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Summary: Seminal roots play a critical role in water and nutrient absorption, particularly in the early developmental stages of wheat. However, the genes responsible for controlling SRN in wheat remain largely unknown.Genetic mapping and functional analyses identified a candidate gene (TraesCS3D01G137200, TaSRN‐3D) encoding a Ser/Thr kinase glycogen synthase kinase 3 (STKc_GSK3) that regulated SRN in wheat. Additionally, experiments involving hormone treatment, nitrate absorption and protein interaction were conducted to explore the regulatory mechanism of TaSRN‐3D.Results showed that the TaSRN‐3D4332 allele inhibited seminal roots initiation and development, while loss‐of‐function mutants showed significantly higher seminal root number (SRN). Exogenous application of epi‐brassinolide could increase the SRN in a HS2‐allelic background. Furthermore, chlorate sensitivity and 15N uptake assays revealed that a higher number of seminal roots promoted nitrate accumulation. TaBSR1 (BIN2‐related SRN Regulator 1, orthologous to OsGRF4/GL2 in rice) acts as an interactor of TaSRN‐3D and promotes TaBSR1 degradation to reduce SRN.This study provides valuable insights into understanding the genetic basis and regulatory network of SRN in wheat, highlighting their roles as potential targets for root‐based improvement in wheat breeding. [ABSTRACT FROM AUTHOR]

SUMMARY: Pre‐harvest sprouting (PHS) is a significant threat to global food security due to its association with losses in both yield and quality. Among the genes involved in PHS resistance in wheat, PHS‐3D (TaMyb10‐D) plays a crucial role. Here, we characterized the sequence variations of TaMyb10 genes in 416 bread wheat and 302 Aegilops tauschii accessions. Within TaMyb10‐A sequences, we identified a deletion ranging from 214 to 305 bp in the signal and amino acid coding region, present in 61.3% of the accessions. Similarly, 79.3% of the TaMyb10‐B sequences within the third exon region exhibited a 19 bp deletion. Additionally, 40.8% of the accessions lacked the 2.4 Mb fragment (in/del mutations) on Chr3D, where TaMyb10‐D/PHS‐3D was located. Interestingly, the geographical distribution of accessions showed little correlation with the divergence of TaMyb10. TaMyb10‐A‐IIIDele, TaMyb10‐B‐IVDele, and TaMyb10‐D‐VDele genotypes were prevalent in wheat populations across continents. Despite their structural variations, the five distinct protein types exhibited comparable ability to bind the promoters of downstream genes in the flavonoid and ABA pathways, such as CHS, DFR, and NCED. Furthermore, the combination of TaMyb10 homologs was significantly associated with grain color and germination percentages. Accessions exclusively harboring TaMyb10‐D displayed red seed color and reduced germination percentages, indicating the predominant role of TaMyb10‐D compared to TaMyb10‐A and TaMyb10‐B. This comprehensive investigation enhances our understanding of the structural variations and functional divergence of TaMyb10, providing valuable insights and resources for improving PHS resistance in wheat. Significance Statement: TaPHS‐3D (TaMyb10‐D) plays a crucial role among the genes implicated in pre‐harvest sprouting resistance in wheat. Our study revealed a significant correlation between the combination of TaMyb10 homologs, grain color, and germination. Notably, TaMyb10‐D exhibited a more substantial functional impact than TaMyb10‐A and TaMyb10‐B. These findings deepen our understanding of the structural variations and functional distinctions within TaMyb10, providing valuable insights and resources for improving PHS resistance in wheat. [ABSTRACT FROM AUTHOR]

Wheat crops underpin contemporary global food security. Predominant wheat production zones in China include the Huang‐Huai‐Hai‐Plain and the Mid‐Lower Reaches of the Yangtze River, although climatic effects on productive potential across these regions vary markedly in space and time. Here, we conducted field experiments during the wheat season of 2015–2018 to examine environmental effects on growth, with fertilization and irrigation provided at levels ensuring that nutrient and water stress exposure was minimal. Yields in Huang‐Huai‐Hai‐Plain and the Mid‐Lower Reaches of the Yangtze River averaged 8950 and 4818 kg ha−1, respectively. Yield variation across regions was primarily related to spike number per unit area and grain number per spike. Maturity biomass was higher in Huang‐Huai‐Hai‐Plain; this translated into higher grain yields. Lower temperature and longer growing duration between emergence and jointing in Huang‐Huai‐Hai‐Plain afforded higher tillering and spike numbers, whereas higher growth rates from jointing to maturity resulted in higher biomass production in Huang‐Huai‐Hai‐Plain compare with the Mid‐Lower Reaches of Yangtze River. Growth rate, grain numbers and yield were positively correlated with the ratio of daily intercepted solar radiation to mean temperature during jointing to anthesis, termed photothermal quotient. Collectively, our results suggest that growth rate accounted for more variation in biomass production compared with growth duration, and the photothermal conditions in the Mid‐Lower Reaches of the Yangtze River were restrictive for spike development and yield formation. Our results help disentangle drivers of crop growth through the development of agro‐environmental conceptual frameworks, enabling a better understanding of yield variability in space and time. [ABSTRACT FROM AUTHOR]

In this study, we investigated the genetic mapping of root biomass and root/shoot ratio. We utilized a large (n = 345) bi‐parental recombinant inbred line (RIL) population from the 'Penny' × 'Yecora‐Rojo' cross to investigate the partitioning of biomass above‐ and belowground and to identify the quantitative trait loci (QTL) that influence root biomass and root/shoot ratio. Genotyping of 345 RILs by using genotyping by sequencing produced 2918 single‐nucleotide polymorphism markers by which a genome‐wide map of 3507 cM was constructed. Phenotyping was conducted in an augmented design with large pots in controlled environment. We identified two significant QTL regions, QRt.peye‐5A and QRt.peye‐5B, which control root biomass and the root/shoot ratio. QRt.peye‐5A, marking a 3.15 Mbp region on chromosome 5A, explained 11% of variations in root biomass and 9.5% of variations in root/shoot ratio, with the narrow region harbouring 28 genes. QRt.peye‐5B, marking a 12.2 Mbp region on chromosome 5B, explained 7% of variations in root/shoot ratio and harbours 104 genes. The root/shoot ratio enhancing alleles at QRt.peye‐5A and QRt.peye‐5B come from 'Penny' and 'Yecora‐Rojo' respectively. These QTL regions contains genes such as the two MADS box transcription factors on the 5A QTL that are candidate genes for Vrn1 locus, and other genes previously postulated for root traits such as a COBRA‐like COBL2 and landmark hormonal responses genes such as IAA16, IAA4 and BRI1, DREB2A‐INTERACTING PROTEIN2 (DRIP2) and bHLH92 which has a role in amelioration of stress conditions. [ABSTRACT FROM AUTHOR]

Introduction: Bio stimulants are substances and/or microorganisms that are used to improve plant growth and crop yields by modulating physiological processes and metabolism of plants. While research has primarily focused on the broad effects of bio stimulants in crops, understanding their cellular and molecular influences in plants, using metabolomic analysis, could elucidate their effectiveness and offer possibilities for fine-tuning their application. One such bio stimulant containing galacturonic acid as elicitor is used in agriculture to improve wheat vigor and strengthen resistance to lodging. Objective: However, whether a metabolic response is evolved by plants treated with this bio stimulant and the manner in which the latter might regulate plant metabolism have not been studied. Method: Therefore, the present study used 1H-NMR and LC–MS to assess changes in primary and secondary metabolites in the roots, stems, and leaves of wheat (Triticum aestivum) treated with the bio stimulant. Orthogonal partial least squares discriminant analysis effectively distinguished between treated and control samples, confirming a metabolic response to treatment in the roots, stems, and leaves of wheat. Results: Fold-change analysis indicated that treatment with the bio stimulation solution appeared to increase the levels of hydroxycinnamic acid amides, lignin, and flavonoid metabolism in different plant parts, potentially promoting root growth, implantation, and developmental cell wall maturation and lignification. Conclusion: These results demonstrate how non-targeted metabolomic approaches can be utilized to investigate and monitor the effects of new agroecological solutions based on systemic responses. [ABSTRACT FROM AUTHOR]

• Transgenerational immune priming in wheat facilitated by Trichoderma demonstrates long-lasting, broad-spectrum protection against biotic stresses. • Inheritance of priming improves disease resistance, biochemical responses, and yield-related traits. • Primed wheat shows clear superiority over non-primed counterparts. • Ability to mount targeted defense response conserves resources and enhances yield under biotic stress. • Inheritance of Trichoderma -mediated priming offers significant breakthrough for sustainable agriculture as non-chemical crop protection alternative. Plants encounter various biotic stresses in their natural habitat, prompting the exploration of innovative protective measures to bolster their immune defences against pathogens. An effective strategy involves priming plant immunity, conferring enduring and comprehensive protection. Defence priming, characterized by heightened responsiveness to attackers following prior stress exposure, intriguingly manifests transgenerationally, transmitting the memory of priming to subsequent plant generations. In our investigation, we delved into the phenomenon of transgenerational immune priming (TGIP) in wheat facilitated by Trichoderma , spanning from the parental generation (G0) to the grand progeny (G2) generation. Successful establishment of transgenerational priming in the G2 generation was achieved by initially priming the G0 generation of wheat with Trichoderma. To assess priming inheritance, seeds from the G1 generation were collected, and both primed and non-primed wheat plants' grand progeny (G2 generation) were cultivated in soil. Subsequent evaluation encompassed the disease phenotype, biochemical parameters, and yield-related traits of the G2 generation wheat when confronted with Bipolaris sorokiniana , the causal agent of spot blotch disease. Our analysis revealed that the G2 generation of primed wheat displayed superior protection against spot blotch compared to non-primed wheat. Biochemical studies indicated no activation of defensive responses in the absence of disease pressure in G2 wheat plants. However, upon pathogen challenge, the grand progeny of primed wheat exhibited a robust defence response, surpassing that of non-primed wheat. This targeted defence response enabled efficient resource utilization and mitigated yield penalties. Furthermore, under biotic stress conditions, the grand progeny of primed wheat exhibited enhanced yield parameters compared to non-primed wheat. Our findings provide conclusive evidence that Trichoderma -mediated priming against B. sorokiniana can be inherited successfully from the parental (G0) generation to the grand progeny (G2) generation of wheat. This study represents the initial documentation of Trichoderma -mediated TGIP in wheat against B. sorokiniana , holding significant promise for sustainable agriculture by offering an environmentally friendly alternative to chemical pesticides. [ABSTRACT FROM AUTHOR]

