Twenty-seven Fusarium oxysporum isolates were studied by RAPD-PCR and isozyme analyses. Thirteen isolates were from barley
and the rest from different hosts, most of which were dicotyledonous plants. All isolates could be distinguished from each other by
RAPD-PCR analysis, and clustered into seven groups in NJ and parsimony consensus trees. Isozyme analysis detected polymorphism
in five of the six enzymes and the isolates could be divided into 26 different electrophoretic groups. Five groups were supported by
high branch support and bootstrap values in the approximate support tree of combined RAPD-PCR and isozyme data. These five
groups were found also in NJ and parsimony consensus trees. The matrices from RAPD-PCR and isozyme data proved to be
incongruent, but they did not totally disprove each other. Some correlation was found between geographical origin and
phylogenetic relationships of isolates collected from barley. Representatives of the main clades of phylogenetic trees, were further
studied by rDNA RFLP and rDNA sequence analyses, together with isolates of other Fusarium species. Isolates of F. oxysporum and
F. avenaceum formed distinct groups in the phylogenetic analyses, except for two isolates of F. oxysporum which were grouped with
isolates of F. redolens.