大豆疫霉Phytophthora sojae卵孢子在黑龙江省土壤中的越冬存活率

为探究大豆疫霉Phytophthora sojae卵孢子在黑龙江省土壤中的越冬存活率及其与所处土壤深度和媒介的相关性,以增强型绿色荧光蛋白为报告基因,将培养基及病残体中的大豆疫霉卵孢子分别接种到试验田框栽土壤表层下不同深处,检测其卵孢子的越冬存活率,同时在框栽中定量播种不含任何已知抗疫霉根腐病基因的大豆品种Sloan(rps),苗期调查其发病率。结果表明,大豆疫霉卵孢子在黑龙江省土壤中的适生性较强,可在5~15 cm深度土壤中安全越冬,越冬存活率高达81.67%~96.33%。卵孢子越冬存活率与其所处的越冬媒介关系不大,而与土壤深度有关。在5~15 cm范围内,随着土壤深度的增加,卵孢子越冬存活率增加。处于深层土壤中的卵孢子更容易打破休眠,进入萌发前的萌动状态。各处理间卵孢子越冬存活率的显著性差异并未在发病率上表现出来,说明除了土壤深度外,还有其它因素影响发病率。

Overwintering survival rate of Phytophthora sojae oospores in soils in Heilongjiang Province

In order to investigate the associations between the survival rate of overwintering oospores of Phytophthora sojae and the soil depth and media in which the oospores were in Heilongjiang Province. The oospores in the media and diseased soybean tissues were inoculated at different depths below the soil surface in experimental fields under natural conditions. Some samples were collected randomly to measure the survival rate of oospores under a fluorescent microscope. Meanwhile, the seeds of susceptible soybean cultivar Sloan containing no R gene (rps) to Phytophthora root and stem rot were planted quantificationally in the frames to measure the incidence at seedling stage. The results showed that the oospores of P. sojae could overwinter with a survival rate of 81.67%-96.33%, indicating that they were adapted to the soil environment in Heilongjiang Province. The survival rate of overwintering oospores was related to the soil depth where oospores located, and had little relationship with the media. With the depth increasing, the survival rate of overwintering oospores increased. Oospores that located in deep soils were more likely to break dormancy to germinate. The significant differences in the survival rate of overwintering oospores between different treatments did not express in the seedling incidence, indicating that, in addition to the soil depth, there were other factors influencing the incidence of this disease.