Rice residue burning poses a significant challenge in the rice-wheat cropping system of India, leading to environmental pollution, health issues, and substantial nutrient loss. To combat this menace, a three-year study (2020-21 to 2022-23) was conducted, investigating the effects of rice residue retention (RRR) and rice residue incorporation (RRI) at graded N levels (0, 50, 100, 150, and 200 kg/ha) alongside farmers' practices. The primary objective was to enhance wheat productivity, profitability, and soil fertility within this system. Pooled analysis revealed that RRR outperformed RRI at lower nitrogen doses, while RRI excelled with 7.5%, 7.4%, and 10.0% higher biological yields at higher nitrogen doses (100, 150, and 200 kg/ha). The success of RRR and RRI was attributed to 10.5% and 5.0% higher effective tiller/m2, respectively, compared to farmers' practices at 150 kg N/ha. Notably, RRR exhibited superior NDVI values at the flag leaf stage (0.76) over farmers' practices (0.73). At the 150 kg N/ha, RRR displayed a 9.6% lower cost of cultivation compared to farmers' practices, with 19.6% higher net returns at lower N levels (50 kg/ha), suggesting its greater benefits under low-input conditions. Furthermore, RRR showed the highest benefit-cost ratio (2.75) at 150 kg N/ha, followed by RRI (2.59) and farmers' practices (2.55). Over the three-year period, RRR significantly increased organic carbon content (0.49–0.54%) compared to the initial value (0.38%), affirming its long-term benefits. Consequently, the adoption of RRR by farmers is a preferable eco-friendly option over RRI and present practices for enhancing wheat productivity within the rice-wheat system. Due to 60–65% saving of fuel with the practice of zero tillage along with rice residue retention, it can reduce CO2 emission by 120 kg/ha, therefore, its implementation can reduce CO2 release by 1.62 MT in South Asia per year. Ultimately, it can meet the target of Paris Agreement of limiting global warming to 1.5 °C above pre-industrial levels and reaching net-zero CO2 emissions globally by 2050. [ABSTRACT FROM AUTHOR]

Studies on the wheat response under late sowing (LS) and salinity stress (SS) are available, however, in rice-wheat and cotton-wheat cropping systems, wheat planting is often delayed resulting in co-occurrence of LS and SS in salt affected soils. This two-year field study was conducted to evaluate the influence of foliar application of plant growth regulators (PGRs) [thiourea (TU), salicylic acid (SA) and hydrogen peroxide (H2O2); water and no application were taken as control] on the productivity, grain quality and economic returns of timely-sown (TS) and LS wheat under normal (NC) and natural saline conditions (SS; EC 11.27 dS m− 1). Delay in sowing and planting in naturally saline soils caused a significant decrease in plant growth, grain yield, grain quality and net economic returns during both years of study. Late planting and SS caused a significant reduction in grain yield reduction by 40.58% and 34.72% (LS) and 40.66% and 42.89% (SS) compared with respective controls during 2021 and 2022, respectively. However, the influence of co-occurrence of LS and SS was more devastating than the individual stress causing 62.17% and 60.18% reduction in grain yield than the respective control during 2021 and 2022, respectively. However, the application of all PGRs improved the grain yield, grain quality and economic turnover under SS and LS stress. The order of improvement in grain yield by the application of PGRs treatments was TU > SA > H2O2. In conclusion, the application of different plant growth regulators improved economic returns, grain yield and quality attributes of late-sown wheat under saline conditions. In this regard, TU application was the most effective. [ABSTRACT FROM AUTHOR]

This research aimed to prepare wheat gluten-based films activated by free and encapsulated L. majorana Origanum essential oil (MEO). Tween 80 and whey protein isolate were utilized to prepare MEO-loaded nanoemulsion (NE) and Pickering emulsion (PE), respectively. PE and NE had particle sizes of 186.7 nm and 149.5 nm, respectively. The NE had lower zeta potential and higher encapsulation efficiency. After incorporation of the obtained nanocapsules and free MEO into the gluten films at three levels (1, 3 and 5 wt%), the morphological, physical, antioxidant and antibacterial characteristics of the active films were assessed. According to the FE-SEM analysis, the surface roughness of films increased by adding free MEO and nanocapsules. XRD test revealed that the free MEO causes a decrease in the crystallinity of the film, but its encapsulated forms had no adverse effect. Improving the thermal properties of gluten films after the incorporation of PE-MEO nanocarriers was approved by TGA analysis. Adding free and encapsulated MEO led to an increase in the water solubility of films and a decrease in the WVP. The weakening effect of MEO on the mechanical characteristics of gluten films was the lowest when the PE nanocapsules were incorporated. The antioxidant activity of the films increased significantly (p < 0.05) with the addition of free and encapsulated MEO. However, the encapsulation slightly decreased the antibacterial potential of MEO against E. coli and S. aureus. To conclude, the produced active gluten film with encapsulated MEO, especially the PE one, presented considerable potential for use as active food packaging. [ABSTRACT FROM AUTHOR]

Summary: Drought is one of the major environmental constraints for wheat production world‐wide. As the progenitor and genetic reservoir of common wheat, emmer wheat is considered as an invaluable gene pool for breeding drought‐tolerant wheat.Combining GWAS and eGWAS analysis of 107 accessions, we identified 86 QTLs, 105 462 eQTLs as well as 68 eQTL hotspots associating with drought tolerance (DT) in emmer wheat.A complex regulatory network composed of 185 upstream regulator and 2432 downstream drought‐responsive candidates was developed, of which TtOTS1 was found to play a negative effect in determining DT through affecting root development.This study sheds light on revealing the genetic basis underlying DT, which will provide the indispensable genes and germplasm resources for elite drought tolerance wheat improvement and breeding. [ABSTRACT FROM AUTHOR]

Summary: Individuals were given ERSR (enzyme‐resistant starch rusks) to consume for breakfast, and its effect on blood glucose was examined. Fifty‐four people participated in this study as two groups ((WWR (whole wheat rusks): 27 and ERSR: 27)). Each rusk contains 30 g of digestible CHO. After the consumption started, measurements were made at 30‐min intervals until 120 min. In total AUC (area under the curve) values between WWR and ERSR, ERSR was significantly higher (P < 0.001). In normal‐weight individuals, the total AUC value of ERSR consumption was significantly higher than WWR (P < 0.001), and in obese individuals, no significant difference was observed. Blood glucose fluctuations were higher in ERSR compared to WWR. It was also observed that this difference was observed in normal‐weight individuals, while no such difference was observed in individuals with obesity. Although ERSR consumption seems advisable for obese individuals, it should be supported by longer studies. [ABSTRACT FROM AUTHOR]

Alternaria is an important toxigenic fungal genus endangering the quality of cereal grains. No data are available in the literature regarding the composition of Alternaria species in wheat from the main wheat‐cultivating regions of China. In this study, a total of 282 strains were isolated from wheat kernels collected in various provinces. Phylogenetic characterization was performed using two informative loci, ASA10 and ASA19, demonstrating that all strains belonged to A. alternata. A low molecular diversity was observed, which did not appear to be influenced by geographic origin. The secondary metabolite profile of the strains was evaluated in rice culture. Altertoxin I was synthesized at a high concentration by the majority of the strains, while the accumulation of altenuene was lower in both frequency and level than that of alternariol and its derivative. A. alternata did not cause readily observable symptoms on wheat spikes after spraying of the conidia at anthesis, but a higher quantity of altertoxin I and Alternaria DNA were detected in inoculated grains. Artificial inoculations of apple fruit showed that all examined strains were capable of causing typical rot symptoms and producing all four toxins to a certain degree. The widespread occurrence of A. alternata on wheat grains and its ability to synthesize various toxic metabolites may pose a serious hazard for both growers and consumers. [ABSTRACT FROM AUTHOR]

Key message: This study precisely mapped and validated a quantitative trait locus (QTL) located on chromosome 4B for flag leaf angle in wheat. Flag leaf angle (FLANG) is closely related to crop architecture and yield. We previously identified the quantitative trait locus (QTL) QFLANG-4B for FLANG on chromosome 4B, located within a 14-cM interval flanked by the markers Xbarc20 and Xzyh357, using a mapping population of recombinant inbred lines (RILs) derived from a cross between Nongda3331 (ND3331) and Zang1817. In this study, we fine-mapped QFLANG-4B and validated its associated genetic effect. We developed a BC3F3 population using ND3331 as the recurrent parent through marker-assisted selection, as well as near-isogenic lines (NILs) by selfing BC3F3 plants carrying different heterozygous segments for the QFLANG-4B region. We obtained eight recombinant types for QFLANG-4B, narrowing its location down to a 5.3-Mb region. This region contained 76 predicted genes, 7 of which we considered to be likely candidate genes for QFLANG-4B. Marker and phenotypic analyses of individual plants from the secondary mapping populations and their progeny revealed that the FLANG of the ND3331 allele is significantly higher than that of the Zang1817 allele in multiple environments. These results not only provide a basis for the map-based cloning of QFLANG-4B, but also indicate that QFLANG-4B has great potential for marker-assisted selection in wheat breeding programs designed to improve plant architecture and yield. [ABSTRACT FROM AUTHOR]

