High-yielding Wheat Research Articles

Influence of photothermal quotient in the critical period on yield potential of cereals–A comparison of wheat and barley

ContextResearch in grain crops has focused on understanding the critical period (CP) for yield formation to develop genetic and agronomic options that minimize stress or resource limitation during this time. While the link between the photothermal quotient (PTQ) in the CP and yield potential is known for wheat, it needs re-evaluation with current genetics and agronomy, and is less explored in barley, especially in high productivity areas. ObjectiveOur aim was to determine if a) the PTQ-yield relationship in wheat has evolved with new cultivars and agronomic practices, and b) if barley shares similar CP timing and duration with wheat or requires species-specific adjustments in high production zones. MethodsFrom trials In the Australian high production zones, we compiled a dataset (25 site-years) of high-yielding wheat and barley from carefully managed field experiments. The sites analysed had barley and wheat varying in genetics and management across different photothermal environments and where seasonal water supply exceeded 400 mm, and were not constrained by nutrients, allowing us to evaluate the sensitivity to relationship between radiation and temperature during the CP on yield potential. ResultsWe created a new PTQ-based yield potential frontier for wheat and barley, measuring yield increase per PTQ unit. The best model used PTQ data from 20 days before to 10 days after flowering. In barley, changes in the CP timing and length didn't affect the results as expected. The slope of the relationship was lower for barley, indicating lower yields at higher PTQ compared to wheat, highlighting their physiological differences. ConclusionsOur study shows Australia's wheat and barley yields, over 15 Mg ha−1 in wheat and >12 Mg ha−1 in barley respectively, are more influenced by PTQ during the CP than by seasonal water when water supply estimates exceed 400 mm in Australia. We present a simple, physiologically sound PTQ equation as a yield benchmark for wheat (WPYptq= 10.62PTQ-2.85) and barley (BPYptq= 6.73PTQ+1.65). ImplicationsEfforts in agronomy and breeding should aim at enhancing resource availability and partitioning during the CP and aligning the CP with environmental conditions. The straightforward PTQ model for predicting yield potential in Australia's higher production areas matches complex simulations well, aiding in optimizing production systems and guiding future yield potential research.

Investigating the effects of colchicine on seed germination and morphological traits in durum wheat (Triticum turgidum subs. durum Desf.)

A broader genetic diversity holds great promise for enhancing the productivity of durum wheat, especially under challenging environmental stressors. Establishing an improved genetic pool through the pre-treatment of durum wheat seeds with antimitotic agents, like colchicine, could play a pivotal role in boosting seed germination, seedling growth, morphological characteristics, and overall yield. This study explored the impact of colchicine on seed germination, growth, and morphological traits in two durum wheat cultivars (PDW-233 and DDW-47). For the experiment, presoaked seeds from each cultivar were exposed to different colchicine concentrations (0.1%, 0.2%, and 0.3%) over an 8-hour period. Quantitative traits such as germination percentage, plant survival rate, plant height, tiller number per plant, seeds per spike, and 1000-grain weight were meticulously measured in the treated plants. The results revealed considerable variability in these quantitative traits across the different colchicine treatments in both wheat varieties in the M1 generation. Significant alterations were observed across various concentrations, indicating colchicine’s potential for inducing genetic diversity within a single generation. These findings underscore the effectiveness of colchicine as a mutagenic agent capable of stimulating notable genetic variation, which, with precise selection, can lead to the identification and development of promising high-yield, stress-tolerant mutants in durum wheat. The results of this study suggest that rigorous selection and further breeding of desirable mutants could result in significantly improved and high-yielding durum wheat lines in subsequent generations. Thus, this approach may offer a viable pathway for enhancing durum wheat’s genetic resilience and productivity.

