掘氏疫霉有性生殖后代交配型和致病力遗传研究

ON INHERITANCE OF MATING TYPE AND PATHOGENICITY OF PHYTOPHTHORA DRECHSLERI IN SEXUAL PROGENIES

规定了掘氏疫霉有性后代单卵孢株的交配型及其遗传稳定性和致病力分化．结果表明，Ａ２和Ａ１Ａ２；型在遗传上不稳定，在单卵孢株保藏过程中可以发生变异，部分Ａ２菌株改变为Ａ１Ａ２型，而Ａ１Ａ２菌株改变为Ａ２交配型，但有部分Ａ１Ａ２菌株可以稳定保持其自孕能力．掘氏疫霉有性生殖后代发生明显的致病力分化现象，来自同一亲本的单卵孢后代对黄瓜、瓠子、笋瓜的致病力有明显差异，说明有性生殖对掘氏疫霉致病力变异可能起主要作用．

Inheritance and stability of mating types of single-oospore cultures of Phyloghlhora drechsleri from F1 and S1 progenies and differentiation of pathogenicity of Phytophthora drechsleri in sexual progenies were studied. Results showed that type A2 or A1A2 varied during Storage, some A2 single-oospore cultures convefted to A1A2, and some A1A2 convefted to A2, but some A1A2 cultures were still A1A2 after two and a half years storage, The results of single-oospore cultures pathogenic to cucumber, hispid bottle, and winter squash showed that an obvious differentiation of pathogenicity presented in sexual progenies of P.dreachsleri. It suggested that sexual reproduction might play an important part in the variation of pathogenicity of P. drechsleri.