疫霉菌对霜脲氰抗性遗传及对霜脲氰和甲霜灵的交互抗性

Inheritance of the Resistance of Phytophthora spp. to Cymoxanil and Its Cross resistance to Cymoxanil and Metalaxyl

就疫霉菌对霜脲氰抗性的产生和遗传，以及疫霉菌对霜脲氰和甲霜灵的交互抗性进行了研究。结果表明，苎麻疫霉容易对霜脲氰产生抗药性突变，但抗性在连续３代单游动孢子分离过程中逐渐丧失。大雄疫霉对霜脲氰不易产生抗性突变，恶疫霉。

The isolates of Phytophthora boehmeriae and P megasperma were exposed to LBA agar amended with cymoxanil No cymoxanil resistant mutants were obtained in P megasperma In P boehmeriae, seven Cy rmutants of isolate JS2 from LBA agar amended with 50 μg/mL cymoxanil and one Cy rmutant of isolate JS5 from LBA agar amended with 100 μg/mL cymoxanil were obtained After subcultured in chemical free agar, only four Cy rmutants of isolate JS2 and one Cy r mutant of isolate JS5 could maintain the resistance to cymoxanil In the process of single zoospore isolated, the resistance to cymoxanil of Cy r mutants decreased gradually No obvious difference was found in the sensitivity to metalaxyl between Cy rmutants and their Cy rparents Similarly, no obvious difference in the sensitivity to cymoxanil between Mt rmutants and their Mt r parents The result suggested that no cross resistance between cymoxanil and metalaxyl in Phytophthora spp