Variations in protein concentration and nitrogen sources in different positions of grain in wheat

The distribution patterns of total protein and protein components in different layers of wheat grain were investigated using the pearling technique, and the sources of different protein components and pearling fractions were identified using (15)N isotope tracing methods. It was found that N absorbed from jointing to anthesis (JA) and remobilized to the grain after anthesis was the principal source of grain N, especially in the outer layer. For albumin and globulin, the amount of N absorbed during different stages all showed a decreasing trend from the surface layer to the center part. Whereas, for globulin and glutenin, the N absorbed after anthesis accounted for the main part indicating that for storage protein, the utilization of N assimilated after anthesis is greater than that of the stored N assimilated before anthesis. It is concluded that manipulation of the N application rate during different growth stages could be an effective approach to modulate the distribution of protein fractions in pearled grains for specific end-uses

Spraying exogenous hormones alleviate impact of weak-light on yield by improving leaf carbon and nitrogen metabolism in fresh waxy maize

Insufficient light during the growth periods has become one of the main factors restricting maize yield with global climate change. Exogenous hormones application is a feasible measure to alleviate abiotic stresses on crop productivity. In this study, a field trial was conducted to investigate the effects of spraying exogenous hormones on yield, dry matter (DM) and nitrogen (N) accumulation, leaf carbon and N metabolism of fresh waxy maize under weak-light stress in 2021 and 2022. Five treatments including natural light (CK), weak-light after pollination (Z), spraying water (ZP1), exogenous Phytase Q9 (ZP2) and 6-benzyladenine (ZP3) under weak-light after pollination were set up using two hybrids suyunuo5 (SYN5) and jingkenuo2000 (JKN2000). Results showed that weak-light stress significantly reduced the average fresh ear yield (49.8%), fresh grain yield (47.9%), DM (53.3%) and N accumulation (59.9%), and increased grain moisture content. The net photosynthetic rate (Pn), transpiration rate (Tr) of ear leaf after pollination decreased under Z. Furthermore, weak-light decreased the activities of RuBPCase and PEPCase, nitrate reductase (NR), glutamine synthetase (GS), glutamate synthase (GOGAT), superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) in ear leaves, and increased malondialdehyde (MDA) accumulation. And the decrease was greater on JKN2000. While ZP2 and ZP3 treatments increased the fresh ear yield (17.8%, 25.3%), fresh grain yield (17.2%, 29.5%), DM (35.8%, 44.6%) and N (42.5%, 52.4%) accumulation, and decreased grain moisture content compared with Z. The Pn, Tr increased under ZP2 and ZP3. Moreover, the ZP2 and ZP3 treatments improved the activities of RuBPCase, PEPCase; NR, GS, GOGAT; SOD, CAT, POD in ear leaves, and decreased MDA content during grain filling stage. The results also showed the mitigative effect of ZP3 was greater than ZP2, and the improvement effect was more significant on JKN2000

Auswirkungen von zeitweiliger Überstauung zu unterschiedlichen Entwicklungsstadien von Weizen und Raps auf Ertragsparameter und Nährstoffzusammensetzung

Staunässe ist ein abiotischer Stressfaktor für Kulturpflanzen, der zunehmend ökologisch und ökonomisch an Bedeutung gewinnt und die Getreideproduktion in den gemäßigten Breiten beeinträchtigt. In Deutschland steigt zunehmend die Anzahl von extremen Wetterereignissen mit Starkregen und ergiebigem Dauerregen. Dies führt zu einem erhöhten Ertragsrisiko der Landwirte, gegen das keine finanzielle Absicherung besteht. Das Hauptziel dieser Arbeit war daher, die Auswirkungen von zeitweiliger Staunässe auf die Kulturpflanzen Winterweizen und Winterraps unter feldähnlichen Bedingungen zu untersuchen. Es wurde gezeigt, dass Staunässeperioden im Winterweizen und im Winterraps zu Ertragsverlusten führen, die Höhe des Ertragsverlustes dabei abhängig vom Entwicklungsstadium ist. Eine Überstauung zu Schossbeginn resultierte im Winterweizen in Beeinträchtigungen der vegetativen Entwicklung und in transienten Nährstoffmängeln, führte, aufgrund der hohen Regene¬rations¬fähigkeit der Weizenpflanzen, aber nicht zu einem Ertragsverlust. Im Winter¬raps beeinträchtigte die Überstauung das Pflanzenwachstum, die Nährstoffaufnahme und die Blütenfertilität, was in einer reduzierten Anzahl der Schoten, einer verringerten Anzahl der Körner pro Schote und einem verminderten TKG resultierte und zum Ertragsverlust führte. Eine Überstauung zur Blüte führte im Weizen und im Raps durch die Beeinträchtigung der generativen Entwicklung zu Ertrags¬verlusten. Staunässeperioden beeinflussten auch die Qualität von Winterweizen und Winterraps. Spät überstauter Weizen bildete Schmachtkörner mit geringen Proteingehalten pro Korn. Außerdem veränderte sich die Protein¬zusammen¬setzung, was zu einer Veränderung der Backqualität führen könnte. Im Winterraps führten Staunässeperioden zu einem Anstieg des Ölgehalts im Raps¬samen. Der von der verarbeitenden Industrie geforderte Ölgehalt von 40 % konnte unabhängig von der auftretenden Staunässe erreicht werden. Die Fettsäurezusammensetzung veränderte sich nur geringfügig

