M.A. Thesis:

Evaluation of Development a Low/Less Spored Strains of Oyster Mushroom (Pleurotus ostreatus).

The oyster mushroom Pleurotusostreatus is the third important edible mushroom in the world, following the button and shiitake mushrooms. There is an increasing interest to utilize mutation in order to obtain desirable characteristics in edible mushrooms. However, there is a scientific shortage of information available on accurate experimental details of mutation induction in oyster mushrooms. Therefore, the objective of this study was to obtain a reliable method to induce physical and chemical mutations in P. ostreatus var. floridabasidiospores through ultra violet (UV) irradiation and ethyl methane sulphonate (EMS). The findings revealed that the UV exposure at a distance of 45 cm for 120 seconds and the EMS treatment at 1.5% caused a maximum killing effect (over 95%) in basidiospores, as compared to the untreated spores. Moreover, the 50% lethality dose (LD50)wasseen to be at 41.33 seconds of the U.V exposure and the concentration 58.89% (v/v) of EMS. The findings of this study warrant further research to investigate morphological and developmental characteristics in fruiting bodies generated by the mutant spores. In addition, the experimental conditions evaluated in this study may be useful for inducing mutation through UV radiation or EMS treatment inbasidiomycete mushrooms.

Keywords: Pleurotusostreatus, spore mutagenesis, UV irradiation, Ethyl methane sulphonate,