Abstract: Genetics of kitazin P resistance in asexual recombination of Magnaporthe griseawas studied by using nitrate non-utilizing (nit) mutants. Asexual recombinants were detected in all the three pairings, namely DY2-3(nit1-LR)×A7-3(nitM-S),A7-3(nitM-S)×F4-2(nit1-MR), and F4-2(nit1-MR)×DY2-4(nitA-LR). The frequencies of the asexual recombinations were 7.31%, 14.00% and 8.63%, respectively. Most of recombinants had satisfied growth, spore production and pathogenicity ability, indicating that asexual recombinants had high fitness. These results suggested that asexual recombination caused by hyphal fusion might play an important role in the development of fungicide resistant population in M. grisea.

Key words: Magnaporthe grisea, kitazin P resistance, asexual recombination, nitrate non-utilizing mutants, fitness

摘要： 采用硝酸盐利用缺陷突变体（Nitrate nonutilizing mutants， nit）为遗传标记研究了稻瘟病菌对异稻瘟净的抗药性在无性重组过程中的遗传学。在DY23（nit1LR）×A73（nitMS）、A73（nitMS）×F42（nit1MR）和F42（nit1MR）×DY24（nitALR）3个配对组合中都检测到了无性重组体，重组频率分别为7.31%、14.00%和8.63%。大多数无性重组体都有较好的生长、产分生孢子能力和致病力，表明无性重组体有较高的适合度。这些结果说明由菌丝融合导致的无性重组在稻瘟病菌对异稻瘟净的抗药性群体发展中可能起着重要的作用。

关键词: 稻瘟病菌, 异稻瘟净抗药性, 无性重组, 硝酸盐利用缺陷突变体, 适合度