Increase In Grain Protein Content Research Articles

Developing early-estimating normalized difference vegetation index calibrations for grain yield and technological quality of bread wheat in semi-arid rainfed conditions

In this study, the usability of in-season estimated yield (INSEY) and optical-read sensor Normalized Difference Vegetation Index (NDVI) at the Zadoks30 stage (Z 30) in rainfed conditions for predicting bread wheat grain yield and technological quality was evaluated. Data from nitrogen fertilizer application field trials conducted in eight consecutive years in 14 environments were used to develop regression equations to predict yield and some quality attributes in rainfed conditions. The trials were divided into two groups, low NDVI (LNE) and high NDVI (HNE), according to the magnitude of NDVI. Technological bread quality parameters and yield were higher in the HNE. The increase in grain protein content (GPC) and macro SDS (MSDS) sedimentation against nitrogen rates became significant beyond 60 kg N ha−1 in the LNE and 30 kg N ha−1 in the HNE. Linear relationships occurred between NDVI and observed values of grain yield (R2 = 0.743, p<0.001) and GPC (R2 = 0.963, p<0.001). The use of NDVI and INSEY values at Z 30 stage facilitated the development of equations capable of predicting grain yield, GPC, and gluten quality. The developed equations can be used in the nitrogen fertilization strategy during the tillering stage to achieve specific yield and protein.

Breeding wheat for organic farming: Can the high grain protein gene Gpc-B1 help to tackle challenges in view of end-use quality?

Organic farming contributes to sustain healthy ecosystems, but challenges such as lower crop yields and supply of the nitrogen needs of crops remain. Wheat is the most important organic arable crop in Europe and grain protein content is the main quality trait also for grading organic wheat despite that high baking quality can be also realized at lower protein contents. Hence, breeding of organic wheat varieties that realize a stable high grain protein content even at lower nitrogen availability is of utmost importance to guarantee income of organic wheat growers. A major QTL for high grain protein content was identified in wild emmer and transferred into bread wheat. We tested six different wheat genetic backgrounds varying for the presence/absence of the functional Gpc-B1 allele in multi-location trials in Central Europe for their performance under organic growing. The increase in grain protein content caused by the functional Gpc-B1 allele was present in almost all genetic backgrounds, however, was not consistent across all tested quality traits. None the less, the functional Gpc-B1 allele may play a major role to increase the stability of organic wheat to reach minimum requirements by traders and processors with respect to grain protein content.

OsG6PGH1 affects various grain quality traits and participates in the salt stress response of rice.

Cytoplasmic 6-phosphogluconate dehydrogenase (G6PGH) is a key enzyme in the pentose phosphate pathway that is involved in regulating various biological processes such as material metabolism, and growth and development in plants. However, it was unclear if OsG6PGH1 affected rice grain quality traits. We perform yeast one-hybrid experiments and reveal that OsG6PGH1 may interact with OsAAP6. Subsequently, yeast in vivo point-to-point experiments and local surface plasmon resonance experiments verified that OsG6PGH1 can bind to OsAAP6. OsG6PGH1 in rice is a constitutive expressed gene that may be localized in the cytoplasm. OsAAP6 and protein-synthesis metabolism-related genes are significantly upregulated in OsG6PGH1 overexpressing transgenic positive endosperm, corresponding to a significant increase in the number of protein bodies II, promoting accumulation of related storage proteins, a significant increase in grain protein content (GPC), and improved rice nutritional quality. OsG6PGH1 positively regulates amylose content, negatively regulates chalkiness rate and taste value, significantly affects grain quality traits such as appearance, cooking, and eating qualities of rice, and is involved in regulating the expression of salt stress related genes, thereby enhancing the salt-stress tolerance of rice. Therefore, OsG6PGH1 represents an important genetic resource to assist in the design of high-quality and multi-resistant rice varieties.

