| As one of the world’s main grain crops and with the demand for wheat demands increasingly by the world’s growing population.Most of the wheat varieties bred under modern breeding models have been selected using repeated groupings of wheat backbone lines,resulting in a gradual reduction in the genetic diversity of newly bred wheat and a narrowing of the available superior genetic resources.Synthetic hexaploid wheat was created by a distant cross between Triticum turgidum and Aegilop tauschii,carrying the abundant wild genetic resources of Aegilop tauschii,which can be of great help in improving the yield and quality of wheat.Therefore,based on the progeny population constructed by crossing synthetic hexaploid wheat and common cultivated wheat,genetic studies on grain and quality traits such as grain length,grain width,thousand grain weight and grain protein content of the population are conducted to explore excellent genetic resources,which is of great significance for wheat breeding.In this study,two recombinant inbred lines,XN389×KU2039 and XN389×KU2098(abbreviated as S population and J population,respectively),were constructed using common cultivated wheat XN389 and synthetic hexaploid wheat KU2039 and KU2098 as parents.The phenotypic traits of grain traits and quality traits were measured in the two RIL populations for two years using intelligent phenotype detection instruments.Then QTL analysis was conducted for ten phenotypic traits in combination with the two high-density genetic maps constructed,with the following main findings:1.The phenotypic values of grain traits and quality traits were measured in both RIL populations for two years using an intelligent phenotypic detection instrument,while the grain length and thousand grain weight were measured manually.Statistical analysis showed that the instrumental values were reliable and could be used for genetic analysis.The results of the analysis(R~2>0.85)showed that all phenotypic traits differed significantly or extremely significantly between the two pairs of parents,the frequency distribution of all phenotypic traits in the two environments and BLUP values were approximately normally distributed,showing the typical genetic characteristics of quantitative traits,so these two RIL populations could be used for QTL analysis of ten phenotypic traits.2.The genotype data of two RIL populations were obtained based on wheat 55K SNP microarray technology,and two high-density genetic maps were constructed.The genetic map of XN389×KU2039 population contained 2688 BIN markers and a total of 24linkage groups,with a linkage map length of 4588.1 c M and the average marker density is1.71 c M.The genetic map of XN389×KU2098 population contained 2826 BIN markers,with 23 linkage groups,a linkage map length of 4603.73 c M and the average marker density is 1.63 c M.3.Based on the two high-density genetic maps constructed and two years of phenotypic data,QTL mapping was conducted for 10 phenotypic traits.A total of 149QTLs were detected in the two populations over two years,covering 21 chromosomes,with63 detected in the XN389×KU2039 population and 86 in the XN389×KU2098population,and the explanation rate of individual QTL phenotypic variation ranged from0.91%to 49.88%.A total of 96 QTLs were detects in both populations related to grain traits.A total of 39 QTLs were detects for quality traits,and 14 QTLs related to heading date,respectively.Among them,there were 69 phenotypic variants with an explanation rate greater than 10%.4.There were 22 QTLs that could be detected twice or more repeatedly in both RIL populations and could explain phenotypic variation rate of more than 10%in all,which were stable QTL.10 QTLs in the XN389×KU2039 population,QGL-S-7D,QGW-S-2D,QTGW-S-6A-2,QKA-S-7D.1,QKP-S-7D.1 associated with grain traits,QHD-S-2D related to heading date,QGPC-S-5A,QWGC-S-5A and QSC-S-5A related to wet gluten content and starch content,respectively.12 QTLs were detected in the XN389×KU2098population,QGL-J-1A,QGW-J-1B.2,QTGW-J-4D,QGLWR-J-1A,QGLWR-J-5A.2,QKA-J-1B and QKP-J-6A-2 associated with grain traits,QHD-J-2D-1 related to heading date,QGPC-J-4A related to grain protein content,QWGC-J-3B and QWGC-J-6A-2 related to wet gluten content,and QSC-J-3B related to starch content.5.By comparing and analyzing the main effect QTL and stable QTL detected in the two RIL populations with the previous results,14 QTL were finally identified as newly discovered stable QTL,namely QGL-S-7D,QGW-S-2D,QTGW-S-6A-2,QKA-S-7D.1,QKP-S-7D.1,QGW-J-1B.2 and QGLWR-J-1A,QGPC-S-5A,QWGC-S-5A,QSC-S-5A,QGPC-J-6A-2,QWGC-J-3B,QWGC-J-6A-2,QSC-J-3B related to quality traits..6.By analyzing the additive effect values of these newly identified stable QTL,The favorable alleles of QGL-S-7D,QTGW-S-6A-2,QKA-S-7D.1,QKP-S-7D.1,QGL-J-1A,QTGW-J-4D,QGLWR-J-1A,QKA-J-1B,QKP-J-6A-2 associated with grain traits and QGPC-S-5A,QWGC-S-5A,QWGC-J-3B associated with quality traits were all derived from the parent synthetic hexaploid wheat KU2039 and KU2098,and the results indicated that synthetic hexaploid wheat is of great value for the improvement of seed and quality traits in wheat. |
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