辣椒疫霉对双炔酰菌胺的敏感性测定及其 抗药突变体生物学性状研究

研究了辣椒疫霉对双炔酰菌胺的敏感性及其抗药性风险。采用菌丝生长速率法测定了分别采自河北定兴、藁城和山东寿光、青州等地的173株辣椒疫霉菌株对双炔酰菌胺的敏感性,结果表明,其EC50值介于0.002 7~0.049 9 μ g/mL之间,平均EC50值为0.021 9±0.010 2 μ g/mL,敏感性呈单峰曲线分布;采用紫外诱导+菌落角变和药剂驯化的方法分别处理10个供试菌株,各获得7株和1株突变体,其抗性倍数在41.50~394 437.77之间,突变频率分别为1.46%和1.43%。对突变体部分生物学性状的研究表明,抗性突变体与其亲本菌株在菌丝生长速率、致病性、产孢能力、适合度指数和竞争力方面均具有不同程度的差异;抗性突变体DX 2-3 20m和DX 2-3 F7的产孢量、适合度和竞争力均高于亲本菌株,有利于抗性群体的形成。研究表明,辣椒疫霉对双炔酰菌胺存在中等抗性风险。

Study on the sensitivity of Phytophthora capsici to mandipropamid and biological characteristics of resistant mutants

The sensitivity and resistance risk of Phytophthora capsici to mandipropamid were studied.The sensitivity of 173 P.capsici strains to mandipropamid was determined by mycelia growth inhibition method.The results demonstrated that EC50 values ranged from 0.002 7 μ g/mL to 0.049 9 μ g/mL,with a mean value of 0.021 9±0.010 2 μ g/mL.The sensitivity frequency of P.capsici to mandipropamid distributed as a single peak curve.The 10 strains were separately treated by UV- irradiating with colony point change and taming,with 7 and 1 resistant mutants to mandipropamid separately obtained in vitro by UV-irradiating and taming,the resistant levels ranged from 41.50 to 394 437.77 times.Mutation frequencies were 1.46% and 1.43%,respectively.Some biological characteristics of mutants were studied in laboratory.The mutants exhibited diversity in mycelial growth rate,pathogenicity,sporulation ability,fitness and competition ability with their parental strains.The sporulation,fitness and competition of DX 2-3 20m and DX 2-3 F7 were higher than the parental strains,contributing to the formation of resistance strains.It was suggested that P.capsici had a moderate resistance risk to mandipropamid.