Genetic analysis and fine mapping of Watermelon mosaic virus resistance gene in cucumber

Watermelon mosaic virus (WMV) is an important disease of cucumber (Cucumis sativus L.) that is difficult to control in the field. Some resistant lines are available, and understanding the inheritance of the disease and mapping the gene or genes that confer resistance will facilitate the development of further resistant varieties. In this study, the inheritance and gene mapping for resistance to WMV in cucumber were conducted using populations derived from the cross between susceptible '65G' and resistant '2245' inbred lines. Genetic analysis showed that resistance to WMV in '2245' is controlled by a single recessive gene designated as wmv(02245) mapped to chromosome 6 (Chr.6). The region was flanked by the molecular markers SSRWMV60-23 and CAPS-W1 with genetic distances of 0.34 and 1.19 cM from the wmv(02245) locus, respectively. The 134.7 kb physical distance of this region includes 21 candidate genes. Comparison of the genotypic and phenotypic results showed that the accuracy rate of the most closely linked marker SSRWMV60-23 was 94.0 %. This marker will be used for molecular marker-assisted selection to select resistant lines, and future research will be directed at identifying and cloning the resistance gene.