Alley cropping of Cassia siamea and maize was studied in semi-arid Kenya for soil fertility improvement. Katumani composite maize was planted except in the short rains of 1988 (SR88) when a hybrid variety was sown. Therefore the grain yield per row increased differently in the alley cropped maize (C...

Grain yields for dryland maize (Zea mays L.) production in the semi-arid Great Plains of the United States can be unpredictable because of the erratic nature of growing season precipitation. Because of the high input costs for maize production, farmers need to have a tool that will help them assess the risk associated with dryland maize production. The objectives of this work were to determine the critical period for precipitation during the maize growing season and to develop a relationship between critical period precipitation and maize yield to use as a tool to quantify expected yield variability associated with dryland maize production in this region. Maize yield data were collected at Akron, CO from two dryland cropping systems experiments (1984-2009) in which maize was grown in a 3-y...

Ear rots of maize, caused by Fusarium spp., are of major concern because they lead to losses in grain yield and contamination with mycotoxins which harm animals and humans. In the absence of other strategies, breeding maize for genetic resistance is currently the most promising avenue to control the...

As a follow-up to our earlier investigation on the effect of gamma radiation on the germination and growth of certain Nigerian agricultural crops, the present study sought to determine the effect of gamma radiation on the grain yield of Zea mays (maize) and Arachis hypogaea (groundnut). The seeds were planted after irradiation without the application of fertiliser. The results show that for maize, grain yield for irradiated samples is increased to levels above the unirradiated yield at doses up to about 250 Gy with the optimum yield occurring at 150 Gy. The corresponding increase for groundnut is observed at doses up to about 930 Gy with optimum yield at a dose of 300 Gy. Inhibition in yield was observed to set in at a dose greater than 250 Gy for maize and 930 Gy for groundnut. The actual relationship between mean yield of these crops and gamma radiation dose was obtained using sixth-degree polynomial equations. (note)

Fusarium head blight (FHB), or scab, is one of the most devastating fungal diseases affecting small-grain cereals and maize, causing severe yield losses and contamination of grain with mycotoxins such as deoxynivalenol (DON) worldwide. Fusarium graminearum (teleomorph Gibberella zeae) and Fusarium c...

As a part of a habitat management strategy aimed at controlling Chilo partellus Swinhoe, Napier millet (Pennisetum purpureum × P. glaucum) was evaluated as a trap crop surrounding maize during 2008 and 2009 at Ludhiana, North India. Napier millet borders surrounding maize were compared to chemically protected maize and control maize plots for their effects on C. partellus oviposition, plant infestation and grain yield. Further experiments were carried out to determine whether adult experience could affect subsequent oviposition on test plants. Maize plots surrounded by Napier millet had fewer plants with borer eggs than control maize plots, although the results were significant only for the 2009 season. Percentage plant infestation and percentage dead hearts were less in Nap...

Intercropping, which grows at least two crop species on the same pieces of land at the same time, can increase grain yields greatly. Legume-grass intercrops are known to overyield because of legume nitrogen fixation. However, many agricultural soils are deficient in phosphorus. Here we show that a new mechanism of overyielding, in which phosphorus mobilized by one crop species increases the growth of a second crop species grown in alternate rows, led to large yield increases on phosphorus-deficient soils. In 4 years of field experiments, maize (Zea mays L.) overyielded by 43% and faba bean (Vicia faba L.) overyielded by 26% when intercropped on a low-phosphorus but high-nitrogen soil. We found that overyielding of maize was attributable to below-ground interactions between faba bean and maize in another field experiment. Intercropping with faba bean improved maize grain yield significantly and above-ground biomass marginally significantly, compared with maize grown with wheat, at lower rates of P fertilizer application (112.5 kg of P(2)O(5) per hectare). By using permeable and impermeable root barriers, we found that maize overyielding resulted from its uptake of phosphorus mobilized by the acidification of the rhizosphere via faba bean root release of organic acids and protons. Faba bean overyielded because its growth season and rooting depth differed from maize. The large increase in yields from intercropping on low-phosphorus soils is likely to be especially important on heavily weathered soils. PMID:17592130

Stenocarpella ear rot of maize caused by Stenocarpella maydis (Berk.) Sutton is one of the most important ear rot diseases in South Africa. The objective of this study was to identify suitable maize inbred lines and top cross hybrids with Stenocarpella ear rot resistance and high grain yield. The study was conducted using 54 inbred lines and 54 top crosses with selected standard checks under natural and artificial disease inoculations. A split-plot design was used with three replications. There were considerable variations among tested inbred lines and top crosses for Stenocarpella ear rot resistance and grain yield. Two promising inbred lines GCI-35 and GCI-50 were selected possessing resistance to Stenocarpella ear rot and increased grain yield. Inbred line GCI-35 had a grain yield of 6....

Maize ear rots reduce grain yield and quality with implication on food security and health. Some of the pathogenic fungi produce mycotoxins in maize grain posing a health risk to humans and livestock. Unfortunately, the levels of ear rot and mycotoxin infection in grain produced by subsistence farmers in sub-Saharan countries are not known. A survey was thus conducted to determine the prevalence of the ear rot problem and levels of mycotoxins in maize grain. A total of 114 farmsteads were randomly sampled from 11 districts in Lusaka and southern provinces in Zambia during 2006. Ten randomly picked cobs were examined per farmstead and the ear rot disease incidence and severity were estimated on site. This was followed by the standard seed health testing procedures for fungal isolation in the laboratory. Results indicated that the dominant ear rots were caused by Fusarium and Stenocarpella. Incidence of Fusarium verticillioides ranged from 2 to 21%, whereas that of Stenocarpella maydis reached 37% on ear rot diseased maize grain. In addition, 2-7% F. verticillioides, and 3-18% Aspergillus flavus, respectively, were recovered from seemingly healthy maize grain. The mean rank of fungal species, from highest to lowest, was F. verticillioides, S. maydis, A. flavus, Fusarium graminearum, Aspergillus niger, Penicillium spp., Botrydiplodia spp., and Cladosporium spp. The direct competitive ELISA-test indicated higher levels of fumonisins than aflatoxins in pre-harvest maize grain samples. The concentration of fumonisins from six districts, and aflatoxin from two districts, was 10-fold higher than 2 ppm and far higher than 2 ppb maximum daily intake recommended by the FAO/WHO. The study therefore suggested that subsistence farmers and consumers in this part of Zambia, and maybe also in similar environments in sub-Saharan Africa, might be exposed to dangerous levels of mycotoxins due to the high levels of ear rot infections in maize grain. PMID:20626099

This paper presents the findings of the effect of some selected deficit irrigation scheduling practices on irrigated maize crop in a sub-catchment in south western part of Tanzania. Field experiments, in which maize (TMV1-ST) variety was planted under total irrigation, were conducted during the dry seasons of 2004 and 2005. Surface irrigation method was used and the crop was planted in basins. The seasonal water applied ranged from 400 to 750 mm. Soil moisture content from both cropped and bare soils, leaf area index, dry matter, and grain yields were measured. The dry matter yield ranged between 6,966 and 12,672 kg/ha, and grain yields obtained were between 1,625 and 4,349 kg/ha. The results showed that deficit irrigation at any crop growth stage of the maize crop led to decrease in dry m...

The aim of this study was to explore the effects of water stress on the growth, biomass partitioning, and water-use efficiency (WUE) of summer maize (Zea mays L.) throughout the growth cycle. Maize field trials were conducted under a completely randomized design with three field water capacity (FC) regimes. Water was delivered to plants as follows: 75% FC was considered low water stress and the control, 55% FC medium stress, and 35% FC high stress. The controlled irrigation was initiated from the third leaf stage until maturity. The results of 2?years of field trials indicated that maize development and grain yield responses to water stress depended on the severity of stress, including intensity and duration, but also on maize developmental stage. Medium water stress (55%) affected leaf ar...

Fusarium ear rot, primarily caused by Fusarium verticillioides, causes losses in grain yield and quality and can result in contamination of grain by mycotoxins, primarily fumonisin B1. Disease severity and fumonisin B1 contamination vary considerably among maize-growing regions and from year to year. A 2-year field study was conducted in six locations in the USA, to evaluate the roles of planting date, maize hybrid, rainfall, temperature and insect pests in the variation in fusarium ear rot symptoms and fumonisin B1 contamination. Grain samples were inspected to determine percentage of kernels with fusarium ear rot symptoms, categorized as -moulded- or -starburst-; grain was also analysed by ELISA for fumonisin B1. Hybrid and planting date frequently had significant effects (P---005) on fu...

Studies on the sustainability of crop production systems should consider both the carbon (C) footprint and the crop yield. Knowledge is urgently needed to estimate the C cost of maize (Zea mays L.) production in a continuous monoculture or in rotation with a leguminous crop, the popular rotation system in North America. In this study, we used a 19-year field experiment with maize under different levels of synthetic N treatments in a continuous culture or rotation with forage legume (Alfalfa or red clover; Medicago sativa L./Trifolium pratense L.) or soybean (Glycine max L. Merr) to assess the sustainability of maize production systems by estimating total greenhouse gas (GHG) emissions (kg?CO2 eq?ha?1) and the equivalent C cost of yield or C footprint (kg?CO2 ?eq?kg?1?grain). High N applica...

Studies on the sustainability of crop production systems should consider both the carbon (C) footprint and the crop yield. Knowledge is urgently needed to estimate the C cost of maize (Zea mays L.) production in a continuous monoculture or in rotation with a leguminous crop, the popular rotation system in North America. In this study, we used a 19-year field experiment with maize under different levels of synthetic N treatments in a continuous culture or rotation with forage legume (Alfalfa or red clover; Medicago sativa L./Trifolium pratense L.) or soybean (Glycine max L. Merr) to assess the sustainability of maize production systems by estimating total greenhouse gas (GHG) emissions (kg CO2 eq ha?1) and the equivalent C cost of yield or C footprint (kg CO2  eq kg?1 grain). High N applica...

Optimal nitrogen (N) supply is critical for achieving high grain yield of maize. It is well established that N deficiency significantly reduces grain yield and N oversupply reduces N use efficiency without significant yield increase. However, the underlying proteomic mechanism remains poorly understood. The present field study showed that N deficiency significantly reduced ear size and dry matter accumulation in the cob and grain, directly resulting in a significant decrease in grain yield. The N content, biomass accumulation, and proteomic variations were further analysed in young ears at the silking stage under different N regimes. N deficiency significantly reduced N content and biomass accumulation in young ears of maize plants. Proteomic analysis identified 47 proteins with significant differential accumulation in young ears under different N treatments. Eighteen proteins also responded to other abiotic and biotic stresses, suggesting that N nutritional imbalance triggered a general stress response. Importantly, 24 proteins are involved in regulation of hormonal metabolism and functions, ear development, and C/N metabolism in young ears, indicating profound impacts of N nutrition on ear growth and grain yield at the proteomic level. PMID:22936831

To differentiate the impacts of grains (reproductive tissues) and cob plus husks (vegetative tissues) on biomass accumulation, nitrogen (N), phosphorus (P), and potassium (K) uptake and their distribution within maize plants, six Chinese maize varieties with different yield potentials released in last 60 years were employed in a two-year field experiment. Ears were either covered or removed at silking, the dry weight (DW) and NPK contents at silking and maturity in major sink organs of plants were closely observed. In comparison with control plants, covering ears reduced, and removing ears further decreased total DW and NP gains of whole plants, regardless of the larger root size and reduced shoot:root DW ratio. Since the total DW and NP gains of the new maize varieties after silking were ...

Optimal sowing date is essential to attain high maize (Zea mays L.) productivity despite environmental variation in low-input agriculture in Zambia. Local farmers generally plant maize as early as possible after the onset of the rainy season. However, there is no scientific evidence that this timing is optimal for attaining high productivity using local practices. To address this probem, we grew maize at three sowing dates in six fields of Zambia’s Southern Province in the 2008/09 and 2009/10 growing seasons. Grain yield was reduced by delayed sowing, by an average of 19% for all years and locations combined. The reduction resulted from decreased biomass production and harvest index. These results support the early sowing practice applied by local farmers.   

Advances in precision agriculture technology have led to the development of ground-based active remote sensors that can determine normalized difference vegetation index (NDVI). Studies have shown that NDVI is highly related to leaf nitrogen (N) content in maize (Zea mays L.). Remotely sensed NDVI can provide valuable information regarding in-field N variability and significant relationships between sensor NDVI and maize grain yield have been reported. While numerous studies have been conducted using active sensors, none have focused on the comparative effectiveness of these sensors in maize under semi-arid irrigated field conditions. Therefore, the objectives of this study were (1) to determine the performance of two active remote sensors by determining each sensor?s NDVI relationship with...

To increase maize (Zea mays L.) yields in drought-prone environments and offset predicted maize yield losses under future climates, the development of improved breeding pipelines using a multi-disciplinary approach is essential. Elucidating key growth processes will provide opportunities to improve drought breeding progress through the identification of key phenotypic traits, ideotypes, and donors. In this study, we tested a large set of tropical and subtropical maize inbreds and single cross hybrids under reproductive stage drought stress and well-watered conditions. Patterns of biomass production, senescence, and plant water status were measured throughout the crop cycle. Under drought stress, early biomass production prior to anthesis was important for inbred yield, while delayed senescence was important for hybrid yield. Under well-watered conditions, the ability to maintain a high biomass throughout the growing cycle was crucial for inbred yield, while a stay-green pattern was important for hybrid yield. While new quantitative phenotyping tools such as spectral reflectance (Normalized Difference Vegetation Index, NDVI) allowed for the characterisation of growth and senescence patterns as well as yield, qualitative measurements of canopy senescence were also found to be associated with grain yield. PMID:22925524

Abstract in portuguese Avaliaram-se 17 genótipos híbridos de milho na Turquia, em quatro diferentes locais e épocas de cultivo e sob irrigação, durante 2005 e 2006. A análise de variância revelou que os quadrados médios para ambientes (E), genótipos (G) e interação G x E foram altamente significantes e corresponderam a 74, 7 e 19 % da soma de quadrados da combinação tratamentos, respectivamente. Os dados foram submetidos à análise de GGE biplot para se determinar os efeitos da in (more) teração G x E na produção de grãos, O híbrido G16 revelou-se altamente produtivo nos locais de teste. Yenisehir se mostrou o mais representativo dos locais, para tomada de decisão sobre a recomendação de híbridos experimentais. Por fim, a tomada da produção de grãos por planta ao invés da produção por parcela nos programas de melhoramento de híbridos de milho apresentou algumas vantagens e deve ser preferida pelas companies privadas. Abstract in english Seventeen hybrid maize genotypes were evaluated at four different locations in 2005 and 2006 cropping seasons under irrigated conditions in Turkey. The analysis of variance showed that mean squares of environments (E), genotypes (G) and GE interactions (GEI) were highly significant and accounted for 74, 7 and 19 % of treatment combination sum squares, respectively. To determine the effects of GEI on grain yield, the data were subjected to the GGE biplot analysis. Maize hy (more) brid G16 can be proposed as reliably growing in test locations for high grain yield. Also, only the Yenisehir location could be best representative of overall, locations for deciding about which experimental hybrids can be recommended for grain yield in this study. Consequently, using of grain yield per plant instead of grain yield per plot in hybrid maize breeding programs could be preferred by private companies due to some advantages.

Abstract in portuguese O objetivo deste trabalho foi avaliar a ocorrência de plantas daninhas, o estado nutricional e a produtividade do milho e de Brachiaria brizantha consorciados em diferentes arranjos de semeadura da braquiária, tratados com a mistura dos herbicidas nicosulfuron + atrazine e atrazine. Nas parcelas, os tratamentos foram constituídos das semeaduras de milho e B. brizantha em monocultivo, mais quatro formas de estabelecimento da braquiária, representadas pela semeadura de (more) uma e duas linhas de braquiária na entrelinha do milho; pela semeadura na mesma linha do milho; e pela semeadura da forrageira a lanço na entrelinha do milho. Nas subparcelas, os dois tratamentos secundários constaram do uso da mistura dos herbicidas nicosulfuron + atrazine (8 + 1.500 g ha-1) e atrazine (1.500 g ha-1), aplicados aos 30 dias após a emergência (DAE) do milho. Foram avaliados a biomassa seca da comunidade infestante aos 30 dias após a aplicação (DAA) dos herbicidas, os níveis de macronutrientes, o rendimento de grãos e o peso de mil sementes no milho, bem como a produção de biomassa seca total e o acúmulo de macronutrientes pela forrageira. As espécies Brachiaria plantaginea, Brachiaria decumbens e Sorghum arundinaceum foram controladas pela mistura de nicosulfuron + atrazine; entretanto, as demais espécies, constituídas por Digitaria horizontalis, Cyperus rotundus e Artemisia verlotorum, não foram controladas pela mistura de herbicidas. Menores níveis de clorofila total e de N nas folhas de milho foram observados quando cultivadas duas linhas de braquiária na entrelinha do milho. Quando se utilizou a mistura de nicosulfuron + atrazine, foram observados no milho maiores teores de clorofila total, N, P e K e de rendimento de grãos e peso de mil sementes, comparados aos tratamentos que não receberam esses produtos. Ao utilizar duas linhas da semeadura de B. brizantha em associação com o milho, foi observada maior ocupação do solo pelas espécies cultivadas, maior produção de forragem e, conseqüentemente, maior quantidade de nutrientes incorporada a essa biomassa, sem afetar significativamente a produção da cultura. Abstract in english The aim of this study was to evaluate the occurrence of weeds, nutritional state and yield of maize - B. brizantha intercrop under different layouts of Brachiaria pasture sowing treated with the herbicide mixture nicosulfuron + atrazine and atrazine. In the plots, the treatments consisted in maize and B. brizantha sowing in single crops, besides four forms of establishing B. brizantha by sowing one and two rows of B. brizantha in-between the maize rows; sowing along the s (more) ame row as maize; and sowing the forage scattered in-between the maize rows. In the subplots, the two secondary treatments consisted in using the herbicide mixture nicosulfuron + atrazine (8 + 1,500 g ha-1) and atrazine (1,500 g ha-1) applied 30 days after emergence (DAE). Dry biomass of the macronutrient levels, grain yield and the weight of a thousand maize kernels, as well as the total dry matter yield and macronutrients accumulated by the pasture were evaluated. The weed species Brachiaria plantaginea, Brachiaria decumbens, and Sorghum arundinaceum were controlled by the mixture nicosulfuron + atrazine; the species Digitaria horizontalis, Cyperus rotundus, and Artemisia verlotorum were not controlled by the herbicide mixture. Lower levels of total chlorophyll and N leaf contents in maize were observed when two rows of B. brizantha were cultivated in-between the maize rows. When the herbicide mixture nicosulfuron + atrazine was used, highest levels of total chlorophyll, N, P, and K, grain yield, and weight of a thousand kernels were observed in maize compared to the treatments without product application. When two rows of B. brizantha were cultivated in-between the maize rows, a greater occupation of soil by the cultivated species, greater yield forage and greater amount of nutrients incorporated of this biomass were observed, without significantly affecting maize yield grain.

Mussidia nigrivenella Ragonot is a pest of maize cobs in West Africa. It significantly reduces maize yields and grain quality, with quantitative losses of 2-25%at harvest, and up to 10-15% indirect losses due to an increase in storage pest infestation levels. Infestation by M. nigrivenella also significantly increased the susceptibility of maize to Aspergillus flavus infection and subsequent aflatoxin contamination. Surveys conducted in different agro-ecological zones of Benin on cultivated and wild host plants during 1994-1997 revealed one egg parasitoid, three larval parasitoids and one pupal parasitoid attacking M. nigrivenella. Egg parasitism was scarce on all host plants sampled and in all four agro-ecological zones. Parasitism by larval and pupal parasitoids was usually less than 10%, and varied with host plant species. Both larval and pupal parasitoids were rare or absent in cultivated maize fields. The solitary chalcidid pupal parasitoid, Antrocephalus crassipes Masi, was the predominant species, contributing approximately 53% of the observed mortality. Logistic regression analysis indicated that this parasitoid was more prevalent on fruits of Gardenia spp. (Rubiaceae) than on the other host plant species including maize used by M. nigrivenella, and was most abundant between February and September. The differences in parasitoid diversity and parasitism between Benin and other regions suggest that there are opportunities for biological control through introduction of exotic parasitoids or using the 'new association' approach, which uses natural enemies of closely related host species that occupy similar ecological niches to the target pest. PMID:12191443

Over the past 3 decades, the study of various mechanisms involved in maize grain yield (GY) formation and its relationship with nitrogen (N) uptake dynamics has been increasingly acknowledged in the scientific literature. However, few studies have combined investigations of GY response to N fertilizer with detailed physiologically based analyses of plant N dynamics such as N uptake quantities, timing, and (or) partitioning - and the complex interactions of those with specific genotypes (G), management practices (M), and (or) production environments (E). Limited reporting of both N and yield dynamics at plant-component, individual-plant, and community levels has contributed to a considerable knowledge gap as to whether the physiological mechanisms that govern maize plant N dynamics and thei...

Seedborne fungi can reduce survival, growth, and yield of maize (Zea mays L.). Laboratory, field, and growth chamber experiments were conducted to determine the effects of the seed treatment fungicides fludioxonil, mefenoxam, and azoxystrobin on germination, plant population, and grain yield of maize grown from low-quality hybrid seed infected with seedborne fungal pathogens. Study I used seed of four hybrids infected at 0-54% incidence with Fusarium spp., Stenocarpella maydis, Penicillium spp., Rhizopus spp., and/or Aspergillus spp. Study II used three seed lots for each of two hybrids infected at 7-37% incidence with S. maydis. Warm and cold germination for untreated seed varied among hybrids in both studies. Warm germination of the seed lot with the highest incidence of S. maydis in stu...

Root system architecture (RSA) is seldom considered as a selection criterion to improve yield in maize breeding, mainly because of the practical difficulties with their evaluation under field conditions. In the present study, phenotypic profiling of 187 advanced-backcross BC4F3 maize lines (Ye478 × Wu312) was conducted at different developmental stages under field conditions at two locations (Dongbeiwang in 2007 and Shangzhuang in 2008) for five quantitative root traits. The aims were to (1) understand the genetic basis of root growth in the field; (2) investigate the contribution of root traits to grain yield (GY); and (3) detect QTLs controlling root traits at the seedling (I), silking (II) and maturation (III) stages. Axial root (AR)-related traits showed higher heritability than latera...

Abstract The objective of this work was to determine the potential of germplasm from the Germplasm Enhancement of Maize (GEM) programme for use as a biofuel feedstock, relative to commercial grain and silage hybrids. Eighteen maize genotypes including GEM varieties and commercial checks were evaluated in a 2-year field study for dry matter yield, moisture at harvest and sugar produced by hydrolysis of whole plants and cobs. There were no significant correlations between any of the traits measured, suggesting that it should be possible to improve yield with quality traits using a selection index. A brown midrib variety was in the top significance group for hydrolysis traits, underscoring the impact of this mutation on the digestibility of lignocellulosic biomass. Commercial varieties tended...

Addressing concerns about future food supply and climate change requires management practices that maximize productivity per unit of arable land while reducing negative environmental impact. On-farm data were evaluated to assess energy balance and greenhouse gas (GHG) emissions of irrigated maize in Nebraska that received large nitrogen (N) fertilizer (183 kg of N?ha?1) and irrigation water inputs (272 mm or 2,720 m3 ha?1). Although energy inputs (30 GJ?ha?1) were larger than those reported for US maize systems in previous studies, irrigated maize in central Nebraska achieved higher grain and net energy yields (13.2 Mg?ha?1 and 159 GJ?ha?1, respectively) and lower GHG-emission intensity (231 kg of CO2e?Mg?1 of grain). Greater input-use efficiencies, especially for N fertilizer, were responsible for better performance of these irrigated systems, compared with much lower-yielding, mostly rainfed maize systems in previous studies. Large variation in energy inputs and GHG emissions across irrigated fields in the present study resulted from differences in applied irrigation water amount and imbalances between applied N inputs and crop N demand, indicating potential to further improve environmental performance through better management of these inputs. Observed variation in N-use efficiency, at any level of applied N inputs, suggests that an N-balance approach may be more appropriate for estimating soil N2O emissions than the Intergovernmental Panel on Climate Change approach based on a fixed proportion of applied N. Negative correlation between GHG-emission intensity and net energy yield supports the proposition that achieving high yields, large positive energy balance, and low GHG emissions in intensive cropping systems are not conflicting goals.

Balancing productivity, profitability, and environmental health is a key challenge for agricultural sustainability. Most crop production systems in the United States are characterized by low species and management diversity, high use of fossil energy and agrichemicals, and large negative impacts on the environment. We hypothesized that cropping system diversification would promote ecosystem services that would supplement, and eventually displace, synthetic external inputs used to maintain crop productivity. To test this, we conducted a field study from 2003-2011 in Iowa that included three contrasting systems varying in length of crop sequence and inputs. We compared a conventionally managed 2-yr rotation (maize-soybean) that received fertilizers and herbicides at rates comparable to those used on nearby farms with two more diverse cropping systems: a 3-yr rotation (maize-soybean-small grain + red clover) and a 4-yr rotation (maize-soybean-small grain + alfalfa-alfalfa) managed with lower synthetic N fertilizer and herbicide inputs and periodic applications of cattle manure. Grain yields, mass of harvested products, and profit in the more diverse systems were similar to, or greater than, those in the conventional system, despite reductions of agrichemical inputs. Weeds were suppressed effectively in all systems, but freshwater toxicity of the more diverse systems was two orders of magnitude lower than in the conventional system. Results of our study indicate that more diverse cropping systems can use small amounts of synthetic agrichemical inputs as powerful tools with which to tune, rather than drive, agroecosystem performance, while meeting or exceeding the performance of less diverse systems. PMID:23071739

Large amounts of genetically modified grains producing Bacillus thuringiensis (Bt) toxins have been imported to Korea. Therefore, the establishment of a risk assessment system for evaluating the potential impacts of imported Bt maize on non-target insects is important. Before evaluating the environmental impacts of Bt grains of unknown origin, Cry protein types must first be identified in test Bt grains. Cry toxins of imported Bt maize grains were analyzed by ELISA. Because all tested Bt maize grains contained Cry1A, Tenebrio molitor, a non-lepidopteran species, was selected as the non-target insect species. A domestic maize strain that showed few differences in nutritional composition compared to the Bt maize grain was used as the alternative non-Bt control. Slightly increased survival ra...

