QTL Mapping Analysis Of Quality Related Traits In The Population Of Wheat-Aegilops Tauschii Substitution Lines

Aegilops tauschii（DD,2n=2x=14）is a D genome donor species of common hexaploid wheat,with a high level of genetic variability for disease resistance,productivity traits,and abiotic stress resistance.Through direct hybridization between wheat and Ae.tauschii or Synthetic hexaploid wheat,the excellent genes of Ae.tauschii can be introduced into common wheat,so as to enrich the genetic basis of wheat and provide excellent germplasm resources for wheat improvement.In this study,the BC₁F₁₁introgression lines population obtained by crossing and backcrossing between T015 and Z18 was used to construct a genetic linkage map using SSR molecular markers and wheat 55K gene chip,and correlation analysis was performed for quality-related traits（protein content,wet gluten content,water absorption rate,extensibility,sedimentation value,and stabilization time）in this population to further perform QTL initial mapping for these traits,clarify their location and effects on chromosomes,and screen candidate genes controlling quality traits for the improvement of wheat quality traits.The results of the study are as follows:1.T015 and Z18 were used to create a BC₁F₁₁ introgression lines population with Z18 as the genetic background,with a total of 277 lines.The phenotypic data of quality traits（protein content,wet gluten content,water absorption rate,extensibility,sedimentation value,and stabilization time）of each wheat line within the population were investigated and statistically analyzed under three planting environments（Kaifeng,Shangqiu,and Huaxian）,and BLUE value correction was performed.The analysis of the three environments and their BLUE value correction results showed that the phenotypic variation between families of the introgression lines population was large,all of which showed a continuous normal distribution and obeyed the requirements of QTL mapping.2.The correlation analysis between quality traits indicates that the dehumidibal content and water absorption rate,the water absorption is independent of the extension,and there is very significant or negatively correlated between the rest.The strongly relevance has a protein content and a wet gluten content,the extensibility and protein content,a settling value,and a protein content;moderately related wet rib content and elongation,wet rib content and settling value,extensibility and settling value,settling Value and stable time;weakly related protein content and water absorption,protein content and stable time,wet gluten content and stable time,water absorption and settling value,water absorption,water absorption,water absorption,and stable time,elongation,and stable time.Analysis of variance showed that genotypes,years,genotypes and years of interaction of sexual phenotypes have achieved extremely significant levels（P<0.01）.3.With SSR molecular markers and wheat 55K gene chips,QTL positioning is performed on three environments and Blue values,which is detected to 73 QTLs associated with protein content,wet rib content,water absorption rate,elongation,settling value,and stabilization time,respectively.There are 7,9,16,13,11,17,distributed at 1D,2D,3D,5D,6D,7D chromosome.Among them,the QTLs positioned on the 5D chromosome is up to 30,and QTLs related to quality traits are not detected on the 4D chromosome.In the 73 QTL positioned,34 main QTLs,the main QTL related to the settling value,a total of 9,with the least 3 of the main QTL related to the wet rib content.4.According to the Chinese Spring Wheat Gene Annotation File,functional gene screening of QTL loci for relevant quality traits mapped by the BC₁F₁₁ population yielded the following results:The Q.pro-HX.1 locus that was significantly associated with protein content was in the interval of AX-111626804-AX-108952024 on chromosome 1D,physically located at 10.69–29.25 Mb,within which one gene,Traes CS1D02G001100,was found to encode gamma-gliadin.The Q.glu-SQ.1 locus that was significantly associated with wet gluten content was in the AX-109906322-AX-10941290 interval of the1D chromosome at a physical location of 376.07-399.43 Mb,within which a gene,Traes CS1D02G317211,was found that encodes the HMW-GS Dx.The Q.ext-KF.3 locus significantly associated with water uptake was in the AX-95210238-AX-9517053 interval on chromosome 5D,physically located at 8.15–26.19 Mb,within which one gene,Traes CS3D02G433755,was found,encoding Puroindoline.The Q.ext-KF.3 locus significantly associated with elongation was on the 3D chromosome with a marker interval of AX-108887593-AX-94566074 and a physical position of 483.38–533.64 Mb,within which one gene,Traes CS3D02G433755,was found,encodingα-gliadin.The Q.pro-HX.1 locus significantly associated with stabilization time was on chromosome 1D with a marker interval of AX-111257207-AX-10948553 and a physical location of 6.15–26.19 Mb,within which a gene,Traes CS1D02G001400,was found encodingγ-gliadin.In this study,a genetic map was constructed based on SSR marker and SNP marker information in the D genome of wheat.Meanwhile,phenotypic identification was carried out for 6 quality-related traits of BC₁F₁₁ population.Combined with phenotypic and genotype data,QTL mapping for wheat quality traits was carried out.Whether there are genes associated with quality traits in the locus interval,so as to verify the correlation between the locus and quality traits,lay a good foundation for fine mapping and mapping cloning of QTL for important agronomic traits,and enrich the genetic background of the D genome.