| Gray mold is a worldwide disease on tomato, infected by Botrytis cinerea Pers. Gray mold on tomato has appeared in our country since 1980s. It has become the restrictive obstacle in the production of tomato. At present, chemical synthesized fungicides are main to control of the gray mold. Commonly used chemical fungicide:benzimidazoles、 dicarboximides、pyrimidines, etc. However, the resistance problem had been more and more serious with the widely use of fungicide. At present, we did not find the resistance strain to Botrytis cinerea in tomato from Liaoning province to fludioxonil. Sensitivity determination and resistance risk assessment of the new fungicide fludioxonil is based on the theory of resistance management, it is important guiding significance to prevent or delay the occurrence of fludioxonil-resistant of Botrytis cinerea in Liaoning province. The study on the detection of sensitivity of Botrytis cinerea to different fungicides, comparative analysis sensitivity between different regions of Botrytis cinerea in Liaoning province to commonly used fungicides and new fungicide fludioxonil, study on fludioxonil with other fungicides cross-resistance, the biological character of fludioxonil-resistant mutants. The main results are listed as follows:The sensitivity of B.cinerea to fludioxonil、procymidone、carbendazim and pyrimethanil were tested by measuring mycelial from Liaoning province. The EC50 values ranged from 0.0007 to 0.0244μg/mL to fludioxonil, and the average of EC50 value was 0.0073μg/mL, the maximum value and the minimum value is 34.86 times. The EC50 value ranged from 0.0900 to 11.4996μg/mL to procymidone, and the average of EC50 value was 1.5275μg/mL, the maximum value and the minimum value is 127.7733 times. The EC50 value ranged from 0.1542 to 73.1932μg/mL to pyrimethanil, and the average of EC50 value was 3.6395μg/mL, the maximum value and the minimum value is 474.6641 times. The EC50 value ranged from 3.3490 to 1062.7638μg/mL to carbendazim, and the average of EC50 value was 169.8858μg/mL, the maximum value and the minimum value is 317.3377 times. In addition to all of sensitive strains of B.cinerea to fludioxonil, it has the appearance of resistant strains of B.cinerea to other fungicides, and B.cinerea on fludioxonil, procymidone, carbendazim, pyrimethanil resistance frequency was 0,35.04%,100%,96.58%.SPSS software was used to analyze the variance of single factor variance of EC50 in different regions. Multiple Tukey’s comparative test analysis of variance, P=0.384>0.05, different regions of the B.cinerea in tomato on the EC50 difference is not significant. Measured date by using SPSS software to K-S method of nonparametric test, P= 0.089> 0.05, tested 117 strains of B.cinerea in tomato to fludioxonil sensitivity frequency conforms to normal distribution. The baseline sensitivity (0.0073±0.0045)μg/mL of B.cinerea in tomato was established in each region. Among the 117 strains of B.cinerea EC50 was the highest in the 0.0030～0.0060 of the strains, which was 29.91%, and the other frequencies were decreased in turn. Apart from Liaozhong county in Liaoning province, there was no significant difference in EC50 values of B.cinerea strain to procymidone between regions, there are some differences in sensitivity of B.cinerea strain to procymidone between Liaozhong county and other regions. The maximum mean EC50 value of B.cinerea strains to procymidone in Liaozhong area, the minimum mean EC50 values of B.cinerea isolates to procymidone in Pulandian, and EC50 value of other parts of B.cinerea isolates to procymidone were distributed between the two regions. There are some differences in sensitivity of B.cinerea to pyrimethanil in various regions of Liaoning province, EC50 value and mean EC50 value of B.cinerea strains to pyrimethanil range is the minimum in Haicheng area, the maximum mean EC50 value of B.cinerea to pyrimethanil in Beipiao area, the EC50 value of B.cinerea strains in other area were distributed between Haicheng city and Beipiao city. There are some difference in the sensitivity of B.cinerea strains to carbendazim between Haicheng city and other regions, the maximum mean EC50 value of B.cinerea to carbendazim in Haicheng city, the minimum mean EC50 value of B.cinerea to carbendazim in Pulandian city, the minimum EC50 value of the tested strains to carbendazim is the city of Shenyang, the maximum EC50 value is in Beipiao city, the highest EC50 values can be achieved 1062.7638μg/mL.Fludioxonil on different strains of EC50 of numerical and procymidone, carbendazim, pyrimethanil strains corresponding to the correlation coefficient between the numerical respectively 0.106 (P=0.658)、-0.183(P=0.439)、0.364 (P= 0.115), P= 0.05 did not reach level of significance, there is no cross-resistance between fludioxonil and procymidone、 carbendazim or pyrimethanil.7 fludioxonil-resistant mutants were induced by UV irradiation and fungicide adaption.4 fludioxonil-resistant mutants were induced by UV irradiation and 3 fludioxonil-resistant mutants were induced by fungicide adaption. There was significant difference in resistant mutants and their parental isolates of mycelial growth rate, sclerotia capacity, pathogenicity. The results that the mycelial growth rate, sclerotia production and pathogenicity of resistant mutants decreased as compared with their parental isolates, the sporulation capacity and sporulation time of resistant mutants were similar with their parental isolates; the resistance obtained was unstable. |
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