Wheat Breeding Research Articles

Drought Resistance in Wheat (Triticum aestivum L)

Wheat is a grain crop that is farmed all over the world for bread, chapati, and biscuits. Specific wheat breeding and quality development projects that result in high-yielding, genetically superior, disease resistant varieties of desirable quality that are adaptive to growing conditions. Drought is one of the most important factors affecting crop productivity and yield. Drought stress has a variety of effects on crops, including molecular, physiological, biochemical responses and morphological. Wheat has numerous genes that control drought tolerance and produce a variety of proteins and enzymes, including Responsive to abscisic acid (Rab), late embryogenesis abundant (lea), proline, ligase, rubisco, carbohydrates and antioxidant enzyme (GST). The influence of water shortage on the morphological, biochemical, molecular and physiological responses of wheat to possible drought stress losses was the subject of this review research. Drought is a state in which soil moisture is decreased, resulting in a variety of agricultural changes. Drought reduces crop yield and leads to crop failure. It has an impact on morphology, agricultural productivity and other factors. The vegetative, reproductive which are essential growth stages are affected. Some plants have mechanism to tolerate those conditions. Nearly 50% of the crop production has decreased due to droughts. The various approaches like Quantitative trait locus (QTL) are employed for drought tolerance. Punjab produces 125 metric tonnes of wheat (in lakh metric tonnes), Madhya Pradesh(113.38MT), Haryana (70.65 MT) and Uttar Pradesh (70.65 MT) are the averages (20.39MT) whereas Rajasthan (10.63 MT). The review gives details on latest innovations for the development of resistant genotypes.

Genotype-Specific Activation of Autophagy during Heat Wave in Wheat.

Recycling of unnecessary or dysfunctional cellular structures through autophagy plays a critical role in cellular homeostasis and environmental resilience. Therefore, the autophagy trait may have been unintentionally selected in wheat breeding programs for higher yields in arid climates. This hypothesis was tested by measuring the response of three common autophagy markers, ATG7, ATG8, and NBR1, to a heat wave under reduced soil moisture content in 16 genetically diverse spring wheat landraces originating from different geographical locations. We observed in the greenhouse trials that ATG8 and NBR1 exhibited genotype-specific responses to a 1 h, 40 °C heat wave, while ATG7 did not show a consistent response. Three genotypes from Uruguay, Mozambique, and Afghanistan showed a pattern consistent with higher autophagic activity: decreased or stable abundance of both ATG8 and NBR1 proteins, coupled with increased transcription of ATG8 and NBR1. In contrast, three genotypes from Pakistan, Ethiopia, and Egypt exhibited elevated ATG8 protein levels alongside reduced or unaltered ATG8 transcript levels, indicating a potential suppression or no change in autophagic activity. Principal component analysis demonstrated a correlation between lower abundance of ATG8 and NBR1 proteins and higher yield in the field trials. We found that (i) the combination of heat and drought activated autophagy only in several genotypes, suggesting that despite being a resilience mechanism, autophagy is a heat-sensitive process; (ii) higher autophagic activity correlates positively with greater yield; (iii) the lack of autophagic activity in some high-yielding genotypes suggests contribution of alternative stress-resilient mechanisms; and (iv) enhanced autophagic activity in response to heat and drought was independently selected by wheat breeding programs in different geographic locations.

The addition of Psathyrostachys Huashanica Keng 6Ns large segment chromosomes has positive impact on stripe rust resistance and plant spikelet number of common wheat