Agricultural lime, natural zeolite (clinoptilolite), hydroxyapatite, and an iron oxide waste byproduct (Fe-rich, a trademark name of E.I. du Pont de Nemours) were added to an artificially contaminated Applying silt loam soil to stabilize and limit the uptake of Zn by crops. A greenhouse pot study involves spiking the soil with flue dust FD at 0, 150, 300, 600, 1200, and 2400 mg of Zn kg{sup -1}. As much as 40% of the total Zn occurred in an exchangeable form, the form considered most bioavailable to plants, when the pH of the FD-spiked soil was below 6.0. The ameliorants (lime, zeolite, apatite, and Fe-rich) decreased the concentration of the exchangeable form of Zn at each level of FD in soil; however, the largest decrease occurred with the lowest dose. Maize (Zea mays), barley (Hordeum vulgare), and radish (Raphanus sativus) were growth to determine the effects of Zn on the plant growth and its uptake. The addition of ameliorants to soil enhanced the growth and yield of maize and barley, but only Fe-rich enhanced the growth of radish at all FD rates. Lime, zeolite, and apatite significantly reduced the Zn concentration in tissues of the 3-week-old maize, in mature maize tissues (roots, young leaves, old leaves, stems, grain), and in barley. The largest reduction (over 80%) in Zn uptake by all crops was effected by Fe-rich, which is consistent with the greatest reduction in soil-exchangeable Zn by this ameliorant. 44 refs., 4 figs., 7 tabs.

Synthetic elicitors can be used to induce resistance in plants against pathogens and arthropod herbivores. Such compounds may also change the emission of herbivore-induced plant volatiles, which serve as important cues for parasitic wasps to locate their hosts. Therefore, the use of elicitors in the field may affect biological control of insect pests. To test this, we treated maize seedlings growing in a subtropical field in Mexico with methyl jasmonate (MeJA), an elicitor of defense responses against many insects, and benzo-(1,2,3)-thiadiazole-7-carbothioic acid S-methyl ester (BTH), an elicitor of resistance against certain pathogens. Volatile emission, herbivore infestation, pathogen infection, and plant performance (growth and grain yield) of treated and untreated maize plants were mea...

The generation of biogas on the basis of renewable primary products is gaining increasingly in importance in agriculture. While manure, organic residues and waste from agricultural businesses and farms as well as bio-waste were predominantly used until 2004, the use of field crops (silage and corn) has become more and more important since the EEG has been amended. However, the public discussion is focusing almost only on the utilization of maize as co-substrate, although in Thuringia they evidently use a much wider mix of substrates which is geared to the conditions of the agricultural businesses. Maize silage and corn have a similar share in the formation of gas. Monofermentation is gaining increasingly in importance, not least due to the innovation bonus. This is why maize, the fodder plant, is used as substrate in many of these plants. The advantages of maize are its high yield potential, its favorable technological suitability, the good conservative properties and the different options to use it as silage and as grain. Welted silage is used to a much lesser extent, as is whole plant silage at the moment. If biogas plants were to look at maize silage as a substrate, the silage quality would obviously become more and more important, since silage losses and the silage quality have definitely an impact on the commercial success of the biogas plant. Since biogas plants respond vehemently to fluctuations in quality, silage that is rich in nutrients, easily digestible and free from mold is a fundamental prerequisite for a high gas yield. Reheating and silage with a reduced quality are tantamount to high losses, although the mere loss in quantity must not be underrated, either. This paper is meant to show what factors will have an impact on the silage quality and to prove various approaches how to ensure a stable quality. Moreover, the impact improper procedures applied during the process of making silage will have on the commercial success of the generation of biogas will also be highlighted. (orig.)

Abstract in portuguese O cultivo em aléias tem sido recomendado como alternativa para a substituição da agricultura de corte e queima, no trópico úmido, devido à grande capacidade de produção de matéria orgânica e de reciclagem de nutrientes, mas algumas dúvidas quanto à sustentabilidade e à competição interespecífica são persistentes. O objetivo no trabalho foi avaliar a viabilidade da cultura do milho em um sistema de cultivo em aléias de leguminosas arbóreas. O delineament (more) o experimental utilizado foi em blocos casualisados, com quatro repetições dos tratamentos: aléias de sombreiro (Clitoria fairchildiana), ingá (Inga edulis), guandu (Cajanus cajan) e leucena (Leucaena leucocephala) e uma testemunha sem aléias. Foram avaliadas a remobilização de carbono e nitrogênio, massa de grãos, massa de mil grãos e competição interespecífica entre as cultivares de milho e as leguminosas. A produção de grãos foi maior nas parcelas com C. fairchildiana e L. leucocephala. A produtividade do híbrido de milho foi superior à da variedade em todos os tratamentos. A produtividade e a massa de mil grãos de milho não são negativamente afetadas pela distância da linha da leguminosa arbórea. Esse estudo conclui que o sistema de aléias com leguminosas arbóreas é uma alternativa importante ao manejo sustentável dos agroecossistemas no tropico úmido. Além disso, nessa região a produtividade em grãos na cultura do milho é favorecida no sistema de aléias preeestabelecidas com as leguminosas arbóreas sombreiro, ingá e leucena e pela utilização de genótipos eficientes no aproveitamento do nitrogênio, cujo sincronismo entre a liberação e a absorção do N aplicado por meio das leguminosas deve ser aprimorado. Abstract in english Alley cropping has been recommended as alternative land use to slash-and-burn agriculture in humid tropics. However, interespecific competition between cash crop and hedgerow can reduce this potential. This study aimed to evaluate the feasibility of maize crop in a leguminous tree alley cropping. A random block experimental design was adopted, with four replicates and five treatments: alleys of "sombreiro" (Clitoria fairchildiana), inga (Inga edulis), pigeon pea (Cajanus (more) cajan), and leucaena (Leucaena leucocephala) and a control treatment without alley. C and N partitioning, grain yield, 1000 grain mass and interspecifics competition between maize varieties and legume hedgerows were evaluated. Grain yield was higher for C. fairchildiana and L. leucocephala treatments. The grain yield of hibrid maize was higher than that of maize variety at all treatments. The grain yield and 1000 grain mass maize was not affected by distance of legume hedgerows. This study concluded that the alley cropping with leguminous tree is an important alternative to the sustainable management of agroecosystems in humid tropics. Furthermore, in this region, the productivity of maize grain is favored in alley cropping with leguminous trees, like sombreiro, inga and leucena by genotypes efficient in the use of nitrogen, whose timing between its release and absorption when applied by means of pulses, must be enhanced.

Maize is one of the most important crops worldwide, and in Brazil, the state of Paraná stands as its largest producer. The crop demands high inputs of N fertilizers, therefore all strategies aiming to optimize the grain production with lower inputs are very relevant. Endophytic bacteria have a high potential to increment maize grain yield by means of input via biological nitrogen fixation and/or plant growth promotion, in this last case increasing the absorption of water and nutrients by the plants. In this study, we established a collection of 217 endophytic bacteria, isolated from roots of four lineages and three hybrid genotypes of maize, and isolated in four different N-free culture media. Biochemical-comprising growth in different carbon sources, intrinsic tolerance to antibiotics, and biochemical tests for catalase, nitrate reductase, urease, and growth in N-free media in vitro-and genetic characterization by BOX-PCR revealed great variability among the isolates. Both commercial hybrids and homozygous lineages were broadly colonized by endophytes, and sequencing of the 16S rRNA gene revealed the presence of bacteria belonging to the genera Pantoea, Bacillus, Burkholderia, and Klebsiella. Qualitative differences in endophytic colonization were detected between lineages and hybrid genotypes. PMID:22956211

Abstract in portuguese O peso de grãos é um dos componentes determinantes do rendimento de grãos de milho, que apresenta relações complexas com várias características morfológicas da espiga. O objetivo deste trabalho foi verificar como o peso dos grãos das espigas de milho está relacionado diretamente ou indiretamente com as características morfológicas das espigas e se esta relação depende do tipo de híbrido: simples, triplo ou duplo. O experimento de milho foi realizado no ano (more) agrícola de 2004/05, na Universidade Federal de Santa Maria, com seis tratamentos, que foram compostos de dois híbridos simples, dois híbridos triplos e dois híbridos duplos. O delineamento utilizado foi o de blocos completos ao acaso, com três repetições, com parcelas de duas filas de cinco metros de comprimento com 0,8 m entre filas e densidade de 55.000 plantas ha-1. As correlações entre as características morfológicas da espiga e o peso de grãos foram desdobradas em efeitos diretos e indiretos. O número de filas de grãos por espiga está correlacionado com o peso de grãos apenas nos híbridos duplos (0,5298), e esta correlação se deve ao efeito indireto positivo do número de grãos por espiga (0,8875) e negativo do peso de 100 grãos (- 0,3795). A seleção de espigas com maior peso de 100 grãos e maior número de grãos por espiga tem efeito direto sobre o aumento do peso de grãos por espiga nos híbridos simples e triplo, enquanto que, no híbrido duplo, apenas o número de grãos por espiga tem efeito. As relações entre as características de espigas são dependentes dos genótipos, o que deve complicar um pouco mais a tarefa dos melhoristas de plantas ao selecionar genótipos para maior peso de grão por espiga. Abstract in english The weight of grains is one of the decisive components of the income of corn yield, and presents complex relationships with several morphologic characteristics of the maize spikes. The objective of this research was to verify if the grain weight of the maize spikes is related directly or indirectly with the morphologic characteristics of the spikes and if this relationship depends on the type of hybrid: single, triple or double. The maize experiment was accomplished in th (more) e year 2004/2005, in Santa Maria?s Federal University, with six treatments, that were composed of two single hybrids, two triple hybrids and two double hybrids. The experiment design was a randomized complete block with three replications. The plot was of two lines with five meters length with 0.8m between lines and density of 55,000 plants ha-1. The correlations between the morphologic characteristics of the maize spikes and the weight of grains were outspread in direct and indirect effects. The number of grains lines by spike is correlated with grains weight just in the double hybrid (0.5298) and this correlation is due to the positive indirect effect of the number of grains by spike (0.8875) and negative for weight of 100 grains (-0.3795). The selection of spikes with larger weight of 100 grains and larger number of grains by spike has direct effect on the increase of the grain weight by spike for single and triple hybrid, but in the double hybrid, the number of grains by spike just has direct effect on grains weight. The relationships among the maize spikes characteristics are dependent of the genotypes, what should complicate a little more the job of the crop breeding when selecting genotypes for larger grain weight by spike.

Abstract Plant height (PH), ear height (EH) and the PH/EH ratio have a great effect on plant lodging in maize (Zea mays L.) under intensive cropping systems. To understand the genetic mechanisms controlling PH, EH and the PH/EH ratio in response to nitrogen (N) or phosphorus (P) supply, a set of 218 recombinant inbred lines (RILs) was used to evaluate PH, EH, PH/EH ratio and grain yield (GY) and grain yield components under low N, low P and normal N and P supply (NP). A total of 100 QTLs (quantitative trait loci) were detected for the traits investigated. Several QTLs were found to be associated with PH (bin 1.06/1.07) only, both PH and EH (umc1692 at bin 5.01/5.03; umc2313-umc1006 at bin 6.02) and the PH/EH ratio (bnlg1484-bnlg1866 at bin 1.03; umc1164-um1757 at bin 4.01) which was also a...

For economic as well as environmental reasons, the determination of optimal nitrogen (N) fertiliser application rates under field conditions is of great importance, especially under irrigated conditions. A two-year field experiment was conducted in Hungary (47^o33'N, 21^o26'E, 111m) with six N fertiliser rates (0-150kgha^-^1) under irrigated and non-irrigated conditions with the aim to compare the chlorophyll (Chl) concentration of maize (Zea mays L.) leaves at different growth stages to the soil nitrate-N, the amount of N applied as fertilizer and grain yield. The effect of irrigation and N fertilisation on the soil water and nitrate-N dynamics, grain yield and water use efficiency (WUE) was also examined. In the drought year of 2007, the volumetric soil water content increased from the s...

Maize silage (Zea mays) comprises an increasing proportion of US Midwestern dairy cow rations. A weakness of maize silage is its lower protein levels; however, maize silage protein and biomass yield might be enhanced by intercropping with legumes. This study examined forage quality and dry matter pe...

Maize (Zea mays L.) stover has been identified as an important feedstock for the production of cellulosic ethanol. Our objectives were to measure hybrid effect and combining ability patterns of traits related to cellulosic ethanol production, determine if germplasm and mutations used for silage production would also be beneficial for feedstock production, and examine relationships between traits that are relevant to selective breeding. We evaluated grain hybrids, germplasm bred for silage production, brown-midrib hybrids, and a leafy hybrid. Yield and composition traits were measured in four environments. There was a 53% difference in stover yield between commercial grain hybrids that were equivalent for other production-related traits. Silage germplasm may be useful for increasing stover yield and reducing lignin concentration. We found much more variation among hybrids than either in vitro ruminal fermentability or polysaccharide concentration. Correlations between traits were mostly favorable or nonexistent. Our results suggest that utilizing standing genetic variation of maize in breeding programs could substantially increase the amount of biofuels produced from stover per unit area of land.

Low phosphate availability is a major constraint on plant growth and agricultural productivity. Engineering a crop with enhanced low phosphate tolerance by transgenic technique could be one way of alleviating agricultural losses due to phosphate deficiency. In this study, we reported that transgenic maize plants that overexpressed the Thellungiella halophila vacuolar H+-pyrophosphatase gene (TsVP) were more tolerant to phosphate deficit stress than the wild type. Under phosphate sufficient conditions, transgenic plants showed more vigorous root growth than the wild type. When phosphate deficit stress was imposed, they also developed more robust root systems than the wild type, this advantage facilitated phosphate uptake, which meant that transgenic plants accumulated more phosphorus. So the growth and development in the transgenic maize plants were not damaged as much as in the wild type plants under phosphate limitation. Overexpression of TsVP increased the expression of genes involved in auxin transport, which indicated that the development of larger root systems in transgenic plants might be due in part to enhanced auxin transport which controls developmental events in plants. Moreover, transgenic plants showed less reproductive development retardation and a higher grain yield per plant than the wild type plants when grown in a low phosphate soil. The phenotypes of transgenic maize plants suggested that the overexpression of TsVP led to larger root systems that allowed transgenic maize plants to take up more phosphate, which led to less injury and better performance than the wild type under phosphate deficiency conditions. This study describes a feasible strategy for improving low phosphate tolerance in maize and reducing agricultural losses caused by phosphate deficit stress. PMID:20980094

Abstract in portuguese O nitrogênio é o nutriente exigido em maior quantidade pela cultura do milho, sendo o que mais frequentemente limita a produtividade de grãos. O objetivo do trabalho foi avaliar, em área com vinte anos (1985-2005) de estudo de sistemas de manejo de solo, na Universidade Estadual Paulista, Campus de Botucatu (SP), a resposta do milho à produtividade, características agronômicas e eficiência de uso de nitrogênio (N), em função da adubação nitrogenada em cobertu (more) ra, nos sistemas de preparo convencional e plantio direto. O delineamento experimental utilizado foi o de blocos casualizados, em esquema de parcelas subdivididas, com quatro repetições. As parcelas foram representadas por preparo convencional do solo e plantio direto e as subparcelas por doses de adubação nitrogenada em cobertura (0 kg ha-1, 40 kg ha-1, 80 kg ha-1, 120 kg ha-1 e 160 kg ha-1). A adubação nitrogenada de cobertura promoveu acréscimos significativos nas características agronômicas e nutricionais do milho, com a produtividade máxima de grãos obtida com 151 kg ha-1 de N. Nas doses de 90 kg ha-1 e 145 kg ha-1 de N em cobertura, os valores da eficiência agronômica e de recuperação foram semelhantes, para o preparo convencional do solo e plantio direto, respectivamente. As produtividades de grãos e as características agronômicas e nutricionais do milho não foram afetadas pelo tipo de preparo do solo. Abstract in english Nitrogen is the nutrient most required by the maize crop, being often the most limiting one to grain yield. This research aimed to evaluate maize response to yield, agronomic traits, and efficiency of nitrogen (N) use, in relation to nitrogen topdressing, under conventional and no-tillage systems, in an area where soil management systems have been studied for twenty years (1985-2005), in the Universidade Estadual Paulista, in Botucatu, São Paulo State, Brazil. The experi (more) mental design was randomized blocks, in a split-plot arrangement, with four replications. The plots consisted of conventional and no-tillage systems and the subplots comprised topdressing nitrogen doses (0 kg ha-1, 40 kg ha-1, 80 kg ha-1, 120 kg ha-1, and 160 kg ha-1). The nitrogen topdressing promoted significant increases in maize agronomic and nutritional traits, with maximum grain yield obtained with 151 kg ha-1 of N. For the 90 kg ha-1 and 145 kg ha-1 nitrogen topdressing doses, the agronomic and recovery efficiency values were similar, when considered the conventional and no-tillage systems, respectively. The grain yield and maize agronomic and nutritional traits were not affected by soil management system.

Abstract in portuguese O interesse em reduzir o espaçamento entre linhas do milho tem aumentado nas regiões brasileiras com estação estival de crescimento reduzida, devido a vantagens potenciais, tais como a maior eficiência de uso da radiação solar. Este experimento foi realizado para avaliar o efeito da redução de espaçamentos entre linhas no rendimento de grãos, em diferentes épocas de semeadura e cultivares de milho. O experimento foi conduzido em Lages, SC, durante os anos agr? (more) ?colas de 1996/97 e 1997/98, em delineamento de parcelas sub-subdivididas. Uma época de semeadura antecipada (1º de outubro) e uma normal (15 de novembro) foram testadas na parcela principal; duas cultivares morfologicamente contrastantes (híbrido simples superprecoce e híbrido duplo tardio foram utilizados nas subparcelas e três espaçamentos entrelinhas (100, 75 e 50 cm) foram usados nas sub-subparecelas. A redução do espaçamento de 100 para 50 cm aumentou linearmente o rendimento de grãos. Os aumentos no rendimento obtidos pela utilização de menor espaçamento entre linhas foram maiores na semeadura antecipada. O tipo de arquitetura da planta e o ciclo do híbrido utilizado não interferiram na resposta do milho à redução do espaçamento entre linhas. Abstract in english The interest in reducing maize row spacing in the short growing season regions of Brazil is increasing due to potential advantages such as higher radiation use efficiency. This experiment was conducted to evaluate the effect of row spacing reduction on grain yield of different maize cultivars planted at different dates. The trial was conducted in Lages, in the State of Santa Catarina, Brazil, during 1996/97 and 1997/98 growing seasons, in a split-split plot design. Early (more) (October 1st) and normal (November 15) planting dates were tested in the main plot; two morphologically contrasting cultivars (an early single-cross and a late double-cross hybrids) were evaluated in the split plots and three row widths (100, 75 and 50 cm) were studied in the split-split plots. The reduction of row spacing from 100 to 50 cm increased linearly maize grain yield. The yield edge provided by narrow rows was higher when maize was sown earlier in the season. Differences in hybrid cycle and plant architecture did not alter maize response to the reduction of row spacing.

ABSTRACT Physical properties and proximate compositions of genetically improved maize grains (TZRS-White) and local Tiv maize grain variety were characterized. The grains were steeped in water (1:4, w/v) for 0 h, 12 h, 24 h, 48 h and 72 h at 30 +- 2C. The steeped grains were analyzed for proximate composition and microbial load, while the steep water was analyzed for pH, titratable acidity, soluble solids and microbial load. Genetically improved maize variety (TZRS-W) was found to be of harder endospermic structure. For both grain varieties, significant differences (P 0.05) were found in the proximate composition of the nonsteeped grains (0 h steeping) and grains steeped for 12-72 h. Protein quality of grains steeped for 48 h was optimum. Steeping resulted into increases in microbial load ...

Large-scale modeling applications are associated with various assumptions and spatial resolutions. In this study, the GIS-based Environmental Policy Integrated Climate (GEPIC) model was used to examine the effects of resampling input data from a resolution of 5arcmin to 10 and 30arcmin on simulated crop grain yields. Maize cultivation in the USA was used as a case study. The biggest impact was found to be the resampling of land use datasets. Rain-fed and irrigated areas are simulated separately and the yields are subsequently weighted according to irrigated and rain-fed fractions in each grid cell. The aggregation causes some grid cells to become rain-fed and irrigated at coarser resolutions after being only rain-fed or only irrigated at 5arcmin. The estimated yield can increase or decreas...

The theme of this thesis was chosen against the background of the necessary substitution of fossil fuels and the need to reduce greenhouse gas emissions. One major solution for these topics may be the energy generation from domestically produced biomass. The overall aim of this thesis was the identification of one or more efficient energy cropping systems for Central Europe. The existence of diverse production environments necessitates further diversification and the identification of several energy crops and the development of energy cropping systems suited to those diverse environments. This thesis starts with an introductory essay (chapter 1), which provides the background for renewable energy production, its features, demands and potentials, and the scientific basis of this thesis. Chapters 2 to 6 consist of five manuscripts to be published in reviewed journals (Papers I, II, IV and V) or in a multi-author book (Paper III). Subsequently, the results from all papers are discussed in a general setting (chapter 7), from which a general conclusion is formulated (chapter 8). The basis of the research formed four field experiments, which were conducted at the experimental sites Ihinger Hof, Oberer Lindenhof and Goldener Acker of the University of Hohenheim, in south-western Germany. Paper I addresses the overall objective of this thesis. Selected cropping systems for this experiment were short rotation willow, miscanthus, switchgrass, energy maize and two different crop rotation systems including winter oilseed rape, winter wheat and winter triticale with either conventional tillage or no-till. The systems were cultivated with three different nitrogen fertilizer applications. An energy balance was calculated to evaluate the biomass and energy yields of the different cropping systems. Results indicate that perennial lignocellulosic crops combine high biomass and net energy yields with low input and potential ecological impacts. Switchgrass, which produced low yields at the study site, may better perform on marginal sites. Switchgrass is an example of the need to grow site-adapted energy crops. The annual energy crop maize required the highest input, but at the same time yielded the most. The two crop rotation systems did not differ in yield and energy input, but the system with no-till may be more environmentally benign as it has the potential to sequester carbon. The objective of Paper II was the optimization of crop cultivation through the differentiation of input parameters to enhance the quality of the energy crop triticale, without influencing the biomass yield. The intention was to minimize the content of combustion-disturbing elements (potassium and chlorine) and the ash residue of both aboveground plant parts (grain and straw). It was done through different straw and potassium fertilizer treatments. It could be shown that the removal of straw from the previously cultivated crop and no additional potassium fertilizer could reduce the amount of combustion-disturbing elements. A high influence must also be expected from site and weather conditions. Papers III to V address the supply of different high quality biomasses, with the focus on maize for anaerobic digestion. The objective of Paper III was the assessment of the requirements of biogas plants and biomass for anaerobic digestion. It introduces potential energy crops, along with their advantages and disadvantages. Alongside maize, many other biomass types, which are preserved as silage and are high in carbohydrates and low in lignocelluloses, can be anaerobically digested. The development of potential site-specific crop rotation systems for biomass production are discussed. The objective of Papers IV and V was the identification of suitable biomass and production systems for the anaerobic digestion. The focus lay on the determination of (i) suitable energy maize varieties for Central Europe, (ii) optimal growth periods of energy crops, (iii) the influence of crop management on quality parameters and (iv) environmentally benign crop rotation systems. Differently maturing maize varieties were grown in six different crop rotation systems (continuous maize with and without an undersown grass, maize as a main crop partially preceded by different winter catch crops and followed by winter wheat) and tested at two sites. Additional factors were sowing and/or harvest dates. Maize and cumulative biomass yields of the crop rotation systems were compared. Specific methane yield measurements were carried out to evaluate the energy performance of the tested crops. Quality was assessed either by measurements of the dry matter content or by using the near infrared reflectance spectroscopy for the determination of chemical composition. Results indicate that an environmentally benign crop rotation system requires nearly year-round soil cover to minimize nitrogen leaching. This can be achieved through the cultivation of undersown or catch crops and additional main crops alongside maize, such as winter wheat. Late maturing maize varieties can be cultivated at a site where the maize can build adequate dry matter contents due to a long growth period (late harvest date). The energy generation in terms of methane production was primarily dependent on high biomass yields. It could be further shown that the specific methane yield of maize increased with increasing starch content, digestibility and decreasing fiber content. To conclude, selected site-specific energy crops and crop rotation systems, with suitable crop management, (fertilizer and soil tillage) can produce high quality biomass and the highest net energy return. Lignocellulosic biomass can be optimized for combustion. Wet biomass is an optimal substrate for anaerobic digestion. Profitable energy production is characterized by a high land and energy use efficiency and especially high net energy yields. (orig.)

The study evaluates the potential effect of climate change on maize production in Spain, combining climate models, a crop productivity model, a decision support system and a yield-response model. The study was carried out for two agricultural regions that include the largest areas of Spain where maize is grown as a high input crop. The paper combines the output from a crop model with different techniques of analysis. The scenarios used in this study were generated from the output of two General Circulation Models (GCMs): the Goddard Institute for Space Studies model (GISS) and the Canadian Climate Change Model (CCCM). The study also includes a preliminary evaluation of the potential changes in monetary returns taking into account the possible variability of grain yields and prices, using mean-Gini stochastic dominance (MGSD). A yield response model was estimated using simulated data from the crop model. Weather variables are included. Typically, temperature and precipitation are the only weather variables included in these models. However, solar radiation is another important climate factor for plant growth and development and were included in the yield response model.

Abstract in portuguese O objetivo deste trabalho foi avaliar o impacto do deficit hídrico, no rendimento de grãos de milho, e a eficácia da irrigação em todo ciclo e, especificamente, no florescimento. Os dados foram obtidos em dez anos de experimentação, durante os quais doses variáveis de irrigação foram aplicadas por um sistema de aspersão, localizado no centro da área experimental. Foram calculados balanços hídricos, tendo como variáveis a água precipitada (chuva e irrigaç? (more) ?o) e a evapotranspiração máxima do milho. Foram ajustados modelos de regressão para 27 condições hídricas, relacionando-se rendimento de grãos com deficit hídrico e razão evapotranspiração real sobre evapotranspiração máxima (ETr/ETm). A maior redução na produção ocorre em conseqüência do deficit hídrico na polinização, formação do zigoto e desenvolvimento inicial do grão, numa relação quadrática. Nesse período, a razão ETr/ETm explica quase 80% das variações na produção de grãos, que se estabiliza acima de uma razão de 0,7. A irrigação aumenta e estabiliza a produção do milho; doses de rega de aproximadamente 60% daquela necessária para elevar a umidade do solo à capacidade de campo aumentam a eficiência de uso da irrigação. Abstract in english The objective of this work was to evaluate the impact of water deficit on maize grain yield, as well as the irrigation effectiveness, considering all the crop cycle and, specifically, the flowering period. Data were collected during ten years in several experiments, in which variable doses of irrigation were applied by an aspersion system located in the center of the experimental area. Water balances were calculated, and the precipitated water (rainfall and irrigation) an (more) d the maximum evapotranspiration of the maize were considered as inputs. Models of regression for 27 water conditions were adjusted, relating grain yield to water deficit and actual evapotranspiration to maximum evapotranspiration ratio (ETr/ETm). The highest reduction on grain production occurred in consequence of the water deficit during pollination, zygote formation and initial development of the grain, with a quadratic relation. For this period, the ratio ETr/ETm explains almost 80% of the variations in grain yields, stabilizing over a ratio of 0.7. The irrigation increases and stabilizes the maize production; doses of irrigation of approximately 60% of that necessary to rise soil moisture up to field capacity increase the efficiency of use of the irrigation.

