Construction of an SSR-based Linkage Map and Mapping of the Restorer-of-fertility (Rf) Gene in Pepper (Capsicum annuum L.)

In pepper, cytoplasmic-genetic male sterility (CMS) system is very useful for commercial F1 hybrid seed production. Application of molecular markers to monitor the genes involved in CMS system can reduce the time of backcross breeding. Based on the potential utility of SSR markers, the purpose of this research is to construct an SSR-based linkage map of pepper and to map the nuclear Restorer-of-fertility gene. An F2 population consisted of 204 plants was developed as the mapping population. Progeny test was conducted to check the genotype of Rf gene and the phenotype was regarded as a codominant marker. The ratio of segregation of Rf gene is approximated to 1:2:1. The linkage map contains 112 SSR markers and covers 724.4 cM with 15 linkage groups. Compared with the reference genetic map, the linkages and orders of the SSR markers in this study were generally identical to the published maps. AFRF3CAPS, a published Rf-likned marker, is also linked to Rf gene in the study. Our LG6 where Rf gene is located corresponds to the chromosome 6 in a consolidated pepper map indirectly through a published SSR marker, Hpms1-5. However, the genetic distance between Rf gene and the nearest SSR marker, CM458, is 21.1 cM. The future works on this project is to saturate this linkage map by more SSR or SNP markers.