BackgroundDeveloping novel germplasm by using wheat wild related species is an effective way to rebuild the wheat resource bank. The Psathyrostachys huashanica Keng (P. huashanica, 2n = 2x = 14, NsNs) is regarded as a superior species to improve wheat breeding because of its multi-resistance, early maturation and numerous tiller traits. Introducing genetic components of P. huashanica into the common wheat background is the most important step in achieving the effective use. Therefore, the cytogenetic characterization and influence of the introgressed P. huashanica large segment chromosomes in the wheat background is necessary to be explored.ResultsIn this study, we characterized a novel derived line, named D88-2a, a progeny of the former characterized wheat-P. huashanica partial amphiploid line H8911 (2n = 7x = 49, AABBDDNs). Cytological identification showed that the chromosomal composition of D88-2a was 2n = 44 = 22II, indicating the addition of exogenous chromosomes. Genomic in situ hybridization demonstrated that the supernumerary chromosomes were a pair of homologues from the P. huashanica and could be stably inherited in the common wheat background. Molecular markers and 15 K SNP array indicated that the additional chromosomes were derived from the sixth homoeologous group (i.e., 6Ns) of P. huashanica. Based on the distribution of the heterozygous single-nucleotide polymorphism sites and fluorescence in situ hybridization karyotype of each chromosome, this pair of additional chromosomes was confirmed as P. huashanica 6Ns large segment chromosomes, which contained the entire short arm and the proximal centromere portion of the long arm. In terms of the agronomic traits, the addition line D88-2a exhibited enhanced stripe rust resistance, improved spike characteristics and increased protein content than its wheat parent line 7182.ConclusionsThe new wheat germplasm D88-2a is a novel cytogenetically stable wheat-P. huashanica 6Ns large segment addition line, and the introgressed large segment alien chromosome has positive impact on plant spikelet number and stripe rust resistance. Thus, this germplasm can be used for genetic improvement of cultivated wheat and the study of functional alien chromosome segment.

GLUTENIN DIVERSITY OF FLOUR WHEAT (Triticum aestivum L.) FOR COOKIE QUALITY IN MEXICO

Glutenins are high- and low-molecular-weight proteins (HMW-G and LMW-G). They play a determining role in genetic improvement to define industrial quality in flour wheat, so understanding their variability is necessary for directing selection toward a specific quality. The objective of this research was to determine the diversity of HMW-G and LMW-G alleles of genotypes from the flour wheat breeding program of the National Institute of Forestry, Agricultural, and Livestock Research (INIFAP) useful for cookie quality. Twenty-five genotypes were used, including six Mexican cookie varieties, as well as 21 genotypes introduced from an international collection of accessions from the International Maize and Wheat Improvement Center (CIMMYT). HMW-G and LMW-G were identified based on their separation on polyacrylamide gels in the presence of sodium dodecyl sulfate. For HMW-G, the 2* variant in Glu-A1 was the most frequent variant for the trial and introduction nursery, with more than 80 %. At the Glu-B1 locus, the 7+9 and 7 variants were the most frequent, with 60 and 38.1 % in trial and nursery, respectively. For Glu-D1, the 2+12 variant was the most frequent in the trial with 64 %, and 5+10 with 85.7 % in nursery. The latter allele favors baking quality. For the Glu-A1 and Glu-D1 loci, it is necessary to introduce genotypes with null alleles or with the 2+121 variant in Glu-D1 associated with cookie quality. For the highest-frequency variants of LMW-G, c in Glu-A3, h in Glu-B3, and b in Glu-D3 are associated with baking quality. With the aforementioned, it is concluded that there is a low frequency and little variation in useful alleles of HMW-G and LMW-G for cookie quality in the introduced accessions analyzed, implying that new genetic sources that favor it should be explored.

Wheat breeding strategies for increased climate resilience

Wheat breeding strategies for increased climate resilience

Discovering novel genomic regions explaining adaptation of bread wheat to conservation agriculture through GWAS

To sustainably increase wheat yield to meet the growing world population’s food demand in the face of climate change, Conservation Agriculture (CA) is a promising approach. Still, there is a lack of genomic studies investigating the genetic basis of crop adaptation to CA. To dissect the genetic architecture of 19 morpho-physiological traits that could be involved in the enhanced adaptation and performance of genotypes under CA, we performed GWAS to identify MTAs under four contrasting production regimes viz., conventional tillage timely sown (CTTS), conservation agriculture timely sown (CATS), conventional tillage late sown (CTLS) and conservation agriculture late sown (CALS) using an association panel of 183 advanced wheat breeding lines along with 5 checks. Traits like Phi2 (Quantum yield of photosystem II; CATS:0.37, CALS: 0.31), RC (Relative chlorophyll content; CATS:55.51, CALS: 54.47) and PS1 (Active photosystem I centers; CATS:2.45, CALS: 2.23) have higher mean values in CA compared to CT under both sowing times. GWAS identified 80 MTAs for the studied traits across four production environments. The phenotypic variation explained (PVE) by these QTNs ranged from 2.15 to 40.22%. Gene annotation provided highly informative SNPs associated with Phi2, NPQ (Quantum yield of non-photochemical quenching), PS1, and RC which were linked with genes that play crucial roles in the physiological adaptation under both CA and CT. A highly significant SNP AX94651261 (9.43% PVE) was identified to be associated with Phi2, while two SNP markers AX94730536 (30.90% PVE) and AX94683305 (16.99% PVE) were associated with NPQ. Identified QTNs upon validation can be used in marker-assisted breeding programs to develop CA adaptive genotypes.

