with four replications. Data were taken on striga count, ear height, striga effect and grain yield. The striga count for six of the varieties did not differ significantly at except for H512 which supported significantly higher sriga plants an indication of H512 being more striga stimulant producer and parasiterised than the rest of the varieties.T-test showed that the variety Nyamula had the least yield reduction caused by striga among the tested varieties. across location means for the two seasons suggested that the varieties Nyamula and KSTP94 are more tolerant to striga attack than the other test varieties and could be recommended commercial hybrids H622 (3269 kg ha -1 ) and H512 (3758 kg ha -1 ) under striga-free conditions. KSTP94 was developed for striga tolerance and Nyamula is a landrace in striga infested areas. This explains why the two are superior to the rest under striga infestation
Ducruet, Jean-Marc; Roman, Miruna; Havaux, Michel; Janda, Tibor; Gallais, André
Maize (Zea mays L.) inbred lines of contrasting chilling sensitivity (three tolerant, three sensitive lines) were acclimated to 280 mumol photons m(-2) s(-1) white light at a 17 degrees C sub-optimal temperature. They showed no symptoms of photoinhibition, despite slight changes in photosystem II (PSII) fluorescence and thermoluminescence properties in two tolerant lines. A luminescence "afterglow" emission [Bertsch and Azzi (1965) Biochim Biophys Acta 94:15-26], inducible by a far-red (FR) illumination of unfrozen leaf discs, was detected either as a bounce in decay kinetics at constant temperatures or as a sharp thermoluminescence afterglow band at about 45 degrees C, in dark-adapted leaves. This band reflects the induction by warming of an electron pathway from stromal reductants to plastoquinones and to the Q(B) secondary acceptor of PSII, resulting in a luminescence-emitting charge recombination in the fraction of centres that were initially in the S(2/3)Q(B) non-luminescent state. A 5-h exposure of plants to growth chamber light shifted this luminescence emission towards shorter times and lower temperatures for several hours in the three chilling-tolerant lines. This downshift was not observed, or only transiently, in the three sensitive lines. In darkness, the downshifted afterglow band relaxed within hours to resume its dark-adapted location, similar for all maize lines. A faster dark re-reduction of P700(+) oxidized by FR light (monitored by 820-nm absorbance) and an increase of photochemical energy storage under FR excitation (determined by photoacoustic spectroscopy) confirmed that a cyclic pathway induced by white actinic light remained activated for several hours in the tolerant maize lines.
Gayral, Mathieu; Elmorjani, Khalil; Dalgalarrondo, Michèle; Balzergue, Sandrine M; Pateyron, Stéphanie; Morel, Marie-Hélène; Brunet, Sylvie; Linossier, Laurent; Delluc, Caroline; Bakan, Bénédicte; Marion, Didier
Major nutritional and agronomical issues relating to maize ( Zea mays ) grains depend on the vitreousness/hardness of its endosperm. To identify the corresponding molecular and cellular mechanisms, most studies have been conducted on opaque/floury mutants, and recently on Quality Protein Maize, a reversion of an opaque2 mutation by modifier genes. These mutant lines are far from conventional maize crops. Therefore, a dent and a flint inbred line were chosen for analysis of the transcriptome, amino acid, and sugar metabolites of developing central and peripheral endosperm that is, the forthcoming floury and vitreous regions of mature seeds, respectively. The results suggested that the formation of endosperm vitreousness is clearly associated with significant differences in the responses of the endosperm to hypoxia and endoplasmic reticulum stress. This occurs through a coordinated regulation of energy metabolism and storage protein (i.e., zein) biosynthesis during the grain-filling period. Indeed, genes involved in the glycolysis and tricarboxylic acid cycle are up-regulated in the periphery, while genes involved in alanine, sorbitol, and fermentative metabolisms are up-regulated in the endosperm center. This spatial metabolic regulation allows the production of ATP needed for the significant zein synthesis that occurs at the endosperm periphery; this finding agrees with the zein-decreasing gradient previously observed from the sub-aleurone layer to the endosperm center. The massive synthesis of proteins transiting through endoplasmic reticulum elicits the unfolded protein responses, as indicated by the splicing of bZip60 transcription factor. This splicing is relatively higher at the center of the endosperm than at its periphery. The biological responses associated with this developmental stress, which control the starch/protein balance, leading ultimately to the formation of the vitreous and floury regions of mature endosperm, are discussed.
Houndonougbo, Mankpondji Frederic; Chwalibog, Andrzej; Chrysostome, C.A.A.M.
-ecological zones and two varieties of white maize grains (Local and DMR-ESRW) produced in the same environmental conditions were compared. These grains were used in four balanced diets for unsexed broiler chickens (Re Bro) from 8 to 49 days of age. Per kg of dry matter (DM), a difference of about 0.396 MJ...... effect (P>0.05) of the grains' origin or variety on the growth performance of chickens. The daily feed intake, the daily weight gain, the feed conversion ratio and the final body weight of chickens at 28 and 49 days of age were similar between diets. In addition, the partial substitution of maize...... by soybean grains to supply mainly the dietary energy did not show an adverse effect of the diet on these variables. However, the variety of maize affected significantly the feed cost and the economic feed efficiency at starter phase. It can be concluded that under the particular conditions...
Akinyemi, Ayodele Jacob; Faboya, Oluwabamise Lekan; Olayide, Israel; Faboya, Opeyemi Ayodeji; Ijabadeniyi, Tosin
Cadmium (Cd) is one of the most toxic heavy metals that inhibit physiological processes of plants. Hence, the present study sought to investigate the effect of cadmium-contaminated seeds from two varieties of maize (Zea mays) on non-enzymatic antioxidant and nitric oxide levels. Seeds of yellow and white maize were exposed to different concentrations of Cd (0, 1, 3 and 5 ppm) for two weeks. The results from this study revealed that both varieties of maize bio-accumulate Cd in leaves in a dose-dependent manner. In addition, Cd exposure caused a significant (p < 0.05) decrease in total phenolic, GSH and nitric oxide (NO) levels at the highest concentration tested when compared with control. Therefore, the observed decrease in NO and endogenous antioxidant status by Cd treatment in maize plants could suggest some possible mechanism of action for Cd-induced oxidative stress and counteracting effect of the plants against Cd toxicity.
Endophytes are microorganisms that live within plant tissues without causing symptoms of disease. The objective of this investigation was to isolation and identification of fungal endophytes from roots of maize plant var. Pulut (a local variety of south Sulawesi). Sixty three isolates of fungal endophytes were isolated from the root of maize var. Pulut. The isolates belonged to six genera, namely :Trichoderma sp., Fusarium sp., Acremonium sp., Aspergillus sp., Penicillium sp., and Botryodiplo...
Full Text Available report world maize production for 2007/2008 was 791.6 million tons (USDA, 2009). Genetic engineering of agricultural crops has played an important role in crop improvement where it has been used to increase resistance to disease and stresses... crops. Both the added value and the current challenges are discussed. RESULTS In this study we evaluated the effects of genotype and environmental conditions on maize kernels at the transcriptome, proteome and metabolome levels. To this effect...
Full Text Available Abstract Background Cell-wall digestibility is the major target for improving the feeding value of forage maize. An understanding of the molecular basis for cell-wall digestibility is crucial towards breeding of highly digestible maize. Results 865 candidate ESTs for cell-wall digestibility were selected according to the analysis of expression profiles in 1 three sets of brown-midrib isogenic lines in the genetic background of inbreds 1332 (1332 and 1332 bm3, 5361 (5361 and 5361 bm3, and F2 (F2, F2 bm1, F2 bm2, and F2 bm3, 2 the contrasting extreme lines of FD (Flint × Dent, AS08 × AS 06, DD1 (Dent × Dent, AS11 × AS09, and DD2 (Dent × Dent, AS29 × AS30 mapping populations, and 3 two contrasting isogenic inbreds, AS20 and AS21. Out of those, 439 ESTs were assembled on our "Forage Quality Array", a small microarray specific for cell wall digestibility related experiments. Transcript profiles of 40 lines of a Flint × Flint population were monitored using the Forage Quality Array, which were contrasting for cell wall digestibility. Using t-tests (p Conclusion 102 candidate genes for cell-wall digestibility were validated by genetical genomics approach. Although the cDNA array highlights gene types (the tested gene and any close family members, trans-acting factors or metabolic bottlenecks seem to play the major role in controlling heritable variation of gene expression related to cell-wall digestibility, since no in silico mapped ESTs were in the same location as their own eQTL. Transcriptional variation was generally found to be oligogenic rather than monogenic inherited due to only 26% ESTs detected a single eQTL in the present study. One eQTL hotspot was co-localized with cell wall digestibility related QTL cluster on bins 3.05, implying that in this case the gene(s underlying QTL and eQTL are identical. As the field of genetical genomics develops, it is expected to significantly improve our knowledge about complex traits, such as cell
Gbadebo Lawrence Olaoye
Full Text Available Efficiency of soil water utilization under moisture deficit condition can help reduce the adverse effects of drought stress in crops. Growth, physiological responses and grain yield loss due to moisture deficits around flowering, were investigated in maize populations derived by reciprocal crosses between two adapted maize cultivars (DMR-LSR-Y and AFO and two drought tolerant (DT inbred lines (DT-S3-Y and DT-S3-W under glass house conditions. The crosses and their parents and crosses were subjected to irrigation treatments equivalent to 25, 50, 75 and 100% field capacity (FC as well as water withdrawal for two weeks at vegetative, pre and post-anthesis stages respectively. Â Reduction in biomass yield (BMY under low moisture regimes were within the range of 75 to 61% of BMY obtained under favourable irrigation treatments while Pre and post- anthesis moisture deficits also significantly reduced grain yield by 49 and 66% of well-watered condition. Reciprocal crosses between AFO and DT-S3-Y consistently gave highest BMY under irrigation treatment equivalent to 75% FC and above with % gains ranging from 3.05 to 44.2 respectively. All crosses except two of them (DT-S3-Y x AFO and AFO x DT-S3-W evidenced superiority for BMY and water use efficiency (WUE over their respective better parents, under low moisture conditions. Heterotic response for grain yield differed among crosses depending on soil moisture condition. There was no direct association between drought sensitivity index (DSI and grain yield in the populations but genotypes with short anthesis-silking-interval (ASI under moisture deficit conditions showed superiority for grain yield over those with longer ASI. The above results suggest that short ASI when combined with high grain yield under moisture deficit conditions is a better selection tool for identifying drought tolerant genotypes than DSI.
Maize is the principle food staple in Zambia, providing both food and income for most of the rural populace. It is estimated that over 50% of the daily caloric intake is derived from maize; with an average consumption of over 85kg per year. Because of the importance of maize, a number of improved
Akmal, M.; Hameed-urRehman; Farhatullah; Asim, M.; Akbar, H.
An experiment was conducted at NWFP Agricultural University, Peshawar, to study maize varieties and Nitrogen (N) rates for growth, yield and yield components. Three varieties (Azam, Jalal and Sarhad white) and three N rates (90, 120, 150, kg N ha/sup -1/) were compared. Experiment was conducted in a Randomized Complete Block design; split plot arrangement with 4 replications. Uniform and recommended cultural practices were applied during the crop growth. The results revealed that maize variety 'Jalal' performed relatively better crop growth rate (CGR) and leaf area profile (LAP) at nodal position one to six as compared to the other two varieties (Sarhad white and Azam). This resulted higher radiation use efficiency by the crop canopy at vegetative stage of development and hence contributed higher assimilates towards biomass production. Heavier grains in number and weight were due to higher LAP and taller plants of Jalal which yielded higher in the climate. Nitrogen applications have shown that maize seed yield increase in quadratic fashion with increased N to a plateau level. Considering soil fertility status and cropping system, the 150 kg ha/sup -1/ N application to maize variety Jalal in Peshawar is required for maximum biological and seed production. (author)
Full Text Available Salinity is a major abiotic stress that limits plant productivity and quality throughout the world. Roots are the sites of salt uptake. To better understand salt stress responses in maize, we performed a comparative proteomic analysis of seedling roots from the salt-tolerant genotype F63 and the salt-sensitive genotype F35 under 160 mM NaCl treatment for 2 days. Under salinity conditions, the shoot fresh weight and relative water content were significantly higher in F63 than in F35, while the osmotic potential was significantly lower and the reduction of the K+/Na+ ratio was significantly less pronounced in F63 than in F35. Using an iTRAQ approach, twenty-eight proteins showed more than 2.0- fold changes in abundance and were regarded as salt-responsive proteins. Among them, twenty-two were specifically regulated in F63 but remained constant in F35. These proteins were mainly involved in signal processing, water conservation, protein synthesis and biotic cross-tolerance, and could be the major contributors to the tolerant genotype of F63. Functional analysis of a salt-responsive protein was performed in yeast as a case study to confirm the salt-related functions of detected proteins. Taken together, the results of this study may be helpful for further elucidating salt tolerance mechanisms in maize.
Marilia Rodrigues de Silva
Full Text Available ABSTRACT: The asexually gene introduction by genetic engineering has brought enormous possibilities to innovate plant breeding. However, principally because of the low in vitro response, genetic transformation has been restricted to only certain genotypes of agronomically significant species. With the objective of establishing a protocol for genetically transforming the Brazilian BR 451 maize variety through Agrobacterium tumefaciens, it was studied the capacity of plant regeneration in vitro from embryogenic calli cultivated in three regeneration media, each having different growth regulators. It was also evaluated the temperature stress effect on the transformation of the immature embryos with A. tumefaciens EHA 101 containing the plasmid pTF102 with uidA and bar genes. The BR 451 variety embryos and those of the Hi-II hybrid (control were exposed to three treatments applied as they were being infected with the agrobacteria (a infection at 25°C; (b infection at 40°C; (c pretreatment at 40°C for 5 seconds followed by infection at 25°C. Transformation was determined by uidA gene expression and through the callus resistant to the herbicide Bialaphos® formation. Embryos infected at 40°C showed a higher degree of genetic transformation in the Hi-II, although the same was not noted in BR 451. When growth regulators were added to the culture medium the number of regenerated BR 451 plants showed no increase.
Bakht, J.; Rehman, H.; Shafi, M.; Uddin, R.
Field experiment was conducted at KPK Agricultural University, Peshawar, Pakistan to find out the effect of planting methods on the yield and yield components of maize varieties. Analysis of the data revealed that planting methods had a significant effect on days to tasseling, days to silking, plant height, number of plants ha/sup -1/ at harvest, thousand grain weight, grain yield, biological yield, fresh weed biomass m/sup -2/ and non-significant effect on days to emergence, emergence m-2, number of cobs plant/sup -1/, grains ear/sup -1/, harvest index and dry weed biomass m/sup -2/. Similarly, the effect of varieties was also significant on all parameters except fresh and dry weed biomass m/sup -2/. Maximum emergence m/sup -2/, days to tasseling, days to silking, plant height, number of plants ha/sup -1/at harvest, grains ear/sup -1/, thousand grain weight, grain yield and biological yield were recorded in ridge planting method. Similarly, Jalal sown on ridges took maximum days to emergence, emergence m/sup -2/, plant height, number of cobs plant /sup -1/, grains ear/sup -1/, thousand grain weight, grain yield, biological yield, fresh weed biomass and dry weed biomass. (author)
Frimpong, J. O.
The production of rain-fed maize in the Kwabenya-Atomic area of the coastal savannah environment of Ghana is limited by low and erratic rainfall. Enhancing maize production in the area will require the use of maize varieties efficient in the use of soil moisture. The study was, therefore, conducted to evaluate three recently released maize varieties (Obatanpa, Mamaba, and Golden Crystal) for their efficiency in the use of soil moisture for total dry matter and grain production and consequently identify the maize varieties suitable for rain-fed production in the Kwabenya-Atomic area. Field experiments were conducted m 2008 during the major and minor cropping seasons at Kwabenya-Atomic area in Ghana using three maize varieties grown at a planting distance of 0.4 m within rows and 0.8 m between rows. The experimental design used was the randomised complete block design in four replicates. Plants were sampled every two weeks throughout the maize growing seasons. Access tubes installed in each sub-plot facilitated simultaneous moisture monitoring with the aid of a neutron probe (CPN (R) 503 Hydroprobe) in a 120 cm soil profile. The moisture content values were used for the estimation of actual evapotranspiration of the maize crop using the water balance approach. Grain yield (GY) and its associated water use efficiency (WUE GY ) were significantly different (P ≤ 0.05) among the maize varieties during the major cropping season with Mamaba producing the highest grain yield of 7250.0 kg ha -1 and WUE GY of 13.2 kg ha -1 mm -1 . For the minor cropping season, no significant difference was observed in grain yield, which ranged between 5800.0 and 7200.0 kg ha -1 , with Obatanpa producing the highest grain yield. No significant difference was observed in WUE GY during the minor cropping season which ranged between 14.6 and 19.1 kg ha -1 mm -1 with Obatanpa having the highest WUE GY . The maize genotype produced similar total dry matter (TDM) during each of the cropping
Zhang, Zi-Long; Hou, Jun-Ling; Wang, Wen-Quan; Zhang, Zhi-Xin; Zhang, Shi-Xiu
It has been showed that there were obvious obstacle effects of Panax notoginseng replanting. Crop rotation was the main effective technique to overcome the obstacle. To find a reasonable crop rotation system for P. notoginseng, aqueous extracts from root, stem and leaf of P. notoginseng were analyzed for allelopathic effect on three maize varieties (which are often grown in regions where P. notoginseng grown). The main results were as follows: (1) Allelopathic effect of P. notoginseng stem and leaf extracts on the three other tested plants was stronger than that of root extracts; (2) Corn was more vulnerable to the effects of allelochemicals at seedling stage than at germination stage, and the corn root was more sensitive than aerial part to allelochemicals; (3) Lusan No. 3 and Yunrui No. 1 showed resistance to P. notoginseng allelopathy, with respective comprehensive sensitivity indexes (M3) of - 0.089 3 and -0.159 2, while Bainuo No. 1 is sensitive at M3 = -0.261 0. It then can be concluded that Lusan No. 3 and Yunrui No. 1 may be an alternative rotation plants for overcoming P. notoginseng continuous cropping obstacle.
Maize is the primary staple crop in Kenya and plays an important role in the livelihood of the people of Kenya. Its availability and abundance determines the level of welfare and food security in the country. In Kenya, future increases in maize production to meet domestic demand will have to rely on improvements in yield per ...
Apr 2, 2013 ... Figure 3: Analysis of Strengths, Weaknesses, Opportunities and Threats. (SWOT analysis)*. *Template modified . CONCLUSION. Maize is a monoecious, protandrous plant. Protandry and wind pollination makes maize suitable for maximum cross-pollination. To produce hybrid seed, reception of.
Melchinger, A E; Geiger, H H; Schnell, F W
Three flint and three dent maize (Zea mays L.) inbred lines, their possible F1 crosses, F2 and backcross progenies, and all possible three-way crosses were evaluated in a three-year experiment for yield, ear moisture, and plant height. The purpose was to estimate genetic parameters in European breeding materials from (i) generation means analysis, (ii) diallel analysis of generation means, and (iii) analysis of F1 and three-way cross hybrids. Method (i) was based on the F∞-metric model and methods (ii) and (iii) on the Eberhart-Gardner (1966) genetic model; both models extended for heterotic maternal effects.Differences among generation means for yield and plant height were mainly attributable to dominance effects. Epistatic effects were significantly different from zero in a few crosses and considerably reduced heterosis in both traits. Additive x additive and domiance x dominance effects for yield were consistently positive and negative, respectively. Significant maternal effects were established to the advantage of generations with a heterozygous seed parent. In the diallel analysis, mean squares for dominance effects were greater than for additive effects for yield and plant height but smaller for ear moisture. Though significant for yield and plant height, epistatic variation was small compared to additive and dominance variation. Estimates of additive x additive epistasis for yield were significantly negative in 11 of 15 crosses, suggesting that advantageous gene combinations in the lines had been disrupted by recombination in the segregating generations. The analysis of hybrids supported the above findings regarding the analysis of variance. However, the estimates of additive x additive epistasis for yield were considerably smaller and only minimally correlated with those from the diallel analysis. Use of noninbred materials as opposed to materials with different levels of inbreeding is considered the main reason for the discrepancies in the results.
Full Text Available Avaliaram-se 440 linhagens endogâmicas de milho do Instituto Agronômico de Campinas, obtidas a partir de diversas populações, quanto à severidade da ferrugem tropical, causada por Physopella zeae, em condições naturais de infecção. Foram instalados 22 experimentos em blocos ao acaso com duas repetições, em 1993/94, em Ribeirão Preto (SP e utilizados como testemunhas resistente e suscetível os híbridos Z 8568 e P 3069 respectivamente, incluídos de forma intercalar. A avaliação foi realizada aos 30 dias após o florescimento, mediante uma escala de notas de 1 a 9, correspondendo a 0%; 1%; 2,5%; 5%; 10%; 25%; 50%; 75% e >75% de área foliar afetada. Todas as populações estudadas apresentaram variabilidade quanto à resistência a P. zeae, indicando que a utilização de métodos de seleção recorrente pode ser eficaz no melhoramento de populações visando à resistência ao patógeno.Four hundred and forty maize inbred lines, developed at Instituto Agronômico de Campinas, State of São Paulo, Brazil, derived from several populations, were evaluated, in field conditions, as to tropical rust resistance caused by Physopella zeae. Twenty two experiments were carried out in randomized complete block designs, with two replications each, during 93/94 summer season, in Ribeirão Preto, State of Sao Paulo, Brazil. Resistant (Z 8568 and susceptible (P 3069 hybrids were used as controls. The evaluations were performed 30 days after flowering, according to a scale of notes from 1 to 9 (0%; 1%; 2.5%; 5%; 10%; 25%; 50%; 75% and >75% affected leaf area. All populations showed variability as to P. zeae reaction, suggesting that recurrent selection might be effective to achieve tropical rust resistance.
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.
Iversen, Marianne; Grønsberg, Idun M; van den Berg, Johnnie; Fischer, Klara; Aheto, Denis Worlanyo; Bøhn, Thomas
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.
This highactivity was correlated with high speciicity of corn lipase on linoleic acid. Thermal inactivation studies showed that the enzyme was stable up to 50oC and showed rapid inactivation above this temperature. Its optimum temperature was 50oC and the optimum pH, 8. Keywords: Lipase, Enzymes, Maize, Thermal ...
Evaluation of genetic distances between maize inbred lines can be used to maximise heterosis in hybrids. This study was conducted to determine genetic distances among 25 maize inbred lines in the Maize streak virus disease (MSVD) QTL region to develop MSVD-resistant hybrids. The inbred lines were genotyped using ...
Full Text Available To investigate unintended effects in genetically modified crops (GMCs, a comparative proteomics analysis between the leaves of the phytase-transgenic maize and those of non-transgenic plants was performed by using two-dimensional gel electrophoresis and mass spectrometry. A total of 57 differentially expressed protein spots (DEPs were successfully identified, which represented 44 unique proteins. Functional classification of the identified unique proteins showed that these proteins were predominantly involved in carbohydrate transport and metabolism, followed by post-translational modification. KEGG pathway analysis revealed that most of the DEPs participated in carbon fixation in photosynthesis. Comparison of the changes in the protein and gene transcript levels of the identified unique proteins showed that most proteins had a similar pattern of changes between proteins and transcripts. Our results suggested that although some significant differences were observed, the proteomic patterns were not substantially altered between the leaves of phytase-transgenic maize and its non-transgenic isogenic type. Moreover, none of the DEPs was identified as a new toxic protein or an allergenic protein. The differences of proteome between the two kinds of maize leaves might be attributed to both genetic modification and hybrid influence.
Hurtado, E.; Labrada, A.
Height under laboratory conditions and survival under field conditions have been the classical criteria to determine radiosensitivity in different cultivations. There are criteria referring that when productivity indexes are measured and expressed as control percentage, this would allow to make a radiosensitivity curve and to obtain dose-50. Our purpose was to obtain this relationships from the productivity indexes in a first-generation from the maize plants irradiated. It can be said that yield components, the ear's weight and the ear's fertility were the most radiosensible
Tan, Yanhua; Yi, Xiaoping; Wang, Limin; Peng, Cunzhi; Sun, Yong; Wang, Dan; Zhang, Jiaming; Guo, Anping; Wang, Xuchu
To investigate unintended effects in genetically modified crops (GMCs), a comparative proteomic analysis between the leaves of the phytase-transgenic maize and the non-transgenic plants was performed using two-dimensional gel electrophoresis and mass spectrometry. A total of 57 differentially expressed proteins (DEPs) were successfully identified, which represents 44 unique proteins. Functional classification of the identified proteins showed that these DEPs were predominantly involved in carbohydrate transport and metabolism category, followed by post-translational modification. KEGG pathway analysis revealed that most of the DEPs participated in carbon fixation in photosynthesis. Among them, 15 proteins were found to show protein-protein interactions with each other, and these proteins were mainly participated in glycolysis and carbon fixation. Comparison of the changes in the protein and tanscript levels of the identified proteins showed that most proteins had a similar pattern of changes between proteins and transcripts. Our results suggested that although some significant differences were observed, the proteomic patterns were not substantially different between the leaves of the phytase-transgenic maize and the non-transgenic isogenic type. Moreover, none of the DEPs was identified as a new toxic protein or an allergenic protein. The differences between the leaf proteome might be attributed to both genetic modification and hybrid influence.
Capocchi, Antonella; Bottega, Stefania; Spanò, Carmelina; Fontanini, Debora
Flours of four pigmented (from orange to red and dark red) local Italian corns, studied for their soluble, soluble conjugate, and insoluble-bound phenols and flavonoids, showed a prevalence of the insoluble-bound fraction (70-80%). Correlations were found between the flours antioxidant capacity, measured with CUPRAC, FRAP, and DPPH methods, and soluble phenols and flavonoids content. A correlation was also found between ascorbic acid content and flours antioxidant power. Anthocyanins were present in small amounts in the red/dark red seeds; however, acid-alcohol assays and spectral analyses of pericarp extracts indicated the presence of red-brick phlobaphenes in these varieties. Spectrophotometrically quantified total carotenoids were significantly higher in one of the local varieties (Nano); RP-HPLC analyses indicated that the local varieties contained significantly higher amounts of zeaxanthin and β-carotene, and lower amounts of lutein, than a commercial line. Among local varieties, Nano expressed the highest levels of zeaxanthin, β-carotene, and β-cryptoxanthin.
Pajić Zorica; Radosavljević Milica; Filipović Milomir; Todorović Goran; Srdić Jelena; Pavlov Milovan
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...
Exposure to elevated tropospheric ozone concentration ([O3]) accelerates leaf senescence in many C3 crops. However, the effects of elevated [O3] on C4 crops including maize (Zea mays L.) are poorly understood in terms of physiological mechanism and genetic variation in sensitivity. Using Free Air ga...
Ridine, W.; Ngakou, A.; Mbaiguinam, M.; Namba, F.; Anna, P
The present experiment was conducted in Pala, region of the Mayo-Kebi West division, in a contribution to improve maize production in Chad. The work was oriented towards the evaluation of the interactions between chemical (NPK) and organic (bat's manure) fertilizers on growth and yield attributes of TZEE-W and IB selected maize varieties. The experimental design was a (5x2)x4 factorial design in which the main factor was the proportion of organic/chemical fertilizer (%), and the maize variety as the secondary factor, comprising the following six treatments repeated four times: control (T0) with 0 % NPK and 0 % bat's manure; T1 with 100% NPK; T2 with 100% bat's manure; T3 with 75% NPK and 25% bat's manure; T4 with 75% bat's manure and 25% NPK; T5 with 50% bat's manure and 50% NPK. Results show a variation in experimental soils pH of treatments from 5.91 to 7.92, depending on the proportion of the fertilizers applied. There were significant yield differences among treatments, as well as maize varieties. The 50% NPK+50% bat's manure was found as the best treatment to significantly (p<0.0001) enhance the yield of IB (51.2 t/ha) and TZEE-W (37.9 t/ha) maize varieties compared to their respective controls (7.25 t/ha and 6.76 t/ha). These results suggest that the combination at equal proportion of NPK and bat's manure could be recommended to sustainably improve maize production in Pala-Chad, thus with a considerable alleviation of the pollution risks that have been attributed to chemical fertilizer. (author)
Revilla Temiño, Pedro; Abuín, María del Carmen; Malvar Pintos, Rosa Ana; Soengas Fernández, María del Pilar; Ordás López, Bernardo; Ordás Pérez, Amando
Conservation of maize inbred lines in different stations causes variability among strains. The objective of this research was to determine agronomic and molecular differences in American sweet corn inbreds maintained in Spain. American and Spanish strains of five sweet corn inbred lines were characterized by using 34 RAPD primers that produced 168 consistent bands. Strains of four of these inbreds were crossed in a diallel design, and hybrids were evaluated in four environments in northwester...
Xuan, Ning; Zhao, Chuanzhi; Peng, Zhenying; Chen, Gao; Bian, Fei; Lian, Mingzheng; Liu, Guoxia; Wang, Xingjun; Bi, Yuping
Maize is one of the most important food crops. Rice black-streaked dwarf virus is a maize rough dwarf disease pathogen. The occurrence and transmission of maize rough dwarf disease brings great damage to maize production. The technology of using artificial miRNA to build antiviral plant has been proven effective in a variety of plants. However, such trials in maize have not been reported. We designed primers based on the sequence of maize zea-miR159a precursor and sequence of function protein genes and silencing RBSDV coding genes in RBSDV genome. We constructed amiRNA (artificial miRNA) gene for silencing RBSDV coding gene and gene silencing suppressor. We constructed pCAMBIA3301-121-amiRNA plant expression vector for transforming maize inbred lines Z31 by using agrobacterium mediated method. After molecular analysis of transgenic maize, homozygous lines with high miRNA expression were selected by molecular detection for a subsequent natural infection experiment. We studied the severity of maize rough dwarf disease according to a grading standard (grade 0 to 4). The experiment results showed that the disease resistance of transgenic homozygous maize with the anti-rough dwarf virus amiRNA vector was better than that of wild type. Among the transgenic maize, S6-miR159 transgenic maize had high disease resistance. It is feasible to create new maize variety by the use of artificial miRNA.
Li, Yunhe; Meissle, Michael; Romeis, Jörg
We investigated the use of maize pollen as food by adult Chrysoperla carnea under laboratory and field conditions. Exposure of the insects to insecticidal Cry proteins from Bacillus thuringiensis (Bt) contained in pollen of transgenic maize was also assessed. Female C. carnea were most abundant in a maize field when the majority of plants were flowering and fresh pollen was abundant. Field-collected females contained an average of approximately 5000 maize pollen grains in their gut at the peak of pollen shedding. Comparable numbers were found in females fed ad libitum maize pollen in the laboratory. Maize pollen is readily used by C. carnea adults. When provided with a carbohydrate source, it allowed the insects to reach their full reproductive potential. Maize pollen was digested mainly in the insect's mid- and hindgut. When Bt maize pollen passed though the gut of C. carnea, 61% of Cry1Ab (event Bt176) and 79% of Cry3Bb1 (event MON 88017) was digested. The results demonstrate that maize pollen is a suitable food source for C. carnea. Even though the pollen grains are not fully digested, the insects are exposed to transgenic insecticidal proteins that are contained in the pollen. Copyright 2009 Elsevier Ltd. All rights reserved.
Full Text Available A utilização de híbridos simples comerciais de milho é uma das opções de populações para a extração de linhagens, porque são adaptados e provavelmente concentram alta freqüência de alelos favoráveis já fixados. Mesmo nos locos que estão segregando, a freqüência de alelos favoráveis é 0,5. Assim, a identificação de populações promissoras, derivadas de híbridos simples superiores, é uma boa estratégia para aumentar a eficiência dos programas de melhoramento. As populações derivadas dos híbridos simples comerciais AG9012 e C333 foram avaliadas com o objetivo de verificar o potencial dessas para extração de linhagens superiores, por meio das estimativas de parâmetros genéticos e fenotípicos, da estimativa de m+a e a metodologia proposta por Jinks & Pooni (1976. Foram avaliadas 169 famílias S1 de cada população, durante a safra agrícola de 1999/2000, na área experimental do Departamento de Biologia da UFLA, em Lavras - MG, em látice simples 13x13, sendo as parcelas constituídas por uma linha de 3 m. As características analisadas foram incidência de Phaeosphaeria maydis em duas épocas, altura de plantas, altura de espigas e produtividade de espigas despalhadas. Foi constatado que há possibilidade de se obterem linhagens com bom desempenho per se, sendo a população derivada do C333 a mais promissora, por associar resistência a Phaeosphaeria maydis e possuir média mais alta e maior probabilidade de obtenção de linhagens superiores. A metodologia proposta por Jinks & Pooni (1976 mostrou-se mais informativa do que a estimativa de m+a para a escolha de populações, mas, quando possível, as duas podem ser utilizadas simultaneamente para auxiliar na decisão dos melhoristas.Populations derived from commercial single hybrids are one of the breeder options for inbred line extraction because of their adaptation and probable high frequency of loci with fixed favorable alleles. Even the segregating loci carry
medium-maturity maize genotypes, provide information to clarify the relationship among them and identify suitable lines for distribution to growers. Six mid-altitude adapted maize inbred lines and six lowland adapted maize inbred lines were crossed in a full diallel mating system. The resulting 132 crosses, excluding the ...
Zeljenková, Dagmar; Aláčová, Radka; Ondrejková, Júlia; Ambrušová, Katarína; Bartušová, Mária; Kebis, Anton; Kovrižnych, Jevgenij; Rollerová, Eva; Szabová, Elena; Wimmerová, Soňa; Černák, Martin; Krivošíková, Zora; Kuricová, Miroslava; Líšková, Aurélia; Spustová, Viera; Tulinská, Jana; Levkut, Mikuláš; Révajová, Viera; Ševčíková, Zuzana; Schmidt, Kerstin; Schmidtke, Jörg; Schmidt, Paul; La Paz, Jose Luis; Corujo, Maria; Pla, Maria; Kleter, Gijs A; Kok, Esther J; Sharbati, Jutta; Bohmer, Marc; Bohmer, Nils; Einspanier, Ralf; Adel-Patient, Karine; Spök, Armin; Pöting, Annette; Kohl, Christian; Wilhelm, Ralf; Schiemann, Joachim; Steinberg, Pablo
The GRACE (GMO Risk Assessment and Communication of Evidence; www.grace-fp7.eu ) project was funded by the European Commission within the 7th Framework Programme. A key objective of GRACE was to conduct 90-day animal feeding trials, animal studies with an extended time frame as well as analytical, in vitro and in silico studies on genetically modified (GM) maize in order to comparatively evaluate their use in GM plant risk assessment. In the present study, the results of a 1-year feeding trial with a GM maize MON810 variety, its near-isogenic non-GM comparator and an additional conventional maize variety are presented. The feeding trials were performed by taking into account the guidance for such studies published by the EFSA Scientific Committee in 2011 and the OECD Test Guideline 452. The results obtained show that the MON810 maize at a level of up to 33 % in the diet did not induce adverse effects in male and female Wistar Han RCC rats after a chronic exposure.
Margarida Agostinho Lemos
Full Text Available Em 1996/97 foram avaliados em Pesqueira e Vitória de Santo Antão (PE, 45 híbridos simples superdoce obtidos de um cruzamento dialélico completo entre dez linhagens S4 e suas linhagens parentais. O delineamento utilizado foi látice 7 x 8 com duas repetições por local. Foram estimados os efeitos das capacidades geral (CGC e específica (CEC de combinação e os valores de heterose para peso de espiga com palha (PECP, peso de espiga sem palha (PESP e rendimento de espiga (REND = PESP/PECP x 100. Os efeitos de CGC e CEC foram significativos (PIn 1996/97, 45 single cross supersweet maize hybrids, from a complete diallel cross involving ten inbred lines (S4 and their parents, were evaluated at Pesqueira and Vitória de Santo Antão, Brazil. A látice 7 x 8 design was used with two replications for each location. The general (GCA and specific (SCA combining ability effects and heterosis value were estimated for husked ear weight (HEW, unhusked ear weight (UEW and ear rate (ER = UEW/HEW x 100. The general and specific combining ability effects were significant (P<0.01 for all characteristics. Inbreds L5 = 76.5%; L7 = 71.2% and L4 = 69.6% (Pesqueira; L4 = 70.8%; L5 = 69.4% and L7 = 65.3% (Vitória de Santo Antão showed the highest (ER, and the highest GCA effects at both locations. The best crosses for ER were: L4 x L8 = 74.9% (Pesqueira and L7 x L8 = 70.3% (Vitória de Santo Antão, with the highest SCA effects at both locations. For ER, heterosis values related to parental mean ranged from -20.19 to 24.01% (Pesqueira and -18.02 to 16.76% (Vitória de Santo Antão. Heterosis values related to the higher yielding parent ranged from -23.52 to 22.99% (Pesqueira and -22.05 to 12.03% (Vitória de Santo Antão.
Aurélio Mendes Aguiar
Full Text Available The utilization of diallel crosses for identification of superior combinations is a common practice in maize (Zea mays L. breeding programs. This methodology allows the estimation of the combining ability of genotypes being evaluated. In this work, five inbred lines were evaluated as to their general (GCA and specific (SCA combining abilities, by using a complete diallel scheme. The single-crosses produced between these inbred lines were evaluated in seven environments, along with two checks, by using a randomized complete block design. Traits analized were: grain yield, plant height, ear height, ear placement, and prolificacy. A diallel analysis was carried out, following an adaptation of Griffing's method IV, in addition to hybrid stability and adaptability analyses. Significant differences were detected for entries and environments for all traits. The interaction genotype vs. environment was significant for all traits. GCA's were significant for all traits, while SCA's were non-significant only for ear placement. For grain yield, both additive (GCA and non-additive (SCA effects were important, while for the remaining traits additive effects were more important. The high yielding single-cross was obtained from the cross of lines L-08-05F and L-38-05D. Those inbred lines showed higher GCA's and their cross also had high SCA; also, it is responsive to environment improvements and reasonably stable. The second in rank high yielding single-cross, L-46-10D x L-08-05F, showed wide adaptability and stability.No melhoramento de milho (Zea mays L., a utilização de cruzamentos dialélicos visando identificação de combinações superiores é uma prática comum. Esta metodologia visa estimar a capacidade de combinação dos materiais avaliados. Neste trabalho, cinco linhagens endogâmicas foram avaliadas quanto às capacidades gerais (CGC e específica (CEC de combinação, utilizando o esquema de dialelo completo. Os híbridos simples produzidos
Maria Elisa Ayres Guidetti Zagatto Paterniani
Full Text Available Avaliaram-se dez linhagens de milho do programa de melhoramento do Instituto Agronômico (IAC, em cruzamentos dialélicos e os 45 híbridos resultantes quanto à tolerância à toxicidade de alumínio em laboratório. Estimou-se a tolerância pelo comprimento líquido da radícula (CLR de plântulas em solução nutritiva contendo 4,5 mg.L-1 de alumínio, em ensaio sob delineamento experimental de blocos casualizados com quatro repetições, utilizando-se como padrões linhagens sensível e tolerante de IAC Taiúba. Apresentam-se, ainda, resultados da produtividade desses cruzamentos em ensaios de campo. Identificaram-se linhagens que constituem fontes de tolerância (L 06 e L 09 e híbridos tolerantes à toxicidade de alumínio com elevada produtividade em solos corrigidos. Na análise dialélica, o desdobramento dos efeitos de tratamentos, em capacidade geral (CGC e específica (CEC de combinação, indicou a predominância de efeitos aditivos na manifestação da tolerância ao alumínio tóxico. Obtiveram-se elevados valores de heterose, indicando a existência de interações não alélicas na manifestação do CLR. O híbrido HS 10X11 (denominado IAC 21 aliou alta produtividade e tolerância ao alumínio, apresentando a maior estimativa da CEC para CLR.Ten inbred lines and the resulting forty-five hybrids from the maize IAC breeding program were evaluated for Al tolerance by the nutrient solution technique. Net radicle lengths (CLR of plants grown with 4.5 mg.L-1 were used to estimate Al tolerance. The experimental design was randomized complete block with four replications, and it was used two divergent inbred lines IAC Taiuba as control for Al tolerance and sensitivity, respectively. In addition to these data, it is shown also the grain yield of the same materials from field plots. It was identified two inbred lines (L 06 and L 09 as Al tolerance sources and hybrids potentially adapted to acid soil conditions (tolerant to Al toxicity
MAX WENDEL PAULA LIMA
Full Text Available O sucesso de um programa de melhoramento de milho visando à obtenção de híbridos está intimamente ligado à identificação da população mais promissora para a extração de linhagens. O presente trabalho objetivou identificar procedimentos para a escolha dessas populações. Para isso, foram obtidas populações segregantes S0, S1 e 196 famílias S0:1 de cada um dos quatro materiais comerciais avaliados: híbridos simples (C 333B e Z 8392, duplo (AG 1051 e variedade (BR-105. Os experimentos foram conduzidos na safra agrícola 98/99 em duas localidades na região sul do Estado de Minas Gerais: Lavras e Ijaci. Na avaliação das 196 famílias S0:1 de cada população foi empregado o delineamento látice simples 14 x 14. Adicionalmente foi instalado um experimento em blocos casualizados, com 4 repetições, para avaliação simultânea das gerações F1, S0 e S1 A partir dos dados de produtividade de espigas despalhadas (kg por parcela das gerações F1, S0 e S1, foram obtidas as estimativas da contribuição dos locos em homozigose (m + a e em heterozigose (d. Foram também foram estimados os parâmetros genéticos e fenotípicos com os experimentos das famílias S0:1. Constatou-se que houve boa associação (r = 0,81 entre a estimativa de (m + a e a média das famílias S0:1 e que população com maior potencial para a extração de linhagens, maior (m + a, foi a AG 1051. A correlação entre as estimativas de (d e h² foi baixa, indicando que a estimativa da contribuição dos locos em heterozigose não foi bom indicador da variabilidade potencial da população.The identification of the population with greatest potential for inbred line extraction is directly linked to the success of a maize hybrid breeding program. This study was carried out to identify procedures for selecting these populations. Segregant S0, S1 populations and 196 S0:1 families were obtained from each of four commercial cultivars assessed: single hybrids (C 333B and
Szénási, Ágnes; Pálinkás, Zoltán; Zalai, Mihály; Schmitz, Oswald J; Balog, Adalbert
There is concern that genetically modified (GM) plants may have adverse affects on the arthropod biodiversity comprising agricultural landscapes. The present study report on a two year field experimental test of whether four different genotypic lines, some are novel with no previous field tests, of GM maize hybrids alter the structure of arthropod food webs that they harbour, relative to non-GM maize (control) that is widely used in agriculture. The different GM genotypes produced either Bt toxins, conferred glyphosate tolerance or a combination of the two traits. Quantitative food web analysis, based on short-term assessment assigning a total of 243,896 arthropod individuals collected from the treatments to their positions in food webs, revealed that complex and stable food webs persisted in each maize treatment. Moreover, food web structure remained relatively unchanged by the GM-genotype. The results suggest that at least in short-term period these particular GM maize genotypes will not have adverse effects on arthropod biota of agricultural landscapes.
