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 chara cterized 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 composit ion 1, 7 + 9, 2 + 12 was found to be predominant, being expressed in 1 1 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/Gl u-B3b (36.4%), Gli-D1a/Glu-D3a (38.1%) and Gli-D1i/Glu-D3a (21.8%). Tw o-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 cultiva rs, owing to the major impact of LMW-GS on dough quality.