Effect Of Variation Of HMW-GS And Waxy Gene On Quality Improvement In Medium-gluten Wheat

High-molecular-weight glutenin subunits(HMW-GS)and Waxy proteins(Wx proteins)are major contributors to wheat flour quality and end-use quality.To evaluate the effect of HMW-GS and Wx protein on physicochemical quality of medium gluten wheat and properties of cooked Chinese white salted noodles and screen desirable lines for making high quality noodles,two studies were carried out:(1)trail one including four types of recombinant inbred lines(RILs)with different HMW-GS compositions derived from Yangmai 16 and Zhengmai 9 was contributed to evaluate the effect of the allelic variation at Glu-A1 and Glu-D1 on protein content,wet gluten content,gluten index,SDS value,farinograph parameters,alveograph parameters and cooked Chinese white saltd noodles quality(sensory evaluation and textural properties);(2)trail two focused on two homozygous wheat lines derived from the bread wheat cv.Zhengmai 9(1/7+9/5+10,AABBDD)and waxy wheat cv.Yangnuomai 1(1/7+9/2+12,aabbdd),and the effect of 5+10 subunits and Wx gene deficiencies on protein properties,starch characteristics and noodle quality were clarified.The main results were as follows.1.The variation of single subunit pair at Glu-A1 or Glu-D1 made little significant contribution to protein content.However,substantially difference was detected on protein content when Null at Glu-A1 changed to 1 subunit,in addition,subunit pair 2+12 at Glu-D1 changed to 5+10.Subunit 1 at Glu-A1 made major effect on wet gluten content while subunit pair 5+10 made more influence on gluten index than tose of their counterpart allelic variation.2.Subunit pair 5+10 had evidently positive effect on dough development time,but was not not important determinants for dough stability time.For P value and W value of alveograph,the line of subunit composition 1/7+9/5+10 was higher than that of Yangmai 16.And changes of the dough extensibility(L value)of lines of different HMW-GS composition were not pronounced.3.The results of sensory evaluation and textural properties of noodles had no significant differences among four RILs and Yangmai 16,which indicated that Yangmai 16 had a strong foundation of gluten,and there were not significantly improvement in noodles quality of Yangmai 16 when changes only in HMW-GS composition.It is also suggested that starch quality improvement could be paid more attention to making better quality noodles.4.Line 1 and line 2 have protein quality similar to Zhengmai 9,and better to Yangnuomai 1.The results showed that amylose content in line 1 and line 2 reduced 1.5 and 2.5 percentage points respectively,comparing to that in Zhengmai 9.Line 1 and line 2 with Wx-A1 and Wx-D1 deficiency,respectively,especially the latter,exhibited higher peak viscosity,breakdown and swelling power of flour than Zhengmai 9.5.The results provided that 5+10 subunits could significantly increase hardness and chewiness of TPA parameters,while single Wx gene dificiency pronounced improve firmness score and smoothness score of cooked noodles.In general,the line 2 with 5+10 subunits and Wx-D1 gene dificiency had better cooked noodle quality and higher sensory score.