Determination Of Cross-Pathogenicity Of Verticillium Dahliae Different Crops And Antifungal Of Fungicides

The Verticillium wilt is one of the most harmful soil-borne vascular diseases in the world,mainly caused by the infection of Verticillium dahliae.The pathogen V.dahliae has a wide range of hosts,which can infect cotton,many solanaceous plants and cruciferous plants,etc.And causes huge economic losses every year.Studies have shown that Vdahliae often differentiates in pathogenicity in the process of interacting with the host and living environment,and there is a lack of effective drugs against Verticillium wilt in the production.The isolation and identification of V.dahliae from different crops,and the study of its pathogenic composition,culture characteristics,pathogenic type and pathogenicity differentiation,can lay a theoretical foundation for the prevention and control of Verticillium wilt in crops.This paper collected and identified Verticillium wilt of cotton,eggplant,potato,sunflower and other crops from Henan Province,Shandong Province,Inner Mongolia Autonomous Region,etc.,and carried out the cultivation characteristics,genetic characteristics,and pathogenicity differentiation of V.dahliae strains of cotton and eggplant.In the study,the cross-pathogenicity of V.dahliae isolates from cotton,eggplant and potato was studied,and fungicides that could effectively control the occurrence of Vdahliae in cotton were screened.The following results were obtained:(1)From 2018 to 2019,72 strains of Vdahliae from cotton,53 strains from V.dahliae from eggplant,and 5 V.dahliae strains from sunflower isolated and identified from 2018 to 2019 by morphological and molecular biological identification,While the 10 strains were identified for V.albo-atrum from Inner Mongolia Autonomous Region.(2)Observation of the culture characteristics of 72 cotton V.dahliae colonies showed that the cotton V.dahliae mycelial type accounted for 25%;the intermediate type accounted for 45.8%;the sclerotium type accounted for 29.2%,indicating that the intermediate type of the cotton V.dahliae in Henan and Shandong areas is main type.Among 53 strains of eggplant Vdahliae,the hyphae type accounted for 30.2%;the intermediate type accounted for 32.1%;and the sclerotium type accounted for 37.7%,showed that the strains of the three culture types were widely distributed in the population of Vdahliae.(3)The defoliating(D)pathotype and nondefoliating(ND)pathotype(ND)specific primers D-1/D-2 and ND-1/ND-2 of V.dahliae were used to identify the pathotype of V.dahliae.The results showed that the cotton V.dahliae isolates in Henan and Shandong areas are defoliating pathotype strains,which occupied an absolute dominant position.There were 31 defoliating pathotype(D)strains of V.dahliae in eggplant,accounting for 58.5%,and 22 nondefoliating(ND)pathotype strains,accounting for 41.5%,which indicated that defoliating pathotype(D)strains also accounted for a considerable proportion of V.dahliae.(4)The mating type genes of V.dahliae were detected using the mating type genes MAT1-2-1 and MATT-1-1 specific primers VdMAT12F/VdMAT12R and VdMAT111F2/VdMAT111R3.The mating type genes of V.dahliae isolates are all MAT1-2-1,indicated that the cotton and eggplant V.dahliae strains mainly asexually reproduced.(5)Using the race 1 specific primers VdAve1F/VdAvelR of V.dahliae and race 2 specific primers VdR2F/VdR2R,PCR amplification of the V.dahliae strain was carried out to determine the physiological race of the strain.The results showed that the cotton and eggplant V.dahliae isolates belong to race 2.And didn’t carry the avirulence gene Avel.(6)Using the dip-root inoculation method,the pathogenicity of 32 cotton V.dahliae strains on cotton and 31 V.dahliae strains from eggplants on eggplant on diseaseresistant and susceptible varieties was measured,The results indicated that the pathogenicity between the strains of V.dahliae from cotton and eggplant differentiated.And the pathogenicity of V.dahliae is not related to its culture characteristics,colony growth rate and geographic origin.(7)The cross-pathogenicity of 10 strains of V.dahliae on cotton,10 strains of V.dahliae on eggplant,and 10 strains of V.dahliae on potato were tested on cotton and eggplant seedlings.The results showed that the pathogenicity of V.dahliae differentiated on different crops.(8)The antifungal effects of two fungicides 80%eticillin and 30%hymexazol on Vdahliae were determined.The EC50 value of 80%eticillin was 0.03-0.05 mg/L,and the EC50 value of 30%hymexazol was measured.0.25-0.35 mg/L,indicating that 80%Ethylicin and 30%Oxymethalin have a good antifungal effect on Vdahliae.