Metabolite profiling in ten bread wheat (Triticum aestivum L.) genotypes in response to drought stress

Wheat is frequently constrained by extreme environmental conditions such as drought. Improving drought tolerance in wheat genotypes is crucial for ensuring food security, especially considering the challenges posed by climate change. To reveal the involvement of metabolites in drought response, ten diverse wheat genotypes were investigated under control and water scarcity conditions. The field experiments were set-up, using a 5 × 2 alpha lattice design, with two replicates per treatment, in the 2022 and 2023 growing seasons. Metabolites associated with drought tolerance were analysed using ultra-high performance liquid chromatography, coupled with a quadruple time of flight mass spectrometry (UHPLC-qTOF-MS). Multivariate statistical analysis (MVDA) tools, viz. principal component analysis (PCA) and the orthogonal projection to latent structures-discriminant analysis (OPLS-DA) loading scatter plot were used to identify the metabolites that are positively and negatively correlated to drought stress. Significant variation (p < 0.05) among genotypes was observed, with 58 metabolites annotated, including phenolic acids, carbohydrates, and fatty acids. The annotated compounds were linked to thirteen most significant pathways, with one carbon metabolism, cutin, suberin and wax synthesis and starch and sucrose metabolism being significantly affected by water stress, based on the KEGG pathway analysis. The two high-yielding wheat genotypes (LM48 and BW140) under drought stress displayed significant upregulation of key metabolites such as sinapoyl hydroxyagmatine, 7-oxostigmasterol, 1-O-caffeoyl-3-O-p-coumaroylglycerol, and 3-beta-3-lupanol, when compared to the non-stressed conditions. This study demonstrates the prospects of applied metabolomics for chemotaxonomic classification, phenotyping and selection in plant breeding, as well as potential use in crop improvement.

Reshaping the field: technocratic facts, high wheat yields, and the making of an ecological disaster

ABSTRACT Today the Yaqui Valley, a renowned farming region in northern Mexico, is a top emitter of greenhouse gas. Made famous as the birthplace of the Green Revolution, the high-yielding seeds that transformed the world’s farming were engineered in the research station located in the valley. Research led by agronomist Norman Borlaug not only transformed seeds but significantly altered the contemporary understanding of fertilizer use. Five times as much fertilizer as had previously been used became part of the needed recipe to produce high yields of wheat. Decades later, soil and groundwater contamination could be traced to the heavy use of agrochemicals. This article examines pre-1970s writings, both scientific publications and an oral history, to understand how this leap in fertilizer use became normalized and persisted for nearly seven decades.

The molecular dialogue between Zymoseptoria tritici and wheat.

Zymoseptoria tritici is a highly damaging pathogen that causes high wheat yield losses in temperate climates. Z. tritici emerged during the domestication of wheat in the Fertile Crescent and has been extensively used as a model system for population genetic and genomic studies. New genetic tools and resources have provided a better understanding of the molecular components involved in the wheat-Z. tritici interaction, highlighted by the cloning of three wheat resistance genes and four Z. tritici avirulence genes. Despite the considerable progress made in the last few years, the mechanisms that mediate Z. tritici colonization remain largely unknown. In this review, we summarize the latest advances in understanding the molecular components mediating wheat-Z. tritici interactions and we discuss future research lines to close current knowledge gaps.

Effects of Deficit Irrigation on Spring Wheat Lignification Process, Yield Productivity and Stalk Strength

Moderate deficit irrigation can improve lignin metabolism, thereby increasing wheat yield and lodging resistance. The moisture-sensitive variety Xinchun 22 (XC22) and drought-resistant variety Xinchun 6 (XC6) were used as experimental materials. We set mild drought (T1, J1 and 60–65% FC, where FC is the field capacity) and moderate drought (T2, J2 and 45–50% FC) during the tillering stage (T) and the jointing stage (J). We used conventional drip irrigation as a control (CK and 75–80% FC). The results show that the activity of lignin synthesis-related enzymes decreased with the growth process, while the accumulation and monomer content of lignin increased under different water treatments. The lignin metabolism and morphological characteristics of XC6 were higher than those of XC22. Under the same processing conditions, the indicators of XC22 showed more significant changes and were more sensitive to changes in the moisture content. Compared with other treatments, the stem thickness and wall thickness of the J1 treatment increased by 0.86–23.49% and 1.72–23.58%. The yield of the T1 treatment was the highest, increasing by 3.05–44.06% compared to other treatments. In addition, by improving PAL, H-type lignin monomers, S-type lignin monomers, stem thickness and lignin metabolism, grain yield can be increased. After mild drought during the jointing stage, J1 significantly improved the lignin metabolism capacity of the stem, increased stem thickness and wall thickness, and was beneficial for improving lodging resistance. The T1 treatment favored the improvement of the production capacity of assimilates, thus promoting a high yield of spring wheat.

