The Heredity And Mapping Of The Male Sterile Gene In Thermo-sensitive Male Sterile Line (B.Napus)

Rapeseed is one of the important oil crops in China. Improving the yield and quality of rapeseed has always been the most important goal for the canola breeders. It had been proved that heterosis utilization can improve the yield of rapeseed. The discovery of ecotypical male sterility enriched heterosis utilization resources. This type male sterile line shows fertility and sterility in different conditions. When it is fertile, it can be used to reproduce itself, and when it is sterile, it can be used to product hybrid seeds. This type male sterile line does not need the maintain line, and it has more advantages than cytoplasmic male sterility and genetic male sterility.The materials used in this experiment were 261595 and 9535. 261595 was a new type of ecotypical male sterile line, and 9535 was a normal fertile material. Via the field experiment and growth chamber experiment, we studied the genetic of the male sterile gene, the critical sterility temperature and temperature-sensitive period of this type male sterile line. We used BSA method to screen the molecule markers, which linked to the male sterile gene, and we constructed a linkage map to map the male sterile gene initially. The main results are as following:1) The F₁ generation plants and reciprocal cross F₁ generation plants of 261595 and 9535 were sterile. The BC₁ population segregated at a 1:1 ratio for fertility/sterility, and the F₂ population segregated at a 2.73:1 ratio for fertility/sterility, following the segregation proportion of a single recessive gene. The results suggestted that the fertility of 261595 was controlled by a single recessive gene.2) We set 5 different tempretures to treat male sterile line 261595. In the 12℃and 14℃treatment, the flowers of 261595 were sterile. In the 16℃treatment, the flowers were not only sterile but also fertile. In the 18℃and 20℃treatment, the flowers were fertile. The results suggestted that 16℃was the fertility changing critical temperature of 261595. The temperature-sensitive time was 10 days before flowering.3) We selected extrem sterile plants from F₂ population, and we used the bulked-extrems and recessive-class approaches to map the sterile gene. We found 14 linkage markers, which were all located on the A10 linkage group of B.napus genome. The genetic map contained 41.9cM. The markers BrGMS564 and BrGMS881 showed the closest linkage to the sterile gene in the both sides, and the genetic distance was 1.1 cM and 0.6 cM, respectively.