Studies On HMW-GS Genetic Variation Of Winter Wheat Germplasm Resources In Gansu

With the analysis of high molecular weight glutenin subunits (HMW-GS) of 361 winter wheat varieties (included local varieties, introduced varieties, bred varieties and bred new lines) in Gansu, Compositions, evolvement and diversity of HMW glutenin subunits were studied. On the basis of HMW-GS SDS-PAGE, the results were obtained as follows: (1) High-molecular-weight glutenin subunit (HMW-GS) compositions of 361 winter wheat varieties in Gansu were determined by Sodium Dodecyl Sulphate Polyacrylamide Gel Electrophoresis (SDS-PAGE). The result showed that these winter wheat varieties had plentiful HMW-GS types. Glu-A1 encoded three subunits of 1, 2* and null; Glu-B1 encoded eight subunits of 7, 13+16, 14+15, 17+18, 6+8, 6+8*, 7+8, 7+9; Glu-D1 encoded six subunits of 2+10,2+11,2+12,4+12,5+10,5+12. There were three major allelic variants at Glu-1 loci in winter wheat varieties in Gansu, Glu-A1c [null (68.41%)], Glu-B1b [7+8(65.11%)], Glu-D1a [2+12(75.55%)], respectively.(2) There are 35 HMW-GS types in these winter wheat varieties. The frequency of N, 7+8,2+12 is 42.58%, which is the major type. Good subunit composition is lack.(3) There are different frequencies of HMW-GS in different winter wheat germplasm resources. The types of local varieties, introduced varieties, bred varieties and bred new lines are 11,22,19,15,respectively. The type Null, 7+8,2+12 is 77.24 percent of local varieties. The frequencies of all subunits in bred varieties have a well-proportioned distributing. The frequency of 5+12,1 and 7+9 in mordern varieties is more than it in landraces(4) The difference in genetic richness between the landraces and bred varieties at Glu-1 is small. However, the genetic dispersion index (Simpson index) based on allelic variations and their frequency at Glu-A1, Glu-B1 and Glu-D1 suggests that the genetic diversity of modern varieties is much higher than the landraces'. Of the three loci, the genetic diversity of Glu-B1 is the highest, then Glu-D1, while that of Glu-A1 is always the lowest. (5) From the genealogy of bred varieties, it was deduced that the winter wheat quality in Gansu is inferior. The high quality subunits are lack and the score of Glu-1 in Gansu is lower than the average score of it in china. Some germplasms with high quality subunits and rust-resistant were screened in this study, they can be used in breeding.