鄂西南地区2012-2014年稻瘟病菌致病性变化分析

为研究鄂西南地区稻瘟病病菌的致病型,将2012-2014年采自鄂西南地区感病水稻并分离保存的136个菌株分别接种到7个中国鉴别品种和15个水稻抗稻瘟病单基因系品种上,以中国鉴别品种中的丽江新团黑谷为感病对照,基于7个中国鉴别品种的鉴定结果表明:136个菌株中有121个具有致病性,分属于ZA、ZB、ZC、ZE、ZF、ZG共6群11个生理小种,ZB为优势种群,但ZC频率逐年升高,到2014年与ZB势均力敌;ZB13为第一优势生理小种,ZC15和ZB15所占比例逐年升高.15个水稻抗稻瘟病菌单基因系的鉴定结果将121个菌株分为77个致病型,且不同年份分离的菌株致病力差异较大.90%以上菌株对含有Pib、Pit和Pi11抗病基因的水稻单基因系有致病力,而对含有Pi9和Pikh抗病基因的水稻单基因系的致病力较弱,不到10%.此结果可以为育种工作者及当地农业部门的品种布局提供参考.

Pathogenicity changes of Magnaporthe oryzae in south-western Hubei Province during 2012-2014

To study the pathotypes of Magnaporthe oryzae in southwestern Hubei Province,seven Chinese identification rice cultivars and 15 near isogenic lines of rice with single blast resistant gene were inoculated with 136 strains isolated from rice infected during 2012 to 2014,using Lijiangxintuanheigu(LTH) as susceptible control.The results showed that 121 strains with pathogenicity to LTH were belonged to 13 physiological races in 6 groups including ZA,ZB,ZC,ZE,ZF,and ZG based on the pathogenicity to the seven Chinese identification rice cultivars.Among these groups,ZB was the dominant population,while ZC increased significantly over the years,reaching about the same frequency as ZB in 2014.ZB13 was the first dominant physiological races,while ZC15 and ZB15 increased significantly over the years.According to the phenotypes of the 15 near isogenic lines after inoculation,the 121 strains were divided into 77 pathogenic types,among which strains isolated from different years exhibited large difference in virulence.Over 90% of the strains tested were virulence tomonogenic rice lines with Pib,Pit,and Pi11,while less than 10% were virulence tomonogenic rice lines with Pi9 and Pikh.It will provide guidelines for local farmers,breeders,and agricultural sectors in choosing and developing rice varieties in this region.