The genetic basis of heterosis in maize has been investigated in a number of studies but results have not been conclusive. Here, we compare quantitative trait loci (QTL) mapping results for grain yield, grain moisture, and plant height from three populations derived from crosses of the heterotic pattern Iowa Stiff Stalk Synthetic??Lancaster Sure Crop, investigated with the Design III, and analyzed with advanced statistical methods specifically developed to examine the genetic basis of mid-parent heterosis (MPH). In two populations, QTL analyses were conducted with a joint fit of linear transformations Z 1 (trait mean across pairs of backcross progenies) and Z 2 (half the trait difference between pairs of backcross progenies) to estimate augmented additive and augmented dominance effects o...

Abstract in portuguese Alterações morfo-fisiológicas introduzidas nos híbridos modernos de milho sugerem mudanças na dinâmica de absorção do nitrogênio, aumentando a habilidade da planta de absorvê-lo durante o enchimento de grãos. Isto pode justificar a utilização de coberturas nitrogenadas tardias sempre que restrições climáticas impedirem o suprimento adequado de nitrogênio durante o desenvolvimento vegetativo da cultura. Este estudo foi conduzido objetivando avaliar os efei (more) tos da fertilização nitrogenada no emborrachamento e espigamento no rendimento e teor de proteína nos grãos de híbridos de milho. Dois experimentos foram instalados em Eldorado do Sul, RS, nos anos agrícolas de 2001/2002 e 2002/2003. Em 2001/2002, os tratamentos foram compostos por dois híbridos (Agroceres 303 e Pioneer 32R21), três doses de N aplicadas durante o desenvolvimento vegetativo (30, 80 e 130 kg ha-1) e três doses de N aplicadas no espigamento (0, 50 e 100 kg ha-1). Em 2002/2003, quatro híbridos (Agroceres 303, Pioneer 32R21, Dekalb 215 e Syngenta Penta) e quatro doses de N aplicadas no espigamento (0, 50, 100 e 150 kg ha-1) foram testadas. A fertilização nitrogenada no emborrachamento e espigamento promoveu incrementos significativos no rendimento e teor de proteína bruta dos grãos. A resposta do rendimento de grãos à cobertura nitrogenada tardia diferiu entre as cultivares. O impacto da fertilização nitrogenada no espigamento foi maior quando se aplicou baixas doses de N na fase de desenvolvimento vegetativo. Os aumentos no rendimento de grãos obtidos com coberturas tardias deveram-se principalmente ao maior peso de grãos. Os híbridos contemporâneos são capazes de absorver N depois do espigamento, contradizendo a hipótese de que coberturas nitrogenadas tardias não são eficientes para aumentar o rendimento de grãos do milho. Abstract in english Physiological changes incorporated into current maize hybrids suggest the occurrence of modifications in the nitrogen uptake dynamics, improving plant ability to uptake N during grain filling. This may justify late N side-dressing whenever environmental constraints prevent adequate nitrogen supply during crops vegetative development. This study evaluates effects of nitrogen fertilization at booting and silking on grain yield and kernel crude protein contents of commercial (more) maize hybrids. Two experiments were set up in Eldorado do Sul, RS, during the 2001/2002 and 2002/2003 growing seasons. In 2001/2002, treatments were composed of two hybrids (Agroceres 303 and Pioneer 32R21), three nitrogen rates applied during maize vegetative development (30, 80 and 130 kg ha-1) and three nitrogen rates applied at silking (0, 50 and 100 kg ha-1). In 2002/2003, four hybrids (Agroceres 303, Pioneer 32R21, Dekalb 215 and Syngenta Penta) and four nitrogen rates side-dressed at booting (0, 50, 100 and 150 kg.ha-1) were assessed. There were significant increments in grain yield and kernel crude protein content with nitrogen fertilization at booting and silking. Grain yield response to late N side-dressing differed among cultivars. The impact of nitrogen fertilization at silking was higher at the smallest rate of N during the plant vegetative development. Enhancements in grain yield with late N side-dressing resulted from increases in grain weight. Modern hybrids can uptake nitrogen during silking, contradicting the hypothesis that late N side-dressing is not efficient to improve maize grain yield.

Abstract in portuguese O objetivo deste trabalho foi estudar o controle genético da produtividade de grãos (PG) e da eficiência no uso de nitrogênio (EUN, produção de grãos/N aplicado) e seus componentes primários - eficiência de absorção (EAbN, N absorvido/N aplicado) e utilização (EUtN, produção de grãos/N absorvido) -, em milho cultivado em ambientes com alta e baixa disponibilidade de nitrogênio. Trinta e um genótipos de milho (28 cruzamentos entre híbridos comerciais e t (more) rês testemunhas) foram avaliados em solos com alta e baixa doses de aplicação de N. Houve redução de 23,2% na média de PG em milho cultivado em solo com baixo teor de N, em relação à obtida com alto N. Com baixo teor de N no solo, observaram-se aumentos de 26,5, 199 e 400% em EUtN, EAbN, e EUN, respectivamente. Em milho cultivado em solo com alto teor de N, as capacidades geral (CGC) e específica (CEC) de combinação foram significativas em PG, EUN e EAbN. Em milho de solos com baixo teor de N, apenas a CGC, na EAbN, foi significativa. A CGC e a CEC não foram significativas, em nenhum dos ambientes, na EUtN. Efeitos genéticos aditivos e não aditivos são responsáveis pelo controle genético da EUN e PG, em milho cultivado em solos com elevada disponibilidade de N, mas os efeitos aditivos são mais importantes. Abstract in english The objectives of this work were to study the genetic control of grain yield (GY) and nitrogen (N) use efficiency (NUE, grain yield/N applied) and its primary components, N uptake efficiency (NUpE, N uptake/N applied) and N utilization efficiency (NUtE, grain yield/N uptake), in maize grown in environments with high and low N availability. Experiments with 31 maize genotypes (28 hybrid crosses and three controls) were carried out in soils with high and low N rates, in the (more) southeast of the state of Minas Gerais, Brazil. There was a reduction of 23.2% in average GY for maize grown in soil with low N, in comparison to that obtained with high N. There were 26.5, 199 and 400% increases in NUtE, NUpE, and NUE, respectively, for maize grown with low N. The general combining ability (GCA) and specific combining ability (SCA) were significant for GY, NUE and NUpE for maize grown in high N soil. Only GCA was significant for NUpE for maize grown in low N soil. The GCA and SCA for NUtE were not significant in either environment. Additive and non-additive genetic effects are responsible for the genetic control of NUE and GY for maize grown in soils with high N availability, although additive effects are more important.

Abstract in spanish El objetivo fue comparar el rendimiento de materia seca y el valor nutritivo de un híbrido convencional de sorgo [(Sorghum bicolor (L.)], establecido a dos distancias entre surcos, con un híbrido convencional de maíz (Zea mays L.). El sorgo var. Solarius fue establecido a 75 y 20 cm entre surcos, y el maíz var. Anjou 387 a 75 cm (siembra convencional) en 2007, 2008 y 2009 en Lusignan, Francia. El rendimiento de materia seca (RMS) en ambas especies declinó con los añ (more) os y esta disminución fue mayor en maíz. El RMS para 2009 fue menor en 20.7, 6.5 y 5 t ha-1, al compararlo con 2007, con respecto a maíz, sorgo 75 y 20 cm, lo que indica que la reducción de lluvia afectó menos el RMS del sorgo 20-cm. Al promediar los años, sorgo 20-cm tuvo mayor proteína con 104.1 g kg-1 MS vs 89.4 y 70.5 g kg-1 MS de sorgo 75-cm y maíz, respectivamente. El maíz tuvo más alta digestibilidad que el promedio de los dos tratamientos de sorgo con 692 vs 636 g kg-1 MS. La digestibilidad fue mayor en maíz debido a su menor concentración de lignina. La concentración en lignina del maíz fue 18 vs 28.8 g kg-1 MS del promedio de los dos tratamientos de sorgo. Sin embargo, la digestibilidad de ambos tratamientos de sorgo aumentó en 77.2 g kg-1 MS al pasar de 2007 a 2009. El maíz fue más sensible a los cambios ambientales. El sorgo sembrado a 20 cm entre surcos fue superior en RMS y en concentración de proteína que el maíz, cuando las condiciones de lluvia son un factor limitante. Abstract in english The purpose of the present study was to compare dry matter yield and nutritive value of conventional hybrid grain sorghum [(Sorghum bicolor (L.)] as influenced by row spacing, with conventional hybrid maize (Zea mays L.). Sorghum hybrid var. Solarius was planted at two distances between rows, 75 and 20 cm, and maize var. Anjou 387 at 75 cm (conventional planting). Dry matter yield (DMY) in both species decreased over the years, being this fall greater in maize. DMY fell b (more) y 20.7, 6.5 and 5 t ha-1 in 2009 when compared to 2007 for maize, sorghum 75 and 20 cm, respectively, indicating that DMY in sorghum 20-cm was less affected by a drop in rainfall than in the other treatments. When averaged over the years, sorghum 20-cm showed the higher protein concentration, 104.1 g kg-1 MS vs 89.4 and 70.5 g kg-1 DM for sorghum 75-cm and maize, respectively. Digestibility in maize was higher than in the average of the two sorghum treatments, 692 vs 636 g kg-1 DM, respectively. Lignin concentration in maize was 18 vs 28.8 g kg-1 DM for the average of the two sorghum treatments. However, digestibility in both sorghum treatments increased by 77.2 g kg-1 MS from 2007 to 2009. Maize was more sensitive to environmental variations. Sorghum planted at 20 cm between rows shows both greater DMY and protein concentration than maize in dry matter yield when rainfall is a limiting factor.

Contamination of maize, Zea mays L., grain with aflatoxin, a naturally occurring toxin produced by Aspergillus flavus, frequently reduces the value and marketability of maize produced in the southern USA. Drought, high temperatures, and insect damage are often associated with high levels of aflatox...

A review. Investigations of the potential of forest biomass, sugarcane, maize, grain sorghum, cannery and industrial wastes, algae, and other agricultural crops for fuel, chemicals and food are discussed. (Refs. 11).

Abstract in portuguese Fertilizantes químicos raramente estão disponíveis aos agricultores com poucos recursos econômicos, e assim o N é, freqüentemente, um elemento mais limitante para a produção de grãos. O objetivo deste trabalho foi quantificar a contribuição da fixação biológica de nitrogênio (FBN) às culturas de amendoim (Arachis hypogaea) e mucuna (Mucuna pruriens), por meio da técnica de abundância natural de 15N e determinar o efeito residual das leguminosas e do pous (more) io sobre o crescimento e acumulação de N em duas variedades de milho. A contribuição da FBN calculada a partir dos dados de delta15N, foi de 40,9, 59,6 e 30,9 kg ha-1, respectivamente, para amendoim, mucuna e o pousio. A única leguminosa de grão colhida foi amendoim que produziu aproximadamente 1,000 kg ha-1. A produtividade da cultura de milho (variedades Caiana e Sol da Manhã) variou de 1,958 a 2,971 kg ha-1 de grãos, sendo mais alta após mucuna em ambas as variedades de milho e após amendoim na Sol da Manhã, seguida por Caiana após amendoim e por último o pousio normal. Para pequenos agricultores o sistema mais atrativo é o que inclui amendoim seguido pelo milho, uma vez que duas colheitas de grãos são possíveis. Contudo, o cálculo do balanço de N indicou que a seqüência amendoim-milho diminuiria, a longo-prazo, a reserva de N do solo, enquanto a seqüência mucuna-milho ajudaria a aumentar a reserva de N do solo. Abstract in english Chemical fertilisers are rarely avaiable to poor farmers, for whom the nitrogen (N) is often the most limiting element for cereal grain production. The objective of this study was to quantify the contribution of biological nitrogen fixation (BNF) to groundnut (Arachis hypogaea) and velvet bean (Mucuna pruriens) crops using the 15N natural abundance (delta15N) technique and to determine their residual effect and that of a natural fallow, on growth and N accumulation by two (more) rustic maize varieties. The contribution of BNF calculated from delta15N data was 40.9, 59.6 and 30.9 kg ha-1, for groundnut, velvet bean and the natural fallow, respectively. The only legume grain harvested was from the groundnut, which yielded approximately 1.000 kg ha-1. The subsequent maize varieties ("Sol de Manhã" and "Caiana Sobralha") yielded between 1.958 and 2.971 kg ha-1, and were higher after velvet bean for both maize varieties and "Sol da Manhã" groundnut, followed by "Caiana" after groundnut and, finally, the natural fallow. For a small-holder producer the most attractive system is the groundnut followed by maize, as, in this treatment, both groundnut and maize grain harvest are possible. However, a simple N balance calculation indicated that the groundnut-maize sequence would, in the long term, deplete soil N reserves, while the velvet bean-maize sequence would lead to a build up of soil nitrogen.

Abstract The European corn borer (Ostrinia nubilalis), the Mediterranean corn borer (Sesamia nonagrioides) and the western corn rootworm (Diabrotica virgifera virgifera) are the main arthropod pests in European maize production. Practised pest control includes chemical control, biological control and cultural control such as ploughing and crop rotation. A pest control option that is available since 1996 is maize varieties that are genetically engineered (GE) to produce insecticidal compounds. GE maize varieties available today express one or several genes from Bacillus thuringiensis (Bt) that target corn borers or corn rootworms. Incentives to growing Bt maize are simplified farm operations, high pest control efficiency, improved grain quality and ecological benefits. Limitations include t...

Abstract The North China Plain (NCP) is the most important agricultural production area in China. Crop production in the NCP is sensitive to changes in both climate and management practices. While previous studies showed a negative impact of climatic change on crop yield since 1980s, the confounding effects of climatic and agronomic factors have not been separately investigated. This paper used 25 years of crop data from three locations (Nanyang, Zhengzhou and Luancheng) across the NCP, together with daily weather data and crop modeling, to analyse the contribution of changes in climatic and agronomic factors to changes in grain yields of wheat and maize. The results showed that the changes in climate were not uniform across the NCP and during different crop growth stages. Warming mainly o...

Efficacy of natural non-toxic materials including extracts of onion and garlic as well as eugenol was tested against aflatoxin production by A. flavus in liquid SMKY medium and in maize grains. Maximum inhibition in the mycelial growth occurred with garlic extract (61.94%), whereas inhibition of aflatoxin production was highest (60.44%) due to onion extract. Eugenol was most suitable for inhibiting aflatoxin production (60.35%) on maize grains. PMID:1512040

Abstract in portuguese O objetivo deste trabalho foi determinar a importância relativa da eficiência de aquisição (EAP - P absorvido por unidade de P no solo) e de utilização interna de fósforo (EUIP - produção de grãos por unidade de P absorvido), sobre a eficiência de uso desse nutriente (EUP - produção de grãos por unidade de P no solo), em 28 genótipos tropicais de milho, avaliados em três ambientes com baixa e dois com alta disponibilidade de P. A eficiência de aquisição (more) de P foi quase duas vezes mais importante que a EUIP, na variabilidade observada em EUP, nos ambientes com baixa disponibilidade de P, e três vezes mais importante naqueles com alta disponibilidade. Programas de melhoramento de milho devem utilizar índices de seleção com peso maior para EAP do que para EUIP, para aumento na EUP. A correlação entre EAP e EUIP não foi significativa em nenhum dos níveis de P. A seleção numa dessas características, portanto, não deve afetar a outra. O principal componente da EUIP foi o quociente de utilização (produção de grãos por unidade de P nos grãos), e não o índice de colheita de P (P nos grãos por unidade de P absorvido). A seleção para reduzir a concentração de P nos grãos deve aumentar o quociente de utilização e conseqüentemente aumentar a EUIP. Abstract in english The objective of this work was to determine the relative importance of phosphorus acquisition efficiency (PAE - plant P uptake per soil available P), and phosphorus internal utilization efficiency (PUTIL - grain yield per P uptake) in the P use efficiency (PUE - grain yield per soil available P), on 28 tropical maize genotypes evaluated at three low P and two high P environments. PAE was almost two times more important than PUTIL to explain the variability observed in PUE (more) , at low P environments, and three times more important at high P environments. These results indicate that maize breeding programs, to increase PUE in these environments, should use selection index with higher weights for PAE than for PUTIL. The correlation between these two traits showed no significance at low or at high P environments, which indicates that selection in one of these traits would not affect the other. The main component of PUTIL was P quotient of utilization (grain yield per grain P) and not the P harvest index (grain P per P uptake). Selection to reduce grain P concentration should increase the quotient of utilization and consequently increase PUTIL.

Abstract in portuguese Altos rendimentos de milho estão relacionados à emergência rápida, completa e regular das plantas. Este trabalho foi conduzido em Lages (SC), com o objetivo de avaliar o efeito da desuniformidade de emergência e da população de plantas sobre o rendimento de grãos de milho. Os tratamentos foram dispostos em delineamento de blocos ao acaso, em parcelas sub-divididas, alocando-se nas parcelas principais quatro populações de plantas (40.000, 60.000, 80.000 e 100.000 (more) plantas.ha-1) e nas subparcelas os tratamentos de desuniformidade de emergência realizados através da variação da data de semeadura em covas adjacentes na linha de plantio, resultando nas seguintes situações de emergência entre plantas vizinhas: 1 - uniforme (0-0-0-0-0); 2 - desuniformidade de 12 dias (0-12-0-12-0); 3 - 19 dias (0-19-0-19-0); e, 4 - 12 e 19 dias (0-12-19-0-12-19). Na situação de emergência uniforme, o aumento da população de plantas até 76.500 plantas.ha-1 incrementou o rendimento de grãos para 12.900kg.ha-1. Nesta população de plantas, a diferença do rendimento de grãos entre as plantas de emergência uniforme e aquelas em desuniformidade foi aproximadamente 2.900kg.ha-1, indicando que sob níveis de rendimento semelhantes, a realização da ressemeadura pode ser uma prática economicamente vantajosa. A desuniformidade de emergência diminuiu o rendimento de grãos de milho e limitou a resposta ao incremento da população de plantas. Abstract in english High maize grain yields are related to a fast, complete and regular plant emergence. This experiment was carried out in Lages, SC, Brazil, with the objective of evaluating the effects of an uneven plant emergence on maize grain yield at different plant populations. A split plot design was used, with the main plots disposed in randomized complete blocks. Four plant populations, equivalent to 40,000, 60,000, 80,000 and 100,000 pl.ha-1 were tested in the main plots. Differen (more) t levels of unevenness in plant emergence were analyzed in the split plots by varying the sowing dates of adjacent hills inside each as it follows: 1 - even emergence (0-0-0-0); 2 - unevenness of 12 days (0-12-0-12); 3 - unevenness of 19 days (0-19-0-19); 4 - unevenness of 12 and 19 days (0-12-19-0-12-19). The increase in plant population up to 76,500 pl.ha-1 enhanced grain yield to 12,900kg.ha-1. At this plant population, the difference in yield grain per hectare among treatments with even and uneven emergence was nearly 2,900kg. This indicates that under similar productivity levels replanting maize may be on economically viable option. Besides reducing grain yield, uneven emergence also limited maize response to the increment in plant population.

Abstract in portuguese A otimização da exploração do ambiente é necessária para a maximização do rendimento do milho. O arranjo de plantas (distribuição espacial e área ocupada pela planta) interage diretamente na competição intraespecífica por fatores do meio. Assim, o objetivo deste trabalho foi comparar as formas de distribuição espacial equidistante entre plantas de milho e o espaçamento de 0,80 metro na entrelinha, em populações de 30000 a 105000 plantas ha-1. O experime (more) nto foi conduzido em área de Nitossolo Vermelho distroférrico, de textura argilosa, em Botucatu (SP), na safra 2007/08. O delineamento experimental foi o de blocos casualizados, e os tratamentos foram combinados em fatorial 2X6 (quatro repetições), em parcelas de 4,5 x 10m. Foram avaliados os caracteres comprimento e diâmetro de espiga e sabugo, comprimento do grão; número de fileiras, massa e número de grãos por espiga, porcentagem de plantas acamadas; número de grãos e de espigas por hectare, índice de espiga, massa de mil grãos e produtividade. Todos os parâmetros avaliados foram influenciados pelas populações e a porcentagem de plantas acamadas pelos arranjos espaciais, com interação para o diâmetro de espiga e de sabugo. De maneira geral, pode-se concluir que as características avaliadas são influenciadas predominantemente pelas densidades populacionais, independentemente do arranjo espacial. Abstract in english The maximization of environmental resources exploration is necessary to maximize maize grain yield. The plant arrangement (spatial arrangement and occupied area by the plant), acts on the intraspecific competition by environmental factors. Thus, the objective of this work was to compare the equidistant plant spacing and 0.80m row width, in populations of 30000 to 105000 plants ha-1. The essay was located in a clay red alfisol area, in the FCA/UNESP-Botucatu-SP, in 2007/08 (more) growing season. The experimental design was a randomized block in four replications, in 4.5 x 10m plots. It was evaluated ear and grain length, ear and cob diameter, number of grain rows and grain weight per ear, a thousand grains weight, ear index, ear and grain number per hectare, plant lodging and grain yield. All parameters evaluated were affected by plant densities and the spatial arrangements affected only the percentage of stalk lodged plants. In these conditions, it can be affirmed that the maize plant was influenced mainly by plant densities, not by plant arrangement.

It has been conjectured that global warming will increase the prevalence of insect pests in many agro-ecosystems. In this paper, we quantitatively assess four of the key pests of maize, one of the most important systems in North American grain production. Using empirically generated estimates of pest overwintering thresholds and degree-day requirements, along with climate change projections from a high-resolution climate model, we project potential future ranges for each of these pests in the United States. Our analysis suggests the possibility of increased winter survival and greater degree-day accumulations for each of the pests surveyed. We find that relaxed cold limitation could expand the range of all four pest taxa, including a substantial range expansion in the case of corn earworm (H. zea), a migratory, cold-intolerant pest. Because the corn earworm is a cosmopolitan pest that has shown resistance to insecticides, our results suggest that this expansion could also threaten other crops, including those in high-value areas of the western United States. Because managing significant additional pressure from this suite of established pests would require additional pest management inputs, the projected decreases in cold limitation and increases in heat accumulation have the potential to significantly alter the pest management landscape for North American maize production. Further, these range expansions could have substantial economic impacts through increased seed and insecticide costs, decreased yields, and the downstream effects of changes in crop yield variability.

Abstract in portuguese A cultura do milho pode sofrer reduções na produção de grãos quando há déficit hídrico no período crítico do ciclo da cultura, que ocorre desde o pendoamento até o início de enchimento de grãos. O objetivo deste trabalho foi estabelecer relações entre o suprimento de água durante o período crítico do milho e a produção de grãos. Experimentos foram conduzidos em Eldorado do Sul, RS (30º5'S; 51º40'W; 40 m altitude), nas safras 1998/1999 e 2002/2003, a (more) nos em que ocorreram os fenômenos La Niña e El Niño, respectivamente. Os dados de rendimento de grãos e seus componentes foram obtidos em experimentos de campo, sob diferentes volumes de aplicação de água via irrigação. A produtividade de grãos foi inversa à média geral do Estado, nos dois anos analisados. Em 1998/1999, durante uma estiagem longa, 46,8 mm de chuva no período crítico garantiram rendimento próximo de 8.000 kg ha-1 sem irrigação. Em 2002/2003 uma curta estiagem no período crítico reduziu a produtividade para menos de 2.000 kg ha-1 no mesmo tratamento, afetando o número de espigas por planta e o número de grãos por espiga. Portanto, em anos de El Niño, mesmo que as previsões climáticas apontem para uma distribuição favorável de chuvas, há risco na produção esperada de milho, se o suprimento de água no período crítico da cultura não for adequado. Abstract in english Maize crops may experience reductions of grain yields when submitted to water deficit during the critical period of crop cycle, from tasseling stage to beginning of grain filling. The objective of this work was to demonstrate the importance of the water supply during the critical period on the grain production of maize. Experiments were conducted in Eldorado do Sul, Brazil (30º5'S; 51º40'W; 40 m altitude), during the crop seasons of 1998/1999 and 2002/2003, characterize (more) d by La Niña and El Niño phenomenon, respectively. Data of grain yield and its components were obtained in field experiments, using different volumes of water applied through irrigation. The grain yields showed an opposite tendency when compared to the regional estimated average. In 1998/1999, during a long drought period, 46.8 mm of rain on the critical period allowed a grain yield of about 8 t ha-1 without irrigation. In contrast, in 2002/2003 a short drought during the critical period reduced the grain yield to less than 2 t ha-1, affecting the number of ear per plant and the number of kernel per ear. Therefore, risks in the expected maize production are probable, although having climatic forecasting of favorable rain distribution in the region, such as by El Niño phenomenon.

