Allelic variation at the storage protein loci of 55 US-grown white wheats

Fifty soft white and hard white wheat cultivars (Triticum aestivum L.), and five club wheat cultivars (T. compacium L.) were partially characterized in terms of their storage protein compositions, i.e. gliadins, and high molecular weight and low molecular weight glutenin subunits (HMW-GS and LMW-GS, respectively); At the Glu-1 loci, HMW-GS composition 1, 7 + 9, 2 + 12 was found to be predominant, being expressed in 11 cultivars out of 55. The most common alleles at the loci coding for gliadins and LMW-GS were found to be Gli-A1/Glu-A3a (43.6%), Gli-B1/Glu-B3b (36.4%), Gli-D1a/Glu-D3a (38.1%) and Gli-D1i/Glu-D3a (21.8%). Two-dimensional fractionation (acid-polyacrylamide gel electrophoresis (A-PAGE) x sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE)) of reduced and alkylated glutenins revealed that the number and the relative mobility of LMW-GS polypeptides were different from those reported for the corresponding Glu-3 alleles of hard-bread wheat cultivars. This result could account for the different technological properties of soft white wheats compared with hard-bread wheat cultivars, owing to the major impact of LMW-GS on dough quality.