In nature, species of Orchidaceae are always associated with mycorrhizal fungi. The comprehension of fungal-plant specificity in this association can assist with the establishment of programs that focus on symbiotic propagation of orchids. Epulorhiza mycorrhizal fungi have frequently been isolated from Epidendrum secundum Jacq. Thus, the objective of this study was to evaluate the germination of E. secundum seeds and protocorm development associated with different isolates of Epulorhiza spp. Sixteen Epulorhiza fungi obtained from different E. secundum populations were used. After 44 days, all isolates promoted seed germination of this species. However, differences were observed in the efficiency in promoting seed germination and protocorm development, even among the isolates that had morphological similarities. The highest stage of protocorm development and the highest growth indexes were obtained in the presence of isolate M65. The results suggest that seed germination and protocorm development of E. secundum depend on the mycorrhizal fungi and, despite the high frequency of association between this plant and Epulorhiza, it is important to select isolates with high efficiency to establish symbiosis. Efficient isolates are useful for the production of seedlings that have economic and ornamental importance, as well as for endangered orchids.
orchid; Rhizoctonia-like fungi; symbiotic propagation
