Effect Of Melon Interstock On The Growth And Fruit Quality Of Grafted Watermelon

Watermelon, which is rich in mineral salts and vitamins as can dispel summer heat, iswelcomed by the majority of consumers. Grafting, as an effective way in controllingsoil-borne deseases and overcoming the obtacles of continuous cropping in protected lands,has become an important technology for watermelon production in greenhouse. Graftinginevitably affects the fruit quality of watermelon, therefore, in order to reduce the impact ofrootstocks on fruit quality, breeding researchers have done a lot of work. Therefore, it isimperative to find a new way of grafting to improve the grafted watermelon quality and keepits resistance as well. In this test, in order to explore a concise and feasible way to improve thequality of grafted watermelon, we studied the effects of melon interstock on growth and fruitquality of grafted watermelon on the basis of traditional gafted watermelon.In this test, in order to provide the scientific basis for improve the grafted watermelonquality, we studied the effects of melon interstock on the growth development, the changes ofbleeding sap of watermelon plant and the fruit quality by using “JingXin No.2” watermelon asthe scion, the “Elisabeth” melon as the interstock, and “Degaotiezhu” pumpkin as therootstock. The main research results were summarized as follows:1.The plant of grafted watermelon with melon interstock can maintain the strong growthpotential of traditional grafted watermelon. Compared with self-root watermelon, the graftedwatermelon with melon interstock can increase the plant height, the stem diameter, thecreeper diameter significantly; can enhance the activities of absorbing root, as the root vigorwere23.9%,23.7%higher than that of self-root watermelon in the vigorous growth period;can raise the chlorophyll contents and the SPAD value, as the contents of chlorophyll were21.1%,19.6%higher than those of self-root watermelon; can enhance the photosynthetic rateand transpiration rate.2.The plant of grafted watermelon with melon interstock can enhance the ability towithstand adversity and delay senescence. In the vigorous growth period, the SOD, POD andCAT activities of grafted watermelon with interstock were higher than those of self-rootwatermelon among all treatments, and the vigor were ‘grafted watermelon with interstockwhich kept two true leaves’>‘grafted watermelon with interstock which kept no true leaves’>‘the traditional grafted watermelon’>‘the grafted watermelon with melon rootstock’>‘theself-root watermelon’; in the same growth period, the contents of MDA were ‘grafted watermelon with interstock which kept two true leaves’<‘grafted watermelon with interstockwhich kept no true leaves’<‘the traditional grafted watermelon’<‘the grafted watermelonwith melon rootstock’<‘the self-root watermelon’ in decreasing order; in the same growthperiod, the leaves of grafted watermelon with interstock had more osmotic adjustmentsubstance than ungrafted watermelon.3.Compared with self-root watermelon, the incidences of Fusarium wilt ofmelon-interstock grafted watermelon were57.2%,60.5%lower, but the survival rate ofmelon-interstock grafting were19.9%lower than that of traditional grafting.4.Compared with self-root watermelon, the longitudinal diameter of melon-interstockgrafted watermelon fruit increased16.8%,17.7%separately, as the horizontal diameterincreased18.2%,19.7%; the rind thickness of melon-interstock grafted watermelon was19.3%,21.9%lower than that of traditional grafted watermelon.5.The contents of soluble solids, solube sugar, Vc of intersock grafted watermelon weresignificantly higher than those in traditional grafted watermelon, whereas the nitrate andtitratable acid contents were lower than those of traditional grafted watermelon, and theintersock grafting can raise the soluble protein, free amino acids contens of the graftedwatermelon fruits; the lycopene content was not significant among the interstock graftedwatermelon, the traditional watermelon, and the ungrafted watermelon. Keeping two leaves ofthe melon interstock has more significant effects on the fruit quality of grafted watermelon.6.Interstock grafting can change the plant bleeding sap,and the bleeding sap can affectthe fuit quality. In the vigorous growth period, the bleeding sap content of grafted watermelonwith melon interstock were55.1%,46.7%higher than that of self-root watermelon plant, andthe solube sugar, soluble protein, free amino acids, nitrate contents in bleeding sap can affectthe contents of those in watermelon fruits.