HMW-GS Composition And Its Correlation With Quality Characters Of Wheat In Hubei Province

Wheat is an important food crop,and the development of wheat industry is closely related to national food security and social stability in China.With the unremitting efforts of breeders,wheat breeding has realized the transformation from resistance breeding to high yield breeding,and then to high yield and high quality breeding.However,the present quality of the domestic wheat varieties still cannot meet the needs of consumers’different eating habits,and the breeding and improvement of special high-quality wheat varieties is urgent.High molecular weight glutenin subunits(HMW-GS),which are closely related to the processing quality of wheat,have been a focus subject for wheat quality genetic improvement research.This study analyzed and evaluated the composition of HMW-GS and grain quality traits of ninety approved varieties in Hubei province and seventy-three high-generation strains selected by Huazhong Agricultural University,providing reference for the genetic improvement of wheat specific quality in Hubei province.The main research results are as follows:1.A total of 15 alleles were detected in 163 wheat varieties(lines),among which 3alleles,1,2*,and Null,were detected at Glu-A1 locus;A total of 8 alleles were detected at Glu-B1 locus,including 7,7+8,7+9,6+8,13+16,13+19,14+15,and 17+18;Four allele types were detected at Glu-D1 locus,including 2+12,5+10,2+10,and 5+12.The subunit types are differences between the approved varieties and high generation lines,and the approved variety population mainly contain the subunits of Null(53.33%),7+8(51.11%),and 2+12(58.89%);The higher generation strain groups mainly contain the subunits of 1(58.90%),7+8(56.58%),and 2+12(53.42%).At the same time,the 13+16 and 13+19subunits are specific subunits in the approved variety population,while the 7 and 2+10subunits are specific subunits in the high generation lines.2.A total of 25 HMW-GS combination types were detected in 163 wheat varieties(lines),including 16 in the approved variety population and 21 in the higher generation line population.The subunit combinations with higher frequency in the approved variety population are:“N/7+8/2+12”(26.67%),“N/7+9/2+12”(12.22%),and“1/7+8/5+10”(10.00%);The subunit combinations with higher frequency in the higher generation population are:“N/7+8/2+12”(15.07%),“1/7+8/2+12”(12.33%),“1/7+8/5+10”(10.96%),and“1/7+9/2+12”(10.96%).There are 13 types of subunit combinations with quality scores above 8,accounting for 41.11%of the total number of approved varieties and 47.95%of the total number of high generation lines.3.The results of genetic diversity analysis indicate that the genetic diversity index(H_b)and effective allele number(A_e)of the approved varieties are 0.537 and 2.180,respectively,which are lower than the 0.581 and 2.492 of the high generation population.It indicates that the higher generation strain population has higher genetic diversity than the approved variety population.4.The correlation analysis between grain quality indexes and subunit combinations showed that there were significant correlations among grain quality indexes such as softening degree,starch content,grain hardness,wet gluten content,protein content,Zeleny sedimentation and falling number.The effect of single subunit loci on grain quality traits was small,but the effect of subunit combination was larger.For example,the combination of“1/7+9/5+10”and“1/14+15/2+12”could significantly improve the protein content,grain hardness,bulk density and wet gluten content of wheat varieties;The subunit combination of“1/7+8/5+12”,“1/6+8/5+10”,“N/7+9/2+12”and“N/14+15/2+12”could significantly reduce the protein content,grain hardness,bulk density and wet gluten content of the cultivars.According to GB/T 17320-2013,it was found that the proportion of weak gluten wheat in the high generation lines was higher than that in the approved varieties,which was the germplasm bank for breeding high quality weak gluten wheat.5.Through the correlation analysis of dough rheological properties and subunit combinations,it was shown that there was a wide range of significant correlations between farinograph indexes such as softening degree,tolerance index,stabe time,development time and farinograph index.7 subunit had the positive effect on softening degree and tolerance index,5+12 subunit had the negative effect on stabe time,and14+15 subunit had the positive effect on tensile energy,tensile resistance and tensile ratio.The“1/14+15/2+12”subunit combination had the positive effect on the formation time and stable time,and the“N/7+9/5+10”subunit combination had the positive effect on the tensile energy,tensile resistance and tensile ratio.In conclusion,through the analysis of subunits and subunit combinations of 163wheat germplasms in Hubei province and the evaluation of their grain quality traits and dough rheological properties,this study clarified the decisive role of wheat HMW-GS composition in wheat processing quality,and screened out the lines that can be used as parent materials for high-quality weak-gluten wheat in the high-generation lines,providing parental resources for wheat-specific quality breeding and providing reference for genetic improvement of wheat quality.