广西稻瘟病菌生理分化及对4个水稻品种的毒性测定

Physiological differentiation of rice blast fungus and their toxicity to four rice cultivars

【目的】研究广西桂北、桂南、桂中、沿海及右江河谷等稻瘟病偏重发生的部分县(市)稻瘟病菌生理分化、无毒基因类型和出现频率,为水稻品种合理布局和稻瘟病持续控制提供理论依据。【方法】以7个中国稻瘟病鉴别品种和4个单基因水稻品种为试验材料,对从广西5个县(市)稻瘟病样本中分离获得的104个稻瘟病菌株进行生理分化和致病性测定。【结果】供试的104个稻瘟病单孢菌株分属于6个群(ZA、ZB、ZC、ZD、ZE、ZG),共24个生理小种,其中优势种群为ZB群,优势小种为ZB群1、9和15号小种。104个稻瘟病菌株在4个单基因水稻品种的毒性频率分别为89.42%、55.77%、82.69%和72.12%,相应的无毒基因频率分别为10.58%、44.23%、17.31%和27.88%。来自全州县、鹿寨县、合浦县、平果县和桂平市的104个稻瘟病菌株所含的无毒基因类型基本一致,都包含有对Pi-a、Pi-ta、Pi-b、Pi-k等4个抗性基因的无毒基因类型,各地出现的无毒基因频率有一定差异。【结论】广西田间稻瘟病菌群体结构复杂、生理小种数量大是水稻品种抗病性容易丧失的主要原因;来自广西不同地区的稻瘟病菌株间无毒基因出现频率有差异,含有抗病基因Pi-b的水稻品种比含有抗病基因Pi-ta、Pi-a和Pi-k的水稻品种对于稻瘟病有更强的抵抗能力,具有较高的应用价值。

[Objective]The aim of this experiment was to study physiological differentiation, avirulence gene types and occurrence frequency of different rice euhivars so as to provide relevant data for appropriate layout of rice cuhivars and continuing control of rice blast. [ Method ] Seven Chinese differentiation types of rice blast and four single-gene rice varieties were used to determine physiological differentiation and pathogenicity of 104 rice blast strains obtained from five counties （cities） in Guangxi. [Result]The 104 tested single-spore strains were categorized into six groups （ZA, ZB, ZC, ZD, ZE, ZG） and 24 physiological race types, among which dominant group was ZB and dominant physiological race types were 1, 9 and 15 from ZB. The toxicity frequency of 104 rice blast strains in four-single rice cuhivars was 89.42, 55.77, 82.69 and 72.12%, respectively, which avirulence gene frequency was 10.58, 44.23, 17.31 and 27.88%, accordingly. The rice blast strains from Quanzhou, Luzhai, Pingguo and Gulping basically had the same avimlence gene type to resistant gene including Pi-a, Pi-ta, Pi-b and Pi-k. Avirulenee gene frequency trivially varied among various locations. [Conclusion]Resistance of rice cultivars was generally deprived of complex groups and numerous physiological race types of rice blast in field. The avirulence gene frequency was slightly different among different rice blast strains in different areas of Guangxi. Rice varieties contained with Pi-b were more applicable because they were more resistant to rice blast than those with Pi-ta ,Pi-a and Pi-k.