Establishment of a detection method for soil plasmodiophora brassicae and investigation of rapeseed clubroot in Changde
Clubroot has caused serious harms to rapeseed and other cruciferous vegetables in China.The risk levels of clubroot in a field can be evaluated by detecting the concentration of Plasmodiophora brassicae spores which causes rapeseed clubroot.In this study,a real-time quantitative PCR(qPCR)method for P.brassicae quanti-tative detection was established.The method was validated by diseased rapeseed plants and rhizosphere soils of dis-eased plants from different areas in Hunan Province,and the results showed that the method has high sensitivity and specificity.This qPCR method determines that the threshold concentration of P.brassicae spores in soil for the oc-currence of clubroot is 1.34×103/g of soil.When the concentration of spores in the soil is higher than the threshold concentration,the risk of the occurrence of clubroot in rapeseed is higher.A field investigation was carried out in rapeseed planting areas of Changde,and 481 soil samples were randomly collected.The qPCR method was used to detect the concentration of P.brassicae spores in soil samples.On the basis of concentration of rhizome spores de-tected and the field clubroot investigation,it was found that rapeseed clubroot has developed at many points in Changde and has the trend of accelerating the spread.If effective control measures are not taken in time,the club-root will break out in a large area in Changde,which pose a severe danger to rapeseed production in Changde.For the rapeseed planting areas in Changde,the probability of occurrence of clubroot in fileds is low when no spores of P.brassicae or the spore concentration less than 1.34×103/g of soil have been detected,and non-resistant rapeseed varieties can be planted in these fields,but the disease in these fields should be monitored closely.Fields with spore concentration higher than1.34×103/g of soil need chemical prevention and control or planting of rapeseed varieties with resistance to clubroot.
万方数据
维普
