摘要
为了解甘肃省裸仁美洲南瓜白粉菌对己唑醇敏感性及抗性产生情况，采用小株喷雾法对采自兰州、武威、景泰等地的20个南瓜白粉菌菌株对己唑醇的敏感性进行了测定，利用紫外诱导、药剂驯化、先紫外后药剂驯化三种方法对敏感菌株进行了抗药性诱导，并对抗性突变菌株的生物学性状及其对丙环唑、氟硅唑、腈菌唑和戊唑醇的交互抗性进行了研究。结果表明20个南瓜白粉菌菌株对己唑醇的敏感性存在一定差异，EC50值在17.77～285.54 μg/mL范围内；与其他两种诱导方法相比药剂驯化方法获得的抗性突变菌株的抗性倍数最高，为 8.94倍。敏感菌株和抗性突变菌株孢子萌发的最佳时间分别为36 h和48 h；抗性突变菌株产孢量和致病力明显高于敏感菌株；适合度测定表明抗性突变菌株与敏感菌株之间存在竞争力，孢子萌发率、芽管个数之间差异显著，菌丝分支数、产孢量之间差异不显著；抗性突变菌株在抗性突变菌株和敏感菌株混合比例为80∶20的群体中，存在頻率比较稳定，连续培养7代后仍占85.69%；己唑醇抗性突变菌株对丙环唑、氟硅唑、腈菌唑和戊唑醇4种药剂未表现出交互抗性。研究结果可为甘肃省防治南瓜白粉病提供理论依据。
关键词
裸仁美洲南瓜； 白粉菌； 己唑醇； 抗性诱导； 抗性菌株； 生物学性状； 交互抗性
中图分类号：
S 481.4
文献标识码： A
DOI： 10./j.zwbh.
Resistance induction of Podosphaera xanthii in pumpkin to hexaconazole and
biological characterization of its resistant strains in Gansu
LIANG Qiaolan， WEI Liexin， LIU Lilong， WU Qiong， XU Bingliang
. The optimum times for spore germination of sensitive strains and resistant mutant strains were 36 h and 48 h， respectively. The sporulation and pathogenicity of resistant strains were higher than those of sensitive strains， and there were significantly differences in conidial germination percentage and the number of germ tubes between resistant mutant strains and sensitive strains； however， the difference in their mycelial branch and sporulation rate were not significant. Resistant mutant strains were more stable in the mixed ratio of resistant and susceptible strains of 80：20， and still accounted for 85.69% after continuous cultivation for 7 generations. Resistant mutant strains to hexaconazole exhibited no crossresistance among the 4 kinds of triazole fungicides， i.e. propiconazole， myclobutanil， flusilazole， and tebuconazole. The results provided a theoretical basis for the efficient application of hexaconazole for the control of pumpkin powdery mildew in the field in Gansu Province.
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