北京地区番茄晚疫病新菌株致病性鉴定及部分主栽品种与品系的抗性评价

番茄晚疫病是危害番茄生产的重要病害之一。在我国开展番茄晚疫病菌致病性分化研究对番茄抗病品种选育和番茄晚疫病的综合防治意义重大。以往的研究结果表明，番茄晚疫病菌具有明显的生理小种分化现象，且致病性分化变异频繁。2001年，从北京地区采集并获得了一份番茄晚疫病新菌株，以番茄晚疫病菌的5个鉴别寄主品种为材料，采用苗期喷雾接种法对其致病性进行了研究。根据致病性表现初步得出结论，该菌株属于晚疫病生理小种T1.3。同时，利用该菌株对7份番茄一代杂种和10份育种材料接种鉴定表明，7份一代杂种品种均高度感病；而10份番茄育种材料中，7份表现感病或高感病，3份耐病。另外，在2份耐病品系和3份感病材料中均存在一定比例的抗病单株；而两个感病亲本杂交后，其F1抗性明显增强。可见，番茄晚疫病抗性并非简单的由单显性基因控制的遗传模式。

Pathogenicity of a New Isolate of Phytophthora infestans from Beijing and Resistance Evaluation of Tomato Materials

In 2001,a new pathogen strain of tomato late blight caused by Phytophthora infestans(Mont.) was isolated from Beijing,and its virulence was analyzed based on the reaction to five differential hosts by spray inoculating at seedling stage.A preliminary conclusion was drawn that the new pathogen strain was physiological race T1.3 of Phytophthora infestans.In addition,7 varieties of F_(1) hybrid and 10 breeding materials were inoculated with this pathogen strain.All of the 7 varieties were susceptible.Out of 10 tested breeding materials,7 accessions were susceptible,and the rest 3 accessions were tolerance.Moreover,resistant individuals were found in two tolerant lines and three susceptible materials,and the hybrid of two susceptible lines was more tolerant than their parents.The result showed that the resistance of tomato to late blight was not absolutely relied on single dominant gene.