Genetic Linkage Map of Glu-D1 and Allelic Variation of HMW Glutenin Subunits in Some Iranian Bread Wheat genotypes

Abstract

<span>High-molecular weight </span><span class="shorttext"><span>(</span></span><span>HMW</span><span lang="AR-SA" dir="RTL"> (</span><span>glutenin </span><span>subunits </span><span>are encoded by the </span><em><span>Glu-1 </span></em><span>loci </span><span class="shorttext"><span>(</span></span><em><span>Glu-A1</span></em><span>, </span><em><span>Glu-B1 </span></em><span>and </span><em><span>Glu-D1</span></em><span lang="AR-SA" dir="RTL"> (</span><span>on the long arms of chromosomes 1A, 1B and 1D</span><span>.</span><span> In the present study, we constructed genetic linkage map of </span><em><span>Glu-D1</span></em><span>and then investigated</span><span> the allelic variation</span><span> of HMW glutenin subunits at Glu<em>-A1</em> and <em>Glu-D1</em> gene loci in 30 Iranian genotypes using </span><span>Functional </span><span>markers. </span><em><span>Glu-D1</span></em><span> was located at 50.8 cM on </span><span>chromosome 1D and it was </span><span>tightly linked to wPt-3743 marker </span><span>(>1 cM)</span><span>. QTL analysis using composite interval mapping </span><span>detected one significant QTL for grain yield</span><span> (GY) on </span><span>chromosome 1D</span><span>. This QTL (</span><em><span>QYld.abrii-1D</span></em><span>) was located between wPt-3743 and <em>Glu-D1</em> gene locus. </span><span>Allelic variation</span><span> of HMW glutenin subunits</span><span> showed </span><span>the most frequent alleles were the null allele at </span><em><span>Glu-A1</span></em><span>and </span><span>Dx2+Dy12 </span><span>alleles</span><span> at Glu-D1loci</span><span>. </span><span>The frequency of Null alleles or 1 and 2* were 40% and 60% respectively. Only 9 genotypes included allelic combination of Dx5+ Dy10 and the rest of genotypes had Dx2+Dy12 in the <em>Glu-D1</em> locus. According to the <em><span>Nei's</span></em> genetic diversity index, alleles at <em>Glu-A1 </em>locus have more dispersion in genotypes compared to<em> Glu-D1</em> locus. The cluster analysis of data based on the Simple Matching coefficient and UPGMC methods, classified the genotypes into four groups. Six genotypes including: Bezostaya, Tajan, Navid, Karaj1, Neyshabour, and Golestan had Ax2* and Dx5+ Dy10 subunits at <em>Glu-A1</em> and <em>Glu-D1</em> gene loci. Identification of genotypes with suitable allelic combinations can be used in breeding programs, especially in hybridization. </span>