A natural variation of TaERF-A1 encoding an AP2/ERF transcription factor confers semidwarf plant architecture and increased lodging resistance in wheat

The introduction of Reduced height (Rht) genes into wheat varieties results in semidwarf plant architecture with largely improved lodging resistance and harvest indices. Therefore, the exploration of new Rht gene resources to breed semidwarf wheat cultivars has been a major strategy for guaranteeing high and stable grain yields of wheat since the 1960s. In this study, we report the map-based cloning of TaERF-A1, which encodes an AP2/ERF transcription factor and acts as a positive regulator of wheat stem elongation, as a new gene for regulating plant height and spike length. The natural variant TaERF-A1JD6, characterized by a substitution from Phe (derived from Nongda3338) to Ser (derived from Jingdong6) at position 178, significantly weakened the stability of the TaERF-A1 protein. As a result, this substitution led to partly attenuated transcriptional activation of TaERF-A1-targeted downstream genes, including TaPIF4, resulting in the restriction of stem and spike elongation. Importantly, introgression of the semidwarfing-related allele TaERF-A1JD6 in wheat materials significantly enhanced lodging resistance, especially in dense cropping systems. Therefore, our study reveals TaERF-A1JD6 as a new Rht gene resource for breeding semidwarf wheat varieties with increased yield stability.

Long-Term Manuring and Fertilization Influence on Soil Properties and Wheat Productivity in Semi-Arid Regions

Information on the long-term effects of the addition of organics and fertilizers to wheat under the pearl millet–wheat cropping system with semi-arid conditions in north-western India is still lacking. The present research was conducted in an ongoing field experiment initiated during Rabi 1995 at the Research Farm of Chaudhary Charan Singh at Haryana Agricultural University, Hisar. After 25 years, the impacts of nutrient management practices on soil fertility and wheat productivity were evaluated. The experiment comprised a total of eight treatment combinations viz. half and full doses of recommended fertilizers (N and P), organic manures (FYM: farmyard manure, POM: poultry manure, and PRM: press mud) alone and in combination with NP fertilizers. The conjoint application of organic manure and chemical fertilizers resulted in a positive influx of nutrients via increasing total organic carbon (TOC), available N, P, K, and S, which ranged from 0.46 to 1.42%, 122.70 to 194.70, 15.66 to 74.92, 340.5 to 761.2, and 15.26 to 54.63 kg ha−1 in surface soil (0–15 cm), respectively. Carbon fractions and crop yield were significantly improved by adopting integrated nutrient management (INM). The TOC showed a positive and significant correlation with C fractions (r &gt; 0.92) and with soil-available N, P, K, and S (r &gt; 0.77) content. The data also revealed a strong relationship between TOC and soil-available (0–15 cm) nutrients i.e., available N (R2= 0.769), available P (R2 = 0.881), available K (R2 = 0.758), and available S (R2 = 0.914), respectively. Thus, practices that increased TOC were also beneficial in enhancing the availability of the nutrients in the soil. A positive and highly significant correlation was also found among wheat yield, nutrient (NPKS) content, and uptake. A polynomial relationship between grain yield and grain N (R2 = 0.962), P (R2 = 0.946), and K (R2 = 0.967) content, and between straw yield and straw N (R2 = 0.830), P (R2 = 0.541) and K (R2 = 0.976) content was obtained. Integrated use of PRM7.5 followed by FYM15 and POM5 coupled with NP fertilizers proved best, which could be beneficial for obtaining nutritious and highest wheat yield (grain: 6.01 t ha−1 and straw: 7.70 t ha−1) coupled with improved fertility within a sustained manner under the pearl millet–wheat sequence in prevailing semi-arid conditions of the North Indian state of Haryana.