Optimized winter wheat production in Kiev region of Ukraine : a case study on cultivation properties and management focusing on sowing date and nitrogen fertilization

Ukraine is the tenth largest wheat producer in the world but average yields are low, about 3 ton ha-1. A better understanding of growth conditions and factors limiting yield is importantin developing strategies to increase grain yield. This Master’s thesis examined the conditions for winter wheat cultivation (Grain Alliance strategy) in Berezan in the Kiev region of northern Ukraine, and the potential to increase crop yields. The wheat cultivation in seven nearby fields in Berezan was compared with one reference field in Uppsala in Sweden. The effect of sowing date was studied by determining plant development and growth in fields with different sowing dates. The effect of fertilization level was also studied in these fields. In the sowing date trials, the factors plants per square meter in late autumn and spring, shoots per plant in late autumn and spring, and plant weight in late autumn were measured. The yield-forming factors ears m-2, kernels per ear, grain size and grain yield were also measured.In the fertilization trials, only grain yield factors were measured. To determine the growing conditions the soil physical properties and water availability were measured. The development of the winter wheat was also simulated by a phenology model with data from local weather stations. The climate in Kiev is 3-5 ˚C warmer than for Uppsala during the period April-August. It results in more rapid plant development in Kiev compared with Uppsala and 4-5 weeks earlier maturity. Precipitation and evapotranspiration are higher in Kiev than in Uppsala. Soil conditions in the Kiev region are favourable, with good soil aeration and low bulk density combined with relatively high amounts of plant-available water. A normal year the amount of precipitation and soil water storage is adequate to supply the wheat with water and avoid drought on both the clay soil in the field in Uppsala and the silty loam in the fields in Kiev. The relatively high temperature and availability of water motivates a cultivation strategy with relatively high ear densities to achieve high yield, as ear size can be reduced by rapid plant development. If winter wheat is sown during the first 2-3 weeks of September there are good opportunities to use relatively low seed rates, as lower plant number can be compensated by tillering. If sowing is postponed quite high seed rates are justified. The early-sown winter wheat in this study had significantly greater biomass and tillering in autumn than late-sown wheat. Plant number was higher for late sowing dates, depending on higher seed rates. Both early- and late-sown wheat survived winter very well. Plant stand density was high in all the seven fields in Berezan, much higher than in the reference field in Uppsala. There was a large reduction of tillers in spring, but final number of ears was still relatively high. As variety and seed rates varied between trials with different sowing dates, it is not possible to claim significant effects of grain yield depending on sowing date. Kernel size was normal but ear size was relatively low, and was the yield factor with highest correlation to yield level in the different fields. Yield level was generally high, even in treatments with low fertilization, and yield increases for high fertilization rates (above 160 kg N ha-1) were relatively low. This indicates quiteextensive mineralization from the soil. No significant difference in yield level was found between wheat fertilized with equal amounts of nitrogen applied in autumn and spring compared with spring only. From a crop perspective, nitrogen from fertilizer must be available at the beginning of stem jointing, when the need is highest. By dividing the fertilization into 2-3 application occasions from early spring to heading, it is possible to adjust the nitrogen rate to development and growth conditions to match stand requirements. The Grain Alliance cultivation strategy gave considerably higher winter wheat yield than the average for the Kiev region, probably due to more intensive management, with the crop not limited by fertilizer deficiency or plant protection problems. Using varieties that combine hardiness and high yield potential, establishing plant stands of sufficient density and performing field operations, for example sowing and fertilization, at the right time are issues to work with for further improvement of winter wheat yield in Ukraine

Genetic Mapping of Yield and Normalized Difference Vegetative Index in Soft Red Winter Wheat (Triticum aestivum L.)

