Development of sporeless/low sporing strains of Pleurotus through mutation

The sporophores of Pleurotus are gymnocarpous and continuously release spores in the atmosphere causing respiratory allergies like hay fever and farmer's lung disease among workers. The allergy is caused by the antigens present on the walls of the spores. Apart from this, during commercial production, these spores settle on the fruit bodies, germinate and form a velvety film which gives an unpleasant appearance to the mushrooms. The spores emitted may include new genotypes likely to attack wood or trees. Spore allergy is one of the most important limiting factors for the large scale cultivation of this species. Different approaches are being adopted at IIHR for the production of commercial sporeless/low-sporing strains of Pleurotus to alleviate the spore allergy problem. Attempts were made during the present invvestigation to produce sporeless or low-sporing mutants through u.v. mutation. Mutation of the mycelium did not yield the desired results. Mutation of the spores of Pleurotus sajor-cajun yielded an extremely low-sporing mutant after 75 min exposure. The character has been found to be stable for more than 10 generations of subculturing.