Vegetative compatibility groupings of Verticillium dahliae from cotton in mainland China

One hundred and fourteen isolates of Verticillium dahliae obtained from cotton and eggplant in mainland China were successfully assigned to two vegetative 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 abundant microsclerotia and dense mycelia between compatible nitrate-nonutilizing mutants. The remaining 102 isolates were grouped into the non-defoliating VCG2, although the strength of the reaction varied; some isolates were strongly compatible with the tester strain while others were only slightly compatible. All VCG1 isolates including T9 showed the same defoliating symptom in greenhouse inoculation tests. This study confirmed the presence of the defoliating pathotype (VCG1) of V. dahliae in mainland China.