Variation for Glutenin and Waxy Alleles in U.S. Hard Winter Wheat Germplasm.
Xueyan Shan, Sally Clayshulte, Patrick Byrne, and Scott Haley. Colorado State Univ, 1170 Campus Delivery, Dept of Soil & Crop Sciences, Fort Collins, CO 80523
Knowledge of the grain quality alleles present in elite wheat germplasm will help breeders plan crosses and will aid in determining allelic effects on specific quality traits. We conducted a survey of high and low molecular weight glutenin subunits (HMW-GS and LMW-GS, respectively) and waxy allele composition in 111 winter wheat cultivars and advanced lines developed in the U.S. Hard Winter Wheat Region since 1991. At the HMW-GS Glu-A1 locus, 76.1% of the entries had the b allele (encoding subunit 2*), 21.2% carried the a allele (subunit 1), and 2.7% had the c (null) allele. Alleles identified at the HMW-GS Glu-B1 locus were c (subunits 7+9; 47.7% of entries), b (subunits 7+8; 33.3%), e (subunit 20; 7.7%), i (subunits 17+18; 6.3%), and w (subunits 6*+8*; 5%). At the HMW-GS Glu-D1 locus, 80.6% of the entries carried allele d (subunits 5+10), 11.3% had allele a (subunits 2+12), 7.2% carried allele b (subunits 3+12), and 0.9% had allele e (subunits 2+10). Glu-B1 and Glu-D1 allele frequency differed significantly (P<0.01) from a previous study of U.S. Hard Winter Wheat germplasm developed from 1970 to 1990. At LMW-GS loci, five Glu-A3 alleles, nine Glu-B3 alleles, and five Glu-D3 alleles were identified, revealing greater variation than for HMW-GS. Polymerase chain reaction analysis detected 10 entries with the null Wx-B1 allele and seven with the null Wx-A1 allele. This survey allows comparisons of HMW-GS and waxy allele compositions with U.S. Hard Winter Wheat germplasm from previous eras and provides baseline data on LMW-GS composition.