Genome-Wide Association Study for Yield and Agronomic Traits in Soft Winter Wheat.

Genome-wide association studies (GWAS) are a powerful tool for identifying marker-trait associations (MTA) in order to dissect the genetic architecture underlying crop grain yield (GY) to further genetic gains. A GWAS for GY and agronomic traits was conducted using a diverse panel of 240 soft red winter wheat genotypes evaluated over two growing seasons in eight total site-years. Analyses among measured traits revealed high correlation between GY and its components. Analysis of variance (ANOVA) showed significant environment and genotype effects across all locations. GY was moderately heritable across locations (h² = 0.69) compared to other traits including plant height (PH) (h² = 0.86) and thousand kernel weight (h² = 0.85). A total of 83 significant MTA (p < 0.0005) were detected for all traits using three different compressed mixed linear models and 5,287 single nucleotide polymorphism (SNP) markers. MTA for GY and related traits identified on this study coincide with reported QTL for winter and spring wheat in chromosomes 3A, 5A, 5B, 6A, and 7B. Markers in 1B associated with PH represent novel loci affecting variation for this trait. Pleiotropic MTA observed in chromosomes 1A and 3B could be potential targets of selection for marker assisted breeding to select for variation in GY, yield components, and agronomic traits following proper marker validation. Over-all, results demonstrated the utility of association mapping approaches in determining genomic regions affecting variation for traits of agricultural and economic importance.