Phenotypic characterization and gene mapping of hybrid necrosis in Triticum durum–Haynaldia villosa amphiploids

Key messagePhenotypical, physiological and genetic characterization was carried out on the hybrid necrosis gene from Haynaldia villosa, and the related gene Ne-V was mapped to chromosome arm 2VL.Introducing genetic variation from wild relatives into common wheat through wide crosses is a vital strategy for enriching genetic diversity and promoting wheat breeding. However, hybrid necrosis, a genetic autoimmunity syndrome, often occurs in the offspring of interspecific or intraspecific crosses, restricting both the selection of hybrid parents and the pyramiding of beneficial genes. To utilize the germplasms of Haynaldia villosa (2n = 2x = 14, VV), we conducted wide hybridization between durum wheat (2n = 4x = 28, AABB) and multiple H. villosa accessions to synthesize the amphiploids (2n = 6x = 42, AABBVV). This study revealed that 61.5% of amphiploids derived from the above crosses exhibited hybrid necrosis, with some amphiploids even dying before reaching maturity. However, the initiation time and severity of necrosis varied dramatically among the progenies, suggesting that there were multiple genetic loci or multiple alleles in the same genetic locus conferring to hybrid necrosis in H. villosa accessions. Genetic analysis was performed on the F2 and derived F2:3 populations, which were constructed between amphiploid STH59-1 with normal leaves and amphiploid STH59-2 with necrotic leaves. A semidominant hybrid necrosis-related gene, Ne-V, was mapped to an 11.8-cM genetic interval on the long arm of chromosome 2V, representing a novel genetic locus identified in Triticum-related species. In addition, the hybrid necrosis was correlated with enhanced H2O2 accumulation and cell death, and it was influenced by the temperature and light. Our findings provide a foundation for cloning the Ne-V gene and exploring its molecular mechanism.

TaMIR397-6A and -6B Homoeologs Encode Active miR397 Contributing to the Regulation of Grain Size in Hexaploid Wheat.

Wheat is one of the most important food crops globally, and understanding the regulation of grain size is crucial for wheat breeding to achieve a higher grain yield. MicroRNAs (miRNAs) play vital roles in plant growth and development. However, the miRNA-mediated mechanism underlying grain size regulation remains largely elusive in wheat. Here, we report the characterization and functional validation of a miRNA, TamiR397a, associated with grain size regulation in wheat. The function of three TaMIR397 homoeologs was determined through histochemical β-glucuronidase-dependent assay. MiRNA expression was detected using quantitative reverse transcription polymerase chain reaction (qRT-PCR), and the function of TamiR397a was validated through its transgenic overexpression and repression in wheat. It was found that TaMIR397-6A and TaMIR397-6B encode active TamiR397a. The expression profiling indicated that TamiR397a was differentially expressed in various tissues and gradually up-regulated during grain filling. The inhibition of TamiR397a perturbed grain development, leading to a decrease in grain size and weight. Conversely, the overexpression of TamiR397a resulted in increased grain size and weight by accelerating the grain filling process. Transcriptome analysis revealed that TamiR397a regulates a set of genes involved in hormone response, desiccation tolerance, regulation of cellular senescence, seed dormancy, and seed maturation biological processes, which are important for grain development. Among the down-regulated genes in the grains of the TamiR397a-overexpressing transgenic plants, 11 putative targets of the miRNA were identified. Taken together, our results demonstrate that TamiR397a is a positive regulator of grain size and weight, offering potential targets for breeding wheat with an increased grain yield.