Root system architecture (RSA) is seldom considered as a selection criterion to improve yield in maize breeding, mainly because of the practical difficulties with their evaluation under field conditions. In the present study, phenotypic profiling of 187 advanced-backcross BC(4)F(3) maize lines (Ye478 × Wu312) was conducted at different developmental stages under field conditions at two locations (Dongbeiwang in 2007 and Shangzhuang in 2008) for five quantitative root traits. The aims were to (1) understand the genetic basis of root growth in the field; (2) investigate the contribution of root traits to grain yield (GY); and (3) detect QTLs controlling root traits at the seedling (I), silking (II) and maturation (III) stages. Axial root (AR)-related traits showed higher heritability than lateral root (LR)-related traits, which indicated stronger environmental effects on LR growth. Among the three developmental stages, root establishment at stage I showed the closest relationship with GY (r = 0.33-0.43, P < 0.001). Thirty QTLs for RSA were detected in the BC(4)F(3) population and only 13.3 % of the QTLs were detected at stage III. Most important QTLs for root traits were located on chromosome 6 near the locus umc1257 (bin 6.02-6.04) at stage I, and chromosome 10 near the locus umc2003 (bin 10.04) for number of AR across all three developmental stages. The regions of chromosome 7 near the locus bnlg339 (bin 7.03) and chromosome 1 near the locus bnlg1556 (bin 1.07) harbored QTLs for both GY- and LR-related traits at stages I and II, respectively. These results help to understand the genetic basis of root development under field conditions and their contribution to grain yield. PMID:22718302

Abstract in portuguese A importante diminuição nos rendimentos de milho causados pela toxidez produzida pelo alumínio é considerada um dos mais importantes problemas nas regiões tropicais. O melhoramento genético é uma metodologia útil para aumentar os rendimentos do milho em solos ácidos, requerendo um método rápido e seguro que permita diferenciar os diferentes genótipos. O objetivo deste trabalho foi avaliar a possibilidade de utilizar a técnica da coloração com hematoxilina ( (more) HS) na detecção de plântulas tolerantes ao alumínio. Duas populações obtidas de um ciclo de seleção divergente e a original, foram avaliadas depois de sete dias em solução nutritiva utilizando os parâmetros NRG (crescimento líquido da raiz principal) e HS. Os resultados apresentaram uma correlação negativa entre NRG e HS em todas as populações devido ao fato de que as plântulas suscetíveis, caracterizadas por um baixo NRG, apresentaram uma coloração mais intensa do que as tolerantes. Nossos resultados permitem concluir que a técnica de coloração com hematoxilina é um procedimento adequado para selecionar genótipos tolerantes ao alumínio em estado de plântula. Abstract in english A significant decrease in maize grain yield due to aluminum toxicity is considered to be one of the most important agricultural problems for tropical regions. Genetic improvement is a useful approach to increase maize yield in acid soils, but this requires a rapid and reliable method to discriminate between genotypes. In our work we investigated the feasibility of using hematoxylin staining (HS) to detect Al-tolerant plants at the seedling stage. The original population a (more) long with two populations obtained after one cycle of divergent selection were evaluated by net root growth (NRG) and HS after 7 days in nutrient solution. Results showed a negative correlation between NRG and HS in all populations, in which sensitive plants, characterized by low NRG, exhibited more intense staining than tolerant plants. These results indicate that HS is a useful procedure for selecting Al-tolerant maize seedlings.

A six-week experiment was carried out in Benin to evaluate under tropical conditions the variation in nutritional value of soybean and maize grains due to, respectively, environmental factors and the plant variety. Two soybean grains of the same variety (Jupiter) but grown in two agro-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 of metabolisable energy and 27 g of crude protein content were found between varieties of maize. Crude protein content was identical in both soybean grains, while a difference of 16 g/kg DM was found between them in crude fibre content. In spite of these differences in chemical components, there was no significant effect (P>0.05) of the grains' origin or variety on the growth performance of chickens. The daily feed intake, thedaily 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 of this experiment, the environmental factors did not change significantly the nutritional value of soybean grains in chickens' diets. The grain of local variety of white maize were suitable at all ages, whereas the grains of DMR-ESRW were more economic in grower than starter broiler chickens feeding.

Abstract in portuguese Objetivou-se verificar o potencial de 28 híbridos de populações F2 de milho, obtidos de um dialelo completo, juntamente com oito populações F2 parentais e duas testemunhas comerciais quanto a caracteres agronômicos e à heterose e seus componentes. Os experimentos foram desenvolvidos em 2008/2009, em Campinas, Mococa e Palmital, Estado de São Paulo, no delineamento experimental de blocos ao acaso com três repetições. Avaliaram-se os caracteres florescimento masc (more) ulino, altura da espiga e produtividade de grãos, que foi corrigida para 14% de umidade e estande ideal. Efetuaram-se análises de variância individuais e conjuntas, considerando-se o modelo fixo, sendo as médias comparadas pelo Teste de Tukey, além das análises dialélicas pelo modelo de Gardner e Eberhart (1966). Verificaram-se efeitos de heterose e seus componentes altamente significativos. Considerando-se a produtividade de grãos, as populações F2AG8060, F2Fort e F2A2555 foram promissoras em combinações híbridas, com elevados valores de heterose de parental e a F2DAS2B710 com o maior efeito de parental. Houve manifestação de heterose para produtividade de grãos com destaque para o híbrido F2A2555 x F2Fort, confirmando-se o potencial produtivo de híbridos de populações F2 como alternativa para a produção comercial de milho, visando aos produtores de média a baixa tecnologia. Abstract in english The potential of 28 hybrids maize F2 population, obtained from a complete diallel among eight F2 populations, along with the eight parental F2 populations and two commercial controls were evaluated for agronomic traits, heterosis and its components. The experiments were developed in 2008/09, in Campinas, Mococa and Palmital, São Paulo State, Brazil. The experimental design was in randomized blocks, with three replications. The agronomic traits male flowering, ear height (more) and grain yield were evaluated. The grain yield was adjusted to 14% of moisture. Individual and grouped variance analyses were made considering the fixed model, with the means being compared by the Tukey test. The Gardner and Eberhart (1966) model was used in the diallel analysis. It was observed that the effect of heterosis and its components were highly significant. Considering the grain yield, populations F2AG8060, F2Fort, F2A2555 are promising in hybrid combinations, with high values of parental heterosis. The population F2DAS2B710 had the greatest parental heterosis effects. There was heterosis manifestation for grain yield, mainly for hybrid F2A2555 x F2Fort. It was confirmed the potential of F2 population hybrids as an alternative to the commercial maize production with medium to low technological input.

The seasonal distribution of Pratylenchus spp. in seminal and adventitious roots and the relationship of maize yield variables to nematode densities were examined for irrigated maize in sandy soil in 1994 and 1995. Nematode populations in seminal roots were stable or declined (P ? 0.05) during the g...

Systems were designed, simulated and analyzed to assess the economic feasibility of producing ethanol from high-moisture grain, gradually separated from mature whole-plant maize silage. The residual stover fraction containing some grain fines was fed, along with ethanol production by-products (stillage or maize gluten feed), to growing steers. Three systems were compared. In the control, regular maize silage was fed to growing steers with extra maize harvested later and sold as grain for cash. In one alternative (system 2), the separated grain fraction was processed to ethanol and stillage at a local farmer-cooperative plant. In another alternative (system 3), the grain fraction was transferred to a regional industrial plant for wet milling to ethanol, corn gluten-feed and other products. System comparisons were based on estimating gross costs per farm during 1980 to 1982, minus credits for products such as grain maize (control) and ethanol (alternative systems). System 3 was the more attractive alternative. When ethanol was valued at wholesale prices for regular leaded gasoline, these costs were similar in 1981 and 1982 for System 3 and the control. Further refinements of a separation unit, and detailed assessment of the feeding value of the stover fraction plus stillage or corn gluten feed, are warranted. 17 references.

The methane potential of six varieties of fresh maize (whole plant) harvested at three different times and of maize silage (whole plant) in two particle size distributions was experimentally determined in batch assays. Fresh maize gave the highest methane yield/hectare at late harvest (6270 m{sup 3} CH{sub 4} (10{sup 4} m{sup 2}){sup -1}). The methane yield/wet weight (WW) increased from 80 (early harvest) to 137 m{sup 3} CH{sub 4} (t WW){sup -1} (late harvest). Maize harvested at different times, or different varieties of maize had similar specific methane production/volatile solids content (m{sup 3} CH{sub 4} (kg VS){sup -1}). The measured yield m{sup 3} CH{sub 4} (kg VS){sup -1} was 84% of the theoretical methane potential. The estimated ethanol yield was between 2.5 and 3.5 t ethanol (10{sup 4} m{sup 2}){sup -1}. The energy yield was 62 and 19-22 MWh (10{sup 4} m{sup 2}){sup -1} if fresh maize (whole plant) is used for methane or ethanol production respectively. Reducing the particle size of maize silage to an average size of approximately 2 mm increased the methane yield m{sup 3} CH{sub 4} (kg VS){sup -1} by approximately 10%. (author)

In the last three decades, the no-tillage system (NT) has provided environmental and economic advantages for farming in southern Brazil, especially when associated with crop rotation. The objective of this study was to evaluate the effects of different tillage and cropping systems on the grain yields of soybean, maize and wheat, in a 23-year experiment established on an Oxisol in the southern region of Brazil. The experiment was carried out in randomized block experimental design with four replications. The treatments consisted of three tillage systems [NT, NT with chiseling every three years (NTC), and conventional tillage (CT)] and two cropping systems [an annual crop sequence with wheat in the winter and soybean in the summer, designated as crop succession (CS), and a 4-year crop rotati...

Fusarium ear rot caused by Fusarium verticillioides is a prevalent disease in maize which can severely reduce grain yields and quality. Identification of stable quantitative trait loci (QTL) for resistance to Fusarium ear rot is a basic prerequisite for understanding the genetic mechanism of resistance and for the use of marker-assisted selection. In this study, two hundred and ten F 2:3 families were developed from a cross between resistant inbred line BT-1 and susceptible inbred line Xi502, and were genotyped with 178 simple sequence repeat markers. The resistance of each line was evaluated in two environments by artificial inoculation using the nail-punch method. The resistance QTL were detected using the composite interval mapping method. Three QTL were detected on chromosomes 4, 5 and...

This book's contents include: Advances in the genetics of Azospirillum brasilense Sp7: Use of Tn5 mutagenesis for gene mapping and identification; Characterization of DNA segments adjacent to the nifHDK genes of Azospirillum brasilense by Sp7 Tn5 site-directed mutagenesis; Selection at the chemostat of Azospirillum brasilense Cd N/sub 2/-fixing at high O/sub 2/ pressure. Root hair deformation induced on maize and medicago by an Azospirillum transconjugant containing a Rhizobium meliloti nodulation region. Azospirilla are bacteria that live in association with the roots of many grain crops. Since these bacteria bind molecular nitrogen from the air and excrete plant growth substances, interest has focussed on their potential to increase crop yields.

Abstract in portuguese A cultura do milho é sensível ao déficit hídrico, e esta é uma causa freqüente de redução na produção de grãos. O objetivo deste trabalho foi verificar a ocorrência de ajuste osmótico em milho, cultivado em dois sistemas de manejo do solo, com diferentes disponibilidades hídricas. Os tratamentos consistiram do cultivo do milho em semeadura direta (SD) e convencional (SC), com irrigação de forma a manter a umidade do solo próxima à capacidade de campo, e (more) sem irrigação. O ajuste osmótico foi obtido pela diferença do potencial osmótico hidratado entre as plantas irrigadas e sem irrigação. Os maiores valores de potencial mínimo de água na folha ocorreram em plantas cultivadas sob SD, em razão do maior potencial matricial da água no solo nesse sistema. O potencial de pressão e o osmótico hidratado diminuíram em conseqüência do déficit hídrico, o que determinou a ocorrência de ajuste osmótico em ambos os sistemas, que foi mais intenso em manejo convencional. Portanto, o potencial mínimo de água na folha demonstra ser um indicador adequado da condição hídrica das plantas de milho. A cultura apresenta tolerância ao déficit hídrico por meio do mecanismo de ajuste osmótico. Abstract in english Maize is a very sensible crop to water deficit, which is a frequent cause of reduction in its grain yield. The objective of this work was to verify the occurrence of osmotic adjustment in maize cultivated in different soil management systems and water availability. The maize was cropped in no-tillage (NT) and conventional tillage (CT), with irrigation and no-irrigation. For measurements of minimum leaf water potential, a pressure chamber was utilized. Osmotic adjustment w (more) as calculated as the difference between osmotic potentials at full turgor, in irrigated and non-irrigated plants. Highest values of minimum leaf water potential were found in plants cropped in NT, as a response to the highest soil potential on this cropping system. Pressure potential and the osmotic potential at full turgor were reduced as a response to water deficit, resulting on an osmotic adjustment in both cropping systems, with a highest intensity in the CT system. Minimum leaf water potential showed sensitivity to water deficit, which makes it a good indicator of plant water status on maize. Maize crop showed tolerance to water deficit through the mechanism of osmotic adjustment.

Two liquid and one dry pre-commercial release spinosad formulations were evaluated at the labeled rate of 1?ppm against five stored-grain insect species on wheat, short-grain rice, long-grain rice, and maize. Except on maize, efficacy of spinosad was compared with a currently registered grain protectant, chlorpyrifos-methyl (3?ppm) plus deltamethrin (0.5?ppm). The 7- and 14-day mortalities of the lesser grain borer, Rhyzopertha dominica, were 99.0?100.0% on spinosad and chlorpyrifos-methyl plus deltamethrin-treated wheat, short-grain rice, and long-grain rice. Adult progeny of R. dominica after 42?days on these commodities decreased by 99.7?100.0% relative to progeny production on untreated wheat. Mortality and reduction in adult progeny of the rice weevil, Sitophilus oryzae, on the three ...

Abstract in portuguese A monocultura do milho é uma prática comum em algumas regiões do Brasil, sendo responsável pelo incremento dos danos causados pelas doenças. O objetivo deste trabalho foi avaliar o efeito de diferentes sistemas de produção de milho contrastantes quanto ao investimento em manejo sobre a incidência de podridões do colmo, grãos ardidos e produtividade de grãos. Foram testados quatro sistemas: S1 (baixo nível de manejo), S2 (médio), S3 (alto) e S4 (proposto para (more) maximizar o produtividade). Os níveis de manejo diferiram quanto à densidade de semeadura, espaçamento entre linhas, quantidade de fertilizantes e uso da irrigação. Em cada sistema, foram utilizadas três genótipos de milho: BRS Planalto (variedade de polinização aberta), Traktor (híbrido duplo) e P32R21 (híbrido simples). Os experimentos foram conduzidos nas safras 2002/03 e 2003/04, em área de plantio direto e monocultura, sob sucessão de cobertura morta de aveia preta+ervilhaca. O delineamento experimental foi em blocos casualizados, com parcelas subdivididas e quatro repetições. Nas duas safras agrícolas, a variedade Planalto apresentou maior incidência de podridões do colmo do que os híbridos em todos os sistemas de manejo. O fungo Colletotrichum graminicola foi o principal patógeno associado às podridões do colmo. A produtividade de grãos oscilou entre 3.986 a 13.489kg ha-1 em 2003 e entre 1.787 a 13.849kg ha-1 em 2004, variando conforme o genótipo e o sistema de produção. As maiores produtividades foram obtidas em S4 com a utilização do híbrido simples P32R21. A incidência de grãos ardidos nas duas safras foi baixa, não atingindo em nenhum tratamento o valor de 6% considerado no desconto. O fungo Fusarium verticillioides foi o principal patógeno associado aos grãos ardidos. Por outro lado, C. graminicola não foi detectado nos grãos ardidos, demonstrando que sua alta incidência nos colmos não significa sua presença nos grãos. Não foi possível identificar um sistema de manejo que reduzisse a incidência de podridões do colmo e grãos ardidos na cultura do milho. Abstract in english Maize monoculture is an usual practice in some regions of Brazil, being responsible for the growing damage caused by diseases. The objective of this work was to evaluate the effect of different maize production systems, contrasting in management investments, on the incidence of stalk rot, rot grains and grain yield. Four production systems were tested: S1 (low management level), S2 (medium), S3 (high) e S4 (designed to maximize the grain yield). The production systems dif (more) fered in relation to plant density, row spacing, amount of fertilizer and irrigation use. Three genotypes were used for each production system: BRS Planalto (open-pollinated variety), Traktor (double-cross hybrid) and P32R21 (single-cross hybrid). The experiments were carried out during 2002/03 and 2003/04 grown seasons, in no-till system and a monoculture area, having a mixture of black oat and vetch as the preceding winter crop. The experiments was a split-plot arranged in randomized complete blocks design with four replications. In both grown seasons, regardless management system, open-pollinated variety BRS Planalto showed higher stalk rot than the hybrids. Colletotrichum graminicola was the main pathogen associated with stalk rot. Grain yield ranged from 3,986 to 13.489kg ha-1 in 2003 and from 1,787 to 13.849kg ha-1 in 2004, depending on genotype and crop management system. The highest values of grain yield were obtained in S4 with the single-cross hybrid. The incidence of rot grain was low (below 6%) during the whole experimental period. Fusarium verticillioides was the main pathogen associated with rot grain. There was no association between incidence and causal agent of stalk rot and rot grain. It was not possible to identify a crop management system that was more efficient to reduce incidence of stalk rot and rot grain.

The effects of four bacterial biocontrol agents on Fusarium verticillioides infection and fumonisin accumulation in the maize agroecosystem were evaluated in a 2-year field study. The antagonistic abilities of the four agents were examined following two application techniques consisting of inoculating seeds during pre-sowing and maize ears at flowering. Seed inoculation with F. verticillioides and co-inoculation with this fungus and each of the four agents were also examined. Treatment effects on maize performance were also assessed through determination of the number of plants per hectare, kernels yield (kg ha-1) and kernel-cob relations. F. verticillioides infection and fumonisin B1 contents were determined in kernels of physiologically mature maize plants at harvest time. Maize yield re...

Abstract in portuguese O objetivo deste estudo foi avaliar a metodologia SREG GGE biplot e a análise de fatores na estratificação da interação genótipos×ambientes em milho. Foram avaliados 49 híbridos comerciais de milho de ciclo precoce em nove ambientes. Foi utilizado o delineamento látice quadrado 7×7, com duas repetições. Cada parcela consistiu de duas linhas de 5m espaçadas por 0,90m. Para a realização das análises, foram utilizados dados de produtividade de grão (more) s. Os resultados indicaram a existência de dois mega-ambientes no Estado de Minas Gerais para híbridos de milho de ciclo precoce. A estratificação de ambientes pela análise de fatores mostrou-se mais seletiva em reunir ambientes pela similaridade de desempenho dos cultivares, mas não evidenciou as interações genótipos x ambientes específicas, o que foi possível pela análise SREG GGE biplot. Abstract in english The objective of this study was to evaluate the use of SREG GGE biplot methodology and factor analysis to stratify the genotype×environment interaction in maize. Forty-nine early maize hybrids were evaluated in nine environments. The experimental design used was a 7×7 square lattice with two replicates. Each plot consisted of two 5m long rows spaced 0.90m apart. Grain yield data were used to perform the analysis. The results indicated the existence of two mega (more) -environments in the State of Minas Gerais, Brazil, for early maize hybrids. The stratification of the environment by factor analysis was more selective to join the similarity the according with cultivar performance. However, this approach did not identify specific genotype x environment interactions, which is possible through SREG GGE biplot analysis.

Abstract in portuguese Os objetivos do trabalho foram avaliar o manejo de adubação com N e S (como sulfato de amônio) nos componentes de produção do milho e no N e S acumulados pela cultura, assim como avaliar o valor mínimo de Índice de Suficiência em Nitrogênio (ISN=0,95), como um indicativo da necessidade da adubação em cobertura, em plantio direto. O delineamento experimental foi blocos casualizados com seis tratamentos e quatro repetições em Latossolo Vermelho distrófico (Hap (more) ludox), em Campo Mourão (PR), utilizando os tratamentos no milho: T1- N 120 kg ha-1 na semeadura; T2- 120 kg ha-1 de N em cobertura; T3- 40 kg ha-1 de N na semeadura 80 kg ha-1 de N em cobertura; T4- 30 kg ha-1 de N na semeadura e 90 kg ha-1 N em cobertura, cuja necessidade foi monitorada pelo clorofilômetro, em função do Índice de Suficiência em Clorofila (ISC); T5- 120 kg N ha-1 antecipado na semeadura do trigo; T6- controle, sem aplicação de N. A necessidade da adubação nitrogenada em cobertura, no tratamento monitorado, foi avaliada pelo Índice de Suficiência em Nitrogênio (ISN), sendo determinado pela relação entre a leitura média do Índice Relativo de Clorofila Foliar (IRC) nas folhas da parcela estudada e a média da leitura do IRC na parcela de referência, a qual recebeu dose total de N e S na semeadura do milho. No primeiro ano, com chuvas mais regulares, o milho produziu melhor nos tratamentos onde o fertilizante foi aplicado em dose completa na semeadura ou em cobertura. A aplicação da dose completa do sulfato de amônio, antecipado na semeadura do trigo, proporcionou produtividade do milho sem diferença da adubação parcelada. Já no segundo ano, com chuvas irregulares e menor eficiência do fertilizante, não houve diferença entre as formas de manejo do sulfato de amônio na produtividade do milho na semeadura do trigo. O ISN de 0,95 não foi eficiente para avaliar o N requerido pelo milho na época da cobertura e a omissão do fertilizante resultou em menor produtividade do milho. O N acumulou-se mais nos grãos, enquanto o S acumulou-se mais na palha; porém ambos foram altamente correlacionados à produtividade do milho. Abstract in english The objectives of this work were to evaluate the management of N and S (as ammonium sulphate) fertilization under no-tillage system on the components of maize productivity and on N and S accumulation in the crop, as well as to evaluate the minimum value of the Nitrogen Sufficiency Index (NSI 0.95) as an indicator for side dressing requirements. The experiment had a completely randomized block design with six treatments and four replications carried out in Red Latosol dyst (more) rophic soil (Hapludox), in Campo Mourão, Paraná State, where the following treatments in summer growth maize were applied: T1- 120 kg ha-1 N in seeding; T2- 120 kg ha-1 N in side dressing; T3- 40 kg ha-1 N in seeding and 80 kg ha-1 N in side dressing; T4- 30 kg ha-1 N in seeding and 90 kg ha-1 N in side dressing, monitored by a chlorophyll meter using the Nitrogen Sufficiency Index (NSI); T5- 120 kg ha-1 N anticipated in wheat seeding; T6- without nitrogen fertilization. NSI was determined by the relationship between the leaf chlorophyll index (ICF) average of T4 plants and that one in the plot fertilized with 120 kg ha-1 N at the maize seed sowing (T1). During two years, ammonium sulphate was applied to the maize crop after wheat under no tillage system. In the first year, with adequate rainfall, the maize yield was similar to the one in which the complete ammonium sulphate dose application was done in maize seeding and side dressing. The anticipated fertilization to wheat seed sowing resulted in maize yield without difference from the parceled form. In the second year, with irregular rainfall, all treatments with N were similar and they increased maize yield compared to that without N fertilization. NSI of 0.95 was not efficient to evaluate maize N requirements in side dressing, and resulted in lower maize yield. N was accumulated mainly in the grains unlike S that accumulated in the plant shoots; both were highly correlated to maize productivity.

while the relation for plants growing under limiting nitrogen conditions and L° _eater ...... of maize, sorghum, and rice. Agric. For. .... Ham, G. E., and Caldwell, A. C. (1978), Fertilizer placement effects on soybean seed yield, Nz fixation,. 33p ...

Abstract in portuguese A adequada combinação entre a escolha da densidade de plantas e do híbrido é um dos fatores que contribuem para o aumento da produtividade do milho. O objetivo deste trabalho foi avaliar o efeito do incremento na densidade de plantas sobre a incidência de podridões do colmo, de grãos ardidos e o rendimento de grãos de dois híbridos de milho contrastantes quanto a tolerância ao adensamento. O experimento foi conduzido em Lages, SC, nas safras agrícolas 2002/03 e (more) 2003/04, em área de semeadura direta e monocultura, sob sucessão de cobertura morta constituída de aveia preta+ervilhaca. Estudou-se a combinação de dois fatores: híbrido e densidades, utilizando-se o delineamento experimental de blocos casualizados com parcela sub-dividida. Na parcela principal avaliaram os híbridos: Speed (simples, tolerante ao adensamento) e AG 303 (duplo, intolerante ao adensamento). Nas sub-parcelas testaram-se cinco densidades de plantas: 25, 50, 75, 100 e 125 mil plantas ha-1. O aumento da densidade de plantas, proporcionou incremento linear na incidência das podridões do colmo e grãos ardidos para os dois híbridos e duas safras avaliadas. O fungo Colletotrichum graminicola foi o mais detectado em colmos doentes, seguido do Fusarium graminearum, F. verticillioides e Stenocarpella sp. Nos grãos ardidos, os fungos predominantes foram F. verticillioides, F. graminearum e Penicillium spp. O híbrido AG 303 demonstrou menor resposta no rendimento do que o híbrido Speed com o aumento da população de plantas. Não foi observada associação direta entre o maior rendimento de grãos do híbrido simples em estandes adensados e a menor incidência de doenças de colmo e de grãos ardidos. Abstract in english The combination between plant density and hybrid choice is an important factor to enhance maize grain yield. The objective of this work was to evaluate the increasing of plant density on the incidence of stalk rot, rot grains and grain yield of two maize hybrids with contrasting tolerance to crowding. The experiment was carried out in Lages-SC, during the crop seasons of 2002/03 and 2003/04, in an area of no-tillage and monoculture, having a mixture of black oat and vetch (more) as the preceding winter crop. The experimental design was a randomized block with split plot arrangement and three replications per treatment. Two hybrids were evaluated in the main plots: Speed (a single-cross hybrid tolerant to crowding) and AG 303 (a double-cross hybrid intolerant to crowding). Each hybrid was submitted to five plant densities in the split-plots: 25, 50, 75, 100 and 125 thousand plants per ha. The increase in plant density enhanced linearly the occurrence of stalk rot and rot grains for both hybrids and crop seasons. The fungus Colletotrichum graminicola was detected with great frequency in the stalk rot, regardless of hybrid and crop season, followed by Fusarium graminearum, F. verticillioides and Stenocarpella sp. The predominant fungi in rot grains were F. verticillioides, F. graminearum and Penicillium spp. The grain yield of AG 303 was less responsive to the increment in plant density. No association between the higher grain yield of the single-cross hybrid Speed at dense stands and the lower incidence of stalk rot and rot grains was detected.

