4. ConclusionThis study comprised three experiments. In the first experiment, effectivenessof three concentrations of ground oat (1, 5, or 10 g/l) inOMAinoculatedwith the orchid mycorrhizal fungus (T. deliquescens), uninoculatedOMA (10 g/l of oat) and 1/5MS on promoting seed germination ofD. lindleyi were compared. Higher oat concentrationswere found to enhancegermination and protocorm development of D. lindleyi. The OMAcontaining 10 g/l of oatwith mycorrhizal inoculation also outperformed1/5MS. In the second and third experiments, the use of common orchidcultivation substrates as alternative media for in vitro symbiotic orchidseed germination was investigated. We demonstrated that sphagnumpeat moss inoculated with T. deliquescens in plastic containers couldbe used to germinate seeds of D. fimbriatum to advanced seedlingstage, although the germination percentages were low, probably dueto the waterlogged characteristic of the peat moss and low ventilationof the plastic boxes. Therefore, in our last experiment, we used themixtureof peat moss and coir dust packed in Petri dishes to solve the mentionedproblems and compared the effectiveness of this systemto OMAand 1/5MS. The three treatments resulted in similar germination percentagesbut the symbiotic methods were more effective than 1/5MSin promoting protocorm development of D. findlayanum. The findingsof this study can be used to improve symbiotic germination media andthey encourage the use of symbiotic germination method as mean fororchid seed propagation.AcknowledgementsWe thank Mr. Phunsak Kidmung, Miss Daroonsri Maneesorn andMr. Auttapon Taluengjit for providing the orchid capsules. This workwas supported by the Thailand Research Fund and Mae Fah LuangUniversity (RSA5580040).