Abstract To know the genetic diversity and constitution of population of Ustilaginoidea virens in Fujian Province, the genetic diversity of 102 isolates on rice(Oryza sativa) collected from different rice growing areas in Fujian Province were assessed with RAPD(random amplified polymorphic DNA). A total of 157 bands were amplified by 10 primers selected from 100 random primers, with the percentage of polymorphic bands of 82.17% and genetic distance between 0.02~0.67. The results showed that there were significant genetic diversity in the population of Fujian, the highest genetic diversity of population was observed at rice growing areas of Mingxi(PPB=76.43， H=0.2212， I=0.3383)in comparison to the population of the other areas, and the genetic diversity of population from late season (PPB=91.08，H=0.2402， I=0.3655) were more diverse than that of early season (PPB=63.06, H=0.1892, I=0.2870). The result of cluster analysis revealed that 102 isolates tested could be classified into 7 genetic groups(R1 to R7) at 0.349 genetic distance level, and R1 was the predominant group contained 80 isolates in which existed some subgroups. And these groups had no obvious correlation with the geographic origin and the rice varieties origin of isolates. However, 10 isolates from Ninghua could be classified into 2 genetic groups, early season and late season, at 0.330 genetic distance level. The preliminary analysis show that geographic origin of isolates, rice varieties and their growing season may be the main factors for the genetic diversity of U. virens in Fujian, and play an important role in genetic variation of the pathogen, and occurrence and prevalence of the rice false smut.
