Abstract:

Thirty one isolates of Colletotrichumspp. from different woody plants in Shaanxi province were collected and identified by morphological characteristics. Genetic diversity and phylogeny among the 31 isolates were investigated by sequence analysis based on the rDNA-ITS sequence variation, and compared with 11 relevent sequences from GenBank. The results showed that there was rich genetic diversity in Colletotrichum species; and the sequences diversity index was 01957. All the Colletotrichum isolates were clustered into three groups at the bootstrap value of 94%. The Colletotrichum gloeosporioides isolates were clustered into the G1、G2 and G3, respectively. Some isolates of this species exhibited extensive genetic variability compared with the other specie isolates. There was also genetic difference among the isolates collected from the same host tree. It is reasonable to use complex species (Colletotrichum gloeosporioides) to refer to the woody Colletotrichum pathogens at present.

Key words: Colletotrichum, rDNA-ITS, genetic diversity, phylogeny