Marker-Assisted Selection Of HMW-GS Dx5(+Dy10) Gene And Its Effect On Wheat Quality Breeding

The high molecular weight glutenin subunits (HMW-GSs) in wheat are largelyresponsible for wheat kernel quality. The subunits Dx5 and Dy10 are highly related tosedimentation volume, gluten index, baking quality, et al, compared with the subunits Dx2and Dy12 or Dx4 and Dy12, which are encoded by the same loci Glu-1D. It is stronglybelieved by many researchers in China that it is a more important way to improve the currentChinese wheat cultivars or breeding lines with transferring good HMW-GSs into Chinesehigher-yielding wheat cultivars or lines from overseas cultivars or lines. To improve Chinese higher-yielding wheat quality, hybridization and backcross methodsin this study were used to transferring Dx5+Dy10 into six Chinese wheat cultivars or linesfrom two French cultivars or lines. The plants and lines with Dx5 gene were selected byspecific PCR marker in random progeny. The different progeny of cross and backcross hadbeen obtained in greenhouse and field. In order to analyze reliability and stability of results of PCR detection, hereditary rule oftarget genes in early breeding population, and results of PCR detection in same individualplants in different growing different periods were studied. Furthermore results of PCRdetection were compared with those of SDS-PAGE method in pure lines. To evaluate theeffect on kernel yield and quality of early generation PCR molecular selection for target genes,the comparative method of grain yield and quality was used between the generation groupwith objective genes and without objective genes. The results in this study were as follows: Through the molecular marker selection for HMW-GS Dx5 gene in early randomgeneration, the subunit Dy10 gene was screened at the same time. It had the advantage of highprediction value, good repeat, the significant improvement of wheat kernel quality, and couldnot change the yield distribution in the current and late generations. It was also feasible forcharacters to select further wheat late generations that originated from early generations usingmolecular marker selection. Therefore it was a very feasible and efficient way for molecularmarker to select genotypes with good HMW-GS genes in wheat early generation. The F3generation was the critical period for selections of molecular marker for objective genes,4 小麦谷蛋白亚基编码基因 Dx5(+Dy10)的分子选择及效果研究swelling index of glutenin (SIG) test and small-scale SDS sedimentation volume test. The target gene molecular marker selection method could improve protein quality in thedescendents, but not do protein quantity and kernel yield. If protein content and kernel yieldin generations were paid attention to selecting at same time, the frequency of better kernelquality and higher-yielding lines should highly appear in the generations. The distribution ofquality, yield in progeny was significantly related to those of their parents. In order to improve higher-yielding wheat quality characters, backcross method wasmore efficient than cross method because progeny in backcross breeding still retainedhigher-yielding characters of their recurrent parents. However suitable number of times ofbackcross was important if progeny held better quality characters of no-recurrent parents. BC6 and F7 of twelve crosses had been raised respectively. The near-isogenic lines at theGlu-D1 locus will be obtained after BC6 are inbreeded one and two times in the future.Different types at HMW-GS, LMW-GS and gliadins will also obtained by detection ofcomponents of protein in BC6 and F7. It will be feasible to study effect of different proteincomponents on quality. Some higher-yielding, better-quality lines, which had been raised inthis study, may be parents of quality breeding and take part in cultivars test in the future. According to the results of this study and experience of wheat breeding, the procedure ofpedigree method on selection of strong-gluten wheat was put forward. This...