The Composition Of High Molecular Weight Glutenin Subunits Of Wheat Varieties (Lines) In The South Of Huanghuai Region And Their Relationship With Quality

Wheat is the main food crop in China,which provides the vast majority of carbohydrates.Along with the improvement of people's living standard,the diversity of wheat varieties has became the trend of times.People put forward higher requirements on the quality of wheat,thus quality improvement has been one of the important goals in wheat breeding.Generally,the quality of wheat can be divided into nutritional quality and process quality.There are a number of important indicators for the evaluation of quality such as SDS sedimentation value,protein content,dough strength,ductility and baking quality indicators,etc.Actually,these quality indices also provide important theoretical references for generation selection in wheat quality breeding.High Molecular Weight Glutenin(HMW-GS)in wheat has played a key role in determining baking quality,rheological properties and gluten properties,which has been recognized as a key factor affecting the quality of wheat flour.Therefore,elucidating the relationship between HMW-GS compositions and quality traits can provide important clues for wheat quality genetic improvement.In this study,167 materials(Newly bred varieties,Popularized varieties,Regional testing varieties and Historical varieties)from the South of Huang-huai Wheat Region were collected and then the types and composition of HMW subunits were detected.Meanwhile,these varieties were planted and identified at three locations in 2014(Shangqiu Academy of Agricultural Sciences,Zhumadian Academy of Agricultural Sciences and Henan Agricultural University),respectively.The related quality indices were determined by means of the instrument such as DA7200 near infrared spectrometer,Sedimentation value instrument,Mixograph and Farinograph,etc.Also,the quality performance of materials with different types of subunit compositions and combinations were analyzed and evaluated.The results were summarized as follows:1.Ten types of HMW-GS subunits were found in 167 Wheat varieties(lines).At the Glu-A1 locus,3 types of subunits including 1(72.46%),2*(0.6%),N(26.95%)were detected,respectively;at the Glu-B1 locus,4 types were found such as 7+8(24.55%),7+9(61.08%),14+15(11.98%),17+18(2.4%);at the Glu-D1 locus,3 types including 2+12(52.69%),5+12(1.2%),5+10(46.11%)were detected.2.A total of 17 types of subunit combinations were found in 167 varieties.Among them,1/7+9/2+12 subunit combination presented the highest frequency(25.75%),followed by 1/7+9/5+10(21.56%),1/7+8/5+10(11.38%)and N/7+9/2+12(10.78%).In all,the frequencies of others were less than 10%.3.Highly significant differences(p<0.01)were found between different locations involving quality parameters such as protein content,wet gluten,SDS sedimentation value and Mixograph,which indicated that environment conditions played an important role in determining quality traits.Also,highly significant differences were observed between different varieties(lines)(p<0.01),especially that the range of individual characters was very large.Quality indices of wheat varieties(lines)in different locations displayed vast differences.Interaction effect between location and variety almost had significant impacts on quality traits except peak band width,high band width and band width(p<0.05).4.At Glu-A1 locus,1 subunit showed higher effect than N subunit;at Glu-B1 locus,7+8 > 17+18 > 14+15 > 7+9;at Glu-D1 locus,the summation effect of 5+10 was larger than that of 2+12.Significant differences from different subunits compositions were found in quality traits such as protein content,wet gluten content,hardness value,SDS precipitation value,peak band width,peak area,8 min band height,8 min curve area,water absorption,formation time and stability time(p<0.05).The comprehensive quality of N/7+8/2+12,1/7+8/5+10 and 1/7+8/2+12 was good,and that of N/14+15/5+10 and N/7+9/2+12 was poor.Wheat varieties with good subunit of 5+10 could not necessarily contributed to get better quality.So,these results showed that it could be possible but hardly probable to get high quality by simply piling up subunits,and breeders should select the individuals in the direction of purpose in wheat quality improvement.