Studies On The Relationship Between High-molecular-weight Glutenin Subunits And Quality Characters Of Gansu-grown Spring Wheats

The composition of high-molecular-weight glutenin subunits (HMW-GS) of fifty-two spring wheat varieties which were mainly popularized in Hexi area in Gansu Province, including thirty-two local varities, fifteen bred varieties and five intro- duced varieties, had been ananlyzed. And the quality characters of these varieties were investigated such as: flour protein content, wet-gluten content, dry-gluten content, gluten index, SDS-sedimentation value and alevograph-consistency parameters (flexibility, extensibility, dough development time, dough stable time and bake power). Simple correlation ananlysis was applied to determine the relationship among these quality characters. Relationships between the HMW-GS composition and quality characters were studied. The result showed as follows:(l)There were significant and positive correlations between SDS-sedimentation value and other quality characters. The protein content had the same correlations with other traits as SDS-sedimentation value. Therefore SDS-sedimentation value or protein content could be applied in the early generation of the breeding, especially those varieties with higher SDS-sedimentation value, will be important in the good quality breeding wheat.(2)There were significant and positive correlations between subunit quality scores and quality characters such as gluten index, SDS-sedimentation value, P, TPr, Tol. So Glu-1 loci quality scores could be used to predict the quality of thevarieties.(3)The amount of subunits of HMW-GS affected the quality of varieties. More subunits, high quality.(4)The results were different when using different quality traits to determine the effects of the subunits. When using SDS-sedimentation value, Glu-Al loci was: l=2*>null; Glu-Dl loci was: 5+10>10>2+12=2+ll=ll=2+10; Glu-Bl loci was 22> 17+18>7+8=13+19=7+9>13+16. And when using dough development time, Al loci was 2*>l>null; Bl loci 7=22>7+8=7+9>13+16=17+18>13+19; Dl loci was: 5+10 >2+ll=10>2+12=ll>2+10. While taking bake power, Al loci was 2*>l>null; Bl loci was 7>22>7+9>7+8=17+18>13+19>13+16; Dl loci was 5+10>2+12>2+ll> 10>2+ 1O11. Whichever quality trait was adopted, some high quality subunits such as 5+10, 1 or 2* were related with high quality. It showed that the optimum method was using W.(5)The quality of the varieties with 5+10 subunit such as Ganchun No.20 and Wuchun No.2 was much higher than that of the others. So they could be used as the parents to cross with the cultivars with high yield. And it was possible to breed varieties with high yield and good quality. We suggested that SDS-PAGE should be adopted hi early generation of the breeding, together with grain protein, SDS-sedimentation value and other quality traits to improve the quality of wheat varieties in China.