Vegetative compatibility group of Fusarium species associated with root and stem rot of Orchid

F. oxysporum, F. proliferatum and F. solani isolates were recovered from root and stem rot of orchid. The isolates were placed into vegetative compatibility group (VCG) based on pairing of complementary mutants. From complementation tests, all F. solani isolates did not form heterokaryons and was therefore heterokaryon self-incompatible. For both F. oxysporum and F. proliferatum isolates, four VCG were identified. The results suggest that variation exist among the F. oxysporum and F. proliferatum isolates from root and stem rot of orchid.