Genetic Diversity of High-Molecular-Weight Glutenin Subunit Composition in Chinese Wheat Landraces

The high-molecular-weight glutenin subunit(HMW-GS) composition of 76 representative accessions of wheat landraces,collected from nine agro-ecological zones in China,were examined using sodium-dodecyl-sulphate polyacrylamide-gel electrophoresis(SDS-PAGE).The correlation between diversity indexes at Glu-1 locus and altitude,mean annual precipitation,or mean annual temperature was also analyzed.The results indicated that 19 accessions(25.0%) were heterogeneous for HMW glutenin subunit composition,and contained 2-4 HMW-GS compositions generally.At Glu-1 locus,a total of 14 different glutenin alleles were observed and the number of alleles at Glu-A1,Glu-B1,and Glu-D1 was 2,7,and 5,respectively.Three novel alleles were identified,consisting of two alleles at Glu-B1 and one allele at Glu-D1 locus.The 14 alleles resulted in 16 different HMW subunit combinations,and the combination(null,7+8,2+12) was the major type with the frequency of 69.7%.The genetic diversity indexes for HMW glutenin subunits varied among agro-ecological zones,and were negatively correlated with mean annual precipitation and mean annual temperature.Environmental stress is speculated as an important factor for the differentiation of diversity in wheat landraces across regions.