| Fusarium head blight(FHB) is a worldwide disease. In china, it always popular in wheatarea of the middle and lower reaches of ChangjiangRiver, while it becomes one of the most important diseases of wheat in Shandong in recent years. FHB not only declines the production of wheat, but also generates mycotoxin, which is harm to human and animal.This experiment wants to clear of the population structure andmycotoxin chemotypes, analyze the virulence of strengthpathogenic groupand sensibility to different fungicides. The main research results are as follows:1. We collected more than 300 samples of FHB from 28 counties and cities in shandong during 2014~2015, separating and gaining 338 strains of FHB. According to the gathering place, we selected 120 strains as representative strains. And its population structure and mycotoxin chemotypes have been studied through PCR assay. The result shows that all strains belong to Fusariumgraminearum, 108 strains belong to F. graminearum, and the other 12 strains are F. asiaticum. F. graminearum is the dominant population with a pecentage of 90; F. asiaticum ismainly distributed in the middle and lower reaches of the Yangtze river This time is firstly detected in Shandong and its distribution has no relationship with preceding crop. Chemopype detection result shows 118 strains have deoxynivalenol( DON) chemotypes, while the oher two strains have nivalenol( NIV) chemotypes. Among the 118 DON strains, 101 strains are 15-acetyldeoxynivalenol(15-AcDON) and 17 strains are 3-acetyldeoxynivalenol(3-AcDON). There is no one-to-one correspondence relationship between population structure of Fusarium head blight and its mycotoxin chemotypes.2. According to different gathering place, we selected 16 stength strains from 120 experement as representative, using single flower instillation to measure its pathogenicity. The virulence assay result shows thatdifferent strains have an obious pathogenicity differentiation. What is more, wechoosed two strains and determined FHB resistant levelof32 wheat strains by using the same method. Results show that the 24 strain has a middle resistance, 5 and 8 strains belong to middle sensitive varieties, and the others belong to sensitive and highly sensitive varieties. Highly resistant and immune varieties have not been found yet.3. Tebuconazole and difenoconazole are two kinds of commonly used broad-spectrum fungicides, which are mainly used to prevent and treat FHB as well as other fungal diseases. According to the gathering place of different strains, we select 62 strength strains and measure its sensibility to tebuconazole and difenoconazole by observing the inhibition to colony diameter. The results show that 62 strains' average value of EC50 to tebuconazole is 0.546±0.276 ?g/m L, and all the experiment strains belong to sensitive strains, which can be controled at an agent concentration of 1.4 ?g/m L; On the other hand, 62 strains' average value of EC50 to difenoconazole is 0.671±0.354 ?g/mL, and all the experiment strains belong to sensitive strains. As a conclusion, FHB has not produced resistance to these drugs in Shandong.4. People usually plant wheat and corn in one yearin Shandong,and maize stalk rot has a serious happen as well as harm. In order to clearing of pathogenic funji'correlation between FHB and maize stalk rot, we collected 50 sample of maize stalk rot from 8 plots where gathered FHB pathogenic funji, and seperated 105 pathogenic funji. The result shows that F. graminearum has the percentage of near 2/3,and its population structure andmycotoxin chemotypesare the same as F. graminearum that seperated from FHB in Tai'an. The evolutionary tree shows high affinity. As a result, we speculate that crop rotation between wheat and corn might aggravate occurrence and damage of FHB when the weather is optimum at flowering period. |
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