Molecular characterization and evaluation of different irrigation regimens on yield and other agronomic traits of some Egyptian wheat cultivars

ABSTRACT The objective of this study was to determine the optimal irrigation needs of six popular Egyptian bread wheat (Triticum aestivum L.) cultivars and to establish baseline effect of reduced irrigation on yield. The varieties included were Sids1, Sids14, Sakha94, Sakha95, Gemmiza12, and Shandawee1. The experiment was conducted at two different locations, Nubaria and Sids Agricultural Research Stations, Egypt over two consecutive seasons, 2020–2021 and 2021–2022. There was a reduction in yield with the decrease in the number of irrigations. However, several cultivars performed better for yield and other traits with one less irrigation than the current irrigation practices in the region. Therefore, the study may help revise irrigation recommendations. Overall, the cultivars Sakha95, Sids1, and Sids14 were taller and had more kernels per spike, higher seed index, and greater grain yield under reduced irrigations and showed the best drought tolerance index. The tested bread wheat cultivars were genotyped using Inter-Retrotransposon Amplified Polymorphism (IRAP) and Start Codon Targeted (SCoT) markers which showed relation among the cultivars. Among the two types of markers, IRAP was better than SCoT markers for reliability and robustness. Among the six cultivars, 58% of the IRAP markers detected polymorphism as compared to 38% with SCoT markers. The two wheat cultivars Sids1 and Sids14, which performed better for important agronomic traits under water stress conditions, could be used as donors for the national wheat breeding program for drought tolerance.

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

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

Breeding and genetic improvement of spelt wheat (Triticum spelta) by interspecific hybridization

Spelt wheat (Triticum spelta L.) is a high-value grain crop which is characterized by high protein, gluten and aminoacids content, high adaptive potential, resistance to diseases and high antioxidant activity. However, it is significantly inferior to soft wheat in terms of yield capacity. From crosses of spelt and soft wheat new promising genotypes can be obtained with improved quantitative traits due to introgression in the genome of spelt wheat of genetic material of soft wheat. In the research presented here based on hybridization of Triticum spelta L. × Triticum aestivum L. we obtained new forms of spelt which differ among themselves in terms of morphological characteristics, productivity and grain quality. As a result of the conducted research, a wide form-forming process in terms of plant height, ear morphology and grain threshing quality was recorded. The height of plants in F1 hybrids is inherited by the type of dominance of high stemness or intermediate inheritance was established. In the F2–F4 generations, the share of obtaining short-stemmed forms of spelt wheat was higher than with the use of short-stemmed varieties of common wheat as the maternal form. In F2 offspring, the inheritance of threshing quality by the type of dominant epistasis according to the 12 : 3 : 1 scheme was established. In F3–4 offspring, splitting according to ear morphology occurred with the appearance of not only typical forms of spelt wheat or common wheat, but also intermediate forms with different ratios of spike length and density. High-yielding (5.75–5.79 t/ha) short-stemmed (h = 78–89 cm) spelt wheat samples 1817 and 1559 with high grain quality indicators (weight of 1000 grains 64.4 g, protein content – 21.0%, gluten – 43.7%) were identified. Sample 13, which successfully combined high grain quality indicators in particular high protein content (26.2%), gluten content (55.8%), grain hardness (66.5 units), flour strength (340 alveograph units) was selected.

First Report of Pantoea ananatis causing leaf streak disease on wheat (Triticum aestivum) in the United States of America.