Key message: A candidate gene TaSP1 related to spike shape was cloned, and the gene-specific marker was developed to efficiently track the superior haplotype in common wheat. Spike shape, an important factor that affects wheat grain yield, is mainly defined by spike length (SPL), spikelet number (SPN), and compactness. Zhoumai32 mutant 1160 (ZM1160), a mutant obtained from ethyl methane sulfonate (EMS) treatment of hexaploid wheat variety Zhoumai32, was used to identify and clone the candidate gene that conditioned the spike shape. Genetic analysis of an F2 population derived from a cross of ZM1160 and Bainong207 suggested that the compact spike shape in ZM1160 was controlled by a single recessive gene, and therefore, the mutated gene was designated as Tasp1. With polymorphic markers identified through bulked segregant analysis (BSA), the gene was mapped to a 2.65-cM interval flanked by markers YZU0852 and MIS46239 on chromosome 7D, corresponding to a 0.42-Mb physical interval of Chinese spring (CS) reference sequences (RefSeq v1.0). To fine map TaSP1, 15 and seven recombinants were, respectively, screened from 1599 and 1903 F3 plants derived from the heterozygous F2 plants. Finally, TaSP1 was delimited to a 21.9 Kb (4,870,562 to 4,892,493 bp) Xmis48123-Xmis48104 interval. Only one high-confidence gene TraesCS7D02G010200 was annotated in this region, which encodes an unknown protein with a putative vWA domain. Quantitative reverse transcription PCR (qRT-PCR) analysis showed that TraesCS7D02G010200 was mainly expressed in the spike. Haplotype analysis of 655 wheat cultivars using the candidate gene-specific marker Xg010200p2 identified a superior haplotype TaSP1b with longer spike and more spikelet number. TaSP1 is beneficial to the improvement in wheat spike shape. [ABSTRACT FROM AUTHOR]

Key message: There is variation in stay-green within barley breeding germplasm, influenced by multiple haplotypes and environmental conditions. The positive genetic correlation between stay-green and yield across multiple environments highlights the potential as a future breeding target. Barley is considered one of the most naturally resilient crops making it an excellent candidate to dissect the genetics of drought adaptive component traits. Stay-green, is thought to contribute to drought adaptation, in which the photosynthetic machinery is maintained for a longer period post-anthesis increasing the photosynthetic duration of the plant. In other cereal crops, including wheat, stay-green has been linked to increased yield under water-limited conditions. Utilizing a panel of diverse barley breeding lines from a commercial breeding program we aimed to characterize stay-green in four environments across two years. Spatiotemporal modeling was used to accurately model senescence patterns from flowering to maturity characterizing the variation for stay-green in barley for the first time. Environmental effects were identified, and multi-environment trait analysis was performed for stay-green characteristics during grain filling. A consistently positive genetic correlation was found between yield and stay-green. Twenty-two chromosomal regions with large effect haplotypes were identified across and within environment types, with ten being identified in multiple environments. In silico stacking of multiple desirable haplotypes showed an opportunity to improve the stay-green phenotype through targeted breeding. This study is the first of its kind to model barley stay-green in a large breeding panel and has detected novel, stable and environment specific haplotypes. This provides a platform for breeders to develop Australian barley with custom senescence profiles for improved drought adaptation. [ABSTRACT FROM AUTHOR]

The rice-wheat cropping system is the largest cereal-based agricultural production system in India. It provides considerable significance to national food, nutrition, and livelihood security. However, the extensive use of resources under rice-wheat system has resulted in significant issues, including a decline in groundwater levels, indiscriminate use of fertilizers, the burning of rice residues, increased emissions of greenhouse gases, and the development of herbicide-resistant weeds which led to stagnant crop productivity and reduced profitability. This study was conducted at the research farm of ICAR-IIWBR, Karnal, India, to evaluate the combined effects of conventional and nano urea on productivity, profitability, and efficient nitrogen management strategy in wheat under rice-wheat system. The study evaluated eight treatment combinations of nitrogen application through conventionally applied urea (46% N) and foliar applied nano urea (4% N). The results of the study showed that the application of 150 kg N/ha in three equal splits as basal and just before 1st and 2nd irrigation, either alone (T2) or along with a spray of nano urea (T5), resulted in the highest grain yield and profitability. Top dressing of urea just before irrigation with a dose of nitrogen 150 kg/ha applied in three equal splits (T2) resulted in 420 kg/ha additional grain yield over top dressing at 7-10 days after irrigation with same dose (T3). Treatment T5 recorded the highest gross and net returns with 2492.5 and 1804.0 US $/ha. The study's findings suggest that efficient nitrogen management is essential for sustainable wheat production in India. The application of 150 kg N/ha in three equal splits, either alone or along with a spray of nano urea, is a promising strategy for improving wheat productivity and profitability in India. [ABSTRACT FROM AUTHOR]

Improving nutrient use efficiency and system productivity with a positive nutrient balance in rice-wheat cropping system (RWCS) is vital for long-term food security. Two-year field trials were conducted with the objective of computing the effect of different rates, time, method, and source of potassium (K) fertilization on nutrient recovery efficiency, nutrient balance, and system productivity in a dry direct-seeded RWCS with eight treatments. The two-split (half basal and half at panicle initiation) application of 60 kg K2O/ha resulted in 37.5% and 19.2% increase in recovery efficiency of K in rice and wheat, respectively over basal application of 60 kg K2O/ha. Besides, the split-application of K increased the nitrogen recovery efficiency in rice and wheat by 11.2% and 10.8%, respectively. Similarly, the phosphorus recovery efficiency was increased by 3.6% and 7.4% in rice and wheat, respectively. The split application of 60 kg K2O/ha also increased the K harvest index (% of the total K absorbed is transferred to grain) by 0.7% and 2.7% in rice and wheat, respectively over applying entire K at basal. Similarly, the system productivity (11.26 t/ha) was increased by 8% over applying entire K at basal. In the absence of top-dressing of K (30 kg/ha), two foliar-sprays of 2.5% K provide equal benefits of top dressing. Application of 90 kg K2O/ha lowered the K negative balance (−99 kg/ha/year) considerably compared to two-split application of 60 kg K2O/ha (−152.5 kg/ha/year). Thus, optimization of K fertilization in RWCS will increase the system productivity, nutrient use efficiency, and sustainability. [ABSTRACT FROM AUTHOR]

Sulfoxaflor is a systemic sulfoximine insecticide, used to control sucking pests in different agricultural crops including wheat. However, the information regarding its residual fate in wheat agroecosystem under tropical environment and the associated dietary risk are still obscure. Therefore, a supervised field experiment was conducted in wheat comprising the application of sulfoxaflor 12% (w/v) SC at 30 and 60 g a.i. ha−1 in two consecutive seasons. An optimised method for estimation of sulfoxaflor residues using modified QuEChERS technique was developed and validated. The extracting solvent ethyl acetate + cyclohexane (9 + 1 v/v) along with the clean-up combinations viz. 75 mg PSA+25 mg GCB+150 mg magnesium sulphate for wheat plant and straw and 75 mg PSA+75 mg C18 + 150 mg magnesium sulphate for grain produced satisfactory recovery, minimum matrix interference and optimum peak shape. The average recovery, repeatability and within-laboratory reproducibility of sulfoxaflor in wheat substrates ranged between 90.66% and 103.55%, 2.67–5.17% and 3.05–8.15%, respectively, and the limit of quantification was estimated 0.01 mg kg−1. Sulfoxaflor was stable up to 60 days in wheat matrices under storage (−20°C). The dissipation of sulfoxaflor in wheat plants followed first-order kinetics and the overall shorter persistence in Season I and II ranged between 1.05–1.14 and 2.44–2.47 days (T1 – T2), respectively. The deviation in the persistence of the compound between two seasons due to variation in climatic parameters was observed to be statistically significant. The estimated pre-harvest interval of sulfoxaflor ranged between 4.95–5.34 (Season I) and 11.37–11.55 days (Season II). Besides, the terminal residues of sulfoxaflor were below quantification limit in the harvested wheat products, and the estimated long-term dietary risk of sulfoxaflor was observed to be negligible. Therefore, it was expected that the application of this insecticide in wheat cultivation should pose no residual toxicity and the harvested wheat products can be considered safe for human consumption. [ABSTRACT FROM AUTHOR]

Thiamethoxam, a systemic neonicotinoid insecticide, is widely accepted for use against various chewing and sucking insect pests. In this particular study, the authors examined the dissipation kinetics and metabolism of thiamethoxam in wheat using quick, easy, cheap, effective, rugged and safe (QuEChERS) methodology combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS) over two years during the same cropping season. Residues of thiamethoxam and its metabolites in wheat plants were investigated following foliar spray of thiamethoxam at recommended dose (12.5 g a.i. ha−1) and four times the recommended dose (50.0 g a.i. ha−1) at earhead formation stage. Total residues of thiamethoxam and its metabolites in leaves at 0 day (2 h after spray) ranged from 3.69 to 14.36 mg kg−1 for the two doses over the two years. Clothianidin was the only metabolite detected in leaves at 0 day (2 h after spray); however at 7 days after spray nitroguanidine, N-desmethyl-thiamethoxam and 1-methyl-3-nitroguanidine were also detected. Total residues of thiamethoxam and its metabolites in soil at 0 day (2 h after spray) ranged from 0.23 to 0.84 mg kg−1. Thiamethoxam residue in leaves and soil followed first order kinetics with half-life ranging from 9.04 to 15.50 days for the two doses over the two study years. Residues of thiamethoxam and its metabolites in leaves, straw and grain at harvest time for both the doses were below their limit of quantification (0.01 mg kg−1). This information could be helpful for evaluating both regulatory and food safety decisions regarding use of neonicotinoids. [ABSTRACT FROM AUTHOR]

