Effect mechanisms of different grafting rootstocks on physiological wilt disease of watermelon.

【Objective】The experiment was conducted to study the effect mechanisms of different rootstocks on physiological wilt disease of watermelon in order to provide theoretical foundation for resistant rootstock screening and watermelon breeding. 【Method】Twelve different rootstocks of Lagenaria siceraria, squash, Benincasa and wild Citrullus vulgaris were selected to undergo the grafting test and filed cultivation test with seedless watermelon Guangxi 3. Physiological and biochemical indexes of watermelon leaves of different grafting combinations at later stage were determined. 【Result】The watermelon grafted with rootstocks of white seed pumpkin, Guangxi local cucurbit, cross cucurbit, Huoban wild watermelon, Japanese pumpkin, large white flowered gourd, and Chaofeng F1 generation showed low incidence rate of physiological wilt disease. The incidence rate was in 0-6.00%. The incidence rate of physiological wilt disease was the lowest when white seed pumpkin was used as rootstock. The chlorophyll a content, chlorophyll b content, total chlorophyll content, POD and SOD activity and free praline content were all significantly higher than the control, while the MDA content was significantly lower than the control. 【Conclusion】Four rootstocks viz., white seed pumpkin, Guangxi local cucurbit, cross cucurbit, Huoban wild watermelon showed stronger resistance to physiological wilt disease, therefore they could be applied to watermelon production.