Instability of homokaryotic strains of Agaricus bisporus

A few homokaryotic strains of Agaricus bisporus has been investigated during the one year period that helped to offer classification of morphological instability. Several types of instability were depicted and the main division is based on ability to preserve or lose the motherline in process of cultivation. Presence of the mating type switching mechanism (such as in yeasts and some basidiomycetes) were also looked for in one heterokaryotic strain, obtained from homokaryotic mycelium, We suggest that if such mechanism is present it is realised only through copying of a parent allele from a silent to active mt-locus.