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
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.
Resistance to damage by maize weevil (Sitophilus zeamais Motsch.) is critically important to subsistence farmers who typically store maize grain on-farm. To evaluate grain's antibiosis effects to weevil, 18 inbred lines, six each from Southern Africa, Mexico and CIMMYT-Zimbabwe were mated in sets, according to a North ...
Glauce Cristina Ricardo Rumin
maize populations. It is based on field data and the RFLP genotypes of seed parents. Index usefulness was examined, considering its efficiency for generating synthetics with high QTL frequencies, in contrast with line selection based solely on topcross performance. Seed parents were genotyped for 157 RFLP marker loci with an average distance between loci of 15.30 cM. Sixty-eight S2 lines, stemming from an F2 population derived from a cross between two homozygous inbred lines, were topcrossed and evaluated in four locations in Iowa, USA, in 1996. From these 157 loci, 18 were identified as significantly associated with yield QTLs explaining 74.70 % of the genetic variance among topcross progenies. The proposed index included measures which are function of the per se line behaviour and the genetic complementarity between lines, and led to a diallel table homologue for all parental lines. These properties cannot be accomplished using only the topcross selection criterion. The index led to synthetic populations which are expected to be superior to the best synthetic population selected by topcross performance alone. However, this superiority is valid only for QTL regions covered by the markers used. This procedure allowed a useful monitoring of the genetic constitution of all possible synthetic populations.
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) ...
Full Text Available Background: Global as well as specific expression profiles of selected rat tissues were characterized to assess the safety of genetically modified (GM maize MON810 containing the insecticidal protein Cry1Ab. Gene expression was evaluated by use of Next Generation Sequencing (NGS as well as RT-qPCR within rat intestinal tissues based on mandatory 90-day rodent feeding studies. In parallel to two 90-day feeding studies, the transcriptional response of rat tissues was assessed as another endpoint to enhance the mechanistic interpretation of GM feeding studies and/or to facilitate the generation of a targeted hypothesis. Rats received diets containing 33% GM maize (MON810 or near-isogenic control maize. As a site of massive exposure to ingested feed the transcriptomic response of ileal and colonic tissue was profiled via RT-qPCR arrays targeting apoptosis, DNA-damage/repair, unfolded protein response (UPR. For global RNA profiling of rat ileal tissue, we applied NGS.Results: No biological response to the GM-diet was observed in male and in female rat tissues. Transcriptome wide analysis of gene expression by RNA-seq confirmed these findings. Nevertheless, gene ontology (GO analysis clearly associated a set of distinctly regulated transcripts with circadian rhythms. We confirmed differential expression of circadian clock genes using RT-qPCR and immunoassays for selected factors, thereby indicating physiological effects caused by the time point of sampling.Conclusion: Prediction of potential unintended effects of GM-food/feed by transcriptome based profiling of intestinal tissue presents a novel approach to complement classical toxicological testing procedures. Including the detection of alterations in signaling pathways in toxicity testing procedures may enhance the confidence in outcomes of toxicological trials. In this study, no significant GM-related changes in intestinal expression profiles were found in rats fed GM-maize MON810. Relevant
Sharbati, Jutta; Bohmer, Marc; Bohmer, Nils; Keller, Andreas; Backes, Christina; Franke, Andre; Steinberg, Pablo; Zeljenková, Dagmar; Einspanier, Ralf
Background: Global as well as specific expression profiles of selected rat tissues were characterized to assess the safety of genetically modified (GM) maize MON810 containing the insecticidal protein Cry1Ab. Gene expression was evaluated by use of Next Generation Sequencing (NGS) as well as RT-qPCR within rat intestinal tissues based on mandatory 90-day rodent feeding studies. In parallel to two 90-day feeding studies, the transcriptional response of rat tissues was assessed as another endpoint to enhance the mechanistic interpretation of GM feeding studies and/or to facilitate the generation of a targeted hypothesis. Rats received diets containing 33% GM maize (MON810) or near-isogenic control maize. As a site of massive exposure to ingested feed the transcriptomic response of ileal and colonic tissue was profiled via RT-qPCR arrays targeting apoptosis, DNA-damage/repair, unfolded protein response (UPR). For global RNA profiling of rat ileal tissue, we applied NGS. Results: No biological response to the GM-diet was observed in male and in female rat tissues. Transcriptome wide analysis of gene expression by RNA-seq confirmed these findings. Nevertheless, gene ontology (GO) analysis clearly associated a set of distinctly regulated transcripts with circadian rhythms. We confirmed differential expression of circadian clock genes using RT-qPCR and immunoassays for selected factors, thereby indicating physiological effects caused by the time point of sampling. Conclusion: Prediction of potential unintended effects of GM-food/feed by transcriptome based profiling of intestinal tissue presents a novel approach to complement classical toxicological testing procedures. Including the detection of alterations in signaling pathways in toxicity testing procedures may enhance the confidence in outcomes of toxicological trials. In this study, no significant GM-related changes in intestinal expression profiles were found in rats fed GM-maize MON810. Relevant alterations of
Ear axis weight (EAW) is one of the important agronomic traits in maize (Zea mays L.), related to yield. To understand its genetic basis, a recombinant inbred line (RIL) population, derived from the cross Mo17 × Huangzao4, was used for quantitative trait locus mapping (QTL) for EAW under high and low nitrogen (N) regimes.
Full Text Available Chlorophyll has direct roles on photosynthesis and hence closely relates to capacity for photosynthesis, development and yield of crops. With object to explore the roles of chlorophyll content and its relation with other yield attributing traits a field research was conducted using fourteen early genotypes of maize in RCBD design with three replications. Observations were made for Soil Plant Analysis Development (SPAD reading, ear weight, number of kernel row/ear, number of kernel/row, five hundred kernel weight and grain yield/hectare and these traits were analyzed using Analysis of Variance (ANOVA and correlation coefficient analysis. SPAD reading showed a non-significant variation among the genotypes while it revealed significant correlation with no. of kernel/row, grain yield/hectare and highly significant correlation with no. of kernel row/ear and ear weight which are the most yield determinative traits. For the trait grain yield/ha followed by number of kernel row/ear genotype ARUN-1EV has been found comparatively superior to ARUN-2 (standard check. Grain Yield/hectare was highly heritable (>0.6 while no. of kernel / row, SPAD reading, ear weight, number of kernel row/ear were moderately heritable (0.3-0.6. Correlation analysis and ANOVA revealed ARUN-1EV, comparatively superior to ARUN-2 (standard check, had higher SPAD reading than mean SPAD reading with significant correlation with no. of kernel/row, no. of kernel row/ear, ear weight and grain yield/ha which are all yield determinative traits . This showed positive and significant effect of chlorophyll content in grain yield of the maize.
Macaulay, Babajide Milton; Enahoro, Gloria Ebarunosen
Effects of acid rain on the morphology, phenology and dry biomass of maize (Suwan-1 variety) were investigated. The maize seedlings were subjected to different pH treatments (1.0, 2.0, 3.0, 4.0, 5.0 and 6.0) of simulated acid rain (SAR) with pH 7.0 as the control for a period of 90 days. The common morphological defects due to SAR application were necrosis and chlorosis. It was observed that necrosis increased in severity as the acidity increased whilst chlorosis was dominant as the acidity decreased. SAR encouraged rapid floral and cob growth but with the consequence of poor floral and cob development in pH 1.0 to 3.0 treatments. The result for the dry biomass indicates that pH treatments 2.0 to 7.0 for total plant biomass were not significantly different (P > 0.05) from one another, but were all significantly higher (P acid rain but with pronounced morphological and phenological defects which, however, have the capacity to reduce drastically the market value of the crop. Therefore, it may be concluded that Suwan-1 tolerated acid rain in terms of the parameters studied at pH 4.0 to 7.0 which makes it a suitable crop in acid rain-stricken climes. This research could also serve as a good reference for further SAR studies on maize or other important cereals.
Performance of testers with different genetic structure for evaluation of maize inbred lines Desempenho de testadores com diferentes estruturas genéticas para avaliação de linhagens endogâmicas de milho
Lauro José Moreira Guimarães
Full Text Available The objective of this study was to evaluate four maize testers for identification of superior inbreed lines in testcross. The four testers evaluated are cultivars with narrow or wide genetic base (single-cross hybrids and open pollinated varieties and two kernel types (flint or dent. SynD and SynF testers are open pollinated varieties with dent and flint kernels, respectively, and FSH and DSH testers are single-cross hybrids with flint and dent kernels, respectively. SynD tester showed the biggest genetic variance among the maize inbreed lines in crosses. The effects of general combining ability (GCA for lines and specific combining ability (SCA for lines x testers were significant, whereas GCA effects for testers were not significant. SynD and SynF testers identified the largest number of lines with higher GCA. The DSH and FSH testers showed suitable to identify lines with high SCA. It was concluded that SynD and SynF testers are adequate to identify inbreed lines with high GCA effects, and it's possible to identify new lines with high heterotic potential in each one of the four testers.O objetivo deste estudo foi avaliar quatro testadores de milho quanto à capacidade de identificar linhagens superiores em testcross. Os quatro testadores avaliados são cultivares com base genética ampla (variedades de polinização aberta e estreita (híbridos simples e dois tipos de grãos (duro e dentado. Os testadores SynD e SynF são populações de milho de polinização aberta com grãos dentados e duros, respectivamente, e FSH e DSH são híbridos simples com grãos duros e dentados, respectivamente. O testador SynD possibilitou a maior expressão de variância genética entre os cruzamentos com as linhagens. A capacidade geral de combinação (CGC das linhagens e a capacidade específica de combinação (CEC entre linhagens e testadores foram significativas, enquanto que os efeitos de CGC dos testadores foram não significativos. Concluiu-se que os
... helping in tracking the migration routes of maize from the centers of origin, and understanding the fate of genetic diversity during maize domestication. The genome sequencing of B73 (a highly popular US Corn Belt inbred) and Palomero (a popcorn landrace in Mexico) in the recent years are important landmarks in maize ...
Maize streak virus disease is an important disease of maize in Kenya. In this study, we mapped and characterized quantitative trait loci affecting resistance to maize streak virus in maize populations of S4 families from the cross of one resistant MAL13 and one susceptible MAL9 recombinant inbred lines. Resistance was ...
José Branco de Miranda Filho
for breeding purposes was the objective of this study. Ten maize varieties (populations, previously selected for resistance to Puccinia polysora, Phaeosphaeria maydis, Physopella zeae, Exserohilum turcicum and corn stunt complex, were evaluated under the diallel crossing scheme. Varieties and crosses were evaluated in acid and low fertility soil. Analyzed traits were: ear yield (EY, plant height (PH, and ear height (EH. Varieties PMI 8701, CMS 57NF, PMI 9401 CMS 58ND and AMARILLO DENTADO DMR showed the highest yields (above 3.5 t/ ha per se representing more than 70% in relation to check yield. Heterosis showed significance for all traits, but among the components of heterosis only average heterosis was significant for EY and specific heterosis for EH. General combining ability effects (gi were significant for all traits, and their highest EY estimates (t/ha were for PMI 8701 (0.150, BR 105 (0.120, CMS 59 (0.106. The cross CMS 57NF x PMI 8701, with yield of 5.11 t/ha (above both hybrid checks and heterosis of 23.7% above mid-parent, may be indicated as a potentially useful heterotic group. Varieties PMI 8701, CMS 57NF, PMI 9401 and CMS 58ND were considered the most promising intrapopulation breeding programs, for acid soils.
KEY-WORDS: Heterosis; acidity stress; combining ability; germplasm.
W. Paul Williams; Gary L. Windham
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 comb...
Killi, Dilek; Bussotti, Filippo; Raschi, Antonio; Haworth, Matthew
Heat and drought stress frequently occur together, however, their impact on plant growth and photosynthesis (P N ) is unclear. The frequency, duration and severity of heat and drought stress events are predicted to increase in the future, having severe implications for agricultural productivity and food security. To assess the impact on plant gas exchange, physiology and morphology we grew drought tolerant and sensitive varieties of C3 sunflower (Helianthus annuus) and C4 maize (Zea mays) under conditions of elevated temperature for 4 weeks prior to the imposition of water deficit. The negative impact of temperature on P N was most apparent in sunflower. The drought tolerant sunflower retained ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO) activity under heat stress to a greater extent than its drought sensitive counterpart. Maize exhibited no varietal difference in response to increased temperature. In contrast to previous studies, where a sudden rise in temperature induced an increase in stomatal conductance (G s ), we observed no change or a reduction in G s with elevated temperature, which alongside lower leaf area mitigated the impact of drought at the higher temperature. The drought tolerant sunflower and maize varieties exhibited greater investment in root-systems, allowing greater uptake of the available soil water. Elevated temperatures associated with heat-waves will have profound negative impacts on crop growth in both sunflower and maize, but the deleterious effect on P N was less apparent in the drought tolerant sunflower and both maize varieties. As C4 plants generally exhibit water use efficiency (WUE) and resistance to heat stress, selection on the basis of tolerance to heat and drought stress would be more beneficial to the yields of C3 crops cultivated in drought prone semi-arid regions. © 2016 Scandinavian Plant Physiology Society.
Ana Beatriz Locatelli
Full Text Available O milho é um cereal que faz parte de um grande número de produtos e apresenta produção crescente em nível mundial. A maior parte das áreas produtivas no Brasil são ocupadas por híbridos obtidos a partir de linhagens endogâmicas. Nos anos de 1991/92, foram conduzidos dois experimentos em blocos ao acaso e três repetições, com 36 híbridos de nove linhagens endogâmicas de milho em Não Me Toque e Tapera, ambos locais no Rio Grande do Sul, com o objetivo de avaliar estes híbridos quanto à capacidade combinatória em dois ambientes, para os caracteres altura de inserção da espiga superior, porcentagem de tombamento, prolificidade e rendimento de grãos. A significância da interação C.G.C. e C.E.C. com ambiente, evidenciou as diferenças de comportamento dos genótipos nos dois locais. As linhagens presentes nas melhores combinações foram as mesmas nos dois ambientes, mostrando que a C.G.C. foi um bom indicador do desempenho das linhagens em combinações híbridas, embora os melhores híbridos não tenham sido os mesmos nos dois locais. As linhagens que se destacaram foram ID01, IMD04, IMD06 e ID09.Corn is present in a great number of products and its area and production is growing in the world. In 1991/92 two evaluation trials were conducted in a complete randomised block design and three replications, with 36 hybrids of nine inbred lines in "Não Me Toque" and "Tapera", both in the state of Rio Grande do Sul, with the aim of evaluating the genetic diversity and combining ability of these hybrids for ear height, stalk-root, lodging, prolificacy and grain yield. The significant interaction for CGA and SCA with location showed that the genotypes had different performance in the two environments. The inbred lines in the best combinations were the same at the two locations, showing that the CGA was a good indicator of inbred lines performance at hybrid combinations, although the best hybrids were not the same at the two locations
Geraldo Magela de Almeida Cançado
Full Text Available Avaliaram-se nove linhagens endogâmicas de milho e seus cruzamentos quanto à tolerância ao alumínio (Al, em um dialelo incompleto. Foram utilizados os índices fenotípicos de comprimento relativo de raiz seminal (CRRS, comprimento líquido de raiz seminal (CLRS e coloração por hematoxilina, determinados após sete dias de crescimento em solução nutritiva contendo 222 mimoles L-1 de Al. Os resultados dos cruzamentos dialélicos demonstraram que os efeitos aditivos foram mais importantes que os efeitos não-aditivos para os três índices avaliados. As linhagens L13, L724, L723 e L16 seriam as mais indicadas para a obtenção de híbridos visando tolerância ao Al, por apresentarem os melhores valores de capacidade geral de combinação e por participarem dos cruzamentos de melhor capacidade específica de combinação. Uma correlação de 0,76 foi observada entre os índices CLRS e a coloração por hematoxilina, de 0,63 entre CLRS e CRRS e de 0,27 entre CRRS e coloração por hematoxilina. A coloração por hematoxilina demonstrou ser uma valiosa ferramenta para programas de melhoramento de milho que visam a seleção de genótipos com maior tolerância ao alumínio.Nine maize inbred lines and their hybrid combinations were evaluated in incomplete diallel crosses to study the aluminum (Al tolerance behavior. The phenotypic indexes used to determine Al tolerance were the relative seminal-root length (RSRL, the net seminal-root length (NSRL and the hemathoxylin staining, determined after seven days of growth in nutrient solution with 222 mumoles L-1 of Al. The diallel crosses results showed that additive effects were more important than not additive effects, for all indexes evaluated. Maize lines L13, L724, L723, and L16 showed better behaviour for general combining ability (GCA and specific combining ability (SCA and are the more indicated for obtaining Al-tolerant hybrids. The correlation observed between NSRL and hematoxylin staining
Yan, Jian; Lipka, Alexander E; Schmelz, Eric A; Buckler, Edward S; Jander, Georg
Plants produce a wide variety of defensive metabolites to protect themselves against herbivores and pathogens. Non-protein amino acids, which are present in many plant species, can have a defensive function through their mis-incorporation during protein synthesis and/or inhibition of biosynthetic pathways in primary metabolism. 5-Hydroxynorvaline was identified in a targeted search for previously unknown non-protein amino acids in the leaves of maize (Zea mays) inbred line B73. Accumulation of this compound increases during herbivory by aphids (Rhopalosiphum maidis, corn leaf aphid) and caterpillars (Spodoptera exigua, beet armyworm), as well as in response to treatment with the plant signalling molecules methyl jasmonate, salicylic acid and abscisic acid. In contrast, ethylene signalling reduced 5-hydroxynorvaline abundance. Drought stress induced 5-hydroxynorvaline accumulation to a higher level than insect feeding or treatment with defence signalling molecules. In field-grown plants, the 5-hydroxynorvaline concentration was highest in above-ground vegetative tissue, but it was also detectable in roots and dry seeds. When 5-hydroxynorvaline was added to aphid artificial diet at concentrations similar to those found in maize leaves and stems, R. maidis reproduction was reduced, indicating that this maize metabolite may have a defensive function. Among 27 tested maize inbred lines there was a greater than 10-fold range in the accumulation of foliar 5-hydroxynorvaline. Genetic mapping populations derived from a subset of these inbred lines were used to map quantitative trait loci for 5-hydroxynorvaline accumulation to maize chromosomes 5 and 7. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology.
Coll, A.; Nadal, A.; Collado, R.; Capellades, G.; Kubista, Mikael; Messeguer, J.; Pla, M.
Roč. 73, č. 3 (2010), s. 349-362 ISSN 0167-4412 Institutional research plan: CEZ:AV0Z50520701 Keywords : GMO (Genetically Modified Organism) * MON810 * Maize * Transcriptome Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 4.149, year: 2010
Apr 12, 2012 ... Improved amylose content in maize has been achieved by reducing the starch branching enzyme (SBE) activity via transgenic maize inbred line transformed by a high-efficient RNAi expression vector, which may provide the foundation for maize quality improvement. The sense and anti-sense fragments of.
Maize requires more water than most other crops; therefore, the water use efficiency of this crop must be improved for maize production under undesirable land and changing environmental conditions. To elucidate the genetic control of drought in maize, we evaluated approximately 5000 inbred lines fr...
The maize W22 inbred has served as a platform for maize genetics since the mid twentieth century. To streamline maize genome analyses, we have sequenced and de novo assembled a W22 reference genome using small-read sequencing technologies. We show that significant structural heterogeneity exists in ...
The objective of this study was to identify diverse sources of weevil resistance for introgression in breeding programmes. A total of 180 inbred lines from three geographical areas were screened for maize weevil resistance. Screening was executed by infesting 50 g of maize grain with 32 newly emerged adult weevils, ...
Genetic analysis of japonica x indica recombinant inbred lines and characterization of major fragrance gene by microsatellite markers. ... At some SSR loci, new/recombinant alleles were observed, which indicate the active recombination between genomes of two rice varieties and can be used for linkage mapping once ...
Screening a large number of plants for salinity tolerance is not easy, therefore this investigation was performed to evaluate and screen 186 F8 recombinant inbred lines (RILs) derived from a cross between Superhead#2 (Super Seri) and Roshan wheat varieties for salinity tolerance. All the individuals were evaluated under ...
Amenós, Montse; Corrales, Isabel; Poschenrieder, Charlotte; Illés, Peter; Baluska, Frantisek; Barceló, Juan
A relationship between aluminum (Al) toxicity, endocytosis, endosomes and vesicle recycling in the root transition zone has recently been demonstrated. Here the importance of filamentous actin (F-actin)-based vesicle trafficking for Al tolerance has been investigating in maize varieties differing in their Al sensitivities. More Al was internalized into root tip cells of the Al-sensitive variety 16x36 than in the Al-tolerant variety Cateto. The actin cytoskeleton and vesicle trafficking were primary targets for Al toxicity in the root tips of the sensitive variety. Visualization of boron-cross-linked rhamnogalacturonan II (RGII)-containing brefeldin A (BFA) compartments revealed that Al inhibited the formation of these compartments, especially in variety 16x36. The time sequence of Al effects on pectin recycling matches the growth effects of Al in this sensitive variety. These results support the hypothesis that Al binding to pectin-rich cell walls can contribute to reversible inhibition of root elongation. Al-induced alterations on F-actin were most evident in the central part of the transition zone of Al-sensitive 16x36, where Al was localized inside the nucleoli. In relation to this observation, a role for symplastic Al in both irreversible growth inhibition and amelioration of BFA-induced inhibition of root elongation is discussed.
Full Text Available Sweet corn differs from field corn in many important traits. So its breeding although includes some standard procedures demand application of techniques that are important for determining special traits, all because of the specificity of its usage. Application of molecular markers becomes almost a necessity for the breeding of sweet corn, especially because this is the type of maize in which still no definitive heterotic patterns have been determined. So getting to know genetic divergence of the sweet corn inbred lines is of great importance for its breeding. In this paper we analyzed genetic similarity of six sweet corn inbreds based on SSR markers. 40 SSR primers were used in DNA amplification. Results were compared and correlated with the data on specific combining ability, obtained by the diallel analysis. The results of SCA were in concurrence with genetic similarity. Values of rank correlation coefficient were negative, indicating that more similar inbred lines had smaller estimates of SCA, and lines that were less similar had higher estimates of SCA. Rank correlation coefficient between SCA and GS according to Dice coefficient was between -0,16 and -0,57*.
Fu, Zhongjun; Li, Weihua; Xing, Xiaolong; Xu, Mengmeng; Liu, Xiaoyang; Li, Haochuan; Xue, Yadong; Liu, Zonghua; Tang, Jihua
Arsenic (As) is a toxic heavy metal that can accumulate in crops and poses a threat to human health. The genetic mechanism of As accumulation is unclear. Herein, we used quantitative trait locus (QTL) mapping to unravel the genetic basis of As accumulation in a maize recombinant inbred line population derived from the Chinese crossbred variety Yuyu22. The kernels had the lowest As content among the different maize tissues, followed by the axes, stems, bracts and leaves. Fourteen QTLs were identified at each location. Some of these QTLs were identified in different environments and were also detected by joint analysis. Compared with the B73 RefGen v2 reference genome, the distributions and effects of some QTLs were closely linked to those of QTLs detected in a previous study; the QTLs were likely in strong linkage disequilibrium. Our findings could be used to help maintain maize production to satisfy the demand for edible corn and to decrease the As content in As-contaminated soil through the selection and breeding of As pollution-safe cultivars.
Starr, J. L.; Yang, W.; Yan, Y.; Crutcher, F.; Kolomiets, M.
Maize is a well-known host for Meloidogyne incognita, and there is substantial variation in host status among maize genotypes. In previous work it was observed that nematode reproduction increased in the moderately susceptible maize inbred line B73 when the ZmLOX3 gene from oxylipid metabolism was knocked out. Additionally, in this mutant line, use of a nonspecific primer for phenyl alanine ammonialyase (PAL) genes indicated that expression of these genes was reduced in the mutant maize plant...
Full Text Available Os objetivos deste trabalho foram determinar as capacidades geral e específica de combinação entre variedades locais e sintéticas de milho e identificar cruzamentos que reúnam características de interesse agronômico, com vistas à síntese de variedades. O dialelo parcial foi realizado com 11 variedades sintéticas cruzadas com cinco variedades locais do Paraná. As combinações híbridas resultantes foram avaliadas juntamente com as cinco variedades locais genitoras e com cinco híbridos comerciais, em blocos completos ao acaso com quatro repetições, em São João do Triunfo e Londrina, PR. Houve interação genótipo x local para a maioria dos caracteres avaliados, com predominância da interação da capacidade geral de combinação x local. As melhores estimativas de capacidade geral de combinação do grupo dos sintéticos foram observadas para ST09 e ST04 e, no grupo das variedades, para MC45 e IAPAR 50, considerando-se o conjunto das características e de locais. As melhores combinações híbridas (MC34 x ST04, IAPAR 50 x ST07, MC47 x ST09, MC45 x ST02, MC51 x ST04 e MC45 x ST01 apresentaram estimativas positivas de capacidade específica de combinação quanto à produtividade, em ambos os locais. Existem combinações híbridas com potencial para síntese de novas variedades com padrões de produtividade, altura de planta, posição relativa da espiga e percentagem de espigas danificadas e de plantas acamadas e quebradas melhores que os observados em variedades locais per se e mais semelhantes aos dos híbridos comerciais.The objectives of this work were to determine the general and specific combining ability between landraces and synthetic varieties of maize and to identify the crosses that combine important agronomic traits, to develop new maize varieties. A partial diallel was done with 11 synthetic varieties crossed with five landraces. The crosses were evaluated along with the five parental landraces and five commercial
Maria Elisa Ayres Guidetti Zagatto Paterniani
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With the objective of identifying the best commercial hybrids to extract maize lines, a top cross scheme of 49 endogamic partial lines (S3 was carried out with the IA33 tester. The resultant hybrids were evaluated for grain yield, in Campinas, Mococa, and Palmital (São Paulo State, Brazil, in two agricultural years (2005/2006 and 2006/2007, in a randomized block design, with three replications, in two experiments (TC1 and TC2. Individual and group variance analysis and a grouped analysis of the experiments with common treatments were carried out, for each place. The top cross hybrids were grouped according to the line origins. Afterwards, orthogonal contrasts were carried out by using the Student’s t test, in order to compare the hybrid groups. It was verified that the use of commercial hybrids to extract lines is an interesting strategy. In general, it was also verified that the top cross hybrid groups, whose lines originated from the AG1051, Master, and XL357 hybrids, obtained high yield, with a higher potential for lines extraction.
KEY-WORDS: Zea mays L.; top cross hybrids; partially endogamic lines (S3.
O presente trabalho teve por objetivo identificar os melhores híbridos comerciais para extração de linhagens de milho. Para isto, foram
Huang, Q; Gao, S B; Zhang, Z M; Lin, H J; Pan, G T; Yang, K C; Rong, T Z
An elite maize inbred line with high tolerance to low phosphorus, 178, was studied for constructing root library and analyzing some genes closely related to phosphorus (P) deficiency using SSH and Semi-quantitative RT-PCR. As a result, 3648 preliminary clones were obtained for root library under stress of P deficiency. By DNA sequencing of 34 random clones, we obtained 23 unique EST sequences which are involved in functions of root cell structure, tolerance and defense, protein modification and composition, transcription regulation, metabolism, and other unknown aspects. Five representative genes were further analyzed for their expression models. The results suggested that the molecular mechanism to adapt P deficiency in maize, performed by multi-genes with different contributions, is similar to rice, Arabidopsis and soybean. The expression order of 5 low P tolerant genes in maize root was PAP, GCS, TOM, PDI and AIP. And it was considered preliminarily that physiological and biochemical changes were prior to morphologic changes in maize root and the essential tolerance to low P may be determined by extending absorption of P to wide soil range through adaption of root architecture and root secretions, which is the greatest difference between tolerant and sensitive maize varieties under low P stress.
Alhassan D. Halilu
Full Text Available Yellow maize contains high levels of β-carotene (βC, making it an important crop for combating vitamin A deficiency through biofortification. In this study, nine maize inbred lines were selected at random from 31 provitamin A (PVA maize inbred lines and crossed in a partial diallel mating design to develop 36 crosses. The crosses were evaluated in the field in two locations (Samaru and Kerawa and their seed carotenoid content were determined by high-performance liquid chromatography. The modes of gene action, heritability, and correlations between agronomic traits and carotenoid content were estimated. Additive genetic variances (σ2a were lower than non-additive genetic variances (σ2d for all the carotenoids, plant height (PH, and grain yield (GY, suggesting a preponderance of non-additive gene action. Broad-sense heritability (H2 was high (H2 > 60% for zeaxanthin, days to anthesis, and PH, moderate (30% < H2 < 60% for lutein and GY, and low (H2 < 30% for alpha carotene, beta cryptoxanthin, βC, and PVA. Genetic advance as a percentage of mean, considered with H2, also suggests a preponderance of non-additive gene action for PVA carotenoids. Hybrid variety development is thus an appropriate approach to improving grain yield and PVA. GY showed no significant genotypic correlations with carotenoid content, suggesting that these traits can be improved concurrently. Thus, there is ample scope for improvement of PVA and GY in the sample of tropical-adapted maize.
Full Text Available Abstract. In this study, chromosome elimination method was used to develop doubled haploid wheat lines via crosses with maize. The plant materials used included 11, F1 wheat genotypes and maize genotype BC572. In these crosses, the maize plant was used as the male parent.Three methods of haploid production in wheat comprising conventional (A, detached-tiller culture (B and intermediate (C techniques were used and compared. The traits such as the number of seeds set, the number of embryos obtained and the number of haploid seedlings produced were studied. Comparisons showed that among various methods of storing wheat spikes, method (C was better than other techniques in terms of the percentage of seed production, embryo formation and haploid seedling production. Also, in all three methods, the percentage of seed production, the percentage of embryo formation and the percentage of haploid seedling production were respectively equal to 76.84, 25.22 and 51.89. Among the wheat genotypes in all three methods, genotype DH-133 with 87.28 percent seed set and genotype DH-132 with 32.71 percent embryo formation and 65.08 percent haploid seedling production were the best genotypes. A total of 92 doubled haploid lines were produced. In the field evaluations of 86 doubled haploid lines, traits such as growing season, plant height, lodging, kernel yield and 1000 kernel weight were examined. Finally, 3 lines were selected for adaptation and stability testing under heat stress conditions.Keywords: Wheat, Doubled haploid, Chromosome elimination, Detached-tiller culture Özet. Bu çalışmada, mısır ile çaprazlarla çift katlı haploid buğday hatlarının geliştirilmesi için kromozom eliminasyon yöntemi kullanılmıştır. Kullanılan bitki materyalleri 11, F1 buğday genotipleri ve BC572 mısır genotipini içermektedir. Bu çaprazlarda, mısır bitkisi erkek ebeveyn olarak kullanılmıştır. Geleneksel (A, ayrık-yeke kültürü (B ve ara (C
N-partitioning, nitrate reductase and glutamine synthetase activities in two contrasting varieties of maize Partição de nitrogênio e atividade das enzimas nitrato redutase e glutamina sintetase em duas cultivares contrastantes de milho
Altair Toledo Machado
Full Text Available In order to identify useful parameters for maize genetic breeding programs aiming at a more efficient use of N, two maize varieties of contrasting N efficiency, Sol da Manhã NF (efficient and Catetão (inefficient were compared. Experiments were carried out under field and greenhouse conditions, at low and high N levels. The parameters analysed included total and relative plant and grain N content, biomass and the activities of nitrate reductase and glutamine synthetase in different parts of the plant. It was found that the translocation efficiency of N and photoassimilates to the developing seeds and the source-sink relations were significantly different for the two varieties. N content of the whole plant and grain, cob weight and the relative ear dry weight were useful parameters for characterizing the variety Sol da Manhã NF as to its efficient use of N. Enzymes activity of glutamine synthetase (transferase reaction and nitrate reductase did not differ among the varieties.Com o objetivo de identificar parâmetros que possam ser utilizados em programas de melhoramento genético em milho para uso eficiente de N, duas cultivares de milho contrastantes quanto ao uso deste nutriente, Sol da Manhã NF (eficiente e Catetão (não-eficiente, foram avaliadas em dois experimentos conduzidos no campo e em casa de vegetação, respectivamente, sob nível baixo e alto de N. Os caracteres avaliados foram: teor e conteúdo de N em diferentes partes da planta; massa seca; peso dos grãos e de diferentes partes da planta; biomassa, e atividade das enzimas nitrato redutase e glutamina sintetase. O mecanismo de translocação de N e de fotoassimilados para os grãos e a relação fonte/dreno foram importantes para diferenciar a cultivar eficiente da não-eficiente. Conteúdo de N nos grãos e total das plantas, peso do sabugo e relação peso de espiga/matéria seca foram importantes para caracterizar a cultivar Sol da Manhã NF eficiente no uso do N. A
Zheng, Hongjian; Wang, Hui; Yang, Hua; Wu, Jinhong; Shi, Biao; Cai, Run; Xu, Yunbi; Wu, Aizhong; Luo, Lijun
Waxy maize (Zea mays L. var. certaina Kulesh), with many excellent characters in terms of starch composition and economic value, has grown in China for a long history and its production has increased dramatically in recent decades. However, the evolution and origin of waxy maize still remains unclear. We studied the genetic diversity of Chinese waxy maize including typical landraces and inbred lines by SSR analysis and the results showed a wide genetic diversity in the Chinese waxy maize germplasm. We analyzed the origin and evolution of waxy maize by sequencing 108 samples, and downloading 52 sequences from GenBank for the waxy locus in a number of accessions from genus Zea. A sharp reduction of nucleotide diversity and significant neutrality tests (Tajima’s D and Fu and Li’s F*) were observed at the waxy locus in Chinese waxy maize but not in nonglutinous maize. Phylogenetic analysis indicated that Chinese waxy maize originated from the cultivated flint maize and most of the modern waxy maize inbred lines showed a distinct independent origin and evolution process compared with the germplasm from Southwest China. The results indicated that an agronomic trait can be quickly improved to meet production demand by selection. PMID:23818949
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.
De La Fuente, Gerald N.; Carstensen, Jens Michael; Adsetts Edberg Hansen, Michael
and (ii) doubling of the haploid genome to produce fertile inbred lines. This study is focused on the first step. Currently, identification of maize haploid progeny is performed manually using the R1-nj seed colour marker. This is a labour-intensive and time-consuming process; a method for automated......The use of doubled haploids (DHs) in maize has become ubiquitous in maize breeding programmes as it allows breeders to go from cross to evaluation in as little as 2Â years. Two important aspects of the inÂ vivo DH system used in maize are as follows: (i) the identification of haploid progeny...
Butrón, Ana; Santiago, Rogelio; Mansilla, Pedro; Pintos-Varela, Cristina; Ordas, Amando; Malvar, Rosa Ana
Fusarium moniliforme and Fusarium proliferatum are the most frequently isolated fungi from maize (Zea mays L.) in Spain. Both Fusarium species produce toxins potentially dangerous for animals and humans, the fumonisins being the most significant of those toxins. White maize is preferred for human consumption, and extra care should be taken to avoid kernel mycotoxin contamination. The objectives of this study were to identify and quantify kernel infection by Fusarium spp. and contamination by fumonisin on white maize hybrids, to search for white maize sources of resistance to infection by Fusarium spp. and mycotoxin contamination, and to preliminarily study the genetics involved in such resistances. Ten F(1) single crosses derived from a diallel mating design among five white maize inbreds were evaluated in a randomized complete block design with three replications in 2002 at two locations. Fusarium verticilloides and F. proliferatum were detected on kernels of white maize hybrids cultivated in northwestern Spain. No differences in fungal infection were found among maize genotypes, but differences in fumonisin contamination were significant and could be related, in part, to differences in husk tightness. Among the genotypes studied, general combining ability (GCA) effects were the most important for resistance to fumonisin contamination. Inbreds EP10 and EC22 showed the most favorable GCA effects for husk tightness and fumonisin content, and the cross between them, EP10 x EC22, had the most favorable specific combining ability (SCA) effect for husk tightness. Inbreds EP10 and EC22 showed favorable GCA effects for fumonisin contamination and husk tightness, and the cross EP10 x EC22 was the only one with an average fumonisin level below 1 mug/g. Although this should be confirmed with more extensive studies, white maize inbreds developed from white maize landraces could be sources of resistance to fumonisin contamination.
Apr 17, 2008 ... 2Department of Biochemistry and Biotechnology, Kenyatta University, P.O. Box 43844-00100, Nairobi, Kenya. Accepted 15 ... as explants to initiate callus on solid N6 basal media with varying level of 2,4-D (0 - 20 mg L-1) and regenerated on ... lopment of modest increments in yields and agronomic.
Generally, the magnitude of mean squares due to GCA of lines was higher than that of the SCA in most of the cases, indicating that additive gene actions were more important than non-additive with regard to inheritance of the traits studied. Keywords: Combining Ability; Gene Action; Heterotic Pattern; Zea mays. East African ...
One thousand and forty three (1043) maize genotypes including white and yellow maize inbred lines as well as hybrids from the public germplasm collection were characterized with 80 microsatellite markers distributed throughout the genome. A total of 1874 alleles were amplified and used in the genetic diversity analysis.
African Journal of Biotechnology Vol. 11(30), pp. 7628-7637, 12 April, 2012 ... Improved amylose content in maize has been achieved by reducing the starch branching enzyme (SBE) activity via transgenic maize inbred line ... applied in the area of unknown genetic function in both plants and animals, and in the area of crop ...
Li, L.; Vuichard, N.; Viovy, N.; Ciais, P.; Ceschia, E.; Jans, W.; Wattenbach, M.; Béziat, P.; Gruenwald, T.; Lehuger, S.; Bernhofer, C.
Crop varieties and management practices such as planting and harvest dates, irrigation, and fertilization have important effects on the water and carbon fluxes over croplands, and lack or inaccuracy of this information may cause large uncertainties in hydraulic and carbon modeling. Yet the magnitude of uncertainties has not been investigated in detail. This paper provides a comprehensive assessment of the performances of a process-based ecosystem model called ORCHIDEE-STICS (a coupled model between generic ecosystem model ORCHIDEE and the crop growth model STICS), against eddy-covariance observations of CO2 and H2O fluxes at five European maize cultivation sites. The results show that ORCHIDEE-STICS has a good potential to simulate energy, water vapor and carbon dioxide fluxes from maize croplands on a daily basis. The model explains 23-75% of the observed daily net ecosystem exchange (NEE) variance at five sites, and 26-79% of the latent heat flux (LE) variance. Similarly, 34-83% of the variance in observed gross primary productivity (GPP) is accounted for by the model. However, only 3-81% of the variance of observed terrestrial ecosystem respiration (TER) is explained. Therefore, simulating TER is shown to be much more difficult than GPP. We conclude that structural deficiencies of the model in the determination of LAI and TER are the main sources of errors in simulating carbon dioxide and water vapor fluxes. A group of sensitivity analyses, by setting different crop variety, nitrogen fertilization, irrigation, and planting date, indicate that any of these factors is able to cause more than 15% change in simulated NEE although the response of these fluxes to management parameters is site-dependent. Varying management practice in the model is shown to affect not only the daily values of NEE and LE, but also the total seasonal cumulative values, and therefore the annual carbon and water budgets. However, LE is found to be less sensitive to management practices than
Melchinger Albrecht E
Full Text Available Abstract Background The importance of maize for human and animal nutrition, but also as a source for bio-energy is rapidly increasing. Maize yield is a quantitative trait controlled by many genes with small effects, spread throughout the genome. The precise location of the genes and the identity of the gene networks underlying maize grain yield is unknown. The objective of our study was to contribute to the knowledge of these genes and gene networks by transcription profiling with microarrays. Results We assessed the grain yield and grain dry matter content (an indicator for early maturity of 98 maize hybrids in multi-environment field trials. The gene expression in seedlings of the parental inbred lines, which have four different genetic backgrounds, was assessed with genome-scale oligonucleotide arrays. We identified genes associated with grain yield and grain dry matter content using a newly developed two-step correlation approach and found overlapping gene networks for both traits. The underlying metabolic pathways and biological processes were elucidated. Genes involved in sucrose degradation and glycolysis, as well as genes involved in cell expansion and endocycle were found to be associated with grain yield. Conclusions Our results indicate that the capability of providing energy and substrates, as well as expanding the cell at the seedling stage, highly influences the grain yield of hybrids. Knowledge of these genes underlying grain yield in maize can contribute to the development of new high yielding varieties.
Full Text Available To identify and develop drought tolerant maize (Zea mays L., high-throughput and cost-effective screening methods are needed. In dicot crops, measuring survival and recovery of seedlings has been successful in predicting drought tolerance but has not been reported in C4 grasses such as maize. Seedlings of sixty-two diverse maize inbred lines and their hybrid testcross progeny were evaluated for germination, survival and recovery after a series of drought cycles. Genotypic differences among inbred lines and hybrid testcrosses were best explained approximately 13 and 18 days after planting, respectively. Genotypic effects were significant and explained over 6% of experimental variance. Specifically three inbred lines had significant survival, and 14 hybrids had significant recovery. However, no significant correlation was observed between hybrids and inbreds (R2 = 0.03, indicating seedling stress response is more useful as a secondary screening parameter in hybrids than in inbred lines per se. Field yield data under full and limited irrigation indicated that seedling drought mechanisms were independent of drought responses at flowering in this study.
Jun 17, 2003 ... This study compared two maize populations, ZM601 and. ZM607 for drought tolerance during flowering, the most drought-vulnerable period for the maize plant. Cultivar. ZM601 had been improved through ...... Banziger, M., Pixley, K.V. and Zambezi, B.T.. 1999. Drought andNstress tolerance of maize.
The maize genetic resource collection managed by the USDA-ARS's National Plant Germplasm System is heavily utilized by researchers and educators. A collection of landraces, inbred lines from public and private sector sources, synthetics and key populations, it serves both as a living snapshot of th...
W. Paul Williams
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.
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...
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 ...
Physical properties such as germination capacity, hydration capacity, floater test and thousand-grain weight differed significantly (P≤ 0.05) among the selected varieties. The suitability of the maize grain varieties to processing and production of different maize based food products were highlighted. Key words: Maize ...
Nov 13, 2017 ... Earth cultivates maize commercially for a variety of uses. Currently, the United States, China,. Brazil, Mexico, Argentina, India, France, .... AAS, Germany) equipped with deuterium arc back ground connectors and hollow cathode lamps with air-acetylene flame was used for the analysis of the analyte metals.