Grain protein content (GPC) is a crucial quality trait in bread wheat, which is influenced by the key transcription factor TaNAM. However, the regulatory mechanisms of TaNAM have remained largely elusive. In this study, a new role of TaNAM was unveiled in regulating nitrogen remobilisation which impacts GPC. The TaNAM knockout mutants generated by clustered regularly interspaced short palindromic repeats/Cas9 exhibited significantly delayed senescence and lower GPC, while overexpression of TaNAM‐6A resulted in premature senility and much higher GPC. Further analysis revealed that TaNAM directly activates the genes TaNRT1.1 and TaNPF5.5s, which are involved in nitrogen remobilisation. This activity aids in the transfer of nitrogen from leaves to grains for protein synthesis. In addition, an elite allele of TaNAM‐6A, associated with high GPC, was identified as a candidate gene for breeding high‐quality wheat. Overall, our work not only elucidates the potential mechanism of TaNAM‐6A affecting bread wheat GPC, but also highlights the significance of nitrogen remobilisation from senescent leaves to grains for protein accumulation. Moreover, our research provides a new target and approach for improving the quality traits of wheat, particularly the GPC. Summary statement: Grain protein content (GPC), a trait that affects both food processing quality and nutritional value, is a decisive factor for measuring the commercial value of new wheat varieties. Here, new results were revealed including: (1) We identified new targets of TaNAM‐6A, TaNRT1.1, and TaNPF5.5s, which are indispensable for nitrogen remobilisation from leaves to grains, especially during grain filling; (2) We identified an elite allele in natural populations, TaNAM‐6A‐Hap1, for wheat GPC that could be used in the genetic improvement of wheat quality. [ABSTRACT FROM AUTHOR]

Objective: The main objective of this study was to determine available energy and nutritional digestibility of extruded cereals and the effect of extrusion on the nutritional value of feed ingredients, aiming to provide scientific basis for efficient application of extrusion in the diets of growing pigs. Methods: In Exp. 1, 48 crossbred growing pigs (Duroc×Landrace×Yorkshire) with an initial body weight (BW) of 34.6±2.2 kg were selected and fed with eight diets (non-extrusion or extrusion) to determine the digestible energy (DE), metabolizable energy (ME), and nutrients digestibility. Eight diets included extruded grains (barley, wheat, sorghum, or broken rice), while four had unprocessed grains. In Exp. 2, 9 diets were formulated including 4 cereals with extrusion or non-extrusion and a N-free diet. In addition, 9 growing pigs (BW = 22.3±2.8 kg) were fitted with T-cannula in the distal ileum and arranged in a 9×6 Youden square design. Results: Results show that apparent total tract digestibility of gross energy, dry matter, organic meal, ether extract, neutral and acid detergent fiber was not affected by the extrusion process and there was no interaction between cereal type and extrusion treatment on DE, ME. However, the apparent total tract digestibility for crude protein (CP) increased markedly (p<0.05). The standardized ileal digestibility (SID) of all amino acids (AA) except for leucine remarkably increased by extrusion (p<0.05). There was an interaction on the SID of arginine, leucine, isoleucine, methionine, phenylalanine, cystine, and tyrosine in growing pigs between type of grain and extrusion treatment (p<0.05). Conclusion: Extrusion increased the ileal digestibility of CP and most AA in cereals, however, the DE and ME of cereals were not affected in growing pigs. [ABSTRACT FROM AUTHOR]

The present study aimed to examine the relationship between canopy air temperature difference and vapor pressure deficit (VPD) in wheat crops under normal or nonstressfull conditions. The treatments were undertaken on five plots, having randomized block design (RBD), each maintained at different levels of soil moisture having full irrigation; no irrigation; and 10%, 30%, and 50% soil moisture. Then canopy air temperature difference was regressed against VPD to generate non-water stress and maximum water stress baselines, and the crop water stress index (CWSI) was computed using empirical approach-baseline methods at different soil moisture deficits. It was found that irrigation treatment at 30% soil moisture deficit yielded the maximum water use efficiency. The canopy air temperature difference and VPD resulted in linear relationships, and the slope (m) and intercept (c) for lower baseline of preheading and postheading stages of wheat crop were found as m=−2.371 , c=−1.659 ; and m=−1.8952 , c=−2.32 , for the crop season of 2018–2019. Similarly, the non-water stress baseline equation in the season of 2019–2020 had m=−1.7184 , c=−2.3009 ; and m=−1.8137 , c=−1.9176 for preflowering and postflowering stages of wheat, respectively. The CWSI was determined by using the developed empirical equations for three irrigation schedules of different maximum allowable depletion (MAD) of available soil water (ASW). The developed CWSI may have the potential to improve irrigation scheduling of wheat in India. The study shows practical applications for enhancing wheat cultivation under varying soil moisture conditions. First, it recommends irrigating at 30% soil moisture deficit to maximize water use efficiency, aiding farmers in balancing crop yield and water conservation. Second, established relationships between canopy air temperature difference and VPD allow for the assessment of water stress. By utilizing regression equations, farmers can estimate the CWSI across soil moisture levels, guiding irrigation scheduling during critical growth stages. Third, the developed empirical equations enable real-time prediction of water stress. Monitoring the canopy air temperature difference and VPD offers insights into plant health, helping with informed decisions on irrigation and fertilization. Last, the findings are relevant for water-scarce regions like India, where tailored CWSI equations can be integrated into irrigation systems, promoting sustainable practices under a changing climate. This study may help farmers with practical tools for water-efficient wheat cultivation, fostering informed choices for sustainable agriculture, particularly in water-scarce regions. [ABSTRACT FROM AUTHOR]

MOCA1 encodes the last key glucuronosyltransferase for ionic stress sensor glycosyl inositol phosphoryl-ceramide (GIPCs) biosynthesis in Arabidopsis, which indicates that the MOCA gene family play important role in plant tolerance to salt stress. However, the isolation and function of MOCAs in staple crops have not been reported and the downstream targets of MOCAs in salt stress tolerance signalling pathway are not clear. In this study, we identified 110 MOCA genes in wheat which were classified into five clades and they differed in gene structure, protein length, conserved motifs and expression profiles in different tissues and under salt stress. TaMOCA1 was selected for further functional study in response to salt stress. TaMOCA1 was rapidly induced by NaCl treatment. The 35S::TaMOCA1-GFP construction showed the cell nucleus and cytoplasm location in wheat protoplast. TaMOCA1 over-expressing Arabidopsis seedlings formed longer primary roots and more lateral roots than the wild type ones under 50 mM NaCl treatment. The over-expressing Arabidopsis had higher expression levels of HKT1, but lower expression levels of NHX1 and SOS genes than the wild type. Also, the transgenic plants had higher SOD activity and lower MDA content than the wild Arabidopsis seedling under salt stress. These results may indicate that TaMOCA1 increases salt stress tolerance through decreasing Na+ loading from the xylem parenchyma cells to the xylem via SOS1 and HKT1, hence lowering root-to-shoot delivery of Na+ and superior antioxidant ability. All these results lay a foundation for further functional study of MOCAs in wheat. [ABSTRACT FROM AUTHOR]

Fusarium head blight (FHB) is a devastating fungal disease affecting different cereals, particularly wheat, and poses a serious threat to global wheat production. Chitinases and β-glucanases are two important proteins involved in lysing fungal cell walls by targeting essential macromolecular components, including chitin and β-glucan micro fibrils. In our experiment, a transgenic wheat (Triticum aestivum) was generated by introducing chitinase and glucanase genes using Biolistic technique and Recombinant pBI121 plasmid (pBI-ChiGlu (-)). This plasmid contained chitinase and glucanase genes as well as nptII gene as a selectable marker. The expression of chitinase and glucanase was individually controlled by CaMV35S promoter and Nos terminator. Immature embryo explants from five Iranian cultivars (Arta, Moghan, Sisun, Gascogen and A-Line) were excised from seeds and cultured on callus induction medium to generate embryonic calluses. Embryogenic calluses with light cream color and brittle texture were selected and bombarded using gold nanoparticles coated with the recombinant pBI-ChiGlu plasmid. Bombarded calluses initially were transferred to selective callus induction medium, and later, they were transfferd to selective regeneration medium. The selective agent was kanamycin at a concentration of 25 mg/l in both media. Among five studied cultivars, A-Line showed the highest transformation percentage (4.8%), followed by the Sisun, Gascogen and Arta in descending order. PCR and Southern blot analysis confirmed the integration of genes into the genome of wheat cultivars. Furthermore, in an in-vitro assay, the growth of Fusarium graminearum was significantly inhibited by using 200 μg of leaf protein extract from transgenic plants. According to our results, the transgenic plants (T1) showed the resistance against Fusarium when were compared to the non-transgenic plants. All transgenic plants showed normal fertility and no abnormal response was observed in their growth and development. [ABSTRACT FROM AUTHOR]

