Abstract: 【Objective】 The genetic mode of the recessive epistatic genic male sterile (REGMS) line 7-7365AB (Bnms3ms3ms4ms4RfRf/BnMs3ms3ms4ms4RfRf) was studied by molecular marker technology and backcrossing, self-crossing experiments. 【Method】 Two near-isogenic lines, 7-736512AB and 7-7365AC, which correspond to the BnMs4 gene and BnRf gene derived from a homozygous two-type line 7-7365AB, respectively, were constructed. Combined with BSA method, AFLP markers linked to the BnMs4 gene were identified, four of which were converted to SCAR markers, and genetic mapping of BnMs4 using published linkage maps of Brassica napus was conducted. Well-designed self-crossing and backcrossing experiments were conducted between the male sterile and fertile individuals from the 2 near-isogenic populations. The markers were also used to screen 176 accessions of breeding materials. 【Result】 Thirteen AFLP markers and four SCAR markers were identified linked to the BnMs4 gene. The BnMs4 gene was located in the top of the N7 linkage group, and was in the same region as the BnRf gene located previously. Comparison of both mapping results, six markers, CNU063, ENA06, sR4047, SC25, SC916, and SSR1, were common between the BnRf gene and BnMs4 gene. They were located in flanking sides of the two genes. The identical two closest markers flanking the BnMs4 gene and BnRf gene had genetic distances of 1.0 cM and 2.4 cM, respectively. Backcrossing and self-crossing experiments confirmed that the relationship between the BnMs4 gene and BnRf gene might not be independent assortment. Moreover, the analysis of 176 accessions did not show linkage-disequilibrium between the two genes. 【Conclusion】 The BnMs4 gene and BnRf gene might be multiple alleles.

Key words: Brassica napus, genetic marker, recessive genic male sterility, inheritance model