Abstract in portuguese Os trigos mexicanos apresentam características agronômicas de interesse podendo ser recomendados para cultivo em condições de solo onde o alumínio não é um fator limitante ou serem utilizados como fontes genéticas em programas de melhoramento. O objetivo deste estudo foi avaliar o comportamento agronômico de 18 linhagens de trigo introduzidos do Centro Internacional de Melhoramento do Milho e Trigo, Cimmyt, México e duas cultivares-controle IAC-24 e IAC-289, em (more) um experimento instalado em Monte Alegre do Sul (SP), em condições de solo corrigido e irrigado por aspersão, no período de 1999-2002. Avaliaram-se os seguintes caracteres: produção de grãos, altura de plantas, acamamento, ciclo da emergência ao florescimento, comprimento da espiga, número de espiguetas por espiga, número de grãos por espiga e por espigueta e massa de cem grãos. L1 (SERI M 82) e L15 (DESCONHECIDO) destacaram-se para produção de grãos. L1 destacou-se pelo ciclo tardio, alto número de espiguetas por espiga e de grãos por espiga e baixa massa de cem grãos e L15, pela precocidade para florescer e elevada massa de cem grãos. L3 (FASAN) e L16 (KAUZ*2//TC*6/RL5406(RL6043)/3/KAUZ) destacaram-se pelo porte baixo; L6 (PRINIA) e L8 (CHIL/BUC), pelas espigas compridas; L3, pelo alto número de espiguetas por espiga; L9 (MUNIA/KAUZ) pelo grande número de grãos por espiga e por espigueta, e L18 (CETTIA), pelos grãos mais pesados. Em pelo menos dois anos, houve tendência de se obter maior produção de grãos em plantas semi-anãs mais altas com ciclo mais curto. Plantas produtivas apresentaram grãos pesados, espigas compridas com maior número de espiguetas e de grãos. Abstract in english The Mexican wheats present agronomic characteristics of interest being recommended for cultivation in soil conditions where aluminum is not a limiting factor or being utilized as genetic sources in breeding programs. The objective of this investigation was to evaluate 18 wheat inbred lines introduced from International Improvement Maize and Wheat Center, Cimmyt, Mexico, and the check cultivars IAC-24 and IAC-289 in trials carried out at Monte Alegre do Sul, SP, Brazil, in (more) limed soil under sprinkler irrigation conditions, during 1999-2002. Grain yield, number of days from emergence to flowering, plant height, lodging, spike length, number of spikelets per spike, number of grains per spike and per spikelet as well as weight of 100 grains were estimated. L1 (SERI M 82) e L15 (UNKNOWN) presented high grain yield. L1 was late and showed high spikelet and grain number per spike and low 100 grain weight and L15 was early to flower and exhibited high 100 grain weight. L3 (FASAN) and L16 (KAUZ*2//TC*6/RL5406(RL6043)/3/KAUZ) had low semidwarf plants; L6 (PRINIA) and L8 (CHIL/BUC) showed long spikes; L3, the largest number spikelet per spike; L9 (MUNIA/KAUZ), the largest number of grain per spike and per spikelet, and L18 (CETTIA), the heaviest grains. During two years, higher grain yield were obtained in higher semidwarf plants of shorter cycle. Higher grain yield plants presented heavier grains, longer heads with higher number of spikelets and grains.

DAS-59122-7 (59122) is a transgenic maize (Zea mays L.) that contains genes encoding Cry34Ab1 and Cry35Ab1 proteins from Bacillus thuringiensis Berliner strain 149B1 and phosphinothricin acetyltransferase (PAT) protein from Streptomyces viridochromogenes. Expression of these proteins in planta confers resistance to corn rootworms and other Coleopteran parasites and tolerance to herbicides containing glufosinate ammonium, respectively. In the current study, processed flours from 59122 maize grain or its near isogenic control line (091) were used at two concentrations (50% and 70% wt/wt) to produce diets that were fed to rats for 90 days in accordance with Chinese toxicology guidelines (GB15193.13-2003). A commercial AIN93G diet was used as an additional negative control. No significant differences in body weight and feed utilization were observed between rats consuming diets formulated with 59122 and 091 Control corn. Statistical differences (p<0.05) were observed in certain hematology and serum chemistry response variables between rats consuming diets formulated with 59122 or 091 Control flour compared to AIN93G diet. However, the mean value of these response variables in the 59122 groups were not statistically different from those observed in diets formulated with corresponding high and low concentrations of the flour from the 091 Control maize grain. Therefore, the statistical differences were considered to be related to consumption of diets containing high concentrations of maize flour (compared to AIN93G diets) regardless of source rather than to consumption of flour from 59122 maize grain. The results from this study demonstrated that 59122 maize grain is as safe as non-transgenic maize grain. PMID:18381227

Abstract in spanish En México la escasa rotación de cultivos ha afectado la capacidad del suelo para producir, el uso de genotipos de maíz con mayor potencial de rendimiento y sistemas de producción más intensivos ha incrementado la demanda de insumos; lo cual afecta la economía del productor. Para determinar el efecto de los cambios en el precio de los insumos y de los principales factores que explican la oferta de maíz grano en Guanajuato, en este trabajo se estimó un modelo econom (more) étrico compuesto por dos ecuaciones de oferta, tres de transmisión de los precios y una identidad para el periodo de 1980 a 2009. Los resultados indican que la oferta de maíz grano en el estado responde inelásticamente ante cambios en el precio medio rural del maíz producido bajo riego y de manera elástica si los cambios se suscitan en el mismo nivel de precio pero de la oferta en temporal, con elasticidades precio-propias de 0.8531 y 1.0604; los cambios en el precio de los insumos que más afectan la oferta estatal son el precio del plaguicida y de la mano de obra, con elasticidades precio-cruzada de -0.6154 y -0.5470; los cambios en el bien competitivo que más le impactan son los registrados en el frijol, con elasticidades precio-cruzada de -0.5489 si es producido bajo riego y de -1.0292 si es producido en temporal. El efecto de transmisión de los precios, indica que el precio al productor de maíz en riego y temporal estatal es influenciado directamente por el precio al mayoreo a razón de 0.79 y 0.80% por cada 1% de cambio en este último, mientras que el costo de transporte y el precio internacional del maíz inciden sobre el precio al mayoreo en el estado a niveles de 0.21 y 0.13% por cada cambio porcentual unitario en éstos. Abstract in english In Mexico, poor crop rotation has affected the capacity of soil to produce; the use of maize genotypes with higher yield potential and more intensive production systems has increased the demand for inputs, which affects the economy of the producer. To determine the effect of changes in input prices and the main factors that explain the supply of maize grain in Guanajuato, in the present work an econometric model was estimated; comprised of two supply equations, three tran (more) smission prices and an identity for the period from 1980 to 2009. The results indicate that the supply of maize grain in the state responds inelastically to changes in the producer price of maize produced under irrigation and elastically if changes arise in the same price level but the offer temporary, with elasticities own-price 0.8531 and 1.0604, changes in input prices that more affect the state offer are the pesticide and labor price, with cross-price elasticities of -0.6154 and -0.5470, changes in the competitive product that more impact are those in the bean, with cross-price elasticities of -0.5489, if produced under irrigation and -1.0292 if produced in temporary. The effect of price transmission, indicate that the producer price of maize under irrigation and temporary state is directly influenced by the wholesale price at a rate of 0.79 and 0.80% for each 1% change in it, while the cost of transport and the international price of maize influence on the wholesale price in the state at levels of 0.21 and 0.13% for every unit percentage change in them.

Abstract in spanish Una enfermedad del maíz de etiología desconocida apareció epidémicamente en el estado de Veracruz, México durante 2003-2004. Las plantas enfermas se caracterizaron por muerte prematura de plantas, producción múltiple de jilotes estériles, pudrición vascular, hojas con manchas blancas, amarillamiento, enrojecimiento y franjeado foliar y necrosis. El fitoplasma Maize bushy stunt (MBS) se detectó por PCR asociado a plantas con amarillamiento, enrojecimiento foliar (more) y proliferación de jilotes en los municipios de Tlalixcoyan, Cosoleacaque y Paso de Ovejas en 2006 y 2007. La incidencia, severidad y rendimiento se evaluaron en diez genotipos de maíz en una plantación experimental en Tlalixcoyan, Ver. en 2007. MBS se detectó por PCR en CP-562, 30F83, 30F92, Orca, 30F96, Nutria y Asgrow 7573, mientras que Pioneer 3086, 30F97 y CP-560 resultaron negativos. La mayor incidencia se presentó en los genotipos 30F83 (27%), AS7573 (21%) y 30F97 (21%) con una severidad de 0.29, 0.14 y 0.15, respectivamente. Los genotipos con mayor rendimiento de grano fueron AS-7573 (5.4 ton ha-1), Orca (4.7 ton ha-1) y 30F97 (4.0 ton ha-1). Hubo correlación positiva de la incidencia con la severidad de la enfermedad (r=0.69**), pero no de la enfermedad con el rendimiento. Abstract in english A maize disease of unknown etiology appeared in the state of Veracruz, Mexico, during 2003-2004. Diseased plants were characterized by premature death, proliferation and poor ear growth, sterility in both male and female flowers, stalk rot, leaves with white spots, yellowing and reddening on leaf margins, leaf stripes, and necrosis. Maize Bushy Stunt (MBS) phytoplasma was PCR detected and associated with plants with yellow and red leaves and ear proliferation in Tlalixcoy (more) an, Cosoleacaque and Paso de Ovejas counties in 2006 and 2007. Ten maize genotypes were evaluated for incidence and severity of the disease and grain yield performance in an experimental plot in Tlalixcoyan, Ver. in 2007. MBS was PCR detected in CP-562, 30F83, 30F92, Orca, 30F96, Nutria and Asgrow 7573; whereas Pioneer 3086, 30F97 y CP-560 were MBS negative. Highest incidence and severity was detected in 30F83 (27 %, 0.29), AS-7573 (21 %, 0.14) and 30F97 (21 %, 0.15). Best grain yield was produced by AS-7573 (5.4 ton ha-1), Orca (4.7 ton ha-1), and 30F97 (4 ton ha-1). Positive correlation was obtained between incidence and severity of the disease (r=0.69**), incidence and number of symptomatic ears (r=0.43**) and severity with decrease in weight of healthy grain (r=0.51**). There was no correlation between disease and yield.

More than 10 years after registration of the first Bt maize cultivar in Europe, there still exists a remarkable lack of data on effects on Lepidoptera which would be necessary for a complete and comprehensive environmental risk assessment. So far only very few European butterfly species have been tested in this aspect. In our study the effect of transgenic Bacillus thuringiensis (Bt) maize pollen (event Bt-176) on the development and survival of neonate larvae of the Peacock butterfly, Inachis io (L.) was for the first time shown. The results of our study suggest that the Peacock butterfly may serve as a model organism for assessing potential side effects of new developed transgenic Bt crops on non-target butterflies in a GMO environmental risk assessment. The study was done under laboratory conditions by exposing larvae of the Peacock butterfly to various pollen doses of transgenic maize event Bt-176 (cv. PACTOL CB) or the conventional isogenic maize (cv. PACTOL) using a no-choice test. Larvae feeding for 48 h on nettle plants (Urtica dioica) that were contaminated with higher pollen concentrations from Bt-176 maize (205 and 388 applied pollen.cm?²) suffered a significantly higher mortality rate (68 and 85% respectively) compared to larvae feeding on leaves with no pollen (11%), or feeding on leaves with pollen from conventional maize (6 to 25%). At lower Bt maize pollen doses (23-104 applied pollen.cm?²),mortality ranged from 11-25% and there were no apparent differences among treatments. The corresponding LC??-and LC??-values for neonate larvae of the Peacock butterfly were 187 and 448 applied pollen grains.cm?² of Bt-176, respectively.Weight of larvae surviving consumption of Bt-176 maize pollen declined between 10 and 81% with increased pollen doses (r = -0.95). The highest weight reduction (81%) corresponded to the highest pollen concentration (388 pollen grains applied.cm?²). Ingestion of pollen from the conventional maize hybrid did not have negative effects on larval weight gain or survival rate. PMID:21122482

Head smut, one of the most devastating diseases in maize, causes severe yield losses worldwide. Resistance to head smut has been proven to be a quantitative inherited trait. In our previous study, a major resistance quantitative trait locus (named qHSR1) was detected on maize chromosome 2 (bin 2.09), and a number of molecular markers have been developed in the qHSR1 region. Here, we report the marker-assisted introgression of qHSR1 to improve maize resistance to head smut. The 10 maize inbred lines, namely Ji853, 444, 98107, 99094, Chang7-2, V022, V4, 982, 8903, and 8902, which have high yield potential but are susceptible to head smut, were selected for resistance improvement. Each of the 10 high-yielding lines was crossed with a donor parent Ji1037 that is completely resistant to head sm...

Abstract in portuguese A utilização de águas salinas bem como o reúso de águas de drenagem na irrigação dependem de estratégias de longo prazo que garantam a sustentabilidade socioeconômica e ambiental dos sistemas agrícolas. Neste trabalho, avaliaram-se os efeitos da irrigação com água salina na estação seca e com água de baixa salinidade na estação chuvosa sobre o acúmulo de sais no solo e a produtividade de milho e feijão-de-corda em sistema de rotação. O experimento fo (more) i conduzido em campo, utilizando-se do delineamento em blocos ao acaso, com cinco repetições. O primeiro cultivo foi instalado durante a estação seca de 2007, com a cultura do milho irrigada com água de diferentes salinidades (0,8; 2,2; 3,6 e 5,0 dS m-1). As plantas foram coletadas aos 90 dias após a semeadura (DAS), sendo realizadas as avaliações: crescimento vegetativo, produção de grãos por planta, matéria seca de 1.000 grãos e produtividade. Durante a estação chuvosa de 2008, foi cultivado o feijão caupi nas mesmas parcelas que foram cultivadas com milho. Ao final do ciclo, as plantas foram coletadas, sendo realizadas avaliações de crescimento vegetativo e produtividade. Amostras de solo foram coletadas antes e após o cultivo do milho e ao final do cultivo com feijão caupi. A salinidade da água de irrigação acima 2,2 dS m-1 reduziu a produtividade do milho durante o período seco. Os elevados totais de precipitação pluviométrica durante a estação chuvosa proporcionaram a lixiviação dos sais acumulados durante o cultivo na estação seca e eliminaram os possíveis efeitos negativos da salinidade sobre o feijão caupi. Porém, o feijão caupi apresentou um comportamento atípico com uma expressiva proporção de massa vegetativa e baixa produção de vagens, o que reduziu a eficiência dessa estratégia de rotação de culturas, nas condições do presente estudo. Abstract in english The use of saline water and the reuse of drainage water for irrigation depend on long-term strategies that ensure the sustainability of socio-economic and environmental impacts of agricultural systems. In this study, it was evaluated the effects of irrigation with saline water in the dry season and fresh water in the rainy season on the soil salt accumulation yield of maize and cowpea, in a crop rotation system. The experiment was conducted in the field, using a randomize (more) d complete block design, with five replications. The first crop was installed during the dry season of 2007, with maize irrigated with water of different salinities (0.8, 2.2, 3.6 and 5.0 dS m-1). The maize plants were harvested at 90 days after sowing (DAS), and vegetative growth, dry mass of 1000 seeds and grain yield were evaluated. The same plots were utilized for the cultivation of cowpea, during the rainy season of 2008. At the end of the crop, cycle plants of this species were harvested, being evaluated the vegetative growth and plant yield. Soil samples were collected before and after maize and cowpea cultivation. The salinity of irrigation water above 2.2 dS m-1 reduced the yield of maize during the dry season. The high total rainfall during the rainy season resulted in leaching of salts accumulated during cultivation in the dry season, and eliminated the possible negative effects of salinity on cowpea plants. However, this crop showed atypical behavior with a significant proportion of vegetative mass and low pod production, which reduced the efficiency of this strategy of crop rotation under the conditions of this study.

A multi-year field experiment was conducted to study the variation features of rhizosphere environment and crop root growth under the cropping modes of wheat-soybean (A1), wheat-sweet potato (A2), maize (A3), wheat/maize/soybean (A4), and wheat/maize/sweet potato (A). Among the five modes, A4 increased the plant biomass, root activity, and root dry mass of wheat, maize, and soybean at their flowering and maturing stages, and the quantity of rhizosphere soil bacteria, fungi, and actinomycetes. The biomass and quantity of rhizosphere soil microbes were relay strip intercropping > single cropping, soybean > sweet potato, and fringe row > center row. It was suggested that wheat/maize/soybean relay trip intercropping could improve rhizosphere environment, promote the crops root growth and increase their aboveground biomass, and accordingly, realize yield-increasing. PMID:22489489

Abstract in portuguese Os resíduos vegetais das culturas, ao se decomporem, alteram os atributos químicos do solo e, como consequência, influenciam a produtividade das culturas em sucessão. O objetivo deste trabalho foi avaliar os atributos químicos do solo e a produtividade das culturas de soja, milho e arroz, cultivadas no verão, em sucessão a culturas de inverno em semeadura direta. O experimento foi realizado em Jaboticabal-SP (48 ° 18 ' 58 '' W e 21 ° 15 ' 22 '' S), em um Latossol (more) o Vermelho eutrófico. O delineamento experimental foi em blocos ao acaso, no esquema em faixas, com três repetições. Os tratamentos foram constituídos pela combinação de quatro sequências de culturas de verão (monoculturas de milho e soja e rotações soja/milho e arroz/feijão/algodão) com sete culturas de inverno (milho, girassol, nabo forrageiro, milheto, guandu, sorgo e crotalária). Os cultivos iniciaram-se em 2002. Após o manejo das culturas de inverno e antes da semeadura das culturas de verão do ano agrícola 2006/2007, foram coletadas amostras de solo nas camadas de 0-2,5; 2,5-5,0; 5-10; 10-20; e 20-30 cm. Nas amostras de solo, foram determinados: teores de matéria orgânica, pH, teores de P (resina), K, Ca e Mg trocáveis e acidez potencial (H + Al). As sequências de verão rotação soja/milho e milho em monocultura proporcionaram no solo menores teores de matéria orgânica na camada de 0-10 cm e de P do solo na camada de 0-20 cm. Na sequência de verão arroz/feijão/algodão, maiores teores de K foram proporcionados pelas culturas de inverno crotalária e nabo forrageiro, na camada de 0-10 cm, e milheto, na de 0-2,5 cm. Crotalária, milheto, nabo forrageiro e sorgo, cultivados no inverno, proporcionaram maiores teores de matéria orgânica no solo na camada de 0-30 cm. Maiores teores de P no solo foram proporcionados pela crotalária, na camada de 0-2,5 cm, e pelo nabo forrageiro, na de 0-5 cm. Maiores produtividades de soja, como monocultura de verão, foram obtidas após nabo forrageiro e crotalária e, quando em rotação com milho no verão, após nabo forrageiro, crotalária e milheto. Maiores produtividades de milho foram obtidas após nabo forrageiro, milheto e guandu, e menor produtividade de arroz foi obtida após sorgo. Abstract in english Decomposing crop residues in no-tillage system can alter soil chemical properties, which may consequently influence the productivity of succession crops. The objective of this study was to evaluate soil chemical properties and soybean, maize and rice yield, grown in the summer, after winter crops in a no-tillage system. The experiment was carried out in Jaboticabal, SP, Brazil (21 ° 15 ' 22 '' S; 48 ° 18 ' 58 '' W) on a Red Latosol (Oxisol), in a completely randomized b (more) lock design, in strip plots with three replications. The treatments consisted of four summer crop sequences (maize monocrop, soybean monocrop, soybean/maize rotation and rice/bean/cotton rotation) combined with seven winter crops (maize, sunflower, oilseed radish, pearl millet, pigeon pea, grain sorghum and sunn hemp). The experiment began in September 2002. After the winter crops in the 2005/2006 growing season and before the sowing of summer crops in the 2006/2007 season, soil samples were collected in the layers 0-2.5; 2.5-5.0; 5-10; 10-20; and 20-30 cm. Organic matter, pH, P, K+, Ca2+, Mg2+, and H + Al were determined in each soil sample. In the summer soybean/maize rotation and in maize the organic matter contents and P levels were lower, in the layers 0-10 cm and 0-20 cm, respectively. Summer rice/bean/cotton rotation increased soil K levels at 0-10 cm depth when sunn hemp and oilseed radish had previously been grown in the winter, and in the 0-2.5 cm layer for millet. Sunn hemp, millet, oilseed radish and sorghum grown in the winter increased organic matter contents in the soil down to 30 cm. Higher P levels were found at the depths 0-2.5 cm and 0-5 cm, respectively, when sunn hemp and oilseed radish were grown in the winter. Highest grain yields for soybean in monoculture were obtained in succession to winter oilseed radish and sunn hemp and in rotation with maize, after oilseed radish, sunn hemp and millet. Maize yields were highest in succession to winter oilseed radish, millet and pigeon pea. Rice yields were lowest when grown after sorghum.

Maize is the New World's preeminent grain crop and it provided the economic basis for human culture in many regions within the Americas. To flourish, maize needs water, sunlight (heat), and nutrients (e. g., nitrogen). In this paper, climate and soil chemistry data are used to evaluate the potential for dryland (rainon-field) agriculture in the semiarid southeastern Colorado Plateau and Rio Grande regions. Processes that impact maize agriculture such as nitrogen mineralization, infiltration of precipitation, bare soil evaporation, and transpiration are discussed and evaluated. Most of the study area, excepting high-elevation regions, receives sufficient solar radiation to grow maize. The salinities of subsurface soils in the central San Juan Basin are very high and their nitrogen concentrations are very low. In addition, soils of the central San Juan Basin are characterized by pH values that exceed 8.0, which limit the availability of both nitrogen and phosphorous. In general, the San Juan Basin, including Chaco Canyon, is the least promising part of the study area in terms of dryland farming. Calculations of field life, using values of organic nitrogen for the upper 50 cm of soil in the study area, indicate that most of the study area could not support a 10-bushel/acre crop of maize. The concepts, methods, and calculations used to quantify maize productivity in this study are applicable to maize cultivation in other environmental settings across the Americas. ?? 2010 US Government.

Maize is the New World?s preeminent grain crop and it provided the economic basis for human culture in many regions within the Americas. To flourish, maize needs water, sunlight (heat), and nutrients (e.g., nitrogen). In this paper, climate and soil chemistry data are used to evaluate the potential for dryland (rain-on-field) agriculture in the semiarid southeastern Colorado Plateau and Rio Grande regions. Processes that impact maize agriculture such as nitrogen mineralization, infiltration of precipitation, bare soil evaporation, and transpiration are discussed and evaluated. Most of the study area, excepting high-elevation regions, receives sufficient solar radiation to grow maize. The salinities of subsurface soils in the central San Juan Basin are very high and their nitrogen concentra...

The flavone luteolin was extracted, isolated and purified from leaves of Cichorium endivia L. subsp. divaricatum and identified based on 1H and 13C NMR spectral analyses. Luteolin (0.0015 %) was applied to two cultivars of maize (Giza 2 and single cross 10) grains, germinated in the absence and presence of NaCl, in order to assess the bioactivity of luteolin and its role in alleviating the harmful effect of salt stress on maize. The results showed that luteolin enhanced germination and seedling growth of both maize cultivars in normal conditions. Furthermore, luteolin successfully alleviated the harmful effect of salinity on germination and seedling growth of maize. The potential role of luteolin was performed mainly by stimulating ?-amylase activity leading to enhancing starch mobilizatio...

Extreme weather conditions can strongly affect agricultural production, with negative impacts that can at times be detected at regional scales. In France, crop yields were greatly influenced by drought and heat stress in 2003 and by extremely wet conditions in 2007. Reported regional maize and wheat yields where historically low in 2003; in 2007 wheat yields were lower and maize yields higher than long-term averages. An analysis with a spatial version (10???10?km) of the EPIC crop model was tested with regards to regional crop yield anomalies of wheat and maize resulting from extreme weather events in France in 2003 and 2007, by comparing simulated results against reported regional crops statistics, as well as using remotely sensed soil moisture data. Causal relations between soil moisture...

Abstract in portuguese Este trabalho objetivou avaliar a divergência genética em genótipos de milho no sul do estado do Tocantins. O experimento foi realizado no município de Gurupi - TO. As populações foram obtidas de 70 híbridos top cross pelo cruzamento de linhagens S6 com um testador, utilizando-se 11 cultivares como testemunha, totalizando 81 genótipos. O delineamento experimental utilizado foi blocos casualizados com duas repetições. As características avaliadas foram: altura d (more) a planta, altura da espiga, prolificidade, comprimento de espiga, diâmetro de espiga, peso de 100 grãos, peso hectolítrico e produtividade de grãos. A divergência genética foi avaliada por procedimentos multivariados como a distância generalizada de Mahalanobis e pelos métodos de agrupamento de otimização de Tocher e vizinho mais próximo. Encontrou-se divergência genética entre as populações estudadas promovendo a formação de grupos diferentes entre o método de Tocher e do vizinho mais próximo. As características produtividade e comprimento de espiga foram as que mais e menos, respectivamente, contribuíram na diversidade genética dos genótipos. Abstract in english This study aimed to evaluate the genetic diversity in maize genotypes in the southern of Tocantins. The experiment was conducted at Gurupi - TO, Brazil. The populations were obtained from 70 top cross, with crossing the lineages S6 with a tester, and using 11 cultivars as a witness, totaling 81 genotypes. The experimental design was randomized blocks with two replications. The characteristics assessed were: plant height, ear height, prolificacy, ear length, ear diameter, (more) weight of 100 grains, hectoliter weight and grain yield. Genetic divergence was assessed by multivariate procedures: Mahalanobis distance, clustering methods of Tocher and nearest neighbor. It was found genetic divergence among populations and the formation of non congruent groups between the method of Tocher and nearest neighbor. The yield grain was the major contributor to the genetic diversity and the ear length was the least.

Fusarium graminearum Schwabe (teleomorph Gibberella zeae) is a plant pathogen causing scab disease on wheat and barley that reduces crop yield and grain quality. F. graminearum also causes stalk and ear rots of maize and is a producer of mycotoxins such as the trichothecenes that contaminate grain and are harmful to humans and livestock (Goswami and Kistler, 2004). The fungus produces two types of spores. Ascospores, the propagules resulting from sexual reproduction, are the main source of primary infection. These spores are forcibly discharged from mature perithecia and dispersed by wind (Francl et al 1999). Secondary infections are mainly caused by macroconidia which are produced by asexual means on the plant surface. To study the developmental processes of ascospores in this fungus, a procedure for their collection in large quantity under sterile conditions was required. Our protocol was filmed in order to generate the highest level of information for understanding and reproducibility; crucial aspects when full genome gene expression profiles are generated and interpreted. In particular, the variability of ascospore germination and biological activity are dependent on the prior manipulation of the material. The use of video for documenting every step in ascospore production is proposed in order to increase standardization, complying with the increasingly stringent requirements for microarray analysis. The procedure requires only standard laboratory equipment. Steps are shown to prevent contamination and favor time synchronization of ascospores. PMID:8210178

Soil water conservation through tillage is widely accepted as one of the ways of improving crop yields in rainfed agriculture. Field experiments were conducted between 2007 and 2009 to evaluate the effects of conservation tillage on the yields and crop water use efficiency of maize (Zea mays L.) and cowpea (Vigna unguiculata L.) in eastern Kenya. Experimental treatments were a combination of three tillage practices and four cropping systems. Tillage practices were tied-ridges, subsoiling-ripping and ox-ploughing. The cropping systems were single crop maize, single crop cowpea, intercropped maize-cowpea and single crop maize with manure. The treatments were arranged in split plots with tillage practices as the main plots and cropping systems as the sub-plots in a Randomized Complete Block D...

