Genome-wide association mapping: a case study in bread wheat (Triticum aestivum L.)

Association-based trait mapping is an innovative methodology based on linkage disequilibrium. Studies in plants, especially in cereals, are rare. A genome-wide association study of wheat is reported, in which a large number of diversity array technology markers was used to genotype a winter wheat core collection of 96 accessions. The germplasm was structured into two sub-populations. Twenty agronomic traits were measured in field trials conducted over up to eight growing seasons. Association analysis was performed with two different approaches, the general linear model incorporating the Q-matrix only and the mixed linear model including also the kinship-matrix. In total, 385 marker-trait associations significant in both models were detected. The intrachromosomal location of many of these coincided with those of known major genes or quantitative trait loci, but others were detected in regions where no known genes have been located to date. These latter presumptive loci provide opportunities for further wheat improvement, based on a marker approach.