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

Abstract

<strong>Allelic variations at the <em>Glu-1 </em>and <em>Glu-3 </em>loci play an important role in determining dough visco-elastic properties and bread making quality. Fifty-nine bread wheat cultivars released in Iran since 1951 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 <em>Glu-1 </em>and <em>Glu-3 </em>loci, respectively. In addition, the presence of the 1B.1R translocation was investigated. Three, eight, and four allelic variations were present at <em>Glu-A1</em>, <em>Glu-B1</em>, and <em>Glu-D1</em> loci, respectively. Subunits 2*, 7</strong><strong>+</strong><strong>8, 7</strong><strong>+</strong><strong>9, and 2</strong><strong>+</strong><strong>12 are the dominant HMW-GS, at <em>Glu-A1</em>, <em>Glu-B1</em>, and <em>Glu-D1</em>, with frequencies of 45.8, 39, 25.4, and 59.3%, respectively. Five, eight and four allelic variations were present at the <em>Glu-A3,</em> <em>Glu-B3 </em>and<em> Glu-D3 </em>loci, with <em>Glu-A3c</em>, <em>Glu-B3b and Glu-D3b </em>LMW-GS dominating, with frequencies of 52.5, 39 and 59.3%, respectively. The frequencies of allelic variation at <em>Glu-1 </em>and <em>Glu-3 </em>differ greatly in different regions. Among the 59 cultivars/varieties examined in this study, four genotypes were local varieties (6.8%), 27 (45.8%) bred in the national breeding program and 28 (47.4%) 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 5.5, 7.6 and 7.7 respectively. It was concluded that integration of desirable subunits at <em>Glu</em>-<em>1 </em>such as 1, 7</strong><strong>+</strong><strong>8, 5</strong><strong>+</strong><strong>10, 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.</strong>