八个玉米自交系对小斑病(O小种)田间成株期水平抗性因素的观察研究

 根据田间抗病性鉴定结果,选取高抗系齐31和凤白29(新),抗病系威风322和黄早4,中抗系获白,中感系黄204,感病系替423和罗31等八个玉米自交系,对玉米小斑病(Helminthosporium maydis)(O小种)田间成株期水平抗性因素的观察研究。在自然发病条件下,无论在病斑的面积,单位病斑面积上的产孢量或发病始期的病斑数量来看,八个自交系间都存在显著差异(P=0.01)。可是每个因素与田间抗病程度之间看不出有什么相关性。如果把三个因素乘积进行相关性测定,成株期抗病性与水平抗性三个因素乘积之间呈现高度相关性(r=0.85,P=0.01)。

PRELIMINARY STUDY ON THE FACTORS OF HORIZONTAL RESISTANCE OF EIGHT INBRED LINES OF CORN TO HELMINTHOSPORIUM MAYDIS

Eight inbred lines of field corn (Zea mays) differed in reaction to Helminthosporium maydis race O in the field plot tests. The factors cor-related with gross reaction to this fungal race were mainly in number and size of lesions, and quantity of sporulation on each lesion. None of these factors, however, was correlated with the degree of resistance to this fungus by these lines in the field. But a combined effect of these three factors (i.e. number and size of lesions and quantitiy of sporulation) showed significant correlation with the degree of susceptibility of the lines.
The results lead to the speculation that the resistance of field corn inbreds in China to Helminthosporium maydis is most likely horizontal in nature.