Problems and effectiveness of breeding of winter wheat varieties with increased environmental stability

Aim. The search of adaptive response peculiarities to adverse environmental factors is an important condition of development of varietal technologies and control of adaptive potential of winter wheat varieties. Methods. The studies were carried out in accordance with the field test methodology. The wheat varieties of different types of growing, different genetic and ecological origins were studied. Results. The alternative variety Clarisa and the new universal varieties of winter wheat Perlyna, Askaniyska, Askaniyska Bereginya were characterized by the highest yield at different times of spring vegetation recovery. Thus, on average over the years of research, they exceeded the standard variety of Kherson Bezosta by 0.51–1.27 t/ha in terms of yield, and under unfavorable conditions of the late recovery of spring vegetation, their advantage was at the level of 0.58–1.34 t/ha. Conclusions. For stable production of high-yielding winter soft wheat grain, use new varieties of the universal type Askaniyska, Askaniyska Bereginya, Perlyna and alternative types Clarissa, Solomia for different agrophones for late sowing periods according to different predecessors.

Agronomic responses and economic returns from wheat–canola rotation under Humalite and urea applications

AbstractHumalite is a humic acid‐rich biostimulant known for its ability to improve plant agronomic parameters and increase crop nitrogen use. Limited field research exists on Humalite effect, its application rate, and its interaction with urea, especially at reduced rates on grain agronomic parameters. Therefore, a field study was conducted from 2021 to 2023 at three Alberta sites—Battle River Research Group (BRRG), Gateway Research Organization (GRO), and St. Albert Research Station (St. Albert), in a split‐plot design with four replications, three urea levels (i.e., recommended, half‐recommend, and zero urea) combined with five Humalite rates (0, 56 (or 112), 224, 448, and 896 kg ha−1). In 2021, the highest wheat yields were observed at half urea rates plus 224 kg ha−1 at BRRG (35% yield increase), GRO (8.4% yield increase), and St. Albert (33.5% yield increase). In 2022, canola yields were unaffected by Humalite application rates. In 2023, wheat yields from half‐recommended and recommended urea rates plots outperformed zero urea plots across all sites, regardless of Humalite rates. The highest wheat grain protein content values were observed at 224–448 kg ha−1 of Humalite plus half‐recommended or recommended urea rate. Depending on the site, the highest net revenue resulted from half urea rates plus Humalite at application rates between 112 and 448 kg ha−1 in wheat, that is, optimal Humalite rate for increased profitability. Therefore, the incorporation of biostimulants such as Humalite can reduce urea use and contribute to the sustainability of wheat cropping systems.

Evaluation of Alternative Break Crops in Rotation with Bread Wheat (triticum aestivum l.) in South-Eastern Ethiopia

Crop rotation could be a possible intervention to resolve multifaceted problems of monoculture. In recent years, there is a concern about soil depletion caused by intensive farming. In crop rotation legume crops, which capture atmospheric nitrogen and “fix” it into forms available to plants will increase soil fertility. Faba bean (Vicia faba L.), rapeseed (Brassica napus L.), oat (Avena sativum L.) and vicia (Vicia dasycarpa Ten.) forage mixture were considered as a break/precursor crops. The result showed that most profitable cropping sequence was faba bean grown in a 3 year cycle with 2 crops of wheat (Amanuel et al., 1994). Thus, searching for promising and alternative break crops for wheat based rotation could increase productivity and maximize profit. Adaptaion trial around Bekoji showed that sweet lupine seems an option in tolerating acidity where faba bean is found susceptible. Thus, the objectives of this study was to evaluate alternative break crops on yield and yield components of the succeeding wheat and soil fertility maintenance in the rotation scheme. Thus, this study was executed for three consecutive years from 2017- 2019 main cropping seasons at Kulumsa, Bekoji and Asasa Arsi zone, South-Eastern Ethiopia to evaluate advantage of alternative break crops on yield and yield components of the succeeding wheat and its effect on soil fertility maintenance in the rotation scheme. The experiment was laid out in randomized block design with five replications. The treatment include: wheat-sweet lupine-wheat-wheatwheat in year one (2017), sweet lupine-wheat-wheat faba bean-Ethiopian mustard in year two (2018) and wheat-wheat-wheat-wheat-wheat in the third year (2019). These leguminous crops have improved physico-chemical properties of soil. Plant nutrients of soil on which legumes were grown were increased. This improvement of soil properties by leguminous crops has resulted in higher yield of wheat than plots on which wheat was grown after wheat. Although non-significant, the third year Bekoji and Asasa combined analysis of variance revealed that the highest wheat grain yield (4197kg/ha) was obtained at sweet lupine-wheat-wheat followed by wheat-faba bean-wheat (4003kg/ha). However, plant height was significantly (P&lt;0.05) affected by rotational crops effect. The tallest plant height of wheat (105.0cm) was recoded from wheat-Ethioian mustard-wheat treatment. From this study, sweet lupine-wheat-wheat followed by wheat-faba bean-wheat with proper agronomic packages could be forwarded as a temporary recommendation in Asasa, Bokoji and Kulumsa areas and in areas with similar agro ecologies.