Wheat (Triticum aestivum) loses 21.5% yield to pests and diseases annually (Savary et al. 2019). Among the wheat diseases, bacterial leaf streak (BLS) is a growing problem, costing $78.5 million in losses (https://cropprotectionnetwork.org/). In July 2022, we sampled winter wheat leaf samples at Volga (44.30, -96.92), South Dakota, USA with an estimated disease incidence of 40% (n=100). The typical symptoms were water-soaking with large necrotic and chlorotic streaks extending the length of the leaves and were strikingly similar to BLS. To isolate the pathogen, leaves were cut lengthwise into 1 cm pieces and surface-sterilized using a 10% NaOCl solution for 3 min, followed by 70% ethanol for 3 min, and then rinsed with sterile distilled water and placed in 500 ul of sterile distilled water for 5 min and using a sterile loop the water was streaked over a plate of Nutrient Agar (NA). Following Duveiller et al. (1997), the streaked plate was incubated in the dark at 28℃ for 48 h. Observed single colonies were sub-cultured thrice onto fresh NA plates to obtain a pure culture. We named the culture SD101. Bacteria were found to be gram-negative with a colony morphology initially raised, smooth, and white that later turned yellow. DNA was extracted using the Wizard HMW DNA Extraction Kit (Promega, Madison, WI) following the manufacturer's protocol, and sequenced using Nanopore MinION R9.4 (Oxford Nanopore Technology). We used the Rapid Annotation Using Subsystems Technology approach (Aziz eal. 2008) to extract the 16S rDNA, DNA gyrase subunit B (gyrB), and translation initiation factor IF-2 (infB) gene sequences that were deposited in GenBank under accession numbers PP329908.1 for 16S rDNA, PP496481 for infB, and PP328920.1 for gyrB. Homology analysis using CLC Genomics Workbench 22.0.2 (QIAGEN) and BLASTn against the GenBank nucleotide database resulted in a 99.74% match (1543/ 1547 bp) of the 16S sequence, 99.59% match (2674/ 2685 bp) of the infB sequence, and 99.42% match (2396/ 2410 bp) of the gyrB sequence with Pantoea ananatis strain AJ13355 (AP012032). To test pathogenicity, seeds of spring wheat breeding line SD4892 were planted in 30 cm × 30 cm pots in a greenhouse under a 16 h light photoperiod. The inoculum was prepared from 48-h-old NA plates of SD101 rinsed with 1X Phosphate Buffer Saline (PBS buffer), adjusted to an OD600 = 1.0, and amended with two drops of Tween 20 (polyoxyethylene sorbitol ester, Millipore Sigma). PBS with Tween 20 was used as a negative control. The inoculum was sprayed on 15 replicates of 15-day-old seedlings, kept at 95% relative humidity for 48 h, then moved to the greenhouse at 23 to 25°C. The symptoms appeared as water soaking that later turned to necrotic streaks with surrounding chlorosis on all 15 inoculated plants while control plants remained healthy. The pathogen was re-isolated from the leaves as described above. The 16S rDNA, infB, and gyrB sequences amplified and sequenced were identical to the gene sequences from the whole genome sequencing. The experiment was repeated with the same results, completing Koch's postulates. Although P. ananatis is pathogenic on corn, rice, and other plant species in the United States (Coutinho et al. 2009), and was reported pathogenic on wheat in Poland (Krawczyk et al. 2020), this is the first report of its pathogenicity on wheat in the United States. The prevalence, and incidence of BLS disease caused by P. ananatis in wheat is needed to estimate its threat to wheat production and to develop management strategies.

Morpho-physiological characterization and selection of heat tolerant wheat lines using selection indices

Heat stress is one of the major constraints in wheat production due to its adverse effect on grain yield and component traits. Moreover, it negatively affects the physiological, biochemical and quality traits of wheat. Therefore, selection of heat tolerant wheat lines is one of the major breeding goals for wheat scientist. In present study, 238 recombinant inbred lines were evaluated along with their parents WH 711 × WH 542 under timely and late sown (heat stress) condition. The heat tolerance indices were calculated based on grain yield under normal and stress conditions. The mean grain yield of 238 wheat lines was reduced by 20.54% suggesting critical effect of heat stress on grain yield. The harmonic mean (HM), stress tolerance index (STI), mean productivity (MP), geometric mean productivity (GMP), and mean relative performance (MRP) were correlated significantly and positively with grain yield under stress and normal conditions. Whereas, Tolerance index (TOL) was correlated negatively with grain yield under stress conditions and positively under normal condition. Based on STI, MP, HM, GMP and MRP, wheat lines WL 92, WL 119, WL 114, WL 110, WL 6 were identified as heat tolerant and could be utilized as potential lines for increasing heat stress tolerance of future wheat breeding programs.

