Relationship between allelic variation at the Glu-3 loci and qualitative traits in bread wheat

Low molecular weight glutenin subunits (LMW-GS), significantly influence the end-use quality of flour. In this study, a total of 63 Iranian bread wheat were used to evaluate allelic variation at loci encoding LMW-GS using SDS-PAGE and their gene-specific PCR primers, and allele-trait association analysis. Eight types of alleles were detected at the Glu-A3 locus by two primer pairs, in which Glu-A3c (31%) had the most frequent allele. Three specific primers detected 17 alleles at Glu-B3 locus, the high frequency of which belongs to Glu-B3f with 14.5%. For Glu-D3 locus; in total, 22 alleles were identified by four specific primers and Glu-D3h allele was the most frequent. 5, 9 and 9 alleles were identified by SDS-PAGE technique at the Glu-A3, Glu-B3 and Glu-D3 loci, respectively, the most frequent of which belongs to Glu-A3c with 40%. Using Nei's genetic variation index (H), the allelic variation for Glu-A3, Glu-B3 and Glu-D3 loci, were estimated as 0.818, 0.914, and 0.910, respectively. The mean allelic variation (H) for Glu-3 loci was 0.894 among the genotypes. The results of allele-trait associations demonstrated that Glu-A3a and Glu-A3e were associated with high volume of SDS-sediment. The Glu-B3b, Glu-B3f, Glu-B3d and Glu-B3a were associated with high protein content, wet and dry gluten, and bread volume as well as hectoliter weight. Moreover, Glu-D3r was correlated to kernel hardness. The identified allelic variation and associated alleles with quality traits provided helpful information for marker-assisted breeding programs to improve bread-making quality.