Genome wide association mapping for drought tolerance in bread wheat Triticum aestivum L

Abstract

Global climate change poses a significant threat to wheat productivity, with drought stress being particularly newlinechallenging and impeding crop production. In wheat cultivation, terminal drought during anthesis is a key newlineconcern, leading to further reductions in yield. Thus, it is important to identify wheat genetic resources with newlinedrought tolerance and high genetic yield potential. In the present investigation, three hundred and six diverse newlinewheat genotypes including well characterized doubled haploids, potential landraces, elite exotic lines and newlinepopular Indian cultivars were tested under five different optimal and water stressed environments using newline17×18 alpha lattice design with three replications across the North Western Himalayas. The genetic newlinearchitecture of drought resilience was dissected employing ddRAD based GWAS approach. Perusal of the newlineANOVA revealed substantial variability and significant differences among genotypes for all the studied newlinetraits pooled over environments under both the conditions, indicating that these traits were significantly newlineaffected by drought stress. Under drought stress, the grain filling period was significantly shorter, and the newlineaverage grain yield reduced to 2.81 t/ha compared to 4.28 t/ha under optimal conditions across different newlineenvironments. Grain yield per plant showed significant positive correlation with flag leaf length, tillers per newlineplant, spikelets per spike, grains per spike, thousand-grain weight, biological yield, harvest index, drought newlinetolerance efficiency and proline content while, days to anthesis, days to maturity, grain filling period, drought newlinesusceptibility index and root fresh weight were negatively correlated with grain yield per plant. Under rainfed newlineconditions, four genotypes viz., L 36, L 39, L 44 and L 81 sustained higher grain yields. The dual resistance newlinetowards stripe rust and powdery mildew under natural epiphytotic conditions was displayed by twenty newlinegenotypes across all locations. Genome-wide, 62,156 SNPs were identified, and after filtration w