Development of RAPD Markers linked to Fusarium Wilt Resistance Gene in Castor Bean (Ricinus communis L)

Wilt, caused by Fusarium oxysporum f. sp. ricini, is the most severe disease of castor bean (Ricinus communis). For the development of marker for wilt-resistant gene, 200 F2 individuals from a cross between the resistant cultivar 48-1 and the susceptible cultivar VP-1 were inoculated with a race of Fusarium oxysporum f. sp. ricini. Bulked segregant analysis was used to search for random amplified polymorphic DNA (RAPD) markers linked to wilt resistance in F2 progeny derived from the above cross. Three markers (RKC 231375, RKC 211080 and OPBE 18900) flanking the wilt resistance gene were identified. The developed markers segregated from the screened Fusarium wilt resistant progenies of F2 and F3 families confirmed their linkage with Fusarium wilt resistance and the resistant castor bean genotypes were successfully identified among thirteen cultivars screened. Linkage analysis was carried out using the three markers on the 200 F2 individuals which showed that the genetic distance for the three markers at the wilt resistance gene was 5 cM, 10.7 cM and 7.6 cM respectively. The predicted protein 3D model of the translated amino acid sequence from RKC 23 showed characteristic features of DNA binding protein (2BIN). This study provides a base for probable mining of Fusarium wilt resistance gene in castor bean and simultaneously gives valuable insights into the characterization of R-gene subclass in castor genome.