Abstract in portuguese O desenvolvimento de variedades de milho (Zea mays L.) com maiores teores de proteína e óleo nos grãos e um balanço adequado de aminoácidos, sem prejuízo do rendimento de grãos, representa um desafio para o melhoramento. Estudou-se a qualidade nutricional em dez populações brasileiras de milho. As populações foram avaliadas em três ambientes. Os experimentos foram realizados em delineamento de blocos casualizados com seis repetições. Foram avaliados o rendim (more) ento de espigas e as concentrações de proteína, óleo, serina, ácido glutâmico, alanina, leucina, tirosina e fenilalanina. Análises de variância por experimento e conjunta foram realizadas. Há variação entre populações para a maioria dos caracteres estudados. Há efeito de ambiente para a maioria dos caracteres, mas não da interação genótipo-ambiente, permitindo a seleção para a média dos ambientes. Existe uma associação positiva entre o teor de proteína e o da maioria dos aminoácidos quando considerados com base na matéria seca e não há associação entre a qualidade nutricional e o rendimento. Portanto, é possível o desenvolvimento de cultivares superiores para ambos os caracteres. Abstract in english Development of maize (Zea mays L.) cultivars with high grain protein and oil concentrations and an appropriate amino acid composition, without losses in grain yield, represents a challenge in breeding programs. The objective of this work was to study the nutritional quality of ten Brazilian maize populations evaluated in three environments. A randomized block design with six replications was used. Ear yield and the concentrations of protein, oil, serine, glutamic acid, al (more) anine, leucine, tyrosine and phenylalanine were evaluated. Individual and combined analyses of variance were performed. Populations diverged for most of the traits. Environmental effects influenced variation for most of the traits, unlike genotype-environment interaction, allowing the selection on the average of environments. Positive association exists among protein and most of the amino acids, when considered on a dry matter basis and there is no association between nutritional quality and yield; therefore, the development of cultivars that are superior for both traits is expected to be feasible.

In this study, we compared the effects of three pruning frequencies (3, 4 and 6cutsyr^-^1) of Gliricidia sepium hedgerows on (i) the productivities of shoot residues and maize grain, and (ii) on chemical and physical properties of a kaolinitic soil. Productivities of gliricidia shoots (GSP) and maize grain (MGP) were evaluated from 2001 to 2003. In 2004, soil samples were taken from the experimental plots at 0-5cm and 5-20cm depths and analyzed for total and particulate organic C (TOC and POM-C), percent of water stable aggregates (WSA), aggregate mean weighed diameter and cation exchange capacity (CEC). An adjacent native forest and a sole maize field under conventional till were also sampled as reference areas. Increasing pruning frequency resulted in a reduction of GSP from 6 and 4tha^-...

Most of the maize kernel oil is located in the embryo while the majority of starch is located in the endosperm. Maize kernel composition and value are affected significantly by the ratio of the embryo size to the endosperm size; however, the genetic regulation of embryo to endosperm ratio (EER) in maize is unknown. Here we identified ZmGE2 gene, which encodes a cytochrome p450 protein, as a gene associated with EER variation in maize. We first expressed rice Giant Embryo (GE) gene driven by oleosin promoter in maize and detected a 23.2 % reduction in EER in transgenic seeds, demonstrating the existence of evolutionarily conserved mechanisms for EER determination in rice and maize. We next identified maize GE2, a homolog of rice GE sharing 70 % identity in amino sequence, as a candidate based on the similar expression pattern and co-localization with a previously detected QTL for EER. Followed by linkage and association mapping, a 247-bp transposable element (TE) insertion in 3'-untranslated region of ZmGE2 gene was identified to be associated with increase in EER and kernel oil content. Expression level of the favorable ZmGE2 allele containing the 247-bp TE insertion was strongly reduced. In addition, the 247-bp TE insertion site was a selection target during the artificial long-term selection for the high EER trait in a high oil population. This is the first report that demonstrates an association of ZmGE2 with EER variation in maize and identifies ZmGE2 gene as a promising target for manipulation of EER and grain composition by either transgenic approach or molecular breeding in maize. PMID:22772589

Abstract in portuguese Novos híbridos de milho são normalmente desenvolvidos utilizando-se altas doses de N durante o ciclo de seleção. Isto pode favorecer o lançamento de genótipos que apresentem consumo de luxo de N ou requeiram altas doses deste nutriente para expressarem o seu potencial produtivo. Este trabalho foi conduzido para avaliar os efeitos de doses de N sobre o rendimento de grãos e eficiência de uso do N de híbridos cultivados em diferentes épocas no sul do Brasil. O ens (more) aio foi conduzido em Lages, Santa Catarina. Os híbridos Ag 12, Ag 28, Ag 303 e Ag 9012, lançados comercialmente nas décadas de 60, 70, 80 e 90, respectivamente, foram avaliados na parcela principal. Doses de N de 0, 50, 100 e 200 kg ha-1 foram aplicadas em cobertura nas subparcelas. O híbrido moderno Ag 9012 expressou maior rendimento de grãos do que os demais híbridos, independentemente da dose de N testada. Quando foram utilizadas altas doses de N, os híbridos antigos Ag 12 e Ag 28 absorveram mais N e concentraram mais matéria seca na parte aérea durante o florescimento. No entanto, produziram menor número de grãos por espiga, menor rendimento de grãos e eficiência de uso do nitrogênio. Abstract in english Genetic selection of maize hybrids is often conducted using high N rates during the breeding cycle. This procedure may either lead to the release of genotypes that present nitrogen luxury consumption or require a stronger N input to accomplish their yield potential. This work was carried out to evaluate the effects of N rates on grain yield and N use efficiency of hybrids cultivated in different decades in Southern Brazil. The trial was performed in Lages, Santa Catarina (more) State. A split plot design was used. Hybrids Ag 12, Ag 28, Ag 303 and Ag 9012, released during the 60's, 70's, 80's and 90's, respectively, were evaluated in the main plots. Nitrogen rates equivalent to 0, 50, 100 and 200 kg ha-1 were side-dressed in the split-plots when each hybrid had six fully expanded leaves. Modern-day hybrid Ag 9012 had higher grain yield than hybrids of earlier eras, regardless of N rates. Under high doses of N, the older hybrids Ag 12 and Ag 28 took up more N and presented higher values of shoot dry matter at flowering than Ag 9012. Nonetheless, they set less grains per ear which contributed to decrease their grain yield and N use efficiency.

Abstract in spanish El maíz producido para la industria de la masa y la tortilla o de la industria de harinas nixtamalizadas (IHN), debe satisfacer los requerimientos de eficiencia en el procesamiento y la calidad del producto final. El objetivo del presente trabajo fue determinar la calidad de maíces comerciales y precomerciales, para la elaboración de harinas nixtamalizadas, masa y tortilla, producidos en entidades ubicadas en el trópico húmedo y sub-húmedo de México en 2006. Se tra (more) bajó con 14 muestras de maíz cultivadas en el ciclo primavera-verano 2006 en el estado de Chiapas, Guerrero, Tamaulipas y Veracruz. La calidad se evalúo en términos de características físicas de grano y variables de nixtamalización; en tortilla se determinó textura y color. Todas las muestras fueron de grano blanco, característica común en los maíces tropicales, y por tanto adecuadas para la industria de harinas nixtamalizadas. Los maíces de Veracruz presentaron una calidad sobresalientes para este tipo de industria, por sus elevados rendimientos en masa y tortilla y excelente calidad. De todas las muestras analizadas, únicamente los maíces V-454-C10 (Tamaulipas) y H-561 (Chiapas) fueron adecuados para la industria de harinas nixtamalizdas. Las industrias relacionadas con el procesamiento alcalino del grano de maíz requieren contar con una materia prima especializada que permita mejorar su competitividad y ofrecer al consumidor el mejor producto posible, por tanto quienes hacen el mejoramiento genético de este cereal, deben tener en cuenta los parámetros agronómicos y de calidad. Abstract in english The corn produced for the masa or dough and tortilla industry or for nixtamalized flours industry (IHN), it should satisfy the requirements of efficiency in process and quality of final product. The aim of this work was to determine the quality of commercial and pre-commercial corns, for elaboration of nixtamalized flours, dough and tortilla, produced in states located in the humid and sub-humid tropic of Mexico in 2006. This study used 14 corn samples cultivated in sprin (more) g-summer 2006 cycle in States of Chiapas, Guerrero, Tamaulipas and Veracruz. The quality was evaluated in terms of physical characteristics of grain and nixtamalization variables; in tortilla it was determined texture and color. All samples were of white grain, common characteristic in tropical maizes, and therefore appropriate for nixtamalized flours industry. The maizes of Veracruz showed outstanding quality for this industry type, by their high dough and tortilla yields and excellent quality. From all analyzed samples, only maizes V-454-C10 (Tamaulipas) and H-561 (Chiapas) were proper for nixtamalized flours industry. The industries related with the alkaline processing of grain of maize require to have a specialized raw material that allows to improve their competitiveness and to offer to consumer the best possible product, therefore who make the genetic improvement of this cereal they should keep in mind the agronomic and quality parameters.

The methane yields and conversion of pentoses (xylose) and hexoses (cellulose) in hemp, maize, and white lupin were studied over 30 days of anaerobic digestion. Preservation of hemp increased the methane yield by 23% compared with the fresh hemp. The increased methane yield of hemp was verified by the enhanced conversion of C6 sugars, increasing from 48% to about 70%, whereas the conversion of C5 sugars increased from only 9% to nearly 50%. The consumption of all carbohydrates in fresh maize was almost complete in the 30 days of anaerobic digestion. Hence, there was no major difference in carbohydrate consumption between fresh and preserved maize during biogas production. Fresh white lupin produced the highest methane yield (343 ± 33 dm(3) kg(-1) TS) in this work, mainly due to its highest amount of proteins. Conversion of C6 sugars was 80%, but that of C5 sugars was notably less at 46%. PMID:22788699

Sitophilus zeamais Motschulsky, the maize weevil, Oryzaephilus surinamensis L, the saw-toothed grain beetle, and Tribolium castaneum Herbst, the red flour beetle, were exposed for 1, 2, 3, and 6 days at 22, 27, and 32°C on corn treated with 0, 0.5, 1.0, 2.0, or 4 ppm thiamethoxam, a new- generation ...

Maize and grain sorghum were grown for 39 d in sunlit environment-controlled chambers at 360 (ambient) and 720 (double-ambient, high) µmol mol-1 [CO2]. The most enhancement by high [CO2] on canopy photosynthesis (Pg), measured at 1,200 µmol m-2 s-1 solar PPFD, occurred at early plant growth stage, 1...

The potential for tuber crops such as cassava, yams and potatoes to enhance food security in the future is underestimated. In tuber crops there is the potential for a much higher ratio of edible to non-edible components than in above ground grain and bean crops such as rice, wheat, maize or soybean....

Abstract in portuguese 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 genito (more) ras 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. Abstract in english 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 hybrids, in randomized complete block design, with four replicate (more) s, in São João do Triunfo and Londrina, PR, Brazil. There was genotype x location interaction for most characters, predominantly from the general combining ability x location interaction. The best estimates of general combining ability of the synthetic group were observed for ST09 and ST04 and, in the variety group, for MC45 and IAPAR 50, taking into consideration the set of traits and locals. The bests crosses (MC34 x ST04, IAPAR 50 x ST07, MC47 x ST09, MC45 x ST02, MC51 x ST04, and MC45 x ST01) had positive estimates of specific combining ability for grain yield in both locals. There are crosses with potential to develop new maize varieties with better grain yield, plant height, ear position, percentage of damaged ears and of lodging and broken stalks than individual maize landraces, and more similar to the performance of commercial corn hybrids.

Abstract in portuguese Este experimento foi conduzido em Ames, Iowa, US durante o ano agrícola de 1994, tendo como objetivo avaliar se a macho-esterelidade genético-citoplasmática pode ser utilizada para aumentar o rendimento de grãos de milho em diferentes populações de planta. Quatro genótipos foram utilizados: um híbrido (NK 6330) e uma linhagem, ambos em suas versões fértil e macho-estéril. Cada genótipo foi avaliado em duas densidades de semeadura, equivalentes a 25.000 e 75.00 (more) 0 pl.ha-1. Os híbridos produziram maiores rendimentos de grão do que as linhagens nas duas populações utilizadas. O rendimento de grãos por área foi maior em 75.000 do que em 25.000 pl.ha-1. Nenhuma diferença significativa em termos de rendimento de grãos, número de espigas por planta, número de grãos por espiga, comprimento e número de ramos do pendão, foi observada entre genótipos férteis e macho-estéreis, independentemente da população de plantas. As versões férteis apresentaram pendões mais pesados do que os genótipos macho-estéreis. A adequada distribuição da precipitação e a alta fertilidade do solo possivelmente diminuíram a competição entre o pendão e as espigas, minimizando os benefícios da supressão genética da produção de pólen sobre o rendimento de grãos. Abstract in english This experiment was conducted in 1994 at Ames, Iowa, US to test whether cytoplasmic male-sterility can be used to decrease barrenness and to increase grain yield of maize at two plant populations. Four genotypes were tested: a hybrid (NK 6330) and an inbred, wifh sterile and fertile counterparts. Each genotype owas evaluated at plant populations equivalent to 25,000 and 75,000 pl. ha-1. Hybrids produced higher grain yield than inbreds at both plant populations. Gram yield (more) was higher at 75,000 than at 25,000 pl. ha-1. No difference in gram yield, number of ears per plant, number of grains per ear, tassel length, and tassel number of branches was found between sterile and fertile counterparts of the inbred and hybrid, regardiess of plant population. Fertile genotypes bore heavier tassels at anthesis than their sterile counterparts. Adequate precipitation distribution and high fertility level in the soil probably decreased competition between tassel and ears, mitigating potential yield benefits of suppressing genetically pollen production.

An alternative approach for cattle manure management on intensive livestock farms is the composting process. An industrial-scale composting plant has been set up in northwest Spain for producing compost from cattle manure. Manure composting involved an increase in pH, electrical conductivity (EC), cation exchange capacity (CEC) and NO3(-)--N concentration, and a decrease in temperature, moisture content, organic matter (OM) content, NH4+--N concentration and C/N ratio. Cu, Zn and Ni concentrations increased due to the reduction of pile mass during the composting process. The resulting compost was applied to a field to study the viability of applying this compost combined with a nitrogen mineral fertilizer as a replacement for the mineral fertilization conventionally used for maize (Zea mays L.). The thermophilic phase of the composting process was very prolonged in the time, which may have slowed down the decomposition of the organic matter and reduced the nitrification process, leading to an over-short maturation phase. The humification and respirometric indexes, however, determined immediately after compost application to the soil, showed it to be stable. Compost application did not decrease the grain yield. A year later, soil pH, OM content and CEC were higher with the compost treatment. Total P, K, Ca and Na concentrations in compost-amended plots were higher than in mineral-fertilized ones, and no significant differences between treatments were found in soil concentrations of NH4+--N,NO3- --N, available P, Mg and B. Compost caused no heavy metal pollution into the soil. Therefore, this compost would be a good substitute for the mineral fertilizers generally used for basal dressing in maize growing. PMID:17624756

Abstract in portuguese O uso de dessecantes na cultura do milho pode trazer benefícios para os agricultores, especialmente visando a disponibilização antecipada do solo para implantação de uma nova cultura, assim como o oferecimento antecipado do produto colhido ao mercado. Dentre os dessecantes disponíveis comercialmente, os herbicidas paraquat e diquat merecem destaque. O objetivo deste trabalho foi avaliar a eficiência dos herbicidas paraquat e diquat, aplicados como dessecantes em di (more) versos estádios de desenvolvimento da cultura de milho, sobre parâmetros produtivos e incidência de doenças nos grãos de milho. O ensaio foi conduzido na Embrapa Milho e Sorgo, Sete Lagoas, MG, utilizando-se os seguintes tratamentos: aplicação de paraquat e diquat aos 14 e 7 dias antes e aos 7 dias depois do ponto de maturação fisiológica (MF), assim como na própria MF. Ambos os produtos foram aplicados na dosagem de 400 g ha-1. O cultivar de milho utilizado foi o BRS 3101. Aos 0, 3, 6, 9, 12 e 15 dias após a aplicação dos produtos foram coletados 30 grãos de seis espigas aleatórias, para determinação da umidade dos grãos e peso da matéria seca. Na colheita foram avaliados: altura da planta e da espiga, índice de espigas, produção de grãos e espigas e sanidade dos grãos. Os produtos testados não apresentaram diferenças de eficiência para a maioria dos parâmetros avaliados, embora visualmente tenha sido constatado que o paraquat age mais rapidamente do que o diquat na secagem do tecido foliar verde. Apesar disso, quando se detectou alguma diferença entre os dois produtos químicos, o diquat foi superior ao paraquat. Com relação às épocas de aplicação dos produtos, foi constatado que a aplicação dos dessecantes aos 14 dias antes da MF resultou em redução na produção de grãos, devido à diminuição no peso da matéria seca dos grãos, apesar de ter antecipado em dois dias a MF e em quatro dias a colheita. Esse fato ficou mais bem evidenciado com a aplicação do paraquat. A produção de grãos verificada nos tratamentos testemunhas se igualou à dos melhores tratamentos com os dessecantes. O uso do paraquat resultou em grãos com maior porcentagem de infecção por Fusarium subglutinans, patógeno causador dos grãos ardidos em milho. Com relação à época de aplicação dos dessecantes, 14 dias antes da MF foi a que tornou o milho mais suscetível ao ataque desse fungo. Abstract in english The use of desiccants on maize crop may benefit farmers, especially by anticipating soil availability for the establishment of a new crop, and for the earlier commercialization of the product. The herbicides Paraquat and Diquat are classified as desiccants and are the most prominent in the market. The objective of this work was to evaluate their effectiveness as desiccants applied before corn harvesting. The experiment was carried out at EMBRAPA-Milho e Sorgo, Sete Lagoas (more) , MG, Brazil, by using the following treatments: application of Paraquat and Diquat at 14 and 7 days before and 7 days after physiological maturity (PM) and application at PM. Both products were sprayed at doses of 400 g ha-1. The cultivar used was BRS 3101 and the parameters were evaluated at 0, 3, 6, 9, 12 and 15 days after application. Thirty maize grains were harvested from 6 ears for evaluation of grain moisture and grain dry matter weight. At harvesting, the parameters evaluated were: plant and ear height, ear index, grain and ear production and grain sanity. The desiccants evaluated did not cause any differential effects for most characteristics, although visually Paraquat was observed to act more rapidly than Diquat in destroying the green leaf tissue. Statistical differences detected between the two desiccants, revealed that Diquat was more efficient than Paraquat. Application of the desiccants at 14 days prior to PM reduced grain yield due to grain dry matter weight decrease. However, PM was anticipated by two days and harvesting by four days. This was more evident with Paraquat. Grain production obtained with control was similar to that obtained with the best desiccant treatments. The use of Paraquat also resulted in grains with greater incidence of Fusarium subglutinans, which causes "burnt grains" in maize. Desiccant application 14 days before PM made maize most susceptible to this fungus infection.

Maize (Zea mays L.) plants have been transformed to express a Cry1F insecticidal crystal protein originally isolated from Bacillus thuringiensis Berliner. This protein controls lepidopteran pests of maize, including the European corn borer, Ostrinia nubilalis (Hübner). As part of the safety assessment for crops containing transgenes, a compositional analysis of the food and feed is conducted. This analysis is designed to detect unintended changes in the nutrient and antinutrient content of the raw commodities produced by the crop due to the insertion of the genes into the genomic DNA of the plant (pleotropic effects). Samples of transgenic and nontransgenic maize forage and grain were collected from six field sites located in the U.S. and Canada. Forage samples were analyzed for proximates and minerals, and grain was further analyzed for fatty acids, amino acids, vitamins, secondary metabolites, and antinutrients. Results demonstrated that maize expressing the Cry1F protein was equivalent to nontransgenic maize with respect to these important components. Comparison of the variability within the nontransgenic and transgenic hybrid, as compared to composition values reported in the literature, suggest that factors other than transgenes may contribute more substantially to the composition of crops. PMID:15113183

Zearalenone is an estrogenic mycotoxin commonly found in grains throughout the world. A number of instrument- and antibody-based methods including enzyme-linked immunosorbent assays (ELISAs) have been developed to detect zearalenone (ZEN) and related toxins in commodities and foods. Although convenient, the commercial ELISAs for small molecules such as ZEN require a washing step to separate bound and unbound enzyme label before detection. In fluorescence polarization immunoassays, separation of bound and unbound label is not required, a property that reduces the time needed to perform the assays. We developed a fluorescence polarization immunoassay for ZEN in maize. When combined with a rapid extraction technique, the assay could be used to detect as little as 0.11 microg of ZEN g(-1) maize within 10 min. The assay showed cross-reactivity to the ZEN analogs zearalanone, alpha-zearalanol, alpha-zearalenol, beta-zearalenol, and beta-zearalanol of 195, 139, 102, 71, and 20%, respectively, relative to ZEN (100%). Recovery of ZEN from spiked maize over the range of 0.5 to 5 microg g(-1) averaged 100.2% (n = 12). The fluorescence polarization immunoassay results were comparable to those obtained with a liquid chromatographic method for the analysis of 60 naturally contaminated maize samples and maize samples amended with culture material. The fluorescence polarization immunoassay provides a rapid method for screening of maize for ZEN. PMID:15151248

Abstract in portuguese A disponibilidade de cultivares destinadas à produção de milho verde é muito escassa, havendo necessidade de se desenvolverem novos híbridos apropriados para esse segmento. O objetivo deste trabalho foi avaliar o desempenho de genótipos de milho visando à produção de grãos e o potencial de consumo in natura no Sul do Estado do Tocantins. Os tratamentos foram constituídos de 158 populações e duas cultivares comerciais como testemunhas. O delineamento experimen (more) tal utilizado foi blocos casualizados com quatro repetições, sendo avaliados: comprimento de espiga, diâmetro de espiga, formato da espiga, alinhamento de fileiras, cor da coroa do grão, tipo de grão, peso de 100 sementes e produtividade de grãos. Houve diferenciação dos genótipos para todas as características e para todas as variáveis há genótipos com características desejáveis visando ao mercado de consumo in natura. De acordo com os resultados, os genótipos 01-5; 02-1; 02-2; 02-3; 02-4; 10-5; 25-1; 32-1 e 34-4 são os que reúnem o conjunto de características mais favoráveis para o desenvolvimento de genótipos comerciais voltados para o consumo in natura, e os genótipos do programa de melhoramento de Milho da Universidade Federal do Tocantins possuem potencial produtivo e podem ser utilizados para o desenvolvimento de cultivares voltados para uso nas condições edafoclimáticas do Estado do Tocantins. As populações avaliadas possuem variabilidade para ser explorada nos programas de melhoramento visando a diferentes aptidões comerciais. Abstract in english The cultivars availability for green corn production is very scarce, so there is need to develop new hybrid appropriate for that segment. This work aimed to evaluate performance of corn genotypes to grain yield and potential of in natura consumption in south of Tocantins State. The experiment was planted in Gurupi-TO, on April 25, 2009. The treatments were 158 populations and two cultivars as witness. The experimental design was randomized block with four replications, we (more) re evaluated: ear length, ear diameter, ear format, alignment of rows, crown color of grain, grain type, 100 seeds weight and grain yield. There was a differentiation of genotypes for all characteristics and for all variables there are genotypes with desirable characteristics on market for in natura consumption. Thus, conclude that the genotypes 01-5; 02-1; 02-2; 02-3; 02-4; 10-5; 25-1; 32-1 and 34-4 have the aggregate of favorable characteristics for development of commercial genotypes for in natura consumption, moreover the corn genotypes of UFT maize breeding program have yield potential and can be used to cultivars development for use in Tocantins conditions. The evaluated populations have variability for exploration in breeding programs aiming different commercials uses.

Abstract in spanish Doscientas cincuenta y tres familias F2 de alta calidad de proteína (ACP) provenientes del CIMMYT (Centro Internacional de Mejoramiento de Maíz y Trigo) fueron evaluadas en dos ensayos diferentes en Menegua, una localidad ubicada en el departamento del Meta de los Llanos Orientales de Colombia. El diseño experimental utilizado fue de alpha lattice con 2 repeticiones y en cada ensayo se incluyó testigos ACP y normales. Los datos fueron analizados siguiendo el método R (more) EML (Restricted máximum Likelihood Method) del procedimiento GLM de SAS 9.1.3. Los criterios principales de selección fueron rendimiento de grano y textura de grano. Se seleccionaron 44 F2s con rendimiento superior al del testigo ACP y comparable al rendimiento de los testigos normales. La textura de grano de las familias seleccionadas fue semi-cristalino con buena dosis de genes modificadores lo que indica que el gen o2 está presente. El paso siguiente será seguir el proceso de autofecundación de las familias F2 hasta llegar a F5 en que se hará los cruzamientos con probadores a fin de identificar líneas deseables para la formación de híbridos y sintéticos. Abstract in english The objective of the work was to select genotypes with high quality protein maize (QPM) and adapted to acid soils. Corn populations F2 of QPM were evaluated in the eastern plains of Colombia, by the International Maize and Wheat Improvement Center (CIMMYT) México. Populations were divided in two groups of 70 and 90 genotypes. The experimental designs consisted on a Alpha Lattice of 10x7 and 10x9, with two repetitions, were. The main criteria of selection were grain yield (more) (t/ha) and texture of endosperm, as indicator of modifier genes. The experiments were analyzed using the procedures MIXED and GLM with the Maxima method Restricted Probability (REML) of SAS 9.1.3. With the Alpha Lattice of 10x7, the results indicated that under conditions of acidity, the best genotype, accession 54 with 4,86t/ha, was similar to the commercial hybrid H-108 check. This material showed good texture also. In the Alpha Lattice of 10x9, the commercial material with greater yield was HEZC- 318 (7.57 t/ha) and the best accession, 33 and 77 did not out yield it, but the texture was good. The evaluation for modification of endosperm with the light table, 44 families F2 showed the presence of the gene opaque 2 that transfers the ACP characteristics and high yield.

