Wheat Yield Potential Research Articles

Effect of Various Nitrogen Doses and Plant Growth Regulators on Nutrient Uptake and Productivity of Wheat (Triticum aestivum L)

A field experiment was conducted at Research Farm of Bihar Agricultural University, Sabour, Bhagalpur, Bihar, during season of 2019-20, to find out the effect of optimization of nitrogen doses for high yield potential of wheat with plant growth regulators. The experiment was laid out in randomized block and replicated thrice. The experiment ten treatment of different doses of fertilizer with plant growth regulators chlormequat chloride and tebuconazole applied at 0.2% and 0.1% respectively. Experimental revealed that application of 150% recommended doses of NPK resulted significantly higher available nitrogen (171.82 kg ha-1), available phosphorus (27.01 kg ha-1) and available potassium (192.27 kg ha-1) in soil after the harvest of wheat significantly highest nitrogen, phosphorus and potassium uptake by wheat recorded with 150% RDF of NPK with chlormequat chloride (0.2%) and tebuconazole (0.1%). Significantly highest grain and straw yield recorded with 150% NPK + chlormequat chloride (0.2%) and tebuconazole (0.1%) at par with 100% RDF as compare to other treatments harvest index was recorded 125% RDF of N and chlormequat chloride (0.2%) and tebuconazole (0.1%) and 150% RDF of N and chlormequat chloride (0.2%) and tebuconazole (0.1%). The uptake of key nutrients, nitrogen, phosphorus and potassium followed a similar pattern, with 150% recommended doses of NPK along chlormequat chloride (0.2%) and tebuconazole (0.1%). optimal NPK application resulted in positive nutrient balance in the soil. This investigation that managing nutrient with growth regulator in wheat is an economically viable and ecologically sound approach to improve both crop production and soil health through balanced nutrition.

Natural alleles of LEAFY and WAPO1 interact to regulate spikelet number per spike in wheat

Key messageSpecific combinations ofLFY andWAPO1 natural alleles maximize spikelet number per spike in wheat. Spikelet number per spike (SNS) is an important yield component in wheat that determines the maximum number of grains that can be formed in a wheat spike. In wheat, loss-of-function mutations in LEAFY (LFY) or its interacting protein WHEAT ORTHOLOG OF APO1 (WAPO1) significantly reduce SNS by reducing the rate of formation of spikelet meristems. In previous studies, we identified a natural amino acid change in WAPO1 (C47F) that significantly increases SNS in hexaploid wheat. In this study, we searched for natural variants in LFY that were associated with differences in SNS and detected significant effects in the LFY-B region in a nested association mapping population. We generated a large mapping population and confirmed that the LFY-B polymorphism R80S is linked with the differences in SNS, suggesting that LFY-B is the likely causal gene. A haplotype analysis revealed two amino acid changes P34L and R80S, which were both enriched during wheat domestication and breeding suggesting positive selection. We also explored the interactions between the LFY and WAPO1 natural variants for SNS using biparental populations and identified significant interaction, in which the positive effect of the 80S and 34L alleles from LFY-B was only detected in the WAPO-A1 47F background but not in the 47C background. Based on these results, we propose that the allele combination WAPO-A1-47F/LFY-B 34L 80S can be used in wheat breeding programs to maximize SNS and increase grain yield potential in wheat.

Effects of multiple microplastic types on growth of winter wheat and soil properties vary in different agricultural soils

