Balakrishnan, BAnitha, RKAU2019-05-022019-05-021998171407http://krishikosh.egranth.ac.in/handle/1/5810101629PGAttempts were made to collect native flora of Pleurotus spp., by doing intensive surveys for the same during monsoon periods. Among the various isolates made two efficient ones were identified and described namely, Pleurotus eous and P. petaloides. Evaluation of growth and fruiting behaviour of these isolates done following the standard method and it is proved that these isolates were amenable for large scale cultivation under Kerala conditions. The two selected isolates along with the other standard cultures procurred from various mushroom research centres of the country were subjected to detailed observations. Strain improvement programmes have been done following strain mixing hybridization and mutation techniques. One recombined strain was developed through strain mixing which has got good yield and intermediate sporocarp characters between the parents. Physical mutation was done by irradiating them with gamma radiation. Among the mutants three effective mutants were selected for their better sporocarp yield, steady yielding character and resistance against insect pests and competitor weed moulds. In the chemical mutation, one mutant having small sporocarp with long stipe and other mutant having sporocarp with very few spores have been developed. In hybridization, one hybrid was developed by pairing compatible mono spore cultures of two different species of Pleurotus which have got maximum desirable characters among the developed hybrids. Cultural characters of the selected isolates were studied and the effect of coconut milk in enhancing mycelial growth were proved. Periodical observatiori of the incidence of insect pests and competitor weed moulds in the mutants, hybrids and native isolates have been worked out. Studies on quality parameters and consumer acceptability have proved that the native isolates were comparatively better to the other species of Pleurotus obtained from various mushroom research centres of the country. Organoleptic studies of selected hybrids and mutants have been proved that they have better acceptability in the market as compared to the standard species, Pleurotus sajor-caju.ennullThesis