2009年我国部分麦区小麦白粉病菌群体对温度的敏感性研究

 用小麦离体叶段法，设置22、23、24、25和26℃共5个温度处理，对2009年采自四川、北京、甘肃、河南、河北、陕西和湖北七省（市）的小麦白粉菌标样分离获得的129个单孢堆菌株对温度的敏感性进行了测定。结果表明，供试的129个菌株平均ET₅₀为22.49℃，其中ET₅₀最高为24.48℃，最低为19.88℃，供试菌株中40.52%的ET₅₀介于23℃和24℃之间，占参试菌株的近一半，7.63%的供试菌株ET₅₀≥24℃。不同省（市）的病菌群体对温度的敏感性存在一定差异，且病菌群体对温度的敏感性差异与经纬度存在显著或极显著的负相关关系。研究结果获得了温度对此病害的终止阈值平均为26.65℃，且对温度相对不敏感菌株在较高温度下的潜育期较短、病害的严重度较高。不同敏感性菌株的频率分布结果表明，自然环境中病菌群体已受到温度的选择压力。

The sensitivity of population of Blumeria graminis f.sp.tritici isolates to temperature in 2009

The sensitivity of 129 isolates of Blumeria graminis f．sp．tritici sampled from 7 provinces or cities such as Sichuan, Beijing, Gansu, Henan, Hebei, Shaanxi and Hubei  in 2009 was tested. The detached leaf segment method was used at 5 different temperatures which were 22℃, 23℃, 24℃, 25℃ and 26℃. The results showed that the mean ET₅₀of tested isolates was 22.49℃.The highest and the lowest ET₅₀of isolates were 24.48℃ and 19.88℃, respectively. ET₅₀ values of 40.52% isolates were between 23℃ and 24℃ represented nearly half of the isolates, and ET₅₀ values of 7.63% isolates were more than 24℃.There were a certain difference in sensitivity of pathogen populations to temperature among different provinces or cites, and significantly or highly significantly negative relationships between the sensitivity of pathogen populations and the longitude or latitude. The mean value of temperature threshold of 129 isolates tested was 26.65℃. The latent period of the isolates which were relatively not sensitive to temperature was shorter, and their disease severity was higher than that of sensitive isolates at higher temperature. The results of frequency distribution of the isolates with different sensitivity to temperatures revealed that the pathogen population in natural environment had been effected by the selection pressure of temperature.