Quantitative Trait Loci Mapping of Heading Date in Wheat under Phosphorus Stress Conditions.

Wheat (Triticum aestivum L.) is a crucial cereal crop, contributing around 20% of global caloric intake. However, challenges such as diminishing arable land, water shortages, and climate change threaten wheat production, making yield enhancement crucial for global food security. The heading date (HD) is a critical factor influencing wheat's growth cycle, harvest timing, climate adaptability, and yield. Understanding the genetic determinants of HD is essential for developing high-yield and stable wheat varieties. This study used a doubled haploid (DH) population from a cross between Jinmai 47 and Jinmai 84. QTL analysis of HD was performed under three phosphorus (P) treatments (low, medium, and normal) across six environments, using Wheat15K high-density SNP technology. The study identified 39 QTLs for HD, distributed across ten chromosomes, accounting for 2.39% to 29.52% of the phenotypic variance. Notably, five stable and major QTLs (Qhd.saw-3A.7, Qhd.saw-3A.8, Qhd.saw-3A.9, Qhd.saw-4A.4, and Qhd.saw-4D.3) were consistently detected across varying P conditions. The additive effects of these major QTLs showed that favorable alleles significantly delayed HD. There was a clear trend of increasing HD delay as the number of favorable alleles increased. Among them, Qhd.saw-3A.8, Qhd.saw-3A.9, and Qhd.saw-4D.3 were identified as novel QTLs with no prior reports of HD QTLs/genes in their respective intervals. Candidate gene analysis highlighted seven highly expressed genes related to Ca2+ transport, hormone signaling, glycosylation, and zinc finger proteins, likely involved in HD regulation. This research elucidates the genetic basis of wheat HD under P stress, providing critical insights for breeding high-yield, stable wheat varieties suited to low-P environments.

Straw return under deep tillage increases grain yield in the rice-rotated wheat cropping system

ContextStraw return under rotary tillage has been used for two decades in the rice-rotated wheat cropping system in the lower Yangtze region of China, but it has become prone to reduce wheat emergence and yield in recent years, and alternative tillage methods are required to ensure the high wheat yields. AimsTo determine whether straw return under deep tillage can improve wheat yield and under what mechanisms. We hypothesize that straw return under deep tillage can increase wheat seedling number by reducing rice stubble and straw coverage, and expand the nutrient pool and root system of the plow soil profile to keep post-anthesis viability for increasing wheat yield. MethodsA field study was conducted during two consecutive years and included four treatments: rotary tillage after straw removal (RT); rotary tillage after straw return (RTS); shallow rotary tillage followed by straw mulch (STS) and deep tillage after straw return (DTS). Wheat seedling number, yield, aboveground nutrient uptake, growth period, root characteristics, and soil nutrients were measured. ResultsCompared to RT, seedling number under RTS and STS decreased by 8.3 % and 13.4 %, respectively, while DTS increased by 14.7 %. Wheat yield under RTS and STS decreased by 3.0 % and 7.3 %, respectively, while DTS increased by 8.2 %. The reduction in seedling number under RTS and STS would be partially offset in wheat yield by an increase in effective tiller number per plant and grain weight. Consequently, the variation in wheat yield among treatments was less than the variation in seedling number. Aboveground N and P accumulation in wheat under DTS were higher than the other treatments. Among four treatments, DTS had the highest root distribution and soil N and P contents in the middle and deep soil layers, thus prolonged grain filling duration. Wheat nutrient uptake at maturity and yield were significantly correlated with root weight density and root length density in both middle and deep soil layers. ConclusionsStraw return under deep tillage can increase nutrient supply capacity and root distribution in deep soil while ensuring wheat emergence, enabling better filling of post-anthesis wheat and yield. It is therefore an effective alternative tillage method suitable for the rice-rotated wheat cropping system.

