The Dynamics Of Sporangium Of Plasmopara Viticola And Resistance Of Different Grape Varieties In Shihezi Region

The results showed that the incubation period for P.viticola is about 4-6 days,and if the environment is_suitable,the disease will occurrence and pandemic.Spatio-temporal distributions of Plasmopara viticola were monitored by spore-trapping,and their relativity with disease levels in vineyard were analysed.The founding showed that a majority of sporangia flew within the vine canopy,and most near the ground.The number of sporangia reduced by the height increasing above canopy. The Daily dynamics of sporangia revealed that sporangium can be captured within 24 hours of a day, and has dual-peak at 8.0am and 8.0pm, higher at 8.0pm.The dynamics of sporangium has positive correlation with temperature,and negative correlation with humidity and rainfall.The result of spore-trapping in there years displayed d that the dynamics of sporangium of Plasmopara viticola has multi-peak,there is significant positive correlation between the number of sporangia and disease index after 5 days in p< 0.01 level.Sporangia of P.viticola were observed in early June, its epidemic period was June to September, and its peak obtained at last July to early September, accompany slope down in Shihezi region. By consecutive observation of 2008-2010 three years,From the appearance of sporangia,if the conditions is right,the disease will occurrence,and at the sporangia catching peak,if the climatic conditions appropriate,the disease will spreaded rapidly in 4-6 days.Through the identification of disease resistance in field surveys indoor and outdoor, itwas demonstrated that in seven tested varieties, Krison and Flame seedless is more resistant to P.viticola, whereas Red Globe grape, Centennial Seedless, Seedless spurple, Zixiangwuhe and Rizazet are susceptible or higlysusceptible. Accounting spores of single spot of infected leaves, the size of disease spots of Krison and Flame seedless is small, and the number of spores in single spot is few, while the susceptible or higlysusceptible variety has opposite results. The observed result under scanning electron-microscope revealed that the stomata of Krison and Flame seedlessis smallest, and the number of stomata is fewest.however the stomata of Rizazet is biggest,and the number of stomata is maximum.Therefor, preliminary think that the stomata of resistant cultivar fewer and smaller, while the susceptible ones is large and dense.The result from DPS software showed that the temperature in July and rainfall in August were the main factor which influence the disease severity, and then established the discriminant model, the accuracy of the data for back-test 100.0%. The analysis results between the occurrence of downy mildew of grape and meteorological data showed that the disease has positive correlation with rainfall and humidity,and negative correlation with temperature. Meanwhile, initial period of grape downy mildew is associated with meteorological of early June and middle of June.