Massman, Jon M; Gordillo, Andres; Lorenzana, Robenzon E; Bernardo, Rex
Maize (Zea mays L.) breeders evaluate many single-cross hybrids each year in multiple environments. Our objective was to determine the usefulness of genomewide predictions, based on marker effects from maize single-cross data, for identifying the best untested single crosses and the best inbreds within a biparental cross. We considered 479 experimental maize single crosses between 59 Iowa Stiff Stalk Synthetic (BSSS) inbreds and 44 non-BSSS inbreds. The single crosses were evaluated in multilocation experiments from 2001 to 2009 and the BSSS and non-BSSS inbreds had genotypic data for 669 single nucleotide polymorphism (SNP) markers. Single-cross performance was predicted by a previous best linear unbiased prediction (BLUP) approach that utilized marker-based relatedness and information on relatives, and from genomewide marker effects calculated by ridge-regression BLUP (RR-BLUP). With BLUP, the mean prediction accuracy (r(MG)) of single-cross performance was 0.87 for grain yield, 0.90 for grain moisture, 0.69 for stalk lodging, and 0.84 for root lodging. The BLUP and RR-BLUP models did not lead to r(MG) values that differed significantly. We then used the RR-BLUP model, developed from single-cross data, to predict the performance of testcrosses within 14 biparental populations. The r(MG) values within each testcross population were generally low and were often negative. These results were obtained despite the above-average level of linkage disequilibrium, i.e., r(2) between adjacent markers of 0.35 in the BSSS inbreds and 0.26 in the non-BSSS inbreds. Overall, our results suggested that genomewide marker effects estimated from maize single crosses are not advantageous (cofmpared with BLUP) for predicting single-cross performance and have erratic usefulness for predicting testcross performance within a biparental cross.
Quantitative traits result from the influence of multiple genes (quantitative trait loci) and environmental factors. Detecting and mapping the individual genes underlying such 'complex' traits is a difficult task. Fortunately, populations obtained from crosses between inbred lines are relatively
Virus-induced gene silencing (VIGS) is a widely used tool for gene function studies in many plant species, though its use in monocots has been limited. Using a Brome mosaic virus (BMV) vector designed to silence the maize phytoene desaturase gene, a genetically diverse set of maize inbred lines was ...
Both insufficient and excessive male inflorescence size leads to a reduction in maize yield. Knowledge of the genetic architecture of male inflorescence is essential to achieve the optimum inflorescence size for maize breeding. In this study, we used approximately eight thousand inbreds, including b...
Li, L.; Vuichard, N.; Viovy, N.; Ciais, P.; Wang, T.; Ceschia, E.; Jans, W.; Wattenbach, M.; Béziat, P.; Gruenwald, T.; Lehuger, S.; Bernhofer, C.
This paper is a modelling study of crop management impacts on carbon and water fluxes at a range of European sites. The model is a crop growth model (STICS) coupled with a process-based land surface model (ORCHIDEE). The data are online eddy-covariance observations of CO2 and H2O fluxes at five European maize cultivation sites. The results show that the ORCHIDEE-STICS model explains up to 75 % of the observed daily net CO2 ecosystem exchange (NEE) variance, and up to 79 % of the latent heat flux (LE) variance at five sites. The model is better able to reproduce gross primary production (GPP) variations than terrestrial ecosystem respiration (TER) variations. We conclude that structural deficiencies in the model parameterizations of leaf area index (LAI) and TER are the main sources of error in simulating CO2 and H2O fluxes. A number of sensitivity tests, with variable crop variety, nitrogen fertilization, irrigation, and planting date, indicate that any of these management factors is able to change NEE by more than 15 %, but that the response of NEE to management parameters is highly site-dependent. Changes in management parameters are found to impact not only the daily values of NEE and LE, but also the cumulative yearly values. In addition, LE is shown to be less sensitive to management parameters than NEE. Multi-site model evaluations, coupled with sensitivity analysis to management parameters, thus provide important information about model errors, which helps to improve the simulation of CO2 and H2O fluxes across European croplands.
Full Text Available This paper is a modelling study of crop management impacts on carbon and water fluxes at a range of European sites. The model is a crop growth model (STICS coupled with a process-based land surface model (ORCHIDEE. The data are online eddy-covariance observations of CO2 and H2O fluxes at five European maize cultivation sites. The results show that the ORCHIDEE-STICS model explains up to 75 % of the observed daily net CO2 ecosystem exchange (NEE variance, and up to 79 % of the latent heat flux (LE variance at five sites. The model is better able to reproduce gross primary production (GPP variations than terrestrial ecosystem respiration (TER variations. We conclude that structural deficiencies in the model parameterizations of leaf area index (LAI and TER are the main sources of error in simulating CO2 and H2O fluxes. A number of sensitivity tests, with variable crop variety, nitrogen fertilization, irrigation, and planting date, indicate that any of these management factors is able to change NEE by more than 15 %, but that the response of NEE to management parameters is highly site-dependent. Changes in management parameters are found to impact not only the daily values of NEE and LE, but also the cumulative yearly values. In addition, LE is shown to be less sensitive to management parameters than NEE. Multi-site model evaluations, coupled with sensitivity analysis to management parameters, thus provide important information about model errors, which helps to improve the simulation of CO2 and H2O fluxes across European croplands.
Full Text Available The objective was to select maize (Zea mays L. lines, based on the effects of general combining ability (GCA, specific combining ability (SCA and heterosis, for the formation of single crosses. During the spring-summer 2008 cycle, 120 single crosses with the combination of 16 lines of white grain maize were evaluated. To estimate the GCA and SCA effects, the method IV, model I of Griffing's method, was used, in an alpha lattice design with two 16 x 8 repetitions. The results revealed that there are lines with good GCA: LRB-14RC2-1-1, LT-154RC2-1-2, LT-155RC2-1-1, VS-536RC2-1-1, VS-536RC2-1-1, CML-264Q and CML-159.Â The crosses LT-155RC2-1-1xVS-536RC2-1-1, CABGRC2-1-3xD-539RC2-1-1 and D-539RC2-1-1xCML-159 showed the greatest effects of SCA. Of the inbred lines evaluated, LRB-14RC2-1-1, LT-154RC2-1-2, LT-155RC2-1-1, VS-536RC2-1-1, VS-536RC2-1-1, FAM. V-537C, CML-264Q and CML-159 showed the greatest varietal effect values, considering that there is greater additive gene action and that formation of synthetic varieties is possible. The crosses LT155RC2-1-1xVS536RC2-1-1, CABGRC2-1-3xD-539RC2-1-1 and D-539RC2-1-1xCML-159 showed high ACE effects and high heterosis levels, adequate for the formation of maize hybrids. The use of diallel designs to estimate GCA and SCA in inbred lines and their crosses allowed knowing the most efficient breeding method.
Liu, Xu; Jia, Shi-qiang; Wang, Chun-ying; Liu, Zhe; Gu, Jian-cheng; Zhai, Wei; Li, Shao-ming; Zhang, Xiao-dong; Zhu, De-hai; Huang, Hua-jun; An, Dong
This paper explored the relationship among genetic distances, NIR spectra distances and NIR-based identification model performance of the seeds of maize inbred lines. Using 3 groups (total 15 pairs) of maize inbred lines whose genetic distaches are different as experimental materials, we calculates the genetic distance between these seeds with SSR markers and uses Euclidean distance between distributed center points of maize NIR spectrum in the PCA space as the distances of NIR spectrum. BPR method is used to build identification model of inbred lines and the identification accuracy is used as a measure of model identification performance. The results showed that, the correlation of genetic distance and spectra distancesis 0.9868, and it has a correlation of 0.9110 with the identification accuracy, which is highly correlated. This means near-Infrared spectrum of seedscan reflect genetic relationship of maize inbred lines. The smaller the genetic distance, the smaller the distance of spectrum, the poorer ability of model to identify. In practical application, near infrared spectrum analysis technology has the potential to be used to analyze maize inbred genetic relations, contributing much to genetic breeding, identification of species, purity sorting and so on. What's more, when creating a NIR-based identification model, the impact of the maize inbred lines which have closer genetic relationship should be fully considered.
Luciene Fróes Camarano
;">PALAVRAS-CHAVE: Análise AMMI; genótipos vencedores; interação GxA; adaptabilidade; zoneamento.
The objective of this study was to identify environmental strata for maize varieties recommendation and key locations for this kind of trial in Goiás State, Brazil. Forty-seven trials from the maize varieties evaluation program, carried out at Secretaria da Agricultura, Pecuária e Abastecimento do Estado de Goiás (Seagro-GO, over four growing seasons (2002/2003, 2003/2004, 2004/2005, and 2005/2006 were evaluated. The environmental stratification was performed by using the winner genotypes AMMI approach, which allows, due to the study of genotypes by environment interactions (GxE, the identification of the genotypes most adapted to each environment, as well as the constitution of similar environmental location groups. Two environmental strata showed stability throughout the evaluated growing seasons, mainly for the group formed by the locations of Ipameri, Inhumas and Senador Canêdo, stable along the four years, and the one composed by Porangatu and Orizona, stable throughout three growing years. From that, it is possible to reduce at least 16% of the currently used test locations and/or replace them by other locations, aiming to increase the efficiency of the varietal evaluation in that region. The ALBandeirante cultivar showed high yield potential and adaptability to the maize crop conditions in Goiás.
We define a nontrivial variety of boolean algebras with operators such that every member of the variety is atomless. This shows that not every variety of boolean algebras with operators is generated by its atomic members, and thus establishes a strong incompleteness result in (multi-)modal logic.
Ola T Westengen
Full Text Available BACKGROUND: Climate change threatens maize productivity in sub-Saharan Africa. To ensure food security, access to locally adapted genetic resources and varieties is an important adaptation measure. Most of the maize grown in Africa is a genetic mix of varieties introduced at different historic times following the birth of the trans-Atlantic economy, and knowledge about geographic structure and local adaptations is limited. METHODOLOGY: A panel of 48 accessions of maize representing various introduction routes and sources of historic and recent germplasm introductions in Africa was genotyped with the MaizeSNP50 array. Spatial genetic structure and genetic relationships in the African panel were analysed separately and in the context of a panel of 265 inbred lines representing global breeding material (based on 26,900 SNPs and a panel of 1127 landraces from the Americas (270 SNPs. Environmental association analysis was used to detect SNPs associated with three climatic variables based on the full 43,963 SNP dataset. CONCLUSIONS: The genetic structure is consistent between subsets of the data and the markers are well suited for resolving relationships and admixture among the accessions. The African accessions are structured in three clusters reflecting historical and current patterns of gene flow from the New World and within Africa. The Sahelian cluster reflects original introductions of Meso-American landraces via Europe and a modern introduction of temperate breeding material. The Western cluster reflects introduction of Coastal Brazilian landraces, as well as a Northeast-West spread of maize through Arabic trade routes across the continent. The Eastern cluster most strongly reflects gene flow from modern introduced tropical varieties. Controlling for population history in a linear model, we identify 79 SNPs associated with maximum temperature during the growing season. The associations located in genes of known importance for abiotic stress
Maud I. Tenaillon
Full Text Available Little is known about the factors driving within species Genome Size (GS variation. GS may be shaped indirectly by natural selection on development and adaptative traits. Because GS variation is particularly pronounced in maize, we have sampled 83 maize inbred lines from three well described genetic groups adapted to contrasted climate conditions: inbreds of tropical origin, Flint inbreds grown in temperate climates, and Dent inbreds distributed in the Corn Belt. As a proxy for growth rate, we measured the Leaf Elongation Rate maximum during nighttime (LERmax as well as GS in all inbred lines. In addition we combined available and new nucleotide polymorphism data at 29,090 sites to characterize the genetic structure of our panel. We found significant variation for both LERmax and GS among groups defined by our genetic structuring. Tropicals displayed larger GS than Flints while Dents exhibited intermediate values. LERmax followed the opposite trend with greater growth rate in Flints than in Tropicals. In other words, LERmax and GS exhibited a significantly negative correlation (r = − 0.27. However, this correlation was driven by among-group variation rather than within-group variation—it was no longer significant after controlling for structure and kinship among inbreds. Our results indicate that selection on GS may have accompanied ancient maize diffusion from its center of origin, with large DNA content excluded from temperate areas. Whether GS has been targeted by more intense selection during modern breeding within groups remains an open question.
Ranum, Peter; Peña-Rosas, Juan Pablo; Garcia-Casal, Maria Nieves
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.
The maize weevil (Sitophilus zeamais Motschulsky) is the most destructive storage insect pest of maize (Zea mays L.) worldwide, especially among susceptible varieties. Breeding for grain resistance against the weevil is a major component of an integrated pest management strategy in maize production. The objective of ...
In recent years, the use of quality protein maize (QPM) with the objective of improving the nutritional value of maize grain protein has been the focus of several African breeding programs. Knowledge of genetic variation among QPM and normal maize varieties is important for an efficient selection and development of new ...
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- ...
Full Text Available Popping volume and yield are traits caused by several heredity factors. It is difficult to obtain superior genotypes for both traits but it is possible to develop genotypes with good popping volume and satisfactory yield. The hybrid ZPPL2 x ZPPL5 was superior in yield, heterosis and SCA for both yield and popping volume. As inbred ZPPL4 in all combinations has a good value for popping volume could be concluded that this inbred may be used as parent in further crosses. Analysis of variance of the combining ability indicating significant SCA effect for grain yield, and significant both GCA and SCA effects for popping volume. Therefore it can be stated that yield is influenced by non-additive and popping volume by both additive and non- additive gene effects. Analysis of variance of genetic components for popping volume indicates that the additive as well as dominant components significantly affected the inheritance of this trait in popcorn. The objective of this study was to evaluate heteorsis and combing ability for grain yield and popping volume in dialalel set of six maize inbred lines.
Hochholdinger, Frank; Marcon, Caroline; Baldauf, Jutta A; Yu, Peng; Frey, Felix P
Maize forms a complex root system with structurally and functionally diverse root types that are formed at different developmental stages to extract water and mineral nutrients from soil. In recent years proteomics has been intensively applied to identify proteins involved in shaping the three-dimensional architecture and regulating the function of the maize root system. With the help of developmental mutants, proteomic changes during the initiation and emergence of shoot-borne, lateral and seminal roots have been examined. Furthermore, root hairs were surveyed to understand the proteomic changes during the elongation of these single cell type structures. In addition, primary roots have been used to study developmental changes of the proteome but also to investigate the proteomes of distinct tissues such as the meristematic zone, the elongation zone as well as stele and cortex of the differentiation zone. Moreover, subcellular fractions of the primary root including cell walls, plasma membranes and secreted mucilage have been analyzed. Finally, the superior vigor of hybrid seedling roots compared to their parental inbred lines was studied on the proteome level. In summary, these studies provide novel insights into the complex proteomic interactions of the elaborate maize root system during development.
Full Text Available Maize forms a complex root system with structurally and functionally diverse root types that are formed at different developmental stages to extract water and mineral nutrients from soil. In recent years proteomics has been intensively applied to identify proteins involved in shaping the three-dimensional architecture and regulating the function of the maize root system. With the help of developmental mutants, proteomic changes during the initiation and emergence of shoot-borne, lateral and seminal roots have been examined. Furthermore, root hairs were surveyed to understand the proteomic changes during the elongation of these single cell type structures. In addition, primary roots have been used to study developmental changes of the proteome but also to investigate the proteomes of distinct tissues such as the meristematic zone, the elongation zone as well as stele and cortex of the differentiation zone. Moreover, subcellular fractions of the primary root including cell walls, plasma membranes and secreted mucilage have been analyzed. Finally, the superior vigor of hybrid seedling roots compared to their parental inbred lines was studied on the proteome level. In summary, these studies provide novel insights into the complex proteomic interactions of the elaborate maize root system during development.
Eijnatten, van C.L.M.
Approximately 600,000 tons of maize were produced annually in Nigeria. Maize was the main grain crop in southern Nigeria and its production in the middle belt was rapidly increasing. Most of the crop was eaten as dry grain, a little before maturity. A preference was recorded for floury varieties of
Comportamento de cultivares de milho quanto ao rendimento e susceptibilidade a pragas e doenças na província do Huambo (Angola Behaviour of maize varieties concerning the production and pests and diseades susceptibility in Huambo country (Angola
Imaculada da Conceição Henriques
Full Text Available Os objectivos deste trabalho consistiram em avaliar o comportamento de cultivares regionais de milho - ‘Branco redondo’ e ‘SAM3’ - e importadas - ‘ZM423’, ‘ZM521’, ‘ZM523’, ‘ZM611’, ‘ZM621’ - quanto à sua sensibilidade a brocas do colmo e da espiga e à virose MSV (Maize Streak Virus. Os ensaios realizaram-se em três locais do Planalto Central de Angola na época seca e na das chuvas. Nas duas épocas e nos três locais, não se registaram infecções pelo vírus MSV nas cultivares regionais; todavia, nas importadas houve incidência da doença embora com baixa severidade. Em relação às brocas, não se observaram diferenças significativas entre as cultivares e a severidade foi baixa. A produção das cultivares importadas foi superior na época seca, com um rendimento entre as 7 e 8 t ha-1. Em sequeiro (época das chuvas as cultivares importadas produziram, em média, entre 3 a 4 t ha-1. As cultivares locais não mostraram uma variação tão acentuada no rendimento entre as duas épocas. Em geral, os valores médios do rendimento da ’Branco redondo’ e ‘SAM3’ foram de 2 t ha-1, com excepção desta última na Chianga, que atingiu as 4 t ha-1 em sequeiro. A supremacia da ‘SAM3’ na época chuvosa na Chianga deve-se certamente ao facto de ter sido aí seleccionada.The main objectives of this work were the evaluation of the behaviour of different traditional maize varieties - ‘Branco redondo’ and ‘SAM3’ - and imported ones - ‘ZM423’, ‘ZM521’, ‘ZM523’, ‘ZM611’, ‘ZM621’ - to their tolerance to the stem and earn borars and to the virus MSV (Maize Streak Virus, in three locations of the central highlands of Angola and in two cropping seasons (rainy and dry season. Maize yields were also evaluated. In the two growing seasons and in the three locations, the traditional varieties did not show any infection by the virus MSV. The imported varieties show disease symptoms but at a low
Le Clerc, V; Cadot, V; Canadas, M; Lallemand, J; Guèrin, D; Boulineau, F
The aim of this study, led by the GEVES (Research and Control Group for Varieties and Seeds), was to suggest indicators to assess the diversity available to farmers since the French Official Catalogue for Plant Varieties and Species was initiated. The largest datasets of 1990 inbred maize lines and 578 pea lines from the last 50 years were analysed using morphological and enzymatic parameters. Lines were grouped into three to five periods. Genetic diversity was estimated in each period from morphological and enzymatic markers by computing numerous indices, such as the number of classes of scores for each characteristic, allelic richness or genetic diversity index (H ( e )). Population differentiation parameters (G(ST), G(ST)', F(ST), Q(ST)) were also estimated between periods. While genetic diversity computed from distinction, uniformity, stability traits was more marked for maize (0.66) than for garden peas (0.35) or feed peas (0.29), the opposite trend was observed with enzymes, resulting in a genetic diversity of 0.43, 0.35 and 0.22 for garden peas, feed peas and maize, respectively. However, no significant changes in genetic diversity were observed over time, and genetic differentiation was slight between periods. All our results demonstrated that no significant reduction in the diversity available to farmers had been observed since initiation of the French Catalogue. The H ( e ) was a good indicator providing a quantitative estimate of genetic diversity, but it should be interpreted alongside a more precise indicator such as allelic richness or the number of classes for morphological characteristics.
Anand, Ajith; Bass, Steven H; Wu, Emily; Wang, Ning; McBride, Kevin E; Annaluru, Narayana; Miller, Michael; Hua, Mo; Jones, Todd J
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.
Fan, Lili; Fu, Kehe; Yu, Chuanjin; Li, Yingying; Li, Yaqian; Chen, Jie
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.
Tamiru, Amanuel; Bruce, Toby J A; Richter, Annett; Woodcock, Christine M; Midega, Charles A O; Degenhardt, Jörg; Kelemu, Segenet; Pickett, John A; Khan, Zeyaur R
Maize ( Zea mays ) emits volatile terpenes in response to insect feeding and egg deposition to defend itself against harmful pests. However, maize cultivars differ strongly in their ability to produce the defense signal. To further understand the agroecological role and underlying genetic mechanisms for variation in terpene emission among maize cultivars, we studied the production of an important signaling component ( E )-caryophyllene in a South American maize landrace Braz1006 possessing stemborer Chilo partellus egg inducible defense trait, in comparison with the European maize line Delprim and North American inbred line B73. The ( E) - caryophyllene production level and transcript abundance of TPS23, terpene synthase responsible for ( E) - caryophyllene formation, were compared between Braz1006, Delprim, and B73 after mimicked herbivory. Braz1006-TPS23 was heterologously expressed in E. coli , and amino acid sequences were determined. Furthermore, electrophysiological and behavioral responses of a key parasitic wasp Cotesia sesamiae to C . partellus egg-induced Braz1006 volatiles were determined using coupled gas chromatography electroantennography and olfactometer bioassay studies. After elicitor treatment, Braz1006 released eightfold higher ( E) -caryophyllene than Delprim, whereas no ( E) -caryophyllene was detected in B73. The superior (E)- caryophyllene production by Braz1006 was positively correlated with high transcript levels of TPS23 in the landrace compared to Delprim. TPS23 alleles from Braz1006 showed dissimilarities at different sequence positions with Delprim and B73 and encodes an active enzyme. Cotesia sesamiae was attracted to egg-induced volatiles from Braz1006 and synthetic (E)- caryophyllene. The variation in ( E) -caryophyllene emission between Braz1006 and Delprim is positively correlated with induced levels of TPS23 transcripts. The enhanced TPS23 activity and corresponding ( E) -caryophyllene production by the maize landrace could be
Marcelo J Carena
Full Text Available Maize has become a profitable alternative for North Dakota (ND farmers and ranchers. However, U.S. northern industry hybrids still lack cold and drought stress tolerance as well as adequate grain quality for ethanol and feedstock products. Moreover, there is a need to increase the value of feedstock operations before and after ethanol utilization. The ND maize breeding program initiated the development of hybrids with high quality protein content through the Early Quality Protein Maize for Feedstock (EarlyQPMF project. The North Dakota State University (NDSU maize breeding program acts as a genetic provider to foundation seed companies, retailer seed companies, processing industry, and breeders nationally and internationally. In the past 10 years, NDSU was awarded 9 PVP maize certificates and released 38 maize products. Within those, 13 inbred lines were exclusively released to a foundation seed company for commercial purposes. In addition, 2 hybrids were identified for commercial production in central and western ND.
Full Text Available Maize is the principal crop and major staple food in the most African and South American countries. The main problem in human nutrition in developing countries, and in livestock feed in developed countries, is insufficient production and poor quality of cereal proteins. In the case of maize, due to the very low content of essential amino acids lysine and tryptophan in grain endosperm, biological value is very low, which is main limiting factor of common maize in human nutrition and feeding of monogastric animals. Quality protein maize (QPM can help in solving of this problem. Maize production also faces serious constraints caused by agro-ecological conditions and poor socio-economic situation. To alleviate the effect of the constraints, selected genotypes with more desirable traits and appropriate field-plot techniques to create multiple-stress conditions, were used. It was found that, in downy mildew nursery distance up to 35 m from spreader plot is providing sufficient down load of spores for plant infection, provided that the testing breeding materials are planted towards to down-stream direction of the dominant wind. Using these breeding approaches large number of early, white and flint synthetics, composites and inbred lines were created with resistance or tolerance to downy mildew (DMR, maize streak virus (SR and drought (DT. Created genotypes exhibited very good kernel modification and yield potential under low and normal inputs. In the case of synthetics and composites, besides tolerance to multiple stress factors, they were competing in yield with local QPM and normal maize checks. In the case of created inbred lines high combining ability was exhibited both in non-conventional and conventional maize hybrids. Trial data revealed that in the most cases the best entries were over-yielding the best checks.
Full Text Available Identifying and characterizing alternative splicing (AS enables our understanding of the biological role of transcript isoform diversity. This study describes the use of publicly available RNA-Seq data to identify and characterize the global diversity of AS isoforms in maize using the inbred lines B73 and Mo17, and a related species, sorghum. Identification and characterization of AS within maize tissues revealed that genes expressed in seed exhibit the largest differential AS relative to other tissues examined. Additionally, differences in AS between the two genotypes B73 and Mo17 are greatest within genes expressed in seed. We demonstrate that changes in the level of alternatively spliced transcripts (intron retention and exon skipping do not solely reflect differences in total transcript abundance, and we present evidence that intron retention may act to fine-tune gene expression across seed development stages. Furthermore, we have identified temperature sensitive AS in maize and demonstrate that drought-induced changes in AS involve distinct sets of genes in reproductive and vegetative tissues. Examining our identified AS isoforms within B73 × Mo17 recombinant inbred lines (RILs identified splicing QTL (sQTL. The 43.3% of cis-sQTL regulated junctions are actually identified as alternatively spliced junctions in our analysis, while 10 Mb windows on each side of 48.2% of trans-sQTLs overlap with splicing related genes. Using sorghum as an out-group enabled direct examination of loss or conservation of AS between homeologous genes representing the two subgenomes of maize. We identify several instances where AS isoforms that are conserved between one maize homeolog and its sorghum ortholog are absent from the second maize homeolog, suggesting that these AS isoforms may have been lost after the maize whole genome duplication event. This comprehensive analysis provides new insights into the complexity of AS in maize.
Xia, Y L; Ding, J; Zhang, Z M; Rong, T Z; Shi, L Y; Pan, G T
18599Hong, a good Maize (Zea mays) inbred line as well as good transformation acceptor with high regeneration capacity, was used for isolating embryonic callus regeneration genes. Subtractive library was constructed by Suppression subtractive hybridization and screened by Reverse Northern Hybridization. The clones of No. 27 was randomly picked to sequence. NCBI blastx results showed the similarity to elongation factor 1gamma in rice.
Three potato (Solunum tuberosum) varieties and one maize variety were intercropped in six spatial arrangements, viz., sole crops, 2:1, 2:2, 1:1, 1:2 potato: maize row arrangements and one additive mixture. Intercropping influenced some growth parameters of potato but not of maize. For instance, the rate of potato stem ...
Howard, Julie A.; Chitala, George M.; Kalonge, Sylvester M.
Michigan State University (MSU) is currently assessing the impact of agricultural research on various commodities in seven African countries: Cameroon (maize, cowpea, sorghum), Kenya (maize, wheat), Malawi (maize), Mali (maize), Niger (sorghum, cowpea, millet), Uganda (oilseeds), and Zambia (maize). These countries were selected because they represent a variety of agro-ecological regions, and because their research systems have received significant levels of funding from USAID. The country st...
Dell'Acqua, Matteo; Gatti, Daniel M; Pea, Giorgio; Cattonaro, Federica; Coppens, Frederik; Magris, Gabriele; Hlaing, Aye L; Aung, Htay H; Nelissen, Hilde; Baute, Joke; Frascaroli, Elisabetta; Churchill, Gary A; Inzé, Dirk; Morgante, Michele; Pè, Mario Enrico
Maize (Zea mays) is a globally produced crop with broad genetic and phenotypic variation. New tools that improve our understanding of the genetic basis of quantitative traits are needed to guide predictive crop breeding. We have produced the first balanced multi-parental population in maize, a tool that provides high diversity and dense recombination events to allow routine quantitative trait loci (QTL) mapping in maize. We produced 1,636 MAGIC maize recombinant inbred lines derived from eight genetically diverse founder lines. The characterization of 529 MAGIC maize lines shows that the population is a balanced, evenly differentiated mosaic of the eight founders, with mapping power and resolution strengthened by high minor allele frequencies and a fast decay of linkage disequilibrium. We show how MAGIC maize may find strong candidate genes by incorporating genome sequencing and transcriptomics data. We discuss three QTL for grain yield and three for flowering time, reporting candidate genes. Power simulations show that subsets of MAGIC maize might achieve high-power and high-definition QTL mapping. We demonstrate MAGIC maize's value in identifying the genetic bases of complex traits of agronomic relevance. The design of MAGIC maize allows the accumulation of sequencing and transcriptomics layers to guide the identification of candidate genes for a number of maize traits at different developmental stages. The characterization of the full MAGIC maize population will lead to higher power and definition in QTL mapping, and lay the basis for improved understanding of maize phenotypes, heterosis included. MAGIC maize is available to researchers.
Orange maize in Zambia: crop development and delivery experience. ... African Journal of Food, Agriculture, Nutrition and Development ... of concept, that vitamin A maize varieties can be developed without compromising yield levels and that these varieties can deliver sufficient quantities of vitamin A to improve nutrition.
... 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 ...
Solanum tuberosum L.) on the incidence of potato aphids and leafhoppers was conducted at Namulonge in Uganda during the two growing seasons of 1995. Three potato varieties and one maize variety were intercropped in six spatial ...
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...
Achon, Maria Angeles; Alonso-Dueñas, Natalia
This study assesses the effect of Bt-maize on the distribution of maize viruses. Random surveys were conducted in Spain between 2001 and 2006 to evaluate the occurrence of maize viruses in Bt-maize cultivation areas and in areas where this crop had not been introduced. Maize dwarf mosaic virus (MDMV) was the predominant virus in Bt-areas, and Maize rough dwarf virus (MRDV) was the most predominant one in non-Bt-areas, with MRDV an emergent virus in both types of areas. A decline in the occurrence of MDMV and an increase in that of Sugarcane mosaic virus was observed in Bt-areas. Additionally, data obtained over 6 years in experimental fields showed non-significant differences between the infection rates exhibited by two generations of Bt varieties and the non-transformed isogenics varieties for any of the viruses. Our data suggest that differences in virus distribution are linked to the genetic background of the maize varieties and the distribution of virus reservoirs rather than to Bt-maize cultivation.
PERTUMBUHAN TANAMAN JAGUNG (Zea mays, L. VARIETAS BISI-2 PADA PASIR REJECT DAN PASIR ASLI DI PANTAI TRISIK KULONPROGO (The Growth of Maize Crop (Zea mays L. BISI-2 Variety on Rejected and non Rejected Sand at Pantai Trisik Kulon Progo
mineral is extracted, the remaining sand (reject sand will be returned as reclaimed material to be replanted. The aim of this study was to investigate the effect of different growth media called rejected and non rejected sand also fertilizer dossage of manure and NPK on the growth of maize crop (Zea mays L. BISI-2 variety at Pantai Trisik Kulon Progo. Fertilizers dossage that used in this study were 0 Kg manure and 0 g NPK (control, 0 Kg manure and 75 g NPK, 2,5 Kg manure and 0 g NPK, 2,5 Kg manure and 112,5 g NPK, 2,5 Kg manure and 75 g NPK, and 3,75 Kg manure and 37,5 g NPK. The parameters measured including plant height, number of leaves, dry weight of shoot, flowering time, number of cob, weight of cob, lenght of cob, and diameter of cob. The data collected were analyzed with Analysis of variance (Anova and for the advance test Duncan’s Multiple Range Test (DMRT was used. The results of this study showed that the avarage of plant height, number of leaves, dry weight of shoot, number of cob, weight of cob, lenght of cob, and diameter of cob of maize crop (Zea mays L. BISI-2 variety on reject sand was higher than non rejected sand but the average of flowering time of maize crop (Zea mays L. BISI-2 variety on rejected sand is longer than non rejected sand. In addition, the result of this study showed that the optimum vegetatif growth of maize crop was gained on dossage of 1,25 Kg manure and 112,5 g NPK but the most generatif growth of maize crop gained on dossage 3,75 Kg manure and 37,5 g NPK.
The green revolution in Asia was led by the semi dwarf varieties of wheat and rice during the 1960s. Nowadays ... Castor (Racinnus communis L.) is an industrial non edible oil seed that originated in East. Africa probably Ethiopia ... At the fourth generation single plants from each inbred line were reciprocally crossed to ...
Mohammad Hassan Rahimi
Full Text Available To identify drought tolerant lines among 168 recombinant inbred lines derived from a cross between Hindi variety of L3685 (high yielding, erect type and early growth as female parent and Iranian variety of Qazvin (with prostrate growth and late growth as male parent, two experiments were conducted in randomized complete block design with three replications under non-stress and drought stress conditions at the experimental Field of Shahrekord University in 2013. Results of combined analysis of variance showed that there were significant differences among lines under study in both experimental conditions in terms of grain yield (P≤0.01. Significant interaction of line×conditions revealed that lines responded differently to drought stress based on grain yield. Results also indicates that lines 160, 125 and 129 were promising lines under both conditions in terms of grain yield. Positive and significant correlation between tolerance indices and grain yield under stress and non-stress conditions indicated that the STI, MP, HARM and GMP indices may identify promising from non promising lines. Based on the above criteria, lines 160, 125, 48, 103 and 129 were recognized as drought tolerant lines. According to the results of principal components analysis, the first and second components determined 97.8% of the total variations among genotypes under study for drought resistance indices. The distribution of lines in the biplot showed genetic variations to the drought stress and thus lines 160, 125, 48, 129 and 103 were identified as high yielders under drought stress condition.
Dec 13, 2010 ... (L) Inbred line. Numbers from 10 to 21 refer to the four cultivars and eight inbred lines from US introduced in Mozambique in 2006. Table 2. Decamer arbritary primers used for DNA amplification. Primer. Nucleotide sequence (5' – 3'). Primer. Nucleotide sequence (5' – 3'). OPA-11. CAA TCG CCG T. OPF-16.
Lee, Hyeyoung; Zhang, Zhanyuan J
Agrobacterium tumefaciens-mediated transformation is one of the most efficient and simple gene delivery systems for genetic improvement and biology studies in maize. This system has become more widely used by both public and private laboratories. However, transformation efficiencies vary greatly from laboratory to laboratory for the same genotype. Here, we illustrate our advanced Agrobacterium-mediated transformation method in Hi-II maize using simple binary vectors. The protocol utilizes immature embryos as starting explants and the bar gene as a selectable marker coupled with bialaphos as a selective agent. The protocol offers efficient transformation results with high reproducibility, provided that some experimental conditions are well controlled. This transformation method, with minor modifications, can be also employed to transform certain maize inbreds.
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...
Zhang, J; Ku, L X; Han, Z P; Guo, S L; Liu, H J; Zhang, Z Z; Cao, L R; Cui, X J; Chen, Y H
Maize architecture is a major contributing factor to their high level of productivity. Maize varieties with an erect-leaf-angle (LA) phenotype, which increases light harvesting for photosynthesis and grain-filling, have elevated grain yields. Although a large body of information is available on the map positions of quantitative trait loci (QTL) for LA, little is known about the molecular mechanism of these QTL. In this study, the ZmCLA4 gene, which is responsible for the qLA4-1 QTL associated with LA, was identified and isolated by fine mapping and positional cloning. The ZmCLA4 gene is an orthologue of LAZY1 in rice and Arabidopsis. Sequence analysis revealed two SNPs and two indel sites in ZmCLA4 between the D132 and D132-NIL inbred maize lines. Association analysis showed that C/T/mutation667 and CA/indel965 were strongly associated with LA. Subcellular localization verified the functions of a predicted transmembrane domain and a nuclear localization signal in ZmCLA4. Transgenic maize plants with a down-regulated ZmCLA4 RNAi construct and transgenic rice plants over-expressing ZmCLA4 confirmed that the ZmCLA4 gene located in the qLA4 QTL regulated LA. The allelic variants of ZmCLA4 in the D132 and D132-NIL lines exhibited significant differences in leaf angle. ZmCLA4 transcript accumulation was higher in D132-NIL than in D132 during all the developmental stages and was negatively correlated with LA. The gravitropic response was increased and cell shape and number at the leaf and stem junctions were altered in D132-NIL relative to D132. These findings suggest that ZmCLA4 plays a negative role in the control of maize LA through the alteration of mRNA accumulation, leading to altered shoot gravitropism and cell development. The cloning of the gene responsible for the qLA4-1 QTL provides information on the molecular mechanisms of LA in maize and an opportunity for the improvement of plant architecture with regard to LA through maize breeding. © The Author 2014
Full Text Available Germplasm architecture refers to how favorable alleles for a given trait are distributed across the genome in a germplasm collection. Our objective was to assess germplasm architecture for quantitative traits among US maize ( L. inbreds. A total of 271 inbreds were genotyped at 28,626 single nucleotide polymorphism (SNP loci and phenotyped for anthesis date, plant height, starch and protein concentration, and resistance to northern corn leaf blight (NCLB, caused by . Chromosomal effects were calculated as the sum of the trait effects of SNP alleles carried on a specific chromosome by an inbred. The chromosomal effects were further decomposed into the mean effects of chromosomes, mean effects of inbreds, and chromosome × inbred effects. On average, none of the 10 maize chromosomes was particularly rich or poor in favorable quantitative trait locus (QTL alleles. However, extreme values of chromosome × inbred effects often involved chromosomes 5 and 8 for anthesis date, chromosomes 1 and 5 for plant height, and chromosome 9 for protein concentration. Inbreds with one or two chromosomes deficient in favorable alleles were candidates for improvement via chromosome-substitution lines. Specific chromosomes for which each of five genetic backgrounds (B73, Mo17, Oh43, A321, and PH207 were rich or poor for unknown favorable alleles were also identified. Chromosomal effects varied widely even when prior association mapping in the same germplasm collection had failed to identify any QTL. Genomewide marker effects, particularly when partitioned into chromosomal effects, provide a simple way to dissect germplasm architecture for quantitative traits.
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.
Full Text Available Six maize inbred lines for which we assumed that have a similar genetic background were selected for the study. Inbred lines were crossed according to incomplete diallel design and fifteen hybrid combinations were obtained. Hybrid combinations and their parental lines were used in our study. The objective of the study was to examine genetic polymorphism of parental lines, as well as to determine relationships between SSR genetic distance and values of high parent heterosis and specific combining abilities for grain yield. By using 19 SSR primers we classified inbred lines in two groups. First cluster consists of inbred lines L1, L2, L3, L4 and L5, while inbred line L6 formed second cluster, indicating different heterotic background in comparison to the other five inbred lines. The Spearman’s correlation coefficients between SSR based genetic distance and specific combining abilities for grain yield had a value of (r=0,53*, while positive correlation were also found between genetic distance and high parent heterosis (r=0,57*. [Projekat Ministarstva nauke Republike Srbije, br. TR31068
Supply of 2.00 ml of moisture seemed enough for optimum striga germination. Results from a glasshouse trial also showed significant effects of moisture on striga and maize agronomic characters, except for maize flag leaf length and grain yields. The maize varieties also differed significantly for striga syndrome rating, plant ...
Ahmad, M; Saleem, M; Ahsan, M; Ahmad, A
A set of sixty inbred lines of maize (Zea mays L.) were screened in the greenhouse at the seedling stage under both normal and water-deficit conditions. Six water deficit-tolerant inbred lines were selected based on root to shoot ratios. These selected lines were crossed in a diallel pattern. The parental, F1, and reciprocal cross plants were planted in a field under both normal and water-deficit conditions. Normal irrigation was applied to the control set, while the water-deficit set received 50% of normal irrigation levels. Analyses of variance of various morpho-physiological parameters identified significant differences among the selected lines under both conditions, indicating the presence of significant genetic variability. Variance components for general combining ability (GCA), specific combining ability (SCA), and reciprocal effects for all the parameters were estimated to determine the relative importance of additive and non-additive or dominance type of gene action. Variance components for GCA were larger than for SCA indicating the preponderance of additive types of gene action for all the traits under study. Hybrids developed from inbred lines W-10 and W-64SP proved to have the best grain yield under normal and water-deficit conditions. Under water-deficit conditions, the best performing cross was B-34 x W-10. Hence, these inbred lines and the hybrids might be of value in future breeding programs.
drawn maize- cum-fertilizer planter (RAP) was developed. The implement was compared ... land and seed sowing, RAP (14.29+2.36 hr.ha-1) had shown greater efficiency over SAP .... condition, most varieties of maize crop grow well in the area.
This study was therefore designed to determine the contribution of farmers\\' adoption of recommended maize production practices, namely maize varieties, seed spacing, fertilization and weeding on production efficiency in order to assess the soundness of the advice given to farmers. The research was conducted in the ...
Field experiments were conducted at the University of Ilorin Teaching and Research Farm in 2005 and 2006 cropping seasons with the objective to evaluate the combining ability for maize grain yield and other agronomic characters in 10 open pollinated maize varieties, which have been selected for high yield and stress ...
Maize (Zea mays L.) is an important staple food crop in Uganda and is emerging as a cash crop for smallholder farmers. Maize has, therefore, been prioritised by the Government of Uganda for continuous improvement through the national agricultural research system, resulting in the release of several improved varieties.
Full Text Available Abstract Background Ostrinia nubilalis (ECB and Sesamia nonagrioides (MCB are two maize stem borers which cause important losses in temperate maize production, but QTL analyses for corn borer resistance were mostly restricted to ECB resistance and maize materials genetically related (mapping populations derived from B73. Therefore, the objective of this work was to identify and characterize QTLs for MCB resistance and agronomic traits in a RILs population derived from European flint inbreds. Results Three QTLs were detected for stalk tunnel length at bins 1.02, 3.05 and 8.05 which explained 7.5% of the RILs genotypic variance. The QTL at bin 3.05 was co-located to a QTL related to plant height and grain humidity and the QTL at bin 8.05 was located near a QTL related to yield. Conclusions Our results, when compared with results from other authors, suggest the presence of genes involved in cell wall biosynthesis or fortification with effects on resistance to different corn borer species and digestibility for dairy cattle. Particularly, we proposed five candidate genes related to cell wall characteristics which could explain the QTL for stalk tunnelling in the region 3.05. However, the small proportion of genotypic variance explained by the QTLs suggest that there are also many other genes of small effect regulating MCB resistance and we conclude that MAS seems not promising for this trait. Two QTLs detected for stalk tunnelling overlap with QTLs for agronomic traits, indicating the presence of pleitropism or linkage between genes affecting resistance and agronomic traits.
Williams, W P; Windham, G L
A diallel cross of eight maize, Zea mays L., inbred lines was analyzed for reaction to two species of root-knot nematodes, Meloidogyne arenaria (Neal) Chitwood and M. javanica (Treub) Chitwood. Egg production following inoculation of F1 hybrid seedlings with nematode eggs was determined in a greenhouse experiment. Data were analyzed using Griffing's Method 4, Model I. General combining ability was a significant source of variation in egg production of both M. arenaria and M. javanica; specific combining ability was not a significant source of variation for either. The correlation between egg production of the two nematode species on the 28 F1 hybrids was highly significant. Hybrids with Mp313 or SC213 as one parent were the most resistant to both species. This indicates that germ plasm is available for developing inbred lines and hybrids with resistance to both M. arenaria race 2 and M. javanica.
Full Text Available Although much appreciated in Brazil, commercial popcorn is currently cropped on a fairly small scale. A number of problems need to be solved to increase production, notably the obtaintion of seeds with good agronomic traits and good culinary characteristics. With the objective of developing superior genotypes in popcorn, a second cycle of intrapopulation recurrent selection based on inbred S1 families was carried out. From the first cycle of selection over the UNB-2U population, 222 S1 families were obtained, which were then divided into six sets and evaluated in a randomized complete block design with two replications within the sets. Experiments were carried out in two Brazilian localities. The analysis of variance revealed environmental effects for all evaluated traits, except popping and stand, showing that, for most traits, these environments affected genotype behavior in different ways. In addition, the set as source of variation was significant for most of the evaluated traits, indicating that dividing the families into sets was an efficient strategy. Genotype-by-environment interaction was detected for most traits, except popping expansion and stand. Differences among genotypes were also detected (1% F-test, making viable the proposition of using the genetic variability in the popcorn population as a basis for future recurrent selection cycles. Superior families were selected using the Smith and Hazel classic index, with predicted genetic gains of 17.8% for popping expansion and 26.95% for yield.