GST Enzyme Content of Wheat Landraces and Comparison with Modern Varieties

The development of high-yielding modern wheat varieties to feed the growing population has had a negative impact on the production of ancestral and landrace crops. The use of modern varieties, which are very deficient in vitamins, minerals, antioxidants, and flavonoids, has caused people to turn to old varieties due to health problems that arise over time. In this study, which aimed to determine the glutathione S-transferase (GST) enzyme activity of registered varieties and landraces, the differences between the protein values and GST enzyme activity values of wheat were found to be statistically significant. When protein values were analysed among wheat varieties, einkorn wheat had the highest value with 15.53 mg/ml, and KUNDURU-1149 had the second highest value with 13.52 mg/ml. The lowest protein values were found in wheat landraces. Lr-4 had the highest GST enzyme activity with 299.7 mmol/min/mg protein and Lr-10 with 265.3 mmol/min/mg protein. A negative and high correlation was found between wheat protein values and GST enzyme activity, and it was determined that landraces were prominent in terms of GST enzyme activity.

Fungicide Protection as an Agrotechnical Treatment Reducing Nitrogen Gap in Winter Wheat—A Case Study

Protection of high-yielding winter wheat (WW) with fungicides increases the productivity of nitrogen (N) present in the soil–crop system during the growing season. As a consequence of the action of fungicides, the nitrogen gap (NG) reduces. This hypothesis was verified on the basis of data from a field experiment conducted with WW during three growing seasons (2013/2014; 2014/2015, 2015/2016) in Poland. The field experiment included two crop protection systems (CP): (i) CP-0—without fungicides and CP-F—with fungicides and (ii) six N doses increased gradually by 40 kg N ha−1 from 0 to 240 kg N ha−1. The grain yield (GY) of WW treated with fungicides was significantly higher than that of the unprotected. The difference in yields between both CP systems was 17.3% on a plot fertilized with 200 kg N ha−1 (9.13 vs. 11.2 t ha−1). The fungicide yield gap increased progressively with Nf doses from 0.76 t ha−1 in the Nf control plot to 2.17 t ha−1 in the fertilized with 200 kg ha−1. The use of fungicides increased the amount of N in grain (Ngr) from 15 kg N ha−1 in the control N plot to 51 kg N ha−1 in the plot with 200 kg N ha−1. The main source of additional N in grain (Ngr) was inorganic N released from the soil (Ng89) during the WW growing season. The maximum Ng89 values were 64.4 and 83.0 kg N ha−1. These values corresponded to Nf doses of 94.4 and 80.8 kg N ha−1. The Ng89 of 70.1 kg N ha−1 conditioned 100-percentage Nf recovery. As a consequence, the prediction reliability of GY and Ngr was highest when Ng89 was used as a predictor. The net increase in the absolute NG size in response to increasing N input was significantly slower and therefore smaller in fungicide-protected than in unprotected WW. It can be concluded that the use of fungicides due to the increase in inorganic N productivity in the soil–crop system reduces the potential threat of N dispersion into the environment. In the light of the results obtained, it should be concluded that the fungicidal protection of crop plants should be treated as a factor significantly reducing the nitrogen gap and, thus, the yield gap.

Coordination of miR319-TaPCF8 with TaSPL14 orchestrates auxin signaling and biosynthesis to regulate plant height in common wheat.