Societal Impact StatementWinter wheat is one of the most important crops in the world. Microplastics, as an emerging pollutant, are widespread in agricultural soils due to various modern agricultural practices and can have adverse impacts on agricultural soils and plant growth. Herein, we investigated the effects of 10 types of microplastics on the properties of three agricultural soil types and the growth of winter wheat. This study contributes insights toward the conservation of agricultural soils and potential wheat yield responses to microplastic. Understanding the mechanisms that underpin the differences in responses to this pollutant class is of great importance for management recommendations.Summary Microplastics (MPs) (size < 5 mm) are increasingly recognized as anthropogenic contaminants that severely affect terrestrial ecosystems. These particles are always detected as a mixture of various polymer types and shapes. However, we have limited knowledge of the effect of combined MPs on plant–soil systems. To address this, we selected 10 types of MP, applied to three soil types singly and in combination along an increasing gradient of 1, 2, 5, 8, and 10 MP types at a content of 0.4% (w/v). After 8 weeks of pre‐incubation, winter wheat (TOBAK) was grown in each pot for another 8 weeks. Shoot and root biomass, soil aggregation, and carbon and nitrogen content were measured. The effects of the same MP on both soil and plant properties were drastically different (in size and effect direction) in the different soil types. However, no clear patterns were observed along an increasing number of microplastic types, suggesting that knowing the number of microplastic types in a sample, at equity of overall concentration, does not help predict effects. In contrast, our findings reveal the complex effects of multiple MPs on the soil–plant system and highlight that soil properties need to be taken into consideration when studying MP effects on terrestrial systems.

Engineering a One Health Super Wheat.

Wheat is the predominant crop worldwide, contributing approximately 20% of protein and calories to the human diet. However, the yield potential of wheat faces limitations due to pests, diseases, and abiotic stresses. Although conventional breeding has improved desirable traits, the use of modern transgenesis technologies has been limited in wheat in comparison to other crops such as maize and soybean. Recent advances in wheat gene cloning and transformation technology now enable the development of a super wheat consistent with the One Health goals of sustainability, food security, and environmental stewardship. This variety combines traits to enhance pest and disease resistance, elevate grain nutritional value, and improve resilience to climate change. In this review, we explore ways to leverage current technologies to combine and transform useful traits into wheat. We also address the requirements of breeders and legal considerations such as patents and regulatory issues.

Productivity, nutrient uptake and nitrogen economy of wheat (Triticum aestivum) in a conservation agriculture-based cotton (Gossypium herbaceum)–wheat system

Conservation agriculture (CA) practices like zero-till and residue retention along with nitrogen management is vital for improving degraded soil health and optimizing the yield potential of wheat (Triticum aestivum L.) crop. Present study was carried out during winter (rabi) seasons of 2021–22 and 2022–23 at ICAR-Indian Agricultural Research Institute, New Delhi for optimizing wheat productivity in a conservation agriculture-based cotton (Gossypium herbaceum L.)-wheat system. The experiment was laid out in a randomized complete block design (RCBD) with three replications consisting of combination of 3 different crop establishment methods, viz. permanent broad bed (PBB), permanent narrow bed (PNB) and zero-till flatbed (ZTFB) with residue (R) and without residue along with 2 doses of nitrogen (75N, 100N) and conventional tillage (CT). The CA-based practices showed overall superior response in terms of growth, yield and nutrients uptake of wheat than CT. Among them, the PBBR100N resulted in significantly higher plant height, leaf area index, dry-matter accumulation, crop growth rate, and relative growth rate compared to PNB, PBB, ZTFB and CT. This treatment led to significantly higher grain (16.2–19.4%) and straw (9.6–11.6%) yields than CT. The net returns and benefit cost ratio (23.4% and 27.9%) were also higher than that in CT. Again, in this treatment, N uptake by wheat crop was higher by 85%, P uptake by 53.1%, and K uptake by 40.1%, and available soil N, P and K by 16.1, 25.3 and 43.7%, respectively than CT. Therefore, the study suggests that the adoption of CA-based practices with broad bed in Indo-Gangetic Plains will not only enhance the productivity of wheat but also result in improved soil health by restoring soil fertility.

