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

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. 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 <em>Glu-1 </em>and <em>Glu-3 </em>loci, respectively. In addition, the presence of the 1B.1R translocation was investigated. Three, six, and two 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, 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 77, 46.2, and 54%, respectively. Four, five and five allelic variations were present at the <em>Glu-A3,</em> <em>Glu-B3 </em>and<em> Glu-D3 </em>loci, with <em>Glu-A3e</em>, <em>Glu-B3i and Glu-D3b </em>LMW-GS dominating, with frequencies of 46.2, 54 and 69.2%, respectively. The frequencies of allelic variation at <em>Glu-1 </em>and <em>Glu-3 </em>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 <em>Glu</em>-<em>1 </em>such as 1, 7</strong><strong>+</strong><strong>8, 5</strong><strong>+</strong><strong>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.</strong>