The Investigation Of Seed Zucchini Virus Disease And Identification And Detection Of Its Viruses In Northern Xinjiang

The seed zucchini industry is one of the emerging industries that have the vast development potential in Xinjiang, which has played a major part in local farmers’ earnings and the regional economic development. Virus disease has become a common disease in the field, which has seriously affected the economic losses. Therefore, through investigating and researching on virus disease of seed zucchini, a theoretical basis for prevention and treatment of virus diseases could be provided for production and further research.Seed zucchini virus diseases were investigated regularly in the six different regions which the virus disease of seed zucchini had become common.The result showed that the virus diseases of seed zucchini in 2015 occurred later in general; the first occurred in late June, the latest occurred in July. The virus disease occurred from late June, and up to the peak in late August; the virus disease symptoms of seed zucchini were grouped into four categories: mosaic(M), yellow(Ye), malformation(Ma), fern leaves(Fl) and complex type, in which the most common type was mosaic, but the infection rates and indexes of virus disease of seed zucchini is different. It showed that the virus disease symptoms of seed zucchini were same, and there were significant difference in disease degree in the different places.In order to understand the occurrence of seed zucchini virus diseases in seven regions in Xinjiang, collected 121 samples of seed zucchini were detected by using RT-PCR with 7 pairs of specific primers. The results showed that the four viruses were detected by PCR which was Cucumber mosaic virus(CMV), Zucchini yellow mosaic virus(ZYMV), Watermelon mosaic virus(WMV) or Papaya ringspot virus(PRSV-W), respectively. The detection rate of CMV, ZYMV, WMV and PRSV-W were 68.6%, 95.0%, 81.0% and 28.1%, respectively. In the field, all of the samples were infected with 2 or more viruses with the rate of 90.1%, and the mixed infection of ZYMV with other viruses(CMV, WMV+PRSV-W, CMV+WMV+PRSV-W) were the crucial problem in seed zucchini.To determine whether seeds of seed zucchini are infected by viruses, the seed-borne virus rate were detected by the multiplex RT-PCR. In the same time, to screen the efficient elimination method, virus elimination efficiency was evaluated with moist and dry heat treatments under different temperatures by relative quantitative method using fluorescence real-time RT-PCR. The result showed that seeds of seed zucchini were infected by CMV, ZYMV and WMV, and the detection rates were 67.1%, 50.0% and 72.3% respectively, while the composite detection rate was 66.0%. Different varieties of seeds had different virus detection rates, the lowest ratio was Lifeng-9(60%) and the highest were Jingfeng-9, Ruifeng-9, Lvfeng-9 and Jinhu360(100%). The temperatures of wet and dry heat treatments had some influence on seed-borne virus rate, Dry heat treatments had the highest virus elimination rate for WMV and CMV at 60℃ and 70℃, so did the wet heat treatments for ZYMV at 75℃.