小麦白粉病菌生理小种的鉴定与病菌毒性的监测

１９９１～１９９４年小麦白粉病菌生理小种鉴定的结果表明，１１，１５号小种这几年的优势小种，３１５号小种有上升的趋势，用毒性频率分析的方法对所获数据进行分析表明，Ｖ１，Ｖ３，Ｖ５及Ｖ８等毒性的当前白粉菌群体中已基本固定（毒性频率接近１００％），小麦白粉菌对Ｐｍ４ａ的毒性频率呈较快的上升趋势，说明Ｐｍ４ａ基因的使用应该审慎，白粉菌对Ｐｍ２１为目前最有效的抗白粉病基因，对北京，西南及江浙三地区小区白粉菌

MONITORING OF THE VIRULENCE POPULATION OF ERYSIPHE GRAMINIS F. SP. TRITICI

The physiological races of wheat powdery mildew (Erysiphe graminis f. sp. tritici) was surveyed on a set of nine differentials and on 20 cultivars with known resistance genes in 1991 - 1994. The results showed that Races 11 and 15 were the prevailing races. Race 315 showed the trend of increasing. The virulence frequencies of the corresponding resistance genes were also analysed. The results indicate that V1, V3, V5 and V8 were close to fixation. The frequency of wheat mildew to Pm4a gene presented more rapid rising. The virulence to Pm21 was still naught showing the most effective resistance so far. The virulence structures of the mildew populations from Beijing, the Southwest, and Jiangsu-Zhejiang regions were studied. V2, V4a, V4b and V2 VMld populations presented lower frequency in Beijing and Jiangsu-Zhejiang regions while it was over 30% in the Southwest region. The frequencies of V2 6 and V2 'Talent' were still low in all three regions. These indicate the effectiveness of the corresponding resistance genes in different regions. The comparison of the race survey and virulence analysis shows that virulence analysis can provide a simpler measure to understanding the virulence structure, the distribution and the dynamics of wheat powdery mildew populations. The result can also reflect the effectiveness of resistance genes in the region under survey.