Occurrence And Control Strategies Of Sweet Potato Virus Disease In Fujian Province

Sweet potato is the second place of food crop in Fujian province, plays an important role of our food security. But there are more than 30 viral diseases constrain the production of sweet potato, among them, the sweet potato virus disease (SPVD) caused by two kinds of virus together, SPFMV and SPCSV, is specially serious and may cause yield loss more than 90%. Occurrence of virus disease in different areas in Fujian province and different seasons, different cultivars and different parts of the sweet potato plant were investigad, the development and distribution of virus disease of sweet potato in Fujian province were analyzed, the relationship of SPVD development and the expression of key gene RNase3 of SPCSV was studied. On the basis of the results, the strategies of control for the sweet potato virus disease in Fujian province were proposed. The main results are as following:1. The survey found that there were eleven virus infected sweet potato in Fujian province including SPFMV, SPCSV, SPVC, SPVG, SPV2, SPLV, SPVMV, CMV, SPLCV, SPPV and SPSMV-1. The SPFMV and SPSMV-1 were most common virus while CMV was at least common in Fujian province.2. The eleven kinds of virus dectected were analyses by comparing the special sequence of virus with those from gene bank, the results indicated that SPFMV in Fujian province belongs to EA strain, SPCSV belongs to WA strain. There were different strain of SPV2, SPVC, SPVG. The sequences showed high homology between SPLV and Chinese strain, CMV and DZ-2 strain, SPLCV and SPLCV-MEX strain, SPVMV and Hennan strain,SPPV and SPMSV-1.3. There were different intensity extents damaged by virus disease in different sweet potato production regions in Fujian province. There were most serious in Quanzhou, Fuzhou and Putian region, while there were less serioius in Sanming and Longyan region. Ten kinds of virus were detected in Fuzhou region, nine in Quanzhou region, senen in Putian region, nine in Sanming region and three in Longyan region.4. There were different intensity extents damaged by virus disease in different seasons. There were most serious in seedling stage, in which there were varied from 0 to 6 kinds of virus were detected among different cultivars. There different concentrations of virus accumulated in different parts of sweet potato plant.5. Complex infection was the most common pattern of virus infection in sweet potato in Fujian province. SPV2, SPSMV-1 and SPPV were found to infecte sweet potato alone, but the rest of virus were found complex infection, which accont for 80.49%; SPVD would most likely to develop when infected by SPFMV with SPCSV together.6. Transmiting of SPVD was studied by grafting and feeding by insect as intermediary, confirmed that the SPVD could be transmited by contacting of juice and by feeding of insect. The relationship of expression of RNase3 gene in SPCSV and the development of SPVD was studied, indicated that the RNase3 gene was a key factor influence the developing of SPVD.7. According to the results of investigation and study above, the strategies of control for the sweet potato virus disease in Fujian province were proposed, Including strengthening introduction of quarantine for sweet potato, preventing virus being spread; Strengthening field management, controlling of the insect in the field, getting rid of the disease plant in time; developing new cultivars with resistance to sweet potato varieties, and extending application of virus-free sweet potato.