Enhancing wheat protein through low-water-fertility under climate change without yield penalty

Efforts to enhance wheat quality without compromising yield are imperative in the context of climate change. However, the quantification of management measures that simultaneously elevate wheat protein concentration, especially its components, while maintaining yield has been scarcely addressed due to its inherent complexity. In this study, we investigated the impact of various combinations of sowing dates, nitrogen fertilizer, and irrigation on improving the protein concentration of strong gluten winter wheat (Jimai 20) using a validated wheat grain protein component simulation model in Tai'an, Shandong. Our results indicate that climate change between 2031 and 2060 is anticipated to cause a significant decrease in wheat yield and an increase in wheat protein concentration compared to the period from 1981 to 2010. Albumin and globulin are projected to decrease, while gliadin and glutenin are expected to increase, respectively. The average glutenin-to-gliadin ratio in the baseline is 1.096, whereas in scenarios SSP2–4.5 and SSP5–8.5, it is 1.093 and 1.102, respectively. Adapted measures can effectively synergize to enhance both wheat protein quality and yield under climate change. Specifically, delaying sowing and reducing nitrogen application to 210–240 kg·ha−1 with 200–240 mm of irrigation contribute to maintaining yields at the current conventional treatment level. Furthermore, these practices result in a 3.89 % and 0.13 % increase in grain protein concentration, and a 1.19 % and 6.02 % enhancement in the glutenin-to-gliadin ratio under scenarios SSP2–4.5 and SSP5–8.5, respectively, compared to conventional treatments. This comprehensive analysis provides valuable insights into practical strategies for synergistically improving wheat yield and protein quality in the face of climate change.

Effect of Nitrogen Nutrition Stress on Grain Weight, Starch Quality in Bread Wheat

Grain weight in wheat is influenced by genetics and the environment, with nitrogen (N) nutrition playing a crucial role by improving grain filling and dry matter accumulation. Starch constitutes 60 to 70% of wheat grain dry matter, consisting of amylose and amylopectin. Amylose/amylopectin ratio determines the resistance nature of the starch and glycaemic index, which are important for human health. Nitrogen nutrition affects dry matter accumulation in wheat grain by influencing starch biosynthesis and enzymes involved in it. In this study, four wheat genotypes (HB-208, VL-829, chotilerma and HD-2967) with varied grain weights were grown under optimum nitrogen (ON) and low nitrogen (LN) conditions. The effect of nitrogen stress on grain weight; starch, amylose and amylopectin content were studied in these genotypes. Further, the important enzymes linked to amylose and amylopectin biosynthesis activity were also assayed in grains during the active grain-filling stages. HB-208 showed the highest grain weight, followed by VL-829, HD-2967 and chotilerma. Under nitrogen stress, grain weight was significantly reduced in HB (29%) and VL (25%), whereas no reduction was observed in case of HD and CL. Genotypic difference in grain filling was observed, where maximum starch accumulation in HD was observed before 21 days after anthesis (DAA) whereas, after 21 DAA in VL. We observed an increase in grain protein content under nitrogen stress in all three genotypes except HD. Among the two components of starch, amylose content was significantly reduced across the genotype under N stress, whereas amylopectin was unchanged in HB and VL and increased in HD and CL. Reduction in amylose resulted to starch reduction in HB and VL, which also corroborated with grain weight reduction. AGPase enzyme activity at 21 DAA was reduced in HB and VL, resulting in decreased starch content.

Climate warming extends the effective growth period of winter wheat and increases grain protein content

Climate warming causes an impact on the protein supplied to grains by affecting the winter wheat growth period and yield formation; however, research on the effects of warming on protein formation of winter wheat grains is limited. We investigated this phenomenon by conducting no-tillage (NT) and conventional tillage (CT) field warming trials in the North China Plain for four consecutive years (2017–2020). The results showed that warming significantly advanced the re-greening period and extended the effective growth period of winter wheat. Warming also improved the physiological characteristics of winter wheat as well as N accumulation in the stems and leaves during anthesis, facilitating the transport of N to the grains. Moreover, warming reduced the number of fertile spikelets in winter wheat and diverted N that would otherwise be supplied to produce more grains to the final effective grains, resulting in a significant increase in grain protein content (15.75% in CT, 19.11% in NT; p < 0.05). Our findings suggest that winter wheat can partially counteract the adverse effects of climate warming on its grain protein content. This study further elucidates the effect of climate warming on the protein content of winter wheat grains.

