Chromosomal location and mode of inheritance of a gene conferring resistance to fusarium wilt in Cucumis anguria L.

Abstract

SummaryFusarium wilt of melon (Cucumis melo L.) is caused by Fusarium oxysporum f. sp. melonis and is considered a severe disease, worldwide. Resistant cultivars are effective in controlling such soil-borne diseases in melon. However, high resistance to F. oxysporum f. sp. melonis race 1,2y has not been found in any melon line, except recently, when it was reported in a wild Cucumis species which was regarded as a valuable genetic resource for breeding melon cultivars with high resistance. To plan an inter-specific breeding programme and to select resistant lines using marker-assisted selection, information on the mode of inheritance of resistance and linked markers are required. In this study, we developed F1, F2, F3, and BC1F1 lines from crosses between a highly resistant (R) and a susceptible (S) line of C. anguria. We evaluated the segregation of R and S phenotypes and constructed a linkage map using these phenotypes and simple sequence repeat (SSR) marker analysis. High resistance to F. oxysporum f. sp. melonis race 1,2y in C. anguria was proposed to be controlled by a single dominant gene named F1,2y for Fusarium oxysporum f. sp. melonis race 1,2y resistance. F1,2y was located on linkage group (LG) XI between the SSR markers ECM164 and CMN04_03. This is the first genetic study to report high resistance to F. oxysporum f. sp. melonis race 1,2y.