Zones of Inhibition

The cultivated mushroom, Agaricus bisporus, like all mushrooms, toadstools and bracket fungi produces spores known as basidiospores by a form of sexual reproduction. These basidiospores are formed on the gill structures of the mushroom and are produced from the fusion of two nuclei from different parental strains.

For some fungi, fertilisation can take place between any two individuals and even within the same individual. In other fungi, 'male structures' can only combine with 'female structures' of a different but sexually compatible piece of mycelium.

When strains are compatible the hyphae can intermingle and grow together. However, if hyphae from incompatible strains of the same species grow in close proximity, the incompatible mycelia keep apart from each other and avoid contact. This creates a zone of inhibition.