Mapping and Genetic Characterization of Loci Controlling the Restoration of Male Fertility in Ogura CMS Radish

Three Raphanus populations (BC1, F2 and R8) each segregating for the restoration of Ogura CMS were used tomap restorer loci. The three restorer loci, Rf1, Rf2 and Rf3, each exhibited dominant restoring alleles and wereeach mutually epistatic. Rf1 was mapped to the upper region of Rs1 using data from each population. Rf2 wasmapped to the middle of Rs2 using both the F2 and R8 populations. Rf3 was mapped to the upper region of Rs7using the R8 population. The marker analysis and linkage mapping of the BC1 and F2 populations were describedpreviously (Bett and Lydiate, 2003). Scoring at 114 marker loci in R8 population allowed a new map ofthe Raphanus genome to be integrated with the consensus map. The complex genetic control of the restoration ofOgura CMS in Raphanus is compared with the more simple genetic control of this trait previously described inB. napus. Markers linked to each of the three restorer loci will allow the routine generation and verification ofdefined restorer and maintainer lines for various combinations of defined restorer loci. Although the restorationof Ogura CMS in Raphanus probably involves additional loci, the identification of three loci and diagnosticmarkers for each provides a solid foundation for the development of a holistic model for the genetic control ofthis trait through mapping in additional populations.