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期 刊 ：植物保护学报 2011年

关键词：辣椒疫霉；甲霜灵；抗甲霜灵菌株；生物学性状；抗药性风险评估；

Keywords:Phytophthora capsici, metalaxyl, metalaxyl-resistant isolates, biological characters, resistance risk assessment,

摘 要 ：为了明确抗甲霜灵辣椒疫霉菌株的适生性,以田间自然产生及室内诱变获得的抗甲霜灵辣椒疫霉菌株为材料,测定了抗甲霜灵辣椒疫霉菌株的主要生物学性状。各菌株的游动孢子囊产生量为9.6×10³~13.0×10³个/mL,孢子囊释放率为61.3%~68.4%,游动孢子萌发率为35.3%~42.1%,适温条件下的菌丝平均生长速率约为10.28~11.55 mm/天;各菌株在含100 μg/mL孔雀石绿的CA培养基上均不能生长,淀粉水解指数为0.18~0.95;接种辣椒、番茄、南瓜、西葫芦和茄子等果实所致病斑平均直径分别为34.11、18.47、30.19、37.78 和32.73 mm。经方差分析,抗甲霜灵辣椒疫霉菌株的生物学性状与敏感菌株无显著差异,表明甲霜灵并未改变其生物学性状,辣椒疫霉对甲霜灵具有较高的抗性风险。

Abstract:In order to explore the fitness of metalaxyl-resistant (R) isolates of Phytophthora capsici, the main biological characters of the field metalaxyl-resistant isolates and laboratory-induced metalaxyl-resistant isolates of P.capsici were studied with the wild-type metalaxyl-sensitive (S) isolates as control. The results showed that the zoosporangium production by all isolates was 9.6×10³-13.0×10³/mL, the zoosporangium releasing ratio was 61.3% -68.4%, the germination ratio of the zoosporangia was 35.3% -42.1%, the average mycelial growth rate was 10.28-11.55mm/d, and the hydrolysis indices were 0.18-0.95. Both metalaxyl-sensitive and metalaxyl-resistant isolates didn‘t grow on CA with 100μg/mL malachite green, however, all the isolates infected the fruits of pepper, tomato, pumpkin, summer squash and eggplant, and the average diameter of lesions were 34.11, 18.47, 30.19, 37.78 and 32.73mm, respectively. The main biological characters had no significant differences between the metalaxyl-resistant and metalaxyl-sensitive isolates. This suggested that metalaxyl resistance mutation did not alter the main biological characters of P.capsici, and there might be at high risk of resistance to metalaxyl in P.capsici.

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