Casca de arroz e 6-Benzilaminopurina na multiplicação in vitro de Oncidium baueri

The aim of the work was to evaluate the use of substrates as support agents in substitution of agar in the medium and concentrations of 6-benzylaminopurine (BAP) in the in vitro multiplication of Oncidium baueri. Two factors were evaluated: types of substrates (rice husk, carbonized rice husk and agar) and BAP concentrations (0, 1, 2 e 3 mg L-1). After four months, it was evaluated the survival percentage; average leaves number; average sprout number; fresh and dry mass aerial part of the explants. Regarding the percentage of survival and the number of leaves, the agar showed the highest averages. For the number of shoots, the carbonized rice husk and the agar did not differ statistically. The highest fresh mass was obtained using 1 mg L-1 BAP and agar. For the dry mass, agar showed the highest average when associated to 1 mg L-1 of BAP, however, no significant difference was observed at 0 and 3 mg L-1. Thus, the use of agar and 1 mg L-1 of BAP is recommended. However, as an alternative to agar carbonized rice husk without the growth regulator, but a reduction of up to 35.8% in the survival rate and 53.8% in the number of in in vitro multiplication of O. baueri.