Construction Of Chromosome Segment Substitution Lines Harboring Oryza Longistaminata Genome And QTL Mapping For Several Agronomic Traits In Rice(Oryza Sativa)

Under the long-term survival competition and natural selection,wild rice and its related species have accumulated a large number of favorable genes,such as disease resistance,insect resistance,stress resistance,male sterility and strong regeneration genes,which are natural rice gene pools.Chromosome segment substitution lines(CSSLs)are important genetic materials for exploiting and utilizing beneficial genes in wild rice.By constructing CSSLs with wild rice as donor and cultivated rice as recipient,the conditions for further excavation and identification of excellent genes in wild rice can be created.In this study,a set of CSSLs has been developed through backcross,self-crossing and molecular marker-assisted selection(MAS)by using Oryza longistaminata as the donor parent and elite cultivar,Huang HuaZhan,as the receptor parent Meanwhile,QTLs of significant agronomic traits were identified based on the CSSLs.The main results were as follows:1?Based on sequence comparison between indica and japonica,we developped 743 SSR molecular markers.And there were 156 polymorphic markers between parents.The frequency of polymorphism was 20.99%.In the relatively sparse region of the chromosomes,we designed 143 Oryza longistaminata specific InDel markers.And there were 34 polymorphic markers between parents.The frequency of polymorphism was 23.78%.The average number of polymorphic markers on each chromosome was 15.8,and the average physical distance between adjacent molecular markers was 1.95 Mb.2?Atotal of 37 CSSLs harboring Oryzalongistaminata genome have been developed using the 190pairs of polymorphic markers evenly distributed on 12 chromosomes of rice.A total of 308 fragments were carried in these CSSLs,with an average of 8.32 substituted fragments per line and 25.6 substituted fragments per chromosome.The average length of substituted segment was 2.81Mb and the total coverage length of substituted segments was 272.98Mb,which was equal to 76.63%coverage of the whole rice genome.3?The 3 7 CSSLs was employed to evaluate the twelve major characteristics,including plant height,length of flag leaf,width of flag leaf,flag leaf area,panicle length,number ofprimary branch per panicle,grain number,percent seed set,grain width,grain length,ratio of grain length with width and 1000-grain weight.Based on the comprehensive analysis,there were significant correlations among the traits.Besides,all the traits exhibited continuous normal distributional,which suggested that these traits were quantitative traits and controlled by multiple genes.4?Atotal of 42 QTLs for 12 main agronomic traits were detected in 37 CSSLs except the trait of 1000-grain weight Seven QTLs for plant height were identified on chromosome 1?3?7 and 12 in rice,with the range of individually explaining phenotypic variation being from 8.01%to 11.51%and additive effects ranging from 12.07 to 22.92.5?One QTL for length of flag leaf,one QTL for width of flag leaf and one QTL for flag leaf area were detected on chromosome 1 and 9 in rice.The individually explaining phenotypic variations were 35.65%,29.75%and 37.51%,respectively.The additive effects were 4.11?0.19 and 7.12,respectively.6?Fifteen QTLs controlling panicle traits were identified on chromosome 1?3?4?7?8?9and 12 in rice.Four QTLs for panicle length were detected,with the individually explaining phenotypic variation ranging from 9.97%to 20.50%and additive effects ranging from 12.07 to 22.92.Three QTLs for primary branch number were detected,with the individually explaining phenotypic variation ranging from 17.01%to 29.39%and additive effects ranging from 1.91 to 4.70.One QTL for grain number per panicle was detected Seven QTLs for seed setting rate were detected,with the individually explaining phenotypic variation ranging from 8.00%to 14.77%and additive effects ranging from-0.31 to-0.08.7?Seventeen QTLs for grain type were identified on chromosome 1?2?5?8 and 12 in rice,among which eight QTLs were found to control grain width,with the individually explaining phenotypic variation ranging from 7.5%to 11.83%and additive effects ranging from 0.13 to 0.31.Two QTLs were detected to control grain length,with the individually explaining phenotypic variation of 15.13%and 17.78%,additive effects of-0.30 and-0.41,respectively.Eight QTLs were detected to control ratio of grain length with width,with the individually explaining phenotypic variation ranging from 8.01%to 11.87%.The additive effect ranged from-0.33 to-0.24.