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.
A survey of 126 maize farmers was conducted in northern Tanzania with the objective of examining adoption of cross-pollinated seeds among farmers who recycle improved seeds. In this study, an improved variety is defined as any variety that has been bred using formal plant breeding methods. Formally bred cultivars that ...
Full Text Available Teosinte (Zea mays ssp. parviglumis is the wild ancestor of modern maize (Zea mays ssp. mays. Teosinte contains greater genetic diversity compared with maize inbreds and landraces, but its use is limited by insufficient genetic resources to evaluate its value. A population of teosinte near isogenic lines (NILs was previously developed to broaden the resources for genetic diversity of maize, and to discover novel alleles for agronomic and domestication traits. The 961 teosinte NILs were developed by backcrossing 10 geographically diverse parviglumis accessions into the B73 (reference genome inbred background. The NILs were grown in two replications in 2009 and 2010 in Columbia, MO and Aurora, NY, respectively, and near infrared reflectance spectroscopy and nuclear magnetic resonance calibrations were developed and used to rapidly predict total kernel starch, protein, and oil content on a dry matter basis in bulk whole grains of teosinte NILs. Our joint-linkage quantitative trait locus (QTL mapping analysis identified two starch, three protein, and six oil QTL, which collectively explained 18, 23, and 45% of the total variation, respectively. A range of strong additive allelic effects for kernel starch, protein, and oil content were identified relative to the B73 allele. Our results support our hypothesis that teosinte harbors stronger alleles for kernel composition traits than maize, and that teosinte can be exploited for the improvement of kernel composition traits in modern maize germplasm.
Wu, Yongrui; Wang, Wenqin; Messing, Joachim
A balanced composition of amino acids in seed flour is critical because of the demand on essential amino acids for nutrition. However, seed proteins in cereals like maize, the crop with the highest yield, are low in lysine, tryptophan, and methionine. Although supplementation with legumes like soybean can compensate lysine deficiency, both crops are also relatively low in methionine. Therefore, understanding the mechanism of methionine accumulation in the seed could be a basis for breeding cultivars with superior nutritional quality. In maize (Zea mays), the 22- and 19-kDa α-zeins are the most prominent storage proteins, nearly devoid of lysine and methionine. Although silencing synthesis of these proteins through RNA interference (RNAi) raises lysine levels in the seed, it fails to do so for methionine. Computational analysis of annotated gene models suggests that about 57% of all proteins exhibit a lysine content of more than 4%, whereas the percentage of proteins with methionine above 4% is only around 8%. To compensate for this low representation, maize seeds produce specialized storage proteins, the 15-kDa β-, 18-kDa and 10-kDa δ-zeins, rich in methionine. However, they are expressed at variant levels in different inbred lines. A654, an inbred with null δ-zein alleles, methionine levels are significantly lower than when the two intact δ-zein alleles are introgressed. Further silencing of β-zein results in dramatic reduction in methionine levels, indicating that β- and δ-zeins are the main sink of methionine in maize seed. Overexpression of the 10-kDa δ-zein can increase the methionine level, but protein analysis by SDS-PAGE shows that the increased methionine levels occur at least in part at the expense of cysteines present in β- and γ-zeins. The reverse is true when β- and γ-zein expression is silenced through RNAi, then 10-kDa δ-zein accumulates to higher levels. Because methionine receives the sulfur moiety from cysteine, it appears that when
Full Text Available Abstract Background A balanced composition of amino acids in seed flour is critical because of the demand on essential amino acids for nutrition. However, seed proteins in cereals like maize, the crop with the highest yield, are low in lysine, tryptophan, and methionine. Although supplementation with legumes like soybean can compensate lysine deficiency, both crops are also relatively low in methionine. Therefore, understanding the mechanism of methionine accumulation in the seed could be a basis for breeding cultivars with superior nutritional quality. Results In maize (Zea mays, the 22- and 19-kDa α-zeins are the most prominent storage proteins, nearly devoid of lysine and methionine. Although silencing synthesis of these proteins through RNA interference (RNAi raises lysine levels in the seed, it fails to do so for methionine. Computational analysis of annotated gene models suggests that about 57% of all proteins exhibit a lysine content of more than 4%, whereas the percentage of proteins with methionine above 4% is only around 8%. To compensate for this low representation, maize seeds produce specialized storage proteins, the 15-kDa β-, 18-kDa and 10-kDa δ-zeins, rich in methionine. However, they are expressed at variant levels in different inbred lines. A654, an inbred with null δ-zein alleles, methionine levels are significantly lower than when the two intact δ-zein alleles are introgressed. Further silencing of β-zein results in dramatic reduction in methionine levels, indicating that β- and δ-zeins are the main sink of methionine in maize seed. Overexpression of the 10-kDa δ-zein can increase the methionine level, but protein analysis by SDS-PAGE shows that the increased methionine levels occur at least in part at the expense of cysteines present in β- and γ-zeins. The reverse is true when β- and γ-zein expression is silenced through RNAi, then 10-kDa δ-zein accumulates to higher levels. Conclusions Because methionine
Full Text Available Cycloxydim-Tolerant Maize (CTM was developed by researches at the University of Minnesota. CTM plants were regenerated from tissue culture selected for callus growth in the presence of cycloxydim, and the resulting plants were shown to contain a nuclear mutation, expressed as a single, partially dominant gene (known as Acc1 that conferred tolerance to the herbicide. Cycloxydim is a systemic herbicide for post emergence application in dicot crops to selectively control grass weeds. Corn, like most grasses is susceptible to cycloxydim due to inhibited acetyl-coenzyimeA carboxylaze enzyme activity. There are two key benefits of this technology: first, cycloxydim applications in CTM hybrids can be delayed until the weed spectrum and population density exceed agro-economic threshold; second, cycloxydim can be applied at either stage of plant development with no effect on basic agronomic traits, compared to non treated plants. Nevertheless, this type of tolerance requires 2 genes to be fully effective, i.e. gene must be present in both inbred parents to provide complete tolerance in the resulting hybrid. Such type of tolerance doubles the chances for yield drag and doubles the number of inbred conversions needed. This also limits germplasm integration and increases time lag in developing hybrids. Despite these difficulties, many seed companies introduce tolerance to cycloxydim into their commercial inbreds, and many of them have already commercialized CTM hybrids. Finally, it came as a logical question what is more important – hybrid performance or new trait? Critical to the success of this technology has been yield performance of CTM hybrids. At the same time, performance and herbicide tolerance do not exclude each other and can surely co-exist. To be accepted, this coexistence must secure high profitability to corn producers. However, CTM hybrids will not replace conventional ones on a large scale, but could be used as a specific tool, or could
García de Yzaguirre, Álvaro; Lasa Dolhagaray, José Manuel
[EN] With 40 to 50 different seed vigour tests available, appropiate procedures for choosing the best single test or combination the best predictors of seedling emergence of maize (Zea Mays L.) under severe conditions. Thirteen vigour tests and various field emergence trials were performed on six inbred lines and two commercial hybrids. The best single predictors of field emergence were identified by calculating simple correlation coefficients. The calculation of the geometric mean of the res...
ÜNAY*, Aydın; BASAL, Hüseyin; KONAK, Cahit
Inheritance of grain yield, heterosis and combining ability were investigated in maize populations obtained from half-diallel crossing among 9 inbred parental lines. General and specific combining ability effects were significantly different among parental lines. The grain yield was under the dominance gene effect. The parents W 552 and DNB were considered suitable according to their yield capacities and general combining ability effects. The midparent heterosis values ranged from 46.10% (H.9...
Harmon Frank G
Full Text Available Abstract Background The plant circadian clock orchestrates 24-hour rhythms in internal physiological processes to coordinate these activities with daily and seasonal changes in the environment. The circadian clock has a profound impact on many aspects of plant growth and development, including biomass accumulation and flowering time. Despite recent advances in understanding the circadian system of the model plant Arabidopsis thaliana, the contribution of the circadian oscillator to important agronomic traits in Zea mays and other cereals remains poorly defined. To address this deficit, this study investigated the transcriptional landscape of the maize circadian system. Results Since transcriptional regulation is a fundamental aspect of circadian systems, genes exhibiting circadian expression were identified in the sequenced maize inbred B73. Of the over 13,000 transcripts examined, approximately 10 percent displayed circadian expression patterns. The majority of cycling genes had peak expression at subjective dawn and dusk, similar to other plant circadian systems. The maize circadian clock organized co-regulation of genes participating in fundamental physiological processes, including photosynthesis, carbohydrate metabolism, cell wall biogenesis, and phytohormone biosynthesis pathways. Conclusions Circadian regulation of the maize genome was widespread and key genes in several major metabolic pathways had circadian expression waveforms. The maize circadian clock coordinated transcription to be coincident with oncoming day or night, which was consistent with the circadian oscillator acting to prepare the plant for these major recurring environmental changes. These findings highlighted the multiple processes in maize plants under circadian regulation and, as a result, provided insight into the important contribution this regulatory system makes to agronomic traits in maize and potentially other C4 plant species.
Full Text Available Kernel row number (KRN is an important component of yield during the domestication and improvement of maize and controlled by quantitative trait loci (QTL. Here, we fine-mapped a major KRN QTL, KRN4, which can enhance grain productivity by increasing KRN per ear. We found that a ~3-Kb intergenic region about 60 Kb downstream from the SBP-box gene Unbranched3 (UB3 was responsible for quantitative variation in KRN by regulating the level of UB3 expression. Within the 3-Kb region, the 1.2-Kb Presence-Absence variant was found to be strongly associated with quantitative variation in KRN in diverse maize inbred lines, and our results suggest that this 1.2-Kb transposon-containing insertion is likely responsible for increased KRN. A previously identified A/G SNP (S35, also known as Ser220Asn in UB3 was also found to be significantly associated with KRN in our association-mapping panel. Although no visible genetic effect of S35 alone could be detected in our linkage mapping population, it was found to genetically interact with the 1.2-Kb PAV to modulate KRN. The KRN4 was under strong selection during maize domestication and the favorable allele for the 1.2-Kb PAV and S35 has been significantly enriched in modern maize improvement process. The favorable haplotype (Hap1 of 1.2-Kb-PAV-S35 was selected during temperate maize improvement, but is still rare in tropical and subtropical maize germplasm. The dissection of the KRN4 locus improves our understanding of the genetic basis of quantitative variation in complex traits in maize.
Valquíria Sheila Zago
Full Text Available The objective of this study was to estimate the genetic parameters of the IPR 114 maize commercial variety for breeding purpose and the efficiency of the method. It was perfomed two cycles of half-sib progenie, between 2004 and 2007. The progenies were evaluated in a randomized complete block desing with two replications per environments and the plots were composed of one 4 m length row spaced on 0.8 m, and five plants per meter. The trials were carried out in Londrina and Ponta Grossa, Paraná State, Brazil. There were evaluated 173 and 154 progenies for selection cycles 1 and 2, respectively, analyzing the following traits: plant height, ear height, days to flower, prolificacy and predict grain yield. In both cycles verified significant genetic variability between progenies. Significant selection gains were obtained for predict grain yield, showing 6.33 and 5.03% for cycles 1 and 2, respectively. The estimative for genetic parameters obtained in this work justify the selection program continuity of the IPR 114 maize populationO objetivo deste trabalho foi obter estimativas de parâmetros genéticos, na variedade comercial IPR 114 para fins de melhoramento. Realizou-se dois ciclos de seleção recorrente entre e dentro de progênies de meios-irmãos no período de 2004 a 2007. As progênies foram avaliadas em delineamento de blocos casualizados, com duas repetições por local sendo a parcela útil uma linha de 4,0 m de comprimento e 0,8 m entre linhas deixando cinco plantas por metro. Os ensaios foram conduzidos em Londrina e Ponta Grossa, Estado do Paraná. Avaliaram-se 173 e 154 progênies, respectivamente, para os ciclos 1 e 2 de seleção, analisando-se as variáveis: altura de plantas e de espigas, florescimento feminino, prolificidade e peso de grãos. Nos dois ciclos de seleção verificou-se variabilidade genética significativa entre progênies. Para peso de grãos foram preditos ganhos de seleção significativos, sendo para o ciclo
Nereu Augusto Streck
Full Text Available The objective of this work was to simulate maize leaf development in climate change scenarios at Santa Maria, RS, Brazil, considering symmetric and asymmetric increases in air temperature. The model of Wang & Engel for leaf appearance rate (LAR, with genotype-specific coefficients for the maize variety BRS Missões, was used to simulate tip and expanded leaf accumulated number from emergence to flag leaf appearance and expansion, for nine emergence dates from August 15 to April 15. LAR model was run for each emergence date in 100-year climate scenarios: current climate, and +1, +2, +3, +4 and +5°C increase in mean air temperature, with symmetric and asymmetric increase in daily minimum and maximum air temperature. Maize crop failure due to frost decreased in elevated temperature scenarios, in the very early and very late emergence dates, indicating a lengthening in the maize growing season in warmer climates. The leaf development period in maize was shorter in elevated temperature scenarios, with greater shortening in asymmetric temperature increases, indicating that warmer nights accelerate vegetative development in maize.
Full Text Available In this study, seven maize inbred lines representing different tropical, drought tolerant populations and two adapted temperate maize inbred lines were crossed in a half-diallel mating design to determine combining abilities. The genotypes were tested in well-watered (WW and managed water stressed (WS conditions in 2013 and 2014. General combining ability (GCA and specific combining ability (SCA mean squares were significant for all investigated traits and demonstrated both additive and non-additive genetic effects in both conditions. Higher desired leaf rolling, leaf senescence, stomatal conductance and leaf chlorophyll content GCA effects of tropical inbreds under WS conditions showed the presence of the valuable allels related to drought stress. SCA analysis revealed that the best hybrids for water use efficiency and irrigation water use efficiency were tropical x temperate crosses. Stress tolerance index and drought resistance index identified G5 x G9, a tropical x temperate hybrid, as the most tolerant hybrid to drought. Our study suggests that tropical drought tolerant germplasm has the potential to contribute useful genetic diversity to temperate maize breeding programs.
Pechanova, Olga; Pechan, Tibor
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.
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.
Full Text Available Drought is a major abiotic stress factor limiting crop growth, development and production worldwide. The objective of this study was to evaluate tolerance to osmotic stress of maize seedlings. More than 6,000 accessions from the Maize Research Institute gene bank were tested under controlled drought (at flowering in Egypt, and afterwards in temperate climate (Serbia and Macedonia. Out of 41 drought tolerant accessions in the field, five inbred lines were chosen for laboratory testing, as well as one drought sensitive line. These genotypes were exposed to 4% polyethylene glycol-PEG (Mr 10000 for 24 h and 48 h. Nine-day-old seedlings compared to control conditions were analyzed in root and shoot length, fresh and dry weight and proline content. Results showed reduction in all parameters under stress, while only proline content increased in all PEG treated genotypes compared to control.
Studies were conducted in four locations in Ghana in 1986 to determine the effect of seven planting densities: 10, 20, 30, 40, 50, 60 and 70 x 103 plants/ha on grain yield of three maize varieties differing in maturity: early, medium and full season. Maize grain yield was significanlly influenced by leaf area index, variety and ...
Miller, Theresa A; Muslin, Elizabeth H; Dorweiler, Jane E
Maize (Zea mays ssp. mays L.) was domesticated from teosinte (Z. mays L. ssp. parviglumis Iltis & Doebley), a plant requiring short day photoperiods to flower. While photoperiod sensitive landraces of maize exist, post-domestication breeding included efforts to grow maize in a broad range of latitudes. Thus, modern maize is often characterized as day-neutral because time to flower is relatively unaffected by photoperiod. We report the first identification of maize constans of Zea mays1 (conz1), a gene with extensive sequence homology to photoperiod genes CONSTANS (CO) in Arabidopsis (Arabidopsis thaliana (L.) Heynh.) and Heading date1 (Hd1) in rice (Oryza sativa L.). conz1 maps to a syntenous chromosomal location relative to Hd1. Additionally, conz1 and two maize homologs of another photoperiod gene exhibit diurnal expression patterns notably similar to their Arabidopsis and rice homologs. The expression pattern of conz1 in long days is distinct from that observed in short days, suggesting that maize is able to discern variations in photoperiod and respond with differential expression of conz1. We offer models to reconcile the differential expression of conz1 with respect to the photoperiod insensitivity exhibited by temperate inbreds.
Meng, Qingfeng; Chen, Xinping; Lobell, David B; Cui, Zhenling; Zhang, Yi; Yang, Haishun; Zhang, Fusuo
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.
Gray leaf spot (Cercospora zeae-maydis), Turcicum leaf blight (Exserohilum turcicum) and common rust. (Puccinia sorghi) were scored on a scale of 1 (clean, no infestation) to 5 (severely diseased). Grain yield was recorded from all ears in the harvest area at harvest. Then grain yield (t ha-1) was calculated using average ...
All agronomic practices were carried out uniformly and simultaneously on the plots. In addition, structured questionnaires were administered to 20 members of each of the cooperative farms. Participants were selected by means of simple random sampling techniques to solicit information on the performance of SAMMAZ 17 ...
managed baby trial design. Mean grain yields ranged between ... crop in West and Central Africa (WCA), yet yields are low as a result of mainly low soil fertility ... geneous community (Snapp 2002). This on- farm research paradigm consists of a ...
Valéria Aparecida Vieira Queiroz
Full Text Available The aim of this study was to characterize the Zn and Fe availability by phytic acid/Zn and phytic acid/Fe molar ratios, in 22 tropical maize inbred lines with different genetic backgrounds. The Zn and Fe levels were determined by atomic absorption spectrophotometry and the P through colorimetry method. Three screening methods for phytic acid (Phy analysis were tested and one, based on the 2,2'-bipyridine reaction, was select. There was significant variability in the contents of zinc (17.5 to 42 mg.kg-1, iron (12.2 to 36.7 mg.kg-1, phosphorus (230 to 400 mg.100 g-1, phytic acid (484 to 1056 mg.100 g-1, phytic acid P (140 to 293 mg.100 g-1 and available-P (43.5 to 199.5 mg.100 g-1, and in the available-P/total-P ratio (0.14 to 0.50, Phy/Zn (18.0 to 43.5 and Phy/Fe (16.3 to 45.5 molar ratios. Lines 560977, 560978 and 560982 had greater availability of Zn and lines 560975, 560977, 561010 and 5610111 showed better Fe availability. Lines 560975, 560977 and 560978 also showed better available-P/total-P ratio. Thus, the lines 560975, 560977 and 560978 were considered to have the potential for the development of cultivars of maize with high availability of Fe and/or Zn.
Pollen is the primary means of gene flow between plants and plant populations and plays a critical role in seed production. Our overall objective is to better understand the molecular and genetic basis of the pollen function. We compared gene expression levels in seedlings, mat...
Jun 1, 2011 ... Genotype (G) by environment (E) interaction (G x E) was non-significant for stem borer leaf damage, number of exit ... Hybrid 5 x 9 was the best performing hybrid in grain yield (6.53 t/ha) across the locations, while hybrid 1 x 4 was the ... Developed from multiple insect resistant population 590. 8. P590 C7 ...
Gamma-irradiation and in-vitro culture, separately or combined, as a tool for inducing mutation in maize were evaluated. This type of research has been hampered in maize because (i) maize is a cross pollinating crop and highly heterozygous and (ii) embryogenesis and plant regeneration of plants from in-vitro culture have been difficult. In the present study, carefully designed and elaborated experiments were conducted using an inbred line CH1 31 which is capable of somatic embryogenesis for the subject of mutagenesis and another line Bu 8Ro 2 for the test cross partner. Results showed: 1) Both the regeneration of plants from in-vitro culture and gamma-irradiation induced a similar spectrum of morphological variation. Although the variation with somaclones was more frequent that radiation induced mutations under the conditions used, combination of explant irradiation and in-vitro culture gave the highest frequencies of genetic variation. 2) Some of the mutations in quantitative characters can be recogned in heterozygous state. 3) Mutation can cause variation in combining ability (extent of heterosis). 4) Efficiency at embryogenesis differs with genotypes of maize. 3 refs, 11 figs, 4 tabs
Starr, J L; Yang, W; Yan, Y; Crutcher, F; Kolomiets, M
Maize is a well-known host for Meloidogyne incognita, and there is substantial variation in host status among maize genotypes. In previous work it was observed that nematode reproduction increased in the moderately susceptible maize inbred line B73 when the ZmLOX3 gene from oxylipid metabolism was knocked out. Additionally, in this mutant line, use of a nonspecific primer for phenyl alanine ammonialyase (PAL) genes indicated that expression of these genes was reduced in the mutant maize plants whereas expression of several other defense related genes was increased. In this study, we used more specific gene primers to examine the expression of six PAL genes in three maize genotypes that were good, moderate, and poor hosts for M. incognita, respectively. Of the six PAL genes interrogated, two (ZmPAL3 and ZmPAL6) were not expressed in either M. incognita-infected or noninfected roots. Three genes (ZmPAL1, ZmPAL2, and ZmPAL5) were strongly expressed in all three maize lines, in both nematode-infected and noninfected roots, between 2 and 16 d after inoculation (DAI). In contrast, ZmPAL4 was most strongly expressed in the most-resistant maize line W438, was not detected in the most-susceptible maize line CML, and was detected only at 8 DAI in the maize line B73 that supported intermediate levels of reproduction by M. incognita. These observations are consistent with at least one PAL gene playing a role in modulating host status of maize toward M. incognita and suggest a need for additional research to further elucidate this association.
This final report summarizes the progress made towards the enhancement and distribution of genetic resources (e.g. genetic stocks, seed and DNA clones) used for basic and applied aspects of the genetic improvement of maize and sorghum. The genetic maps of maize and sorghum were improved through comparative mapping of RFLP loci detected by 124 maize cDNA clones and through the development of a new mapping population of maize. Comparative mapping between maize and sorghum and maize and rice, using the set of 124 maize cDNA clones (and other clones) in each study, substantiated previous observations of extensive conservation of locus order but it also provided strong evidence of numerous large-scale chromosomal rearrangements. The new mapping population for maize (intermated B73xMo17, 'IBM') was created by random intermating during the first segregating generation. Intermating for four generations prior to the derivation of recombinant inbred lines (RILs) increased the frequency of recombinants at many regions of the maize genome and provided better genetic resolution of locus order. Expansion of the maize genetic map was not uniform along the length of a linkage group and was less than the theoretical expectation. The 350 IBM RILs were genotyped at 512 loci detected by DNA clones, including 76 of the 124 supported by this contract. The production of the sorghum mapping population of RILs from the cross CK60xPI229828 has been delayed by weather conditions that were not conducive to plant growth and seed development. Seed of the IBM RILs have been distributed (approximately 5000 RILs in total) to 16 research organizations in the public and private sector. The DNA clones have been distributed (1,206 in total) to nine research labs. Further distribution of the seed and clones will be managed by curators at stock centers in the public domain. (author)
Henrique José Camargo Senhorinho
Full Text Available The objective of this study was to evaluate the combining ability and inbreeding depression of commercial maize hybrids for agricultural traits. Twenty-two commercial maize hybrids, 96 F1 crosses from a partial diallel scheme, 22 S1 populations and 4 controls were evaluated in a 12x12 simples square lattice experimental setup, totaling 144 treatments, in the municipality of Sabáudia (PR, Brazil, for harvests from 2011/2012 and 2012/2013. Three traits were evaluated: grain yield, plant height and ear height. The Griffing method (1956 was applied for the evaluation of the general combining ability (GCA and specific combining ability (SCA. The 30B39, 30K64 and 30B30 hybrids showed increased yield, 30F53 and P1630 showed reduced plant height and AG9040 and AG7010 showed reduced ear height. These hybrids can be recommended for the extraction of inbred lines and formation of composites followed by intrapopulation selection. The combinations 30B39 x AG8088, 30B39 x AG9045 and P1630 x AG8021 showed desirable SCA effects for grain yield, plant height and ear height and are recommended for use in reciprocal recurrent selection programs. High magnitudes of inbreeding depression were verified for yield and lower values for inbreeding depression for plant and ear heights. Thus, strategies are recommended for interpopulation breeding accompanied by inbred lines extraction.
Full Text Available Pb can damage the physiological function of human organs by entering the human body via food-chain enrichment. Revealing the mechanisms of maize tolerance to Pb is critical for preventing this. In this study, a Pb-tolerant maize inbred line, 178, was used to analyse transcription factors (TFs expressed under Pb stress based on RNA sequencing data. A total of 464 genes expressed in control check (CK or Pb treatment samples were annotated as TFs. Among them, 262 differentially expressed transcription factors (DETs were identified that responded to Pb treatment. Furthermore, the DETs were classified into 4 classes according to their expression patterns, and 17, 12 and 2 DETs were significantly annotated to plant hormone signal transduction, basal transcription factors and base excision repair, respectively. Seventeen DETs were found to participate in the plant hormone signal transduction pathway, where basic leucine zippers (bZIPs were the most significantly enriched TFs, with 12 members involved. We further obtained 5 Arabidopsis transfer DNA (T-DNA mutants for 6 of the maize bZIPs, among which the mutants atbzip20 and atbzip47, representing ZmbZIP54 and ZmbZIP107, showed obviously inhibited growth of roots and above-ground parts, compared with wild type. Five highly Pb-tolerant and 5 highly Pb-sensitive in maize lines were subjected to DNA polymorphism and expression level analysis of ZmbZIP54 and ZmbZIP107. The results suggested that differences in bZIPs expression partially accounted for the differences in Pb-tolerance among the maize lines. Our results contribute to the understanding of the molecular regulation mechanisms of TFs in maize under Pb stress.
Full Text Available Popcorn is different from other maize types with its popping ability. Popcorn has a special place in human nutrition of nutrient content, vitamins and minerals it contains. It is also a good diet product with the stomach acid absorption, reducing the feeling of hunger, giving the feeling of satiety and being low in calories as a whole grain. This study was carried out in Batı Akdeniz Agricultural Research Institute’s (BATEM Field Crops Department in 2014. The experiment was conducted as a randomized complete block design with three replications. Some quality traits of thirty five popcorn inbred lines were examined. In the research, kernel moisture value 14.97-17.63%, popping volume 8.3-29.3 cm3 g-1, rate of unpopped kernels 1.8-35.4%, kernel size 58.3-102.3 number 10 g -1, flavor test 1.4-3.6, gumminess 1.5-4.0 were found. As a result of the research 5, 6, 7, 10, 13, 16, 17, 24 and 26 lines came into prominence from the point of quality. When the relationships between quality traits were investigated, significant and positive correlations were determined between gumminess and flavor, popping volume and kernel size as well as flavor and grain moisture. Also, significant and negative correlations were determined between rate of unpopped kernels and popping volume, rate of unpopped kernels and kernel size, as well as popping volume and flavor.
In the early 1930s, J. B. S. Haldane and C. H. Waddington collaborated on the consequences of genetic linkage and inbreeding. One elegant mathematical genetics problem solved by them concerns recombinant inbred lines (RILs) produced via repeated self or brother–sister mating. In this classic contribution, Haldane ...
Santiago, Rogelio; Cao, Ana; Butrón, Ana
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. PMID:26308050
Rizwan, Muhammad; Ali, Shafaqat; Qayyum, Muhammad Farooq; Ok, Yong Sik; Zia-Ur-Rehman, Muhammad; Abbas, Zaheer; Hannan, Fakhir
Maize (Zea mays L.) has been widely adopted for phytomanagement of cadmium (Cd)-contaminated soils due to its high biomass production and Cd accumulation capacity. This paper reviewed the toxic effects of Cd and its management by maize plants. Maize could tolerate a certain level of Cd in soil while higher Cd stress can decrease seed germination, mineral nutrition, photosynthesis and growth/yields. Toxicity response of maize to Cd varies with cultivar/varieties, growth medium and stress duration/extent. Exogenous application of organic and inorganic amendments has been used for enhancing Cd tolerance of maize. The selection of Cd-tolerant maize cultivar, crop rotation, soil type, and exogenous application of microbes is a representative agronomic practice to enhance Cd tolerance in maize. Proper selection of cultivar and agronomic practices combined with amendments might be successful for the remediation of Cd-contaminated soils with maize. However, there might be the risk of food chain contamination by maize grains obtained from the Cd-contaminated soils. Thus, maize cultivation could be an option for the management of low- and medium-grade Cd-contaminated soils if grain yield is required. On the other hand, maize can be grown on Cd-polluted soils only if biomass is required for energy production purposes. Long-term field trials are required, including risks and benefit analysis for various management strategies aiming Cd phytomanagement with maize.
Abul Kalam Azad Mohammad
Full Text Available In rabi season 2012, six diversed maize inbred lines were crossed in all possible combinations without reciprocals by using a half diallel mating design to obtain 15 single cross. Inbred parents and their F1 single crosses with a check were evaluated in rabi season 2013 to evaluate the role of general and specific combining ability and heterosis for some quantitative traits. Significant general combining ability variances was observed only for cob height and specific combining ability variances were observed for plant height, cob height, cob length, cob girth, number of kernels per cob, cob weight and hundred grain weight. The GCA/SCA ratio was less than unity for all studied traits except shelling percentage; this means that these traits are pre-dominantly controlled by non-additive gene action. Based on GCA estimates, it could be concluded that the best combiners were ML01, ML05 and ML29 inbred lines for most of the studied traits. This result indicated that these inbred lines could be considered as good combiners for improving these traits. Significant positive SCA effects were found for all studied traits except number of kernels per row and shelling percentage. Based on SCA effects, it could be concluded that the crosses ML01×ML02, ML02×ML05, ML02×ML29 and ML05×ML15 could be exploited by the maize breeders to increase maize yield. Three F1 hybrids such as ML02×ML15, ML02×ML29 and ML05×ML15 proved to be the outstanding hybrids to immediate further steps for commercial cultivation. In a conclusive decision the F1 hybrid, ML02×ML29 was the best combination as evaluated through combining ability and standard heterosis.
Williams, W P; Buckley, P M; Davis, F M
The fall armyworm, Spodoptera frugiperda (J. E. Smith), and southwestern corn borer, Diatraea grandiosella Dyar, are major insect pests of maize, Zea mays L., in the southern USA. Both insects feed extensively on leaves of plants in the whorl stage of growth. A diallel cross of seven inbred lines with different levels of susceptibility to leaf feeding damage in the field was evaluated in a laboratory bioassay for fall armyworm and southwestern corn borer larval growth. Diets were prepared from lyophilized leaf tissue of field-grown plants of the inbred lines and their 21 F1 hybrids. One inbred line, Tx601, exhibited heavy leaf damage in field tests but showed moderate resistance in the laboratory bioassay. Both general and specific combining ability were highly significant sources of variation in the inheritance of fall armyworm and south-western corn borer larval growth in the laboratory bioassay. Tx601 showed excellent general combining ability for reduced larval growth of both species.
Guan, Ya-jing; Hu, Jin; Wang, Xian-ju; Shao, Chen-xia
Low temperature stress during germination and early seedling growth is an important constraint of global production of maize. The effects of seed priming with 0.25%, 0.50%, and 0.75% (w/v) chitosan solutions at 15 °C on the growth and physiological changes were investigated using two maize (Zea mays L.) inbred lines, HuangC (chilling-tolerant) and Mo17 (chilling-sensitive). While seed priming with chitosan had no significant effect on germination percentage under low temperature stress, it en...
Tzin, Vered; Fernandez-Pozo, Noe; Richter, Annett; Schmelz, Eric A.; Schoettner, Matthias; Schäfer, Martin; Ahern, Kevin R.; Meihls, Lisa N.; Kaur, Harleen; Huffaker, Alisa; Mori, Naoki; Degenhardt, Joerg; Mueller, Lukas A.; Jander, Georg
As a response to insect attack, maize (Zea mays) has inducible defenses that involve large changes in gene expression and metabolism. Piercing/sucking insects such as corn leaf aphid (Rhopalosiphum maidis) cause direct damage by acquiring phloem nutrients as well as indirect damage through the transmission of plant viruses. To elucidate the metabolic processes and gene expression changes involved in maize responses to aphid attack, leaves of inbred line B73 were infested with corn leaf aphids for 2 to 96 h. Analysis of infested maize leaves showed two distinct response phases, with the most significant transcriptional and metabolic changes occurring in the first few hours after the initiation of aphid feeding. After 4 d, both gene expression and metabolite profiles of aphid-infested maize reverted to being more similar to those of control plants. Although there was a predominant effect of salicylic acid regulation, gene expression changes also indicated prolonged induction of oxylipins, although not necessarily jasmonic acid, in aphid-infested maize. The role of specific metabolic pathways was confirmed using Dissociator transposon insertions in maize inbred line W22. Mutations in three benzoxazinoid biosynthesis genes, Bx1, Bx2, and Bx6, increased aphid reproduction. In contrast, progeny production was greatly decreased by a transposon insertion in the single W22 homolog of the previously uncharacterized B73 terpene synthases TPS2 and TPS3. Together, these results show that maize leaves shift to implementation of physical and chemical defenses within hours after the initiation of aphid feeding and that the production of specific metabolites can have major effects in maize-aphid interactions. PMID:26378100
Tzin, Vered; Fernandez-Pozo, Noe; Richter, Annett; Schmelz, Eric A; Schoettner, Matthias; Schäfer, Martin; Ahern, Kevin R; Meihls, Lisa N; Kaur, Harleen; Huffaker, Alisa; Mori, Naoki; Degenhardt, Joerg; Mueller, Lukas A; Jander, Georg
As a response to insect attack, maize (Zea mays) has inducible defenses that involve large changes in gene expression and metabolism. Piercing/sucking insects such as corn leaf aphid (Rhopalosiphum maidis) cause direct damage by acquiring phloem nutrients as well as indirect damage through the transmission of plant viruses. To elucidate the metabolic processes and gene expression changes involved in maize responses to aphid attack, leaves of inbred line B73 were infested with corn leaf aphids for 2 to 96 h. Analysis of infested maize leaves showed two distinct response phases, with the most significant transcriptional and metabolic changes occurring in the first few hours after the initiation of aphid feeding. After 4 d, both gene expression and metabolite profiles of aphid-infested maize reverted to being more similar to those of control plants. Although there was a predominant effect of salicylic acid regulation, gene expression changes also indicated prolonged induction of oxylipins, although not necessarily jasmonic acid, in aphid-infested maize. The role of specific metabolic pathways was confirmed using Dissociator transposon insertions in maize inbred line W22. Mutations in three benzoxazinoid biosynthesis genes, Bx1, Bx2, and Bx6, increased aphid reproduction. In contrast, progeny production was greatly decreased by a transposon insertion in the single W22 homolog of the previously uncharacterized B73 terpene synthases TPS2 and TPS3. Together, these results show that maize leaves shift to implementation of physical and chemical defenses within hours after the initiation of aphid feeding and that the production of specific metabolites can have major effects in maize-aphid interactions. © 2015 American Society of Plant Biologists. All Rights Reserved.
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% ...
Walaa Kamel Mousa
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.
Opaque -2 maize gave significantly better nett protein utilisation (NPU) values than normal maize varieties in trials performed with rats and chickens. .... MPF-8. YM-T2Ll. MPF-IO- T2L2. MPF-lO. MPF-5. YM. 74,59 (a)*. 70,62 (ab). 68,69 (abc). 68,63 (abed). 66,98 (bcde). 64,67 (bcdef). 64,26 (bcdef). 63,79 (cdef). 62,02 (ef).
Oct 4, 2007 ... The number of weeds per 1 m x 1 m guardant significantly varied among intercropping ... ability of soybean varieties in weed management under ..... Ababa, Ethiopia. pp. 124-131. Singh JN, Negi PS, Tripathi SK (1973). Study on the intercropping of soybean with maize and jower. India J. Agron. 18: 75-78.
Water absorption and proximate composition of four varieties of maize; sweet corn, pop corn, white corn and yellow corn soaked at different temperatures and time duration were determined. Absorption increased with increase in temperatures and time but generally low at 45°C. The total average rate of hydration at different ...
Dec 19, 2011 ... Wheat breeders in Pakistan relied upon phenotypic traits as indices of genetic variation among different wheat varieties which may ... expected area under wheat cultivation in Pakistan for the year 2010-2011 is 9.045 million ha .... Development of high genetic density maps of wheat, tobacco, maize, rice has.
The field experiment was carried out at Haro Sabu Agriculture Research Center, during 2013 with the objectives of determining the effect of varieties and population densities of soybean intercropped with maize on yield and yield components of associated crops and productivity of the system. The experiment was laid out in ...
commodity call for a relatively cheaper alternative to fertilizer application, so as to increase crop production while at the same time improving the fertility of the soil. In view of the above, this research was undertaken in other to study the yield performance of some cowpea varieties and maize under sole and intercropping.
quality protein maize (Zea mays L.) hybrid to plant density and nitrogen (N) fertilizer. The experiments were conducted at ... study, application of 90 kg N/ha to hybrid maize would give economic yield response and acceptable returns at low risk to farmers, ...... Nitrogen fertility on water stress and yield of winter wheat. Agron.
Nov 24, 2015 ... 4Department of Crop Science and Production, Sokoine University of Agriculture, P. O. Box 3005,. Chuo Kikuu ..... TABLE 2. Model calibration information extracted from crop variety experimental data, for the maize varieties used in Southern. Tanzania ... ranging from -2 to 5 °C, with an increment of 0.25.
Wang, Rong; Yang, Xinxin; Wang, Nian; Liu, Xuedong; Nelson, Richard S; Li, Weimin; Fan, Zaifeng; Zhou, Tao
Maize is a major crop whose rich genetic diversity provides an advanced resource for genetic research. However, a tool for rapid transient gene function analysis in maize that may be utilized in most maize cultivars has been lacking, resulting in reliance on time-consuming stable transformation and mutation studies to obtain answers. We developed an efficient virus-induced gene silencing (VIGS) vector for maize based on a naturally maize-infecting cucumber mosaic virus (CMV) strain, ZMBJ-CMV. An infectious clone of ZMBJ-CMV was constructed, and a vascular puncture inoculation method utilizing Agrobacterium was optimized to improve its utility for CMV infection of maize. ZMBJ-CMV was then modified to function as a VIGS vector. The ZMBJ-CMV vector induced mild to moderate symptoms in many maize lines, making it useful for gene function studies in critically important maize cultivars, such as the sequenced reference inbred line B73. Using this CMV VIGS system, expression of two endogenous genes, ZmPDS and ZmIspH, was found to be decreased by 75% and 78%, respectively, compared with non-silenced tissue. Inserts with lengths of 100-300 bp produced the most complete transcriptional and visual silencing phenotypes. Moreover, genes related to autophagy, ZmATG3 and ZmATG8a, were also silenced, and it was found that they function in leaf starch degradation. These results indicate that our ZMBJ-CMV VIGS vector provides a tool for rapid and efficient gene function studies in maize. © 2016 The Authors The Plant Journal © 2016 John Wiley & Sons Ltd.
Richardson, Jon; Smiseth, Per T
A recent theoretical model suggests that intraspecific competition is an important determinant of the severity of inbreeding depression. The reason for this is that intraspecific competition is density dependent, leading to a stronger negative effect on inbred individuals if they are weaker competitors than outbred ones. In support of this prediction, previous empirical work shows that inbred individuals are weaker competitors than outbred ones and that intraspecific competition often exacerbates inbreeding depression. Here, we report an experiment on the burying beetle Nicrophorus vespilloides, in which we recorded the outcome of competition over a small vertebrate carcass between an inbred or outbred male resident caring for a brood and a size-matched inbred or outbred male intruder. We found that inbred males were more successful as intruders in taking over a carcass from a male resident and were injured more frequently as either residents or intruders. Furthermore, inbred males gained less mass during the breeding attempt and had a shorter adult life span than outbred males. Finally, successful resident males reared a substantially smaller brood comprised of lighter larvae when the intruder was inbred than when it was outbred. Our results shows that inbred males increased their competitive effort, thus contradicting previous work suggesting that inbred males are weaker competitors. Furthermore, our results shows that inbred intruders impose a greater cost to resident males, suggesting that outbred individuals can suffer fitness costs as a result of competition with inbred ones.
Full Text Available The origin and evolution of maize has been attracting attention of researchers of different profiles for decades. Although a few researchers in our country have explicitly been dealing with these issues, it is necessary to survey studies within this field. Not only because of educational reasons, but also because revealing secrets on the origin and evolution provides knowledge about maize genome, which can influence the improvement of current breeding of this very important crop. The enhancement of genetic variability of commercial material is another crucial challenge faced by maize breeders. Therefore, a segment of this study is a reminder indicating that collected and described landraces conserved in the genebank of the Maize Research Institute 'Zemun Polje' are germplasm valuable to breeding programmes intended for moderate climate. Some inbred lines (ZPPE25-10-1; NS796; R70Ž; NS568 developed in our scientific institutions using adapted landraces were of a great commercial importance for maize breeding programmes. However, little has been done on the improvement of landraces. Consequently, it is our opinion that some breeding efforts should be aimed at this topic in order to provide further progress in the maize breeding improvement.
Shi, Liyu; Weng, Jianfeng; Liu, Changlin; Song, Xinyuan; Miao, Hongqin; Hao, Zhuanfang; Xie, Chuanxiao; Li, Mingshun; Zhang, Degui; Bai, Li; Pan, Guangtang; Li, Xinhai; Zhang, Shihuang
Maize rough dwarf disease (MRDD, a viral disease) results in significant grain yield losses, while genetic basis of which is largely unknown. Based on comparative genomics, eukaryotic translation initiation factor 4E (eIF4E) was considered as a candidate gene for MRDD resistance, validation of which will help to understand the possible genetic mechanism of this disease. ZmeIF4E (orthologs of eIF4E gene in maize) encodes a protein of 218 amino acids, harboring five exons and no variation in the cDNA sequence is identified between the resistant inbred line, X178 and susceptible one, Ye478. ZmeIF4E expression was different in the two lines plants treated with three plant hormones, ethylene, salicylic acid, and jasmonates at V3 developmental stage, suggesting that ZmeIF4E is more likely to be involved in the regulation of defense gene expression and induction of local and systemic resistance. Moreover, four cis-acting elements related to plant defense responses, including DOFCOREZM, EECCRCAH1, GT1GAMSCAM4, and GT1CONSENSUS were detected in ZmeIF4E promoter for harboring sequence variation in the two lines. Association analysis with 163 inbred lines revealed that one SNP in EECCRCAH1 is significantly associated with CSI of MRDD in two environments, which explained 3.33 and 9.04 % of phenotypic variation, respectively. Meanwhile, one SNP in GT-1 motif was found to affect MRDD resistance only in one of the two environments, which explained 5.17 % of phenotypic variation. Collectively, regulatory motifs respectively harboring the two significant SNPs in ZmeIF4E promoter could be involved in the defense process of maize after viral infection. These results contribute to understand maize defense mechanisms against maize rough dwarf virus.