Screening of CIMMYT and South Asian Bread Wheat Germplasm Reveals Marker-Trait Associations for Seedling Resistance to Septoria Nodorum Blotch.

Wheat (Triticum aestivum L.) production is adversely impacted by Septoria nodorum blotch (SNB), a fungal disease caused by Parastagonospora nodorum. Wheat breeders are constantly up against this biotic challenge as they try to create resistant cultivars. The genome-wide association study (GWAS) has become an efficient tool for identifying molecular markers linked with SNB resistance. This technique is used to acquire an understanding of the genetic basis of resistance and to facilitate marker-assisted selection. In the current study, a total of 174 bread wheat accessions from South Asia and CIMMYT were assessed for SNB reactions at the seedling stage in three greenhouse experiments at CIMMYT, Mexico. The results indicated that 129 genotypes were resistant to SNB, 39 were moderately resistant, and only 6 were moderately susceptible. The Genotyping Illumina Infinium 15K Bead Chip was used, and 11,184 SNP markers were utilized to identify marker-trait associations (MTAs) after filtering. Multiple tests confirmed the existence of significant MTAs on chromosomes 5B, 5A, and 3D, and the ones at Tsn1 on 5B were the most stable and conferred the highest phenotypic variation. The resistant genotypes identified in this study could be cultivated in South Asian countries as a preventative measure against the spread of SNB. This work also identified molecular markers of SNB resistance that could be used in future wheat breeding projects.

Transferring an Adult-Plant Stripe-Rust Resistance Gene Yr7VS from Chromosome 7V of Dasypyrum villosum (L.) to Bread Wheat.

Stripe rust (Puccinia striiformis West. f.sp. tritici, Pst) is a destructive disease that seriously threatens wheat production globally. Exploring novel resistance genes for use in wheat breeding is an urgent need, as continuous Pst evolution frequently leads to a breakdown of host resistance. Here, we identified a set of wheat-Dasypyrum villosum 01I139 (V#6) disomic introgression lines for the purpose of determining their responses to a mixture of Pst isolates CYR32, CYR33 and CYR34 at both seedling and adult-plant stages. The results showed that all introgression lines exhibited high susceptibility at the seedling stage, with infection-type (IT) scores in the range of 6-8, whereas, for chromosomes 5V#6 and 7V#6, disomic addition lines NAU5V#6-1 and NAU7V#6-1 displayed high resistance at the adult-plant stage, indicating that adult-plant resistance (APR) genes were located on them. Further, in order to transfer the stripe-rust resistance on chromosome 7V#6, four new wheat-D. villosum introgression lines were identified, by the use of molecular cytogenetic approaches, from the self-pollinated seeds of 7D and 7V#6, in double monosomic line NAU7V#6-2. Among them, NAU7V#6-3 and NAU7V#6-4 were t7V#6L and t7V#6S monosomic addition lines, and NAU7V#6-5 and NAU7V#6-6 were homozygous T7DS·7V#6L and T7DL·7V#6S whole-arm translocation lines. Stripe-rust tests and genetic analyses of chromosome 7V#6 introgression lines revealed a dominant APR gene designated as Yr7VS on the chromosome arm 7V#6S. Comparison with the homozygous T7DL·7V#6S translocation line and the recurrent parent NAU0686 showed no significant differences in yield-related traits. Thus, T7DL·7V#6S whole-arm translocation with the APR gene Yr7VS provided a valuable germplasm for breeding for resistance.

GWAS elucidated grain yield genetics in Indian spring wheat under diverse water conditions.

