Fine Mapping of the Nuclear Fertility Restorer Gene for HL Cytoplasmic Male Sterility in Rice

Bulked segregant analysis (BSA) of a BC1 population derived from congguang 41A/MiYang 23//congguang 41B was used to map the nuclear fertility restorer gene Rf5 for HongLian (HL) cytoplasmic male sterility. The parents and two bulks representing extremely fertile and sterile plants, respectively, were screened for polymorphism with 20 microsatellite primer pairs on chromosome 10, chosen on the basis of previous research. MRG4456 is linked to the fertility restorer gene Rf5 at a distance of 1.57 cM, and another newly developed microsatellite primer, HL01, was locked at a distance of 0.63 cM to Rf5. Closely linked DNA markers will facilitate not only breeding but also the purity management of hybrid seeds. Concrete steps for developing new microsatellite markers using the rice whole genomic sequence database are also described.