Mapping Some Seed Quality Traits in Bread Wheat (Triticum aestivum L.) by Association Mapping Using SSR Markers

Quality characteristics including grain protein content, gluten, falling number, and SDS sedimentation volume are important contributors to the grain yield and quality of the wheat. To identify the markers associated with such traits, this study run in two separated experiments: under-field and in laboratory. One hundred wheat genotypes were evaluated in an alpha lattice design with two replications. Association mapping using Structure and Tassel software was carried out using 102 SSR markers: 66 unlinked and 36 quantitative trait loci (QTL)-linked SSR markers. Correction for population structure was performed using genome-wide SSR markers so that genotypes were divided into six subpopulations. Thoroughly, 34 SSR markers linked with the above-mentioned traits were identified, twelve of them being QTL-linked markers. These markers were already mapped on the wheat chromosomes in previous studies containing known QTLs controlling kernel traits of the wheat. Our results confirmed 5, 3, 2, and 2 QTLs respectively for the grain protein, gluten, falling number, and SDS sedimentation volume which were previously tagged on the wheat chromosomes. Additionally, 3 QTLs were identified for the grain protein on the chromosomes 2A, 5A, 5D, and 7B. Whereas, 6 QTLs for gluten were detected on chromosomes 1A, 2D, 5A, 5B, 6B, and 7B; four QTLs were located on the chromosomes 2D, 5A, 5B, 5D, and 7D for falling number; and finally nine QTLs were found for SDS sedimentation volume on the chromosomes 1A, 1B, 2B, 3A, 3B, 4B, 6A, 6B, 7A, and 7B. The results of this study indicated that association mapping is a useful method for detecting and complementing QTL information; thus, this information can be used for further wheat improvement based on a molecular marker.