依据土壤环境因子对油菜根肿病发生的风险评估

为了解土壤环境因子对根肿病发生的影响,2012年-2013年从我国油菜主产区采集土样12份,在实验室接种根肿菌(Plasmodiophora brassicae)后播种北京新三号(高感白菜品种)。实验结果发现:湖北随州和安徽巢湖土壤样品在根肿菌孢子接种量(按每克土壤中的孢子数量计算)为103接种时发病率达到76.7%;而湖北武昌和阳逻、青海西宁和互助、甘肃民乐等地土样在接种浓度为105时发病率仅为0~3.3%。说明湖北随州和安徽巢湖根肿病发生风险高,湖北阳逻和武昌、青海西宁和互助以及甘肃民乐根肿病发生风险小。土样灭菌后进行接种实验和对土样的理化性质和营养成分进行分析,初步明确在一些土壤中存在土壤生物因子抑制根肿病发生;使用SPSS软件进行路径分析发现,p H、速效钙、全磷、全钾和阳离子交换量(CEC)等因素对根肿病发病率具有抑制作用。

Risk assessment of clubroot on the basis of environmental effect factors in soil

 To understand the risk of rapeseed clubroot in different soil environments, 12 soil-samples were collected from main rapeseed production areas in 2012 to 2013. Plasmodiophora brassicae were inoculated on high susceptive Brassica rapa cv Beijingxin 3 for club root risk assessment. Results showed a significant relation between disease incidences and sampling location. The disease incidences were up to 76.7% on samples from Suizhou of Hubei Province and Chaohu of Anhui Province under the resting spore concentration of 103 spores per soil gram. On the contrary, the disease incidences were as low as 0-3.3% in soils from Wuchang and Yangluo of Hubei Province, Xining and Huzhu of Qinghai Province, Minle of Gansu Province, even under the inoculation density of 105 spores per soil gram. It suggested that clubroot risks were high in the soil from Suizhou and Chaohu, and low from Wuchang, Yangluo, Xining, Huzhunghai and Minle. Some soil factors were found inhibiting the disease after inoculation tests on sterilized soil samples. The correlation of environmental factors in soils and clubroot incidence were determined by path analysis using the statistical analysis software SPSS (statistical product and service solutions). Results showed that pH, available calcium, total phosphorus, total potassium and cation exchange capacity (CEC) were negatively related with clubroot incidence. These results could benefit the development of clubroot management strategies in effective prevention of clubroot disease.