Allelic Variation and Composition for Seed Proteins in Synthetic Hexaploid Wheats (2n=42, BBAuAuDD)

Abstract

Seven hexaploid synthetic wheats (2n=42, BBAuAuDD), derived by crossing accessions and hybrids from T. turgidum (2n=28, BBAuAu) to diploid Aegilops tauschii (2n=14, DD), following by colchicine treatment for chromosome doubling, were subjected for seed protein analysis. Amphidiploids № 531 and № 107 revealed x-type subunit 1 at the Glu-A1 locus, but four other synthetics (№ 32, 106, 530, 532) expressed subunit 1Ax1.1, uncommon for bread wheat, that could be an example of expanding allelic diversity for HMW-GS along with the D-genome derived genes. At the Glu-B1 locus, five x-type subunits, viz., 7, 13, 17, 14 and 22, and four y-type subunits viz., 8, 16, 18 and 15, and their five combinations were detected. Diversity at the Glu-D1 was found to be greater than the variety of genes contained at Glu-A1 and Glu-B1 loci. In synthetics, the subunit 1Dx1.5+1Dy10 was predominantly observed, which is different from the T. aestivum genome and affect the wheat quality to great extent. Other detected D-genome subunits were 1Dx2+1Dy11 and 1Dx4+1Dy10.1. LMW-GS discovered two different lines in each of № 32, 530 and 532 (with b and c alleles) that was further supported by the gliadin compositions. D-genome synthetic hexaploid wheats seemed to be excellent sources for selecting different glutenin compositions in wheat breeding, as well for gliadins, revealing diverse ω- and γ genes