Development Of Chromosome Single Segment Substitution Lines Using O.Nivara As Dornor And Identification Of Qtls For Main Agronomic Traits

During Long-term artificial selection, the diversity of the cultivated rice has reduced significantly, however, wild rice has reserved abundant variation and has formed strong adaptability for the change of environment in the process of natural selection.It was one of the important means to broaden the genetic basis of cultivated rice by mining the potential favorable genes from wild rice and apply them in the genetic improvement of cultivated rice. In this study, a set of chromosome single segment substitution lines(SSSLs) has been developed through backcross, self-crossing and molecular marker-assisted selection by using O. nivara Steud. as the donor parent and elite cultivar, HJX74, as the receptor parent. Meanwhile, QTLs of main agronomic traits were identified based on the SSSLs. The main results were as follows:1. A total of 174 homozygous chromosome single segment substitution lines have been developed, of which the substituted segment length was different. The total length of substituted segments was 2590.7 c M which was 1.69 times the size of the whole rice genome. The average length of substituted segment was 5.37 c M And the total coverage length of substituted segments was 935.15 c M, which was equal to 61.2% coverage of the whole rice genome.2. 100 QTLs of 14 main agronomic traits were detected in 65 single segment substitution lines. Among them, 7 QTL for length of flag leaf, 9 QTLs for plant height, 6 QTLs for spikelet setting density, 4 QTLs for number of panicles, 7 QTLs for number of primary branch per panicle, 3 QTLs for panicle length, 6 QTLs for percent seed set, 9 QTLs for 100-grain weight, 6 QTLs for width of flag leaf, 6 QTLs for grain length, 10 QTLs for IV grain width, 12 QTLs for heading date, 11 QTLs for grain width.In sum, a set of 150 chromosome single segment substitution lines of O. nivara have been developed and a batch of QTLs were detected based on the single segment substitution lines, which enriched the single segment substitution library in our lab. In the future, by using the SSSLs it would contribute greatly to fully dig the genes in O. nivara comprehensively, to analysis the function of genes in the further. It also laid the material foundation for applying favorites genes efficiently in the improvement of cultivated rice ultimately.