Identifying genomic regions associated with key agro‐morphological traits in soft red winter wheat using genome‐wide association study

AbstractAgro‐morphological traits play a significant role in the adaptation of wheat to diverse agroecosystems. Genetic understanding of these traits is crucial to develop cultivars adapted to specific environments and maximize their productivity. This is a comprehensive genome‐wide association study (GWAS) of 230 diverse lines of soft red winter wheat for identifying quantitative trait loci (QTLs) related to eight key agro‐morphological traits. The diversity panel was evaluated in two locations for three consecutive years (2020–2023). A total of 150 significant marker–trait associations were detected, including 65 for three flag leaf traits, 35 for peduncle length, 33 for plant height, 16 for heading date, and one for plant vigor using 27,466 single nucleotide polymorphism (SNP) markers. Eleven high‐confidence major‐effect QTLs explaining greater than 10% phenotypic variance were detected, of which seven were stable, and one showed an association with plant height and peduncle length. QTLs possibly allelic for important dwarfing (Rht23) and vernalization (Vrn‐B1) genes were identified. Six QTLs, QFlw.uga‐1A, QPdl.uga‐1A, QFlw.uga‐2B.2, QPdl.uga‐5A, QPdl.uga‐7A, and QPht.uga‐7B, are presumed to be novel, and nearby candidate gene(s) were identified for all except QPdl.uga‐1A. The pyramiding of favorable alleles from major‐effect QTLs was found to have significant improvement in peduncle length (shortened by 5 cm), flag leaf width (increased by 0.18 cm), and plant height (shortened by 11 cm). This study has improved our genetic understanding of important agro‐morphological traits. These results, upon further validation, can be used in breeding for desirable plant architecture to improve wheat yield potential.

Natural variant of Rht27, a dwarfing gene, enhances yield potential in wheat.

Discovery of Rht27, a dwarf gene in wheat, showed potential in enhancing grain yield by reducing plant height. Plant height plays a crucial role in crop architecture and grain yield, and semi-dwarf Reduced Height (Rht) alleles contribute to lodging resistance and were important in "Green Revolution." However, the use of these alleles is associated with some negative side effects in some environments, such as reduced coleoptile length, low nitrogen use efficiency, and reduced yield. Therefore, novel dwarf gene resources are needed to pave an alternative route to overcome these side effects. In this study, a super-dwarf mutant rht27 was obtained by the mutagenesis of G1812 (Triticum urartu, the progenitor of the A sub-genome of common wheat). Genetic analysis revealed that the dwarf phenotype was regulated by a single recessive genetic factor. The candidate region for Rht27 was narrowed to a 1.55Mb region on chromosome 3, within which we found two potential candidate genes that showed polymorphisms between the mutant and non-mutagenized G1812. Furthermore, the natural variants and elite haplotypes of the two candidates were investigated in a natural population of common wheat. The results showed that the natural variants affect grain yield components, and the dwarf haplotypes show the potential in improving agronomic traits and grain yield. Although the mutation in Rht27 results in severe dwarf phenotype in T. urartu, the natural variants in common wheat showed desirable phenotype, which suggests that Rht27 has the potential to improve wheat yield by utilizing its weak allelic mutation or fine-tuning its expression level.

Characterization of a wheat stable QTL for spike length and its genetic effects on yield-related traits

Spike length (SL) is one of the most important agronomic traits affecting yield potential and stability in wheat. In this study, a major stable quantitative trait locus (QTL) for SL, i.e., qSl-2B, was detected in multiple environments in a recombinant inbred line (RIL) mapping population, KJ-RILs, derived from a cross between Kenong 9204 (KN9204) and Jing 411 (J411). The qSl-2B QTL was mapped to the 60.06–73.06 Mb region on chromosome 2B and could be identified in multiple mapping populations. An InDel molecular marker in the target region was developed based on a sequence analysis of the two parents. To further clarify the breeding use potential of qSl-2B, we analyzed its genetic effects and breeding selection effect using both the KJ-RIL population and a natural mapping population, which consisted of 316 breeding varieties/advanced lines. The results showed that the qSl-2B alleles from KN9204 showed inconsistent genetic effects on SL in the two mapping populations. Moreover, in the KJ-RILs population, the additive effects analysis of qSl-2B showed that additive effect was higher when both qSl-2D and qSl-5A harbor negative alleles under LN and HN. In China, a moderate selection utilization rate for qSl-2B was found in the Huanghuai winter wheat area and the selective utilization rate for qSl-2B continues to increase. The above findings provided a foundation for the genetic improvement of wheat SL in the future via molecular breeding strategies.

