小麦秆锈菌不同小种间相对生存能力研究

STUDIES ON THE RELATIVE SURVIVAL ABILITY OF DIFFERENT RACES OF PUCCINIA GRAMINIS F. SP. TRITICI IN MIXTURES

将我国小麦秆锈菌优势小种21C3分别与历年来出现频率很低的34C1或116小种的夏孢子等量混合,在不同温度条件下,转接于八个来自次要越冬区长江中下游感病的生产品种上。经几个夏孢子世代的继代转接结果表明:21C3小种的毒力虽弱但与34C2或116种相比,其相对生存能力强;而34C2和116小种的毒力虽强,但相对生存能力却弱。小种间毒力强弱与其生存能力强弱呈负相关的现象,可能是我国小麦秆锈菌21C3小种在相当长的时期处于优势的原因之一。在一定高温条件下,虽能影响小种频率上升或下降的速度,但未能左右其总的趋势。试验应用的继代品种对不同小种的感病性没有显著差别。

Fresh urediospores of race 21C3 of wheat stem rust were equally mixed with those of race 34C2 or 116.The mixture was inoculated to the eight wheat cultivars which were selected from different winter-sowing areas. The reproduced rust sori from the mixture were reinoculated to the eight cultivars from generations to generation.It was found that the race 21C3 had higher survival ability than races 34C2 and 116.This result indicates that the survival ability of pathogen is negatively correlated to its virulence, which explains that the race 21C3 holds the trend to predominance.