【摘要】 1996年对北方粳稻区稻瘟病菌生理小种鉴定和毒性频率分析的结果表明 ,小种 337、 2 37、0 0 3、 137和 537为该稻区的优势小种 ,不同地区优势小种的分布及病原菌群体的遗传多样性存在明显差别。对病原菌群体进行毒力频率分析的结果发现 ,该稻区的稻瘟病菌对已知抗性基因 Pi- z、 Pi- zt、Pi- t和未知抗性基因近等基因系 F- 2 1- 6、F- 2 5- 3、F- 4 0 - 3、F- 59- 1和 F- 66- 10的毒力频率较低 ,在 2 %～ 10 %之间 ,这说明上述抗性基因和未知抗性基因抗源在水稻育种上具有较高的利用价值。同时 ,本研究比较和分析了北京、天津和丹东地区在 3个不同时期 ( 1985～ 1987年、 1990～ 1992年和 1996年 )的稻瘟病菌群体的变化情况 ,结果发现随着栽培品种的更替和时间变迁 ,各地稻瘟病菌群体结构都表现出日趋简单的趋势 ,主要小种的组成及群体毒力频率均发生了根本性变化。另外 ,本文还就栽培品种对病原菌小种分布的影响、抗病品种种植面积与毒力小种群频率的关系等问题进行了讨论更多还原

【Abstract】 The study of pathologic races of blast fungus Pyricularia grisea showed that rac es 337, 237, 003, 137 and 537 were dominant races in japonica rice growing regio n of Northern China. Both the distribution of these dominant races and the genet ic diversity of pathogen populations in different rice growing districts were o bviously different. The virulence frequency analysis indicated that the virulenc e frequency of blast pathogen to three known resistance genes Pi z, Pi z t , Pi t and five near isogenic lines (NILs) F 21 6, F 25 3, F 40 3, F 59 1, F 66 10 was very low, from 2% to 10%. This meant that these resist ance genes and NILs had high utilization value in rice breeding. At the meantime , blast pathogen population structures were compared and analyzed during three p eriods (1985~1987, 1990~1992 and 1996) in three districts (Beijing, Tianjin and Dandong). The results demonstrated that with the alternation of cultivars and t he shift of time, the blast population structures in these three districts were getting simpler and simpler, and main race constitutes and virulence frequency o f pathogen population also exhibited great changes. In addition, some problems s uch as the effect of cultivars on distribution of blast races, and the relations hip between growing area of resistant cultivars and frequency of virulent race p opulation were further discussed in this paper.更多还原