Pleiotropy is frequently detected in agronomic traits of wheat (Triticum aestivum). A locus on chromosome 4B, QTn/Ptn/Sl/Sns/Al/Tgw/Gl/Gw.caas-4B, proved to show pleiotropic effects on tiller, spike, and grain traits using a recombinant inbred line (RIL) population of Qingxinmai × 041133. The allele from Qingxinmai increased tiller numbers, and the allele from line 041133 produced better performances of spike traits and grain traits. Another 52 QTL for the eight traits investigated were detected on 18 chromosomes, except for chromosomes 5D, 6D, and 7B. Several genes in the genomic interval of the locus on chromosome 4B were differentially expressed in crown and inflorescence samples between Qingxinmai and line 041133. The development of the KASP marker specific for the locus on chromosome 4B is useful for molecular marker-assisted selection in wheat breeding. [ABSTRACT FROM AUTHOR]

Summary Increasing crop yield depends on selecting and utilizing pleiotropic genes/alleles to improve multiple yield‐related traits (YRTs) during crop breeding. However, synergistic improvement of YRTs is challenging due to the trade‐offs between YRTs in breeding practices. Here, the favourable haplotypes of the TaCYP78A family are identified by analysing allelic variations in 1571 wheat accessions worldwide, demonstrating the selection and utilization of pleiotropic genes to improve yield and related traits during wheat breeding. The TaCYP78A family members, including TaCYP78A3, TaCYP78A5, TaCYP78A16, and TaCYP78A17, are organ size regulators expressed in multiple organs, and their allelic variations associated with various YRTs. However, due to the trade‐offs between YRTs, knockdown or overexpression of TaCYP78A family members does not directly increase yield. Favourable haplotypes of the TaCYP78A family, namely A3/5/16/17Ap‐Hap II, optimize the expression levels of TaCYP78A3/5/16/17‐A across different wheat organs to overcome trade‐offs and improve multiple YRTs. Different favourable haplotypes have both complementary and specific functions in improving YRTs, and their aggregation in cultivars under strong artificial selection greatly increase yield, even under various planting environments and densities. These findings provide new support and valuable genetic resources for molecular breeding of wheat and other crops in the era of Breeding 4.0. [ABSTRACT FROM AUTHOR]

Grain yield plateau is a serious concern in many countries, including Italy. A specific‐adaptative strategy might apply to contrast this unfavourable condition. This study aimed to investigate the gain in grain yield and yield‐related traits of bread wheat in Italy over a 16‐year period. A historical dataset concerning 105 sites across Italy and observations on grain yield, heading date, plant height and thousand kernel weight was used. The target population of environments (TPEs) were defined using several environmental parameters. The results showed that while there was a general increase in thousand kernel weight over the 16 years, there was no significant improvement in grain yield and heading date. By contrast, plant height showed a slight decrease over the years. The study also identified five TPEs presenting different climate scenarios in Italy. The TPEs showed varying levels of performance for the traits of interest, with the Po valley (TPE4) showing the highest values for grain yield and thousand kernel weight. The study also identified the best‐performing genotypes for each TPE, providing valuable insights for future wheat breeding programmes in Italy. [ABSTRACT FROM AUTHOR]

Background: As the greenhouse effect intensifies, global temperatures are steadily increasing, posing a challenge to bread wheat (Triticum aestivum L.) production. It is imperative to comprehend the mechanism of high temperature tolerance in wheat and implement breeding programs to identify and develop heat-tolerant wheat germplasm and cultivars. Results: To identify quantitative trait loci (QTL) related to heat stress tolerance (HST) at seedling stage in wheat, a panel of 253 wheat accessions which were re-sequenced used to conduct genome-wide association studies (GWAS) using the factored spectrally transformed linear mixed models (FaST-LMM). For most accessions, the growth of seedlings was found to be inhibited under heat stress. Analysis of the phenotypic data revealed that under heat stress conditions, the main root length, total root length, and shoot length of seedlings decreased by 47.46%, 49.29%, and 15.19%, respectively, compared to those in normal conditions. However, 17 varieties were identified as heat stress tolerant germplasm. Through GWAS analysis, a total of 115 QTLs were detected under both heat stress and normal conditions. Furthermore, 15 stable QTL-clusters associated with heat response were identified. By combining gene expression, haplotype analysis, and gene annotation information within the physical intervals of the 15 QTL-clusters, two novel candidate genes, TraesCS4B03G0152700/TaWRKY74-B and TraesCS4B03G0501400/TaSnRK3.15-B, were responsive to temperature and identified as potential regulators of HST in wheat at the seedling stage. Conclusions: This study conducted a detailed genetic analysis and successfully identified two genes potentially associated with HST in wheat at the seedling stage, laying a foundation to further dissect the regulatory mechanism underlying HST in wheat under high temperature conditions. Our finding could serve as genomic landmarks for wheat breeding aimed at improving adaptation to heat stress in the face of climate change. [ABSTRACT FROM AUTHOR]

Background: The increasing impacts of heat stress on wheat production due to climate change has entailed the development of heat-resilient crop varieties. To address this, two hundred recombinant inbred lines (RILs) derived from a cross between WH711/WH1021 were evaluated in a randomized block design (RBD) with two replications at CCSHAU, Hisar, during 2018-19 under heat stress and non-stress conditions. Heat stress was induced by altering the date of sowing so that the grain filling stage coincide with heat stress. Results: Heat stress adversely affects RILs performance, as illustrated by alterations in phenotypic traits. Highest coefficients of variations were recorded for TAA, CTD 1, WUE, CTD 2, Cc and A under non-stress and heat stress conditions whereas gs, WUEi and GY under non-stress and SPAD 1, SPAD 2, GY and NDVI 2 under heat-stress conditions recorded moderate estimates of coefficient of variations. CTD 2, TAA, E, WUE and A displayed a significant occurrence of both high heritability and substantial genetic advance under non-stress. Similarly, CTD 2, NDVI 2, A, WUEi, SPAD 2, gs, E, Ci, MDA and WUE exhibited high heritability with high genetic advance under heat-stress conditions. Conclusions: Complementary and duplicate types of interactions with number of controlling genes were observed for different parameters depending on the traits and environments. RILs 41, 42, 59, 74, 75, 180 and 194 were categorized as heat tolerant RILs. Selection preferably for NDVI 1, RWC, TAA, A, E and WUEi to accumulate heat tolerance favorable alleles in the selected RILs is suggested for development of heat resilient genotypes for sustainable crop improvement. The results showed that traits such as such as NDVI, RWC, TAA, A, E, and WUEi, can be effective for developing heat-resilient wheat genotypes and ensuring sustainable crop improvement. [ABSTRACT FROM AUTHOR]

A well‐developed root system is essential for efficient nutrient and water uptake. We phenotyped a set of 172 Triticum durum–Aegilops speltoides backcross introgression lines (BILs) for various root architecture traits during 2019–2020 and 2020–2021 cropping seasons. The roots were sampled at the maximum tillering stage, and data on various root architecture traits were recorded. The quantitative trait loci (QTL) mapping was carried out using 5672 polymorphic SNPs obtained from genotyping‐by‐sequencing. A total of 21 QTLs were detected for various root architecture traits on chromosomes 1A, 2A, 2B, 3B, 5A and 6B. Stable QTLs were detected for total root length, number of root tips and root dry weight over the two seasons. Candidate genes were identified by scanning the physical interval corresponding to the linkage disequilibrium (LD) decay flanking the SNPs linked to the stable QTLs. In silico expression studies of postulated candidate genes revealed root‐specific upregulation of some of the genes. These QTLs can be used in breeding programmes after the development and validation of suitable marker assays. [ABSTRACT FROM AUTHOR]

Participatory plant breeding (PPB) is a collaborative process between farmers, plant breeders and researchers to create germplasm specifically bred for target environments. We sought to examine the yield performance and adaptability of genotypes from an organic PPB wheat programme under organic management across the Canadian prairies. We evaluated 25 farmer genotypes and 6 commercial cultivars in locations in Alberta, Saskatchewan and Manitoba, totalling 12 organic environments. The top performers most responsive to higher yield environments were three farmer genotypes (BL34‐SW, BL43C‐TM and BJ13‐GW) and one check cultivar (Vesper). Genotype plus genotype by environment (GGE) biplot analysis indicated that one farmer genotype (BL23‐AS) and one check cultivar (Vesper) demonstrated high yield and greater organic adaptation than other genotypes tested. Two registered cultivars (AAC Brandon and Jake) had low yield and poor adaptation, as did one farmer genotype (PWA10B‐LD). Yield was positively and strongly correlated with height, anthesis and mature biomass and kernel number per unit area. The results provide evidence that early generation farmer selection is an effective breeding strategy for discovering wheat genotypes with high yield and excellent adaptability to organic production systems in Canada. [ABSTRACT FROM AUTHOR]

Background: Soil salinity is one of the major menaces to food security, particularly in dealing with the food demand of the ever-increasing global population. Production of cereal crops such as wheat is severely affected by soil salinity and improper fertilization. The present study aimed to examine the effect of selected microbes and poultry manure (PM) on seedling emergence, physiology, nutrient uptake, and growth of wheat in saline soil. A pot experiment was carried out in research area of Institute of Soil and Environmental Sciences, University of Agriculture, Faisalabad, Pakistan. Saline soil (12 dS m− 1 w/w) was developed by spiking using sodium chloride, and used in experiment along with two microbial strains (i.e., Alcaligenes faecalis MH-2 and Achromobacter denitrificans MH-6) and PM. Finally, wheat seeds (variety Akbar-2019) were sown in amended and unamended soil, and pots were placed following a completely randomized design. The wheat crop was harvested after 140 days of sowing. Results: The results showed a 10–39% increase (compared to non-saline control) in agronomic, physiological, and nutritive attributes of wheat plants when augmented with PM and microbes. Microbes together with PM significantly enhanced seedling emergence (up to 38%), agronomic (up to 36%), and physiological (up to 33%) in saline soil as compared to their respective unamended control. Moreover, the co-use of microbes and PM also improved soil's physicochemical attributes and enhanced N (i.e., 21.7%-17.1%), P (i.e., 24.1-29.3%), and K (i.e., 28.7%-25.3%) availability to the plant (roots and shoots, respectively). Similarly, the co-use of amendments also lowered the Na+ contents in soil (i.e., up to 62%) as compared to unamended saline control. This is the first study reporting the effects of the co-addition of newly identified salt-tolerant bacterial strains and PM on seedling emergence, physiology, nutrient uptake, and growth of wheat in highly saline soil. Conclusion: Our findings suggest that co-using a multi-trait bacterial culture and PM could be an appropriate option for sustainable crop production in salt-affected soil. [ABSTRACT FROM AUTHOR]

