CULTURAL DEGENERATION IN 2 FUSARIUM SPECIES AND ITS EFFECTS ON TOXIGENICITY AND CULTURAL MORPHOLOGY

Ten isolates each of Fusarium compactum and Fusarium acuminatum subsp. armeniacum were sub-cultured using single hyphal tips (HT) and single germinated macroconidia (SM) for ten generations. Cultural degenerati on to intermediate, mycelial or pionnotal cultures was observed in a l arge proportion of cultures of both fungi, but pionnotal cultures were only produced in sub-cultures using SM transfers. Some reversion of i ntermediate and mycelial cultures to the wild type was observed. Howev er, pionnotal cultures once formed were stable and did not revert to o ther cultural types in later generations. The toxicity and trichothece ne production of degenerate cultures were comparable to those of wild type cultures. Colony diameters of pionnotal cultures were reduced in comparison with wild type cultures. The pigmentation of all degenerate cultures remained consistent with that observed in wild type cultures . Chlamydospore production was independent of cultural degeneration, a s all cultural types produced chlamydospores equally well as the paren tal wild types.