Development of RAPD and SCAR markers related to watermelon mosaic virus and zucchini yellow mosaic virus resistance in Cucurbita moschata

Squash (Cucurbita spp.) is a major vegetable crop in the Cucurbitaceae family, and has high economic value. Squash is an important foodstuff and has possible health benefits because of its antioxidant, anti-diabetic, anti-carcinogenic, and anti-microbial potential. However, the highly virulent watermelon mosaic virus (WMV) and zucchini yellow mosaic virus (ZYMV) are serious problems for squash worldwide. Single or mixed infections of WMV and ZYMV can destroy entire squash plants. Therefore, breeding squash cultivars with resistance to WMV and ZYMV is of major importance for squash cultivation. In this study, random amplified polymorphic DNA (RAPD) and sequence-characterized amplified region (SCAR) markers were developed using C. moschata lines resistant or susceptible to WMV and ZYMV. A total of 100 random primers were tested for their ability to discriminate between resistant and susceptible lines in RAPD analysis, and 4 RAPD markers (OPF10, OPF19, OPF20, and OPL19) related to WMV and ZYMV resistance were selected. Based on the RAPD results, genetic similarities were calculated and cluster analysis was conducted using unweighted pair group method with arithmetic mean (UPGMA) method. C. moschata lines were clearly segregated into resistant and susceptible lines by cluster analysis. One of the RAPD markers was successfully converted into a SCAR marker (VirSq-F19). This marker could be used as a tool for selecting WMV- and ZYMV-resistant squash in the early selection stages of a practical squash breeding program.