黑龙江省核盘菌致病性分化研究

Study on Pathogenicity Differentiation of Sclerotinia sclerotiorum Isolated from Different Regions in Heilongjiang Province

为进一步明确核盘菌种群内致病力分化现象,采用离体叶片菌饼接种方法,以向日葵品种‘丰葵杂1号’为供试寄主,对采集自黑龙江省6个地区18个县的大豆和向日葵两种寄主植物的93个核盘菌菌株进行了致病性测定。结果表明,除14个菌株不能致病外,其余79个菌株均能引起向日葵叶片发病,但所致病斑直径的大小差异很大（0.2~5.3 cm）,中等致病力菌株数量较多,共占总菌株数的66.7%。来源于同一地区以及同一地块的菌株其致病性也达到了极显著差异,说明在所测定的核盘菌分离株内确实存在着致病力强弱明显不同的菌株,这种致病力强弱明显不同的现象与菌株来源地区和寄主来源间均无明显的关系。

In order to confirm pathogenicity differentiation within Sclerotinia sclerotiorum groups,ninety-threeisolates of Sclerotinia sclerotiorum isolated from soybean and sunflower in different regions of HeilongjiangProvince were tested for their pathogenicity to‘Fengkuiza NO1＇variety by the method of placing the myceliaplugs on the excised leaves.The results of inoculation on excised leaves of‘Fengkuiza NO1＇showed that,79 isolates had pathogenicity although the lesion sizes ranged from 0.2 cm to 5.3 cm in different isolates.However,no pathogenicity was found in fourteen isolates.The number of moderate pathogenicity isolates of Sclerotinia sclerotiorum were more than others and 66.7% proportion in the pathogen population.Furthermore,theextremely significant differences of pathogenicity were found among isolates even derived from the same regionand the same field.The results indicated that,the phenomenon of pathogenicity differentiation was existedamong isolates,which was no significant relationship to geographical location and host origin of the isolates.