| Fusarium head blight(FHB) is an important disease which is seriously harm to production of global wheat, mainly occured in winter wheat region of the rainy Yangtze-Huaihe River Valley and southwest and spring wheat region of northeastern at wheat flowering stage in China. Due to lack of effective disease-resistant varieties, carbendazim(MBC) and other benzimidazole fungicides were used to control FHB at flowering stage mainly for a long time. Since Shenyang Research Institute of Chemical Industry imitated MBC successfully and putted into production in1970, the pesticide formulation was used to control FHB for about30years of history in China. For existence of resistance risk due to long-term single-use carbendazim to control wheat scab, ZHOU Ming-guo research team started resistance monitoring since1985, and MBC-resistant pathogen population will develop quickly in the areas where MBC-resistant strains were detected, then controlling effect is reduced. Therefore, verifying the reason for the emergence of MBC-resistant pathogen of FHB in the Yellow River Valley where the occurrence of FHB was lighter and the use of MBC was less had important theoretical and practical significance for the formulation of measures for the prevention and controlling of hazards of resistant FHB.By the identification of species of MBC-resistant and MBC-sensitive Fusarium asiaticum and F. graminearum strains of FHB pathogens from Jiangsu, Anhui, Shandong, Henan, Hubei. Sichuan and Hebei, as well as the mycotoxin chemotype and timing analysis of detectable MBC-resistant strains, the diffusion path of MBC-resistant pathogen of FHB from East to North and Weat of China was studied.This study selected pathogens of FHB from Jiangsu, Anhui and Jingzhou Hubei in the Yangtze-Huaihe River Valley, Shandong, Henan and Hebei in the Yellow-Huaihe River Valley and Northern China and Sichuan in the southwest region to monitor their sensitivity to MBC, MBC-resistant strains were detected in Jiangsu, Anhui, Shandong and Henan. Then species of pathogen of FHB from Jiangsu, Anhui, Hubei, Shandong, Henan, Hebei and Sichuan were identified by methods of morphological and molecular biology. The results showed that the dominant pathogenic population of FHB was F. asiaticum in Jiangsu, Anhui, Hubei and Sichuan, while it was F. graminearum in Shandong, Henan and Hebei provinces. However, all MBC-resistant strains detected in Shandong and Henan were F. asiaticum.View of mycotoxin chemotype produced by the same species of pathogen of FHB had obvious geographical distribution characteristics, therefore the mycotoxin chemotypes of F. asiaticum strains from Jiangsu, Anhui, Hubei, Shandong, Henan and Sichuan were identified. The results showed that the mycotoxin chemotypes of F. asiaticum strains from Jiangsu, Anhui, Shandong and Henan were the3-AcDON and the NIV, with3-AcDON made up most of it, But they were the3-AcDON and the NIV in Sichuan, with NIV made up most of it, and the15-AcDON was produced by F. asiaticum strains from Hubei.According to types of MBC-resistant and-sensitive pathogens from different regions, as well as mytoxin chemotype and timing analysis of detectable MBC-resistent trains. We speculate that the emergence of carbendazim reisstance of FHB pathogen in Shandong and Henan may be diffused from Estern China by the ways of seed transporting and area-cross operation of combine harvester.Last it was analyzed that the genetic relationship among F. asiaticum trains from Jiangsu, Anhui, Hubei, Shandong, Henan and Sichuan by RAPD technique.2primers of good repetition and clear bands were screened from tested100random primers. Among the23polymorphic bands obtained from2selective primers,20(86.96%) were polymorphic. The cluster analysis results showed that94F. asiaticum trains were clustered into three groups,91F.asiaticum trains belong to group1. The results show that there is no significant difference among the F. asiaticum trains. The method can be used to analyze the genetic relationship among the F. asiaticum trains. |
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