Genetic diversity for high- and low-molecular weight glutenin subunits in local and commercial bread wheat cultivars released since 1951 in Iran: II- Rainfed

Allelic variations at the Glu-1 and Glu-3 loci play an important role in determining dough visco-elastic properties and bread making quality. Thirteen bread wheat cultivars released in Iran since 1930 from three different agroclimate zones adapted for dryland conditions, were examined for their high (HMW-GS) and low (LMW-GS) - molecular-weight glutenin subunits composition, controlled at the Glu-1 and Glu-3 loci, respectively. In addition, the presence of the 1B.1R translocation was investigated. Three, six, and two allelic variations were present at Glu-A1, Glu-B1, and Glu-D1 loci, respectively. Subunits 2*, 7+8, and 2+12 are the dominant HMW-GS, at Glu-A1, Glu-B1, and Glu-D1, with frequencies of 77, 46.2, and 54%, respectively. Four, five and five allelic variations were present at the Glu-A3, Glu-B3 and Glu-D3 loci, with Glu-A3e, Glu-B3i and Glu-D3b LMW-GS dominating, with frequencies of 46.2, 54 and 69.2%, respectively. The frequencies of allelic variation at Glu-1 and Glu-3 differ greatly in different regions. Among the 13 cultivars/varieties examined in this study, three genotypes were local varieties (23%), four (31%) were bred by Iran’s national breeding program, and six (46%) originated from international nurseries. The average quality scores based on HMW-GS for local varieties, genotypes from the national breeding program and international nurseries was the same with a score of 8. Research led to the conclusion that integrating desirable subunits at Glu-1 such as 1, 7+8, 5+10, should be the main focus of the country’s rainfed wheat breeding program, to achieve the goal of improving of gluten quality in Iranian bread wheat cultivars adapted to dryland conditions.