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 agro-climate 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, and 2 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, 5, 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.