Abstract: Fifteen Verticillium dahliae isolates were recovered from cotton in Shihezi,Northern Xinjiang. Cultu-ring characteristics,pathogenicity,pathogenicity types and ISSR genetic variation of fifteen isolates were researched. The study of culturing characteristics on PDA medium showed that the examined strains could be divided into fila -mentous type,sclerotia type and intermediate type,which accounted for 60%,26.7%,13.3%,respectively.The pathogenicity test of all strains on two cotton varieties based on artificial inoculating in chamber indicated that fifteen isolates had obvious pathogenicity differentiation. The tested isolates could be divided into strong pathogenic type, middle pathogenic type and weak pathogenic type based on average disease index of two cotton varieties. No strains were weak pathogenicity,while the strong pathogenic strains and middle pathogenic strains occupied for 73.3%, 26.7%,respectively. According to the results of special PCR primers ( ND1/ND2 and D1/D2 ), the defoliating and non-defoliating strains accounted for 33.3%,66.7%of the tested isolates,respectively.And the average virulence of defoliating strains was stronger than non-defoliating strains. The genetic variation of fifteen Verticillium dahliae isolates was large,but related to pathogenicity from ISSR fingerprint analysis. The results also showed the genetic similar coefficient of two tested strains XJ-1 and XJ-6 was high with above 99%,but the pathogenicity was signifi-cant difference and two strains XJ-8-1and XJ-8-2 with different culturing characteristics and pathogeniciy recovered Fifteen Verticillium dahliae isolates were recovered from cotton in Shihezi,Northern Xinjiang. Cultu-ring characteristics,pathogenicity,pathogenicity types and ISSR genetic variation of fifteen isolates were researched. The study of culturing characteristics on PDA medium showed that the examined strains could be divided into fila -mentous type,sclerotia type and intermediate type,which accounted for 60%,26.7%,13.3%,respectively.The pathogenicity test of all strains on two cotton varieties based on artificial inoculating in chamber indicated that fifteen isolates had obvious pathogenicity differentiation. The tested isolates could be divided into strong pathogenic type, middle pathogenic type and weak pathogenic type based on average disease index of two cotton varieties. No strains were weak pathogenicity,while the strong pathogenic strains and middle pathogenic strains occupied for 73.3%, 26.7%,respectively. According to the results of special PCR primers ( ND1/ND2 and D1/D2 ), the defoliating and non-defoliating strains accounted for 33.3%,66.7%of the tested isolates,respectively.And the average virulence of defoliating strains was stronger than non-defoliating strains. The genetic variation of fifteen Verticillium dahliae isolates was large,but related to pathogenicity from ISSR fingerprint analysis. The results also showed the genetic similar coefficient of two tested strains XJ-1 and XJ-6 was high with above 99%,but the pathogenicity was signifi-cant difference and two strains XJ-8-1and XJ-8-2 with different culturing characteristics and pathogeniciy recovered from the same diseased cotton were high similar with above 95%,indicating pathogenicity differentiation and genetic variation of Verticillium dahliae from Shihezi was complex. The study results would provide reference in order to breed cultivars and integrated control.

Key words: Cotton Verticillium dahliae, Culturing characteristics, Pathogenicity, Pathogenicity types, ISSR

CLC Number: 

• S435.62