INHERITANCE OF GENETIC MALE STERILITY ( GMS ) AND ITS UTILIZATION IN RAPE (BRASSICA NAPUS L. )
Li Shilling,Zhou Xirong,Zhou Zhijiang,Qian Yuxiu ( Crop Breeding and Cultivation Research Institute, Shanghai Academy of Agricultural Sciences, Chin a )
It was found that GMS is controled by two dominant genes (Ms and Rf) with epistasis. The gene Ms is sterile. The gene Rf is fertile and dominance epistasis over the Ms. According to this principle of genetics, the genotype of sterile plants is Ms-rfrf and the genotypes of fertile plants are Ms-Rf-,msmsRf- and msmsrfrf. While the genotype of the fertile plants is RfRf as a restorer line. The fertile and sterile segregation ratio is 1 to 1 in the F, progeny got by sib-mating ( Msmsrfrf × msmsrfrf and MsMsrfrf × MsMsRfrf ) . The former ( Msmsrfrf × msmsrfrf ) is called heterozygous two-type line and the latter(MsMsrfrf × MsMsRfrf)is called homozygous two-type line.The method using the two-type line in crosses with the restorer line to produce hybrid seeds is called two-line method.Using this method to produce hybrid seeds, the 50% fertile plants must be rogued from the two-type line. If the sterile plants ( MsMsrfrf) cross with double recessive plants ( msmsrfr f), the F1 progeny is fully sterile.