Wheat culms, comprising four to six internodes, are critically involved in determining plant height and lodging resistance, essential factors for field performance and regional adaptability. This study revealed the regulatory function of miR319 in common wheat plant height. Repression of tae-miR319 through short tandem target mimics (STTM) caused an increased plant height, while overexpression (OE) of tae-miR319 had the opposite effect. Overexpressing a miR319-resistant target gene TaPCF8 (rTaPCF8), increased plant height. TaPCF8 acted as a transcription repressor of downstream genes TaIAAs, which interact physically with TaSPL14. The significant differences of indole-3-acetic acid (IAA) contents indicate the involvement of auxin pathway in miR319-mediated plant height regulation. Finally, we identified two TaPCF8 haplotypes in global wheat collections. TaPCF8-5A-Hap2, as per association and evolution examinations, was subjected to strong substantial selection throughout wheat breeding. This haplotype, associated with shorter plant height, aligns with global breeding requirements. Consequently, in high-yield wheat breeding, we proposed a potential molecular marker for marker-assisted selection (MAS). Our findings offer fresh perspectives into the molecular mechanisms that underlie the miR319-TaPCF8 module's regulation of plant height by orchestrating auxin signaling and biosynthesis in wheat.

Effects of drought on photosynthetic induction in leaves of different wheat genotypes under dark-to-light transition

Adjustment of photosynthetic processes to an increase in irradiance constrains the CO2 assimilation and photosynthetic carbon gain compared to that which would be obtained if photosynthesis reached its terminal value instantaneously. Acceleration of photosynthesis induction under field conditions of fluctuating light opens up new perspectives for increasing yields. However, there is little information on response of photosynthetic processes to changes in the light under drought conditions. In a pot experiment, we have studied the peculiarities of response of CO2- and H2O-gas exchange parameters in flag leaves of 3 winter wheat genotypes to a transition from dark to bright light under drought conditions, to reveal the features of drought effect on photosynthetic induction processes. The plants were exposed to a 7-day drought (30% FC) during the flowering stage. After that, the watering of the treated plants was restored to the control level (70% FC), which was maintained until the end of the growing season. Induction curves of CO2 assimilation and transpiration of the flag leaves were recorded after keeping them in the darkness for 30 minutes, then the light was turned on. It was revealed that drought impacts the photosynthetic apparatus by reducing its maximum functional intensity as well as by diminishing its ability to respond to changing light conditions. Specifically, drought slows the rate of gas exchange increase during transitions from dark to light. High-yielding wheat genotypes, which had higher assimilation rates and stomatal conductance under optimal watering, showed increased sensitivity to drought. The reduction in the CO2 assimilation rate in wheat leaves under drought was primarily due to damage to the photosynthetic apparatus in mesophyll cells, rather than inhibition of stomatal conductance. This conclusion is supported by Ci value calculations, which were highest at the lowest CO2 assimilation rate at the beginning of light exposure and lowest at the highest CO2 assimilation rate when reaching a steady-state plateau. The stronger impact of the drought on the biochemical components of the photosynthetic apparatus than on stomata is also suggested by a decrease in instantaneous water use efficiency (WUEi) during photosynthesis. The genotypic differences in the effects of drought on the dynamics of photosynthetic induction parameters during dark-to-light transitions in wheat leaves suggest the potential of these traits for evaluating breeding material. This could enhance the ecological plasticity of new wheat varieties.

Penalties in Granule Size Distribution and Viscosity Parameters of Starch Caused by Lodging in Winter Wheat

