Pesticides Could Alleviate the Symptoms of Sweet Potato Virus Disease(SPVD)

In recent years, sweet potato virus disease （SPVD） has severely affected the production of sweet potato in China. In order to select chemical agents to prevent sweet potato from being infected with SPVD, 14 pesticides were sprayed on the plants of sweet potato infected with SPVD, and the relative mRNA level of the viruses in the leaves and physiological indicators of sweet potato plants were detected. The results showed that after the application of most of the pesticides, the relative mRNA level of the two viruses that caused SPVD decreased, and the chlorophyll content and biomass of sweet potato infected with SPVD increased significantly or extremely significantly. Among the pesticides, BASF virus liquid, 0.1% physcion and Aolike powder for cucumber virus were proved to be the best, as the chlorophyll content and stem length of sweet potato increased significantly. The experiment indicated that the pesticides could reduce the harm of SPVD to sweet potato.

Effects of Growth Period on Quality and Tuber Traits of New Sweetpotato Cultivar Xuzishu 8

Xuzishu 8 is a new cultivated sweetpotato with high anthocyanidin content.The growth period affects its tuber traits and quality.In this study,the changes in sweetpotato shape,number of tubers per plant,rate of big and medium tubers,yield,anthocyanin content and starch content of Xuzishu 8 were investigated under 12 growth periods from 78 to 188 d.The results showed that various traits of Xuzishu 8 were significantly different between different growth periods.The rate of large and medium tubers,the fresh sweetpotato yield,the starch content and the anthocyanin yield increased gradually with the extension of the growth period.The length/width ratio of sweetpotato tubers,the rate of small tubers and the contents of reducing sugar and soluble sugar decreased with the prolongation of the growth period.The correlation analysis showed that the fresh sweetpotato yield was in significant or extremely significant positive correlation with the number of tubers per plant,rate of big and medium tubers,dry matter content,dry yield and starch content.The 148-day growth period treatment exhibited the highest number of tubers per plant,the highest fresh sweetpotato yield and anthocyanin yield reaching 3 927 and 4.25 kg/667 m^2,respectively,as well as the rate of large and medium tubers up to 90%.Therefore,the tubers had good marketability and eating quality.