The DNA of 242 Magnaporthe grisea isolates from Mile County, Yunnan Province, which originated from monoculture and mixture fields, was extracted and amplified by rep PCR which primers were from palindromes Pot2 of Magnaporthe grisea. All isolates were amplified 2-28 DNA bands, the size was from 400 bp to 23 kb, but mainly from 5-10 kb and 80% bands were in 0.4-6.0 kb. Genetic structure of Magnaporthe grisea in different culture pattern fields by clustering analysis showed that there was relations...