José C. Jiménez-Galindo
Full Text Available Introduction: The Mediterranean corn borer (MCB, Sesamia nonagrioides, is a major pest of maize, Zea mays, in Mediterranean countries, inflicting significant kernel yield losses. For that reason, it necessary to know the genetic mechanisms that regulate the agronomic and resistance traits. A quantitative trait loci (QTL mapping study for yield, resistance against MCB attack, and other relevant agronomic traits was performed using a recombinant inbred line (RIL population derived from the cross A637 × A509 that is expected to segregate for yield, and ear, and stalk resistance to MCB. 171 RILs were evaluated in 2014 and 2015 at Pontevedra, Spain, along with the two parental inbreds A637 and A509 using a 13 × 14 single lattice design with two replications. A genetic map with 285 SNP markers was used for QTL analysis. Our objectives were to detect QTL for resistance to MCB and tolerance-related agronomic traits, to gain insights on the genetic relationship between resistance to MCB attack and yield, and to establish the best way for simultaneously improving yield and resistance to MCB.Results: Twelve significant QTL were detected for agronomic and resistance traits. QTL at bins 1.10 and 5.04 were especially interesting because the same allelic variant at these QTL simultaneously improved yield and insect resistance. In contrast, in the region 8.04–8.05, QTL showed opposite effects for yield and resistance. Several QTL for indexes which combine yield and resistance traits were found especially in the region 10.02–10.03.Conclusions: Selecting genotypes with the favorable allele of QTL on chromosome 5 (bin 5.01 will decrease tunnel length without affect yield, silking and plant height and QTL on the region 5.04 could be used to improve stalk resistance and yield simultaneously. An allele of QTL on bin 9.07 will increase ear resistance to MCB attack but it could produce later varieties while favorable allele in region 1.10 could improve ear and
Made J. Mejaya
Full Text Available Selection for increased oil level in maize showed the increase was associated with decrease in starch concentration, kernel weight, and grain yield. The study was conducted with the objectives: (1 to evaluate response to six cycles for increased grain yield in the high oil maize Alexho Elite (AE: 60-90 g kg-1 oil concentration and Ultra High Oil (UHO: 100-140 g kg-1 oil concentration using inbred tester B73; (2 to measure responses to selection for increased grain yield with changes in yield components; and (3 to determine a suitable tester. Previously the two synthetics had been selected for oil concentration. After six cycles, the six genotypes i.e. AE C0, AE C3, AE C6, UHO C0, UHO C3, and UHO C6 were testcrossed to B73, LH185, and LH202 inbreds (40 g kg-1 oil concentration to a total of 18 testcrosses. Two field experiments were used to evaluate selection in AE and UHO testcrosses. The study showed selection using inbred tester B73 in AE and UHO was effective in increasing grain yield of AE testcrosses without changing (i.e. decreasing oil and protein concentrations. AE testcrosses produced higher grain yield and greater selection response for grain yield than UHO testcrosses. LH185 was best for grain yield in AE and UHO testcrosses. Increase in grain yield in most of the testcrosses was associated with increases in starch concentration, kernel weight, kernel number, and grain weight.
Full Text Available Deleterious alleles have long been proposed to play an important role in patterning phenotypic variation and are central to commonly held ideas explaining the hybrid vigor observed in the offspring of a cross between two inbred parents. We test these ideas using evolutionary measures of sequence conservation to ask whether incorporating information about putatively deleterious alleles can inform genomic selection (GS models and improve phenotypic prediction. We measured a number of agronomic traits in both the inbred parents and hybrids of an elite maize partial diallel population and re-sequenced the parents of the population. Inbred elite maize lines vary for more than 350,000 putatively deleterious sites, but show a lower burden of such sites than a comparable set of traditional landraces. Our modeling reveals widespread evidence for incomplete dominance at these loci, and supports theoretical models that more damaging variants are usually more recessive. We identify haplotype blocks using an identity-by-decent (IBD analysis and perform genomic prediction analyses in which we weigh blocks on the basis of complementation for segregating putatively deleterious variants. Cross-validation results show that incorporating sequence conservation in genomic selection improves prediction accuracy for grain yield and other fitness-related traits as well as heterosis for those traits. Our results provide empirical support for an important role for incomplete dominance of deleterious alleles in explaining heterosis and demonstrate the utility of incorporating functional annotation in phenotypic prediction and plant breeding.
Yang, Jinliang; Mezmouk, Sofiane; Baumgarten, Andy; Buckler, Edward S; Guill, Katherine E; McMullen, Michael D; Mumm, Rita H; Ross-Ibarra, Jeffrey
Deleterious alleles have long been proposed to play an important role in patterning phenotypic variation and are central to commonly held ideas explaining the hybrid vigor observed in the offspring of a cross between two inbred parents. We test these ideas using evolutionary measures of sequence conservation to ask whether incorporating information about putatively deleterious alleles can inform genomic selection (GS) models and improve phenotypic prediction. We measured a number of agronomic traits in both the inbred parents and hybrids of an elite maize partial diallel population and re-sequenced the parents of the population. Inbred elite maize lines vary for more than 350,000 putatively deleterious sites, but show a lower burden of such sites than a comparable set of traditional landraces. Our modeling reveals widespread evidence for incomplete dominance at these loci, and supports theoretical models that more damaging variants are usually more recessive. We identify haplotype blocks using an identity-by-decent (IBD) analysis and perform genomic prediction analyses in which we weigh blocks on the basis of complementation for segregating putatively deleterious variants. Cross-validation results show that incorporating sequence conservation in genomic selection improves prediction accuracy for grain yield and other fitness-related traits as well as heterosis for those traits. Our results provide empirical support for an important role for incomplete dominance of deleterious alleles in explaining heterosis and demonstrate the utility of incorporating functional annotation in phenotypic prediction and plant breeding.
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.
Kuneš, Jaroslav; Dobešová, Zdenka; Musilová, Alena; Zídek, Václav; Vorlíček, Jaroslav; Pravenec, Michal; Křen, Vladimír; Zicha, Josef
Roč. 31, č. 8 (2008), s. 1659-1668 ISSN 0916-9636 R&D Projects: GA MŠk(CZ) 1M0510; GA ČR(CZ) GA305/08/0139; GA AV ČR(CZ) IAA500110604 Institutional research plan: CEZ:AV0Z50110509 Keywords : recombinant inbred strains * blood pressure * telemetry Subject RIV: ED - Physiology Impact factor: 3.146, year: 2008
Gowda, Manje; Das, Biswanath; Makumbi, Dan; Babu, Raman; Semagn, Kassa; Mahuku, George; Olsen, Michael S; Bright, Jumbo M; Beyene, Yoseph; Prasanna, Boddupalli M
Genome-wide association analysis in tropical and subtropical maize germplasm revealed that MLND resistance is influenced by multiple genomic regions with small to medium effects. The maize lethal necrosis disease (MLND) caused by synergistic interaction of Maize chlorotic mottle virus and Sugarcane mosaic virus, and has emerged as a serious threat to maize production in eastern Africa since 2011. Our objective was to gain insights into the genetic architecture underlying the resistance to MLND by genome-wide association study (GWAS) and genomic selection. We used two association mapping (AM) panels comprising a total of 615 diverse tropical/subtropical maize inbred lines. All the lines were evaluated against MLND under artificial inoculation. Both the panels were genotyped using genotyping-by-sequencing. Phenotypic variation for MLND resistance was significant and heritability was moderately high in both the panels. Few promising lines with high resistance to MLND were identified to be used as potential donors. GWAS revealed 24 SNPs that were significantly associated (P < 3 × 10(-5)) with MLND resistance. These SNPs are located within or adjacent to 20 putative candidate genes that are associated with plant disease resistance. Ridge regression best linear unbiased prediction with five-fold cross-validation revealed higher prediction accuracy for IMAS-AM panel (0.56) over DTMA-AM (0.36) panel. The prediction accuracy for both within and across panels is promising; inclusion of MLND resistance associated SNPs into the prediction model further improved the accuracy. Overall, the study revealed that resistance to MLND is controlled by multiple loci with small to medium effects and the SNPs identified by GWAS can be used as potential candidates in MLND resistance breeding program.
Computation of the intercrop efficiency revealed that maize and Black Dessie variety complemented each other under intercropping simultaneously and four weeks after maize emergence, indicating that they were not competing for exactly the same ecological niches. Generally, the agronomic measurements and ...
designed and fabricated to give a new model of the sheller. Comparative evaluation of shelling units of these two models was done using Longe-5 maize variety. Commercial maize farmers, extension agents and local political leaders were involved in the evaluation. The machine parameters evaluated were output in kg/hr/lt ...
Nov 30, 2011 ... Cry1Ab protein, neutral detergent fiber, acid detergent fiber, acid detergent lignin and crude protein. Silage from two of the Bt maize varieties had ... Mechanical disruption of cell walls and membranes during ... study was to determine the effects of ensiling Bt maize on concentration of the Cry1Ab protein and ...
Most countries in sub-Saharan Africa (SSA) grow open pollinated maize varieties (OPVs) because seed of maize OPVs can be recycled for several seasons with minimal yield reduction due to inbreeding as compared to hybrids. However, OPVs are heterogeneous, and some local seed suppliers attempt to take ...
Field trials were carried out at Umudike South eastern Agro-ecological zone of Nigeria, in the 2002 and 2003 cropping seasons to evaluate the effectiveness of stemborer resistant maize varieties, AMA–TZBR-WCI, TZBR--ELD3 and FARO 23 + FURADAN in protecting maize (Zea mays L) against stem borer infestation.
Stewart, L R; Teplier, R; Todd, J C; Jones, M W; Cassone, B J; Wijeratne, S; Wijeratne, A; Redinbaugh, M G
The two major U.S. maize viruses, Maize dwarf mosaic virus (MDMV) and Maize chlorotic dwarf virus (MCDV), emerged in southern Ohio and surrounding regions in the 1960s and caused significant losses. Planting resistant varieties and changing cultural practices has dramatically reduced virus impact in subsequent decades. Current information on the distribution, diversity, and impact of known and potential U.S. maize disease-causing viruses is lacking. To assess the current reservoir of viruses present at the sites of past disease emergence, we used a combination of serological testing and next-generation RNA sequencing approaches. Here, we report enzyme-linked immunosorbent assay and RNA-Seq data from samples collected over 2 years to assess the presence of viruses in cultivated maize and an important weedy reservoir, Johnsongrass (Sorghum halepense). Results revealed a persistent reservoir of MDMV and two strains of MCDV in Ohio Johnsongrass. We identified sequences of several other grass-infecting viruses and confirmed the presence of Wheat mosaic virus in Ohio maize. Together, these results provide important data for managing virus disease in field corn and sweet corn maize crops, and identifying potential future virus threats.
Mejía-Guerra, María Katherine; Li, Wei; Galeano, Narmer F; Vidal, Mabel; Gray, John; Doseff, Andrea I; Grotewold, Erich
Core promoters are crucial for gene regulation, providing blueprints for the assembly of transcriptional machinery at transcription start sites (TSSs). Empirically, TSSs define the coordinates of core promoters and other regulatory sequences. Thus, experimental TSS identification provides an essential step in the characterization of promoters and their features. Here, we describe the application of CAGE (cap analysis of gene expression) to identify genome-wide TSSs used in root and shoot tissues of two maize (Zea mays) inbred lines (B73 and Mo17). Our studies indicate that most TSS clusters are sharp in maize, similar to mice, but distinct from Arabidopsis thaliana, Drosophila melanogaster, or zebra fish, in which a majority of genes have broad-shaped TSS clusters. We established that ∼38% of maize promoters are characterized by a broader TATA-motif consensus, and this motif is significantly enriched in genes with sharp TSSs. A noteworthy plasticity in TSS usage between tissues and inbreds was uncovered, with ∼1500 genes showing significantly different dominant TSSs, sometimes affecting protein sequence by providing alternate translation initiation codons. We experimentally characterized instances in which this differential TSS utilization results in protein isoforms with additional domains or targeted to distinct subcellular compartments. These results provide important insights into TSS selection and gene expression in an agronomically important crop. © 2015 American Society of Plant Biologists. All rights reserved.
Full Text Available Corn (Zea mays L. crop that is grown on large areas - over 140 million hectares worldwide, and 400-500 thousand ha in Moldova due to production potential broad diversity of use as food for humans, animals, birds raw material for industrial processing. The upward trend in average yields achieved is largely attributed to the improvement of scientific programs. Select the line with the characters and traits that are transmitted hereditary hybrids and contribute to their performance, ensure progress in improvement. Therefore, the process of creating inbred lines associated with combining ability testing as a measure of productivity conferred hybrids, is significant research programs. Orientation purpose of improved maize hybrids to formulas and simple change to a superior capitalization heterosis effect and perfect uniformity of plant requires changes in methodology for the creation, evaluation and classification of inbred lines.
José Marcelo Soriano Viana
Full Text Available The development of hybrids is the most important objective in a corn breeding program. The objectives of thisstudy were to select and assess inbred lines, and to discuss the efficiency of four cycles of among and within inbred familyselection. Two experiments were evaluated, one with 144 S5 progenies of the popcorn population Beija-Flor and another withseven inbred lines. Based on expected gains in expansion volume, the best selective procedure was mass selection. The 14selected inbred lines should be divergent, because only two pairs were derived from the same S3 or S4 family. The analysis ofselection efficiency demonstrated that it is important to select superior plants in families with poorer performance to minimizethe loss of superior genotypes. The quality of the evaluated inbred lines was comparable to commercial populations and theyield satisfactory. The information about genealogy did not increase the inbred line selection efficiency.
Chen, Qiuyue; Liu, Zhipeng; Wang, Baobao; Wang, Xufeng; Lai, Jinsheng; Tian, Feng
Global transcriptome analysis in maize revealed differential nitrogen response between genotypes and implicate a crucial role of transcription factors in driving genotype by nitrogen interactions at gene expression level. Developing nitrogen-efficient cultivars are essential for sustainable and productive agriculture. Nitrogen use efficiency of plants is highly dependent on the interaction of environmental and genetic variation and results in adaptive phenotypes. This study used transcriptome sequencing to perform a comprehensive genotype by nitrogen (G × N) interaction analysis for two elite Chinese maize inbreds grown at normal and low nitrogen levels in field conditions. We demonstrated that the two maize inbreds showed contrasting agronomic and transcriptomic responses to changes in nitrogen availability. A total of 96 genes with a significant G × N interaction were detected. After characterizing the expression patterns of G × N interaction genes, we found that the G × N interaction genes tended to show condition-specific differential expression. The functional annotations of G × N interaction genes revealed that many different kinds of genes were involved in G × N interactions, but a significant enrichment for transcription factors was detected, particularly the AP2/EREBP and WRKY family, suggesting that transcription factors might play important roles in driving G × N interaction at gene expression level for nitrogen response in maize. Taken together, these results not only provide novel insights into the mechanism of nitrogen response in maize and set important basis for further characterization but also have important implications for other genotype by stress interaction.
Lawrence, Carolyn J.; Dong, Qunfeng; Polacco, Mary L.; Seigfried, Trent E.; Brendel, Volker
The Maize Genetics and Genomics Database (MaizeGDB) is a central repository for maize sequence, stock, phenotype, genotypic and karyotypic variation, and chromosomal mapping data. In addition, MaizeGDB provides contact information for over 2400 maize cooperative researchers, facilitating interactions between members of the rapidly expanding maize community. MaizeGDB represents the synthesis of all data available previously from ZmDB and from MaizeDB—databases that have been superseded by Maiz...
Butts-Wilmsmeyer, Carrie J; Mumm, Rita H; Bohn, Martin O
Although previous studies have examined the concentration of various nutritional compounds in maize, little focus has been devoted to the study of commercial maize hybrids or their inbred parents. In this study, a genetically and phenotypically diverse set of maize hybrids and inbreds relevant to U.S. commercial maize germplasm was evaluated for its variability in phytochemical content. Total protein, unsaturated fatty acids, tocopherols, soluble phenolics, and insoluble-bound phenolics were evaluated in this study. Of these compounds, only soluble and insoluble-bound phenolic acids exhibited means and variances that were at least as large as the means and variances reported for other sets of germplasm. This suggests that selection for high phenolic acid content is possible in current U.S. commercial germplasm. In contrast, while the total protein, unsaturated fatty acid, or tocopherol content could possibly be improved using current U.S. commercial germplasm, the results of this study indicate that the incorporation of more diverse sources of germplasm would most likely result in quicker genetic gains.
Tanumihardjo, Sherry A; Ball, Anna-Marie; Kaliwile, Chisela; Pixley, Kevin V
The enhancement of sweet potato and maize with provitamin A carotenoids has been part of HarvestPlus's research continuum since the formation of the biofortification project. This review includes case studies of biofortification strategies used for sweet potato in Uganda and orange maize in Zambia. The current status of the science and release of biofortified varieties was reviewed by three scientists who were part of the HarvestPlus program for more than a decade with input from a scientist who experienced orange maize dissemination in Zambia. High β-carotene varieties of sweet potato were introduced into South Africa and Mozambique, and efficacy and effectiveness studies, respectively, showed promise to improve vitamin A status, followed by dissemination efforts in Uganda. A randomized, controlled effectiveness trial tested extension models to promote sweet potato and assessed vitamin A intake among Ugandans. Orange maize breeding was initially a challenge, but considering that the carotenoid biosynthetic pathway was present in maize germplasm, breeders quickly bred higher amounts of provitamin A into the maize that was ultimately released in Zambia. Initial resistance occurred because orange maize was associated with yellow maize, which had negative connotations associated with food aid and animal feed, and consumers preferred white maize. Currently, both orange crops are available on the market. © 2017 New York Academy of Sciences.
Belmore, Nancy Fargo
"Variety" is defined as a "unique configuration of linguistic features." These features characterize the language of conversation, unscripted commentary, religion, newspaper reporting, and legal documents. Everyone learns many varieties of at least one language. The ambiguity of usage labels like "slang" and "colloquial" indicates that we know…
Speyer, D.; Jensen, Anders Nedergaard; Bogart, T.
The tropical variety of a d-dimensional prime ideal in a polynomial ring with complex coefficients is a pure d-dimensional polyhedral fan. This fan is shown to be connected in codimension one. We present algorithmic tools for computing the tropical variety, and we discuss our implementation...
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.
Chen, Liang; Cong, Yuanyuan; He, Hongxia; Yu, Ying
A novel transformation system was established for maize using Agrobacterium infection of in vitro cultured ovules. The maize ovules were isolated 24h after pollination and infected with Agrobacterium. The embryos were isolated from the pollinated ovules 2-3 weeks after Agrobacterium infection, regenerated to plantlets and investigated for transgene expression and inheritance. Experimental evaluations were focused on the four main aspects. Firstly, through the introduction of gus gene for monitoring transformation and development of embryo, it was confirmed that transgenic plants can be generated from in vitro cultured maize ovules infected with Agrobacterium. Secondly, in order to standardize the transformation protocol, several important factors that affected transformation efficiency were optimized. They included Agrobacterium delivery approach, surfactant, AS concentration, and cocultivation duration. Thirdly, stable expression and Mendelian inheritance of the introduced genes were analyzed in independent lines over two generations. Fourthly, the pollinated ovule culture-regeneration potential and transformation efficiency of five maize inbred lines were investigated to confirm the genotype independence of this transformation system. We conclude that the transformation system established in this study can be used to generate high-quality transgenic maize plants rapidly and directly. Copyright © 2013 Elsevier B.V. All rights reserved.
Elsanhoty, Rafaat M; Al-Turki, A I; Ramadan, Mohamed Fawzy
Qualitative and quantitative DNA-based methods were applied to detect genetically modified foods in samples from markets in the Kingdom of Saudi Arabia. Two hundred samples were collected from Al-Qassim, Riyadh, and Mahdina in 2009 and 2010. GMOScreen 35S and NOS test kits for the detection of genetically modified organism varieties in samples were used. The positive results obtained from GMOScreen 35S and NOS were identified using specific primer pairs. The results indicated that all rice samples gave negative results for the presence of 35S and NOS terminator. About 26 % of samples containing soybean were positive for 35S and NOS terminator and 44 % of samples containing maize were positive for the presence of 35S and/or NOS terminator. The results showed that 20.4 % of samples was positive for maize line Bt176, 8.8 % was positive for maize line Bt11, 8.8 % was positive for maize line T25, 5.9 % was positive for maize line MON 810, and 5.9 % was positive for StarLink maize. Twelve samples were shown to contain genetically modified (GM) soy and 6 samples >10 % of GM soy. Four samples containing GM maize were shown to contain >5 % of GM maize MON 810. Four samples containing GM maize were shown to contain >1 % of StarLink maize. Establishing strong regulations and certified laboratories to monitor GM foods or crops in Saudi market is recommended.
Krishna Prasad Timsina
maize varieties that can contribute to the feed security issues as well.
Full Text Available Previously, we found that the genotype of 42 out of 198 mouse microsatellite loci, which are distributed among all chromosomes except the Y chromosome, changed from monomorphism to polymorphism (CMP in a genetically modified inbred mouse strain. In this study, we further examined whether CMP also relates to the homologous recombination in gene knockout (KO mouse strains. The same 42 microsatellite loci were analyzed by polymerase chain reaction (PCR in 29 KO inbred mouse strains via short tandem sequence repeat (STR scanning and direct sequence cloning to justify microsatellite polymorphisms. The C57BL/6J and 129 mouse strains, from which these 29 KO mice were derived, were chosen as the background controls. The results indicated that 10 out of 42 (23.8% loci showed CMP in some of these mouse strains. Except for the trinucleotide repeat locus of D3Mit22, which had microsatellite CMP in strain number 9, the core sequences of the remaining 41 loci were dinucleotide repeats, and 9 out of 41 (21.95% showed CMPs among detected mouse strains. However, 11 out of 29 (37.9% KO mice strains were recognized as having CMPs. The popular dinucleotide motifs in CMP were (TG(n (50%, 2/4, followed by (GT(n (27.27%, 3/11 and (CA(n (23.08%, 3/13. The microsatellite CMP in (CT(n and (AG(n repeats were 20% (1/5. According to cloning sequencing results, 6 KO mouse strains showed insertions of nucleotides whereas 1 showed a deletion. Furthermore, 2 loci (D13Mit3 and D14Mit102 revealed CMP in 2 strains, and mouse strain number 9 showed CMPs in two loci (D3Mit22 and D13Mit3 simultaneously. Collectively, these results indicated that microsatellite polymorphisms were present in the examined inbred KO mice.
Petolino, J F; Thompson, S A
Response frequencies in maize (Zea mays L.) anthers cultured in vitro were examined in a diallel set of crosses among four commercial inbred lines. Significant differences among the genotypes were observed, with the crosses H99xFR16 and Pa91xFR16 displaying the highest responses. General (GCA) and specific (SCA) combining ability mean squares were calculated and determined to be highly significant. GCA effects among the parental lines were highest for FR16 and lowest for LH38. Nongenotypic, plant-toplant differences were also found to make a significant contribution to the overall variation observed. The results from this study indicate that parents which give rise to highly responsive hybrids can be identified and that genetic improvement is possible through selection.
EARO). 2001. Strategy Document for. Fruits. Addis Ababa, Ethiopia. Registration of Avocado (Persea americana Mill.) Varieties Hass, Fuerte, Pinkerton,. Bacon, Ettinger, and Nabal. Avocado is evergreen, medium to large sized fruit tree with ...
Motto, M; Saccomani, M; Cacco, G
Plant root nutrient uptake efficiency may be expressed by the kinetic parameters, Vmax and Km, as well as by normal enzymatic reactions. These parameters are apparently useful indices of the level of adaptation of genotypes to the nutrient conditions in the soil. Moreover, sulfate uptake capacity has been considered a valuable index for selecting superior hybrid characterized by both high grain yield and efficiency in nutrient uptake. Therefore, the purpose of this research was to determine combining ability for sulfate uptake, in a diallel series of maize hybrids among five inbreds. Wide differences among the 20 single crosses were obtained for Vmax and Km. The general and specific combining ability mean squares were significant and important for each trait, indicating the presence of considerable amount of both additive and nonadditive gene effects in the control of sulfate uptake. In addition, maternal and nonmaternal components of F1 reciprocal variation showed sizeable effects on all the traits considered. A relatively high correlation was also detected between Vmax and Km. However, both traits displayed enough variation to suggest that simultaneous improvement of both Vmax and Km should be feasible. A further noteworthy finding in this study was the identification of one inbred line, which was the best overall parent for improving both affinity and velocity strategies of sulfate uptake.
the control hybrids Turda 201, Turda Favorit and PR39D81. Variance analysis was performed according to the classical model of a two-factor system. Genic effects were calculated after 2nd North Carolina model. Regarding the results, the highest percentage of unbroken plants was on TD 268 tester (80.7% and the lowest on TD 364 tested line (70.2%. Tested lines that was noted for the general combining ability of lodging resistance were TA 452 and TE 335. Crossings that marked high values for non-additive effects were TA 452 x TC 385A, TE 202B x TC 399 and TE 202B x TD 268. Effects values for general combining ability were between -4.72% and +4.49% on tested lines, -1.68% and +5.78% on testers; effects values for specific combining ability were between -11.25% and +7.58%. Regarding the tested lines was noted TA 452 inbred line and regarding the testers was noted TD 268 inbred line. On this issue, we can state that in the selection process of maize hybrids must be chosen only those hybrid combinations with stalk-lodging resistance because of the similar contribution of additive and non-additive genic effects to resistant genotypes.
Full Text Available Maize (Zea mays, L. yield is strongly influenced by external nitrogen inputs and their availability in the soil solution. Overuse of nitrogen-fertilizers can have detrimental ecological consequences through increased nitrogen pollution of water and the release of the potent greenhouse gas, nitrous oxide. To improve yield and overall nitrogen use efficiency (NUE, a deeper understanding of nitrogen uptake and utilization is required. This study examines the performance of two contrasting maize inbred lines, B73 and F44. F44 was selected in Florida on predominantly sandy acidic soils subject to nitrate leaching while B73 was selected in Iowa on rich mollisol soils. Transcriptional, enzymatic and nitrogen transport analytical tools were used to identify differences in their N absorption and utilization capabilities. Our results show that B73 and F44 differ significantly in their genetic, enzymatic, and biochemical root nitrogen transport and assimilatory pathways. The phenotypes show a strong genetic relationship linked to nitrogen form, where B73 showed a greater capacity for ammonium transport and assimilation whereas F44 preferred nitrate. The contrasting phenotypes are typified by differences in root system architecture (RSA developed in the presence of both nitrate and ammonium. F44 crown roots were longer, had a higher surface area and volume with a greater lateral root number and density than B73. In contrast, B73 roots (primary, seminal, and crown were more abundant but lacked the defining features of the F44 crown roots. An F1 hybrid between B73 and F44 mirrored the B73 nitrogen specificity and root architecture phenotypes, indicating complete dominance of the B73 inbred. This study highlights the important link between RSA and nitrogen management and why both variables need to be tested together when defining NUE improvements in any selection program.
N Zafar Naderi
Full Text Available To evaluateresponse of bread wheat recombinant inbred lines to water deficit, a split plot experiment arranged in randomized complete block design (CRBD was conducted using eight recombinant inbred lines and their parental cultivars (Roshan and Super Head with three replications under three irrigation levels (80, 120 and 160 mm evaporation from class A pan at the Agriculture Research Station of Islamic Azad University, Tabriz Branch during 2009. The results of analysis of variance data collected revealed significant difference among lines and irrigation levels for grain yield. While line × irrigation level interaction was non significant for grain yield. Based on SSI and TOL, drought tolerance indices lines number 1, 7, 41 and Roshan cultivar under 120 mm evaporation, and lines number 7 and 19 under 160 mm evaporation were the tolerant lines. Under both stress conditions according to STI, MP and GMP indices, lines number 37, 38 and Roshan cultivar were recognized as the tolerant lines to water deficiet. Cluster analyses based on grain yield and drought tolerance indices recognized the lines number 1, 30, 32, 37, 38, 41 and Roshan cultivar under 120 mm and lines number 30, 37 and 38 and Roshan under 160 mm evaporation as the most drought tolerants and higher producers.
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.
Patrick T West
Full Text Available DNA methylation and dimethylation of lysine 9 of histone H3 (H3K9me2 are two chromatin modifications that can be associated with gene expression or recombination rate. The maize genome provides a complex landscape of interspersed genes and transposons. The genome-wide distribution of DNA methylation and H3K9me2 were investigated in seedling tissue for the maize inbred B73 and compared to patterns of these modifications observed in Arabidopsis thaliana. Most maize transposons are highly enriched for DNA methylation in CG and CHG contexts and for H3K9me2. In contrast to findings in Arabidopsis, maize CHH levels in transposons are generally low but some sub-families of transposons are enriched for CHH methylation and these families exhibit low levels of H3K9me2. The profile of modifications over genes reveals that DNA methylation and H3K9me2 is quite low near the beginning and end of genes. Although elevated CG and CHG methylation are found within gene bodies, CHH and H3K9me2 remain low. Maize has much higher levels of CHG methylation within gene bodies than observed in Arabidopsis and this is partially attributable to the presence of transposons within introns for some maize genes. These transposons are associated with high levels of CHG methylation and H3K9me2 but do not appear to prevent transcriptional elongation. Although the general trend is for a strong depletion of H3K9me2 and CHG near the transcription start site there are some putative genes that have high levels of these chromatin modifications. This study provides a clear view of the relationship between DNA methylation and H3K9me2 in the maize genome and how the distribution of these modifications is shaped by the interplay of genes and transposons.
Inbred strains generated from native and exotic pigs were compared with their F1 and F2 backcross populations for a range of litter performance traits. Animals were intensively reared and at 81/2 months of age, the inbred genotypes from each strain were reciprocally mated to each other to generate F1 crossbred genotypes ...
Louis, Joe; Basu, Saumik; Varsani, Suresh; Castano-Duque, Lina; Jiang, Victoria; Williams, W. Paul; Felton, Gary W.; Luthe, Dawn S.
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
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...
Peternell, Thomas; Schneider, Michael; Schreyer, Frank-Olaf
The Bayreuth meeting on "Complex Algebraic Varieties" focussed on the classification of algebraic varieties and topics such as vector bundles, Hodge theory and hermitian differential geometry. Most of the articles in this volume are closely related to talks given at the conference: all are original, fully refereed research articles. CONTENTS: A. Beauville: Annulation du H(1) pour les fibres en droites plats.- M. Beltrametti, A.J. Sommese, J.A. Wisniewski: Results on varieties with many lines and their applications to adjunction theory.- G. Bohnhorst, H. Spindler: The stability of certain vector bundles on P(n) .- F. Catanese, F. Tovena: Vector bundles, linear systems and extensions of (1).- O. Debarre: Vers uns stratification de l'espace des modules des varietes abeliennes principalement polarisees.- J.P. Demailly: Singular hermitian metrics on positive line bundles.- T. Fujita: On adjoint bundles of ample vector bundles.- Y. Kawamata: Moderate degenerations of algebraic surfaces.- U. Persson: Genus two fibra...
Jun 3, 2009 ... can be introgressed into other promising lines in developing early maturing and high yielding varieties for cultivation in the Nigeria savannas. Key words: Zea mays L., general combining ability, specific combining ability, grain yield, Nigeria savannas. INTRODUCTION. Maize production in the southern ...
Five new generations of maize streak virus (MSV) resistant varieties were evaluated along with two checks in replicated trials and for two years in a Southern Guinea Savanna Ecology of Nigeria, which is an endemic zone for the disease. Difference in grain yield between favourable growing season in 2002 and ...
Nov 2, 2016 ... (Chen et al., 2012) and quinoa (Bazile et al., 2014). This study aims at assessing the variability and genetic structure of local varieties of Ivorian maize using microsatellite markers. The results of the assessment can contribute to the ex situ conservation and the development of selection strategies in order to ...
With the continued development and release of such hybrids, there is need to continue to screen them in order to ascertain their potential productivity in different agro-ecologies. A study was, therefore, carried out between June and October 2011, to screen nine hybrid varieties of maize for growth and yield potentials in two ...
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 ...
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.
Five new generations of maize streak virus (MSV) resistant varieties were evaluated along with two checks in replicated trials and for two years in a southern guinea savanna ecology of Nigeria, which is an endemic zone for the disease. Difference in grain yield between favourable growing season in 2002 and unfavourable ...
Heerwaarden, van J.; Hellin, J.; Visser, R.G.F.; Eeuwijk, van F.A.
Replacement of crop landraces by modern varieties is thought to cause diversity loss. We studied genetic erosion in maize within a model system; modernized smallholder agriculture in southern Mexico. The local seed supply was described through interviews and in situ seed collection. In spite of the
The cultivation of transgenic glyphosate-resistant crop varieties can simplify weed control in crops such as maize and others. On the other hand, the repeated use of broadly effective herbicides like glyphosate, especially in the same crop, can have a negative effect on biodiversity. Additionally there is a risk for a spread of more tolerant or even resistant weed species.
study of protein, tryptophan and lysine composition of quality protein maize varieties (9). The tryptophan content of eleven superior QPM genotypes was much higher than those of wheat,. * Jimma University, College of Agriculture and Veterinary Medicine, Department of Crop Sciences, P.O. Box 307,. Jimma , Ethiopia.
Bernklau, E J; Hibbard, B E; Bjostad, L B
SUM2162 is the first known example of a naturally occurring maize, Zea mays L., genotype with antixenosis (nonpreference) resistance to western corn rootworm, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), larval feeding. Behavioral responses of neonate western corn rootworm larvae were evaluated in laboratory bioassays with seven maize genotypes selected for native resistance to rootworm feeding damage. Two susceptible maize genotypes and one transgenic (Bacillus thuringiensis) maize genotype were included as controls. In soil bioassays with cut roots, no larvae entered the roots of the resistant variety SUM2162, but at least 75% of the larvae entered the roots of every other maize type. Larvae made significantly fewer feeding holes in the roots of SUM2162 than in all the other maize genotypes, except the isoline control. In feeding bioassays, larval feeding varied significantly among maize genotypes, but there was no significant difference between the resistant varieties and the susceptible controls. There were no significant differences among any of the genotypes in host recognition (search) behavior of larvae after exposure to the roots. Little variation in feeding stimulant blends was observed among maize genotypes, indicating minimal contribution to the observed antixenosis.
Determining the genes responsible for pest resistance in maize can allow breeders to develop varieties with lower losses and less contamination with undesirable toxins. A gene sequence coding for a geranyl geranyl transferase-like protein located in a fungal ear rot resistance quantitative trait loc...
Neri, I; Frassetto, A; Pasquinelli, G; Patrizi, A
A case of a 25 year old man with the black variety of trichomicosis pubis is presented on account of its extreme rareity. Scanning electron microscopy confirms that trichomicosis pubis is caused by bacterial colonisation of the pubic hair and shows that bacteria are able to penetrate cuticular horny cells directly through their free plasma membrane.
Srdić Jelena; Nikolić Ana; Pajić Zorica
Sweet corn differs from field corn in many important traits. So its breeding although includes some standard procedures demand application of techniques that are important for determining special traits, all because of the specificity of its usage. Application of molecular markers becomes almost a necessity for the breeding of sweet corn, especially because this is the type of maize in which still no definitive heterotic patterns have been determined. So getting to know genetic divergence of ...
Chaikam, Vijay; Nair, Sudha K; Babu, Raman; Martinez, Leocadio; Tejomurtula, Jyothsna; Boddupalli, Prasanna M
R1-nj anthocyanin marker inhibition is highly frequent in tropical maize germplasm considerably affecting efficiency of haploid identification. Molecular markers reliably differentiating germplasm with anthocyanin color inhibitor have been identified in this study. The R1-Navajo (R1-nj) color marker facilitates easy and quick identification of haploid kernels at the seed stage during in vivo haploid induction process in maize. However, the Navajo phenotype can be completely suppressed or poorly expressed in some germplasm, making it impossible or inefficient to identify haploids at the seed stage. In this study, we characterized the expression of R1-nj marker in a large array of tropical/subtropical inbred lines, breeding populations and landraces by crossing with the R1-nj-based tropicalized haploid inducer. There was a high frequency of inhibition of the Navajo phenotype in the maize inbred lines, which are used in tropical breeding programs. Genome-wide association mapping showed that the C1 anthocyanin regulatory locus is the most significant genetic factor influencing inhibition of the Navajo phenotype. Molecular marker assays were designed based on polymorphism in the C1 vs C1-I alleles. Analysis of a set of 714 inbred lines demonstrated that a combination of two gene-specific markers--8 bp C1-I InDel and C1-I SNP--could predict with high accuracy the presence of anthocyanin color inhibition in the germplasm analyzed. Information generated in this study aids in making informed decisions on the constitution of source populations for doubled haploid (DH) line development in tropical germplasm, particularly those derived from elite maize lines from CIMMYT. The C1-I gene-specific molecular markers identified and validated will facilitate high-throughput and cost-effective evaluation of a large pool of germplasm for the presence of the dominant color inhibitor in maize germplasm.
Carrera Alicia D.
Full Text Available Eight isozyme systems were used in this study: acid phosphatase (ACP, alcohol dehydrogenase (ADH, esterase (EST, glutamate dehydrogenase (GDH, malate dehydrogenase (MDH, phosphoglucoisomerase (PGI, 6-phosphogluconate dehydrogenase (PGD, and phosphoglucomutase (PGM. The polymorphism of these enzyme systems was studied in 25 elite inbred lines. A total of 19 loci were identified, but only eight of them were polymorphic in the germplasm tested. The polymorphic index for the eight informative markers ranged from 0.08 to 0.57, with a mean value of 0.36. Five isozyme loci were mapped in F2:3 populations with existing RFLP data. Est-1, Gdh-2 and Pgi-2 were mapped to linkage groups 3, 14 and 9, respectively. As in previous reports, an ACP locus and a PGD locus were found to be linked, both located in linkage group 2 of the public sunflower map.
Full Text Available Variation at regulatory elements, identified through hypersensitivity to digestion by DNase I, is believed to contribute to variation in complex traits, but the extent and consequences of this variation are poorly characterized. Analysis of terminally differentiated erythroblasts in eight inbred strains of mice identified reproducible variation at approximately 6% of DNase I hypersensitive sites (DHS. Only 30% of such variable DHS contain a sequence variant predictive of site variation. Nevertheless, sequence variants within variable DHS are more likely to be associated with complex traits than those in non-variant DHS, and variants associated with complex traits preferentially occur in variable DHS. Changes at a small proportion (less than 10% of variable DHS are associated with changes in nearby transcriptional activity. Our results show that whilst DNA sequence variation is not the major determinant of variation in open chromatin, where such variants exist they are likely to be causal for complex traits.
Full Text Available Phoma black stem is caused by a widespread pathogen Phoma macdonaldii Boerema.The disease occurs regularly, causing damage by early defoliation and premature ripening.Complete resistance of sunflower to this disease has never been found, but there arereports of differences in response by different genotypes. Fifty-four new inbred lines weretested in our trials conducted at the Rimski Šančevi experimental field. Plants in one trialwere non-irrigated, and irrigated in another. Sunflower plants were artificially inoculatedwith mycelial plugs in the bud stage. The length of stem lesions was measured and comparedusing an analysis of variance. Disease intensity was generally more severe in the nonirrigatedfield. There were significant differences in tolerance to Phoma black stem amongthe tested lines in both trials. The percentage of tolerant genotypes was 1.8%.
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.
The study of lattice varieties is a field that has experienced rapid growth in the last 30 years, but many of the interesting and deep results discovered in that period have so far only appeared in research papers. The aim of this monograph is to present the main results about modular and nonmodular varieties, equational bases and the amalgamation property in a uniform way. The first chapter covers preliminaries that make the material accessible to anyone who has had an introductory course in universal algebra. Each subsequent chapter begins with a short historical introduction which sites the original references and then presents the results with complete proofs (in nearly all cases). Numerous diagrams illustrate the beauty of lattice theory and aid in the visualization of many proofs. An extensive index and bibliography also make the monograph a useful reference work.
Zhang, Yan; Xu, Ling; Fan, Xingming; Tan, Jing; Chen, Wei; Xu, Mingliang
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.
Zhang, H W; Kong, F L
Two sets of NCII mating design including 21 different maize inbreds were used to study the genetic models of five maize kernel traits--kernel length, width, ratio of kernel length and width, kernel thickness and weight per 100 kernels. Ten generations including P1, P2, F1, F2, B1, B2 and their reciprocal crosses RF1, RF2, RB1, RB2 were obtained. Three years' data were obtained and analyzed using mainly two methods: (1) precision identification for single cross and (2) mixed liner model MINQUE approach for diallel design. Method 1 showed that kernel traits were primarily controlled by maternal dominance, endosperm additive and dominance effect (maternal dominance > endosperm additive > endosperm dominance). Cytoplasmic effect was detected in one of the two crosses studied. Method 2 revealed that in the total variance of kernel traits, maternal genotypic effect contributed more than 60%, endosperm genotypic effect contributed less than 40%. Cytoplasmic effect only existed in kernel length and 100 kernel weight, with the range of 10% to 30%. The results indicated that kernel genetic performance was quite largely controlled by maternal genotypic effect.
Widom, Cathy Spatz
There is an implicit assumption of homogeneity across violent behaviors and offenders in the criminology literature. Arguing against this assumption, I draw on three distinct literatures [child abuse and neglect (CAN) and violence, violence and post-traumatic stress disorder (PTSD), and CAN and PTSD] to provide a rationale for an examination of varieties of violent behaviors. I use data from my prospective cohort design study of the long-term consequences of CAN to define three varieties of violent offenders using age of documented cases of CAN, onset of PTSD, and first violent arrest in a temporally correct manner [CAN → to violence, CAN → PTSD → violence (PTSD first), and CAN → violence → PTSD (violence first)], and a fourth variety, violence only. The results illustrate meaningful heterogeneity in violent behavior and different developmental patterns and characteristics. There are three major implications: First, programs and policies that target violence need to recognize the heterogeneity and move away from a "one-size-fits-all" approach. Second, violence prevention policies and programs that target abused and neglected children are warranted, given the prominent role of CAN in the backgrounds of these violent offenders. Third, criminologists and others interested in violence need to attend to the role of PTSD, which is present in about one fifth (21 percent) of these violent offenders, and not relegate the study of these offenders to the psychiatric and psychological literatures.
