Genome wide association study of grain yield and yield related traits in spring bread wheat (Triticum aestivum L.) under drought and heat conditions in three different locations

Abiotic stress, especially drought and heat, affects cereal yields and wheat production worldwide, more particularly in West and South Asia, North Africa, and sub-Saharan Africa. The present study was carried out on 229 spring bread wheat (Triticum aestivum L.) genotypes from the International Center for Agricultural Research in Dry Areas (ICARDA) to identify the genomic region and marker-trait associations (MTA) responsible for drought and heat tolerance. The study was carried out in three different locations, Merchouch station (Morocco), Sids station (Egypt), and Wadmadani station (Sudan) over a period of 2 years (2018 and 2019). A genome-wide association study (GWAS) was performed using the mixed linear model (MLM) and 13,698 DArTseq markers were used for genotyping. Linkage disequilibrium revealed that 1914 pairs of markers mapped on the B sub- genome, followed by D and A sub-genomes with 1745 and 1726 paired markers, respectively. A total of 342 MTAs (P < 0.05) and 78 genes were identified in the three environments, of which 134 MTAs were recorded at Sids station and 128 and 80 MTAs at Wadmadani station and Merchouch station. The markers 822,842, 196,565 and 753,901 were significantly correlated with grain yield under drought, heat and yield potential stations Morocco, Sudan, and Egypt, respectively. The markers and candidate genes identified in this study have potentials for marker-assisted selection to develop high yielding wheat genotypes with resistance to heat and drought stresses.