摘要:The aim of study was determined to relationship between on the seed surface microflora and reaction to Verticillium wilt of cotton cultivars with different gossypol levels. Thirteen cotton cultivars were examined gossypol level and the seed surface microflora of the cotton in vitro. Then, these culti-vars were observed susceptibility to non-defoliating (Vd11 isolate) and defoliating (PYDV6 isolate) pathotypes of Verticillium dahliae Kleb. in vivo. Cultivars were significant at (P<0.05) probability level for disease intensity values in vivo and gossy-pol values in vitro. While the highest gossypol value was determined in ^Gloria^ cultivar (Goss-y-pium hirsutum L.) with a 1.669 ^g mL-1and resistant control uGiza 45^ (Gos^ypium barbadense L.) with a 1.343 ^g mL-1, the lowest gossypol value was found in ^Gossypolsuz Nazilli^ (0.196 ^g mL-1) and susceptible control ^^ukurova 1518^ (0.484 ^g mL-1) of G. hirsutum L. While the lowest of disease intensity value was observed Vd11 isolate and PYDV6 isolate in the highest gossypol, resistant control “Giza 45” cultivar (0.30-1.11). The highest disease intensity values were found in the lowest gossypol, “GossypolsUz Nazilli” cultivar (2.24-2.82) and susceptible control ^^ukurova 1518” cultivar (2.00-2.63), respectively. Fungus species were isolated in high and low gossypol of cotton seeds at the same rate.