Comparison of Allelic Variations at High-molecular-weight Glutenin Subunit Loci in Wheat Cultivars Released in Different Periods in China

High-molecular-weight glutenin subunit (HMW-GS) compositions of 171 hexaploid wheat cultivars and breeding lines released or bred recently from ten major wheat growing provinces and municipalities of China were determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Eighteen alleles and 40 different glutenin subunit patterns were identified, and 20 subunit patterns were observed only in one genotype. The most common alleles were 1 and Null at Glu-A1, 7+8 and 7+9 at Glu-B1, 2+12 at Glu-D1, and the prevalent subunit composition patterns were Null, 7+9, 2+12; Null, 7+8, 2+12; 1, 7+8, 2+12 and 1, 7+9, 2+12, accounting for 49.71% of cultivars analyzed. Compared with previous studies on old Chinese cultivars released or planted before, the frequencies of high breadmaking quality related subunits, such as subunit 1 and 5+10, together with allelic variations and subunit composition patterns, increased significantly, resulting Glu-1 quality score above seven. Further improvement of breadmaking quality of Chinese wheat cultivars should be focused on increasing the frequencies of subunit 5+10, 17+18 and other high quality subunits.