SNP markers associated with agronomic traits under drought and heat stress in wheat

Drought and heat stresses present significant challenges in agriculture production. This study evaluated CIMMYT-Mexico Core Germplasm (CIMCOG) under drought, heat, and their combined stress over two growing seasons. The germplasm was genotyped with a 35K Axiom® Array to identify associations with the studied traits under these environmental conditions. The Best Linear Unbiased Predictors (BLUPs) of each line were used to calculate marker-trait associations using 16063 SNP markers with a mixed linear model (MLM). For genome-wide association mapping (GWAM), the highest number of associations was obtained for test weight (32) followed by grain hardness (17). In the case of grain yield, six SNPs were detected in association with the trait only under heat stress conditions. However, with a P value threshold of <0.001, GWAM detected many significant associations (11, 31, 10, and 10 associations under normal, drought, heat, and combined (drought-heat) stress conditions, respectively) distributed nearly across most wheat chromosomes. All detected associated SNPs explained a minimum of 18% of the variance to a maximum of 35.2%. Among the detected associations, six were common between heat and drought-heat stress conditions. These results may open a new window for breeding programs to improve wheat stress tolerance for abiotic stress tolerance.

SNP markers associated with agronomic traits under drought and heat stress in wheat Keywords:

Abiotic stress tolerance , GWAS , single nucleotide polymorphism , Triticum aestivum