Greenhouse Evaluation of Melon Rootstock Resistance to Monosporascus Root Rot and Vine Decline as Well as of Yield and Fruit Quality in Grafted ‘Inodorus’ Melons

Melons (Cucumis melo L.) are generally grafted onto Cucurbita rootstocks to manage soilborne pathogens such asMonosporascus root rot and v ine decline (MRR/VD ) and Fusarium wilt. However, g rafting onto Cucurbita rootstocks reportedlyresults in the reduction of fruit quality. In this study, the resistance to MRR/VD, yield, and fruit quality of melons grafted ontomelon rootstocks were evaluated under greenhouse conditions. Eight melon rootstocks (R1 to R8) were used and the inodorusmelon ‘Homerunstar’ was used as scion. Melon rootstocks R1 to R6 were selected based on resistance to MRR/VD under greenhouseconditions. Non-grafted ‘Homerunstar’ and plants grafted onto squash interspecific hybrid ‘Shintozwa’ rootstock (Cucurbita maximaD. × C. moschata D.) served as controls. Grafted melons were cultivated in the greenhouse infested with Monosporascus cannonballusduring two growing seasons (summer and autumn). The responses to MRR/VD, yield, and fruit quality differed depending onthe rootstocks and growing season. The melons grafted onto ‘Shintozwa’ exhibited less severe disease symptoms and highersurvival rates than non-grafted melons in both seasons. While the melon rootstocks in the summer cultivation did not increasethe survival rate compared to non-grafted melons, the melon rootstocks R1 and R2 in the autumn cultivation led to highersurvival rates. The melon rootstocks resistant to MRR/VD increased the percentage of marketable fruits and marketable yields. Grafting onto the melon rootstocks caused little or no reduction of fruit quality such as low calcium content, fruit softening,and vitrescence, especially in lower-temperature autumn season. Accordingly, these results suggest that grafting onto the melonrootstocks may increase the tolerance to MRR/VD and the marketable yield without a reduction of fruit quality. KCI Citation Count: 3