Genetic diversity for high- and low-molecular weight glutenin subunits in local and commercial bread wheat cultivars released since ۱۹۵۱ in Iran: I- Irrigated

Allelic variations at the Glu-۱ and Glu-۳ loci play an important role in determining dough visco-elastic properties and bread making quality. Fifty-nine bread wheat cultivars released in Iran since ۱۹۵۱ from four different agro-climate zones, were examined for their high (HMW-GS) and low-molecular-weight glutenin subunit (LMW-GS) composition, controlled at the Glu-۱ and Glu-۳ loci, respectively. In addition, the presence of the ۱B.۱R translocation was investigated. Three, eight, and four allelic variations were present at Glu-A۱, Glu-B۱, and Glu-D۱ loci, respectively. Subunits ۲*, ۷+۸, ۷+۹, and ۲+۱۲ are the dominant HMW-GS, at Glu-A۱, Glu-B۱, and Glu-D۱, with frequencies of ۴۵.۸, ۳۹, ۲۵.۴, and ۵۹.۳%, respectively. Five, eight and four allelic variations were present at the Glu-A۳, Glu-B۳ and Glu-D۳ loci, with Glu-A۳c, Glu-B۳b and Glu-D۳b LMW-GS dominating, with frequencies of ۵۲.۵, ۳۹ and ۵۹.۳%, respectively. The frequencies of allelic variation at Glu-۱ and Glu-۳ differ greatly in different regions. Among the ۵۹ cultivars/varieties examined in this study, four genotypes were local varieties (۶.۸%), ۲۷ (۴۵.۸%) bred in the national breeding program and ۲۸ (۴۷.۴%) originated from international nurseries. The average quality scores based on HMW-GS for local varieties, genotypes from the national breeding program and international nurseries were ۵.۵, ۷.۶ and ۷.۷ respectively. It was concluded that integration of desirable subunits at Glu-۱ such as ۱, ۷+۸, ۵+۱۰, must be used as the core focus of the breeding program, which could lead to the improvement of gluten quality in Iranian bread wheat cultivars.

Keywords:

Glutenin , allelic variation , SDS-PAGE , Triticum aestivum