Granule size distribution of wheat starch is an important characteristic that could affect the functionality of wheat (Triticum aestivum L.) products. Lodging is a major limiting factor for wheat production. Few studies have been conducted to clarify how lodging influences the granule size distribution and viscosity parameters of starch in wheat grains. Two growing seasons, two high-yield winter wheat cultivars, and five artificial lodging treatments were imposed. The results indicated that lodging significantly reduced the content of starch and increased that of protein. Additionally, lodging caused a marked drop in both starch and protein yields. The relative loss of grain yield, starch yield, harvest index, and protein yield all differed remarkably among lodging treatments with a ranking of L2 &gt; L1 &gt; L4 &gt; L3. Lodging also led to a reduction in the proportion (both by volume and by surface area) of B-type granules and a corresponding increase in that of A-type granules, and the more serious the lodging degree, the greater effect on the changes in these proportions. The smaller starch granules predominated in number, even though their collective contribution to the overall volume is was relatively minor. Meanwhile, it was found that the peak viscosity, hold viscosity, final viscosity, breakdown viscosity, and rebound value of wheat starch were significantly decreased by lodging. Correlation analysis showed that the peak and final viscosities were negatively correlated with volume percentages of A-type starch granules, but were positively correlated with B-type granules. This indicates that B-type granules have higher peak and final viscosities compared with A-type granules in wheat kernels. Lodging can reduce the proportion of B-type starch granules, and thus reduce the peak and the final viscosity in wheat grain.

Yield and quality of different wheat cultivars as influenced by agronomic biofortification of N, K, S and Zn through foliar sprays in North-Western India

Agronomic bio-fortification remains a crucial focus area for enhancing wheat productivity and quality while alleviating environmental pressures. Micronutrient deficiencies, particularly in iron (Fe) and zinc (Zn), persist among the Indian population, especially affecting women. These deficiencies can be effectively addressed through agronomic bio-fortification of wheat grains. To tackle this issue, a comprehensive multilocation (4) field experiment was conducted, incorporating four high-yielding wheat cultivars (HD-3226, HI-1544, DBW-187, and PBW-1-Zn) alongside six foliar fertilizer applications (Control, 2% S, 2% N, 0.5% ZnSO4.7H2O, 1% KCl, and combined treatments) during 2021-22 and 2022-23 utilizing a split-plot design with three replications. Analysis over the years revealed that significant impacts of location and cultivar on yield and its attributes, and Fe, Zn, and protein content of grains. Warmer locations like Hisar exhibited higher yields primarily due to significantly increased earheads/m2 and grains number/m2 compared to other locations. Moreover, Fe content in wheat grains was notably higher in Gurdaspur followed by Hisar, surpassing Ludhiana. Notably, cultivar DBW-187 outperformed others with a 14.75% higher grain yield than the least yielding cultivar, HI-1544. PBW-1-Zn exhibited the highest grain Fe and Zn content among the cultivars studied. The interaction between cultivar and location significantly influenced all yield parameters and grain Fe content. Foliar spray of ZnSO4 (0.5%) during stem elongation and milk stages resulted in significantly higher grain Zn content compared to applications of KCl (1.0%), N (2.0%), and S (2.0%) alone, with an increase of 9.9% over no spray. In conclusion, the selection of appropriate cultivars tailored to specific regions, coupled with strategic agronomic bio-fortification approaches, is imperative for enhancing wheat productivity and grain quality, thereby ensuring nutritional security.

Integrating high-throughput phenotyping and genome-wide association studies for enhanced drought resistance and yield prediction in wheat.

Drought, especially terminal drought, severely limits wheat growth and yield. Understanding the complex mechanisms behind the drought response in wheat is essential for developing drought-resistant varieties. This study aimed to dissect the genetic architecture and high-yielding wheat ideotypes under terminal drought. An automated high-throughput phenotyping platform was used to examine 28 392 image-based digital traits (i-traits) under different drought conditions during the flowering stage of a natural wheat population. Of the i-traits examined, 17 073 were identified as drought-related. A genome-wide association study (GWAS) identified 5320 drought-related significant single-nucleotide polymorphisms (SNPs) and 27 SNP clusters. A notable hotspot region controlling wheat drought tolerance was discovered, in which TaPP2C6 was shown to be an important negative regulator of the drought response. The tapp2c6 knockout lines exhibited enhanced drought resistance without a yield penalty. A haplotype analysis revealed a favored allele of TaPP2C6 that was significantly correlated with drought resistance, affirming its potential value in wheat breeding programs. We developed an advanced prediction model for wheat yield and drought resistance using 24 i-traits analyzed by machine learning. In summary, this study provides comprehensive insights into the high-yielding ideotype and an approach for the rapid breeding of drought-resistant wheat.