Reversion of UV light morphological and colour mutants of Trichoderma viride

By using UV light 13 years ago from Trichoderma viride 8-7 Pers. ex S. F. Gray 82 colour and morphological mutants were prepared. The reversion of these mutants was high and in 1985 only 26 stable mutants (i.e. 32%) could be used for genetic studies. In 1991, from these 26 mutants we had only 6 stable types (i.e. 7.3% from the original state). These mutants were permanently transferred on fresh CzDA medium every 3-4 months and checked for morphology, growth, conidiation, heterokaryons and diploids production. The group of mentioned mutants was enlarged with mutants which were after 3-4 transfers on fresh medium, preserved dried to the present time. The largest differences were observed in microscopic appearance of colonies. Differences between growth rates, intensity of conidiation were comparable with those made 13 years ago.