Underpinned natural variations and key genes associated with yield under different water regimes, and identified genomic signatures of genetic gain in the Indian wheat breeding program. A novel KASP marker for TKW under water stress was developed and validated. A comprehensive genome-wide association study was conducted on 300 spring wheat genotypes to elucidate the natural variations associated with grain yield and its eleven contributing traits under fully irrigated, restricted water, and simulated no water conditions. Utilizing the 35K Wheat Breeders' Array, we identified 1155 quantitative trait nucleotides (QTNs), with 207 QTNs exhibiting stability across diverse conditions. These QTNs were further delimited into 539 genomic regions using a genome-wide LD value of 3.0Mbp, revealing pleiotropic control across traits and conditions. Sub-genome A was significantly associated with traits under irrigated conditions, while sub-genome B showed more QTNs under water stressed conditions. Favourable alleles with significantly associated QTNs were delineated, with a notable pyramiding effect for enhancing trait performance. Additionally, allele of only 921 QTNs significantly affected the population mean. Allele profiling highlighted C-306 as a most potential source of drought tolerance. Moreover, 762 genes overlapping significant QTNs were identified, narrowing down to 27 putative candidate genes overlapping 29 novel and functional SNPs expressing (≥ 0.5tpm) relevance across various growth conditions. A new KASP assay was developed, targeting a gene TraesCS2A03G1123700 regulating thousand kernel weight under severe drought condition. Genomic selection models (GBLUP, BayesB, MxE, and R-Norm) demonstrated an average prediction accuracy of 0.06-0.58 across environments, indicating potential for trait selection. Retrospective analysis of the Indian wheat breeding program supported a genetic gain in GY at the rate of ca. 0.56% per breeding cycle, since 1960, supporting the identification of genomic signatures driving trait selection and genetic gain. These findings offer insight into improving the rate of genetic gain in wheat breeding programs globally.

Applications of Artificial Intelligence in Wheat Breeding for Sustainable Food Security

In agriculture, especially in crop breeding, innovative approaches are required to address the urgent issues posed by climate change and global food security. Artificial intelligence (AI) is a revolutionary technology in wheat breeding that provides new approaches to improve the ability of crops to withstand and produce higher yields in response to changing climate circumstances. This review paper examines the incorporation of artificial intelligence (AI) into conventional wheat breeding methods, with a focus on the contribution of AI in tackling the intricacies of contemporary agriculture. This review aims to assess the influence of AI technologies on enhancing the efficiency, precision, and sustainability of wheat breeding projects. We conduct a thorough analysis of recent research to evaluate several applications of artificial intelligence, such as machine learning (ML), deep learning (DL), and genomic selection (GS). These technologies expedite the swift analysis and interpretation of extensive datasets, augmenting the process of selecting and breeding wheat varieties that are well-suited to a wide range of environmental circumstances. The findings from the examined research demonstrate notable progress in wheat breeding as a result of artificial intelligence. ML algorithms have enhanced the precision of predicting phenotypic traits, whereas genomic selection has reduced the duration of breeding cycles. Utilizing artificial intelligence, high-throughput phenotyping allows for meticulous examination of plant characteristics under different stress environments, facilitating the identification of robust varieties. Furthermore, AI-driven models have exhibited superior predicted accuracies for crop productivity and disease resistance in comparison to conventional methods. AI technologies play a crucial role in the modernization of wheat breeding, providing significant enhancements in crop performance and adaptability. This integration not only facilitates the growth of wheat cultivars that provide large yields and can withstand stressful conditions but also strengthens global food security in the context of climate change. Ongoing study and collaboration across several fields are crucial to improving and optimizing these AI applications, ultimately enhancing their influence on sustainable agriculture.

Molecular cytogenetic characteristics of new spring bread wheat introgressive lines resistant to stem rust.

