Trial Planting And Study Of The Key Cultivation Techniques For Vegetable Sweet Potato Varieties Introduced To Hainan

This study chose 10 fine varieties of vegetable sweet potato as experimental material.We conducted trial planting experiments and studied the key cultivation techniques that would affect their growth in Hainan area, including cold resistance and fertilization. This study tried to find out the suitable varieties for cultivation in Hainan area and provided some enlightens for the key cultivation techniques dedicated for high yield and good quality. The results are as follows:(1) Trial planting of the 10 varieties of vegetable sweet potatoThe trial planting of the 10 varieties of vegetable sweet potato showed that Xu caishu1,65-6, Pushu 53 and Hainan local varieties have stronger growth potential. The comparisons on the yield and quality showed that Xu caishu 1, Pushu 53 have higher yields and good quality, indicating they might be suitable for planting in Hainan area. In the test for cold resistance, Pushu 53 has stronger performance with excellent yield and quality, indicating Pushu 53 as the most suitable variety for winter cultivation in Hainan area.(2) Effects of exogenous EBR on the physiological and biochemical characteristics of vegetable sweet potato.The variety of Xu caishul was used as experiment material. Spraying of exogenous EBR on Xu caishu 1 showed that the treatment of O.lmg/L EBR spraying were the most effective under cold stress. Within 48 hours of cold stress (8℃), the resistance indexes were better in the EBR spaying group than those of the control group without spaying. The resistance indexes included the activity of three anti-oxidase (CAT, POD and SOD), the content of osmotic adjustment substances (SP, TSS and Pro), MDA content and the relative electrical conductivity. The results showed that application of exogenous BR can significantly improve the cold tolerance of vegetable sweet potato.(3) Effects of fertilization on the growth of vegetable sweet potatoThe variety of Xu caishul was used as experiment material. By using the uniform design method,the effects of nitrogen, phosphorus, potassium and selenium fertilization levels on yield and quality of vegetable sweet potato were estimated. The results showed that the yield of stem tip was the highest when the application of nitrogen fertilizer,phosphate fertilizer, potassium fertilizer and selenium were 11.3kg / 667m2, 7.6kg / 667m2 and 6.8kg / 667m2 and 0.014g / m2 respectively. That is, the ratio of N, P and K as 11.3:7.6:6.8 would be the most suitable in the cultivation of vegetable sweet potato, with good growth state and high expected yields.(4)The effects of nitrogen application on yield, nutrient quality and nitrate accumulation after harvestingThe variety of Xu caishul was used as experiment material. The effects of nitrogen fertilizer on the yield and quality of stem tip were studied by single factor random block design method. The results showed that the content of protein and nitrate in vegetable sweet potato increased significantly with the increase of nitrogen application level.Vitamin C, total sugar, polyphenols increased at first and then decreased, reducing-sugar content was declining. The leaf color value was significantly correlated with the protein, and the nitrate content was significantly correlated with the content of reducing sugar. The application of 5kg / 667m2 resulted the best quality of the sweet potato. After the application of nitrogen fertilizer, the nitrate content in the sweet potato reached the maximum at about 7days, and then decreased continously until at about 11 days, when it would declined to the level of control group without nitrogen fertilizer.