Vegetative compatibility groupings of Verticillium dahliae from cotton in mainland China

One hundred and fourteen isolates of Verticillium dahliae obtained from cot ton and eggplant in mainland China were successfully assigned to two vegeta tive compatibility groups (VCGs) except for one self-incompatible isolate. Eleven isolates were strongly compatible with T9, the tester strain of the cotton defoliating pathotype, forming a linear growth of wild type with abu ndant microsclerotia and dense mycelia between compatible nitrate-nonutiliz ing mutants. The remaining 102 isolates were grouped into the non-defoliati ng VCG2, although the strength of the reaction varied; some isolates were s trongly compatible with the tester strain while others were only slightly c ompatible. All VCG1 isolates including T9 showed the same defoliating sympt om in greenhouse inoculation tests. This study confirmed the presence of th e defoliating pathotype (VCG1) of V. dahliae in mainland China.