Effect of rootstock on muskmelon cultivar reaction to vine decline disease and yield under arid conditions

Monosporascus cannonballus, Rhizoctonia solani and Pythium aphanidermatum are the main causal agents of muskmelon vine decline disease in Oman. This study was conducted to examine the response of six cucurbit rootstocks grafted on four muskmelon scions to the causal agents and fruit quality and quantity. The response of 10 day old Palmira seedlings to artificial inoculation with R. solani pathogen alone revealed more damage to muskmelon seedling whereas P. aphanidermatum and M. cannonballus caused less damage when inoculated singly but more disease severity index when combined with R. solani. Artificial inoculation of different rootstocks produced significantly no damping-off and very low vine decline disease severity index on Mubyeongjangsoo, Titan, Tetsukabuto, Rsscih7458, Ezra and Strong Tosa rootstocks. All rootstocks produced high grafting success and low graft failure with the four selected muskmelon cultivars. Rootstocks enhanced early harvesting of grafted Tamara but had no effect on other scions. Fruit shape was almost not significantly affected by grafting except Samit grafted on Strong Tosa and Caramel grafted on Mubyeongjangsoo produced significantly different fruit shapes compared to ungrafted controls in the spring 2013 trial. Fruits from both grafted Shahd and Tamara showed no significant differences in rind brightness, redness and yellowness from the control. An various effect of rootstock was found on harvesting, fruit number and weight, chlorophyll content, and stem diameter of the scion. Rootstocks enhanced early harvesting and increased fruit number and fruit weight in grafted Tamara scions. There was no significant effect of grafting on fruit TSS. The study shows positive effects of grafting on tolerance to vine decline and on fruit quality and yield.