中国南瓜自交系112-2对白粉病的抗性鉴定

Verification of Powdery Mildew Resistance to a Cucurbita moschata Inbred Line '112-2'

试验以"蜜本"南瓜为对照,以Sphaerotheca fuliginea(Schlecht.ex Fr.)Poll.白粉病为病原菌,采用幼苗期接种鉴定、成株期叶片叶盘法接种鉴定和田间调查的方法鉴定中国南瓜"112-2"自交系对白粉病的抗性,并在扫描电镜下比较了它们的叶片表面结构。结果表明:苗期接种白粉病11 d后,"112-2"自交系的病情指数显著低于"蜜本"南瓜,病情指数分别是28.8和47.6;叶盘法接种4 d后,"112-2"自交系的病情指数显著低于"蜜本"南瓜,病情指数分别是7.5和38.6;田间调查"112-2"自交系和"蜜本"南瓜的病情指数分别为0和21.7;说明"112-2"自交系是高抗白粉病的材料。在电镜下观察,"112-2"自交系的气孔密度、刚毛密度和刚毛长度显著大于"蜜本"南瓜,而气孔长度和宽度显著小于"蜜本"南瓜。

‘Inbred 112-2＇,a selected 8-self-generation inbred line,was discovered showing higher resistance to the powdery mildew fungus by many years field observation.To verify the resistance of‘Inbred 112-2＇ to the powdery mildew fungus,‘Miben＇,a widely cultivated pumpkin cultivar in China was used to be control.Sphaerotheca fuliginea, a main powdery mildew fungus occurred in C.moschata,was inoculated into leaves of 1-leaf seedling and leaf discs of adult plant respectively.The disease index of adult leaves infected naturally in field,inoculated seedling leaves and inoculated leaf discs were investigated respectively.In addition,scanning electron microscopic（SEM ） observation to the normal leaves surface morphology of two tested materials were also performed.The results showed that the disease index of‘Inbred 112-2＇ were significantly lower than that of‘Miben＇ using field natural infection,artificial inoculation of seedling and adult plant leaf discs.Their corresponding disease index values of‘Inbred 112-2＇ by three different methods were 0,28.8 and 7.5 respectively,while those of‘Mben＇ were 21.7,47.6 and 38.6.So we draw a conclusion that‘Inbred 112-2＇ was a higher resistance inbred to powdery mildew.SEM observation showed that leaves surface morphology of‘Inbred 112-2＇ had higher stomata density,trichome density and smaller stomata size than those of‘Miben＇,but it should be further studied that whether there was inevitable correlation between higher resistance of‘Inbred 112-2＇ than‘Miben＇ and difference of their leaf surface morphology.