WIDOM, CATHY SPATZ
There is an implicit assumption of homogeneity across violent behaviors and offenders in the criminology literature. Arguing against this assumption, I draw on three distinct literatures [child abuse and neglect (CAN) and violence, violence and post-traumatic stress disorder (PTSD), and CAN and PTSD] to provide a rationale for an examination of varieties of violent behaviors. I use data from my prospective cohort design study of the long-term consequences of CAN to define three varieties of violent offenders using age of documented cases of CAN, onset of PTSD, and first violent arrest in a temporally correct manner [CAN → to violence, CAN → PTSD → violence (PTSD first), and CAN → violence → PTSD (violence first)], and a fourth variety, violence only. The results illustrate meaningful heterogeneity in violent behavior and different developmental patterns and characteristics. There are three major implications: First, programs and policies that target violence need to recognize the heterogeneity and move away from a “one-size-fits-all” approach. Second, violence prevention policies and programs that target abused and neglected children are warranted, given the prominent role of CAN in the backgrounds of these violent offenders. Third, criminologists and others interested in violence need to attend to the role of PTSD, which is present in about one fifth (21 percent) of these violent offenders, and not relegate the study of these offenders to the psychiatric and psychological literatures. PMID:25505799
Full Text Available To investigate the genetic mechanism of mercury accumulation in maize (Zea mays L., a population of 194 recombinant inbred lines derived from an elite hybrid Yuyu 22, was used to identify quantitative trait loci (QTLs for mercury accumulation at two locations. The results showed that the average Hg concentration in the different tissues of maize followed the order: leaves > bracts > stems > axis > kernels. Twenty-three QTLs for mercury accumulation in five tissues were detected on chromosomes 1, 4, 7, 8, 9 and 10, which explained 6.44% to 26.60% of the phenotype variance. The QTLs included five QTLs for Hg concentration in kernels, three QTLs for Hg concentration in the axis, six QTLs for Hg concentration in stems, four QTLs for Hg concentration in bracts and five QTLs for Hg concentration in leaves. Interestingly, three QTLs, qKHC9a, qKHC9b, and qBHC9 were in linkage with two QTLs for drought tolerance. In addition, qLHC1 was in linkage with two QTLs for arsenic accumulation. The study demonstrated the concentration of Hg in Hg-contaminated paddy soil could be reduced, and maize production maintained simultaneously by selecting and breeding maize Hg pollution-safe cultivars (PSCs.
Nitrate (NOequation image) and ammonium (NHequation image) are the predominant forms of nitrogen (N) available to plants in agricultural soils. Nitrate concentrations are generally ten times higher than those of NHequation image and this ratio is consistent across a wide range of soil types. The possible contribution of these small concentrations of NHequation image to the overall N budget of crop plants is often overlooked. In this study the importance of this for the growth and nitrogen budget of maize (Zea mays L.) was investigated, using agriculturally relevant concentrations of NHequation image. Maize inbred line B73 was grown hydroponically for 30 d at low (0.5 mM) and sufficient (2.5 mM) levels of NOequation image. Ammonium was added at 0.05 mM and 0.25 mM to both levels of NOequation image. At low NOequation image levels, addition of NHequation image was found to improve the growth of maize plants. This increased plant growth was accompanied by an increase in total N uptake, as well as total phosphorus, sulphur and other micronutrients in the shoot. Ammonium influx was higher than NOequation image influx for all the plants and decreased as the total N in the nutrient medium increased. This study shows that agriculturally relevant proportions of NHequation image supplied in addition to NOequation image can increase growth of maize.
Mei, Yu; Kernodle, Bliss M.; Hill, John H.
Plant viruses have been widely used as vectors for foreign gene expression and virus-induced gene silencing (VIGS). A limited number of viruses have been developed into viral vectors for the purposes of gene expression or VIGS in monocotyledonous plants, and among these, the tripartite viruses Brome mosaic virus and Cucumber mosaic virus have been shown to induce VIGS in maize (Zea mays). We describe here a new DNA-based VIGS system derived from Foxtail mosaic virus (FoMV), a monopartite virus that is able to establish systemic infection and silencing of endogenous maize genes homologous to gene fragments inserted into the FoMV genome. To demonstrate VIGS applications of this FoMV vector system, four genes, phytoene desaturase (functions in carotenoid biosynthesis), lesion mimic22 (encodes a key enzyme of the porphyrin pathway), iojap (functions in plastid development), and brown midrib3 (caffeic acid O-methyltransferase), were silenced and characterized in the sweet corn line Golden × Bantam. Furthermore, we demonstrate that the FoMV infectious clone establishes systemic infection in maize inbred lines, sorghum (Sorghum bicolor), and green foxtail (Setaria viridis), indicating the potential wide applications of this viral vector system for functional genomics studies in maize and other monocots. PMID:27208311
Mei, Yu; Zhang, Chunquan; Kernodle, Bliss M; Hill, John H; Whitham, Steven A
Plant viruses have been widely used as vectors for foreign gene expression and virus-induced gene silencing (VIGS). A limited number of viruses have been developed into viral vectors for the purposes of gene expression or VIGS in monocotyledonous plants, and among these, the tripartite viruses Brome mosaic virus and Cucumber mosaic virus have been shown to induce VIGS in maize (Zea mays). We describe here a new DNA-based VIGS system derived from Foxtail mosaic virus (FoMV), a monopartite virus that is able to establish systemic infection and silencing of endogenous maize genes homologous to gene fragments inserted into the FoMV genome. To demonstrate VIGS applications of this FoMV vector system, four genes, phytoene desaturase (functions in carotenoid biosynthesis), lesion mimic22 (encodes a key enzyme of the porphyrin pathway), iojap (functions in plastid development), and brown midrib3 (caffeic acid O-methyltransferase), were silenced and characterized in the sweet corn line Golden × Bantam. Furthermore, we demonstrate that the FoMV infectious clone establishes systemic infection in maize inbred lines, sorghum (Sorghum bicolor), and green foxtail (Setaria viridis), indicating the potential wide applications of this viral vector system for functional genomics studies in maize and other monocots. © 2016 American Society of Plant Biologists. All Rights Reserved.
Li, Dan; Wang, Xufeng; Zhang, Xiangbo; Chen, Qiuyue; Xu, Guanghui; Xu, Dingyi; Wang, Chenglong; Liang, Yameng; Wu, Lishuan; Huang, Cheng; Tian, Jinge; Wu, Yaoyao; Tian, Feng
The number of leaves and their distributions on plants are critical factors determining plant architecture in maize (Zea mays), and leaf number is frequently used as a measure of flowering time, a trait that is key to local environmental adaptation. Here, using a large set of 866 maize-teosinte BC2 S3 recombinant inbred lines genotyped by using 19,838 single nucleotide polymorphism markers, we conducted a comprehensive genetic dissection to assess the genetic architecture of leaf number and its genetic relationship to flowering time. We demonstrated that the two components of total leaf number, the number of leaves above (LA) and below (LB) the primary ear, were under relatively independent genetic control and might be subject to differential directional selection during maize domestication and improvement. Furthermore, we revealed that flowering time and leaf number are commonly regulated at a moderate level. The pleiotropy of the genes ZCN8, dlf1 and ZmCCT on leaf number and flowering time were validated by near-isogenic line analysis. Through fine mapping, qLA1-1, a major-effect locus that specifically affects LA, was delimited to a region with severe recombination suppression derived from teosinte. This study provides important insights into the genetic basis of traits affecting plant architecture and adaptation. The genetic independence of LA from LB enables the optimization of leaf number for ideal plant architecture breeding in maize. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.
Full Text Available Preharvest sprouting reduces the maize quality and causes a significant yield loss in maize production. vp-wl2 is a Mutator (Mu-induced viviparous mutant in maize, causing white or pale yellow kernels, dramatically reduced carotenoid and ABA content, and a high level of zeta-carotene accumulation. Here, we reported the cloning of the vp-wl2 gene using a modified digestion-ligation-amplification method (DLA. The results showed that an insertion of Mu9 in the first intron of the zeta-carotene desaturase (ZDS gene results in the vp-wl2 mutation. Previous studies have suggested that ZDS is likely the structural gene of the viviparous9 (vp9 locus. Therefore, we performed an allelic test using vp-wl2 and three vp9 mutants. The results showed that vp-wl2 is a novel allele of the vp9 locus. In addition, the sequences of ZDS gene were identified in these three vp9 alleles. The vp-wl2 mutant gene was subsequently introgressed into four maize inbred lines, and a viviparous phenotype was observed with yield losses from 7.69% to 13.33%.
Wang, Xinjun; Cao, Haihe; Zhang, Dengfeng; Li, Bo; He, Yan; Li, Jiansheng; Wang, Shoucai
Maize (Zea mays L.) is one of the most important crops because of the remarkable properties of its hybrid, which is responsible for the high commercial value of hybrid maize. The genetic basis of heterosis (hybrid vigor) is not well understood. A differential display technique was performed to identify genes with differential expression across twelve maize inbred lines and thirty-three hybrids during ear development. An incomplete diallel design was used to investigate the relationship between the global framework of differential gene expression and heterosis. It was found that the genes belonging to MONO pattern (i.e., genes expressed in both parental lines and in hybrid) was the highest in percentage among the total five patterns and illustrated that the properties of differentially expressed genes are not entirely responsible for heterosis. Furthermore, a larger number of differentially expressed genes in hybrid, which serves as a major reservoir for generating novel phenotypes that exhibit heterosis of certain agronomic traits during early development and differentiation of maize ear. Moreover, there were some silent genesin hybrids that are responsible for the arrest or abortion of spikelets and for the increase in kernels weight.
Full Text Available In this study, seventy two sunflower recombinant inbred lines were tested for their yielding ability under both water-stressed and well-watered states. The inbred lines were evaluated in a rectangular 8´9 lattice design with two replications in both well-watered and water-stressed conditions, separately. Eight drought tolerance indices including stability tolerance index (STI, mean productivity (MP, geometric mean productivity (GMP, harmonic mean (HM, stress susceptibility index (SSI, tolerance index (TOL, yield index (YI and yield stability index (YSI were calculated based on grain yield for every genotype. Results showed the highest values of mean productivity (MP index, geometric mean productivity (GMP, yield index (YI, harmonic mean (HM and stress tolerance index (STI indices for ‘C134a’ inbred line and least values of stress susceptibility index (SSI and tolerance (TOL for C61 inbred line. According to correlation of indices with yield performance under both drought stress and non-stress states and principle component analysis, indices including HM, MP, GMP and STI could properly distinguish drought tolerant sunflower inbred lines with high yield performance under both states. Cluster analysis of inbred lines using Ys, Yp and eight indices, categorized them into four groups including 19, 6, 26 and 19 inbred lines.
Thompson, Addie M.; Yu, Jianming; Timmermans, Marja C. P.; Schnable, Patrick; Crants, James E.; Scanlon, Michael J.; Muehlbauer, Gary J.
The shoot apical meristem contains a pool of undifferentiated stem cells and controls initiation of all aerial plant organs. In maize (Zea mays), leaves are formed throughout vegetative development; on transition to floral development, the shoot meristem forms the tassel. Due to the regulated balance between stem cell maintenance and organogenesis, the structure and morphology of the shoot meristem are constrained during vegetative development. Previous work identified loci controlling meristem architecture in a recombinant inbred line population. The study presented here expanded on this by investigating shoot apical meristem morphology across a diverse set of maize inbred lines. Crosses of these lines to common parents showed varying phenotypic expression in the F1, with some form of heterosis occasionally observed. An investigation of meristematic growth throughout vegetative development in diverse lines linked the timing of reproductive transition to flowering time. Phenotypic correlations of meristem morphology with adult plant traits showed an association between the meristem and flowering time, leaf shape, and yield traits, revealing links between the control and architecture of undifferentiated and differentiated plant organs. Finally, quantitative trait loci mapping was utilized to map the genetic architecture of these meristem traits in two divergent populations. Control of meristem architecture was mainly population-specific, with 15 total unique loci mapped across the two populations with only one locus identified in both populations. PMID:25748433
Marcon, Caroline; Schützenmeister, André; Schütz, Wolfgang; Madlung, Johannes; Piepho, Hans-Peter; Hochholdinger, Frank
Heterosis describes the superior performance of heterozygous F(1)-hybrid plants compared to their homozygous parental inbred lines. In the present study, heterosis was detected for length, weight, and the time point of seminal root primordia initiation in maize (Zea mays L.) embryos of the reciprocal F(1)-hybrids UH005xUH250 and UH250xUH005. A two-dimensional gel electrophoresis (2-DE) proteome survey of the most abundant proteins of the reciprocal hybrids and their parental inbred lines 25 and 35 days after pollination revealed that 141 of 597 detected proteins (24%) exhibited nonadditive accumulation in at least one hybrid. Approximately 44% of all nonadditively accumulated proteins displayed an expression pattern that was not distinguishable from the low parent value. Electrospray ionization-tandem mass spectrometry (ESI-MS/MS) analyses and subsequent functional classification of the 141 proteins revealed that development, protein metabolism, redox-regulation, glycolysis, and amino acid metabolism were the most prominent functional classes among nonadditively accumulated proteins. In 35-day-old embryos of the hybrid UH250xUH005, a significant up-regulation of enzymes related to glucose metabolism which often exceeded the best parent values was observed. A comparison of nonadditive protein accumulation between rice and maize embryo data sets revealed a significant overlap of nonadditively accumulated proteins suggesting conserved organ- or tissue-specific regulatory mechanisms in monocots related to heterosis.
Full Text Available Stamena is a winter wheat variety developed at the Institute of Field and Vegetable Crops in Novi Sad, Yugoslavia. It was released by the Federal Commission for varietals Approval in 1999. Stamena was developed by crossing genetically divergent and highly productive parents Lasta and Rodna (Breeders: T. Mišić. N. Mladenov, Z. Jerković and R. Jevtić. Spike is white, smooth, awn less, medium compact with 18-21 spike lets. The grain is vitreous and dark red (Triticum aestivum L. ssp. vulgar e var. lutescens. Stamena is a medium early variety, 1 day earlier than Partizanka and 3 days earlier than Jugoslavija (Table 4. It has excellent resistance to winterkilling, as in very winter hardy Partizanka. The average stem height is 78 cm, with a good resistance to lodging. Stamena has field resistance to leaf rust (Pucce, recondita tritict, horizontal resistance, which is the type of resistance that modern wheat breeding is interested in. The resistance to stem rust (Pucce, graminis tritict is good and to powdery mildew (Erysiphegraminis tritici very good. The 1000 grain mass is about 32 g and volume grain mass 81.3 kg/hi. (Table 2. Stamena is classified in the subgroup A-l. It has excellent milling and baking quality and it belong to the 1st technological group (quality enhancer. The quantity of dry gluten is about 9%. The variety Stamena is a very productive, with the genetic potential for grain above 11 t/ha suitable for growing on fertile and less fertile soils. It has started to be grown commercially in 2000.
Tai, Huanhuan; Lu, Xin; Opitz, Nina; Marcon, Caroline; Paschold, Anja; Lithio, Andrew; Nettleton, Dan; Hochholdinger, Frank
Maize develops a complex root system composed of embryonic and post-embryonic roots. Spatio-temporal differences in the formation of these root types imply specific functions during maize development. A comparative transcriptomic study of embryonic primary and seminal, and post-embryonic crown roots of the maize inbred line B73 by RNA sequencing along with anatomical studies were conducted early in development. Seminal roots displayed unique anatomical features, whereas the organization of primary and crown roots was similar. For instance, seminal roots displayed fewer cortical cell files and their stele contained more meta-xylem vessels. Global expression profiling revealed diverse patterns of gene activity across all root types and highlighted the unique transcriptome of seminal roots. While functions in cell remodeling and cell wall formation were prominent in primary and crown roots, stress-related genes and transcriptional regulators were over-represented in seminal roots, suggesting functional specialization of the different root types. Dynamic expression of lignin biosynthesis genes and histochemical staining suggested diversification of cell wall lignification among the three root types. Our findings highlight a cost-efficient anatomical structure and a unique expression profile of seminal roots of the maize inbred line B73 different from primary and crown roots. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.
Richetti, J.; Ahmad, I.; Aristizabal, F.; Judge, J.
Determining maize agricultural production under climate variability is valuable to policy makers in Pakistan since maize is the third most produced crop by area after wheat and rice. This study aims to predict the maize production under climate variability. Two-hundred ground truth points of both maize and non-maize land covers were collected from the Faisalabad district during the growing seasons of 2015 and 2016. Landsat-8 images taken in second week of May which correspond spatially and temporally to the local, peak growing season for maize were gathered. For classifying the region training data was constructed for a variety of machine learning algorithms by sampling the second, third, and fourth bands of the Landsat-8 imagery at these reference locations. Cross validation was used for parameter tuning as well as estimating the generalized performances. All the classifiers resulted in overall accuracies of greater than 90% for both years and a support vector machine with a radial basis kernel recorded the maximum accuracy of 97%. The tuned models were used to determine the spatial distribution of maize fields for both growing seasons in the Faisalabad district using parallel processing to improve computation time. The overall classified maize growing area represented 12% difference than that reported by the Crop Reporting Service (CRS) of Punjab Pakistan for both 2015 and 2016. For the agricultural production normalized difference vegetation index from Landsat-8 and climate indicators from ground stations will be used as inputs in a variety of machine learning regression algorithms. The expected results will be compared to actual yield from 64 commercial farms. To verify the impact of climate variability in the maize agricultural production historical climate data from previous 30 years will be used in the developed model to asses the impact of climate variability on the maize production.
Xu, Jie; Wang, Qi; Freeling, Micheal; Zhang, Xuecai; Xu, Yunbi; Mao, Yan; Tang, Xin; Wu, Fengkai; Lan, Hai; Cao, Moju; Rong, Tingzhao
Abstract Natural antisense transcripts (NATs) are a prominent and complex class of regulatory RNAs. Using strand-specific RNA sequencing, we identified 1769 sense and antisense transcript pairs (NAT pairs) in two maize inbreds with different sensitivity to drought, as well as in two derivative recombination inbred lines (RILs). A significantly higher proportion of NATs relative to non-NATs are specifically expressed under water stress (WS). Surprisingly, expression of sense and antisense transcripts produced by NAT pairs is significantly correlated, particularly under WS. We found an unexpected large proportion of NATs with protein coding potential, as estimated by ribosome release scores. Small RNAs significantly accumulate within NAT pairs, with 21 nt smRNA particularly enriched in overlapping regions of these pairs of genes. The abundance of these smRNAs is significantly altered in the leafbladeless1 mutant, suggesting that these genes may be regulated by the tasiRNA pathway. Further, NATs are significantly hypomethylated and include fewer transposable element sequences relative to non-NAT genes. NAT gene regions also exhibit higher levels of H3K36me3, H3K9ac, and H3K4me3, but lower levels of H3K27me3, indicating that NAT gene pairs generally exhibit an open chromatin configuration. Finally, NAT pairs in 368 diverse maize inbreds and 19 segregating populations were specifically enriched for polymorphisms associated with drought tolerance. Taken together, the data highlight the potential impact of that small RNAs and histone modifications have in regulation of NAT expression, and the significance of NATs in response to WS. PMID:28175341
Full Text Available According to the analysis of variance, a genotype, year and a genotype x year interaction significantly affect variability of the trait number of kernel rows per ear. This number was the highest in the silage maize inbred lines ZPLB402, ZPLB403 and ZPLB405 in both years of investigation, resulting in low both positive and negative values of heterosis. The correct estimation of combining abilities is necessary in order to develop superior hybrids. This estimation was done on the basis of diallel hybrids after the method of Griffing (1956; method II, model I. The analysis of variance for combining abilities for the number of kernel rows per ear points to the significance of general and special combining abilities. The GCA to SCA ratio indicates that additive genes and the additive variance have a significant role in inheritance of this trait. Highly significant values of GCA for the number of kernel rows per ear for both years were found in the silage maize inbred lines ZPLB402 and ZPLB403, whereas inbreds ZPLB401, ZPLB404 and ZPLB406 had negative values. Highly significant positive, i.e. negative values of SCA for the number of kernel rows per ear for both years were found in the hybrid combinations ZPLB402 x ZPLB405 and ZPLB402 x ZPLB406, i.e. ZPLB402 x ZPLB406, respectively. Highly significant effects of SCA in hybrid combinations that include both parents with low GCA values are probably a result of the interaction among additive genes in parents. .
Nahampun, Hartinio N; López-Arredondo, Damar; Xu, Xing; Herrera-Estrella, Luis; Wang, Kan
Bacterial phosphite oxidoreductase gene and chemical phosphite can be used as a selection system for Agrobacterium -mediated maize transformation. Application of phosphite (Phi) on plants can interfere the plant metabolic system leading to stunted growth and lethality. On the other hand, ectopic expression of the ptxD gene in tobacco and Arabidopsis allowed plants to grow in media with Phi as the sole phosphorous source. The phosphite oxidoreductase (PTXD) enzyme catalyzes the conversion of Phi into phosphate (Pi) that can then be metabolized by plants and utilized as their essential phosphorous source. Here we assess an alternative selectable marker based on a bacterial ptxD gene for Agrobacterium-mediated maize transformation. We compared the transformation frequencies of maize using either the ptxD/Phi selection system or a standard herbicide bar/bialaphos selection system. Two maize genotypes, a transformation amenable hybrid Hi II and an inbred B104, were tested. Transgene presence, insertion copy numbers, and ptxD transcript levels were analyzed and compared. This work demonstrates that the ptxD/Phi selection system can be used for Agrobacterium-mediated maize transformation of both type I and type II callus culture and achieve a comparable frequency as that of the herbicide bar/bialaphos selection system.
Guan, Ya-jing; Hu, Jin; Wang, Xian-ju; Shao, Chen-xia
Low temperature stress during germination and early seedling growth is an important constraint of global production of maize. The effects of seed priming with 0.25%, 0.50%, and 0.75% (w/v) chitosan solutions at 15 °C on the growth and physiological changes were investigated using two maize (Zea mays L.) inbred lines, HuangC (chilling-tolerant) and Mo17 (chilling-sensitive). While seed priming with chitosan had no significant effect on germination percentage under low temperature stress, it enhanced germination index, reduced the mean germination time (MGT), and increased shoot height, root length, and shoot and root dry weights in both maize lines. The decline of malondialdehyde (MDA) content and relative permeability of the plasma membrane and the increase of the concentrations of soluble sugars and proline, peroxidase (POD) activity, and catalase (CAT) activity were detected both in the chilling-sensitive and chilling-tolerant maize seedlings after priming with the three concentrations of chitosan. HuangC was less sensitive to responding to different concentrations of chitosan. Priming with 0.50% chitosan for about 60~64 h seemed to have the best effects. Thus, it suggests that seed priming with chitosan may improve the speed of germination of maize seed and benefit for seedling growth under low temperature stress. PMID:19489108
Guan, Ya-jing; Hu, Jin; Wang, Xian-ju; Shao, Chen-xia
Low temperature stress during germination and early seedling growth is an important constraint of global production of maize. The effects of seed priming with 0.25%, 0.50%, and 0.75% (w/v) chitosan solutions at 15 degrees C on the growth and physiological changes were investigated using two maize (Zea mays L.) inbred lines, HuangC (chilling-tolerant) and Mo17 (chilling-sensitive). While seed priming with chitosan had no significant effect on germination percentage under low temperature stress, it enhanced germination index, reduced the mean germination time (MGT), and increased shoot height, root length, and shoot and root dry weights in both maize lines. The decline of malondialdehyde (MDA) content and relative permeability of the plasma membrane and the increase of the concentrations of soluble sugars and proline, peroxidase (POD) activity, and catalase (CAT) activity were detected both in the chilling-sensitive and chilling-tolerant maize seedlings after priming with the three concentrations of chitosan. HuangC was less sensitive to responding to different concentrations of chitosan. Priming with 0.50% chitosan for about 60 approximately 64 h seemed to have the best effects. Thus, it suggests that seed priming with chitosan may improve the speed of germination of maize seed and benefit for seedling growth under low temperature stress.
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.
Mathur, Chandni; Kathuria, Pooran C.; Dahiya, Pushpa; Singh, Anand B.
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
Murty, V Kumar
The book represents an introduction to the theory of abelian varieties with a view to arithmetic. The aim is to introduce some of the basics of the theory as well as some recent arithmetic applications to graduate students and researchers in other fields. The first part contains proofs of the Abel-Jacobi theorem, Riemann's relations and the Lefschetz theorem on projective embeddings over the complex numbers in the spirit of S. Lang's book Introduction to algebraic and abelian functions. Then the Jacobians of Fermat curves as well as some modular curves are discussed. Finally, as an application, Faltings' proof of the Mordell conjecture and its intermediate steps, the Tate conjecture and the Shafarevich conjecture, are sketched. - H. Lange for MathSciNet.
Nielsen, Rasmus Kleis
News media organizations like newspapers and broadcasters have long functioned as gatekeepers between news and audiences, but with the rise of digital media, the search engines and social networking sites that are central to how most people find news online increasingly complement news media......-Nahon, 2008; Introna and Nissenbaum, 2000; Thorston and Wells, 2012) have highlighted the need for a broader approach to gatekeeping in wider networked information environments where digital technologies are increasingly integral to traditional gatekeeping practices and where non-journalistic actors...... increasingly serve as gates between news and audiences (Anderson, 2011; Coddington and Holton, 2013; Meraz and Papacharissi, 2013). In this paper, I adopt such a broader approach and outline three varieties of online gatekeeping that each integrate digital technologies in the gatekeeping process, but do so...
The objective of this study was to investigate the occurrence of total aflatoxin and total fumonisin in maize and maize-based products in Babati, northern Tanzania. A total of 160 samples were collected in 2013-14. Quantification for total aflatoxin and fumonisin was done using enzyme-linked immunosorbent assay (Reveal ...
Yin, Xiaogang; Olesen, Jørgen Eivind; Wang, M.
Maize (Zea mays L.) is the most prominent crop in the Northeast Farming Region of China (NFR), and drought has been the largest limitation for maize production in this area during recent decades. The question of how to adapt maize production to drought has received great attention from policy...... counties across NFR. Our survey results indicated that using variety diversification, drought resistant varieties and dibbling irrigation are the three major adaptation strategies against drought in spring, and farmers also adopted changes in sowing time, conservation tillage and mulching to cope...... makers, researchers and farmers. In order to evaluate the effects of adaptation strategies against drought and examine the influences of policy supports and farmer households’ characteristics on adopting decisions, a large scale household survey was conducted in five representative maize production...
Full Text Available Maize is one of the most widely cultivated crops. It accumulates a large quantity of seed storage proteins, which are important for seed development and germination, and contribute to the nutritional quality of seeds. Based on solubility, the storage proteins are divided into albumins (water-soluble, globulins (salt-soluble, prolamins (alcohol-soluble, and glutelins (acid- or alkali-soluble. Maize hybrids are cultivated due to the superior performance of F1 hybrids than that of their parents, a phenomenon known as heterosis. However, the accumulation patterns of seed storage proteins in maize embryos between the hybrids and their parental inbred lines have not been compared. In the present study, two elite inbred lines of China, Zheng 58 and Chang 7-2, and their reciprocal hybrids (Zheng 58 × Chang 7-2 and Chang 7-2 × Zheng 58 were used to explore parental influences on the accumulation patterns of seed storage proteins in maize embryos. For this purpose, we focused on seed salt-soluble proteins (SSPs in our experiments. The SSPs were selectively extracted from maize mature embryos after extensive removal of water-soluble albumin and separated using two-dimensional gel electrophoresis (2-DE, followed by mass spectrometry analysis. Our results indicated that the 2-DE SSP profiles of hybrids closely resembled those of their maternal parent rather than the paternal parent. In other words, 2-DE SSP profiles of Zheng 58 × Chang 7-2 were more similar those of Zheng 58 whereas such profiles of Chang 7-2 × Zheng 58 were more similar to those of Chang 7-2 although the 2-DE profiles of all four maize types were quite similar. In total, 12 relatively abundant SSPs spots representing five kinds of proteins were identified, of which nine protein spots displayed non-additive accumulation in at least one hybrid. This study provided additional data on dominance and partial dominance effects on maize hybrids embryos. Besides, earlier studies on accumulation
Ortiz-García, S.; Ezcurra, E.; Schoel, B.; Acevedo, F.; Soberón, J.; Snow, A. A.
In 2000, transgenes were detected in local maize varieties (landraces) in the mountains of Oaxaca, Mexico [Quist, D. & Chapela, I. H. (2001) Nature 414, 541–543]. This region is part of the Mesoamerican center of origin for maize (Zea mays L.), and the genetic diversity that is maintained in open-pollinated landraces is recognized as an important genetic resource of great cultural value. The presence of transgenes in landraces was significant because transgenic maize has never been approved for cultivation in Mexico. Here we provide a systematic survey of the frequency of transgenes in currently grown landraces. We sampled maize seeds from 870 plants in 125 fields and 18 localities in the state of Oaxaca during 2003 and 2004. We then screened 153,746 sampled seeds for the presence of two transgene elements from the 35S promoter of the cauliflower mosaic virus and the nopaline synthase gene (nopaline synthase terminator) from Agrobacterium tumefaciens. One or both of these transgene elements are present in all transgenic commercial varieties of maize. No transgenic sequences were detected with highly sensitive PCR-based markers, appropriate positive and negative controls, and duplicate samples for DNA extraction. We conclude that transgenic maize seeds were absent or extremely rare in the sampled fields. This study provides a much-needed preliminary baseline for understanding the biological, socioeconomic, and ethical implications of the inadvertent dispersal of transgenes from the United States and elsewhere to local landraces of maize in Mexico. PMID:16093316
Histocompatible chicken inbred lines: homogeneities in the major histocompatibility complex antigens of the GSP, GSN/1, PNP/DO and BM-C inbred lines assessed by hemagglutination, mixed lymphocyte reaction and skin transplantation.
Valdez, Marcos B; Mizutani, Makoto; Fujiwara, Akira; Yazawa, Hajime; Yamagata, Takahiro; Shimada, Kiyoshi; Namikawa, Takao
Chicken inbred lines of the GSP, GSN/1, PNP/DO and BM-C have been established by selection of a specific allele at the B blood group locus (MHC B-G region) and other polymorphic loci through pedigree mating. To extend the potential of these inbred lines as experimental animals in Aves, we assessed the antigenic homogeneities of the MHC antigens by three immunological methods. Antigenic variations of red blood cells (RBCs) were surveyed in the inbred lines and a random-bred line (NG) derived from the Nagoya breed by using ten kinds of intact antisera produced in the inbred line of chickens against RBCs of a red junglefowl and hybrids. In the hemagglutination test, no individual variations were found within the inbred line at all, while all the ten antisera detected highly heterogeneous reactions in individuals of the NG. The reciprocal one-way mixed lymphocyte reactions gave constantly higher stimulation responses (PGSP and GSN/1 inbred lines both having the B(21) allele. In reciprocal skin transplantation, the transplanted skingrafts within the inbred line and between individuals from the GSP and GSN/1 inbred lines survived more than 100 days, while all the skingrafts showed signs of rejection within 7 days among the inbred lines having different B alleles. The results obtained by the three practical methods coincidentally indicated that the individuals in the respective four inbred lines were histocompatible, and further, that the GSP and GSN/1 individuals were histocompatible.
Velasquez, Sarah E; Abraham, K; Burnett, Tim G; Chapin, Bridgett; Hendry, William J; Leung, Sam; Madden, Michael E; Rider, Virginia; Stanford, John A; Ward, Robert E; Chapes, Stephen K
The Kansas-IDeA Network of Biomedical Research Excellence (K-INBRE) is an infrastructure-building program funded by the National Institute of General Medical Sciences. Undergraduate education, through undergraduate research, is a key component of the program. The K-INBRE network includes 10 higher education institutions in Kansas and northern Oklahoma, with over 1,000 student participants in 16 yr. Since 2003, the K-INBRE has held an annual state-wide research symposium that includes national and regional speakers and provides a forum for undergraduates to give platform and poster presentations. The symposium is well attended by K-INBRE participants and has grown to a size of over 300 participants per year from all 10 K-INBRE schools. Two surveys were distributed to students and mentors to assess the impact of the symposium on student learning. Surveys (153) were distributed to students who participated in K-INBRE from 2013 through 2015 with a 51% response rate. Mentors were surveyed with a response of 111 surveys out of 161. Survey results indicate that students and mentors alike find the symposium to be beneficial and enriching of the student experience. Almost 80% of student respondents indicated that their participation in the symposium fostered appreciation of research. In short, the K-INBRE symposium provides a unique opportunity for students to gain experience in collecting, preparing, and communicating research in a professional environment. The collaborative experience of the annual K-INBRE symposium, the impact it has on student learning, and how it has influenced the research culture at our 10 institutions will be described.
ABSTRACT. This study analysed fresh maize cob losses and its effect on the poverty status of maize farmers in Edo State,. Nigeria. The specific objectives were to estimate the physical and financial amount of fresh maize cob losses experienced by maize farmers, examine the effect of fresh maize cob losses on the ...
The investigations pointed out the genotypic and phenotypic differences in growth between varieties and their relationship to economic yield. Leaf area development (LAD) was important in the accumulation of dry matter and led to higher grain yield in maize. As expected, the early-maturing variety ('Dorke') showed a ...
This book is motivated by the problem of determining the set of rational points on a variety, but its true goal is to equip readers with a broad range of tools essential for current research in algebraic geometry and number theory. The book is unconventional in that it provides concise accounts of many topics instead of a comprehensive account of just one-this is intentionally designed to bring readers up to speed rapidly. Among the topics included are Brauer groups, faithfully flat descent, algebraic groups, torsors, étale and fppf cohomology, the Weil conjectures, and the Brauer-Manin and descent obstructions. A final chapter applies all these to study the arithmetic of surfaces. The down-to-earth explanations and the over 100 exercises make the book suitable for use as a graduate-level textbook, but even experts will appreciate having a single source covering many aspects of geometry over an unrestricted ground field and containing some material that cannot be found elsewhere. The origins of arithmetic (o...
Waldelice Oliveira de Paiva
Full Text Available Com o objetivo de produzir híbridos de melão adaptados à região Nordeste do Brasil, foi avaliado, em Pacajús-CE o comportamento de 29 linhagens, sendo 23 do grupo cantalupensis, cinco do inodorus e uma do grupo momordica. Para efeito de comparação, foram utilizadas cultivares comerciais: o híbrido Hy-mark e a cultivar Eldorado-300. Na avaliação da precocidade a maturação das linhagens do grupo cantalupensis levaram em média 35,1 dias, as do grupo inodorus 30,6 dias e as do grupo momordica 24,4 dias. A concentração da produção, estimada aos 70 dias, foi mais elevada (75,8% numa linhagem que não produz frutos comerciais. A produção das linhagens variou de 16,2 t/ha a 65,1 t/ha, enquanto a média das testemunhas comerciais foi de 28,4 t/ha. Três linhagens do grupo cantalupensis e todas do grupo inodorus mostraram-se mais produtivas que as testemunhas. O teor de sólidos solúveis entre linhagens e testemunhas foi semelhante (8,6%, sendo que uma das linhagens, M46-00 se destacou pelos altos teores (Brix=12,2%. Em geral, os frutos das linhagens tardias mostraram elevado teor de sólidos solúveis.In order to obtain melon hybrids adapted for growing in the Northeast of Brazil, 29 inbred lines (23 belonging to the cantaloupensis group, 5 to the inodorus and 1 to the momordica group were evaluated in Pacajus, in the state of Ceará. Two commercial varieties, the hybrid Hy-mark and the cultivar Eldorado-300, were used as checks. It was observed that the average period for fruit ripening was 35.1 days for the cantalupensis group, 30.6 days for the inodorus group and 24.4 days for the momordica group. The highest yield concentration (75.8%, evaluated 70 days after sowing, was attained in a inbred line that does not produce commercial fruits. The yield of the lines ranged from 16.2 t/ha up to 65.1 t/ha, whereas the two commercial varieties produced 28.0 t/ha. Three of the cantalupensis group and all inbred lines of the inodorus group
Full Text Available The use of modern crop varieties is a dominant method of obtaining high yields in crop production. Efforts to identify suitable varieties, with characteristics that would increase crop yield under future climate conditions, remain essential to developing sustainable agriculture and food security. This work aims to evaluate potential genotypic adaptations (i.e., using varieties with increased ability to produce desirable grain numbers under high temperatures and with enhanced thermal time requirements during the grain-filling period to cope with the negative impacts of climate change on maize yield. The contributions of different options were investigated at six sites in the North China Plain using the APSIM model and the outputs of 8 GCMs under RCP4.5 scenarios. It was found that without considering adaptation options, mean maize yield would decrease by 7~18% during 2010-2039 relative to 1976-2005. A large decrease in grain number relative to stabilized grain weight decreased maize yield under future climate scenarios. Using heat-tolerant varieties, maize yield could increase on average by 6% to 10%. Using later maturing varieties, e.g., enhanced thermal time requirements during the grain-filling period, maize yield could increase by 7% to 10%. The optimal adaptation options were site specific.
Mice from 13 inbred strains (S, Z, E, Bab, BaB, BrR, C, K, N, Q, G, CFW, CF1) received continuous cobalt 60 irradiation at low dose rates for varying numbers of consecutive generations. Some Bab and BaB mice had received continuous irradiation for from 24 to 31 generations and the other mice had up to six generations of continuous irradiation in their ancestry. At weaning, the mice were removed from the irradiation room and were mated within strains either to sibs or nonsibs. Ancestral and direct irradiation doses were calculated. The ancestral dose was the effective accumulated dose to the progeny of the mated mice. The direct dose was the amount of irradiation received by any mated female from her conception to her weaning. Each irradiated or control female was scored as fertile or sterile and in utero litter counts were made in pregnant females that were dissected past the tenth day of pregnancy; the sum of moles, dead embryos, and live embryos was the total in utero litter size. A ratio of the living embryos to the total number of embryos in utero was determined for each litter. An increase in ancestral or direct irradiation dose significantly decreased fertility in 11 of the 13 strains. The fertility curves for the pooled data were sigmoid in the area of the doses below those that caused complete sterility. Among the controls, there were significant strain differences in total litter size and in the ratio. Strain X--Y plots, with ancestral or direct doses plotted against total litter size or ratio, revealed the tendency for litter size to decrease as dose increased. The only trend shown for ratio was for the litters with ratios of 0.50 or less to appear more frequently among the irradiated mice. The few corpora lutea counts revealed nothing of significance. Generally, there was a definite trend toward fewer mice alive in utero among the irradiated mice
Liu, Yan; Zhang, Zhiqiang; Fu, Junjie; Wang, Guoying; Wang, Jianhua; Liu, Yunjun
Maize Agrobacterium-mediated transformation efficiency has been greatly improved in recent years. Antioxidants, such as, cysteine, can significantly improve maize transformation frequency through improving the Agrobacterium infection efficiency. However, the mechanism underlying the transformation improvement after cysteine exposure has not been elucidated. In this study, we showed that the addition of cysteine to the co-cultivation medium significantly increased the Agrobacterium infection efficiency of hybrid HiII and inbred line Z31 maize embryos. Reactive oxygen species contents were higher in embryos treated with cysteine than that without cysteine. We further investigated the mechanism behind cysteine-related infection efficiency increase using transcriptome analysis. The results showed that the cysteine treatment up-regulated 939 genes and down-regulated 549 genes in both Z31 and HiII. Additionally, more differentially expressed genes were found in HiII embryos than those in Z31 embryos, suggesting that HiII was more sensitive to the cysteine treatment than Z31. GO analysis showed that the up-regulated genes were mainly involved in the oxidation reduction process. The up-regulation of these genes could help maize embryos to cope with the oxidative stress stimulated by Agrobacterium infection. The down-regulated genes were mainly involved in the cell wall and membrane metabolism, such as, aquaporin and expansin genes. Decreased expression of these cell wall integrity genes could loosen the cell wall, thereby improving the entry of Agrobacterium into plant cells. This study offers insight into the role of cysteine in improving Agrobacterium-mediated transformation of maize immature embryos. PMID:29089955
Di Fenza, Mauro; Hogg, Bridget; Grant, Jim; Barth, Susanne
Maize ( Zea mays ) is a C 4 tropical cereal and its adaptation to temperate climates can be problematic due to low soil temperatures at early stages of establishment. In the current study we have firstly investigated the physiological response of twelve maize varieties, from a chilling condition adapted gene pool, to sub-optimal growth temperature during seedling emergence. To identify transcriptomic markers of cold tolerance in already adapted maize genotypes, temperature conditions were set below the optimal growth range in both control and low temperature groups. The conditions were as follows; control (18 °C for 16 h and 12 °C for 8 h) and low temperature (12 °C for 16 h and 6 °C for 8 h). Four genotypes were identified from the condition adapted gene pool with significant contrasting chilling tolerance. Picker and PR39B29 were the more cold-tolerant lines and Fergus and Codisco were the less cold-tolerant lines. These four varieties were subjected to microarray analysis to identify differentially expressed genes under chilling conditions. Exposure to low temperature during establishment in the maize varieties Picker, PR39B29, Fergus and Codisco, was reflected at the transcriptomic level in the varieties Picker and PR39B29. No significant changes in expression were observed in Fergus and Codisco following chilling stress. A total number of 64 genes were differentially expressed in the two chilling tolerant varieties. These two varieties exhibited contrasting transcriptomic profiles, in which only four genes overlapped. We observed that maize varieties possessing an enhanced root growth ratio under low temperature were more tolerant, which could be an early and inexpensive measure for germplasm screening under controlled conditions. We have identified novel cold inducible genes in an already adapted maize breeding gene pool. This illustrates that further varietal selection for enhanced chilling tolerance is possible in an already preselected gene pool.
