将水稻白叶枯病噻枯唑抗性菌(Sa~r)和叶枯净抗性菌(P~r)的适应度(Fitness)特性进行了比较。当Sa~r和P~r与敏感菌(S)的等量混合物在植株上繁殖时,Sa~r和P~r竞争不过S,但P~r竞争能力较Sa~r强。Sa~r和P~r的致病力与S的无明显差异。但在离体保存时Sa~r和P~r易于丧失致病力。这种致病力的丧失是由于被保存的群体中低致病力的敏感菌比例上升所致,进一步说明Sa~r和P~r的适应度不及S。结果表明,白叶枯病菌抗药性菌适应度较差,在田间不易建立抗性群体,但不排除在高强度选择压力下也会出现抗性群体的可能。P~r在田间则比Sa~r易于建立抗性群体。 Fitness characteristics of rice bacterial blight resistant to thiophene (Sa ~ r) and leaf blight resistance (P ~ r) were compared. Sa ~ r and P ~ r did not compete with S, but P ~ r was more competitive than Sa ~ r when the equal mixture of Sa ~ r and P ~ r with susceptible bacteria (S) was propagated on the plants. The pathogenicity of Sa ~ r and P ~ r had no significant difference with that of S. However, Sa ~ r and P ~ r were easy to lose virulence in vitro. This loss of virulence is due to a rise in the proportion of susceptible strains with low virulence in the preserved population, further illustrating that S r and r P have less than adequate fitness. The results showed that the bacterial susceptibilities of bacterial blight were poor, and it was not easy to establish resistant populations in the field, but it could not be ruled out that the resistant populations would appear under the high selection pressure. P ~ r in the field than Sa ~ r easy to establish resistance groups.