玉米对纹枯病抗性的初步研究

Primary study on maize varieties resistance to sheath blight

通过田间人工接种对鄂西山地玉米区７个玉米品种进行抗纹枯病观察，结果表明：７个品种病指均在４５％以上，无高抗品种，但品种间存在着抗性差异，抗性与穗位节高度有密切关系。穗位节高（Ｘ）与病情指数（ｙ１）的相关系数，ｒ＝０．９６６，回归方程式为ｙ１＝１２６．０４—Ｏ．６６Ｘ。病株的穗位节高（Ｘ）与千粒重降低的克数（ｙ２）的相关系数ｒ＝０．８２１，回归方程式为ｙ２＝０．６３Ｘ—７７．７６。穗位节高度是选育抗纹枯病品种的一个重要指标。

The resistance of seven maize varieties to sheath blight was observed by usingartificial inoculation in the field.Experiments have shown:they are susceptible to sheathblight,their disease index is over 45%,but there are differences among varieties in resis-tance.The resistance is closely related to the height of ear segment.The coefficient of corre-lation between disease index(y1)and the height of ear segment(x)is 0.966**and their rela-tionship is y1=126.04-0.66x.The cofficient of correlation between the height of ear seg-ment(x)and tho reduction of a thousand-grain weight(y2)is 0.821*,their relationship is bythe following expression,y2=0.63x-77.76.So to select a fine variety highly-resistant tosheath bight is very important.Therefore a great attention should be paid to controllingmaize sheath blight when lowear segment varieties are recommended in the areas where maizesheath blight are disastrous.