Different Crop Rotations and Residue Levels as They Affect Corn Grain, Residue Production, and Nutrient Concentration

The consumption of corn-based foods is a good alternative for human health due to their high content of proteins, essential amino acids and polyunsaturated fatty acids of the omega-3 family. The present study evaluated the effect of two medium-term canola (Brassica napus L.)-corn (Zea mays L.) and bean (Phaseolus vulgaris L.)-corn rotations with four residue incorporation rates (0%, 50%, 100% and 200% of the preceding crop) on corn grain yield, residue production, nutrient concentration and extraction after two rotation cycles in a volcanic soil of south-central Chile. Results indicated that grain yield ranged from 17.04 to 17.40 Mg ha -1 , and residue production ranged from 16.41 to 16.50 Mg ha -1 , being unaffected by the preceding crop. Residue incorporation rates had no effect on grain yield and residue production. The preceding crop affected the concentration and extraction of some nutrients in grain and residue. Residue rate affected the concentration and extraction of some nutrients in grain only. Ca distribution in corn grain was negatively affected by the preceding bean crop and increased residue incorporation rate. Nutrient concentration in grain ranged from 1.33 to 1.36% for N, 0.33% for P, 0.53 to 0.54% for K, 0.008 to 0.011% for Ca, 0.14% for Mg, and 0.087 to 0.092% for S. The ranking of total macronutrient extraction in the corn crop was K &gt; N &gt; Ca &gt; P &gt; Mg &gt; S. The extraction means ranged from 320.0 to 325.8, 56.0 to 57.1, 364.7 to 373.7, 86.5 to 99.3, 39.4 to 42.4, and 22.6 to 23. 7 kg ha -1 , while grain nutrient partitioning coefficients ranged from 64.5 to 66.8, 90.1 to 90.9, 23.1 to 23.7, 1.3 to 2.0, 50.8 to 57.5, and 60.3 to 60.6 for N, P, K, Ca, Mg, and S, respectively. The use of bean as a previous crop allowed an increase in grain protein content (8.56 vs. 8.30%) with respect to the canola crop.

Global analysis of nitrogen fertilization effects on grain zinc and iron of major cereal crops.

Human zinc (Zn) and iron (Fe) deficiencies can partly be alleviated by enhancing cereal concentrations of these micronutrients. Soil nitrogen (N) levels codetermine cereal grain yields and Zn and Fe nutrition of plants and grains. Grain Zn and Fe concentrations have been reported to be affected by both yield dilution and enhanced acquisition and grain allocation of Zn and Fe. A global meta-analysis of 100 publications concerning wheat, maize, and rice providing 785 records of Zn and 506 records of Fe allowed us to assess their relative importance and quantify the concentrations and bioavailability of Zn and Fe in major cereal grains over a wide range of N fertilization levels. Compared with the no N controls, N application significantly increased grain Zn and Fe concentrations in all crops except maize Zn. The increase in grain protein concentration correlated positively with the increases in Zn and Fe concentrations in all cereals except Zn in maize. In rice, the grain Zn and Fe concentration increase was independent of the rate of N applied. Grain concentrations of Zn and Fe in wheat and Fe in maize were positively correlated with N rate but were only higher than those in the controls above 40–60 kg N ha−1. At lower N rates, the dilution effect was thus stronger than the enhancement effect. N supply had a larger effect on Zn and Fe concentrations in loamy textured soils or at lower soil available N and phosphorus (P), or higher soil organic matter and available Zn contents or with P and Zn fertilization, but the effect sizes differed among crops. Reductions in phytic acid concentration after N fertilization occurred in wheat, potentially improving micronutrient bioavailability. Thus, our findings indicate that N fertilization could be managed in ways that simultaneously support high grain yields and enhance nutritional quality for major cereals.

