广东稻瘟病菌的遗传宗谱与致病性的关系

不同病圃同一套寄虫主的田间表现及其穗颈瘟分离菌株的遗传宗谱和致病性分析试验结果表明，不同生态稻区稻瘟病菌的小种分布类型不同，对品种的致病性也存在差异。将已经过ＲＦＬＰ和ＰＣＲ技术进行ＤＮＡ指纹分析，并划分为不同遗传宗谱的稻瘟病菌株进行致病性测定。结果表明，菌株的致病性与其遗传宗谱类型、生理小种类型、寄主及采集地点存在密切的关系：（１）同一遗传宗谱、分离自相同寄主、鉴定出来的生理小种类型又较接近的菌

PRELIMINARY STUDY OF THE RELATIONSHIP BETWEEN GENETIC LINEAGE AND PATHOGENICITY OF MAGNAPORTHE GRISEA

The distribution of physiological races of rice blast was tested on the same set of hosts in different nurseries as well as the genetic lineage and the pathogenicity of the blast isolates. The results indicate that the distribution of races was different and so was the pathogenicity to rice culti-vars. There was close relationship between the pathogenicity of the blast isolates and their genetic lineage, type of races, host and the site of collection presented by the result of the pathogenicity test of the isolates that were divided into different types by RFLP and PCR finger printing. (1) The isolates from the same genetic lineage and isolated from the same host with close related race types showed highest similarity in pathogenicity. (2) Isolates fell into the same genetic lineage and collected from the same site presented higher rate of similarity even if they were not from the same host. (3) The pathogenicity of isolates tested as different lineage and collected from different hosts differed greatly. When selecting rice blast isolates for identification of cultivar of germplasm resistance, the pathogenicity identified by differential hosts must be combined with the DNA finger printing of isolates, host and collecting site so that the reliability and the representative of the isolates could be ensured.