Weather based thumb rule models for formulating the crop insurance schemes for wheat in Punjab

<p>Weather based crop insurance schemes play an important role in helping the farmers recovering their financial losses incurred due to aberrant meteorological parameters. Wheat is a major winter season crop grown in Punjab state. To formulate the weather based “weekly and monthly thumb rule models” for predicting the high yield of wheat, a study with meteorological and crop data (2007–2008 to 2021–2022) was conducted for three major wheat growing locations in the state. The results revealed that ideally the monthly maximum/minimum temperatures/rainfall/sunshine duration during the months of December, January, February and March in the range of 20–23 ℃/5–9 ℃/0–38 mm/5–8 h, 17–20 ℃/3–8 ℃/2–57 mm/4–6 h, 19–25 ℃/5–11 ℃/0–79 mm/5–8 h and 25–30 ℃/10–15 ℃/0–56 mm/8–9 h, respectively are optimum for high yield of wheat. The ideally humid (maximum/minimum relative humidity between 90%–97%/36%–63%) weather from November to February is favourable for optimum growth and development of wheat crop. Similarly, the maximum/minimum temperatures/rainfall/sunshine duration for anthesis and grain filling stage in the range of 14–23 ℃/3–10 ℃/0–55 mm/2–9 h and 18–30 ℃/5–15 ℃/0–26 mm/4–10 h are favourable for high yield of wheat crop. The maximum temperature of >18 ℃ during grain filling stage is optimum for potential yield of wheat. While the abiotic stresses like heavy rainfall, heat stress during grain filling stage are not favourable for the productivity of the crop. So, these critical limits of weather parameters are the basis for providing the weather based insurance to the farmers of the region.<strong></strong></p>

Quantitative trait loci detection for three tiller-related traits and the effects on wheat (Triticum aestivum L.) yields.

A total of 38 putative additive QTLs and 55 pairwise putative epistatic QTLs for tiller-related traits were reported, and the candidate genes underlying qMtn-KJ-5D, a novel major and stable QTL for maximum tiller number, were characterized. Tiller-related traits play an important role in determining the yield potential of wheat. Therefore, it is important to elucidate the genetic basis for tiller number when attempting to use genetic improvement as a tool for enhancing wheat yields. In this study, a quantitative trait locus (QTL) analysis of three tiller-related traits was performed on the recombinant inbred lines (RILs) of a mapping population, referred to as KJ-RILs, that was derived from a cross between the Kenong 9204 (KN9204) and Jing 411 (J411) lines. A total of 38 putative additive QTLs and 55 pairwise putative epistatic QTLs for spike number per plant (SNPP), maximum tiller number (MTN), and ear-bearing tiller rate (EBTR) were detected in eight different environments. Among these QTLs with additive effects, three major and stable QTLs were first documented herein. Almost all but two pairwise epistatic QTLs showed minor interaction effects accounting for no more than 3.0% of the phenotypic variance. The genetic effects of two colocated major and stable QTLs, i.e., qSnpp-KJ-5D.1 and qMtn-KJ-5D, for yield-related traits were characterized. The breeding selection effect of the beneficial allele for the two QTLs was characterized, and its genetic effects on yield-related traits were evaluated. The candidate genes underlying qMtn-KJ-5D were predicted based on multi-omics data, and TraesKN5D01HG00080 was identified as a likely candidate gene. Overall, our results will help elucidate the genetic architecture of tiller-related traits and can be used to develop novel wheat varieties with high yields.