Improving Nitrogen Status Estimation in Malting Barley Based on Hyperspectral Reflectance and Artificial Neural Networks

Malting barley requires sensitive methods for N status estimation during the vegetation period, as inadequate N nutrition can significantly limit yield formation, while overfertilization often leads to an increase in grain protein content above the limit for malting barley and also to excessive lodging. We hypothesized that the use of N nutrition index and N uptake combined with red-edge or green reflectance would provide extended linearity and higher accuracy in estimating N status across different years, genotypes, and densities, and the accuracy of N status estimation will be further improved by using artificial neural network based on multiple spectral reflectance wavelengths. Multifactorial field experiments on interactive effects of N nutrition, sowing density, and genotype were conducted in 2011–2013 to develop methods for estimation of N status and to reduce dependency on changing environmental conditions, genotype, or barley management. N nutrition index (NNI) and total N uptake were used to correct the effect of biomass accumulation and N dilution during plant development. We employed an artificial neural network to integrate data from multiple reflectance wavelengths and thereby eliminate the effects of such interfering factors as genotype, sowing density, and year. NNI and N uptake significantly reduced the interannual variation in relationships to vegetation indices documented for N content. The vegetation indices showing the best performance across years were mainly based on red-edge and carotenoid absorption bands. The use of an artificial neural network also significantly improved the estimation of all N status indicators, including N content. The critical reflectance wavelengths for neural network training were in spectral bands 400–490, 530–570, and 710–720 nm. In summary, combining NNI or N uptake and neural network increased the accuracy of N status estimation to up 94%, compared to less than 60% for N concentration.

Durum Wheat Yield and Grain Quality in Early Transition from Conventional to Conservation Tillage in Semi-Arid Mediterranean Conditions

In semi-arid Mediterranean areas, there is a growing interest in adopting conservation tillage practices for their advantages in improving soils fertility, reducing production costs, and stabilizing crop yields. The aim of this study conducted in the 2019 and 2020 seasons was to investigate the effect of three tillage systems—conventional tillage (CT), minimum tillage (MT), and no-tillage (NT)—on grain yield, yield components, and quality indices of a durum wheat crop (Triticum durum Desf. cv. Simeto) grown in monoculture in semi-arid conditions of Northern Algeria. Tillage systems had a significant effect on the average yield of the 2 years, with NT being 28% and 35% higher than CT and MT, respectively—a trend even more evident in the second year under observation. The superiority of NT (p &lt; 0.001) in the second year (2020) is mainly due to the increased spikes density (318.93 spikes m2 under NT vs. 225.07 and 215.20 spikes m2 under MT and CT, respectively). Yield components and quality parameters were more affected by climatic conditions than by tillage treatments. The number of kernels per spike being the most affected by water and heat stresses occurred in 2020 season. A decrease of 51% is noted regardless of the tillage treatment, which negatively affected the grain yield in that year (1.9 vs. 1.3 t ha−1 in 2019 and 2020, respectively). This stress also induced an increase in grain protein content, but a reduction of its weight. The results of this study conducted in the early transition from conventional to conservation tillage show that durum wheat grown under NT results in higher grain yield than the other systems in the specific operative conditions of the study region, providing better seed emergence and better spikes density, especially in the dry years. Moreover, the quality parameters are more affected by weather conditions than by the tillage system—with an interaction year × tillage system significant only for the grain.

Yield and quality of winter wheat (Triticum aestivum L.) grain in relation to nitrogen fertilization

Winter wheat is commonly cultivated in Ukraine. This crop has nutritional requirements that have been affected due to the climate changes that in the recent years the country has been suffered. In the spring season, the plant is found in growing stage, which requires a suitable nitrogen nutrition and it must be supplied due to the deficit of this element during the vegetative development. Within this framework, this study aimed to establish the optimal nitrogen rate for winter wheat that was applied in different configurations on leached black soil, and to determine the effectiveness of nitrogen application to the frozen soil surface in early spring as a basis for these fertilizations. The experiment was conducted at the Bila Tserkva ResearchSelection Station (Ukraine) during 2017–2019. The soil of this place corresponds to a leached loamy black soil (Mollisol) with content of organic matter between 3.6-3.8%, mobile phosphorus (P2O5) 156-166 mg kg-1, potassium (K2O) 64-77 mg kg-1, and pHKCl 5.8–6.3. A randomized experimental design with four nitrogen rates (0, 60, 80, 110 kg ha-1) with four replications as factorial arrangement was used. The results indicated that winter wheat yield was significantly affected by all nitrogen fertilizer rates (P&lt;0.05). The highest average grain yield was obtained with 110 kg ha-1 nitrogen rate that combined application nitrogen to the frozen soil surface and the foliar feeding with 6.90 t ha-1. In years of regular precipitation during the growing season (2018-2019), nitrogen fertilizers had a more pronounced effect on winter wheat yield than in a year of precipitation deficiency (2017). A significant increase in grain protein content was obtained in variants where foliar feeding of winter wheat with urea solution was a part of fertilization strategy; it was attributed to nitrogen rates of 80 and 110 kg ha-1. The increase in protein content of the grain was less dependent on the weather conditions and was stable through the years of experiment.

