摘 要 ：采用带菌牙签活体茎秆穿刺接种法和离体叶片菌饼接种法,以3个品种的油菜为供试寄主,对陕西省5个地区10个县的油菜和其它5种寄主共495个核盘菌分离株进行了致病性测定。结果显示,两种接种方法接种3个不同油菜品种所反映的不同分离株的致病趋势一致。离体叶片菌饼接种蓉油12号除来自勉县和城固县的2个分离株不能致病外,其余493个分离株均能致病,但各 分离株所致病斑直径差异很大, 为0.5~42.6 mm, 其中病斑直径在10~40 mm的分离株占94.7%,属于优势群体。同一地区甚至同一地块均存在不同致病力的分离株,不同寄主来源的分离株在油菜离体叶片上均能致病。说明核盘菌种内存在明显的致病性分化,这种分化与地理来源和寄主来源均无明显的相关性。
Abstract:Four hundred and ninety-five isolates of Sclerotinia sclerotiorum isolated from rapeseed and other five hosts in different regions of Shaanxi Province were tested for their pathogenicity to three rapeseed varieties using the inoculation methods of putting the toothpick with mycelia in the stems and placing the mycelial plugs on the excised leaves. It showed the similar results for both inoculation methods on three different rapeseed varieties. The results of inoculation on excised leaves of Rongyou12 showed that 493 isolates had pathogenicity although the lesion sizes ranged from 0.5mm to 42.6mm in different isolates. However, no pathogenicity was found in two isolates isolated from Mian County and Chenggu County. The 94.7% tested isolates showed their lesion sizes ranged from 10mm to 40mm, which were the majority in the pathogen population. Furthermore, the differences of pathogenicity were found among isolates even derived from the same region and the same field. The isolates from other hosts led to lesions on the rapeseed leaves as well. Our results indicated that the differentiation of pathogenicity among isolates was existed in Shaanxi, which was not affected by geographical location and host origin of the isolates.