Optimization of Conditions for Mass Production of Orchid Mycorrhizal Fungi (OMF) Inoculants

The study determined the optimum conditions for mass production of OMF inoculants. Extracts from each of the five different locally-available materials (sorghum, SHE; rice bran, RBE; sawdust, SE; and fern chips, FE and combinations of RBE and SE) for isolation of pure culture from tissue and spores and subsequently production of “mother culture” were evaluated. Four locally available substrates (sawdust, fern chips, sorghum and rots) combined with rice bran for spawn production and interaction of temperature and substrate for fruiting bodies formation were likewise assessed. Combination of extracts of rice bran and sawdust at 1:1 ratio and rice bran alone were found to be the most suitable media for multi-spore and tissue isolations and production of “mother culture”. Sawdust and fern chips each mixed with rice bran at 1:1 ratio were found to be the best substrate for spawn production. These substrates were fully colonized with OMF mycelia four weeks after incubation at room temperature. Exposure of substrate (sawdust + rice bran) fully colonized with mycelia to cold temperature favored primordial initiation for a shorter period of time. Larger and heavier basidiocarps were obtained from these substrates.