小麦白粉病菌越夏,越冬和春季菌源毒性结构比较

 分析了1992年和1993年不同时期采集的小麦白粉病菌越夏、越冬和春季菌源共238个菌株的生理小种、毒性基因结构和对9个推广品种的毒力频率。结果表明三种菌源在生理小种和毒性基因组成及出现频率是相似的,对9个推广品种的毒力频率均较高。这样在白粉病菌毒性和品种抗病性研究中,可以采集应用越夏和越冬菌株标样,避免了夏季高温季节保存菌株的工作;而且从毒性结构方面进一步证实白粉病菌主要以分生孢子在夏季侵染高海拔地区的自生麦苗而越夏,再逐渐扩展至秋播麦苗越冬后导致春季大田发病,病菌的子囊孢子在平原地区侵染循环上作用不大。

A COMPARATIVE STUDY OF THE VIRULENCE CONSTITUTIONIN OVERSUMMERING, OVERWINTERING AND SPRING SOURCE OF ERYSIPHE GRAMINIS F. SP. TRITICI

A total of 238 isolates of Erysiphe graminis f. sp. tritici, collected from summer, winter and spring in 1992 and 1993, were analysed in the greenhouse for the constitution of race groups and virulence genes and virulence frequencies to commercial cultivars. The results showed that the constitution and frequencies of the race groups and virulence genes in the three sources in E. graminis f. sp. tritici. were similar, and the virulence frequencies to nine commercial cultivars were high. It is suggested that successive cycles of infection in E. graminis to wheat may mainly occur on plant surfaces during a year from the conidia, while the cleistothecia containing ascospores did not play an main role in the infection cycles.