以小麦条锈菌高感品种铭贤169为试验材料，设置了-50、-45、-40、-35、-30、-25、-20 ℃ 7个不同温度梯度，研究了小麦条锈菌夏孢子离体处理后的致病力。结果表明，在-35～-20 ℃低温下，条锈菌夏孢子可存活10 d，接种寄主小麦后病叶率2.36%～74.39%，平均严重度0.13%～4.21%；-40 ℃下可存活8 d，病叶率1.23%～2.78%，平均严重度0.01%～0.29%；-50 ℃下可存活6 d，病叶率1.04%～1.39%，平均严重度0.01%～0.17%。随着处理温度的降低，夏孢子致病力逐渐下降。在相同温度下，随着夏孢子离体处理时间的延长，致病力亦呈逐渐下降趋势。

In order to determine the pathogenicity of urediospore of Pst in vitro， the Mingxian 169 was used as the host， the incidence rate and disease severity of wheat leaves infected by Pst urediospore were studied after treatments with 7 different temperature gradients， -50 ℃、 -45 ℃、-40 ℃、 -35 ℃、 -30 ℃、 -25 ℃ and -20 ℃. The results show that the incidence rate was 2.36%～74.39%， severity was 0.13%～4.21% in -35~ -20 ℃ for 10 days； in -40 ℃ for 8 days， the incidence rate was 1.23%～2.78%， severity was 0.01%～0.29%, while no wheat infection for 9 days； in -50 ℃ for 6 days， the incidence rate was 1.04%～1.39%， severity was 0.01%～0.17%. The pathogenicity of summer spores gradually decreased. At the same temperature， the pathogenicity was gradually decreased with the elongation of summer spore separation.

S435.121.42

公益性行业(气象)科研专项(GYHY201406083)。