Abstract:To reveal culture characteristics and genetic diversity of Ustilaginoidea virens isolates from 11 provinces in China, the hyphal growth rate, conidia number and conidia germination rate of 84 isolates were studied with biological methods, their genetic diversities were analyzed with RAPD-PCR assay. According to the hyphal growth rate, the isolates were divided into fast and slow types, which respectively accounted for 58.33% and 41.67%. Based on the sporulating abilities and conidia germination abilities, the isolates were divided into strong, moderate and weak types. RAPD-PCR analysis results show that, among total 323 bands amplified with 12 RAPD primers, polymorphic bands accounted for 98.14% with genetic distance between 0.02-1.00. On 0.725 genetic distance, 84 isolates could be classified into 7 genetic groups (R1 to R7), R4 and R5 were the predominant groups which include some subgroups. The isolates from different regions and from same region show different degrees of variations. The genetic variations of isolates were higher in inland regions than in oastal regions. The close genetic relationship was observed among isolates from rice varieties inoculated with same inoculum.