Study On Sensitivity To Four Fungicides And Genetic Diversity Of Monilia Mumecola

Peach brown rot caused by Monilinia spp. is an important disease on peach worldwide. In China, the main species causing brown rot of peach are M.fructicola, M. yunnanensis, M. mumecola, respectively. In current study, peach brown rot samples were collected from different provinces and isolates were obtained and identified to species level by molecular method. Then the M. mumecola isolates were used to investigate the fungicide sensitivity and genetic diversity.(1) In the summer during 2013-2014, we obtained 195 isolates of brown rot fungi from different locations. Among them 51 were from Daye, Hubei Province,61 from Shangyu, Zhejiang Province,22 from Beijing,61 were from Chongqing. All the 195 isolates were identified by molecular method and 186 of them are M. fructicola,3 are M. mumecola,6 are M. yunnanensis.(2) In this study,93 isolates of M. mumecola obtained as described above in this study and previous studies were used to assay the sensitivity to four fungicides and analyze the genetic diversity. The results showed that the average EC50 values for carbendazim, tebuconazole, azoxystrobin, boscalid were 0.103 μg/ml,0.034μg/ml,0325ug/ml and 0.419μg/ml respectively. The sensitivity distribution of the tested isolates to the four fungicides showed continuous unimodal curves, close to the normal distributions, indicating that no resistance occurred in M. mumecola to these fungicides.(3) The genetic diversity of 93 isolates of M. mumecola from different hosts at four different locations were analyzed by SNP molecular markers. The results showed that most of the isolates from Xiangfan and Chongqing were gathered together, but separated from isolates from Wuhan and Ezhou that were clustered together, indicating that isolates from different locations had certain different genetic diversity. However, isolates from different hosts in the same locations clustered together completely, which indicated that isolates from different hosts did not show the apparent genetic diversity, suggesting that the M. mumecola isolates may infect different hosts in the same places.