In this experiment, Gamma radiation was used for induction genetic diversity in white button mushrooms for achieving genotype(s) with desirable traits such as high yield and quality. Gamma radiation at dose 0, 100, 200, 300, 400, and 500 Gy per hour in air from a Cobalt 60 source were conducted on spreading spores on culture medium at room temperature (28 ± 2°C) at the Iran Atomic Energy Organization. 20 variants were selected based on physiological and mycelium growth rate differences for each gamma dose (totally 100 variants). The variants were incubated in compost. The experiment was conducted in a completely random design with three replicates. ANOVA results showed that significant differences among variants for days to complete spawn running, days to pin production and fruit body harvest, number of fruit body, fruit weight, yield, dry matter, and activation of laccase and manganese peroxidase enzymes (p<0.05). The lowest time for pin production and fruit body harvesting was observed in GR55 and GR63. Seven variants had higher Fruit body weight and GR54 lower than control. The results showed that gamma irradiation generated variation in the final yield of the three-flash harvest. Six variants, GR3, GR4, GR9, GR61, GR74, and GR72 were produced about 30% significantly more yield than the control. The results showed that the diversity in the white button mushroom can be improved by using