Wheat is the most widely cultivated cereal crop, being grown on 17% of the global crop land and as such must be adapted to an array of environmental stresses. In order to become a variety, wheat breeding lines must be tested across a range of environments for both high productivity and stability. Quantitative trait loci (QTL) mapping and indices are tools that can aid plant breeders in the selection of superior lines. Soft red winter wheat accounts for 20% of the total wheat production in the United States, being grown in the southeastern U.S. predominantly along the Mississippi River. However, there are currently no reports of QTL associated with grain yield and test weight in U.S. soft red winter wheat. The objective of this study was to identify QTL associated with grain yield, test weight and related traits to aid breeders in the southeastern U.S to better understand the genetic control of adaption to this region that can lead to higher production and producer return. This study was also aimed to assess the ability of normalized difference vegetative index (NDVI) to monitor changes in crop development over the growing season as well as to identify QTL influencing these changes. A recombinant inbreed line (RIL) population derived from a cross between two elite cultivars, `Pioneer 26R61\u27 and `AGS 2000\u27, was grown in six different testing sites from 2011-2014 for a total of twelve site-years. A randomized complete block design was used with two replications per location. Mean grain yield for the RILs ranged from 339 g m-2 to 716 g m-2 and test weight from 69 kg hl-1 to 80 kg hl-1. A total of 42 QTLs were detected for yield, test weight, heading date and height. Eleven yield QTL were identified, explaining from 1.8 to 8.5% of the phenotypic variation and contributed by both of the parental lines. Yield QTL explaining the most variance were located on chromosome 5B and were also associated with the favorable allele from AGS2000 for early heading. Eight QTL were identified for test weight, with the largest effect locus on 5D explaining 7.1% of the phenotypic variance. For the NDVI study, NDVI measurements were repeated on multiple days throughout the growing season with at least one measurement taken during vegetative and grain-filling stages at seven Arkansas site-years. Based on the accumulated growing degree days, NDVI measurements were grouped into seven development stages. In addition, vegetative biomass samples were harvested during early plant development and biomass at maturity was estimated from 50 tillers harvested at ground level prior to whole plot harvest. Genetic variation and heritability of NDVI increased throughout the growing season as did correlations between NDVI and biomass or yield. Significant correlations ranged from r = -0.32 to 0.37 for NDVI development stages with yield, biomass at maturity and vegetative biomass. For individual environments, particularly those that had low production, correlations were found to be as high as r = 0.72 for late season measurements of NDVI and yield. QTL for NDVI were found to be highly pleiotropic and were clustered in 14 genome regions across 11 of the 21 wheat chromosomes. Six of the 14 regions co-localized for both NDVI and biomass, with individual QTL explaining up to 14.7% of the phenotypic variation for NDVI. Results presented here can aid breeders in future development of high yielding cultivars through marker assisted breeding and in targeting growth and development to meet the demands of a diverse range of growing environments

Water-wise Rice Production

Rice is a profligate user of water. It takes 3,000–5,000 liters to produce 1 kilogram of rice, which is about 2 to 3 times more than to produce 1 kilogram of other cereals such as wheat or maize. Until recently, this amount of water has been taken for granted. Now, however, the water crisis threatens the sustainability of the irrigated rice ecosystem. In Asia, 17 million ha of irrigated rice areas may experience ‘physical water scarcity’ and 22 million ha ‘economic water scarcity’ by 2025. To safeguard food security and preserve precious water resources, ways must be explored to grow rice using less water. IRRI, together with Plant Research International of Wageningen University and Research Centre, organized a thematic workshop on Water-Wise Rice Production held 8-11 April 2002 at IRRI, Los Baños, Philippines. The objectives were to present and discuss the state-of-the-art in the development, dissemination, and adoption of water-saving technologies at spatial scales ranging from the field to irrigation system. This book contains the papers presented at the workshop

Evaluating the impacts of waterlogging stress on cowpea (Vigna unguiculata L.) growth traits and physiological performance

The progressive increase in the global population and the rapidly changing climate have put unprecedented pressure on crop production. Cowpea is one of the world’s most important leguminous crops, contributing to food security and environmental sustainability. However, cowpea productivity is limited due to waterlogging stress. The main objective of this study was to explore physiological and biochemical mechanisms to understand how cowpea genotypes respond to waterlogging stress. Four studies were conducted in controlled and field conditions to achieve these objectives. Study 1 characterized the waterlogging tolerance of 30 cowpea genotypes in a controlled environment using 24 morphophysiological parameters with waterlogging tolerance coefficients and multivariate analysis methods. 10% of the genotypes exhibited high tolerance to waterlogging stress, and the genotypes UCR 369 and EpicSelect.4 were identified as the most and least waterlogging tolerant, respectively. Study 2 evaluated the key parameters influencing carbon fixation of UCR 369 and EpicSelect.4 at the reproductive stage. The less tolerant EpicSelect.4 experienced high downregulation of stomatal and non-stomatal limiting factors during waterlogging and recovery, resulting in decreased carbon assimilation rates. UCR 369 rapidly developed adventitious roots, maintained biomass, and restored pigments and metabolites to sustain photosynthesis. A two-year field experiment was conducted in study 3 to quantify the effects of waterlogging on the yields, physiology, and biochemistry of cowpeas at different growth stages. The most apparent impact of waterlogging stress occurred at the reproductive stage, followed by the vegetative and maturity growth stages. Studies suggest that diverse cowpea genotypes have distinct physiological and biochemical mechanisms in response to waterlogging stress. In addition, the tolerant genotypes and traits identified herein can be used in genetic engineering and cowpea breeding programs that integrate increased yield with waterlogging stress tolerance