Effects Of Different Rootstocks On The Growth And Quality Of Grafted Watermelon

Watermelon is a kind of important horticultural in the world.However, continuous cropping plant during many years. Serious problems of watermelon production such as soil-borne disease, in particular fusariumand successive cropping. Grafting is an effective measure to prevent watermelon from soil borne disease grafting can increase resistance of watermelon meanwhile,it impacts on watermelon growth and fruit quality, and the different root stock/scion combination is effects differently. Zaojia8424was used as scion. Jing Xin No.1, Qing Yan1and Yong Shi were used as rootstocks in this test. Studying on the effects of different rootstocks on growth and fruit quality. Results are as follows:1. Studying on the effects of different rootstocks on mineral composition of scion growth, dry matter accumulation and all tissues at different stages came to the results that: grafted plant took obvious advantages in the aspects of plant height, stem diameter and leaf area during fruit mature period, in particular Qing Yan1. Mineral composition of roots, stems, leaves, fruits and peels had significantly affected by rootstocks. Mineral composition of different tissues was changed by different growth stages. As a whole, Decrease in total mineral composition of grafted plant with Jing Xin No.1was reported at vegetative stage while increase in composition of grafted plant with Qing Yan No.1. When it came to reproductive stage, mineral composition of grafted plant with Jing Xin No.1increased and there was no difference with own-rooted plant regards to mineral composition. While grafted plant with Qing Yan No.1had significantly higher content of mineral composition than both grafted plant with Jing Xin No.1and ungrafted plant. Analysis of nutrients concentration of N, P, K came to a conclusion that highest K concentration was determined in both grafted plant and own-rooted plant while the lowest P was recorded, concentration of N was between the above two. There was a significant guide for agricultural production in severely fertilizing N composition while neglecting P and K composition. 2. It conducted the differences of root parameters, bleeding, composition of roof bleeding sap, the growth of plant morphology under substrate culture with different rootstocks. The results showed that:Grafted watermelons with rootstock were superior to those of own-root on the aspects of fresh weight, length, volume and absorption area of their roots. And the composition of roof bleeding sap had obviously increased with different rootstocks. Compared with own-root watermelon, every part of bleeding had risen substantially with " Jingxinzhen1" and " Warrior". Free amino acid content in the root stock bleeding SAP has sharply decline in "Qingyan1". But Above ground growth strongly after grafting. The results indicate that the watermelon absorption of nutrients is closely related to root morphology. But different combination effect is disaccord3. Studying on the effects of different rootstocks on the photosynthesis of watermelon, leaf physiological indexes and stoma in fruit mature period. The results showed that:With the observation of " Jingxinzhen1" and "Warrior" as grafting rootstock, it had obviously increased in aspects of net photosynthetic rate, stomatal conductance, transpiration rate. Besides, it had relevantly improved in terms of light saturation point, apparent quantum yield, and maximum photosynthetic rate, as well as in contents of chlorophyll and soluble protein in the leaves. Meanwhile, It also enhanced stomatal density and the width of stoma.4. The influence of different rootstocks on the process of dynamic development and fruit quality of grafted watermelon was studied. The results showed that different rootstocks had different effects on sugar accumulation of watermelon. Using Jingxinzheng No.1and wild watermelon Yongshi as rootstocks could improve the content of sugar in watermelon fuit. The content of sugar decreased using pumpkin as rootstocks, but in the late, it increased, and finally reached the equivalent level to the non-grafted. Yongshi and Jingxinzheng No.1promoted the unloading of sugar, and co u Id efficiently convert monosaccharides to sucrose in storage, thereby enhanced the accumulation of sugar。The capacity of sugar unloading decreased using Qingyan1, and the capacity of converting sucrose was weak in the late. The trend of key enzyme genes related to sucrose metabolism was not in conformity with sugar content and enzyme activity.Grafting can improve the content of lycopene in watermelon fruit.