Anticipatory wheat breeding for pathogen resistance is key to preventing economically significant crop losses caused by diseases. Recently, the harmfulness of a dangerous wheat disease, stem rust, caused by Puccinia graminis f. sp. tritici, was increased in the main grain-producing regions of the Russian Federation. At the same time, importation of the Ug99 race (TTKSK) is still a possibility. In this regard, the transfer of effective resistance genes from related species to the bread wheat breeding material followed by the chromosomal localization of the introgressions and a marker analysis to identify known resistance genes is of great importance. In this work, a comprehensive analysis of ten spring bread wheat introgressive lines of the Federal Center of Agricultural Research of the South-East Region (L657, L664, L758, L935, L960, L968, L971, L995/1, L997 and L1110) was carried out. These lines were obtained with the participation of Triticum dicoccum, T. timopheevii, T. kiharae, Aegilops speltoides, Agropyron elongatum and Secale cereale. In this study, the lines were evaluated for resistance to the Ug99 race (TTKSK) in the Njoro, Kenya. Evaluation of introgression lines in the field for resistance to the Ug99 race (TTKSK) showed that four lines were immune, two were resistant, three were moderately resistant, and one had an intermediate type of response to infection. By cytogenetic analysis of these lines using fluorescent (FISH) and genomic (GISH) in situ hybridization, introgressions from Ae. speltoides (line L664), T. timopheevii (lines L758, L971, L995/1, L997 and L1110), Thinopyrum ponticum = Ag. elongatum (2n = 70) (L664, L758, L960, L971, L997 and L1110), as well as introgressions from T. dicoccum (L657 and L664), T. kiharae (L960) and S. cereale (L935 and L968) were detected. Molecular markers recommended for marker-oriented breeding were used to identify known resistance genes (Sr2, Sr25, Sr32, Sr1A.1R, Sr36, Sr38, Sr39 and Sr47). The Sr36 and Sr25 genes were observed in lines L997 and L1110, while line L664 had the Sr39+Sr47+Sr25 gene combination. In lines L935 and L968 with 3R(3D) substitution from S. cereale, gene resistance was presumably identified as SrSatu. Thus, highly resistant to both local populations of P. graminis and the Ug99 race, bread wheat lines are promising donors for the production of new varieties resistant to stem rust.

Fine mapping of the powdery mildew resistance gene PmXQ-0508 in bread wheat

In a wheat breeding line XQ-0508 showing consistent resistance to powdery mildew disease, a recessive gene, designated PmXQ-0508, was identified and mapped to a distal region on chromosome arm 2BS. Of three resistance-associated genes in this region, one encoding a protein kinase was selected as the primary candidate for PmXQ-0508. Ten closely linked DNA markers developed in the study could be used for marker-assisted selection for powdery-mildew resistance in breeding programs.

Identification and Characterization of Resistance Loci to Stripe Rust in Winter Wheat Breeding Line YN1813

The development and deployment of diverse resistance sources in novel wheat cultivars underpin the durable control of stripe rust. The objectives of this study were to identify quantitative trait loci (QTL) associated with stripe rust resistance in the Chinese wheat breeding line YN1813 and to provide wheat breeders with original genes with potentially durable resistance. A total of 306 F7:8 recombinant inbred lines (RIL), derived from a cross between YN1813 (infection type 0–3 and disease severity 1–36%) and the moderately susceptible landrace Chinese Spring (IT 7–9 and DS 41–65%), were assessed for stripe rust disease severity in the field at Qingshui in Gansu and Pixian in Sichuan in 2020 and 2021 following inoculation with a mixture of the currently predominant Pst races. The parents and RIL were genotyped using the Wheat 55K single-nucleotide polymorphism (SNP) array. The total length of the constructed genetic linkage map was 3896.30 cm, with an average interval of 1.30 cm between adjacent markers. Two major QTL were identified on chromosome 7B and 7D across all tested environments. QYr.hau-7B was mapped to a 2.26 cm interval between the SNP markers AX-110908486–AX-89658728–AX-109489314 on chromosome 7B, explaining 0.9% to 16.9% of the phenotypic variation. QYr.hau-7D was positioned in a 0.67 cm interval flanked by the SNP markers AX-111654594 and AX-89378255, explaining 0.4% to 21.4% of the phenotypic variation. The QTL on 7D likely correspond to the previously known gene Yr18, whereas QYr.hau-7B was presumed to be a novel gene adjacent to YrZH84 or the core part of YrZH84. SNP markers closely linked with QYr.hau-7B were converted to allele-specific quantitative PCR-based genotyping assay (AQP) markers and validated in a panel of 712 wheat accessions. The group possessing a positive allele (TT) of AQP_AX-89658728 significantly (p < 0.05) decreased the IT by 45.8% and the DS by 63.2%. QYr.hau-7B and its markers could be useful in breeding programs to improve the level and durability of stripe rust resistance.