Background: Growing wheat under climate change scenarios challenges, scientists to develop drought and heat-tolerant genotypes. The adaptive traits should therefore be explored and engineered for this purpose. Thus, this study aimed to dissect surface traits and optimizing the leaf architecture to enhance water use efficiency (WUE) and grain yield. Twenty-six wheat genotypes were assessed for five novel leaf traits (NLTs: leaf prickle hairs, groove type, rolling, angle and wettability) under normal, drought and heat conditions following triplicated factorial randomized complete block design (RCBD). The data for NLTs, physiological traits (stomatal conductance, WUE, transpiration, and photosynthesis), and standard morphological and yield traits were recorded. Leaves were sampled at the stem elongation stage (Zadoks 34) to measure the leaf water content (%), contact angle, and to obtain pictures through scanning electron microscopy (SEM). The air moisture harvesting efficiency was evaluated for five selected genotypes. The ideotype concept was applied to evaluate the best-performing genotypes. Results: The correlation analysis indicated that long leaf prickle hairs (> 100 μm), short stomatal aperture and density (40–60 mm− 2), inward to spiral leaf rolling, medium leaf indentation, low contact angle hysteresis (< 10°), and cuticular wax were positively associated with WUE. This, in turn, was significantly correlated to grain yield. Thus, the genotypes (E-1) with these traits and alternate leaf wettability had maximum grain yield (502 g m− 2) and WUE supported with high photosynthesis rate, and relative water content (94 and 75% under normal and stress conditions, respectively). However, the genotype (1-hooded) with dense leaf hairs on edges but droopy leaves, spiral leaf rolling, and lighter groove, also performed better in terms of grain yield (450 g m− 2) under heat stress conditions by maintaining high photosynthesis and WUE with low stomatal conductance and transpiration rate. Conclusion: The SEM analysis verified that the density of hairs on the leaf surface and epicuticular wax contributes towards alternate wettability patterns thereby increasing the water-use efficiency and yield of the wheat plant. This study paves a way towards screening and and developing heat and drought-tolerant cultivars that are water-saving and climate-resilient. [ABSTRACT FROM AUTHOR]

AbstractStem rust of barley and wheat is caused by the obligate pathogen Puccinia graminis f. sp. tritici (Pgt) and stem rust of oat is caused by P. graminis f. sp. avenae (Pga). Stem rust can be a very destructive disease of cereal crops and, until the development of resistant host varieties, was responsible for millions of dollars of losses to producers. Genetic host resistance is the most common and effective method to control stem rust on cereals. Knowledge of the virulence genes and races present in the pathogen population is important to identify effective host resistance genes for use by cereal plant breeders. The objectives of this study were to determine the incidence and severity of P. graminis in wheat, barley and oat in Manitoba, Canada, and assess the virulence frequencies and races of isolates collected from Manitoba, Saskatchewan and Ontario, Canada during 2020 to 2022. Stem rust incidence and severity was very light in Manitoba in 2020, 2021 and 2022. Virulence was not observed on resistance genes Sr30, Sr24 and Sr31 from Canadian collections of Pgt isolates made during 2020 to 2022. Race QFCSC was the most common race of Pgt in Canada, and races MCCFC and TPMKC were also common in Manitoba in 2022. Virulence to resistance genes Pg6, Pg10 and Pg16 was not observed among Pga isolates. The most common race of Pga from Manitoba and Saskatchewan was TGN, followed by SGB and TJS. The most frequent Pga races were TDJ, TDD and TGN in Ontario. [ABSTRACT FROM AUTHOR]

Accurate disease severity assessment is critical for plant breeders, as it directly impacts crop yield. While hyperspectral remote sensing has shown promise for disease severity assessment in breeding experiments, most studies have focused on either leaf or canopy levels, neglecting the valuable insights gained from a combined approach. Moreover, many studies have centered on experiments involving a single disease and a few genotypes. However, this approach needs to accurately represent the challenges encountered in field conditions, where multiple diseases could occur simultaneously. To address these gaps, our current study analyses a combination of diseases, yellow rust, brown rust, and yellow leaf spots, collectively evaluated as the percentage of the diseased leaf area relative to the total leaf area (DA) at both leaf and canopy levels, using hyperspectral data from an ASD field spectrometer. We quantitatively estimate overall disease severity across fifty-two winter durum wheat genotypes categorized into early (medium milk) and late (late milk) groups based on the phenophase. Chlorophyll content (CC) within each group is studied concerning infection response, and a correlation analysis is conducted for each group with nine vegetation indices (VI) known for their sensitivity to rust and leaf spot infection in wheat. Subsequent parametric (linear and polynomial) and nonparametric (partial least squares and kernel ridge) regression analyses were performed using all available spectral bands. We found a significant reduction in Leaf CC (>30%) in the late group and Canopy CC (<10%) for both groups. YROI and LRDSI_1 are the VIs that exhibited notable and strong negative correlations with Leaf CC in the late group, with a Pearson coefficient of −0.73 and −0.72, respectively. Interestingly, spectral signatures between the early and late disease groups at both leaf and canopy levels exhibit opposite trends. The regression analysis showed we could retrieve leaf CC only for the late group, with R2 of 0.63 and 0.42 for the cross-validation and test datasets, respectively. Canopy CC retrieval required separate models for each group: the late group achieved R2 of 0.61 and 0.37 (cross-validation and test), while the early group achieved R2 of 0.48 and 0.50. Similar trends were observed for canopy DA, with separate models for early and late groups achieving comparable R2 values of 0.53 and 0.51 (cross-validation) and 0.35 and 0.36 (test), respectively. All of our models had medium accuracy and tended to overfit. In this study, we analyzed the spectral response mechanism associated with durum wheat diseases, offering a novel crop disease severity assessment approach. Additionally, our findings serve as a foundation for detecting resistant wheat varieties, which is the most economical and environmentally friendly management strategy for wheat leaf diseases on a large scale in the future. [ABSTRACT FROM AUTHOR]

To explore the possible novel microRNA (miRNA) regulatory pathways in Zhengmai 1860, a newly cultivated drought-tolerant wheat (Triticum aestivum L.) cultivar, miRNA transcriptome sequencing of the flag leaves of Zhengmai 1860, drought-sensitive variety Zhoumai 18, and drought-resistant variety Bainong 207 was performed during the grain filling stage. We also observed changes in the chloroplast ultrastructure, phytohormone levels, and antioxidant- and photosynthesis-related physiological indicators in three wheat varieties. The results showed that the flag leaves of the drought-tolerant variety Zhengmai 1860 had higher chlorophyll contents and net photosynthetic rates than those of Zhoumai 18 under drought stress during the grain filling stage; in addition, the chloroplast structure was more complete. However, there was no significant difference between Zhengmai 1860 and Bainong 207. MiRNA transcriptome analysis revealed that the differential expression of the miRNAs and mRNAs exhibited variable specificity. The KEGG pathway enrichment results indicated that most of the genes were enriched in the MAPK signaling pathway, plant hormone signal transduction, photosynthetic antennae protein, and amino acid and carbohydrate metabolism. In the drought-tolerant cultivar Zhengmai 1860, tae-miR408 was targeted to regulate the allene oxide synthase (AOS) gene, inhibit its expression, reduce the AOS content, and decrease the synthesis of jasmonic acid (JA) and abscisic acid (ABA). The results of this study suggest that Zhengmai 1860 could improve the photosynthetic performance of flag leaves by inhibiting the expression of genes involved in the JA pathway through miRNAs under drought conditions. Moreover, multiple miRNAs may target chlorophyll, antioxidant enzymes, phytohormone signal transduction, and other related pathways; thus, it is possible to provide a more theoretical basis for wheat molecular breeding. [ABSTRACT FROM AUTHOR]

The role of lncRNA and circRNA in wheat grain development is still unclear. The objectives of this study were to characterize the lncRNA and circRNA in the wheat grain development and to construct the interaction network among lncRNA, circRNA, and their target miRNA to propose a lncRNA–circRNA–miRNA module related to wheat grain development. Full transcriptome sequencing on two wheat varieties (Annong 0942 and Anke 2005) with significant differences in 1000-grain weight at 10 d (days after pollination), 20 d, and 30 d of grain development were conducted. We detected 650, 736, and 609 differentially expressed lncRNA genes, and 769, 1054, and 1062 differentially expressed circRNA genes in the grains of 10 days, 20 days and 30 days after pollination between Annong 0942 and Anke 2005, respectively. An analysis of the lncRNA–miRNA and circRNA–miRNA targeting networks reveals that circRNAs exhibit a more complex and extensive interaction network in the development of cereal grains and the formation of grain shape. Central to these interactions are tae-miR1177, tae-miR1128, and tae-miR1130b-3p. In contrast, lncRNA genes only form a singular network centered around tae-miR1133 and tae-miR5175-5p when comparing between varieties. Further analysis is conducted on the underlying genes of all target miRNAs, we identified TaNF-YB1 targeted by tae-miR1122a and TaTGW-7B targeted by miR1130a as two pivotal regulatory genes in the development of wheat grains. The quantitative real-time PCR (qRT-PCR) and dual-luciferase reporter assays confirmed the target regulatory relationships between miR1130a-TaTGW-7B and miR1122a-TaNF-YB1. We propose a network of circRNA and miRNA-mediated gene regulation in the development of wheat grains. [ABSTRACT FROM AUTHOR]

