【摘要】 稻瘟病是最主要的水稻病害之一,人工接种鉴定是稻瘟病抗性鉴定的主要手段。接种鉴定用稻瘟病菌在继代培养过程中时常发生变异,为了解其变异特点,本研究通过在CM完全培养基和燕麦培养基中连续对10个稻瘟病菌田间菌株继代培养10代,对其每代的产孢量、菌落形态、生理小种及对24个丽江新团黑谷(LTH)单基因系致病性变化进行研究。结果表明,随着继代代数增加,多数菌株在第5代产孢量、生理小种及致病性都发生了部分变异,10个菌株中有6个菌株在第5代生理小种已发生变异,特别是菌株P10由ZA种群转变为ZC种群;菌株P3、P5和P8的生理小种从始至终没有变化,但菌株P3和P5对部分单基因系的致病性已发生改变。因此,在选择菌株进行稻瘟病抗性鉴定时,菌株继代应少于5代,尽量用原始菌株。更多还原

【Abstract】 Rice blast is one of the most important rice diseases. Inoculation identification is a major means to identify rice blast resistance of rice varieties. The variation often occurs in the subculture of the Magnaporthe oryzae for inoculation identification. To understand the feature of its variation, ten strains of rice blast fungus collected from rice plants in Hunan were successively subcultured in both of the oatmeal medium and complete medium(CM) for 10 generations. The sporulation, colony morphology, physiological race and pathogenicity to 24 LTH single gene lines of every generations were studied. The results showed that with the increase of the subcultured generations, most of the ten isolations began to change in the fifth generation(G5) in the sporulation, physiological races and pathogenicity. Among ten isolations, six had the change of physiological race in G5, especially the isolation P10 was changed from ZA population to ZC population,but the isolations P3, P5 and P8 did not change the physiological race all through the generations from G0 to G10. However,P3 and P5 changed in the pathogenicity to some of the LTH single-gene lines. Therefore, the strains to be selected for rice blast resistance identification should be less than 5 generations, and the original strains should be used as far as possible.更多还原