DNA Identifications for Wheat Improvement: Targeting Disease Resistance, Quality Traits, and Yield Potential

The pursuit of enhancing wheat cultivars to meet the challenges of evolving pathogens, quality demands, and yield optimization necessitates a profound understanding of the underlying genetic architecture. This review delves into recent advancements in DNA identification techniques and their pivotal role in elucidating key genetic markers associated with disease resistance, quality attributes, and yield potential in wheat. By integrating genomic tools with traditional breeding methods, researchers have made significant strides in pinpointing genomic regions linked to resistance against major pathogens, including rusts, powdery mildew, and Fusarium head blight. Moreover, the identification of genetic markers governing traits such as grain protein content, dough strength, and micronutrient composition has provided breeders with precise targets for improving wheat quality. Furthermore, the exploration of genomic regions associated with yield-related traits, such as biomass accumulation, flowering time, and stress tolerance, holds promise for enhancing wheat productivity under diverse environmental conditions. This synthesis underscores the importance of leveraging DNA identification strategies to expedite the development of resilient, high-quality, and high-yielding wheat varieties, thus contributing to global food security and sustainability in agriculture.

EXPLORING THE RELATIONSHIP BETWEEN PLANT HEIGHT AND YIELD-CONTRIBUTING ATTRIBUTES OF WHEAT IN DROUGHT CONDITIONS

Plant height is the most dynamic yield-affecting trait which has strong genetic and phenological associations with yield performance in wheat. The objective of the study was to explore the effect of plant height on spike yield by investigating the interrelationship between height and yield components of ninety wheat genotypes under a drought environment. Different statistical procedures including correlation, regression, path coefficient, principle component, biplot, and cluster analysis were performed to dissect the associative role of height and yield components in setting the yield potential of wheat plants. High positive correlation and direct effects are seen for spike yield from seed weight (r = 0.73) and seed number (r = 0.60) with a participatory contribution of 58% and 40%, respectively. But plant height is negatively associated with thousand seed weight (-0.22*) and spike yield (-0.15) in such a way that each additional unit (1cm) of height reduces 0.11 g thousand seed weight and 0.06 g spike yield due to negative regression. PC1 and PC2 associate height and yield components respectively and both types of traits moderately oppose each other for simultaneous improvement. Highly tall and short plants were observed with low yield potential under water-limited resources due to strong negative effects either on seed weight or number. An increase in height favors seed number but reduces enough seed weight to cause comparative losses. Intelligent allocation of plant resources to height or spike defines the plant yield potential. Plants with moderate height ranging from 74-83 cm were seen with the best yield potential among five different classes of height. Genotypes HM729, HM829, and HM644 belonged to this class and their better yield potential was due to the balance ratio of seed weight and number. This work would help direct our breeding programs for the improvement of the height-oriented yield potential of wheat.

A chromosome arm from Thinopyrum intermedium × Thinopyrum ponticum hybrid confers increased tillering and yield potential in wheat

Tiller number is a key component of wheat plant architecture having a direct impact on grain yield. Because of their viability, biotic resistance, and abiotic stress tolerance, wild relative species are a valuable gene source for increasing wheat genetic diversity, including yield potential. Agropyron glael, a perennial hybrid of Thinopyrum intermedium and Th. ponticum, was created in the 1930s. Recent genome analyses identified five evolutionarily distinct subgenomes (J, Jst, Jvs, Jr, and St), making A. glael an important gene source for transferring useful agronomical traits into wheat. During a bread wheat × A. glael crossing program, a genetically stable translocation line, WT153397, was developed. Sequential in situ hybridizations (McGISH) with J-, St-, and D-genomic DNA probes and pSc119.2, Afa family, pTa71, and (GAA)7 DNA repeats, as well as molecular markers specific for the wheat 6D chromosome, revealed the presence of a 6DS.6Jvs Robertsonian translocation in the genetic line. Field trials in low-input and high-input breeding nurseries over four growing seasons demonstrated the Agropyron chromosome arm’s high compensating ability for the missing 6DL, as spike morphology and fertility of WT153397 did not differ significantly from those of wheat parents, Mv9kr1 and ‘Mv Karizma.’ Moreover, the introgressed 6Jvs chromosome arm significantly increased the number of productive tillers, resulting in a significantly higher grain yield potential compared to the parental wheat cultivars. The translocated chromosome could be highly purified by flow cytometric sorting due to the intense fluorescent labeling of (GAA)7 clusters on the Thinopyrum chromosome arm, providing an opportunity to use chromosome genomics to identify Agropyron gene variant(s) responsible for the tillering capacity. The translocation line WT153397 is an important genetic stock for functional genetic studies of tiller formation and useful breeding material for increasing wheat yield potential. The study also discusses the use of the translocation line in wheat breeding.

