Performance of Differents Genotyps of Brazilian Orchid Cultivation in Alternatives Substrates

Two native Brazilian orchid especies, Oncidium baueri and Maxillaria picta, were grown in different substrate mixtures. The plants were cultivated in ceramic pots in a greenhouse with 50 % of shadind light and watered three times a week. The following substrates were used: 1) de-fibered xaxim; 2)xaxim cubes; 3) vermiculite; 4) carbonized rice husk; 5) charcoal; 6) charcoal + carbonized rice husk; 7) crocks; 8) vermiculite and charcoal; 9) vermiculite + carbonized rice husks; 10) extruded polystyrene + charcoal; 11) pine bark + charcoal + extruded polystyrene; 12) vermiculite + carbonized rice husks + extruded polystyrene + charcoal; 13) pine bark. The substrate ratio was 1:1 in the mixture. NPK 10-10-10 leaf fertilizer was applied every thirty days and castor bean cake and bone powder organic fertilizer were applied every ninety days. A randomized complete block design was used with 10 replications. Growth and rooting were assessed after eight months. The best alternative substrate to O. baueri was vermiculie and the best alternatives substrates to M. picta were vermiculite and charcoal and vermiculite + carbonized rice husks. Key words: Orchidaceae, Maxillaria picta, Oncidium baueri, growing media Author for correspondenc