Monitoring Of Sensitivity Of Blumeria Graminis F.sp.Tritici Isolates To Fungicides And The RAPD Makers Of The Isolates With Different Fungicide Sensitivity

The fungicide resistance of wheat powdery mildew (Blumeria graminis f. sp. tritici) to triadimefon was monitored and the isolates, which were collected from Beijing, Shandong, Shanxi, Hebei, Henan, Hubei, Sichuan, Jiangsu and Xinjiang in 2001 and 2002, were tested. The results showed that the mean resistance factor (Rf) was 16.08 and 30.48 in 2001 and 2002, respectively. 33.66% and 36.70%, respectively in 2001 and 2002, of tested isolates showed the average resistance factor often to forty folds more than that of the sensitive ones. The highest resistance factor detected was 258.46 in 2001, and it was 142.97 in 2002. The frequency of isolates of resistance facotor over 40 was 3.96% and 27.52 % in 2001 and 2002/espectively.The result indicated that the resistance of the wheat powdery mildew to triadimefon is still a problem that cannot be ignored. The results of our study provided a reference for management of the resistance of wheat powdery mildew, as well as the development and the use of fungicides.The sensitivity of wheat powdery mildew to two strobilurin fungicides, SYP-Z071 and BAS490F, was monitored and the isolates, which were collected from Beijing, Shandong, Shanxi, Hebei, Henan, Hubei, Sichuan, Jiangsu and Xinjiang in 2001 and 2002, respectively, were tested. The results showed that the average ECso of the base-line sensitivity of wheat powdery mildew to SYP-Z071 is 57.89g /ml and that of BAS490F is 85.82g/ml when using seed dressing and detached leaf segment method.. By using the correlation analysis, we drew the conclusion that there was no cross-resistance in Blumeria graminis f.sp. tritici between triadimefon and SYP-Z071, or between triadimefon and BAS490F, which indicated that the combinations of fungicides of DMIs and strobilurins could be an effective measure to control the disease and an effective anti-resistance strategy to both of these two kinds of fungicides. The results of our study will provide a reference for the development and the use of fungicides studied, as well as the establishment of anti-resistance strategy to these fungicides.Random primers were used to amplify some isolates with different fungicide resistance by RAPD analysis of the genome DNA. The results revealed that there was considerable genetic diversity among wheat powdery mildew isolates. A band between 200bp and 300bp was foundto be associated with the tnadifmefon in two middle resistant and two high resistant isolates with primer OPE18. A band between 300bp and 400bp long was amplified from sensitive isolates to triadimefon with primer OPF4. A band about 700bp long was also obtained from two middle resistant and two sensitive isolates to strobilurins with primer OPF4. A band about 1400bp long was obtained from two sensitive isolates to strobilurins with primer OPE8.These markers associated with fungicide resistance/sensitivity laid the foundation for the genetics, the mapping, the cloning and the exploration of functions of the fungicide resistance genes.Postgraduate: Xia YeSpeciality: Plant PathologySupervisor: Associate Prof. Liu Xuemin...