Historic winter wheat yield, production, and economic value trends in Kansas, the “Wheat State”

AbstractYear‐to‐year weather variability and technologies (fertilizer, irrigation, herbicides, conservation tillage, varieties, mechanization, and others) are among factors that affect winter wheat (Triticum aestivum L.) yields in water‐limited cropping systems. The objective of these analyses was to quantify winter wheat yield trends, variability, relationship with weather, yield gap, and value in the “Wheat State,” Kansas. Two data sources were used for this study, that is, annual winter wheat yield reported for selected counties from the United States Department of Agriculture and the Kansas State University wheat variety performance trial near Colby, Garden City, Hays, and Tribune, Kansas. Results of the study showed a decline in harvest area and inflation‐adjusted market value per area of winter wheat beginning in the 1930s. However, both the survey and research data showed continuous increase in winter wheat yield at rates of 3–180 kg ha−1 year−1 that varied by irrigation, location, data source, or time range considered, except for a few years where yield stagnated or declined. Despite increased productivity, results indicated an increase in annual winter wheat yield variation over time. A positive correlation was observed between nonirrigated wheat yield and all months of precipitation except for January, February, and June. October through December precipitation provided the best positive correlation with nonirrigated wheat yield. Wheat yields were negatively correlated with high temperature in months that coincided with wheat flowering and maturity. The yield gap between actual and potential wheat yield was estimated at 15%–55%. The decreasing revenue per land area may be one of the reasons for decreasing wheat planted acreage over time. We concluded producers need to increase adoption of latest technology (varieties with drought and heat tolerance) and management to obtain yield potential. Research should investigate methods to increase the stability of state‐wide wheat production and financial return.

Identification of stable QTLs and candidate genes associated with plant height and spike length in common wheat

Context Plant height and spike length are important traits with significant impact on the potential yield of wheat. It is essential to dissect their genetic control in order to improve yield potential through breeding. Aims We aimed to identify genomic regions with stable and major-effect quantitative trail loci (QTLs) associated with plant height and spike length in common wheat (Triticum aestivum L.). Methods Three recombinant inbred line (RIL) mapping populations were created by crossing a common parental line, Roshan, with three different cultivars: Sabalan, Falat, and Superhead. The RILs were grown over 3 years at five locations under water-stressed and well-watered conditions. Plant height and spike length were measured during each experiment, and inclusive composite interval mapping was used to analyse the data in both single-and multi-environment analyses. Key results Single-environment analysis detected 32 additive QTLs in the three populations. Three novel, stable and non-epistatic QTLs were identified: qPH1D for plant height in the Sabalan background; and qSL1D and qSL1B.3 for spike length in the Falat and Superhead backgrounds, respectively. Between the flanking markers on chromosomes 1B, 1D and 4B, 191 genes were predicted, 20 of which were identified as potential candidates with roles in wheat plant height and spike-related traits. Conclusions The study identified stable QTLs for plant height and spike length in wheat, providing valuable markers for future breeding programs and enhancing yield potential. Implications These results lay a good foundation for fine mapping of QTLs/genes for molecular marker-assisted breeding in wheat in the future.

Rht12b, a widely used ancient allele of TaGA2oxA13, reduces plant height and enhances yield potential in wheat.

