Identification of Tobacco Sclerotinia Rot in Yanbian and Screening for Resistant Germplasms

Identification of pathogen and screening for resistant germplasm materials were conducted for providing fundamental data and theory for controlling tobacco sclerotinia rot in Yanbian tobacco areas.The sclerotium of pathogen were collected in 2015, and then isolated and purified by conventional methods.Pathogen was identified through pathogenicity test, morphological characteristics, sequence analysis of the internal transcribed spacer region of the ribosomal DNA (rDNA-ITS) and phylogenetic analysis based on rDNA-ITS sequences.61germplasm materials were screened by in vitro leaf-assay method and living leaf-assay method.The results showed that:(1) The pathogen was identified asSclerotinia sclerotiorum(Lib.) de Baryby morphology and molecular biology methods.(2)31 high sensitive germplasms, 6 medium sensitive germplasms and 15 resistance ones were identified by the two methods with a consistent rate of 85.25%.No immune or high resistant germplasms, was identified.The pathogen of tobacco sclerotinia rot wasSclerotinia sclerotiorum(Lib.) de Baryin Yanbian tobacco areas.In vitro leaf-assay and living leaf-assay methods can be used to screen the resistance of germplasm materials to sclerotinia rot at seedling stages of tobacco.