Genetic diversity of high-molecular-weight glutenin subunit compositions in bread wheat landraces originated from Turkey

Focusing on 116 bread wheat landraces, this study investigated high molecular weight glutenin allele polymorphism, gene diversity, genetic variation and linkage disequilibrium (LD) in Glu-1 loci. To identify gluten alleles, sodium dodesyl sulphate-polyacrylamide, gel electrophoresis was used and for statistical analyses POPGENE software was employed. The results indicated that average genetic variation (h) was the highest in Glu-B1 (0.6421) and the lowest in Glu-A1 locus (0.4548); genetic similarity ratio (I) was the highest in Glu-B1 (1.4170); the highest average genetic diversity (Ht) was observed in Glu-B1 (0.6575) and the lowest diversity was observed in Glu-A1 (0.4558). It was also observed that genetic diversity in Glu-1 locus was largely due to intra-population variations. Inter-population gene flow was also calculated as 4.0051. Marmara and Southeastern Anatolia regions, the results further indicated, had the highest (2.8691) and lowest (0.1694) heterozygosity. Genetic erosion risk for Turkish bread wheat landraces was also seen to be high. Considering the mutual analyses of subunits of nationwide wheat landraces, it is possible to speculate about a limited migration between the landraces. LD of the landraces was largely because of this limited migration and/or epistatic natural selection. Since Turkey is known as the gene centre for major cereals including wheat, barley, rye and oat, where they diversified and spread throughout the world, studying the gluten allele diversity of Turkish bread wheat landraces is important. In addition, this study has revealed the applicability of LD, and neutrality tests to gluten protein diversity for the first time.