Heterokaryosis in Fusarium oxysporum f.sp. lycopersici.

Intra-isolate and inter-isolate heterokaryons were synthesized between auxotrophic mutants of Fusarium crown rot, 'purple variant' and the wilt isolates. This is the first report of intra- and inter-isolate heterokaryons in Fusarium oxysporum f.sp. lycopersici. Conidial ratios determined for several heterokaryons between different mutants of the Fusarium crown rot organism showed that the ratio is constant for each heterokaryon and that the ratio usually is in favour of one of the mutants.