Floods induce hypoxic stress and reduce wheat growth. On the other hand, rice is a semi-aquatic plant and usually grows even when partially submerged. To clarify the dynamic differences in the cellular mechanism between rice and wheat under flooding stress, morphological and biochemical analyses were performed. Although the growth of wheat in the early stage was significantly suppressed due to flooding stress, rice was hardly affected. Amino-acid analysis revealed significant changes in amino acids involved in the gamma-aminobutyric acid (GABA) shunt and anaerobic/aerobic metabolism. Flood stress significantly increased the contents of GABA and glutamate in wheat compared with rice, though the abundances of glutamate decarboxylase and succinyl semialdehyde dehydrogenase did not change. The abundance of alcohol dehydrogenase and pyruvate carboxylase increased in wheat and rice, respectively. The contents of aspartic acid and pyruvic acid increased in rice root but remained unchanged in wheat; however, the abundance of aspartate aminotransferase increased in wheat root. These results suggest that flooding stress significantly inhibits wheat growth through upregulating amino-acid metabolism and increasing the alcohol-fermentation system compared to rice. When plant growth is inhibited by flooding stress and the aerobic-metabolic system is activated, GABA content increases. [ABSTRACT FROM AUTHOR]

Phosphorus (P) is a crucial macronutrient for plant growth and development. Basic metabolic processes regulate growth; however, the molecular detail of these pathways under low phosphorous (LP) in wheat is still unclear. This study aims to elucidate the varied regulatory pathways responses to LP stress in wheat genotypes. Phenotypic, physiological, and transcriptome analyses were conducted on Fielder (P efficient) and Ardito (P inefficient) wheat genotypes after four days of normal phosphorous (NP) and LP stress. In response to LP, Fielder outperformed Ardito, displaying higher chlorophyll content-SPAD values (13%), plant height (45%), stem diameter (12%), shoot dry weight (42%), and root biomass (75%). Root structure analysis revealed that Fielder had greater total root length (50%), surface area (56%), volume (15%), and diameter (4%) than Ardito under LP. These findings highlight Fielder's superior performance and adaptation to LP stress. Transcriptome analysis of wheat genotype roots identified 3029 differentially expressed genes (DEGs) in Fielder and 1430 in Ardito, highlighting LP-induced changes. Key DEGs include acid phosphatases (PAPs), phosphate transporters (PHT1 and PHO1), SPX, and transcription factors (MYB, bHLH, and WRKY). KEGG enrichment analysis revealed key pathways like plant hormones signal transduction, biosynthesis of secondary metabolites, and carbohydrate biosynthesis metabolism. This study unveils crucial genes and the intricate regulatory process in wheat's response to LP stress, offering genetic insights for enhancing plant P utilization efficiency. [ABSTRACT FROM AUTHOR]

The presence of incompatibility alleles in primary amphidiploids constitutes a reproductive barrier in newly synthesized wheat-rye hybrids. To overcome this barrier, the genome stabilization process includes large-scale chromosome rearrangements. In incompatible crosses resulting in fertile amphidiploids, the elimination of one of the incompatible alleles Eml-A1 or Eml-R1b can occur already in the somatic tissue of the wheat × rye hybrid embryo. We observed that the interaction of incompatible loci Eml-A1 of wheat and Eml-R1b of rye after overcoming embryo lethality leads to hybrid sterility in primary triticale. During subsequent seed reproductions (R1, R2 or R3) most of the chromosomes of A, B, D and R subgenomes undergo rearrangement or eliminations to increase the fertility of the amphidiploid by natural selection. Genotyping-by-sequencing (GBS) coverage analysis showed that improved fertility is associated with the elimination of entire and partial chromosomes carrying factors that either cause the disruption of plant development in hybrid plants or lead to the restoration of the euploid number of chromosomes (2n = 56) in the absence of one of the incompatible alleles. Highly fertile offspring obtained in compatible and incompatible crosses can be successfully adapted for the production of triticale pre-breeding stocks. [ABSTRACT FROM AUTHOR]

Polyamines, such as putrescine, spermidine, and spermine, are crucial for plant defense against both abiotic and biotic stresses. Putrescine is also known as a significant inducer of deoxynivalenol (DON) production in Fusarium graminearum, the primary causal agent of Fusarium head blight (FHB). However, the impact of other polyamines on DON production and whether modifying polyamine biosynthesis could improve wheat resistance to FHB are currently unknown. In this study, we demonstrate that key precursor components of putrescine synthesis, including arginine, ornithine, and agmatine, can induce DON production, albeit to a lesser extent than putrescine in trichothecene biosynthesis-inducing (TBI) culture under the same total nitrogen conditions. Intriguingly, spermidine and spermine, downstream products of putrescine in the polyamine biosynthesis pathway, do not induce DON production under the same conditions. Additionally, externally applying either spermidine or spermine to wheat heads significantly reduces the diseased spikelet number caused by F. graminearum. Furthermore, our results show that overexpression of the wheat spermidine synthase (SPDS) gene TaSPDS-7D1 significantly enhances the spermidine content and wheat resistance to FHB. In addition, the TaSPDS-7D1-overexpressing line OE3 exhibited a 1000-grain weight and plant height increase compared to the wild type. Our findings reveal that overexpression of the spermidine synthase gene can enhance wheat resistance to FHB without compromising wheat yield. [ABSTRACT FROM AUTHOR]

SUMMARY: Hybrid breeding is a promising strategy to quickly improve wheat yield and stability. Due to the usefulness of the Rht 'Green Revolution' dwarfing alleles, it is important to gain a better understanding of their impact on traits related to hybrid development. Traits associated with cross‐pollination efficiency were studied using Near Isogenic Lines carrying the different sets of alleles in Rht genes: Rht1 (semi‐dwarf), Rht2 (semi‐dwarf), Rht1 + 2 (dwarf), Rht3 (extreme dwarf), Rht2 + 3 (extreme dwarf), and rht (tall) during four growing seasons. Results showed that the extreme dwarfing alleles Rht2 + 3, Rht3, and Rht1 + 2 presented the greatest effects in all the traits analyzed. Plant height showed reductions up to 64% (Rht2 + 3) compared to rht. Decreases up to 20.2% in anther length and 33% in filament length (Rht2 + 3) were observed. Anthers extrusion decreased from 40% (rht) to 20% (Rht1 and Rht2), 11% (Rht3), 8.3% (Rht1 + 2), and 6.5% (Rht2 + 3). Positive correlations were detected between plant height and anther extrusion, anther, and anther filament lengths, suggesting the negative effect of dwarfing alleles. Moreover, the magnitude of these negative impacts depends on the combination of the alleles: Rht2 + 3 > Rht3/Rht1 + 2 > Rht2/Rht1 > rht (tall). Reductions were consistent across genotypes and environments with interactions due to magnitude effects. Our results indicate that Rht alleles are involved in multiple traits of interest for hybrid wheat production and the need to select alternative sources for reduced height/lodging resistance for hybrid breeding programs. Significance Statement: Hybrid wheat is a promising strategy to increase grain yield. The negative effect on floral traits with relevance for hybrid breeding of different Rht genes using near‐isogenic lines was reported. [ABSTRACT FROM AUTHOR]

Background: In common wheat (Triticum aestivum L.), allelic variations in the high-molecular-weight glutenin subunits Glu-B1 locus have important effects on grain end-use quality. The Glu-B1 locus consists of two tightly linked genes encoding x- and y-type subunits that exhibit highly variable frequencies. However, studies on the discriminating markers of the alleles that have been reported are limited. Here, we developed 11 agarose gel-based PCR markers for detecting Glu-1Bx and Glu-1By alleles. Results: By integrating the newly developed markers with previously published PCR markers, nine Glu-1Bx locus alleles (Glu-1Bx6, Glu-1Bx7, Glu-1Bx7*, Glu-1Bx7OE, Glu-1Bx13, Glu-1Bx14(−), Glu-1Bx14(+)/Bx20, and Glu-1Bx17) and seven Glu-1By locus alleles (Glu-1By8, Glu-1By8*, Glu-1By9, Glu-1By15/By20, Glu-1By16, and Glu-1By18) were distinguished in 25 wheat cultivars. Glu-1Bx6, Glu-1Bx13, Glu-1Bx14(+)/Bx20, Glu-1By16, and Glu-1By18 were distinguished using the newly developed PCR markers. Additionally, the Glu-1Bx13 and Glu-1Bx14(+)/Bx20 were distinguished by insertions and deletions in their promoter regions. The Glu-1Bx6, Glu-1Bx7, Glu-1By9, Glu-1Bx14(−), and Glu-1By15/By20 alleles were distinguished by using insertions and deletions in the gene-coding region. Glu-1By13, Glu-1By16, and Glu-1By18 were dominantly identified in the gene-coding region. We also developed a marker to distinguish between the two Glu-1Bx14 alleles. However, the Glu-1Bx14(+) + Glu-1By15 and Glu-1Bx20 + Glu-1By20 allele combinations could not be distinguished using PCR markers. The high-molecular-weight glutenin subunits of wheat varieties were analyzed by ultra-performance liquid chromatography and sodium dodecyl sulfate–polyacrylamide gel electrophoresis, and the findings were compared with the results of PCR analysis. Conclusions: Seven Glu-1Bx and four Glu-1By allele detection markers were developed to detect nine Glu-1Bx and seven Glu-1By locus alleles, respectively. Integrating previously reported markers and 11 newly developed PCR markers improves allelic identification of the Glu-B1 locus and facilitates more effective analysis of Glu-B1 alleles molecular variations, which may improve the end-use quality of wheat. [ABSTRACT FROM AUTHOR]

