The Sensitivity Of Population Of Blumeria Graminis F. Sp. Tritici Isolates To Triadimefon And Azoxystrobin And The Mutation Detection Of Resistant Genes With Molecular Technology In China

The isolates of Blumeria graminis f. sp. tritici were sampled and isolated from 7 provinces / cities, and the sensitivity of 110 isolates to triadimefon and 130 isolates to azoxystrobin were both tested with seed treatment method and detached leaf segment methods, respectively. The results showed that the mean EC50 of the population to triadimefon was 118.24mg/L, and the mean resistance factor (RF) was 56.58. The frequency of resistant isolates to triadimefon reached to 99.09%. The high resistant isolates (RF>40) and the moderate resistant isolates (10<RF≤40) accounted for 49.09% and 47.27% respectively. All the isolates were resistant ones except only one sensitive isolates detected in Hubei Province. The base-line of B. graminis f. sp. tritici to azoxystrobin was 41.03mg/L. No significant cross-resistance was observed between triadimefon and azoxystrobin for B. graminis f. sp. tritici. These results will provide some references for the chemical control of the disease as well as the appropriate use of the fungicides.About the detection of the mutation sites of powdery mildew to the fungicides of triazole and strobilurins with the method of molecular biology, we have analyzed the sequence of cyt b gene of 81 isolates related to resistance, for the reason that the resistance of isolates to strobilurins have correlation with the mutation of cyt b, it has revealed that there is no mutation sites among these isolates. Because the resistance of isolates to triazole relates to CYP51 gene, we have also designed resistance specific premiers according to the mutation of the 398th site of the animo acides, and we have got the system of PCR molecular detection, and have tested 55 isolates using the resistant primers, it has shown that there is no target bands of the sensitive and low-resistant isolates, and the band producing frequency of the morderater & high resistant isolates are 8.33% and 41.38%, respectively. The research has laied basis for the molecular mechanism of the resistance of isolates to the sorts of triazole and strobilurins.