Development of improved strain in species of Pleurotus by gamma irradiation

The oyster mushroom (Pleurotus spp.) is the second important edible mushroom in the world, with 19 per cent contribution to total mushroom production (Sharma et al., Mushroom Res 26(2):111-120, 2017). The cultivated mushrooms face the problems like loss of genetic diversity and strain degeneration (Wang et al., Curr Microbiol 65(4):424-431, 2012). Thus to enhance the productivity within short duration, three species of Pleurotus namely Pleurotus djamor, Pleurotus florida and Pleurotus ostreatus were gamma irradiated at 20 and 25 Gy at 9.779 kGy/h and performance of mutants followed by three generation of selection in paddy straw substrate were observed. Biological efficiency (BE) of P. djamor mutants irradiated at 20 Gy was increased by 9.25 per cent. The number of days taken for primordial initiation was also reduced by 1 day compared to P. djamor. P. florida irradiated at 25 Gy recorded increase in sporocarp size over P. florida. The biological efficiency of P. ostreatus irradiated at 25 Gy was improved by 12.89 per cent and there was earliness in primordial initiation by 3 days compared to P. ostreatus. The polymorphism per cent was analysed by Random Amplified Polymorphic DNA (RAPD) and revealed that P. djamor, P. florida and P. ostreatus had 16.70%, 25% and 22% polymorphism with their respective improved strains.