Studies On Qualification Of HMW-GS And The Correlation Between HMW-GS And Wheat Quality

Supervisor: Prof. Cui Dangqun Master Candidate: Dong ZhongdongIn order to study the relationships among high molecular weight glutenin subunits (HMW-GS), SDS-sedimentation value and protein content, 38 varieties(lines) of good agricultural characters were selected and planted in 200-2002 in Zhengzhou science-teaching farm of Henan Agriculture University. And the following indexes were mensurated : farinogramme, SDS-sedimentation value, protein content.To the correlation among farinogramme, SDS-sedimentation value and protein content, results from correlative analysis showed that the correlative coefficients of protein content with development time and with percentage of water were significant, and the correlations of protein content with stable time, with valorimeter value and with SDS-sedimentation value are more significant, as well as SDS-sedimentation with development time, with stable time and with valorimeter value, development time with stable time, with valorimeter value, and with softening of dough, and stable time with valorimeter value.To the effects of different subunits on fainogramme , SDS-sedimentation value, and protein content, 16 varieties (lines) were divided into three types, there were 5 varieties(lines) contained subunits 7+8 and 2+12 in the first type , 5 varieties (lines) contained subunits 7+9 and 2+12 in the second type, and 6 varieties (lines) contained subunits 7(8) and 5+10in the third type, results from analysis of variance indicated that: the difference of the means of water absorption and softening of dough was not significant ,and the order of mean of them is 1(for the first type)>2( for the second type) > 3 (for the thirdtype),3>2>1 respectively . the difference of the means of development time ,stable time , valorimeter value ,SDS-sedimentation value and protein content was significant, and the order of them was 3>1>2, 1>3>2, 3>1>2, 3>1>2, 3>l>2,therefore the order of effect of these subunits on baking quality of wheat was 3 ≥ 1 >2.To the dynamic accumulation of grain growth and subunits of different varieties (lines) with different subunits, the character of grain filling duration in the forepart is approximately same, but for the third type the grain growth became obviously slow in the evening. For the accumulation of subunit the quantity of the first and second type accumulated rapidly and reached the peak in 16-30 days post-anthesis, however, the third type always went up during the period. The first HMW-GS that appeared around 11 th-20th day after anthesis was the X-type subunit coded on glu-b1 loci. In addition , the quantity of subunit decreased in a way in the end. From the relationship between the accumulation of subunit and grain growth, there seemed to the accumulation of subunit decreased the speed of grain growth, that is to say, the accumulation of subunit is based on the loss of grain growth.To the qualification of subunits, based on analysis of regression and gradual regression, the results showed that the order of effect of subunits on wheat quality is 8(9)>7>2>12,for subunit pair, is 7+8(9)>2+12, and the increase of quantity of subunit 2 or 12 resulted in decrease of wheat quality, and subunit 7 or 8(9) reversed.