Abstract in portuguese O objetivo deste trabalho foi avaliar o efeito de variações no arranjo espacial de plantas sobre o perfilhamento, a área foliar e a produtividade do milho. Os experimentos foram implantados na primavera/ verão dos anos agrícolas 2007/2008 e 2008/2009. Os tratamentos consistiram de quatro densidades (três, cinco, sete e nove plantas por metro quadrado) e de três espaçamentos entre linhas (0,4, 0,7 e 1,0 m). Foram avaliados o índice de área foliar (IAF) e a produt (more) ividade de grãos do híbrido P30F53, além da contribuição dos perfílhos para esses caracteres. Em 2007/2008, não houve deficiência hídrica, o IAF na floração foi superior a 7 e os perfilhos contribuíram com 65% do IAF total, na menor densidade de plantas. Nesse ano, a produtividade de grãos (13,7 Mg ha-1) não foi afetada pelos tratamentos, e os perfilhos contribuíram com 44% da produtividade, na densidade de três plantas por metro quadrado. Em 2008/2009, houve restrição hídrica na pré?floração e no enchimento de grãos, o que diminuiu o perfilhamento e a contribuição dos perfilhos ao IAF. A produtividade de grãos, nesse ano, aumentou de 9,7 para 11,7 Mg ha-1 com o aumento na densidade de plantas, mas a contribuição dos perfilhos à produtividade foi menor. O perfilhamento aumenta a estabilidade fenotípica da produtividade de grãos frente a variações no arranjo de plantas. Abstract in english The objective of this work was to evaluate the effect of plant spatial arrangement on maize tillering, leaf area, and grain productivity. The experiments were carried out in the spring/summer of the 2007/2008 and 2008/2009 growing seasons. Treatments consisted of four plant densities (three, five, seven, and nine plants per square meter) and three row spacings (0.4, 0.7, and 1.0 m). The leaf area index (LAI) and grain yield of hybrid P30F53 were assessed, as well as the t (more) iller contribution to these characters. In 2007/2008, there was no water deficit, LAI values were higher than 7, and tillers contributed with 65% of total LAI at the lowest plant density. In this year, grain yield average (13.7 Mg ha-1) was not affected by treatments, and tillers contributed with 44% of total yield at the density of three plants per square meter. In 2008/2009, there was water deficit before flowering and during grain filling, which decreased tillering and tiller contribution to LAI. Grain yield in this year increased from 9.7 to 11.7 Mg ha-1 with increasing plant densities, but tiller contribution to grain yield was lower. Tillering increases phenotypic stability of grain productivity to variations in plant spatial arrangement.

Gray leaf spot incited by Cercospora zeae maydis, is an important disease of maize (Zea mays L.) world-wide. The objective of this research was to evaluate the effect of composted poultry and cattle manures on development of gray leaf spot and yield of maize. The effects of composted manures were compared with those of different sources of inorganic synthetic nitrogen fertilizers in two cropping seasons. Composted manures and mineral fertilizers were tested to supply the recommended rate of 60kgNha^-^1 and at the highest rate of 90kgNha^-^1. Fertilizer treated maize plants were more diseased than non-fertilized (control). Higher disease severity was observed in plots receiving high levels of inorganic N fertilizers. The severity of gray leaf spot varied with fertilizer types (P 0.05). Maiz...

Low soil fertility, stemborers (particularly, Chilo partellus) and Striga weeds (Striga hermonthica and Striga asiatica) are major limitations to production of maize in western Kenya. The ''Push-Pull'' technology (''PPT'') has been described as an appropriate innovative technology capable of addressing these constraints. The technology involves intercropping maize with Desmodium and planting Napier grass (Pennisetum purpureum) around the intercrop, but in the current study a modified PPT was used and Napier grass was not included. Field trials were conducted in two locations in western Kenya during 4 subsequent seasons to test the hypothesis that maize yield, the degree of Striga suppression and economic benefits of intercropping maize with Desmodium are affected by: (i) the related biomas...

A greenhouse study was conducted to investigate the rhizosphere effects on iron (Fe), phosphorus (P), nitrogen (N), potassium (K), calcium (Ca), zinc (Zn), and manganese (Mn) nutrition in peanut plants (Arachis hypogaea L.) by intercropping them with maize (Zea mays L.). In addition, we studied the release of phytosiderophores and the ferric reductase activity of roots, pH and acid phosphatases in the rhizosphere and bulk soil, and the secretion of acid phosphatases in roots. Our results revealed that shoot yields of peanut and maize plants were decreased by intercropping the plants, as compared to monocultured plants. Growing peanut plants in a mixture with maize, enhanced the shoot concentrations of Fe and Zn nearly 2.5-fold in peanut, while the Mn concentrations of peanut were little affected by intercropping. In the case of maize, the shoot concentrations of Fe, Zn and Mn were not significantly affected by intercropping with peanut. Intercropping also improved the shoot K concentration of peanut and maize, while it negatively affected the Ca concentration. In the intercropping of peanut/maize, the acid phosphatase activity of the rhizosphere and bulk soil and root secreted acid phosphatases were significantly higher than that of monocultured peanut and maize. In accordance, the shoot P concentrations of peanut and maize plants were much higher when they were intercropped with peanut or maize, respectively. The rhizosphere and bulk soil pH values were not clearly affected by different cropping systems. When compared to their monoculture treatments, the secretion of phytosiderophore from roots and the root ferric reducing capacity of the roots were either not affected or increased by 2-fold by the intercropping, respectively. The results indicate the importance of intercropping systems as a promising management practice to alleviate Fe deficiency stress. Intercropping also contributes to better nutrition of plants with Zn, P and K, most probably by affecting biological and chemical process in the rhizosphere. PMID:17467283

Clarification of influencing factors (cultivar planted, cultivation management, climatic conditions) affecting yields of summer maize ( Zea mays L.) would provide valuable information for increasing yields further under variable climatic conditions. Here, we report actual maize yields in the Huanghuaihai region over the past 50 years (1957-2007), simulated yields of major varieties in different years (Baimaya in the 1950s, Zhengdan-2 in the 1970s, Yedan-13 in the 1990s, and Zhengdan-958 in the 2000s), and factors that influence yield. The results show that, although each variety change has played a critical role in increasing maize yields, the contribution of variety to yield increase has decreased steadily over the past 50 years (42.6%-44.3% from the 1950s to the 1970s, 34.4%-47.2% from the 1970s to the 1990s, and 21.0%-37.6% from the 1990s to the 2000s). The impact of climatic conditions on maize yield has exhibited an increasing trend (0.67%-22.5% from the 1950s to the 1970s, 2.6%-27.0% from the 1970s to the 1990s, and 9.1%-51.1% from the 1990s to the 2000s); however, interannual differences can be large, especially if there were large changes in temperature and rainfall. Among climatic factors, rainfall had a greater positive influence than light and temperature on yield increase. Cultivation measures could change the contribution rates of variety and climatic conditions. Overall, unless there is a major breakthrough in variety, improving cultivation measures will remain important for increasing future summer maize yields in the Huanghuaihai region.

On sites where C4-plants have replaced C3-plants, changes in soil ?13C allow the turnover of C3- and C4-derived C to be separated. Studies of decadal scale turnover of soil C following conversion to C4-plants generally lack ?13C values for previous C4-residue inputs and assume that estimates of C4-derived soil C to be based on a fixed ?13C value. Further assumptions are that changes in the initial (time-zero) soil ?13C values are insignificant following conversion to C4-plants. We tested these assumptions by measuring: 1) the ?13C of annual samples of silage maize biomass (C4-plant) and winter wheat grains (C3-plant) grown during 1988 to 2006, and 2) the ?13C of soil kept under bare fallow during 1956 to 1983. The ?13C of plants was related to climate variables, and the impact of maize ?13C was based on estimates of maize-derived soil C using different approaches to establish the ?13C in maize inputs. The ?13C of both maize and wheat decreased with time, but the rate of change and annual variations were considerably larger for wheat than for maize. Maize as well as wheat ?13C was best related to year (probably reflecting a decrease in atmospheric ?13C) and the water balance during the active growth period. Using the smallest (?12.44‰) and the largest (?11.26‰) ?13C measured during 1988 and 2006, estimates of maize-derived C in soil after 18 years ranged from 13.2% to 14.2% of the soil total C. Despite a loss of 31% of the soil C pool under bare fallow, the increase in soil ?13C was significant only at P < 0.10. We conclude that annual variations in maize ?13C values and changes in the ?13C of the soil C fraction derived from the pre-conversion C3-vegetation have only little impact on estimates of maize-derived soil C that cover a few decades. For estimates covering several decades to centuries, the subtle but consistent changes in plant and soil ?13C need to be accounted for. The variability in ?13C in wheat grains suggest that the use of any fixed ?13C value for C3-residues in estimates of C turnover in soils onwhich C4-plants have been replaced by C3-plants can be associated with considerable uncertainty.

Abstract in portuguese São relatados os resultados obtidos no melhoramento do cultivar de milho IAC-1 pela introdução de linhagens prolíficas nesta população, que já vinha sendo melhorada há oito ciclos pelo método de seleção entre e dentro de famílias de meios irmãos. Para produção de grãos foi observado um progresso genético médio de 3,3% por ciclo, comparado com um progresso genético esperado de 7,2% por ciclo. Para índice-de-espigas foi observado um progresso genético d (more) e 8,9% e um progresso genético espe-rado de 1,9% por ciclo. Com a introdução de fatores de prolificidade, o índice-de-espigas aumentou consideravelmente superando inclusive o do híbrido duplo comercial utilizado como controle. Houve pequeno aumento da porcentagem de plantas acamadas e quebra-das, com o decorrer dos ciclos de seleção. Computando-se os ganhos obtidos inicialmente neste cultivar, houve em 10 ciclos de seleção um progresso acumulado de 28% para produção de grãos e de 10% para índice-de-espigas, sendo este último obtido quase exclusivamente após a introdução das linha-gens prolíficas. Abstract in english There are presented results of the improvement of the maize (Zea mays, L.) cultivars IAC-1, after the introduction of prolificacy in a population formerly improved for eight cycles by the modified ear-to-row procedure. It was obtained an average progress of 3.3% per cycle in grain yield, against an expected genetic progress of 7.2% per cycle. For the ear index a genetic progress of 8.9% per cycle was observed and an expected genetic progress of 1.9% per cycle was estimate (more) d. With the introduction of prolificacy factors, ear index increased considerably outyielding the commercial double hybrid control Lodging changed 'very little with the cycles of selection. The IAC-1 cultivars showed an accumulated progress of 28% for grain yield and 10% for ear index. The gain in ear index is mainly due to the prolific inbred lines introduced in the synthetic.

Abstract in portuguese Estratégia de manejo de plantas daninhas pode ser realizada de forma integrada com o método químico na redução da utilização de herbicidas na cultura do milho. O objetivo deste trabalho é avaliar o efeito do manejo integrado do espaçamento entre linhas, ou de híbridos de milho com características morfológicas distintas e redução dos níveis de herbicidas, para controlar plantas daninhas na cultura do milho. O experimento foi instalado em delineamento de bloc (more) os ao acaso, com quatro repetições, arranjado em um fatorial 2 x 2 x 5, em que: o primeiro fator foram os híbridos Penta (superprecoce, com folhas mais planas) e Flash (superprecoce com folhas mais eretas); o segundo fator foram os espaçamentos entre linhas de milho (0,45 e 0,9 m) e o terceiro fator os níveis de manejo de plantas daninhas (capinado, sem capina e atrazine + foramsulfurom + iodosulfuron nas doses de 3000+45+3, 2250+33,8+2,3 e 1500+22,5+1,5 g ha-1 i.a.). Foram avaliados a altura e o ângulo foliar vertical das plantas, o número de plantas daninhas e a matéria seca de plantas daninhas por área. O ângulo foliar de plantas de milho torna-se mais planófilo com a adoção de espaçamentos reduzidos entre linhas, mas outras características de plantas de milho estão envolvidas no desempenho dos espaçamentos. O uso do espaçamento de 0,45 m entre linhas não contribui para a redução dos níveis de herbicidas para a cultura, mas sua adoção beneficia o manejo de plantas daninhas e o rendimento de grãos do híbrido Flash, embora não seja vantajosa para o híbrido Penta. Abstract in english Strategies to weed control in maize cultivation can be combined with chemical control to provide reduction of herbicide use. The aim of this work was to evaluate integrated management of plant row reduction, use of corn hybrids with contrasting morphological characteristics and reduction of herbicide levels to weed control. The experiment was carried out in a completely randomized block design with four replications in a 2 x 2 x 5 factorial. The first factor was maize hyb (more) rids such as Penta (super-early season maize with flatter vertical leaf angle) and Flash (super-early season maize and more upright vertical leaf angle). The second factor was maize row width (0.45 and 0.90 m) and the third factor was the weed management system (hoeing, no hoeing, and atrazine + foramsulfurom + iodosulfuron at 3000+45+3, 2250+33.8+2.3 and 1500+22.5+1.5 g a.i. ha-1). It was evalued the plant height and vertical leaf of corn plants, the number and dry matter of weeds per area. The vertical leaf angle of corn plants became flatter with the adoption of reduced row spacing, but other characteristics of corn plants were involved in the performance of spacing. The use of the narrow row spacing did not contribute to reducing levels of herbicides, but narrow row spacing benefits ony the weed management and grain yield of hybrid Flash.

Fusarium populations were investigated in maize grains and their husks about six weeks before harvest in three maize fields in the Manawatu region of New Zealand. The role of litter and soil as reservoirs for these fungi was also examined. Two techniques were used to examine populations, dilution plating and direct plating. Using the dilution plating technique the highest overall populations were found in husks (mean 2.2 x 10(5)/g) and litter (mean 1.4 x 10(5)/g), while similar lower numbers of viable propagules were obtained from grain (mean 2.1 x 10(3)/g) and soil (2.8 x 10(3)/g). With this technique five Fusarium spp. were commonly isolated; F. graminearum (Gibberella zeae), F. culmorum, F. subglutinans, F. oxysporum and F. acuminatum, of which F. graminearum was the most abundant. With the direct plating technique 87% of grains were infected with Fusarium spp., with some grains being infected with more than one species. Segments from husks and litter, 70% and 43% respectively, were colonised by Fusariumr spp. F. graminearum was the most frequent species isolated from maize grain and husk segments (48.3 and 37.7% colonisation respectively). Other species, particularly F. culmorum and F. acuminatum, were also found to be common contaminants. A total of 15 Fusarium spp. was recovered from all material examined by both techniques. Cultures with characteristics resembling those of F. moniliforme were rarely observed. PMID:12715944

Abstract in spanish El objetivo de la presente investigación fue determinar el efecto de la densidad de población y de la fertilización nitrogenada sobre el contenido de clorofila, acumulación de materia seca y el rendimiento de grano de maíces normales y con alta calidad de proteína. El experimento se estableció en Roque, Celaya, Guanajuato, México, en el ciclo primavera-verano 2003, bajo un diseño de bloques al azar con arreglo factorial en dos fechas de siembra. La parcela grande (more) se asignó a las seis variedades, la parcela media a las densidades de plantas (60 000, 70 000 y 80 000 plantas/ha) y la parcela chica a la fertilización nitrogenada (0, 100 y 200 kg ha-1 de N); la unidad experimental fue de 11.25 m². La concentración de clorofila y la materia seca se evaluaron en cuatro fechas durante el ciclo vegetativo; la primera se determinó con el medidor de clorofila Spad 502, y la segunda al determinar el peso seco de dos plantas por unidad experimental. El rendimiento se estimó cuando el grano alcanzó la madurez fisiológica. Los niveles más altos de clorofila se obtuvieron con 100 y 200 kg ha-1 de N en los maíces de alta calidad proteínica y normal. Las plantas en densidades de 70 000 y 80 000 plantas/ha expresaron la mayor concentración de clorofila a los 90 días, con registros de 65 y 63 unidades Spad, respectivamente. Entre dosis de N, la mayor producción de materia seca se obtuvo con 100 kg ha-1 de N, con V2 QPM (237 g/planta); entre densidades, esta misma variedad con 80 000 plantas/ha produjo la mayor cantidad de biomasa (251.17 g/planta). El rendimiento medio de grano obtenido con la aplicación de 200 y 100 kg ha-1 de N en los maíces de alta calidad proteínica fue de 10.2 y 8.8 t ha-1 respectivamente, a diferencia de 11.8 y 10.9 t ha-1 obtenidos con V1 (maíz blanco normal) con las mismas dosis. El rendimiento de la variedad de alta calidad proteínica CMSQ993027 fue comparable con el del mejor testigo de grano normal. Abstract in english The objective of this research was to determine the effect of plant stand and nitrogen fertilization on chlorophyll content, dry matter accumulation and grain yield of high quality protein and normal maize. The trial was established in two planting dates, during the spring-summer season of 2003 at Celaya, Guanajuato, Mexico, using a factorial, split-split-plot, experimental design. Cultivars were assigned to large plots, plant stands to medium plots and the small plots we (more) re assigned to nitrogen fertilization rates on experimental units of 11.25 m². Chlorophyll content and plant dry matter were sampled four times during the crop cycle. Chlorophyll and dry matter determinations were made by using the chlorophyll meter Spad-502 and dry matter by taking two individual plants from each plot. Grain yield was estimated at harvest maturity. Highest chlorophyll levels in both high quality protein and normal maize were obtained with 100 and 200 kg ha-1 of N. Plant stands of 70 000 and 80 000 plants/ha showed the highest chlorophyll values at 90 days after planting with 65 and 63 Spad units, respectively. ForN rates, QPM V2 showed the greatest production of dry matter (237 g/plant) with 100 kg ha-1 of N. For plant stands this QPM V2 maize cultivar also produced the greatest amount of dry matter (251.17 g/plant) when planted at 80 000 plants/ha. Average yield of high quality protein maize varieties with 200 and 100 kg ha-1 of N was 10.2 and 8.8 t ha-1, respectively, in comparison with 11.8 and 10.9 obtained with V1 -white seeded normal maize- at the same N rates. The grain yield of high protein quality CMSQ993027 was similar to the best normal seeded check.

Following a request from Monsanto within the framework of Regulation (EC) No 1829/2003 on genetically modified food and feed, the Panel on Genetically Modified Organisms was asked to deliver a scientific opinion on the authorisation of the insect-resistant, glyphosatetolerant genetically modified maize MON 88017 x MON 810 (Unique Identifier MON88Ø17- 3 x MON-ØØ81Ø-6). In delivering its scientific opinion, the EFSA GMO Panel considered the application EFSAGMO- CZ-2006-33, additional information provided by the applicant (Monsanto) and the scientific comments submitted by the Member States. Further information from applications for placing the single insert lines MON 88017 and MON 810 on the market under EU regulatory procedures was taken into account where appropriate. The scope of application EFSA-GMO-CZ-2006-33 is for food and feed uses, import and processing of genetically modified maize MON 88017 x MON 810 and all derived products, but excluding cultivation in the EU. The EFSA GMO Panel assessed maize MON 88017 x MON 810 with reference to the intended uses and the appropriate principles described in the Guidance Document of the Scientific Panel on Genetically Modified Organisms for the risk assessment of genetically modified plants and derived food and feed. The scientific assessment included molecular characterisation of the inserted DNA and expression of the new proteins. A comparative analysis of agronomic traits and composition was undertaken and the safety of the newly expressed proteins and the whole food/feed was evaluated with respect to potential toxicity, allergenicity and nutritional quality. An assessment of environmental impacts and the postmarket environmental monitoring plan were also undertaken. Maize MON 88017 was developed to express a modified Cry3Bb1 protein derived from Bacillus thuringiensis subsp. kumamotoensis rendering maize MON 88017 resistant to certain coleopteran pests and the CP4 EPSPS protein derived from Agrobacterium sp. strain CP4 which provides tolerance to glyphosate. Maize MON 810 expresses the Cry1Ab insecticidal protein, derived from Bacillus thuringiensis subsp. kurstaki, which confers protection against lepidopteran pests such as the European corn borer (Ostrinia nubilalis) and species belonging to the genus Sesamia. Maize MON 88017 x MON 810 was produced by crosses between maize inbred lines containing MON 88017 and MON 810 events to combine resistance to certain coleopteran (MON 88017 trait) and lepidopteran (MON 810 trait) pests and to confer tolerance to glyphosate (MON 88017 trait). The molecular characterisation data established that the structure of the individual inserts was retained in the hybrid maize MON 88017 x MON 810. Appropriate analyses of the integration sites in maize MON 88017 x MON 810, including flanking regions, was carried out. The bioinformatic analysis demonstrated the absence of any potential new ORFs coding for known toxins or allergens. Based on results of the comparative analysis the EFSA GMO Panel concludes that maize MON 88017 x MON 810 is compositionally, phenotypically and agronomically equivalent to the non-genetically modified (GM) counterpart and conventional maize varieties, except for the presence of Cry3Bb1, CP4 EPSPS and Cry1Ab proteins in maize MON 88017 x MON 810. Based on the assessment of data available, including the additional information provided by the applicant in response to the EFSA GMO Panel’s requests for maize MON 88017 x MON 810, for the single events and for appropriate non-GM controls, the EFSA GMO Panel has found no indication that crossing of MON 88017 with MON 810 maize results in an interaction between the single events which causes compositional or agronomic changes. The Cry3Bb1 and CP4 EPSPS proteins expressed in the parental maize line MON 88017, and the Cry1Ab protein expressed in the parental maize MON 810 have been assessed previously and no safety concerns were identified. Given all the information provided, the EFSA GMO Panel concludes that interactions between the single events that might impact on food and feed safety are unlikely. The nutritional value of maize MON 88017 x MON 810 has been investigated in a feeding study with broilers which confirmed that the nutritional properties of maize MON 88017 x MON 810 would be no different from those of conventional maize. In conclusion, the EFSA GMO Panel considers that maize MON 88017 x MON 810 is as safe and as nutritious as its non-GM counterpart and that the overall allergenicity of the whole plant is not changed. The application EFSA-GMO-CZ-2006-33 concerns food and feed uses, import and processing. Therefore, there is no requirement for scientific assessment of possible environmental effects associated with the cultivation of maize MON 88017 x MON 810. There are no indications of increased likelihood of establishment or survival of feral maize plants in case of accidental release into the environment of maize MON 88017 x MON 810 viable grains during transportation and processing. The scope of the post-market environmental monitoring plan provided by the applicant is in line with the intended uses of maize MON 88017 x MON 810. In conclusion, the EFSA GMO Panel considers that the information available for maize MON 88017 x MON 810 addresses the scientific comments raised by the Member States and that it is as safe as its non-genetically modified counterpart with respect to potential effects on human and animal health or the environment. Therefore the EFSA GMO Panel concludes that maize MON 88017 x MON 810 is unlikely to have any adverse effect on human or animal health or on the environment in the context of its intended uses.

Barley (Hordeum vulgare) and wheat (Triticum aestivum) possess significant phytase activity in the mature grains. Maize (Zea mays) and rice (Oryza sativa) possess little or virtually no preformed phytase activity in the mature grain and depend fully on de novo synthesis during germination. Here, it is demonstrated that wheat, barley, maize, and rice all possess purple acid phosphatase (PAP) genes that, expressed in Pichia pastoris, give fully functional phytases (PAPhys) with very similar enzyme kinetics. Preformed wheat PAPhy was localized to the protein crystalloid of the aleurone vacuole. Phylogenetic analyses indicated that PAPhys possess four conserved domains unique to the PAPhys. In barley and wheat, the PAPhy genes can be grouped as PAPhy_a or PAPhy_b isogenes (barley, HvPAPhy_a, HvPAPhy_b1, and HvPAPhy_b2; wheat, TaPAPhy_a1, TaPAPhy_a2, TaPAPhy_b1, and TaPAPhy_b2). In rice and maize, only the b type (OsPAPhy_b and ZmPAPhy_b, respectively) were identified. HvPAPhy_a and HvPAPhy_b1/b2 share 86% and TaPAPhya1/a2 and TaPAPhyb1/b2 share up to 90% (TaPAPhy_a2 and TaPAPhy_b2) identical amino acid sequences. despite of this, PAPhy_a and PAPhy_b isogenes are differentially expressed during grain development and germination. In wheat, it was demonstrated that a and b isogene expression is driven by different promoters (approximately 31% identity). TaPAPhy_a/b promoter reporter gene expression in transgenic grains and peptide mapping of TaPAPhy purified from wheat bran and germinating grains confirmed that the PAPhy_a isogene set present in wheat/barley but not in rice/maize is the origin of high phytase activity in mature grains.

Abstract in spanish Las prolaminas (zeínas) representan la principal proteína de reserva en el grano de maíz y poco se conoce sobre su participación en la textura de la tortilla. Para determinar su efecto, se evaluaron 6 híbridos de tipo normal y 6 de calidad proteínica (QPM, por sus siglas en inglés). Las variables químicas incluyeron prolaminas, amilosa y almidón. Se determinó la viscosidad de las harinas y la textura de las tortillas en términos de la fuerza de ruptura a tensi? (more) ?n y elongación. El contenido de prolaminas en los maíces normales fue 64% más elevado en comparación con los QPMs. No se observó relación entre el contenido de prolaminas y las propiedades de viscosidad de las harinas, como tampoco se halló relación de esta fracción proteínica con la dureza de la tortilla, pero si con la elongación, que mostró una correlación negativa con la cantidad de prolaminas. Las tortillas con mejores características de textura fueron H-161 en maíces normales y H-143C en maíces QPM, ambos maíces presentaron los granos más pequeños dentro de su grupo. Los resultados muestran que un elevado contenido de prolaminas en el grano de maíz podría estar limitando la textura de la tortilla en términos de su elongación Abstract in english Effect of the prolamins in maize (Zea mays L.) grain on tortilla texture. The prolamins (zeins) are the main storage proteins in the maize grain. There are limited investigations related to their participation on tortilla texture. For determining their effect, normal (6) and Quality Protein Maize (QPM) (6) genotypes were used. The chemical variables comprised prolamins, amylose and starch in whole grain and endosperm. Viscosity of the raw endosperm flour was determined as (more) well as the tortilla texture, expressed in terms of tension force and elongation. Prolamin content in the normal maizes was 64 % higher than that in the QPMs. It was not observed any relationship between prolamin content and flour viscosity. The prolamin content was not related with tortilla hardness, measured as the tension force to rupture the tortilla, but a negative correlation was observed with tortilla elongation. The tortillas with the best texture characteristics were from H-161nomal maize and H-143 QPM maize, both genotypes showed the smallest grain in its respective gruop. According to the results obtained in the present work, a high prolamin content in maize grain could be affecting tortilla elongation

Inclusion of cereal grains in fish diets may induce changes in digesta characteristics with possible consequences for fish performance. Especially viscosity characteristics of the dietary ingredients may induce these changes. The aim of this study was to investigate effects of dietary cereal grains (maize, wheat, barley, rye) differing in viscosity on digesta characteristics (viscosity, dry matter and volatile fatty acids), nutrient digestibility and performance (feed intake and growth) in African catfish. We hypothesized that increased dietary viscosity will induce changes in digesta characteristics that are associated with reduced nutrient digestibility and growth performance. Five experimental diets were formulated by adding grains to a basal diet to obtain a range of dietary viscositie...