Background: Flowering time has an important effect on regional adaptation and yields for crops. The tyrosine kinase-like (TKL) gene family is widely existed and participates in many biological processes in plants. Furthermore, only few TKLs have been characterized functions in controlling flowering time in wheat. Results: Here, we report that TaCTR1, a tyrosine kinase-like (TKL) gene, regulates flowering time in wheat. Based on identification and evolutionary analysis of TKL_CTR1-DRK-2 subfamily in 15 plants, we proposed an evolutionary model for TaCTR1, suggesting that occurrence of some exon fusion events during evolution. The overexpression of TaCTR1 caused early flowering time in transgenic lines. Transcriptomics analysis enabled identification of mass differential expression genes including plant hormone (ET, ABA, IAA, BR) signaling, flavonoid biosynthesis, phenolamides and antioxidant, and flowering-related genes in TaCTR1 overexpression transgenic lines compared with WT plants. qRT–PCR results showed that the expression levels of ethylene (ET) signal-related genes (ETR, EIN, ERF) and flowering-related genes (FT, PPD1, CO, PRR, PHY) were altered in TaCTR1-overexpressing wheat compared with WT plants. Metabonomics analysis showed that flavonoid contents were altered. Conclusions: Thus, the results show that TaCTR1 plays a positive role in controlling flowering time by activating various signaling pathways and regulating flowering-related genes, and will provide new insights on the mechanisms of wheat flowering regulation. [ABSTRACT FROM AUTHOR]

This study aimed to assess the nutritional status of soybean and wheat and the relationship with grain yield and biometric components after lime and phosphogypsum (GY) reapplication. Treatments consisted of two lime application methods, surface liming and incorporated liming, to different levels of base saturation (BS) (44, 70, and 90%), in addition to surface liming to 70% BS associated with a standard dose (70GY1) or double dose (70GY2) of GY. Treatments were applied in 2012 and reapplied in 2016. The results refer to the 2018/2019 soybean season and the 2019 wheat season. Lime + GY treatment increased leaf area, plant height, leaf dry matter, and stem dry matter in soybean but had no effect on specific leaf area (235.4 cm2 g−1), stem diameter (6.08 mm), number of pods per plant (71.7), grain number per plant (165), or thousand grain weight (117 g). Liming to 90% BS reduced leaf manganese contents in both crops and leaf iron content in soybean. GY application improved the calcium status of both crops and the sulfur status of soybean. However, 70GY2 reduced leaf magnesium contents in soybean and wheat. Soil tillage without lime reduced wheat yield by 12% compared with no-till. Soybean yield correlated positively with leaf nitrogen (0.79), leaf phosphorus (0.91), leaf area (0.62), and thousand grain weight (0.65), whereas wheat yield correlated with leaf phosphorus (0.83), calcium (0.75), and sulfur (0.74). For improved soybean and wheat performance, it is preferable to apply lime and GY to the soil surface (70GY1), permanently maintaining no-till practices. [ABSTRACT FROM AUTHOR]

Fungal diseases cause significant yield loss to wheat production. Septoria tritici blotch (STB), caused by the ascomycete fungus Zymoseptoria trtici, is one of the major fungal diseases affecting wheat production worldwide. In Ethiopia, STB is a severe problem that causes significant yield loss in high and mid‐altitude wheat‐growing areas. The use of resistant varieties is one of the sustainable disease management strategies, particularly for resource‐poor farmers in developing countries. Two hundred and fifty bread wheat genotypes were evaluated to identify septoria tritici resistant genotypes and estimate the extent of genetic variability for resistance to STB and other economically important traits using alpha lattice design under natural infestation in two STB hotspot environments. Analysis of variance revealed highly significant differences among genotypes, environment, and genotype × environment interaction for all traits measured. The genetic coefficient of variance was lower than the phenotypic coefficient of variance for all traits studied, and both test environments showed the influence of the environment on trait expression. High and moderate heritability values were observed for the septoria disease severity parameters, indicating that the STB resistance trait was less influenced by the environment. The days to heading and plant height were inversely correlated with disease severity. This suggests that genotypes with tall plant height and long maturity period could be resistant to septoria tritici blotch through escape mechanisms. Four of the genotypes, namely, G‐215, G‐255, G‐257, and G‐258, were found to be resistant across all locations. These and other promising genotypes will be used in future breeding programmes to select or develop high‐yielding and STB‐resistant bread wheat genotypes that can be deployed in septoria tritici blotch‐prone areas. Highly susceptible genotypes will also be used as controls for STB resistance breeding programmes. [ABSTRACT FROM AUTHOR]

This study evaluated the efficacy of phytogenic silver and zinc nanoparticles in improving heat resilience in various wheat varieties. The silver and zinc nanoparticles were synthesized using plant leaf extract and characterized using various techniques. Four wheat varieties (DBW187, Black Wheat, DBW 50, and PBW 621) were subjected to field trials. The random block design was used, and nanoparticles in different concentrations were applied at various growth stages and morphologically, and yield parameters were recorded. UV–vis spectroscopy spectral analysis showed peaks for Ag nanoparticles at 420 nm wavelength and Zn nanoparticles at 240 and 350 nm wavelength, depicting the preliminary confirmation of nanoparticle synthesis. Electron microscopic analysis (TEM and SEM) provided morphological insights and confirmed synthesis of fine-sized particle mostly in a range between 10 and 60 nm. Energy dispersive x-ray analysis confirmed the elemental composition of the synthesized nanoparticles, with Ag and Zn elements detected in their respective samples. It also confirmed the oxide nature of synthesized ZnNPs. Dynamic light scattering analysis provided size distribution profiles, indicating average sizes of approximately 61.8 nm for Ag nanoparticles and 46.5 nm for Zn nanoparticles. The concentrations of Ag and Zn nanoparticles in the samples were found to be 196.3 ppm and 115.14 ppm, respectively, through atomic absorption spectroscopic analysis. Fourier transform infrared spectroscopy analysis revealed characteristic functional groups present in the nanoparticles. The results of field experiments established that Ag nanoparticles at 75 ppm concentration exhibited the most significant enhancements in plant growth. Conversely, Zn nanoparticles at a 100 ppm concentration demonstrated the most substantial improvements in the growth and yield of heat-stressed wheat varieties. The study concludes that optimized concentrations of silver and zinc nanoparticles can effectively improve heat stress resilience in wheat. These findings are promising to enhance abiotic stress resilience in crops. [ABSTRACT FROM AUTHOR]

AbstractThe number of food safety issues linked to wheat milled products have increased in the past decade. These incidents were mainly caused by the contamination of wheat-based products by enteric pathogens. This manuscript is the first of a two-part review on the status of the food safety of wheat-based products. This manuscript focused on reviewing the available information on the potential pre-harvest and post-harvest sources of microbial contamination, and potential foodborne pathogens present in wheat-based products. Potential pre-harvest sources of microbial contamination in wheat included animal activity, water, soil, and manure. Improper grain storage practices, pest activity, and improperly cleaned and sanitized equipment are potential sources of post-harvest microbial contamination for wheat-based foods. Raw wheat flour products and flour-based products are potentially contaminated with enteric pathogens such as Shiga toxin-producing E. coli (STECs), and Salmonella at low concentrations. Wheat grains and their derived products (i.e., flours) are potential vehicles for foodborne illness in humans due to the presence of enteric pathogens. A more holistic approach is needed for assuring the food safety of wheat-based products in the farm-to-table continuum. Future developments in the wheat supply chain should also be aimed at addressing this emerging food safety threat. [ABSTRACT FROM AUTHOR]

Background: Semi-dwarfing alleles are used widely in cereals to confer improved lodging resistance and assimilate partitioning. The most widely deployed semi-dwarfing alleles in rice and barley encode the gibberellin (GA)-biosynthetic enzyme GA 20-OXIDASE2 (GA20OX2). The hexaploid wheat genome carries three homoeologous copies of GA20OX2, and because of functional redundancy, loss-of-function alleles of a single homoeologue would not be selected in wheat breeding programmes. Instead, approximately 70% of wheat cultivars carry gain-of-function mutations in REDUCED HEIGHT 1 (RHT1) genes that encode negative growth regulators and are degraded in response to GA. Semi-dwarf Rht-B1b or Rht-D1b alleles encode proteins that are insensitive to GA-mediated degradation. However, because RHT1 is expressed ubiquitously these alleles have pleiotropic effects that confer undesirable traits in some environments. Results: We have applied reverse genetics to combine loss-of-function alleles in all three homoeologues of wheat GA20OX2 and its paralogue GA20OX1 and evaluated their performance in three years of field trials. ga20ox1 mutants exhibited a mild height reduction (approximately 3%) suggesting GA20OX1 plays a minor role in stem elongation in wheat. ga20ox2 mutants have reduced GA1 content and are 12–32% shorter than their wild-type segregants, comparable to the effect of the Rht-D1b 'Green Revolution' allele. The ga20ox2 mutants showed no significant negative effects on yield components in the spring wheat variety 'Cadenza'. Conclusions: Our study demonstrates that chemical mutagenesis can expand genetic variation in polyploid crops to uncover novel alleles despite the difficulty in identifying appropriate mutations for some target genes and the negative effects of background mutations. Field experiments demonstrate that mutations in GA20OX2 reduce height in wheat, but it will be necessary to evaluate the effect of these alleles in different genetic backgrounds and environments to determine their value in wheat breeding as alternative semi-dwarfing alleles. [ABSTRACT FROM AUTHOR]