Assessment of Four Portuguese Wheat Landrace Diversity to Cope With Global Warming.

Wheat is a dietary staple consumed worldwide strongly responsible for proteins and carbohydrate population intake. However, wheat production and quality will scarcely fulfill forward demands, which are compounded by high-temperature (HT) events as heatwaves, increasingly common in Portugal. Thus, landraces assume crucial importance as potential reservoirs of useful traits for wheat breeding and may be pre-adapted to extreme environmental conditions. This work evaluates four Portuguese landrace yield and grain composition through attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy, particularly protein content, and their responses to HT treatment mimicking a heatwave. Landraces showed distinct yield traits, especially plant height and first spike grain number, and a similar pattern in FTIR spectra, although revealing differences in grain components’ proportions. Comparison between spectra band intensity indicates that Ardito has the highest protein-related peaks, contrary to Magueija, which appears to be the landrace with higher lipid content. In plants submitted to 1 week of HT treatment 10 days after anthesis, the first spike grain size and weight were markedly reduced in all landraces. Additionally, it was observed that a general increase in grain protein content in the four landraces, being the increment observed in Ardito and Grécia, is statistically significant. The comparative assessment of control and HT average FTIR spectra denoted also the occurrence of alterations in grain polysaccharide composition. An integrated assessment of the evaluations performed revealed that Ardito and Magueija landraces presented diverse yield-related characteristics and distinct responses to cope with HT. In fact, the former landrace revealed considerable grain yield diminution along with an increase in grain protein proportion after HT, while the latter showed a significant increase in spikes and grain number, with grain quality detriment. These results reinforce the relevance of scrutinizing old genotype diversity seeking for useful characteristics, particularly considering HT impact on grain production and quality.

Yield reduction historically associated with the Aegilops ventricosa 7DV introgression is genetically and physically distinct from the eyespot resistance gene Pch1

Key messageYield penalty and increased grain protein content traits associated with Aegilops ventricosa 7D introgression have been mapped for the first time, and they are physically distinct from the eyespot resistance locus Pch1.Wheat wild relatives represent an important source of genetic variation, but introgression of agronomically relevant genes, such as for disease resistance, may lead to the simultaneous introduction of genetically linked deleterious traits. Pch1 is a dominant gene, conferring resistance to eyespot and was introgressed to wheat from Aegilops ventricosa as part of a large segment of the 7DV chromosome. This introgression has been associated with a significant yield reduction and a concomitant increase in grain protein content. In this study, we evaluated both traits and their relationship to the location of the Pch1 gene. We found that both QTLs were clearly distinct from the Pch1 gene, being located on a different linkage group to Pch1. In addition, we found that the QTL for increased grain protein content was strong and consistent across field trials, whereas the yield penalty QTL was unstable and environmentally dependent. The yield and grain protein content QTLs were genetically linked and located in the same linkage group. This finding is due in part to the small size of the population, and to the restricted recombination between wheat 7D and Ae. ventricosa 7Dv chromosomes. Although recombination in this interval is rare, it does occur. A recombinant line containing Pch1 and 7D_KASP6, the marker associated with increase in grain protein content, but not Xwmc221, the marker associated with the yield penalty effect, was identified.

Introgression of an expressed HMW 1Ay glutenin subunit allele into bread wheat cv. Lincoln increases grain protein content and breadmaking quality without yield penalty.

