西南地区稻瘟病菌对戊唑醇的敏感性基线建立及抗性监测

Sensitivity base-line and resistance detection of Magnaporthe grisea to tebuconazole in southwest of China

于2013-2014年分别从重庆市及四川、贵州省的16个区县采集分离获得902株稻瘟病菌，采用菌丝生长速率法测定了其中150个菌株对戊唑醇的敏感性。结果表明：其EC50值分布在0．0475～0．5996μg／mL之间，平均EC50值为（0．2154±0．1497）μg／mL。菌株的不同敏感性频率呈连续单峰曲线分布，因此其平均EC50值0．2154μg／mL可作为田间稻瘟病菌对戊唑醇敏感性检测的参考标准。戊唑醇对菌株的最低抑制浓度（MIC）值≤4μg／mL，以4μg／mL作为抗性菌株监测的区分剂量，测定了各地病原菌对戊唑醇的田间抗性，发现自各地采集分离的902株稻瘟病菌多数对戊唑醇仍表现为敏感，仅2株为低水平抗性。

Nine hundred and two isolates of Magnaporthe grisea were isolated from rice neck-panicles collected from 16 counties in Chongqing, Sichuan and Guizhou province in 2013 and 2014. In this study, the sensitivity of 150 isolates of M. grisea to tebuconazole was tested by the mycelium growth rate method. The results showed that the ECso values of M. grisea isolates to tebuconazole ranged from 0. 047 5 to 0. 599 6 μg/mL, which showed a skewed unimodal distribution, suggesting the average of ECso values （0. 215 4 μg/mL） could be used as the reference of M. grisea sensitivity base-line to tebuconazole in the southwest of China. The minimum inhibitory concentration of tebuconazole to M. grisea was ≤ 4 μg/mL. Using 4 μg/mL as discriminating dose to screen tebuconazole-resistant isolates, among all 902 isolates, only 2 lowed-resistant isolates were detected