夏玉米丝黑穗病菌保存环境与致病力关系研究

为探索夏玉米丝黑穗病发病条件,对不同保存时间（1 a、2 a、3 a、4 a和5 a）和不同保存方式（库存、地表0 cm、地下10 cm土层、地下20 cm土层、地下30 cm土层和地下40 cm土层）下夏玉米丝黑穗病菌的萌发率和致病力进行了测定。结果表明：随着保存时间的延长和土层保存深度的增加,丝黑穗病菌冬孢子的萌发率均呈逐渐下降趋势。相同保存方式下,随着保存时间的延长,丝黑穗病菌的致病力逐渐下降;相同保存时间下,随着土层保存深度的增加,不同保存方式下的丝黑穗病菌致病力依次下降。相关分析表明,不同保存方式和不同保存时间均与病菌活力密切相关,符合二元线性回归方程;病菌致病力与病菌保存深度（负值）呈极显著正相关关系,与病菌保存时间呈极显著负相关关系。建议在夏玉米丝黑穗病发生区,采取清除田间病株、深翻以及2 a以上轮作等措施,以有效减轻玉米丝黑穗病害的发生。

Study on the Relationship Between Preservation Environment and Virulence of Sporisorium reilianum

In order to explore the occurrence conditions of summer maize head smut,the virulence and the rate of germination of Sporisorium reilianum in summer maize was investigated in different preservation times（1 a,2 a,3 a,4 a and 5 a） and ways（warehouse preservation,surface preservation,10 cm soil layer,20 cm soil layer,30 cm soil layer and 40 cm soil layer）.The results showed that the germination rate of winter spore of Sporisorium reilianum was gradually decreased with the extension of the storage time and the increasing of soil preservation depth.The virulence of Sporisorium reilianum was gradually reduced with the extension of the storage time under the same preservation ways,and the virulence was gradually reduced with the increasing of soil preservation depth under the same storage time.Correlation analysis showed that the preserved ways and preservation times were closely related to bacteria activity,and it conformed to the binary linear regression equation.The virulence had very signifieant positive correlation with the preservation depth and very significant negative correlation with the preservation times.Therefore,it suggested that the disease strain should be cleared in the field,deep tillage,over two years rotation and so on in summer maize head smut districtin,which could effectively reduce the occurrence of the disease.