An expressed HMW glutenin subunit Glu-Ay showed positive impacts on a range of wheat processing quality and yield traits. The grain protein compositions are significantly optimised for baking, resulting in a better breadmaking quality. The unique breadmaking properties of wheat flour are related to the quality and quantity of high-molecular weight glutenin subunits (HMW-GSs) present in the grain. In the current study, the silent 1Ay HMW-GS allele, present in most bread wheat cultivars, was replaced by the expressed 1Ay21* allele, which was introgressed into Australian bread wheat cultivar Lincoln by a backcrossing and selfing scheme. Stability of gene expression and the effect of the introgressed 1Ay21* subunit on protein composition, agronomic traits, flour functionality, and breadmaking quality were studied using BC4F5 grain grown in glasshouse and field. Field phenotyping and grain quality testing showed that the 1Ay21* gene conferred significant improvements to a range of traits, including an increase in grain protein content by up to 9%, UPP% by up to 24%, bread volume by up to 28%. The glasshouse experiment and one of the field trials showed positive 1Ay21* effects on yield, while one field trial showed one significant effects. This indicates that expression of the 1Ay21* gene has the potential of simultaneously increasing protein content and grain yield under certain environment. The qualitative improvements of the grain also led to a reduction of the energy required during the baking process in addition to the significant positive effects on bread quality.

Can nitrogen fertilization be used to modulate yield, protein content and bread-making quality in Uruguayan wheat?

Genotype and environment jointly determine yield and bread-making quality of bread wheat, being possible modulators for these characters. Eleven cultivars were grown at three different nitrogen regimes combining quantity and timing of nitrogen availability for two years; yield, grain protein concentration and Alveograph parameters were determined. Amount and size distribution of proteins were measured using Size Exclusion-High Performance Liquid Chromatography. The results showed year to be the most important determinant of percentage of unextractable polymeric protein in total polymeric protein (%UPP) and yield, while nitrogen regime determined grain protein concentration, the total amount of SDS-extractable and -unextractable proteins, Alveograph W and L. High nitrogen regime generated three types of responses among the cultivars; i) an increase of yield and grain protein concentration, ii) an increase in grain protein concentration but a reduction in %UPP, and iii) an increase in %UPP. For group ii, a low nitrogen regime at early stages but high at later stages was preferential, while for other groups, a high nitrogen regime during the whole season was the most beneficial. This study showed that it is possible to modulate yield and quality in bread wheat by the nitrogen regime, although an understanding of genotype-environmental relationships is necessary.

Tos17 insertion in NADH-dependent glutamate synthase genes leads to an increase in grain protein content in rice

Nutrition from cereal grains sustains human life, and the protein content of rice grains is an important source for humans. Recent forward genetics studies pointed out the significant contribution of NADH-dependent glutamate synthase (NADH-GOGAT) to increased grain protein content in durum wheat. The aim of this work was to investigate the contribution of the two NADH-GOGAT enzymes in rice, NADH-GOGAT1, and NADH-GOGAT2, to rice grain protein content, using a reverse genetics approach. The grain protein content and free amino acid concentration were determined in Tos17 insertion mutants of the structural gene of each protein. We found a significant increase in protein content in the NADH-GOGAT2 mutant and an increase in free amino acid concentration in both the NADH-GOGAT1 and the NADH-GOGAT2 mutants. These results provide the first nutritional characterization of the NADH-GOGAT mutants. Rice containing increased protein and amino acid concentrations may have potential to contribute to improved rice nutrition. Since previous field analysis had indicated a 40% yield reduction in each of the mutants, future work should focus on improving the yield of the mutants.

Response of Barley Plants to Potassium Spraying under Water Deficit Conditions

A field experiment was carried out at the Experimental Farm of Sakha Agricultural Research Station during the winter season of 2014/2015 and 2015/2016 to study the impact of foliar application with potassium on growth, yield, its components and the economic yield as well as on irrigation water productivity of barley Giza 126 cultivar under water deficit conditions. The experiment was laid out in spilt plot design with four replications. The main plots were designated to irrigation treatments i.e. I0 = full irrigation (control), I1 = two irrigations at 35 and 70 days after sowing (DAS), and I2 = one irrigation at 35 days after sowing (DAS), while the sub plots were devoted to four treatments of foliar application with potassium (K0 = without spray, K1 = 1% K2O, K2= 2 % K2O and K3= 3% K2O) in the form of potassium sulfate (48%). Results showed that, increasing water stress significantly retard photosynthetic pigments, flag leaf area, relative water content (RWC %), yield and its components and carbohydrate content. On the other hand, plants under water stress showed marked increase in grain protein content. Foliar spraying with potassium markedly increased most growth and yield parameters and quality of barley grains. The results showed that high irrigation water productivity (IWP) is attainable without significant yield penalty (utilizing a two irrigations at 35 and 70 days after sowing (DAS), or one irrigation after 35 DAS and foliar spraying with potassium (1% K2O, or 2 % K2O, or 3 % K2O) offering chance for improving land level water use and enhancing the crop economic return.

