玉米灰斑病菌致病性的稳定性研究

The Stability of Pathogenic of Gray Leaf Spot Pathogens

采用连续脱离寄主继代培养的方法研究了玉米灰斑病菌的稳定性,利用寄主与病原菌交叉接种方法检测菌株对寄主的适应性。结果表明:玉米灰斑病菌通过多代无性繁殖可在一定程度上改变病菌培养性状或降低致病能力,但这些差异积累还未达到可转变为另一致病类型程度,说明病菌致病类型的转变需要与寄主更多的世代互作;多数供试菌株对来源品种具有较高的适应性,其致病活性明显高于在异源品种上的侵染能力,说明在某一地区病菌与寄主长期互作过程中形成适应性变异,对寄主的亲合能力明显增强,因此,一个地区不适宜长期单一种植某一品种,否则容易引起病菌发生适应性变异,导致品种抗性丧失。

The stability of GLS （Gray Leaf Spot） pathogens obtained through continuous isolates growing on medium for multi generation and adaptivity of pathogens on hosts obtained through inoculation with isolates and cultivars from different region were studied in this article. The continuous cultivation can change cultural characteristics and pathogenicity of GLS pathogens. But these isolates not become other pathogenicity types. The change of pathogenecity groups demands more interaction between pathogens and hosts. The adaptivity of many isolates on source hosts was higher. The long-term interaction between pathogens and hosts in somewhere can become adaptive variation and amplify affinity to hosts. A single cultivar not cultivates in an area for ages. Otherwise it easily becomes adaptive variation of pathogens and resistance deprivation of cultivars.