A long-term experiment was conducted on a highly acidic (pH 4.6), coarse-textured Ultisol in the high rainfall region of southeastern Nigeria in order to evaluate the requirement for and residual value of lime (Ca(OH)/sub 2/) to a continuous crop rotation, and to determine the fate of applied Ca in the soil profile. The initial lime rates used were 0, 0.5, 1, 2, and 4 t of Ca(OH)/sub 2/ per hectare. Maize (Zea mays) was planted in the first season and cowpea (Vigna unguiculata) in the second season under a no-tillage, stubble conservation system. Relatively low rates of lime are adequate to sustain yields in a continuous maize-cowpea rotation system. Liming at a rate of 0.5 t/ha maintained maize yield near maximum for 2 years after application. Sustained maize yields for 5 years or more were possible with a lime rate of 2 t/ha. Cowpeas performed well and showed strong tolerance to soil acidity when planted as a late second-season crop after maize without additional fertilizer application. The critical level of exchangeable Al ranged from 25 to 55% depending upon rate of chemical fertilizer as well as cowpea variety used. Leaching losses of Ca from the surface soil during the first 3 years were soil pH (H/sub 2/O) was <4.3 indicating that lime was leached as neutral Ca salts and had little effect in ameliorating subsoil acidity. 17 references, 5 figures, 5 tables.

Abstract in portuguese Inúmeros trabalhos têm demonstrado o efeito benéfico da adubação com silício sobre o acréscimo da produção de diversas culturas, como, por exemplo, arroz, cana-de-açúcar e batata. No entanto, são escassas as informações sobre os benefícios nutricionais do silício para a cultura do milho. Desta maneira, objetivou-se, neste estudo, avaliar o efeito de doses e épocas de aplicação de silício, via foliar, nas características agronômicas e na produtividade (more) do milho, cultivado no ano agrícola 2007/2008. O delineamento experimental adotado foi o de blocos casualizados, em esquema fatorial (4 x 3) + 1, com quatro repetições, envolvendo doses de silício (130, 260, 390 e 520 g ha-1 de Si) aplicadas via foliar, épocas de aplicação (2, 5 e 8 folhas expandidas) e uma testemunha (sem aplicação de Si). As variáveis analisadas foram altura das plantas e a inserção da primeira espiga, diâmetro de colmo, índice de clorofila foliar, teor foliar de silício, número de grãos por espiga, massa de 100 grãos e produtividade de grãos. O silício aplicado via foliar influenciou somente o teor foliar de Si. Abstract in english Numerous studies have shown the beneficial effect of silicon on the increased production of several crops, such as sugar cane, rice and potato. However, there is little information about the nutritional benefits of silicon to the maize crop. Thus, the aim of this study was to evaluate the effect of doses and timing of leaf application of silicon on the agronomic characteristics and grain yield of corn grown in the agricultural year 2007/2008. The experimental design was r (more) andomized blocks in factorial scheme (4 x 3) + 1, with four replications involving doses of silicon (130, 260, 390 and 520 g ha-1) by foliar application, time of application (2, 5 and 8 expanded leaves) and a control (without silicon application). The studied variables included: plant height, height of first ear, stem diameter, leaf chlorophyll content, leaf silicon content, number of grains per ear, weight of 100 grains and grain yield. Silicon supplemented via foliar application influenced only the variable leaf silicon content.

The aim of this research was to study the effect of the dual treatment of sorghum decortication and protease addition during liquefaction with a-amylase, on the concentration of free amino nitrogen (FAN), fusel alcohols and ethanol during yeast fermentation. A bifactorial experiment was designed to revise the differences among grains (maize, whole and 9.7% decorticated sorghum) and the effectiveness of protease addition during liquefaction. The decorticated sorghum was more susceptible to protein hydrolysis compared to the whole kernel sorghum due to its lower fiber content. The protease improved the levels of FAN approximately to 60% and 30% in the maize and sorghum mashes, respectively. The maize mash contained the highest amount of FAN followed by the decorticated and whole sorghum mash...

Abstract Given global heterogeneity in climate-induced agricultural variability, Tanzania has the potential to substantially increase its maize exports to other countries. If global maize production is lower than usual owing to supply shocks in major exporting regions, Tanzania may be able to export more maize at higher prices, even if it also experiences below-trend productivity. Diverse destinations for exports can allow for enhanced trading opportunities when negative supply shocks affect the partners' usual import sources. Future climate predictions suggest that some of Tanzania's trading partners will experience severe dry conditions that may reduce agricultural production in years when Tanzania is only mildly affected. Tanzania could thus export grain to countries as climate change i...

Abstract Differences in soil moisture and wetting pattern under different irrigation frequencies mean that vegetative growth and nitrogen use efficiency in maize can differ even when the same total amount of irrigated water is applied under different frequency regimes. The goal of this study was to evaluate the effects of drip irrigation frequency and its interaction with nitrogen fertilization on vegetative growth and nitrogen use efficiency of a maize crop at different growth stages and on grain quality at maturity stage in a sandy soil. The experiment was conducted for 2-years (2005 and 2006) using a randomized complete block split-split plot design with four irrigation frequencies (once every 2, 3, 4 and 5-days), two nitrogen levels (190 and 380-kg-N-ha-1) and two maize hybrids (three-...

The post-flowering stalk rots (PFSR) are a complex disease, which are widely distributed in almost all the maize growing regions across the globe. A number of fungi are involved in causing decay of the pith resulting in pre-mature wilting of the plants. Most of the commercially grown cultivars have shown a high level of disease incidence at the grain filling stage. A systematic breeding programme on PFSR was initiated in India in collaboration with Asian Regional Maize Program of CIMMYT. Under this programme, germplasm screening was carried out at four 'hot spot' locations in India for different diseases: Hyderabad (Cephalosporium maydis), Udaipur (Fusarium moniliforme), Ludhiana and Delhi (Macrophomina phaseolina). Across the locations, promising maize genotypes were artificially inoculat...

Abstract in portuguese Bilhões em dólares e em cultivos estão sendo desperdiçados, seja durante a secagem de grãos ou ainda devido à suscetibilidade à seca, ao frio, à condições salinas de cultivo e ao processamento de grãos de baixa qualidade. O milho é um modelo de cultivo para adaptação a mudanças no clima. O melhoramento para adaptação é mais eficiente quando é conduzido em condições de desafios ambientais nas quais os genótipos mais adaptados são prontamente identifi (more) cados e os mais estáveis são selecionados. O programa de melhoramento de milho da Universidade Estadual de Dakota do Norte (NSDU), nos Estados Unidos, está estrategicamente localizado para desenvolver produtos sob condições de clima extremo. Esse programa atualmente aproveita os ambientes do norte dos Estados Unidos que permitem avaliar germoplasma para caracteres de adaptação importantes como produção. O programa dá ênfase em adaptação de germoplasma e sua integração com o desenvolvimento de cultivar, particularmente aquelas que possuem alelos singulares que não estejam presentes nos genomas B73 e NAM. Projetos que enfoquem as demandas presentes e futuras por genótipos superiores que sejam tolerantes a mudanças climáticas nos Estados Unidos e em várias parte do mundo são vitais para a pesquisa agrícola. Abstract in english Billions of dollars and crops are being lost to drying high moisture grain; drought, cold, and salt susceptibility; and to processing poor quality grain. Maize is a model crop for adaptation to climate changes. Breeding for adaptation is best done under challenging environmental conditions where strengths and weaknesses are quickly identified and most stable genotypes are selected. The North Dakota State University (NDSU) maize breeding program is strategically located to (more) develop products under extreme weather. It currently exploits northern U.S. environments that allow screening for adaptation traits that are as important as yield. The program focuses on germplasm adaptation and its integration into cultivar development, particularly those carrying unique alleles not present in the B73 and NAM genomes. There is a need for projects that are vital to agricultural research and will meet present and future demands of superior genotypes tolerant to climate changes in the U.S. and abroad.

Abstract in portuguese O objetivo desse trabalho foi fazer a atualização na proposta de classificação dos coeficientes de variação (CV) para a cultura do milho e avaliar a qualidade dos dados dos artigos mais recentes publicados no Brasil. Os CV das diferentes variáveis aleatórias foram obtidos a partir da consulta de 143 artigos científicos publicados de 2005 e 2010. As faixas de classificação dos (CV) foram baseadas na média (m) e no desvio-padrão (DP) da seguinte forma: baixo; m (more) édio; alto; muito alto. Todos os cv das variáveis aleatórias apresentaram distribuição normal. Foi possível observar que para a maioria dos caracteres avaliados houve uma grande diferença entre a classificação proposta e a de Pimentel-Gomes. Houve melhoria significativa na qualidade experimental na cultura do milho para os principais caracteres produtividade de grãos, alturas de planta e espiga, número de espigas por planta e peso de espigas comerciais, sendo a única exceção o peso de 100 grãos. Conclui-se que as faixas de classificação de coeficientes de variação têm que ser específica para cada variável, é necessária atualização periódica da classificação dos coeficientes de variação e nos últimos 15 anos, no Brasil, a qualidade da experimentação com cultura do milho teve uma melhora significativa. Abstract in english The objective of this study was to update the ranking of the coefficients of variation (CVs) from maize experiments and evaluate the accuracy of the data from the latest Brazilian publications. We rank-ordered the CVs for grain yield, plant and ear heights, number of ears per plant, and weight of commercial ears, except for the weight of 100 grains. The data were obtained from 143 scientific papers published from 2005 to 2010. The classification was based on the average ( (more) m) and standard deviation (SD) and the CVs were ranked as low, intermediate, high and very high. All of the random variables had the CVs normally distributed. For most of the traits, we observed a large difference between the ranks from Scapim and Pimentel Gomes. In summary, the coefficients of variation have to be classified for each variable, significant improvement occurred in the accuracy of the national maize experiments in the last 15 years, and they still require periodic updating.

Abstract in english Good progress has been made in the super hybrid rice (Oryza sativa L.) breeding in China. However, rice yield not only depends on the genetic characteristics but also on the agronomic practices. No-tillage and direct seeding (NTDS) is a simplified cultivation technology that greatly simplifies both land preparation and crop establishment. Aiming to determine the grain yield performance of super hybrid rice under NTDS and to identify critical factors that determine grain y (more) ield, field experiments were conducted in Nanxian, Hunan Province, China in 2009 and 2010. Two super hybrid cultivars, Liangyoupeijiu and Y-liangyou 1, were grown under conventional tillage and transplanting (CTTP) and NTDS. Grain yield, yield components, biomass production, crop growth rate and biomass accumulation during sowing to heading (HD) and HD to maturity were measured for each cultivar. There was no difference in grain yield under NTDS and CTTP. However, grain yield differed with cultivar and year. Y-liangyou 1 produced 4 % higher grain yield than Liangyoupeijiu in 2009, whereas in 2010 both cultivars yielded similarly. Grain yields of both cultivars were higher in 2009 than in 2010. Higher grain yield of Y-liangyou 1 in 2009 was associated with higher spikelet filling (spikelet filling percentage and grain weight), which resulted from higher biomass production. Crop growth rate after HD was critical for biomass production by the super hybrid rice. We suggest that increasing the crop growth rate after HD is an effective approach to increase grain yield of super hybrid rice under NTDS.

Identification of 'critical thresholds' of temperature increase is an essential task for inform policy decisions on establishing greenhouse gas (GHG) emission targets. We use the A2 (medium-high GHG emission pathway) and B2 (medium-low) climate change scenarios produced by the Regional Climate Model PRECIS, the crop model - CERES, and socio-economic scenarios described by IPCC SRES, to simulate the average yield changes per hectare of three main grain crops (rice, wheat, and maize) at 50 km x 50 km scale. The threshold of food production to temperature increases was analyzed based on the relationship between yield changes and temperature rise, and then food security was discussed corresponding to each IPCC SRES scenario. The results show that without the CO2 fertilization effect in the analysis, the yield per hectare for the three crops would fall consistently as temperature rises beyond 2.5C; when the CO2 fertilization effect was included in the simulation, there were no adverse impacts on China's food production under the projected range of temperature rise (0.9-3.9C). A critical threshold of temperature increase was not found for food production. When the socio-economic scenarios, agricultural technology development and international trade were incorporated in the analysis, China's internal food production would meet a critical threshold of basic demand (300 kg/capita) while it would not under A2 (no CO2 fertilization); whereas basic food demand would be satisfied under both A2 and B2, and would even meet a higher food demand threshold required to sustain economic growth (400 kg/capita) under B2, when CO2 fertilization was considered.

Maize is the major food crop of East Timor. It is grown under subsistence farming and its yields are low (1.0-1.7tha^-^1), with production insufficient to meet national needs. The ''Seeds of Life'' project, operating since 2001, has introduced open-pollinated maize varieties from other countries via the International Maize and Wheat Improvement Center (CIMMYT) and evaluated them for their suitability in local farming systems. Firstly, introductions were screened for yield potential and farmer-acceptable traits in replicated trials on research stations. Then, best selections were provided to farmers for evaluation against their local varieties under their own cultivation practices. More than 1000 on-farm trials were conducted across all of the agro-ecological zones of East Timor from the 20...

Ryan MR, Mortensen DA, Bastiaans L, Teasdale JR, Mirsky SB, Curran WS, Seidel R, Wilson DO &Hepperly PR (2010). Elucidating the apparent maize tolerance to weed competition in long-term organically managed systems. Weed Research50, 25-36. Summary In a long-term cropping systems trial comparing organically and conventionally managed systems, organic maize production sustained crop yields equal to conventional methods despite higher weed levels. In 2005 and 2006, an experiment nested within the trial was conducted to gain insight into this apparent crop tolerance to weed competition. Density of mixed weed species was experimentally manipulated to achieve a broad range of weed infestation levels. Under standard management conditions, all cropping systems produced equivalent maize yields, even...

Abstract in portuguese Atualmente, os critérios utilizados no Sul do Brasil para definição da dose de nitrogênio (N) a ser aplicada no milho são o teor de matéria orgânica no solo, a expectativa de rendimento da cultura e as características da cultura antecessora. Embora apresente alta relação carbono:nitrogênio (C/N), a aveia preta é a espécie de cobertura de solo de inverno mais utilizada como antecessora às culturas comerciais de verão. Essa característica pode resultar em im (more) obilização do N do solo, deficiência de N na planta de milho e redução no rendimento de grãos. Embora na determinação da dose a ser aplicada sejam consideradas as espécies antecessoras, os avanços quanto à melhor época para aplicar N em cobertura em milho foram pequenos. Com o objetivo de avaliar a época mais adequada para aplicação da primeira dose de N em cobertura no milho cultivado em sucessão a espécies de inverno com distintas relações C/N, um experimento foi realizado em vasos em casa de vegetação em Porto Alegre-RS. Utilizaram-se colunas de solo não deformado, classificado como Argissolo Vermelho distrófico típico. Os tratamentos constaram de quatro sistemas de coberturas de solo de inverno (aveia preta, ervilhaca comum, nabo forrageiro e pousio) e três formas de manejo de N em cobertura (com aplicação de N nos estádios V3 ou V5 e sem aplicação de N em cobertura). O delineamento experimental foi o completamente casualizado, em esquema fatorial 4 x 3, com três repetições. Procedeu-se à análise de variância pelo teste F e à comparação de médias pelo teste de Tukey (p Abstract in english The criteria currently used in Southern Brazil for the definition of the nitrogen (N) rate to be applied in maize are based on the soil organic matter content, the expected grain yield and the characteristics of the previous crop. Although the carbon:nitrogen (C/N) ratio is high, black oat is the most commonly used winter species antecedent to commercial summer crops. This characteristic can result in soil N immobilization, N plant deficiency and reduced grain yield in ma (more) ize. Although the antecedent species are considered in the determination of the adequate N rate, little progress has been made regarding the best time for N side dressed application in maize. With the objective of evaluating the best time of the first rate of N side-dressed application in maize cultivated in succession to winter species with distinct C/N ratios, a greenhouse experiment was conducted in pots in Porto Alegre, Rio Grande do Sul, Brazil. Undisturbed columns of soil, classified as typical dystrophic Argisol (Rhodic Ultisol) were used. The treatments consisted of four systems of winter cover species (black oat, common vetch, oilseed radish and fallow) and three management forms of side-dressed N application (N applied in the growth stage V3, V5 and without N application). The experimental design was a completely randomized block, in a 4 x 3 factorial treatment combination, with three replications. Analysis of variance was performed using the F test and the treatment means were compared by Tukey's test (p

Abstract in portuguese Na região do Cerrado, parte da adubação de cobertura no milho poderia ser antecipada à semeadura do milho visando acelerar a decomposição de resíduos da cultura antecessora. Os objetivos deste experimento foram: a) avaliar a produtividade de milho em sucessão à nabo forrageiro e milheto, na presença e ausência de adubação nitrogenada de cobertura e b) avaliar a eficiência de recuperação de N-adubo na planta e quantificar a volatilização de N-NH3 do ferti (more) lizante nitrogenado aplicado em sistema plantio direto (SPD) e em solo preparado (SP). O delineamento experimental utilizado foi blocos casualizados, em esquema de faixas, com quatro repetições. Até o florescimento, a produção de massa de matéria seca (MMS) e acumulação de N na parte aérea do nabo forrageiro foi de, respectivamente, 2.274 e 53,0kg ha-1, sob SPD, e 2.546 e 61,6kg ha-1, sob SP. No caso do milheto, os resultados obtidos foram 5.202 e 107,8kg ha-1, em SPD, e 5.101 e 104,1kg ha-1 em SP. Até a semeadura do milho em SPD, após o acamamento das culturas de inverno, foram liberados 77,3 e 130,7kg ha-1 de N na sucessão nabo-milho e milheto-milho, respectivamente. Na condição de SP, as culturas de inverno foram incorporadas ao solo antes da semeadura do milho. Na cultura do milho, a perda por volatilização de N-NH3 foi inferior a 2,0% do N-aplicado em pré-semeadura (71,3kg ha-1 de N na proporção 4:1, uréia:sulfato de amônio) e 14 % do N aplicado (5kg ha-1) em cobertura (35,7kg ha-1 de N-sulfato de amônio), avaliadas em SPD e SP, na sucessão nabo-milho. Em SPD, a eficiência da fertilização foi 57,1 e 42,1% do N-aplicado na sucessão milheto-milho e nabo-milho, respectivamente. Em SP, 46,8 e 46,3%, respectivamente. A adubação nitrogenada promoveu um acréscimo médio de 2.396kg ha-1 de grãos na sucessão milheto-milho, em SPD, comparada à testemunha não adubada. Este acréscimo foi de 895kg ha-1 de grãos na sucessão nabo-milho, sob SPD, e de respectivamente, 1.166 e 166kg ha-1 de grãos nas sucessões milheto-milho e nabo-milho, em SP. Abstract in english In the Cerrado region a proportion of the top dressed N for corn might be applied to the previous cover crop. This could accelerate the decomposition rate and increase overall N availability to corn. Therefore, the objectives of this experiment were: a) to evaluate maize productivity after oil radish and millet grown in winter with and without nitrogen applied and b) to determine the efficiency of recovery of N fertilizer by corn and quantify the losses by volatilization (more) of ammonia of N fertilizers in no-tillage (NT) and conventional tillage (CT). The experimental design was a randomized complete block in strips with four replications. At flowering, the dry matter production and N accumulation of the oil radish were, respectively, 2,274 and 53.0kg ha-1 under NT, and 2,546 and 61.6kg ha-1 under CT. For millet the results obtained were 5,202 and 107.8kg ha-1 under NT, and 5,101 and 104.1kg ha-1 under CT. Until the seeding of the maize under NT, after desiccation by knife rolling the winter crops, 77.3 and 130.7kg N ha-1 were released in the sequences of oil radish - maize and of millet - maize, respectively. Under CT the winter crops were incorporated into the soil before the seeding of the maize. In the growth cycle of corn the losses of N via ammonia volatilization were less than 2.0% of the N applied at pre-seeding (71.3kg N ha-1 in a mixture urea:ammonium sulphate of 4:1) and 14% of the N at the 6-leaf stage (35.7kg N ha-1 of ammonium sulphate), evaluated in NT and CT in the sequence oil radish - corn. Under NT the fertilizer-N-use-efficiency was 57.1 and 42.1% of the N applied in the sequence millet - corn and oil radish-maize, respectively. Under CT these values were 46.8 and 46.3%, respectively. The application of N fertilizer caused a mean yield increase of 2,396kg grain ha-1 in the sequence millet-corn under NT compared to the non-fertilized control. These increase under CT was 895kg grain ha-1 in the sequence oil radish-corn under NT, and 1,166 and 166kg grain ha-1 in the sequences millet-corn and oil radish-corn, respectively.

carbon, icy grain mantles, and organic refractory grain mantles. Silicon carbide ... stars, yield an upper imit on the relat ve vo ume of organic grain mantles which _s about half .... velocity ion-grain collisions behind a .... known. Even estimates of the relative importance of hign mass stars versus low mass. 67 ... features (in PN ...

Wheat cultivar Haruyutaka, bred in Hokkaido, as a cultivar with improved genetic traits for production in western Japan, had a lower grain yield when grown in Yamaguchi in western Japan than Daichinominori, native to Yamaguchi. We examined the yield and grain growth of these two cultivars in the two areas in 2005/2006, 2006/2007 and 2007/2008 to elucidate their grain filling mechanisms under the two environments. When grown in Yamaguchi, Haruyutaka had a lower grain yield due to smaller grains than Daichinominori and when grown in Hokkaido, Daichinominori had a lower grain yield due to smaller grains than Haruyutaka. The slower grain growth, especially, at the later period of grain filling was considered to be the major cause of smaller grain in both cultivars, but it was more pronounced in Haruyutaka grown in Yamaguchi. Haruyutaka and Daichinominori ceased total dry mass production earlier when grown in the non-native area, Yamaguchi and Hokkaido, respectively, resulting in less supply of current assimilation products to grain growth. When grown in Yamaguchi, the amount of post-anthesis culm reserves, water soluble carbohydrate (WSC), was smaller in Haruyutaka than in Daichinominori, while they accumulated a similar amount of WSC in Hokkaido. The pattern of remobilization of WSC to grains was similar in both areas. However, the grain filling period was significantly shorter in the non-native area. These results suggested that in the non-native environment, the grain size is decreased due to slower grain growth, mainly due to less current assimilation, and shorter grain filling period.   

Abstract in portuguese A adubação nitrogenada é importante para potencializar a produtividade do milho safrinha, que se tornou a principal cultura de outono-inverno, semeada após a soja, nos seguintes Estados: Paraná, São Paulo, Mato Grosso do Sul, Mato Grosso e Goiás. Com o objetivo de avaliar a produtividade de grãos e outras características agronômicas do milho safrinha em função de doses e épocas de aplicação de N, foi realizado um experimento em Latossolo Vermelho Eutroférr (more) ico argiloso, em Dourados (MS), no período de março a agosto de 1998. Utilizaram-se cinco doses de N (30, 60, 90, 120 e 150 kg.ha-1), na forma de uréia em quatro épocas de aplicação: E1 (todo N na semeadura), E2, E3 e E4 (1/3 na semeadura e os restantes 2/3, quando a cultura apresentou quatro, oito e dez folhas completamente expandidas, respectivamente) e um tratamento sem adição desse nutriente. Os tratamentos foram arranjados como fatorial 5 x 4 + 1, no delineamento de blocos casualizados, com quatro repetições. Avaliaram-se a altura de inserção de espiga, altura de planta, teor de N foliar e produtividade de grãos. A adubação nitrogenada influenciou todas as características estudadas, sendo a dose de 120 kg.ha-1 de N a que proporcionou os melhores resultados. Verificou-se que, para doses até de 60 kg.ha-1 de N não há necessidade de se parcelar a adubação nitrogenada. O melhor parcelamento foi 1/3 do N na semeadura e 2/3 em cobertura, quando as plantas apresentavam quatro a oito folhas totalmente expandidas, para as doses de 90 e 120 kg.ha-1 de N. Abstract in english Nitrogen fertilization is an important factor for the increment of the out-of-season maize grains yield (sown after soybean harvest, in the autumn-winter season) in the States of Paraná, São Paulo, Mato Grosso do Sul, Mato Grosso and Goiás. An experimental trial was set up aiming at the evaluation of grain yielding potential and other agronomic characters of the out-of-season maize cultivar AG-3010, as a result of five N doses (30, 60, 90, 120, and 150 kg.ha-1) and fou (more) r ways of N application (E1= all N applied at sowing; E2, E3, and E4 = 1/3 of the total N applied at the sowing and 2/3 when the plants had four, eight, and ten expanded leaves, respectively). A randomized complete block design was used (5 x 4 + 1 factorial model), with four replications. Plant height, ear height, leaf dry matter, leaf N content and grain yield were scored in all experimental plots. The best results for all evaluated characters were achieved with 120 kg.ha-1 N fertilization, at the stage of four to eight expanded leaves, with 1/3 of N applied at the sowing. Also, up to 60 kg.ha-1 N, there was no need of fractioning the total N dosis.

The soybean cyst nematode, Heterodera glycines, is a serious yield limiting pest in both Canada and the USA. Management of the nematode relies on crop rotation with non hosts, usually maize, and planting of resistant cultivars. However, the cropping system produces soybean every other year and exert...

Maize (Zea mays Ganga-5, hybrid variety) was used as a substrate for ethanol production by batch fermentation using Zymomonas mobilis, 20% solids concentration, 72 h of duration, pH 5,5 and 30deg C were found most effective in yielding maximum alcohol and proved optimum for highest fermentation efficiency. (orig.).

Infection of ears of maize with Fusarium graminearum (FG) reduces yield and, more important, contaminate the harvest with mycotoxins. F. verticillioides (FV) is an economically important cause of ear rot. Among other mycotoxins, FV produces the fumonisins (FUM) and FG produces deoxynivalenol (DON) a...

Interspecific competitive relationships and their effect on yield have been analysed in the association of potato and maize, two species with contrasting patterns of root and shoot systems establishment. Greenhouse experiments were carried out under three configurations (NC: no interspecific competi...

Major feedstock sources for future biofuel production are likely to be high biomass producing plant species such as poplar, pine, switchgrass, sorghum and maize. One active area of research in these species is genome-enabled improvement of lignocellulosic biofuel feedstock quality and yield. To faci...

Spinetoram is a novel insecticide that belongs to the spinosyn class of insecticidal chemicals. The efficacy of spinetoram against numerous insect pest species in a variety of field crops has been well demonstrated. However, there are no data available for the effectiveness of spinetoram against stored grain insects. In the present study, we evaluated spinetoram as a grain protectant, against six stored-product Coleoptera. The species tested were: the rice weevil, Sitophilus oryzae, the lesser grain borer, Rhyzopertha dominica, the larger grain borer, Prostephanus truncatus, the confused flour beetle, Tribolium confusum, the granary weevil, Sitophilus granarius and the sawtoothed grain beetle, Oryzaephilus surinamensis. All species were tested at the adult stage, on wheat (or maize in the ...