The Effects of Foliar Nitrogen Treatments at Heading Stage on Grain Protein Contents of Bread Wheat Cultivars

The studies were conducted at Transitional Zone Agricultural Research Institute in Eskisehir and Selcuk University in 2008-2010 growing seasons. Two bread wheat cultivars (Gerek 79 and Bezostaja 1) were used as plant material. Experimental treatments were 0, 30, 60, 90 and 120 kg N ha -1 applied at planting and tillering stages (early-season treatments) and 0, 20, 40 and 60 kg N ha -1 (urea form) applied at heading stage (late-season treatments) as foliar applications. A variation was created in terms of SPAD and TN at heading stage through different nitrogen rates in traditional nitrogen application time. Results under rain-fed conditions revealed that foliar nitrogen at heading stage could increase the protein content at least 1%, and the critical threshold NSPAD value was 0.96 for Bezostaja 1 and 0.94 for Gerek 79. On the other hand, the threshold TN value was 4.22% for Bezostaja 1 and 3.75% for Gerek 79 under the same conditions. The increase in grain protein content of Bezostaja 1 per 10 kg ha -1 of N was 2.0% in early-season and 3.2% in late-season treatments. The same increase rates for Gerek 79 were 1.5% in early-season and 2.7% in late-season treatments. Although both early and late-season treatments were effective on protein content and related quality traits, the application of foliar solution in heading stage was more dominant as compared to the traditional nitrogen application time.

Shift of grain protein composition in bread wheat under summer drought events

AbstractClimate change bears the risk of more frequent drought stress in the northern hemisphere with more frequent early summer drought events affecting main grain crops. Winter wheat (Triticum aestivum L.) is susceptible for such drought events at the flowering and grain filling stages. After drought, the grain yield decrease of three hybrids was about 20% lower compared to three wheat lines analyzed. Wheat grain proteins are classified into four main components such as albumin and globulin, gliadin, and glutenin. The latter two are closely related to the baking quality of flour and might be affected by drought. However, detailed knowledge about the influence of drought on the synthesis of specific storage protein fractions is scarce. By analyzing the grain protein fractions by means of SDS‐PAGE technique, we detected an increase in grain protein content as well as in HMW and some LMW glutenin sub‐fractions. The glutenin fraction seems to be most variable in gene expression under different environmental scenarios such as drought. However, the protein yield as well as the grain yield may be strongly decreased, which might be not acceptable in practice.

Metabolite profiling of the response to high-nitrogen fertilizer during grain development of bread wheat (Triticum aestivum L.)

Wheat yield and quality are dependent largely on nitrogen (N) availability. In this study, we performed the first metabolomic analysis of the response to high-N fertilizer during wheat grain development using non-targeted gas chromatography-mass spectrometry (GC–MS). Quality parameter analyses demonstrated that high-N fertilizer application led to a significant increase in grain protein content and improvement in starch and bread-making quality. Comparative metabolomic profiling of six grain developmental stages resulted in identification of 74 metabolites, including amino acids, carbohydrates, organic acids and lipids/alcohol, which are primarily involved in carbon and N metabolism. Under high-N fertilizer treatment, numerous metabolites accumulated significantly during grain development. Principal component analysis revealed two principal components as being responsible for the variances resulting from N-fertilizer treatments. Metabolite–metabolite correlation analysis demonstrated that the high-N treatment group had a greater number of positive correlations among metabolites, suggesting that high-N fertilizer treatment induced a concerted metabolic change that resulted in improved grain development. Particularly, the high-N treatment-mediated significant accumulation of metabolites involved in the TCA cycle, starch and storage protein synthesis could be responsible for the improvement of grain yield and quality. Our results provide new insight into the molecular mechanisms of wheat grain development and yield and quality.