水稻品种多样性田间稻瘟病菌群体遗传结构分析

利用稻瘟病菌的一段倒位重复序列Pot2设计的一对引物，采用rep—PCR分子指纹技术对来自石屏县净种杂交稻田块、净种糯稻田块以及间种杂交稻糯稻田间的251个稻瘟病单孢分离菌株进行扩增．结果表明，所有供试菌株均分别扩增到9—17条DNA带，大小从400bp到23kb左右，但大多数带主要集中在5—10kb之间．所有菌株共扩增出的DNA指纹带中，约65％的为多态性DNA带，35％的为共同扩增带．将供试菌株扩增带诺进行聚类分析，比较间裁与净载田间病菌群体遗传结构的组成差异结果表明，在不同遗传相似水平，菌株遗传宗群复杂度与栽培方式有一定相关性。间栽田间病菌遗传宗群较净栽田问复杂，为3—5个，且优势宗群群不明显；而在净栽糯稻或净栽杂交稻田间遗传宗群较为简单，只有1—3个，且优势宗群明显．本试验结果证明水稻品种多样性有利于稻瘟病菌稳定化选择。

Annalysis of genetic structure of Magnaporthe grisea in the fields of different rice varieties

The DNA of 251 Magnaporthe grisea isolates from Shiping County, which originated from monoculture and mixture fields, was extracted and amplified by rep-PCR which primer was from palindromes Pot2 of Magnaporthe grisea. The result showed that all isolates were amplified 9-17 DNA bands, the size was about from 400 bp to 23 kb, but mainly between 5-10 kb. 65% bands were polymorphism bands, and 35% were the same bands. Genetic structures of Magnaporthe grisea in the different rice varieties fields were compared by clustering analysis. The complexions of isolates genetic lineages were related to culture patterns. There were more genetic lineages in mixture field than in monoculture one. The dominant lineages were not distinct in mixture field. The result proved that biodiversity might provide a convincing basis for the steady selection of rice variety to pathogen.