核盘菌接种不同抗性油菜后致病力分化的研究

为了解核盘菌致病力分化与寄主油菜品种抗性的关系,采用茎秆牙签接种法将单一核盘菌菌株接种至46份抗性表现不同的油菜品种茎秆上,再从46个接种茎秆内收集形成的菌核进行纯化和培养,获得46株核盘菌菌株,进而采用两种方法(室内离体叶片接种法和离体茎秆接种法),分别测定这46株核盘菌菌株对甘蓝型油菜品种黔油16号的致病能力。结果表明:不同核盘菌菌株在黔油16号上所致的病斑长度明显不同;相同来源菌株经两种接种方法所致病斑在长度上反映出的致病趋势一致,基本表现为中感﹥高感﹥低感﹥抗性。即来自油菜品种为"抗"类型上的对应菌株其致病力最弱,而来自"中感"类型上的对应菌株其致病力最强。结果说明核盘菌致病力强弱分化与油菜品种的抗性有关系。

Pathogenicity differentiation of Sclerotinia sclerotiorum from the same strains derived from different rapeseed inoculums

To investigate differentiation of Sclerotinia sclerotiorum pathogenicity, one S. sclerotiorum isolate was inoculated into rapeseed stem from cultivars with different resistance to the pathogen. After inoculation, 46 sclotia/strains from 46 inoculated rapeseed cultivars were collected followed by the second inoculation onto cultivar Qianyou 16 using 2 in vitro methods (toothpick inoculation and leaf inoculation). The second inoculation results showed that lesion length from these 46 sclotia/strains had significant difference. Both methods showed the same trends that the order of the isolate pathogenicity was mid-susceptive, high-susceptive, low-susceptive and resistant, according to the corresponding host cultivars. In other words, the isolate from resistant cultivar inoculum had the weakest pathogenicity, while the corresponding isolates from mid-susceptive cultivar inoculum had the highest pathogenicity. It suggested that the differentiation of S. sclerotiorum pathogenicity might be related to hosts’ resistance of oilseed rape.