Mauro Di Fenza
Full Text Available Background Maize (Zea mays is a C4 tropical cereal and its adaptation to temperate climates can be problematic due to low soil temperatures at early stages of establishment. Methods In the current study we have firstly investigated the physiological response of twelve maize varieties, from a chilling condition adapted gene pool, to sub-optimal growth temperature during seedling emergence. To identify transcriptomic markers of cold tolerance in already adapted maize genotypes, temperature conditions were set below the optimal growth range in both control and low temperature groups. The conditions were as follows; control (18 °C for 16 h and 12 °C for 8 h and low temperature (12 °C for 16 h and 6 °C for 8 h. Four genotypes were identified from the condition adapted gene pool with significant contrasting chilling tolerance. Results Picker and PR39B29 were the more cold-tolerant lines and Fergus and Codisco were the less cold-tolerant lines. These four varieties were subjected to microarray analysis to identify differentially expressed genes under chilling conditions. Exposure to low temperature during establishment in the maize varieties Picker, PR39B29, Fergus and Codisco, was reflected at the transcriptomic level in the varieties Picker and PR39B29. No significant changes in expression were observed in Fergus and Codisco following chilling stress. A total number of 64 genes were differentially expressed in the two chilling tolerant varieties. These two varieties exhibited contrasting transcriptomic profiles, in which only four genes overlapped. Discussion We observed that maize varieties possessing an enhanced root growth ratio under low temperature were more tolerant, which could be an early and inexpensive measure for germplasm screening under controlled conditions. We have identified novel cold inducible genes in an already adapted maize breeding gene pool. This illustrates that further varietal selection for enhanced chilling
Full Text Available Blast disease caused by Pyricularia oryzae is one of the limiting factors for rice production world wide. The use of resistant varieties for managing blast disease is considered as the most eco-friendly approaches. However, their resistances may be broken down within a few years due to the appearance of new virulent blast races in the field. The objective of the present study was to identify the quantitative trait locus (QTL conferring resistance to blast disease using 126 recombinant inbred (RI lines originated from a crossing of a durably resistant upland rice genotype (Laka and a highly susceptible rice accession cultivar (Kencana Bali. The RI population was developed through a single seed descent method from 1997 to 2004. Resistance of the RI lines was evaluated for blast in an endemic area of Sukabumi, West Java, in 2005. Disease intensity of the blast was examined following the standard evaluation system developed by the International Rice Research Institute (IRRI. At the same year the RI lines were analyzed with 134 DNA markers. Results of the study showed that one major QTL was found to be associated with blast resistance, and this QTL was located near RM2136 marker on the long arm of chromosome 11. This QTL explained 87% of the phenotypic variation with 37% additive effect. The map position of this QTL differed from that of a partial resistant gene, Pi34, identified previously on chromosome 11 in the Japanese durably resistant variety, Chubu 32. The QTL, however, was almost at the same position as that of the multiple allele-resistant gene, Pik. Therefore, an allelic test should be conducted to clarify the allelic relationship between QTL identified in this study and the Pik. The RI lines are the permanent segregating population that could be very useful for analysing phenotypic variations of important agronomic traits possibly owned by the RI lines. The major QTL identified in this study could be used as a genetic resource in
Kristen L. Kump
Full Text Available Data generated for initial quantitative trait loci (QTL mapping using recombinant inbred line (RIL populations are usually ignored during subsequent fine-mapping using near-isogenic lines (NILs. Combining both datasets would increase the number of recombination events sampled and generate better position and effect estimates. Previously, several QTL for resistance to southern leaf blight of maize were mapped in two RIL populations, each independently derived from a cross between the lines B73 and Mo17. In each case the largest QTL was in bin 3.04. Here, two NIL pairs differing for this QTL were derived and used to create two distinct F family populations that were assessed for southern leaf blight (SLB resistance. By accounting for segregation of the other QTL in the original RIL data, we were able to combine these data with the new genotypic and phenotypic data from the F families. Joint analysis yielded a narrower QTL support interval compared to that derived from analysis of any one of the data sets alone, resulting in the localization of the QTL to a less than 0.5 cM interval. Candidate genes identified within this interval are discussed. This methodology allows combined QTL analysis in which data from RIL populations is combined with data derived from NIL populations segregating for the same pair of alleles. It improves mapping resolution over the conventional approach with virtually no additional resources. Because data sets of this type are commonly produced, this approach is likely to prove widely applicable.
Martínez-Micaelo, Neus; González-Abuín, Noemi; Terra, Ximena; Ardévol, Ana; Pinent, Montserrat; Petretto, Enrico; Behmoaras, Jacques; Blay, Mayte
Obesity has reached pandemic levels worldwide. The current models of diet-induced obesity in rodents use predominantly high-fat based diets that do not take into account the consumption of variety of highly palatable, energy-dense foods that are prevalent in Western society. We and others have shown that the cafeteria (CAF) diet is a robust and reproducible model of human metabolic syndrome with tissue inflammation in the rat. We have previously shown that inbred rat strains such as Wistar Kyoto (WKY) and Lewis (LEW) show different susceptibilities to CAF diets with distinct metabolic and morphometric profiles. Here, we show a difference in plasma MCP-1 levels and investigate the effect of the CAF diet on peripheral blood monocyte transcriptome, as powerful stress-sensing immune cells, in WKY and LEW rats. We found that 75.5% of the differentially expressed transcripts under the CAF diet were upregulated in WKY rats and were functionally related to the activation of the immune response. Using a gene co-expression network constructed from the genes differentially expressed between CAF diet-fed LEW and WKY rats, we identified acyl-CoA synthetase short-chain family member 2 (Acss2) as a hub gene for a nutrient-sensing cluster of transcripts in monocytes. The Acss2 genomic region is significantly enriched for previously established metabolism quantitative trait loci in the rat. Notably, monocyte expression levels of Acss2 significantly correlated with plasma glucose, triglyceride, leptin and non-esterified fatty acid (NEFA) levels as well as morphometric measurements such as body weight and the total fat following feeding with the CAF diet in the rat. These results show the importance of the genetic background in nutritional genomics and identify inbred rat strains as potential models for CAF-diet-induced obesity. © 2016. Published by The Company of Biologists Ltd.
Full Text Available Obesity has reached pandemic levels worldwide. The current models of diet-induced obesity in rodents use predominantly high-fat based diets that do not take into account the consumption of variety of highly palatable, energy-dense foods that are prevalent in Western society. We and others have shown that the cafeteria (CAF diet is a robust and reproducible model of human metabolic syndrome with tissue inflammation in the rat. We have previously shown that inbred rat strains such as Wistar Kyoto (WKY and Lewis (LEW show different susceptibilities to CAF diets with distinct metabolic and morphometric profiles. Here, we show a difference in plasma MCP-1 levels and investigate the effect of the CAF diet on peripheral blood monocyte transcriptome, as powerful stress-sensing immune cells, in WKY and LEW rats. We found that 75.5% of the differentially expressed transcripts under the CAF diet were upregulated in WKY rats and were functionally related to the activation of the immune response. Using a gene co-expression network constructed from the genes differentially expressed between CAF diet-fed LEW and WKY rats, we identified acyl-CoA synthetase short-chain family member 2 (Acss2 as a hub gene for a nutrient-sensing cluster of transcripts in monocytes. The Acss2 genomic region is significantly enriched for previously established metabolism quantitative trait loci in the rat. Notably, monocyte expression levels of Acss2 significantly correlated with plasma glucose, triglyceride, leptin and non-esterified fatty acid (NEFA levels as well as morphometric measurements such as body weight and the total fat following feeding with the CAF diet in the rat. These results show the importance of the genetic background in nutritional genomics and identify inbred rat strains as potential models for CAF-diet-induced obesity.
Hoy, Yana Emmy; Bik, Elisabeth M; Lawley, Trevor D; Holmes, Susan P; Monack, Denise M; Theriot, Julie A; Relman, David A
Genetics, diet, and other environmental exposures are thought to be major factors in the development and composition of the intestinal microbiota of animals. However, the relative contributions of these factors in adult animals, as well as variation with time in a variety of important settings, are still not fully understood. We studied a population of inbred, female mice fed the same diet and housed under the same conditions. We collected fecal samples from 46 individual mice over two weeks, sampling four of these mice for periods as long as 236 days for a total of 190 samples, and determined the phylogenetic composition of their microbial communities after analyzing 1,849,990 high-quality pyrosequencing reads of the 16S rRNA gene V3 region. Even under these controlled conditions, we found significant inter-individual variation in community composition, as well as variation within an individual over time, including increases in alpha diversity during the first 2 months of co-habitation. Some variation was explained by mouse membership in different cage and vendor shipment groups. The differences among individual mice from the same shipment group and cage were still significant. Overall, we found that 23% of the variation in intestinal microbiota composition was explained by changes within the fecal microbiota of a mouse over time, 12% was explained by persistent differences among individual mice, 14% by cage, and 18% by shipment group. Our findings suggest that the microbiota of controlled populations of inbred laboratory animals may not be as uniform as previously thought, that animal rearing and handling may account for some variation, and that as yet unidentified factors may explain additional components of variation in the composition of the microbiota within populations and individuals over time. These findings have implications for the design and interpretation of experiments involving laboratory animals.
Full Text Available In plant breeding programs, it is often necessary to cross genotypes incompatible in time of flowering. In maize, when the incompatibility in flowering period could not be overcome by different sowing dates, or by the ability of silk to preserve its fertility in 10-15 days, conservation of pollen could be of great importance. For many plant species, the appropriate methods for pollen management have been set up, including methods of collecting, desiccation, testing of viability and longevity, as well as for pollen storage. The longevity of pollen during its storage depends upon plant species, conditions at the time of pollen collecting, pollen moisture content, as well as upon storage temperature and duration. Even within the same plant species, different genotypes exhibit different level of viability preservation during the conservation. Although maize pollen belongs to a tricellular pollen group and rapidly loses viability under field conditions, its preservation is possible. According to the literature, pollen viability could be preserved for 30 days in the conditions of refrigerator (+4°C, while in liquid nitrogen (-196°C up to 120 days. In the majority of studies, pollen viability was evaluated in the laboratory conditions, and the results obtained could largely be differed from those obtained under field conditions, due to impossibility to control a number of environmental factors. This experiment was conducted under field conditions in order to evaluate the ability of pollen from commercial maize inbred line L217, stored under the conditions of +4°C and -20°C, to pollinate maize inbred L73B013 and produce grain. Inbred L73B013 is sown in five sowing dates in order to ensure the longer presence of fresh silk. Pollen samples from line L217 were taken twice, and along with silica gel, stored in refrigerator and freezer. Each of successive pollination included five silks. Except for the expected good ear seed set when silks were
Hong, D.; Tian, Y.; Meng, X.; Zhang, P.
Arginase, as one of the three key enzymes in nitrogen catabolism, the physiological role of Arg catabolism in cereal crops has not been fully clarified. Studies have shown that arginase-encoding genes play a key role in providing nitrogen to developing seedlings in many plant species.Yield is a primary trait in many crop breeding programs, which can be increased by modification of genes related to photosynthesis, nitrogen assimilation, carbon distribution, plant architecture, and transcriptional networks controlling plant development. In the present study, a maize arginase gene ZmARG was cloned and introduced into maize inbred lines by Agrobacterium tumefaciens- mediated transformation. Putative transgenic plants were confirmed by PCR, Southern blotting RT-PCR analysis. The expression of the ZmARG gene increased arginase activity in several tissues in transgenic lines. Transgenic maize plants had significantly higher ear weight and 100-seed weight as compared with wild-type control. Our results suggested that ZmARG was a potential target gene for crop yield improvement. (author)
Zheng, Z P; Liu, X H
Maize (Zea mays L.) is one of the most important cereal crops worldwide, and increasing the grain yield and biomass has been among the most important goals of maize production. The plant architecture can determine the grain yield and biomass to some extent; however, the genetic basis of the link between the plant architecture and grain yield/biomass is unclear. In this study, an immortal F9 recombinant inbred line population, derived from the cross Mo17 x Huangzao4, was used to detect quantitative trait loci (QTLs) for 3 traits associated with plant architecture under two nitrogen regimes: plant height, ear height, and leaf number. As a result, 8 and 10 QTLs were identified under the high nitrogen regime and low nitrogen regime, respectively. These QTLs mapped to chromosomes 1 (six QTLs), 2 (one QTL), 3 (one QTL), 7 (two QTLs), and 9 (eight QTLs), and had different genetic distances to their closest markers, ranging from 0 to 22.0 cM, explaining 4.7 to 20.5% of the phenotypic variance. Because of an additive effect, 9 and 9 could make the phenotypic values of traits increase and decrease to some extent, respectively. These results are beneficial for understanding the genetic basis of agronomic traits associated with plant architecture and for performing marker-assisted selection in maize breeding programs.
Dou, Yao; Liu, Xiangguo; Yin, Yuejia; Han, Siping; Lu, Yang; Liu, Yang; Hao, Dongyun
The 14-3-3 proteins are a group of regulatory proteins of divergent functions in plants. However, little is known about their roles in maize kernel development. Using publically available gene expression profiling data, we found that two 14-3-3 species genes, zmgf14-4 and zmgf14-6, exhibited prominent expression profiles over other 14-3-3 protein genes during maize kernel development. More than 5000 transcripts of these two genes were identified accounting for about 1/10 of the total transcripts of genes correlating to maize kernel development. We constructed a proteomics pipeline based on the affinity chromatography, in combination with 2-DE and LC-MS/MS technologies to identify the specific client proteins of the two proteins for their functional characterization. Consequently, we identified 77 specific client proteins from the developing kernels of the inbred maize B73. More than 60% of the client proteins were commonly affinity-identified by the two 14-3-3 species and are predicted to be implicated in the fundamental functions of metabolism, protein destination and storage. In addition, we found ZmGF14-4 specifically bound to the disease- or defense-relating proteins, whilst ZmGF14-6 tended to interact with the proteins involving metabolism and cell structure. Our findings provide primary insights into the functional roles of 14-3-3 proteins in maize kernel development. Maize kernel development is a complicated physiological process for its importance in both genetics and cereal breeding. 14-3-3 proteins form a multi-gene family participating in regulations of developmental processes in plants. However, the correlation between this protein family and maize kernel development has hardly been studied. We have for the first time found 12 14-3-3 protein genes from maize genome and studied in silico the gene transcription profiling of these genes. Comparative studies revealed that maize kernel development aroused a great number of gene expression, among which 14
Steenekamp, Willem Abraham Jacobus
The first Roundup Ready crop to be commercialised was soybean in 1996. Soybean farmers, initially in the USA and more recently in Argentina, rapidly accepted these varieties. Roundup Ready soybeans were commercialised in South Africa in 1999. Since then Roundup Ready maize, canola and cotton have also been induced in the USA. The introduction of Roundup Ready technology may be viewed as a disruptive technology. This innovative technology emerged 25 years after the discovery of the...
Toric varieties associated with distributive lattices arise as a fibre of a flat degeneration of a Schubert variety in a minuscule. The singular locus of these varieties has been studied by various authors. In this article we prove that the number of diamonds incident on a lattice point $\\a$ in a product of chain lattices is more than or equal to the codimension of the lattice. Using this we also show that the lattice varieties associated with product of chain lattices is smooth.
Ferreira, Carla; Veiga, Adelcia; Puga, João; Kikuchi, Ryunosuke; Ferreira, António
Land degradation in agricultural areas is a major concern. The large number of mechanical interventions and the amount of inputs used to assure high crop productivity, such as fertilizers and pesticides, have negative impacts on soil quality and threaten crop productivity and environmental sustainability. Organic farming is an alternative agriculture system, based on organic fertilizers, biological pest control and crop rotation, in order to mitigate soil degradation. Maize is the third most important cereal worldwide, with 2008 million tons produced in 2013 (IGN, 2016). In Portugal, 120000 ha of arable land is devoted to maize production, leading to annual yields of about 930000 ton (INE, 2015). This study investigates soil quality differences in maize farms under organic and conventional systems. The study was carried out in Coimbra Agrarian Technical School (ESAC), in central region of Portugal. ESAC campus comprises maize fields managed under conventional farming - Vagem Grande (32 ha), and organic fields - Caldeirão (12 ha), distancing 2.8 km. Vagem Grande has been intensively used for grain maize production for more than 20 years, whereas Caldeirão was converted to organic farming in 2008, and is being used to select regional maize varieties. The region has a Mediterranean climate. The maize fields have Eutric Fluvisols, with gentle slopes (20cm), using mustard solution.
Tesfaye, Kindie; Zaidi, P. H.; Gbegbelegbe, Sika; Boeber, Christian; Rahut, Dil Bahadur; Getaneh, Fite; Seetharam, K.; Erenstein, Olaf; Stirling, Clare
Maize is grown by millions of smallholder farmers in South Asia (SA) under diverse environments. The crop is grown in different seasons in a year with varying exposure to weather extremes, including high temperatures at critical growth stages which are expected to increase with climate change. This study assesses the impact of current and future heat stress on maize and the benefit of heat-tolerant varieties in SA. Annual mean maximum temperatures may increase by 1.4-1.8 °C in 2030 and 2.1-2.6 °C in 2050, with large monthly, seasonal, and spatial variations across SA. The extent of heat stressed areas in SA could increase by up to 12 % in 2030 and 21 % in 2050 relative to the baseline. The impact of heat stress and the benefit from heat-tolerant varieties vary with the level of temperature increase and planting season. At a regional scale, climate change would reduce rainfed maize yield by an average of 3.3-6.4 % in 2030 and 5.2-12.2 % in 2050 and irrigated yield by 3-8 % in 2030 and 5-14 % in 2050 if current varieties were grown under the future climate. Under projected climate, heat-tolerant varieties could minimize yield loss (relative to current maize varieties) by up to 36 and 93 % in 2030 and 33 and 86 % in 2050 under rainfed and irrigated conditions, respectively. Heat-tolerant maize varieties, therefore, have the potential to shield maize farmers from severe yield loss due to heat stress and help them adapt to climate change impacts.
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.
Full Text Available In the area, there are no selected maize materials for forage production, tall and long-cycle creole maize varieties are used, there are overturning problems that make management difficult. The study was conducted in the dairy highlands of Costa Rica at an altitude of 2200 m, between 2008 and 2009. This study was made in order to compare the forage production and the nutritive value of nine maize hybrids (Zea mays with local oats (Avena sativa in a randomized design of complete blocks and three replicates. Harvesting took place at grain stage called milky-doughy (4 and 6.5 months for oats and maize hybrids. Oats had a dry matter yield (14 t/ha and dry matter digestibility (8.7 t/ha higher (P<0.0001 than hybrids (7.8 and 4.9, respectively. Although hybrids showed a higher (p<0.05 percentage of dry matter (mean 19.2 and in vitro dry matter digestibility (mean 63.2, oats had percentages of 16.7 and 61.9 within the same order. The percentage of crude protein in oats (14.2 was higher (p <0.05 than maize hybrids (mean 10.9. The creole oat variety showed a higher forage resource than the evaluated hybrid maize.
Li, Yuling; Wang, Yanzhao; Wei, Mengguan; Li, Xuehui; Fu, Jiafeng
Protein is one of the three main storage chemical components in maize grains, and is negatively correlated with starch concentration (SC). Our objective was to analyse the influence of genetic backgrounds on QTL detection for protein concentration (PC) and to reveal the molecular genetic associations between PC and both SC and grain weight (GWP). Two hundred and eighty-four (Pop1) and 265 (Pop2) F(2:3) families were developed from two crosses between one high-oil maize inbred GY220 and two normal maize inbreds 8984 and 8622 respectively, and were genotyped with 185 and 173 pairs of SSR markers. PC, SC and GWP were evaluated under two environments. Composite interval mapping (CIM) and multiple interval mapping (MIM) methods were used to detect single-trait QTL for PC, and multiple-trait QTL for PC with both SC and GWP. No common QTL were shared between the two populations for their four and one PC QTL. Common QTL with opposite signs of effects for PC and SCGWP were detected on three marker intervals at bins 6.07-6.08, 8.03 and 8.03-8.04. Multiple-traits QTL mapping showed that tightly-linked QTL, pleiotropic QTL and QTL having effects with opposite directions for PC and SCGWP were all observed in Pop1, while all QTL reflected opposite effects in Pop2.
Tao, Yongfu; Jiang, Lu; Liu, Qingqing; Zhang, Yan; Zhang, Rui; Ingvardsen, Christina Roenn; Frei, Ursula Karoline; Wang, Baobao; Lai, Jinsheng; Lübberstedt, Thomas; Xu, Mingliang
Sugarcane mosaic virus (SCMV) disease causes substantial losses of grain yield and forage biomass in susceptible maize cultivars. Maize resistance to SCMV is associated with two dominant genes, Scmv1 and Scmv2, which are located on the short arm of chromosome 6 and near the centromere region of chromosome 3, respectively. We combined both linkage and association mapping to identify positional candidate genes for Scmv1. Scmv1 was fine-mapped in a segregating population derived from near-isogenic lines and further validated and fine-mapped using two recombinant inbred line populations. The combined results assigned the Scmv1 locus to a 59.21-kb interval, and candidate genes within this region were predicted based on the publicly available B73 sequence. None of three predicted genes that are possibly involved in the disease resistance response are similar to receptor-like resistance genes. Candidate gene-based association mapping was conducted using a panel of 94 inbred lines with variable resistance to SCMV. A presence/absence variation (PAV) in the Scmv1 region and two polymorphic sites around the Zmtrx-h gene were significantly associated with SCMV resistance. Combined linkage and association mapping pinpoints Zmtrx-h as the most likely positional candidate gene for Scmv1. These results pave the way towards cloning of Scmv1 and facilitate marker-assisted selection for potyvirus resistance in maize.
Barros, E.; Lezar, S.; Anttonen, M.J.; Dijk, van J.P.; Rohlig, R.M.; Kok, E.J.; Engel, K.H.
P>The aim of this study was to evaluate the use of four nontargeted analytical methodologies in the detection of unintended effects that could be derived during genetic manipulation of crops. Three profiling technologies were used to compare the transcriptome, proteome and metabolome of two
Chotewutmontri, Prakitchai; Stiffler, Nicholas; Watkins, Kenneth P; Barkan, Alice
Ribosome profiling (also known as Ribo-seq) provides a genome-wide, high-resolution, and quantitative accounting of mRNA segments that are occupied by ribosomes in vivo. The method has been used to address numerous questions in bacteria, yeast, and metazoa, but its application to questions in plant biology is just beginning. This chapter provides a detailed protocol for profiling ribosomes in plant leaf tissue. The method was developed and optimized with maize, but it has been used successfully with Arabidopsis and tobacco as well. The method captures ribosome footprints from the chloroplast and cytosol in the same preparation, but it is not optimal for detecting the footprints of mitochondrial ribosomes. The protocol is robust and simpler than many of the methods reported previously for ribosome profiling in plants.
Tao, Yongfu; Liu, Qingcai; Wang, Honghong; Zhang, Yanjun; Huang, Xinyi; Wang, Baobao; Lai, Jinsheng; Ye, Jianrong; Liu, Baoshen; Xu, Mingliang
Maize rough dwarf disease (MRDD) is a devastating viral disease that results in considerable yield losses worldwide. Three major strains of virus cause MRDD, including maize rough dwarf virus in Europe, Mal de Río Cuarto virus in South America, and rice black-streaked dwarf virus in East Asia. These viral pathogens belong to the genus fijivirus in the family Reoviridae. Resistance against MRDD is a complex trait that involves a number of quantitative trait loci (QTL). The primary approach used to minimize yield losses from these viruses is to breed and deploy resistant maize hybrids. Of the 50 heterogeneous inbred families (HIFs), 24 showed consistent responses to MRDD across different years and locations, in which 9 were resistant and 15 were susceptible. We performed trait-marker association analysis on the 24 HIFs and found six chromosomal regions which were putatively associated with MRDD resistance. We then conducted QTL analysis and detected a major resistance QTL, qMrdd1, on chromosome 8. By applying recombinant-derived progeny testing to self-pollinated backcrossed families, we fine-mapped the qMrdd1 locus into a 1.2-Mb region flanked by markers M103-4 and M105-3. The qMrdd1 locus acted in a recessive manner to reduce the disease-severity index (DSI) by 24.2-39.3%. The genetic effect of qMrdd1 was validated using another F6 recombinant inbred line (RIL) population in which MRDD resistance was segregating and two genotypes at the qMrdd1 locus differed significantly in DSI values. The qMrdd1 locus is a major resistance QTL, acting in a recessive manner to increase maize resistance to MRDD. We mapped qMrdd1 to a 1.2-Mb region, which will enable the introgression of qMrdd1-based resistance into elite maize hybrids and reduce MRDD-related crop losses.
Ma, Wei; Muthreich, Nils; Liao, Chengsong; Franz-Wachtel, Mirita; Schütz, Wolfgang; Zhang, Fusuo; Hochholdinger, Frank; Li, Chunjian
Maize (Zea mays L.) root cap cells secrete a large variety of compounds including proteins via an amorphous gel structure called mucilage into the rhizosphere. In the present study, mucilage secreted by primary roots of 3-4 day old maize seedlings was collected under axenic conditions, and the constitutively secreted proteome was analyzed. A total of 2848 distinct extracellular proteins were identified by nanoLC-MS/MS. Among those, metabolic proteins (approximately 25%) represented the largest class of annotated proteins. Comprehensive sets of proteins involved in cell wall metabolism, scavenging of reactive oxygen species, stress response, or nutrient acquisition provided detailed insights in functions required at the root-soil interface. For 85-94% of the mucilage proteins previously identified in the relatively small data sets of the dicot species pea, Arabidopsis, and rapeseed, a close homologue was identified in the mucilage proteome of the monocot model plant maize, suggesting a considerable degree of conservation between mono and dicot mucilage proteomes. Homologues of a core set of 12 maize proteins including three superoxide dismutases and four chitinases, which provide protection from fungal infections, were present in all three mucilage proteomes investigated thus far in the dicot species Arabidopsis, rapeseed, and pea and might therefore be of particular importance.
Full Text Available Seed aging decreases the quality and vigor of crop seeds, thereby causing substantial agricultural and economic losses in crops. To identify genetic differences in seed aging between homozygotes and heterozygotes in maize, the seeds of a set of recombinant inbred lines (RILs and an immortalized F2 (IF2 population were subjected to artificial aging treatments for 0, 2, 3, and 4 days under 45 ºC and 85% relative humidity and seed vigor was then evaluated in a field experiment. Seed vigor of all entries tested decreased sharply with longer aging treatment and seed vigor decreased more slowly in heterozygotes than in homozygotes. Forty-nine QTL were detected for four measured seed vigor traits in the RIL (28 QTL and IF2 (21 QTL populations. Only one QTL, qGP5, was detected in both populations, indicating that the genes involved in anti-aging mechanisms differed between inbred lines and hybrids. Several QTL were identified to be responsible for multiple seed vigor traits simultaneously in the RIL and IF2 populations under artificial aging conditions. These QTL may include major genes for seed vigor or seed aging. QTL qVI4b and qGE3a detected in the RIL population coincided with genes ZmLOX1 and ZmPLD1 in the same respective chromosomal regions. These QTL would be useful for screening for anti-aging genes in maize breeding.
Full Text Available An understanding of the genetic determinism of photoperiod response of flowering is a prerequisite for the successful exchange of germplasm across different latitudes. In order to contribute to resolve the genetic basis of photoperiod sensitivity in maize, a set of 201 recombinant inbred lines (RIL, derived from a temperate and tropical inbred line cross were evaluated in 5 field trials spread in short- and long-day environments.Firstly, QTL analyses for flowering time and photoperiod sensitivity in maize were conducted in individual photoperiod environments separately, and then, the total genetic effect was partitioned into additive effect (A and additive-by-environment interaction effect (AE by using a mixed-model-based composite interval mapping (MCIM method.Seven putative QTL were found associated with DPS thermal time based on the data estimated in individual environments. Nine putative QTL were found associated with DPS thermal time across environments and six of them showed significant QTL×enviroment (QE interactions. Three QTL for photoperiod sensitivity were identified on chromosome 4, 9 and 10, which had the similar position to QTL for DPS thermal time in the two long-day environment. The major photoperiod sensitive loci qDPS10 responded to both short and long-day photoperiod environments and had opposite effects in different photoperiod environment. The QTL qDPS3, which had the greatest additive effect exclusively in the short-day environment, were photoperiod independent and should be classified in autonomous promotion pathway.
Full Text Available Increasing grain yield by the selection for optimal plant architecture has been the key focus in modern maize breeding. As a result, leaf angle, an important determinant of plant architecture, has been significantly improved to adapt to the ever-increasing plant density in maize production over the past several decades. To extend our understanding on the genetic mechanisms of leaf angle in maize, we developed the first four-way cross mapping population, consisting of 277 lines derived from four maize inbred lines with varied leaf angles. The four-way cross mapping population together with the four parental lines were evaluated for leaf angle in two environments. In this study, we reported linkage maps built in the population and quantitative trait loci (QTL on leaf angle detected by inclusive composite interval mapping (ICIM. ICIM applies a two-step strategy to effectively separate the cofactor selection from the interval mapping, which controls the background additive and dominant effects at the same time. A total of 14 leaf angle QTL were identified, four of which were further validated in near-isogenic lines (NILs. Seven of the 14 leaf angle QTL were found to overlap with the published leaf angle QTL or genes, and the remaining QTL were unique to the four-way population. This study represents the first example of QTL mapping using a four-way cross population in maize, and demonstrates that the use of specially designed four-way cross is effective in uncovering the basis of complex and polygenetic trait like leaf angle in maize.
Mano, Y.; Omori, F.
Background and Aims Nicaraguan teosinte (Zea nicaraguensis), a species found in frequently flooded areas, provides useful germplasm for breeding flooding-tolerant maize (Z. mays subsp. mays). The objective of this study was to select flooding-tolerant lines using a library of introgression lines (ILs), each containing a chromosome segment from Z. nicaraguensis in the maize inbred line Mi29. Methods To produce the ILs, a single F1 plant derived from a cross between maize Mi29 and Z. nicaraguensis was backcrossed to Mi29 three times, self-pollinated four times and genotyped using simple sequence repeat markers. Flooding tolerance was evaluated at the seedling stage under reducing soil conditions. Key Results By backcrossing and selfing, a series of 45 ILs were developed covering nearly the entire maize genome. Five flooding-tolerant lines were identified from among the ILs by evaluating leaf injury. Among these, line IL#18, containing a Z. nicaraguensis chromosome segment on the long arm of chromosome 4, showed the greatest tolerance to flooding, suggesting the presence of a major quantitative trait locus (QTL) in that region. The presence of the QTL was verified by examining flooding tolerance in a population segregating for the candidate region of chromosome 4. There was no significant relationship between the capacity to form constitutive aerenchyma and flooding tolerance in the ILs, indicating the presence of other factors related to flooding tolerance under reducing soil conditions. Conclusions A flooding-tolerant genotype, IL#18, was identified; this genotype should be useful for maize breeding. In addition, because the chromosome segments of Z. nicaraguensis in the ILs cover nearly the entire genome and Z. nicaraguensis possesses several unique traits related to flooding tolerance, the ILs should be valuable material for additional QTL detection and the development of flooding-tolerant maize lines. PMID:23877074
Full Text Available Intercropping systems could improve utilization of the most important resources (soil, water and nutrients, provide a better control of weeds, pests and diseases, and finally higher productivity, especially under rain-fed growing conditions. This study aimed to determine the effects of three maize (Zea mays L. prolific hybrids (FAO 500, 600 and 700 and the spatial intercrop patterns on the above-ground biomass and grain yields of maize and soybean (Glycine max L. Merrill, on chernozem soil type at Zemun Polje, Belgrade, in 2003, 2004 and 2005. The experimental design was a complete randomized block with four replications and three treatments: 3 rows of maize and 3 rows of soybean in strips for each maize hybrid (three variants, 3 rows of maize and 3 rows of soybean in alternate rows for each hybrid (another three variants and monocrops of both maize and soybeans. To optimize the ecological and economic benefits of maize/soybean intercrop in terms of yield, variety selection and compatibility of the component crops should be made using established agronomic management practices involving the two crops. Suitable maize varieties for maize/soybean intercrop systems are varieties that have less dense canopy. These varieties would therefore have lesser shading effect to the understory beans. However, establishment of an appropriate spatial arrangement of the component crops would be essential to alleviate negative effects especially on the less competitive crop. The intercropping system in alternate rows showed significantly higher above-ground biomass and grain yields in comparation with both the strip intercropping system and maize monocrops in 2004. Soybean gave significantly lower above-ground biomass and grain yield in intercrops than in monocrops. Maize prolific hybrid growing in intercropping with soybean as legume crop, increased productivity of cropping system, especially in favourable agroecological conditions. Maize and soybean yields
Hindu, Vemuri; Palacios-Rojas, Natalia; Babu, Raman; Suwarno, Willy B; Rashid, Zerka; Usha, Rayalcheruvu; Saykhedkar, Gajanan R; Nair, Sudha K
Genome-wide association study (GWAS) on 923 maize lines and validation in bi-parental populations identified significant genomic regions for kernel-Zinc and-Iron in maize. Bio-fortification of maize with elevated Zinc (Zn) and Iron (Fe) holds considerable promise for alleviating under-nutrition among the world's poor. Bio-fortification through molecular breeding could be an economical strategy for developing nutritious maize, and hence in this study, we adopted GWAS to identify markers associated with high kernel-Zn and Fe in maize and subsequently validated marker-trait associations in independent bi-parental populations. For GWAS, we evaluated a diverse maize association mapping panel of 923 inbred lines across three environments and detected trait associations using high-density Single nucleotide polymorphism (SNPs) obtained through genotyping-by-sequencing. Phenotyping trials of the GWAS panel showed high heritability and moderate correlation between kernel-Zn and Fe concentrations. GWAS revealed a total of 46 SNPs (Zn-20 and Fe-26) significantly associated (P ≤ 5.03 × 10 -05 ) with kernel-Zn and Fe concentrations with some of these associated SNPs located within previously reported QTL intervals for these traits. Three double-haploid (DH) populations were developed using lines identified from the panel that were contrasting for these micronutrients. The DH populations were phenotyped at two environments and were used for validating significant SNPs (P ≤ 1 × 10 -03 ) based on single marker QTL analysis. Based on this analysis, 11 (Zn) and 11 (Fe) SNPs were found to have significant effect on the trait variance (P ≤ 0.01, R 2 ≥ 0.05) in at least one bi-parental population. These findings are being pursued in the kernel-Zn and Fe breeding program, and could hold great value in functional analysis and possible cloning of high-value genes for these traits in maize.
Full Text Available The western highlands of Guatemala lie within the area where maize was first domesticated, and maize remains central to farmers' livelihood security. Over 50% of the population in the region are in poverty, and over 48% suffer from chronic malnutrition. Development efforts have focused on improved land management, crop diversification, and improved access to markets, especially for high-value vegetable crops such as snow peas. As a result of successful initiatives worldwide, more attention is being directed at the extent to which farmers can benefit from market opportunities for indigenous crops by receiving a price premium for providing the environmental service of conserving agricultural biodiversity. Such an approach bridges the gap between poverty alleviation and in situ conservation. We explored this potential development pathway through both qualitative and quantitative research. Focus groups were conducted in 5 communities in the maize-growing highlands of Guatemala, followed by a survey of 989 farm households in 59 locations. Our results show that most farmers in the western highlands of Guatemala are severely maize deficient; on average, farm households produce enough maize for only 6.9 months of consumption a year and are forced to purchase maize to meet basic consumption needs. The results are in sharp contrast to research conducted in highland communities in neighboring Mexico, where many farmers are able to sell their maize in relatively lucrative specialty maize markets. In the context of renewed interest in reducing poverty in Central America, our research suggests that rather than focus on market development for local maize varieties, development efforts should target other types of interventions.
Bilska-Kos, Anna; Solecka, Danuta; Dziewulska, Aleksandra; Ochodzki, Piotr; Jończyk, Maciej; Bilski, Henryk; Sowiński, Paweł
The cell wall emerged as one of the important structures in plant stress responses. To investigate the effect of cold on the cell wall properties, the content and localization of pectins and pectin methylesterase (PME) activity, were studied in two maize inbred lines characterized by different sensitivity to cold. Low temperature (14/12 °C) caused a reduction of pectin content and PME activity in leaves of chilling-sensitive maize line, especially after prolonged treatment (28 h and 7 days). Furthermore, immunocytohistological studies, using JIM5 and JIM7 antibodies, revealed a decrease of labeling of both low- and high-methylesterified pectins in this maize line. The osmotic potential, quantified by means of incipient plasmolysis was lower in several types of cells of chilling-sensitive maize line which was correlated with the accumulation of sucrose. These studies present new finding on the effect of cold stress on the cell wall properties in conjunction with changes in the osmotic potential of maize leaf cells.
van Heerwaarden, Joost; Hellin, J; Visser, R F; van Eeuwijk, F A
Replacement of crop landraces by modern varieties is thought to cause diversity loss. We studied genetic erosion in maize within a model system; modernized smallholder agriculture in southern Mexico. The local seed supply was described through interviews and in situ seed collection. In spite of the dominance of commercial seed, the informal seed system was found to persist. True landraces were rare and most informal seed was derived from modern varieties (creolized). Seed lots were characterized for agronomical traits and molecular markers. We avoided the problem of non-consistent nomenclature by taking individual seed lots as the basis for diversity inference. We defined diversity as the weighted average distance between seed lots. Diversity was calculated for subsets of the seed supply to assess the impact of replacing traditional landraces with any of these subsets. Results were different for molecular markers, ear- and vegetative/flowering traits. Nonetheless, creolized varieties showed low diversity for all traits. These varieties were distinct from traditional landraces and little differentiated from their ancestral stocks. Although adoption of creolized maize into the informal seed system has lowered diversity as compared to traditional landraces, genetic erosion was moderated by the distinct features offered by modern varieties.
Hendriksma, Harmen P; Küting, Meike; Härtel, Stephan; Näther, Astrid; Dohrmann, Anja B; Steffan-Dewenter, Ingolf; Tebbe, Christoph C
Honey bee pollination is a key ecosystem service to nature and agriculture. However, biosafety research on genetically modified crops rarely considers effects on nurse bees from intact colonies, even though they receive and primarily process the largest amount of pollen. The objective of this study was to analyze the response of nurse bees and their gut bacteria to pollen from Bt maize expressing three different insecticidal Cry proteins (Cry1A.105, Cry2Ab2, and Cry3Bb1). Naturally Cry proteins are produced by bacteria (Bacillus thuringiensis). Colonies of Apis mellifera carnica were kept during anthesis in flight cages on field plots with the Bt maize, two different conventionally bred maize varieties, and without cages, 1-km outside of the experimental maize field to allow ad libitum foraging to mixed pollen sources. During their 10-days life span, the consumption of Bt maize pollen had no effect on their survival rate, body weight and rates of pollen digestion compared to the conventional maize varieties. As indicated by ELISA-quantification of Cry1A.105 and Cry3Bb1, more than 98% of the recombinant proteins were degraded. Bacterial population sizes in the gut were not affected by the genetic modification. Bt-maize, conventional varieties and mixed pollen sources selected for significantly different bacterial communities which were, however, composed of the same dominant members, including Proteobacteria in the midgut and Lactobacillus sp. and Bifidobacterium sp. in the hindgut. Surprisingly, Cry proteins from natural sources, most likely B. thuringiensis, were detected in bees with no exposure to Bt maize. The natural occurrence of Cry proteins and the lack of detectable effects on nurse bees and their gut bacteria give no indication for harmful effects of this Bt maize on nurse honey bees.
Harmen P Hendriksma
Full Text Available Honey bee pollination is a key ecosystem service to nature and agriculture. However, biosafety research on genetically modified crops rarely considers effects on nurse bees from intact colonies, even though they receive and primarily process the largest amount of pollen. The objective of this study was to analyze the response of nurse bees and their gut bacteria to pollen from Bt maize expressing three different insecticidal Cry proteins (Cry1A.105, Cry2Ab2, and Cry3Bb1. Naturally Cry proteins are produced by bacteria (Bacillus thuringiensis. Colonies of Apis mellifera carnica were kept during anthesis in flight cages on field plots with the Bt maize, two different conventionally bred maize varieties, and without cages, 1-km outside of the experimental maize field to allow ad libitum foraging to mixed pollen sources. During their 10-days life span, the consumption of Bt maize pollen had no effect on their survival rate, body weight and rates of pollen digestion compared to the conventional maize varieties. As indicated by ELISA-quantification of Cry1A.105 and Cry3Bb1, more than 98% of the recombinant proteins were degraded. Bacterial population sizes in the gut were not affected by the genetic modification. Bt-maize, conventional varieties and mixed pollen sources selected for significantly different bacterial communities which were, however, composed of the same dominant members, including Proteobacteria in the midgut and Lactobacillus sp. and Bifidobacterium sp. in the hindgut. Surprisingly, Cry proteins from natural sources, most likely B. thuringiensis, were detected in bees with no exposure to Bt maize. The natural occurrence of Cry proteins and the lack of detectable effects on nurse bees and their gut bacteria give no indication for harmful effects of this Bt maize on nurse honey bees.
Aug 8, 2011 ... Ear axis weight (EAW) is one of the important agronomic traits in maize (Zea mays L.), related to yield. To understand its genetic ... but the studies on using different N environments to map. QTL for maize EAW were not .... Mapping QTLs for grain yield and yield components under high and low phosphorus ...
Ma, Yu-ping; Sun, Lin-li; E, You-hao; Wu, Wei
Climate change will significantly affect agricultural production in China. The combination of the integral regression model and the latest climate projection may well assess the impact of future climate change on crop yield. In this paper, the correlation model of maize yield and meteorological factors was firstly established for different provinces in China by using the integral regression method, then the impact of climate change in the next 40 years on China's maize production was evaluated combined the latest climate prediction with the reason be ing analyzed. The results showed that if the current speeds of maize variety improvement and science and technology development were constant, maize yield in China would be mainly in an increasing trend of reduction with time in the next 40 years in a range generally within 5%. Under A2 climate change scenario, the region with the most reduction of maize yield would be the Northeast except during 2021-2030, and the reduction would be generally in the range of 2.3%-4.2%. Maize yield reduction would be also high in the Northwest, Southwest and middle and lower reaches of Yangtze River after 2031. Under B2 scenario, the reduction of 5.3% in the Northeast in 2031-2040 would be the greatest across all regions. Other regions with considerable maize yield reduction would be mainly in the Northwest and the Southwest. Reduction in maize yield in North China would be small, generally within 2%, under any scenarios, and that in South China would be almost unchanged. The reduction of maize yield in most regions would be greater under A2 scenario than under B2 scenario except for the period of 2021-2030. The effect of the ten day precipitation on maize yield in northern China would be almost positive. However, the effect of ten day average temperature on yield of maize in all regions would be generally negative. The main reason of maize yield reduction was temperature increase in most provinces but precipitation decrease in a few
Jaramillo, Raúl E; Nord, Eric A; Chimungu, Joseph G; Brown, Kathleen M; Lynch, Jonathan P
Root cortical aerenchyma (RCA) increases water and nutrient acquisition by reducing the metabolic costs of soil exploration. In this study the hypothesis was tested that living cortical area (LCA; transversal root cortical area minus aerenchyma area and intercellular air space) is a better predictor of root respiration, soil exploration and, therefore, drought tolerance than RCA formation or root diameter. RCA, LCA, root respiration, root length and biomass loss in response to drought were evaluated in maize (Zea mays) recombinant inbred lines grown with adequate and suboptimal irrigation in soil mesocosms. Root respiration was highly correlated with LCA. LCA was a better predictor of root respiration than either RCA or root diameter. RCA reduced respiration of large-diameter roots. Since RCA and LCA varied in different parts of the root system, the effects of RCA and LCA on root length were complex. Greater crown-root LCA was associated with reduced crown-root length relative to total root length. Reduced LCA was associated with improved drought tolerance. The results are consistent with the hypothesis that LCA is a driver of root metabolic costs and may therefore have adaptive significance for water acquisition in drying soil.
Full Text Available The objective of this study was to evaluate following parameters of the ear length of silage maize: variability of inbred lines and their diallel hybrids, superior-parent heterosis and genetic components of variability and habitability on the basis of a diallel set. The analysis of genetic variance shows that the additive component (D was lower than the dominant (H1 and H2 genetic variances, while the frequency of dominant genes (u for this trait was greater than the frequency of recessive genes (v Furthermore, this is also confirmed by the dominant to recessive genes ratio in parental inbreeds for the ear length (Kd/Kr> 1, which is greater than unity during both investigation years. The calculated value of the average degree of dominance √H1/D is greater than unity, pointing out to superdominance in inheritance of this trait in both years of investigation, which is also confirmed by the results of Vr/Wr regression analysis of inheritance of the ear length. As a presence of the non-allelic interaction was established it is necessary to study effects of epitasis as it can have a greater significance in certain hybrids. A greater value of dominant than additive variance resulted in high broad-sense habitability for ear length in both investigation years.
