Quantitative variation in the kernel proteins among 841 accessions of Triticum dicoccoides estimated by SDS-PAGE

The relative proportion and amount of proteins in five defined molecular weight (MW) regions (A1=above 71,000=71K, A2=71K-49K, A3=49K-31K, A4=31K-20K, A5=20K and less) were estimated by densitometric analyses of the amount of dye bound by kernel proteins (Fullington et al. 1980) of Triticum dicoccoides SDS-PAGE gels. These MW regions roughly correspond to the wheat protein solubility classes (Cole et al. 1981; Fullington et al. 1983). One purpose of the study was to select accessions whose seed proteins bind relatively high amounts of dye in the glutenin and albumin globulin regions. These accessions will be used for further in-depth studies as possible candidate donors of genes to improve the baking and nutritional quality of wheat. Marked differences in the quantitative relationships were found among the proteins in the five MW regions. Coefficients of variation (CV's) for the highest peak (i.e., most abundant protein) MW in different protein MW regions were similar for A1, A2 and A3, at 11.4, 11.7, and 11.1%, respectively, but only 4.1 for A4, and 10.6% for region A5. The CV for the highest peak MW overall was 29.8. Accession BP0649, for example, had over 44% of its protein in region A5, whereas BP0566 (lowest among the top 10%) had only 21.4% of its protein in that region. Over 37% of the proteins of accessions BP0649 and 0001 to 0005 was in region A5. At least 84 accessions with the highest amount of protein in region A5, and 13 accessions with more protein in region A1 than Chinese Spring may merit further evaluation as possible protein gene donors. High amounts of protein in A1 may be of importance in bread-baking quality, and in A4 and A5 for high lysine wheat. Accessions in both extremes were selected to test these hypotheses. All accessions are now or will be available in the USDA Wheat Collection.