玉米大斑病菌Ht－毒素在玉米品种抗病性鉴定中的应用

The Usage of Ht-Toxins in Identifying Resistance of Corn Varieties to Helminthosporium turcicum

玉米大斑病菌在活体外产生的致病毒素（Ｈｔ－毒素）不仅能抑制玉米幼苗根和芽的生长，而且对玉米离体根冠细胞也有明显的致死作用。试验发现，玉米大斑菌菌株的致病力与其培养滤液对玉米幼苗根生长的抑制率呈正相关（ｒ＝０．８４），玉米品种的感病性也与毒素处理后根冠细胞的死亡率呈正相关（ｒ＝０．８２）。结论指出，用玉米大班菌Ｈｉ－毒素鉴定玉米品种的抗病性是可行的。

The Ht-Toxins produced by Helminthosporium turcicum in vitro could significantly inhibit the growth of roots and buds and kill isolated root cap cells of corn. The exprimental results showed that the virulence of H. turcicum had significant possitive correlation with the toxicity of its cultural filtrate, and so did the susceptibility of corn varieties with the death rate of root cap cells treated by Ht-toxins. It was conclusion that it was possible to evalate the resistance of corn varieties to H. turcicum by using Ht-toxins.