大豆疫霉根腐病菌单游动孢子的毒性遗传与变异

 采用离体叶柄伤口接种法测定大豆疫霉根腐病菌44号生理小种单游动孢子连续3代或4代分离后代的毒性,结果表明:从S1中选择与亲本相比毒性不发生变异的1号单游动孢子菌株(44号生理小种)和变异最大的30号单游动孢子菌株(1号生理小种)继续分离2代或3代,单游动孢子毒性变异趋势主要是从44号生理小种变异为3号生理小种,也有变异成毒性公式为7或1a,7的单游动孢子。大豆疫霉根腐病菌无性世代毒性变异几率很高,多数单游动孢子毒性在分离后代中都发生变异,产生不同的小种或毒性公式,并且毒性变异基本不能稳定遗传。

Inheritance and variation in virulence of single-zoospore of Phytophthora sojae

Virulence of single zoospore, which was segregated progeny isolates of successive three or four generations of P. sojae race 44 single zoospore isolate, was evaluated after wounded excised inoculation of soybean seedling petiole. No 1 single zoospore isolate (race 44), in which virulence showed no variation compared with the original strain, was screened to reproduce two or three generations successively, and No.30 single zoospore isolate (race 1), in which virulence variation was the biggest compared with the original strain, was also screened to reproduce two or three generations successively for inheritance and variation in virulence analysis. The result demonstrated that variation tendency of single zoospore was mainly from race 44 to race 3 as well as virulence formula 7 or 1a,7. Variation of virulence in P. sojae asexual reproduction was present frequently, and most of single zoospore isolates in every generation produced different races or virulence formula. Essentially, variation in virulence of single zoospore segregated progeny isolates of successive three or four generations of P.sojae can not be inherited steadily.