We identified a new wheat dwarfing allele Rht12b conferring reduced height and higher grain yield, pinpointed its causal variations, developed a breeding-applicable marker, and traced its origin and worldwide distribution. Plant height control is essential to optimize lodging resistance and yield gain in crops. RHT12 is a reduced height (Rht) locus that is identified in a mutationally induced dwarfing mutant and encodes a gibberellin 2-oxidase TaGA2oxA13. However, the artificial dwarfing allele is not used in wheat breeding due to excessive height reduction. Here, we confirmed a stable Rht locus, overlapping with RHT12, in a panel of wheat cultivars and its dwarfing allele reduced plant height by 5.4-8.2cm, equivalent to Rht12b, a new allele of RHT12. We validated the effect of Rht12b on plant height in a bi-parent mapping population. Importantly, wheat cultivars carrying Rht12b had higher grain yield than those with the contrasting Rht12a allele. Rht12b conferred higher expression level of TaGA2oxA13. Transient activation assays defined SNP-390(C/A) in the promoter of TaGA2oxA13 as the causal variation. An efficient kompetitive allele-specific PCR marker was developed to diagnose Rht12b. Conjoint analysis showed that Rht12b plus the widely used Rht-D1b, Rht8 and Rht24b was the predominant Rht combination and conferred a moderate plant height in tested wheat cultivars. Evolutionary tracking uncovered that RHT12 locus arose from a tandem duplication event with Rht12b firstly appearing in wild emmer. The frequency of Rht12b was approximately 70% (700/1005) in a worldwide wheat panel and comparable to or higher than those of other widely used Rht genes, suggesting it had been subjected to positive selection. These findings not only identify a valuable Rht gene for wheat improvement but also develop a functionally diagnostic tool for marker-assisted breeding.

Associations between endogenous spike cytokinins and grain-number traits in spring wheat genotypes

Genetic variation in grain number has been positively associated with levels of cytokinins in inflorescences in cereals, although studies quantifying endogenous levels in the field are currently lacking. The present study, using a spring wheat association mapping panel (HiBAP II) of 150 lines, quantified associations between spike hormone levels and grain number and associated traits. The HiBAP II panel was grown in the field in NW Mexico under irrigated conditions for one year and a subset of ten genotypes in the glasshouse under well-watered conditions for three years. The spike levels of four cytokinins (trans-zeatin riboside, trans-zeatin, isopentenyladenosine, and isopentenyladenine) were measured by using ultra-high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry. In the glasshouse experiments, spike hormone levels were measured at booting and anthesis, and in the field experiment at anthesis. In the glasshouse experiments, cytokinin levels were also measured in the basal, central, and apical spikelets separately in addition to at the whole spike level. The spike cytokinin levels did not differ significantly between the basal, central and apical sections of the spike. or show a spike position × genotype interaction. In the glasshouse experiments, significant genetic variation was detected for the expression of the four cytokinins in spikes at booting. At booting, spike trans-zeatin concentration ranged amongst genotypes from 4.5 to 16.0 ng g−1 FW and was positively correlated with grain number per main shoot (r = 0.77, P < 0.05). In the field at anthesis, the spike levels of each of trans-zeatin, trans-zeatin riboside and isopentenyl adenosine were positively correlated with grains per m2 (r = 0.17–0.19, P < 0.05). Our results indicated that selection for high spike cytokinin levels in wheat germplasm offers scope to raise grain number and yield potential in wheat.

Integrating APSIM model with machine learning to predict wheat yield spatial distribution

AbstractTraditional simulation models are often point based; thus, more research is needed to emphasize spatial simulation, providing decision‐makers with fast recommendations. Combining machine learning algorithms with spatial process‐based models could be considered an appropriate solution. We created a spatial model in R (APSIMx_R) to generate fine‐resolution data from coarse‐resolution data, which is typically available at the regional level. The APSIM crop model outputs were then deployed to train and test the artificial neural network, creating a hybrid modeling approach for robust spatial simulations. The APSIMx_R package facilitates preparing the required model inputs, executes the prediction, processes, and analyzes the APSIM crop model outputs. This note demonstrates the use of a new approach for creating reproducible crop modeling workflows with the spatial APSIM next‐generation model and machine learning algorithms. The tool was deployed for spatial and temporal simulation of potential wheat yield under different nitrogen rates and various wheat cultivars. The spatial APSIMx_R was validated by comparing the simulated yield at 100 kg N ha−1 to the analogues' actual yield at the same grid points, which showed good agreement (d = 0.89) between the spatially predicted and actual yield. The hybrid approach increased such precision, resulting in higher agreement (d = 0.95) with actual yield. When the interaction between cultivars and nitrogen levels was considered, it was found that the novel cultivar Sakha95 is nitrogen voracious, exhibiting a larger drop in yield (65%) under minimal nitrogen treatment (0 kg N ha−1) relative to the potential yield.

