Genome-Wide Association Study in Bread Wheat Identifies Genomic Regions Associated with Grain Yield and Quality under Contrasting Water Availability

Abstract

The objectives of this study were to identify genetic loci in the bread wheat genome that would influence yield stability and quality under water stress, and to identify accessions that can be recommended for cultivation in dry and hot regions. We performed a genome-wide association study (GWAS) using a panel of 232 wheat accessions spanning diverse ecogeographic regions. Plants were evaluated in the Israeli Northern Negev, under two environments: water-limited (D; 250 mm) and well-watered (W; 450 mm) conditions; they were genotyped with ~71,500 SNPs derived from exome capture sequencing. Of the 14 phenotypic traits evaluated, 12 had significantly lower values under D compared to W conditions, while the values for two traits were higher under D. High heritability (H2 = 0.5–0.9) was observed for grain yield, spike weight, number of grains per spike, peduncle length, and plant height. Days to heading and grain yield could be partitioned based on accession origins. GWAS identified 154 marker-trait associations (MTAs) for yield and quality-related traits, 82 under D and 72 under W, and identified potential candidate genes. We identified 24 accessions showing high and/or stable yields under D conditions that can be recommended for cultivation in regions under the threat of global climate change.

A diverse panel of 755 bread wheat accessions harbors untapped genetic diversity in landraces and reveals novel genetic regions conferring powdery mildew resistance

“…markers that detect both presence-absence polymorphisms and nucleotide polymorphisms. The 29,965 markers were distributed across the wheat genome, similar to earlier findings (Liu et al 2017; Alemu et al 2021; Govta et al 2022), with lower coverage of genome D compared to the A and B genomes: 11,684 (39.0%) markers on the A-genome, 13,589 (45.3%) on the B-genome and 4,692 (15.7%) on the D-genome. On average, 1,427 markers were assigned per chromosome, resulting in an average density of one marker each 483 Kbp.…”

Nutritional Genomic Approach for Improving Grain Protein Content in Wheat

“…The contribution of loci on chromosomes 1A, 2A, 2B, 3A, 3B, and 6B for protein content was confirmed in a GWAS study on UK wheat genotypes [ 48 ], whereas genomic regions on chromosome 6A were recently confirmed in a study on Russian spring cultivars [ 18 ]. QTNs for GPC under limited water supply were located on chromosomes 1B, 2A, 2B, and 6B [ 49 ], of which the QTL 6B.7 was co-mapped with the previously cloned gene Gpc-B1 associated with high grain protein [ 20 ]. In total, 16 significant MTAs for GPC on chromosomes 1A, 1B, 1D, 2B, 3B, 4B, 5A, 5B, 5D, 6A, 6B and 7A have been identified in a set of 280 diverse bread wheat genotypes [ 50 ].…”

The role of endophytes and rhizobacteria to combat drought stress in wheat

“…These PGPMs are known to produce various substances that contribute to plant growth, including phytohormones, enzymes, and secondary metabolites that can solubilize nutrients and sequester carbon in the rhizosphere, as shown in Table 2. Consequently, they have promising potential as bioinoculants for sustainable agriculture (Govta et al, 2022) Wheat can grow and be produced even when there isn't much water. But the amount of water wheat needs to grow depends on how far along it is in its growth and on things in the surroundings (Adesina et al, 2020).…”