Full Text Available BACKGROUND: Bt-maize is a transgenic variety of maize expressing the Cry toxin from Bacillus turingiensis. The potential accumulation of the relative effect of the transgenic modification and the cry toxin on the rhizobacterial communities of Bt-maize has been monitored over a period of four years. METHODOLOGY/PRINCIPAL FINDINGS: The accumulative effects of the cultivation of this transgenic plant have been monitored by means of high throughput DNA pyrosequencing of the bacterial DNA coding for the 16S rRNA hypervariable V6 region from rhizobacterial communities. The obtained sequences were subjected to taxonomic, phylogenetic and taxonomic-independent diversity studies. The results obtained were consistent, indicating that variations detected in the rhizobacterial community structure were possibly due to climatic factors rather than to the presence of the Bt-gene. No variations were observed in the diversity estimates between non-Bt and Bt-maize. CONCLUSIONS/SIGNIFICANCE: The cultivation of Bt-maize during the four-year period did not change the maize rhizobacterial communities when compared to those of the non-Bt maize. This is the first study to be conducted with Bt-maize during such a long cultivation period and the first evaluation of rhizobacterial communities to be performed in this transgenic plant using Next Generation Sequencing.
Ligeyo, D.O.; Ayiecho, P.O.
Estimates of mean, additive, dominance, additive * additive, additive * dominance and dominance * dominance genetic effects were obtained for six crosses from four inbred lines of maize for grain yield. All the genetic effects contributed to the inheritance of yield. However not all genetic effects are present in all crosses at all locations. Both additive dominance genetic effects were responsible for the manifestation variability in grain yield, though the dominance genetic effect was preponderant in all cases. In most cases additive * additive and additive * dominance effects were more important contributors to inheritance than dominance * dominance gene effects at all locations.In all cases the manifestation of various genetic effects varied according to crosses and experimental sites
Gayral, Mathieu; Bakan, Bénédicte; Dalgalarrondo, Michele; Elmorjani, Khalil; Delluc, Caroline; Brunet, Sylvie; Linossier, Laurent; Morel, Marie-Hélène; Marion, Didier
Content and composition of maize endosperm lipids and their partition in the floury and vitreous regions were determined for a set of inbred lines. Neutral lipids, i.e., triglycerides and free fatty acids, accounted for more than 80% of endosperm lipids and are almost 2 times higher in the floury than in the vitreous regions. The composition of endosperm lipids, including their fatty acid unsaturation levels, as well as their distribution may be related to metabolic specificities of the floury and vitreous regions in carbon and nitrogen storage and to the management of stress responses during endosperm cell development. Remarkably, the highest contents of starch lipids were observed systematically within the vitreous endosperm. These high amounts of starch lipids were mainly due to lysophosphatidylcholine and were tightly linked to the highest amylose content. Consequently, the formation of amylose-lysophosphatidylcholine complexes has to be considered as an outstanding mechanism affecting endosperm vitreousness.
Zhang, Zhi-Yong; Yang, Lin; Zhou, Shu-Feng; Wang, Han-Guang; Li, Wan-Chen; Fu, Feng-Ling
To overcome the low efficiency of agronomic protection from maize dwarf mosaic disease, susceptible maize inbred line was transformed by Agrobacterium tumefaciens harboring hpRNA expression vectors containing inverted-repeat sequences of different lengths targeting coat protein gene (CP) of maize dwarf mosaic virus (MDMV). After PCR screening and Southern blotting, the flanking sequences of the integration sites were amplified by thermal asymmetric interlaced PCR (TAIL-PCR) and used for analysis of T-DNA integration patterns. The T₂ plant lines were evaluated for their MDMV resistance in field inoculation trials under two environments. Of the nineteen T₂ plant lines positive in Southern blotting, six were evaluated as resistant to MDMV, and four of them had resistance non-significantly different from the highly resistant control "H9-21", while the resistance of the other eleven was proved to be significantly improved when compared to their non-transformed parent line. These improvements in MDMV resistance were verified by the relative amount of virus CP gene expression measured by quantitative real time PCR. Comparing the results of Southern blotting and TAIL-PCR analysis, different integration patterns of one or two copies of the inverted-repeat sequences were identified from non-repetitive and repetitive sequences of the maize genome. The MDMV resistance mediated by RNA interference is relative to the length of the inverted-repeat sequence, the copy number of T-DNA integration and the repeatability of integration sites. A longer hpRNA expression construct shows more efficiency than a shorter one. Copyright © 2011 Elsevier B.V. All rights reserved.
Full Text Available Transposable elements are capable of inducing heritable de novo genetic variation. The sequences capable of reactivation, and environmental factors that induce mobilization, remain poorly defined even in well-studied genomes such as maize. We treated maize tissue culture with the demethylating agent 5-aza-2-deoxcytidine and examined long-term tissue culture lines to discover silenced transposable elements that have the potential to induce heritable genetic variation. Through these screens we have identified a novel low copy number hAT transposon, Tissue Culture Up-Regulated (TCUP, which is transcribed at high levels in long-term maize Black Mexican Sweet (BMS tissue culture and up-regulated in response to treatment with 5-aza-2-deoxycytidine. Analysis of the TIGR Maize Gene Index revealed that this element is the most frequently represented EST from the BMS cell culture library and is not represented in other tissue libraries, which is the basis for its name. A full-length sequence was assembled in inbred B73 that contains the putative functional motifs required for autonomous movement of a hAT transposon. Transposon display detected movement of TCUP in two long-term tissue cultured cell lines of the genotype Hi-II AxB and BMS. This research implicates TCUP as a transposon that is capable of reactivation and which may also be particularly sensitive to the stress of the tissue culture environment. Our findings are consistent with the hypothesis that epigenetic alterations potentiate genomic responses to stress during clonal propagation of plants.
Mar 30, 2012 ... 26: 125-137. Morris, L.M. (1994). Assessing the benefits of international maize breeding research: An overview of the global maize impact study. CIMMYT maize research impacts survey. Pp 29-34. Norman, J.R. and Hooker, J.E. (2000). Sporulation of Phytophthora fragariae shows a greater stimulation by.
Full Text Available Maize plants apparently tolerant to maize streak virus were selected in farmer fields during a maize streak epidemie in the Burundi highlands in 1983-84. Progeny of these selections were tested under natural infection in the lowlands, with tolerant plants then either open or self-pollinated. Progeny of these tolerant plants were tested in the highlands using mass-reared Cicadulina vectors and a highland virus source, and ranged from very tolerant to susceptible. Inheritance of tolerance is consistent with its control by several genes and/or the presence of a number of modifying factors. A technique for mass rearing of vectors in a cool climate is presented.
Gershman, S N; Barnett, C A; Pettinger, A M; Weddle, C B; Hunt, J; Sakaluk, S K
Inbreeding is assumed to have negative effects on fitness, including the reduced ability to withstand immune challenges. We examined the immunological consequences of inbreeding in decorated crickets, Gryllodes sigillatus, by comparing lytic activity, phenoloxidase (PO) activity, and encapsulation ability of crickets from eight inbred lines with that of crickets from the outbred founder population. Surprisingly, crickets from inbred lines had a greater encapsulation ability compared with crickets from the outbred population. We suggest that because inbred crickets have reduced reproductive effort, they may, therefore, have the option of devoting more resources to this form of immunity than outbred individuals. We also found that both inbred and outbred females had higher immunity than males in PO activity and implant darkness. This result supports the hypothesis that females should devote more effort to somatic maintenance and immunity than males. PO activity and implant darkness were heritable in both males and females, but lytic activity was only heritable in females. Males and females differed in the heritability of, and genetic correlations among, immune traits, suggesting that differences in selective pressures on males and females may have resulted in a sexual conflict over optimal immune trait values.
Zhu, Yu-xi; Yang, Qun-fang; Huang, Yu-bi; Li, Qing
In the present study, we investigated the systematically induced production of defense-related compounds, including DIMBOA, total phenol, trypsin inhibitors (TI) and chymotrypsin inhibitor (CI), by Tetranychus cinnabarinus infestation in Zea mays. The first leaves of two corn in-bred line seedlings, the mite-tolerant line ' H1014168' and the mite-sensitive line 'H1014591', were sucked by T. cinnabarinus adult female for seven days, and then the contents of DIMBOA, total phenol, TI and CI were measured in the second leaf and in the roots, respectively. Results showed that as compared to the unsucked control, all contents of DIMBOA, total phenol, TI and CI induced by T. cinnabarinus sucking were significantly higher in the second leaf of both inbred lines as well as in the roots of the mite-tolerant 'H1014168'. However, in the roots of 'H1014591', these defense compounds had different trends, where there was a higher induction of TI and a lower level of total phenol than that of the healthy control, while had almost no difference in DIMBOA and CI. These findings suggested that the infestation of T. cinnabarinus could systematically induce accumulation of defense-related compounds, and this effect was stronger in the mite-tolerant inbred line than in the mite-sensitive inbred line.
MAKINO, J; KATO, K; MAES, FW
Behavior of the inbred mouse strains BALB, C3H, DBA and C57BL in an open field was directly observed for 10 min by a multi-event time sampling method. It was coded into nine behavioral items, the occurrence or absence of which in consecutive 5-s time bins was called a behavioral state. Fourteen
Two inbred lines of heading broccoli (Brassica oleracea L. var. italica), designated USVL048 and USVL131, were released by the Agricultural Research Service of the U.S. Department of Agriculture in 2012. Both of the released lines are doubled haploids originally derived from another culture. As do...
3Cátedra de Producción de Bovinos para carne, Facultad de Ciencias Veterinarias, CIC, Universidad Nacional de Rosario,. Argentina, Ov. Lagos y Ruta 33 (2170) Casilda, Argentina. [Renny M., Julio N. B., Bernardi S. F., Gardenal C. N. and Oyarzabal M. I. 2014 Estimation of genetic variability level in inbred CF1 mouse.
Wiltshire, T; Ervin, R B; Duan, H; Bogue, M A; Zamboni, W C; Cook, S; Chung, W; Zou, F; Tarantino, L M
Initial sensitivity to psychostimulants can predict subsequent use and abuse in humans. Acute locomotor activation in response to psychostimulants is commonly used as an animal model of initial drug sensitivity and has been shown to have a substantial genetic component. Identifying the specific genetic differences that lead to phenotypic differences in initial drug sensitivity can advance our understanding of the processes that lead to addiction. Phenotyping inbred mouse strain panels are frequently used as a first step for studying the genetic architecture of complex traits. We assessed locomotor activation following a single, acute 20 mg/kg dose of cocaine (COC) in males from 45 inbred mouse strains and observed significant phenotypic variation across strains indicating a substantial genetic component. We also measured levels of COC, the active metabolite, norcocaine and the major inactive metabolite, benzoylecgonine, in plasma and brain in the same set of inbred strains. Pharmacokinetic (PK) and behavioral data were significantly correlated, but at a level that indicates that PK alone does not account for the behavioral differences observed across strains. Phenotypic data from this reference population of inbred strains can be utilized in studies aimed at examining the role of psychostimulant-induced locomotor activation on drug reward and reinforcement and to test theories about addiction processes. Moreover, these data serve as a starting point for identifying genes that alter sensitivity to the locomotor stimulatory effects of COC. © 2015 John Wiley & Sons Ltd and International Behavioural and Neural Genetics Society.
Huang, X.; Caldas Paulo, M.J.; Boer, M.P.; Effgen, S.; Keizer, P.; Koornneef, M.; Eeuwijk, van F.A.
To exploit the diversity in Arabidopsis thaliana, eight founder accessions were crossed to produce six recombinant inbred line (RIL) subpopulations, together called an Arabidopsis multiparent RIL (AMPRIL) population. Founders were crossed pairwise to produce four F1 hybrids. These F1s were crossed
In order to study the effects of drought stress on yield and yield components of seven corn inbred lines, a field trial was conducted under non-stress and different drought stress conditions (stress at vegetative (6 to 7 leaves), pollination and grain filling stages) at the Agricultural College of Islamic Azad University, Shoushtar ...
The Agricultural Research Service, United States Department of Agriculture announces the release of a melon (Cucumis melo L.) breeding line with highly branched, fractal-type architectural growth habit and 81 derived recombinant inbred lines (RIL). The indeterminate, monoecious USDA 846-1 produces 2...
Abstract. Density functional theory calculations at the M06-2X level were done to study the reaction mech- anism and regioselectivity for the [2+2] cycloaddition of allyltrimethylsilane with alkynones using InBr3 as the catalyst. The solvent effect was described by the single-point calculations with SMD model in 1,2-.
Mišević, D; Gerić, I; Tadić, B
The evaluation of germplasm to identify its potential as a source of new favorable alleles is a time-consuming phase of maize hybrid breeding programs. The objective of this paper was to study the relationship between allozyme diversity and quantitative estimators of the relative number of new favorable alleles for grain yield, present in donor lines but not present in the elite hybrid. Twenty-two maize inbred lines representing heterotic groups from the United States (US) and Yugoslavia (YU) were used as donors to estimate the presence of new favorable alleles for grain yield improvement for the hybrid B73 x Mo17. In a second experiment, a 15-line diallel was grown, and 13 single crosses differing in allozyme relatedness measure (ARM) and heterotic grouping were considered as targets to be improved by the remaining 13 lines. Minimally biased estimates of new favorable alleles for grain yield (μG) and ARM values were made for all donor lines within each target hybrid. Donor lines were grouped in four allozyme-pedigree classes for each target hybrid to compare the effect of allozyme diversity with pedigree diversity. Pedigree dissimilarities had significant effects on μG estimates. Dissimilar pedigree classes had higher μG estimates than similar pedigree classes. Allozyme differences between donor inbred lines and target hybrids had inconsistent effects on μG estimates. Significant differences in μG estimates among allozyme classes were found for 31% of the target hybrids. Classes with similar allozymes had higher μG estimates more frequently than classes with disimilar allozymes. Correlation coefficients between μG estimates and ARM values were low and not significant for 12 of the 14 target hybrids.
Short wave infrared hyperspectral imaging (SWIR) (1000-2500 nm) was used to detect aflatoxin B1 (AFB1) in individual maize kernels. A total of 120 kernels of four varieties (or 30 kernels per variety) that had been artificially inoculated with a toxigenic strain of Aspergillus flavus and harvested f...
Lizárraga-Paulín, Eva-Guadalupe; Miranda-Castro, Susana-Patricia; Moreno-Martínez, Ernesto; Lara-Sagahón, Alma-Virginia; Torres-Pacheco, Irineo
Objective: To evaluate the effect of chitosan (CH) and hydrogen peroxide (H2O2) seed coatings and seedling sprinklings on two different maize varieties by measuring their phenology, the H2O2 presence, the catalase (CAT) activity, and the protein quantity. Methods: Seven groups of ten seeds for each maize variety were treated with CH (2% (20 g/L) and 0.2% (2 g/L)) or H2O2 (8 mmol/L) by coating, sprinkling, or both. Germination and seedling growth were measured. One month after germination, the presence of H2O2 in seedlings in the coated seed treatments was evaluated. Protein content and CAT activity were determined under all treatments. Results: H2O2 seed coating enhanced the germination rate and increased seedling and stem length in the quality protein maize (QPM) variety. Seedlings had a higher emergence velocity under this treatment in both varieties. CH and H2O2 sprinklings did not have an effect on seedling phenology. Exogenous application of H2O2 promoted an increase of endogenous H2O2. CH and H2O2 seedling sprinkling increased the protein content in both maize varieties, while there was no significant effect on the CAT activity of treated seeds and seedlings. Conclusions: CH and H2O2 enhance some phenological and biochemical features of maize depending on their method of application. PMID:23365007
Full Text Available Common bean (Phaseolus vulgaris L. is widely intercropped with maize (Zea mays L. in the North of Spain. Breeding beans for multiple cropping systems is important for the development of a productive and sustainable agriculture, and is mainly oriented to minimize intercrop competition and to stabilize complementarity with maize. Most agricultural research on intercropping to date has focused on the agronomic and overall yield effects of the different species, but characters related with socio-economic and food quality aspects are also important. The effect of intercropping beans with maize on food seed quality traits was studied for thirty-five bush bean varieties under different environments in Galicia (Northwestern Spain. Parameters determining Asturian (Northern Spain white bean commercial and culinary quality have also been evaluated in fifteen accessions. There are significant differences between varieties in the selected cropping systems (sole crop, intercrop with field maize and intercrop with sweet maize for dry and soaked seed weight, coat proportion, crude protein, crude fat and moisture. Different white bean accessions have been chosen according to their culinary quality. Under these environmental conditions it appears that intercropping systems with sweet maize give higher returns than sole cropping system. It is also suggested that the culinary and nutritional quality potential of some white bean accessions could be the base material in a breeding programme the objectives of which are to develop varieties giving seeds with high food quality.
Díaz-Gómez, Jorge L.; Castorena-Torres, Fabiola; Preciado-Ortiz, Ricardo E.; García-Lara, Silverio
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.
Deyana Gencheva Hristova
Full Text Available Taking into consideration that the growth hormone (GH gene in rabbits is a candidate for meat production, understanding the genetic diversity and variation in this locus is of particular relevance. The present study comprised 86 rabbits (Oryctolagus cuniculus divided into 3 groups: New Zealand White (NZW outbred rabbits; first-generation inbred rabbits (F1 and second-generation inbred rabbits (F2. They were analysed by polymerase chain reaction-based restriction fragment length polymorphism method. A 231 bp fragment of the polymorphic site of the GH gene was digested with Bsh1236 restriction enzyme. Single nucleotide polymorphisms for the studied GH locus corresponding to 3 genotypes were detected in the studied rabbit populations: CC, CT and TT. In the synthetic inbred F1 and F2 populations, the frequency of the heterozygous genotype CT was 0.696 and 0.609, respectively, while for the homozygous CC genotype the frequency was lower (0.043 and 0.000, and respective values for the homozygous TT genotype were 0.261 and 0.391. This presumed a preponderance of the T allele (0.609 and 0.696 over the C allele (0.391 and 0.304 in these groups. In outbred rabbits, the allele frequencies were 0.613 (allele C and 0.387 (allele Т; consequently, the frequency of the homozygous CC genotype was higher than that of the homozygous TT genotype (0.300 vs. 0.075. Observed heterozygosity for the GH gene was higher than expected, and the result was therefore a negative inbreeding coefficient (Fis=–0.317 for outbred NZW rabbits; –0.460 for inbred F1 and –0.438 for inbred F2, indicating a sufficient number of heterozygous forms in all studied groups of rabbits. The application of narrow inbreeding by breeding full sibs in the synthetic population did not cause a rapid increase in homozygosity.
Wallace, Andrew H
Homology Theory on Algebraic Varieties, Volume 6 deals with the principles of homology theory in algebraic geometry and includes the main theorems first formulated by Lefschetz, one of which is interpreted in terms of relative homology and another concerns the Poincaré formula. The actual details of the proofs of these theorems are introduced by geometrical descriptions, sometimes aided with diagrams. This book is comprised of eight chapters and begins with a discussion on linear sections of an algebraic variety, with emphasis on the fibring of a variety defined over the complex numbers. The n
P. D. Paulo
Full Text Available Abstract Plants can be attacked by a wide variety of herbivores. Thus, developing protective mechanisms for resistance against these agents is an advantage for survival and reproduction. Over the course of evolution, many resistance mechanisms against herbivory have been developed by the plants. Induced direct and indirect resistance mechanisms can manifest in plants after herbivore attack. The two-spotted spider mite Tetranychus urticae is not a pest of maize crops (Zea mays, despite being reported infesting plants that may have resistances against this herbivore. We tested the hypothesis that maize plants would be able to induce direct resistance against T. urticae after, evaluating the effect of T. urticae infestation in maize plants on the development and reproduction of conspecifics. We tested induced direct resistance performing infestation and measuring biological parameters upon a second infestation. Maize plants, 40 days after sowing, were divided into two groups: 30 not infested by T. urticae (clean plants clean and, 30 infested by the spider mite. Infestation of maize plants by T. urticae reduced the conspecific female adult survival. However, no change in the survival of immature or reproduction was observed. These results suggest the induction of induced direct resistances in maize by T. urticae. This is first report of direct resistance induction in Z. mays by the two-spotted spider mite T. urticae.
This paper presents an overview of the advances in the IRMA project, which develops insect resistant maize varieties for resource-poor farmers, using both conventional breeding and genetic engineering. The project started in 1999 and is active in product development, impact assessment, and communication, all within the ...
Etten, van J.
Crop genetic resources are an important aspect of agricultural production. Agricultural innovation through plant breeding is generally seen as an efficient means to support food security and economic development in poor areas. Modern varieties of maize, a major cereal and the subject of this study,
Torres, A.F.; Noordam-Boot, C.M.M.; Dolstra, O.; Vlaswinkel, L.; Visser, R.G.F.; Trindade, L.M.
The utilization of maize stover as a substrate for bioenergy production demands the development of dual-purpose hybrid varieties combining both, optimal grain yield and improved biomass processing amenability. In this study, our objectives were to assess how contrasting environments influence the
Dec 5, 2005 ... maize varieties for resource-poor farmers, using both conventional breeding and genetic engineering. The project started in 1999 .... classical backcrossing is used to move the gene from the. Transformed plant (CIMMYT ... Mendelian inheritance is observed to indicate that the event is stable. All of these ...
An experiment was carried out during the 2006 growing season, between June and November, to investigate the growth and yield responses of four varieties of maize (SUWAN-1-Y, TZSR-Y, DMESR-W and ACROSS-97 TZL) to time of fertilizer application (2,4 and 6 weeks after planting). The experiment was laid out in a 3 x ...
The effect of four varieties of soybean (TGX 1019-2 EB, TGX 1448 – 2E, TGX 1740 – 2F. TGX 1440 – IE) relayed into yam ministett/maize system on the yield of component crops and soil fertility of yam based system was investigated at National Root Crops Research Institute, substation Otobi, Benue State, Nigeria. Soybean ...
Full Text Available Abstract Background Polymorphisms were investigated within the ZmPox3 maize peroxidase gene, possibly involved in lignin biosynthesis because of its colocalization with a cluster of QTL related to lignin content and cell wall digestibility. The purpose of this study was to identify, on the basis of 37 maize lines chosen for their varying degrees of cell wall digestibility and representative of temperate regions germplasm, ZmPox3 haplotypes or individual polymorphisms possibly associated with digestibility. Results Numerous haplotypes with high diversity were identified. Frequency of nucleotide changes was high with on average one SNP every 57 bp. Nucleotide diversity was not equally distributed among site categories: the estimated π was on average eight times higher for silent sites than for non-synonymous sites. Numerous sites were in linkage disequilibrium that decayed with increasing physical distance. A zmPox3 mutant allele, carrying an insertion of a transposable element in the second exon, was found in lines derived from the early flint inbred line, F7. This element possesses many structural features of miniature inverted-repeat transposable elements (MITE. The mutant allele encodes a truncated protein lacking important functional sites. An ANOVA performed with a subset of 31 maize lines indicated that the transposable element was significantly associated with cell wall digestibility. This association was confirmed using an additional set of 25 flint lines related to F7. Moreover, RT-PCR experiments revealed a decreased amount of corresponding mRNA in plants with the MITE insertion. Conclusion These results showed that ZmPox3 could possibly be involved in monolignol polymerisation, and that a deficiency in ZmPox3 peroxidase activity seemingly has a negative effect on cell wall digestibility. Also, genetic diversity analyses of ZmPox3 indicated that this peroxidase could be a relevant target for grass digestibility improvement using
Mallana Gowdra Mallikarjuna
Full Text Available Deficiency of iron and zinc causes micronutrient malnutrition or hidden hunger, which severely affects ~25% of global population. Genetic biofortification of maize has emerged as cost effective and sustainable approach in addressing malnourishment of iron and zinc deficiency. Therefore, understanding the genetic variation and stability of kernel micronutrients and grain yield of the maize inbreds is a prerequisite in breeding micronutrient-rich high yielding hybrids to alleviate micronutrient malnutrition. We report here, the genetic variability and stability of the kernel micronutrients concentration and grain yield in a set of 50 maize inbred panel selected from the national and the international centres that were raised at six different maize growing regions of India. Phenotyping of kernels using inductively coupled plasma mass spectrometry (ICP-MS revealed considerable variability for kernel minerals concentration (iron: 18.88 to 47.65 mg kg(-1; zinc: 5.41 to 30.85 mg kg(-1; manganese: 3.30 to 17.73 mg kg(-1; copper: 0.53 to 5.48 mg kg(-1 and grain yield (826.6 to 5413 kg ha(-1. Significant positive correlation was observed between kernel iron and zinc within (r = 0.37 to r = 0.52, p < 0.05 and across locations (r = 0.44, p < 0.01. Variance components of the additive main effects and multiplicative interactions (AMMI model showed significant genotype and genotype × environment interaction for kernel minerals concentration and grain yield. Most of the variation was contributed by genotype main effect for kernel iron (39.6%, manganese (41.34% and copper (41.12%, and environment main effects for both kernel zinc (40.5% and grain yield (37.0%. Genotype main effect plus genotype-by-environment interaction (GGE biplot identified several mega environments for kernel minerals and grain yield. Comparison of stability parameters revealed AMMI stability value (ASV as the better representative of the AMMI stability parameters. Dynamic stability
Gerald N De La Fuente
Full Text Available Maize (Zea mays L. lipoxygenases (ZmLOXs are well recognized as important players in plant defense against pathogens, especially in cross kingdom lipid communication with pathogenic fungi. This study is among the first to investigate genetic diversity at important gene paralogs ZmLOX4 and ZmLOX5. Sequencing of these genes in 400 diverse maize lines showed little genetic diversity and low linkage disequilibrium in the two genes. Importantly, we identified one inbred line in which ZmLOX5 has a disrupted open reading frame, a line missing ZmLOX5, and five lines with a duplication of ZmLOX5. Tajima's D test suggests that both ZmLOX4 and ZmLOX5 have been under neutral selection. Further investigation of haplotype data revealed that within the ZmLOX family members only ZmLOX12, a monocot specific ZmLOX, showed strong linkage disequilibrium that extends further than expected in maize. Linkage disequilibrium patterns at these loci of interest are crucial for future candidate gene association mapping studies. ZmLOX4 and ZmLOX5 mutations and copy number variants are under further investigation for crop improvement.
Soengas, P; Butrón, A; Revilla, P; Ordás, A; Malvar, R A
Flint maize, Zea mays L., varieties provide some interesting agronomic characteristics and kernels that possess a better ability than other kernels for developing high-quality flour. The pink stem borer, Sesamia nonagrioides Lefebvre, is an important constraint for the maize crop in Mediterranean regions. The objective of this work was to identify a "flint x flint" heterotic pattern that would perform well under artificial infestation by S. nonagrioides. A 10-population diallel was evaluated under infestation by S. nonagrioides in 2 yr. Variety effects were the only significant effects involved in stem and ear resistance to S. nonagrioides attack. Variety effects and average heterosis effects were the only significant effects for grain yield under artificial infestation conditions. Considering variety effects and cross-performance, the heterotic pattern Basto/Enano levantixo x Longfellow (BA/EL x LO) would be recommended for obtaining flint maize hybrids tolerant to S. nonagrioides attack because BA/EL had the most favorable variety effects for stem resistance, LO exhibited the most positive variety effects for grain yield, and the cross BA/EL x LO yielded significantly more than the remaining crosses.
Abdel-Moneam, M A; Attia, A N; El-Emery, M I; Fayed, E A
In 2007, five maize inbred lines were crossed in all possible combinations without reciprocals by using a half diallel crosses mating design to obtain 10 single cross. Inbred parents and their F1 single crosses were evaluated through 2008 season to evaluate the role of general and specific combining ability and heterosis for some agronomic traits. Results indicated that mean squares of genotypes were highly significant for all studied traits, i.e., ear diameter, ear length, number of kernels/row, 100-kernel weight, ear yield per plant, grain yield per plant and shelling percentage. General Combining Ability (GCA) and Specific Combining Ability (SCA) mean squares were highly significant for all studied traits. The GCA/SCA ratio was less than unity for all studied traits; this means that these traits are predominantly controlled by non-additive gene action. Significant positive GCA effects were found for all studied traits. Based on GCA estimates, it could be concluded that the best combiners were Rg5 and Rg8 inbred lines for most of studied traits. This result indicated that these inbred lines could be considered as good combiners for improving these traits. Significant positive SCA effects were found for all studied traits. Based on SCA effects, it could be concluded that the best crosses for ear diameter and 100-kernels weigh was G507AxG516; for ear length was G516xRg8; for kernels number/row was G516xG278; for ear yield/plant, grain yield/plant and Shelling percentage was G278xRg5. These crosses could be selected and used in breeding programs for improving these traits. Results showed positive significant heterosis values for all studied traits. The best crosses over both their mid-parents and better-parents for ear diameter and 100-kernel weigh was G507AxG516; for ear length and kernels number/row was G516xG278; for ear yield/plant and grain yield/plant was G278xRg8 and for Shelling percentage was G278xRg5.
Cercospora zeina is a foliar pathogen responsible for maize grey leaf spot in southern Africa that negatively impacts maize production. Plants use a variety of chemical and structural mechanisms to defend themselves against invading pathogens such as C. zeina, including the production of secondary m...
Hansen, Johan Peder; Johnsen, Trygve; Ranestad, Kristian
We study subsets of Grassmann varieties G(l,m) over a field F, such that these subsets are unions of Schubert cycles, with respect to a fixed flag. We study unions of Schubert cycles of Grassmann varieties G(l,m) over a field F. We compute their linear span and, in positive characteristic......, their number of Fq -rational points. Moreover, we study a geometric duality of such unions, and give a combinatorial interpretation of this duality. We discuss the maximum number of Fq -rational points for Schubert unions of a given spanning dimension, and as an application to coding theory, we study...
Ylirisku, Salu; Arvola, Mattias
This chapter explores the philosopher and logician Georg Henrik von Wright’s metaethical treatise of the varieties of goodness in the context of design. von Wright investigated the use of notion of ‘good’ in language, and he identified six kinds of goodness: namely utilitarian goodness, instrumen......This chapter explores the philosopher and logician Georg Henrik von Wright’s metaethical treatise of the varieties of goodness in the context of design. von Wright investigated the use of notion of ‘good’ in language, and he identified six kinds of goodness: namely utilitarian goodness...
Gan, Defang; Ding, Fei; Zhuang, Dan; Jiang, Haiyang; Jiang, Tong; Zhu, Suwen; Cheng, Beijiu
Specific fragments of the sugarcane mosaic virus (SCMV) coat protein gene (cp) were amplified by reverse transcriptionpolymerase chain reaction and used to construct a marker free small interfering RNA complex expression vector against SCMV. In planta transformation was performed on maize (Zea mays) inbred line 8112 mediated by Agrobacterium tumefaciens. PCR and Southern blot analyses demonstrated successful integration of the cp segment into the 8112 genome. The in planta transformation frequency was 0.1%, and the cotransformed frequency with the cp and bar genes was 0.034%. Real-time quantitative PCR of samples from different transgenic plant organs showed that the expression of the cp gene fragment in transgenic plants was variable and that the highest expression level occurred in the tassels and leaves and the lowest expression occurred in the roots. Real-time quantitative PCR was also used to measure how gene expression in transgenic T2 generation plants inoculated with SCMV changes over time. The results showed that the hairpin RNA structure transcribed from the cp gene interfered with SCMV infection and transgenic maize lines were not equally effective in preventing SCMV infection. Our findings provide a valuable tool for controlling plant viruses using RNA interference and the posttranslational gene silencing approach.
Sheng, Yanmin; Wang, Yingdian; Capell, Teresa; Shi, Lianxuan; Ni, Xiuzhen; Sandmann, Gerhard; Christou, Paul; Zhu, Changfu
The assignment of functions to genes in the carotenoid biosynthesis pathway is necessary to understand how the pathway is regulated and to obtain the basic information required for metabolic engineering. Few carotenoid ε-hydroxylases have been functionally characterized in plants although this would provide insight into the hydroxylation steps in the pathway. We therefore isolated mRNA from the endosperm of maize (Zea mays L., inbred line B73) and cloned a full-length cDNA encoding CYP97C19, a putative heme-containing carotenoid ε hydroxylase and member of the cytochrome P450 family. The corresponding CYP97C19 genomic locus on chromosome 1 was found to comprise a single-copy gene with nine introns. We expressed CYP97C19 cDNA under the control of the constitutive CaMV 35S promoter in the Arabidopsis thaliana lut1 knockout mutant, which lacks a functional CYP97C1 (LUT1) gene. The analysis of carotenoid levels and composition showed that lutein accumulated to high levels in the rosette leaves of the transgenic lines but not in the untransformed lut1 mutants. These results allowed the unambiguous functional annotation of maize CYP97C19 as an enzyme with strong zeinoxanthin ε-ring hydroxylation activity. PMID:26030746
Zhang, Cai-Bo; Wu, Zhang-Dong; Xu, Dong-Ping; Liu, He-Yang; Rong, Ting-Zhao; Cao, Mo-Ju
Three maize (Zea mays L.) inbred lines 08-641, RP125, and 18-599 were carried into cosmic space by recoverable satellite "Shijian 8". Some mutant lines were selected from SP4 and combinations were made according to the NC II genetic design. The materials were planted in Sichuan and Yunnan separately to analyze combining ability based on the incomplete diallel cross design. The results showed that space flight affected the combining ability of mutant lines, and the GCA value of mutant lines were different in two kinds of environmental condition. The GCA of ear length, row per ear, kernel per row, and yield per plant for the mutant line C03 showed substantial increase compared with the control 08-641; the GCA of row per ear, kernel per row, and other yield component traits for the mutant lines C01 and C04 were significantly higher than those of the control. The SCA of yield and yield components for the combinations derived from the mutant lines C06, R18, and S22 were higher than others. These results laid a material foundation for maize breeding and provided some important references for improving and utilizing the mutant lines.
Full Text Available Teosinte ( subsp. H. H. Iltis & Doebley has greater genetic diversity than maize inbreds and landraces ( subsp. . There are, however, limited genetic resources to efficiently evaluate and tap this diversity. To broaden resources for genetic diversity studies in maize, we developed and evaluated 928 near-isogenic introgression lines (NILs from 10 teosinte accessions in the B73 background. Joint linkage analysis of the 10 introgression populations identified several large-effect quantitative trait loci (QTL for days to anthesis (DTA, kernel row number (KRN, and 50-kernel weight (Wt50k. Our results confirm prior reports of kernel domestication loci and identify previously uncharacterized QTL with a range of allelic effects enabling future research into the genetic basis of these traits. Additionally, we used a targeted set of NILs to validate the effects of a KRN QTL located on chromosome 2. These introgression populations offer novel tools for QTL discovery and validation as well as a platform for initiating fine mapping.
de Jong, Guilherme; Pamplona, Andrezza Kellen Alves; Von Pinho, Renzo Garcia; Balestre, Marcio
The identification of causal regions associated with resistance to Fusarium verticillioides can be useful to understand resistance mechanisms and further be used in breeding programs. In this study, a genome-wide association study (GWAS) was conducted to identify candidate markers associated with resistance to the ear rot caused by the fungus F. verticillioides. A total of 242 maize inbred lines were genotyped with 23,153 DArT-seq markers. A total of 12 DArTs were associated with ear rot resistance. Some DArTs were localized close to genes with functions directly related to ear rot resistance, such as a gene responsible for the innate immune response that belongs to the class of NBS-LRR receptors. Some markers were also found to be closely associated with genes that synthesize transcription factors (nactf11 and nactf61), genes responsible for the oxidation-reduction process and peroxidase activity. These results are encouraging since some candidate markers can present functional relationship with ear rot resistance in maize. Copyright © 2017 Elsevier Inc. All rights reserved.
Full Text Available The assignment of functions to genes in the carotenoid biosynthesis pathway is necessary to understand how the pathway is regulated and to obtain the basic information required for metabolic engineering. Few carotenoid ε-hydroxylases have been functionally characterized in plants although this would provide insight into the hydroxylation steps in the pathway. We therefore isolated mRNA from the endosperm of maize (Zea mays L., inbred line B73 and cloned a full-length cDNA encoding CYP97C19, a putative heme-containing carotenoid ε hydroxylase and member of the cytochrome P450 family. The corresponding CYP97C19 genomic locus on chromosome 1 was found to comprise a single-copy gene with nine introns. We expressed CYP97C19 cDNA under the control of the constitutive CaMV 35S promoter in the Arabidopsis thaliana lut1 knockout mutant, which lacks a functional CYP97C1 (LUT1 gene. The analysis of carotenoid levels and composition showed that lutein accumulated to high levels in the rosette leaves of the transgenic lines but not in the untransformed lut1 mutants. These results allowed the unambiguous functional annotation of maize CYP97C19 as an enzyme with strong zeinoxanthin ε-ring hydroxylation activity.
Sara Regina Silvestrin Rovaris
Full Text Available In Brazil, there is a shortage of white maize cultivars and genetic studies for special maize breeding programs. This study aimed to identify populations and promising hybrid white maize for main agronomic traits and grits processing and to estimate the genetic parameters of parents and heterosis. In the 2012/13 growing season, fifteen hybrids were obtained by complete diallel crosses, and six parental and commercial check varieties were evaluated for: female flowering (FF, ear height (EH, grain yield (GY, ear length (EL, volumetric mass (VM and grits processing (GP in two locations in São Paulo State, Campinas and Mococa, using a randomized block design. Analyses of variance were carried out, and diallel crosses were performed using the Gardner and Eberhart model. The populations P3 and P6 stood out because of the estimated effects of the parents and of heterosis; the studied characters are promising for obtaining new lines and forming composites. For GP, the treatments showed no differences, implying the need to introduce new sources of germplasm.
Moradi Shahmansouri, Nastaran
Nanomaterials are widely used in many different products, such as electronics, cosmetics, industrial goods, biomedical uses, and other material applications. The heavy emission of nanomaterials into the environment has motived increasing concern regarding the effects on ecosystems, food chains, and, human health. Plants can tolerate a certain amount of natural nanomaterials, but large amounts of ENMs released from a variety of industries could be toxic to plants and possibly threaten the ecosystem. Employing phytoremediation as a contamination treatment method may show promise. However a pre-requisite to successful treatment is a better understanding of the behavior and effects of nanomaterials within plant systems. This study is designed to investigate the uptake, translocation, bioavailability, and toxicity of gold nanorods in maize plants. Maize is an important food and feed crop that can be used to understand the potential hazardous effects of nanoparticle uptake and distribution in the food chain. The findings could be an important contribution to the fields of phytoremediation, agri-nanotechnology, and nanoparticle toxicity on plants. In the first experiment, hydroponically grown maize seedlings were exposed to similar doses of commercial non-coated gold nanorods in three sizes, 10x34 nm, 20x75 nm, and 40x96 nm. The three nanorod species were suspended in solutions at concentrations of 350 mg/l, 5.8 mg/l, and 14 mg/l, respectively. Maize plants were exposed to all three solutions resulting in considerably lower transpiration and wet biomass than control plants. Likewise, dry biomass was reduced, but the effect is less pronounced than that of transpiration and wet biomass. The reduced transpiration and water content, which eventually proved fatal to exposed plants, were most likely a result of toxic effect of gold nanorod, which appeared to physically hinder the root system. TEM images proved that maize plants can uptake gold particles and accumulate them in
Ahmed Medhat M. Al-Naggar
Full Text Available Increasing plant density and improving N fertilizer rate along with the use of high density-tolerant genotypes would lead to maximizing maize (Zea mays L. grain productivity per unit land area. The objective of this investigation was to match the functions of optimum plant density and adequate nitrogen fertilizer application to produce the highest possible yields per unit area with the greatest maize genotype efficiency. Six maize inbred lines differing in tolerance to low N and high density (D [three tolerant (T; L-17, L-18, L-53, and three sensitive (S; L-29, L-54, L-55] were chosen for diallel crosses. Parents and crosses were evaluated in the 2012 and 2013 seasons under three plant densities: low (47,600, medium (71,400, and high (95,200 plants ha− 1 and three N fertilization rates: low (no N addition, medium (285 kg N ha− 1 and high (570 kg N ha− 1. The T × T crosses were superior to the S × S and T × S crosses under the low N–high D environment in most studied traits across seasons. The relationships between the nine environments and grain yield per hectare (GYPH showed near-linear regression functions for inbreds L54, L29, and L55 and hybrids L18 × L53 and L18 × L55 with the highest GYPH at a density of 47,600 plants ha− 1 and N rate of 570 kg N ha− 1 and a curvilinear relationship for inbreds L17, L18, and L53 and the rest of the hybrids with the highest GYPH at a density of 95,200 plants ha− 1 combined with an N rate of 570 kg N ha− 1. Cross L17 × L54 gave the highest grain yield in this study under both high N–high-D (19.9 t ha− 1 and medium N–high-D environments (17.6 t ha− 1.
Krause, W; Viana, A P; Cavalcante, N R; Ambrósio, M; Santos, E A; Vieira, H D
Digital image analysis of seeds has been used for the identification of cultivars, determination of seed color and mechanical damage, and classification of different seed sizes. The aim of the present study was to evaluate the efficiency of digital image analysis of seeds for the quantification of genetic diversity among genotypes of inbred guava (Psidium guajava L.) families. The SAS Mini equipment, which consists of a capture module and a software program for analysis, was employed for the capture and analysis of the seed images. Different genetic diversity quantification strategies were tested using the Ward-Modified Location Model method. The set of variables related to geometry of the seeds was the largest contributor to divergence among the guava genotypes. The use of seed descriptors obtained by digital image analysis via the SAS system was efficient at quantifying the genetic diversity among genotypes of inbred guava families associated with the use of the Ward-Modified Location Model method.
Jiang, Lu; Ingvardsen, Christina Rønn; Lübberstedt, Thomas
Sugarcane mosaic virus (SCMV) is the causal pathogen for a severe mosaic virus disease of maize worldwide. In our previous research, the maize resistance gene analog (RGA) Pic19 and its three cognate BAC contigs were mapped to the same region as the SCMV resistance gene Scmv1. Here we report the ...... of the Pic19R family indicated that the Pic19R-1 paralog is identical to the known Rxo1 gene conferring resistance to rice bacterial streak disease and none of the other Pic19R paralogs seems to be involved in resistance to SCMV......Sugarcane mosaic virus (SCMV) is the causal pathogen for a severe mosaic virus disease of maize worldwide. In our previous research, the maize resistance gene analog (RGA) Pic19 and its three cognate BAC contigs were mapped to the same region as the SCMV resistance gene Scmv1. Here we report...... the isolation and characterization of the Pic19R gene family members from the inbred line FAP1360A, which shows complete resistance to SCMV. Two primer pairs were designed based on the conserved regions among the known Pic19 paralogs and used for rapid amplification of cDNA ends of FAP1360A. Six full-length c...