Nutrient management: as a panacea to improve the caryopsis quality and yield potential of durum wheat (Triticum turgidum L.) under the changing climatic conditions.

The increasing human population and the changing climate, which have given rise to frequent drought spells, pose a serious threat to global food security, while identification of high-yielding drought-tolerant genotypes coupled with nutrient management remains a proficient approach to cope with these challenges. An increase in seasonal temperature, recurring drought stress, and elevated atmospheric CO2 are alarmingly affecting durum wheat production, productivity, grain quality, and the human systems it supports. An increase in atmospheric carbon dioxide can improve wheat grain yield in a certain amount, but the right amount of nutrients, water, and other required conditions should be met to realize this benefit. Nutrients including nitrogen, silicon, and sulfur supply could alleviate the adverse effects of abiotic stress by enhancing antioxidant defense and improving nitrogen assimilation, although the effects on plant tolerance to drought stress varied with nitrogen ionic forms. The application of sewage sludge to durum wheat also positively impacts its drought stress tolerance by triggering high accumulation of osmoregulators, improving water retention capacity in the soil, and promoting root growth. These beneficial effect of nutrients contribute to durum wheat ability to withstand and recover from abiotic stress conditions, ultimately enhance its productivity and resilience. While these nutrients can provide benefits when applied in appropriate amounts, their excessive use can lead to adverse environmental consequences. Advanced technologies such as precision nutrient management, unmanned aerial vehicle-based spraying, and anaerobic digestion play significant roles in reducing the negative effects associated with nutrients like sewage sludge, zinc, nanoparticles and silicon fertilizers. Hence, nutrient management practices offer significant potential to enhance the caryopsis quality and yield potential of durum wheat. Through implementing tailored nutrient management strategies, farmers, breeders, and agronomists can contribute to sustainable durum wheat production, ensuring food security and maintaining the economic viability of the crop under the changing climatic conditions.

Maximizing winter wheat yield through planting date and seeding rate management

AbstractPlanting date and seeding rate are two of the most basic and important factors in determining yield potential in winter wheat (Triticum aestivum L.) due to their impact on stand establishment. Timely planting of winter wheat (within a few days after the Hessian fly free date) ensures sufficient time for fall growth and tillering, which are critical for maximizing yield, while adequate seeding rate is necessary to optimize the number of heads per unit area. Field experiments were conducted in Mason, MI during three growing seasons (2020–2022) utilizing five planting dates, ranging from mid‐September to mid‐November, and five seeding rates ranging from 0.8 to 2.4 million seeds acre−1. There was no interaction between planting date and seeding rate in determining yield. Yields declined by 22–48% from the earliest to the latest planting dates in response to a 33–47% reduction in the number of heads acre−1. Seeding rate did not significantly impact yield except at low seeding rates under delayed planting. Maximum yield was achieved with a seeding rate of 0.93, 1.37, 1.47, 1.54, and 1.85 million seeds acre−1 during the mid‐September, late September, mid‐October, late October, and mid‐November plantings, respectively. Overall, results demonstrated that timely planting of wheat is critical for maximizing yield, with significant yield reductions occurring when planting is delayed, regardless of the seeding rate used. Furthermore, while low seeding rates may be used within the optimal planting window without yield penalty, seeding rates should be progressively increased as planting is delayed to diminish yield loss.