The objective of this work was to develop techniques of in vitro regeneration for mahogany (Swietenia macrophylla), using epicotyl segments, inverted epicotyls and leaf explants from mahogany plantlets germinated in culture medium. Also, the best concentration and time and sterilizing agent for seed sterilization were determined, as well as the best seed sowing position for germination. After tegument removal, seeds were sterilized in sodium hipochlorite solution at 0; 2,5 and 5,0% (v/v) concentrations, kept soaking for 10, 20, 30 and 40 minutes and inoculated in the culture medium in two positions: a) position 1 - with the concavity of the flat part turned upward, and b) position 2 - with the concavity of the flat part turned down. After sowing, seeds were kept in growth room with controlled temperature (±26 ± 2ºC) and continuous dark. An entirely random factorial design, with 3 x 4 x 2 (sodium hipochlorite levels x soaking times x seed position), totaling 24 treatments with 3 repetitions was used. The germination stage and microorganism contamination were evaluated at 12, 18, 24 and 30 days after germination. The best treatments were seed sterilization in 2,5 and 5% sodium hipochlorite for 30 and 20 minutes, respectively, and both inoculated in position 2. These treatment also presented the highest germination rate (48%) and the lowest rates of microorganism contamination (15 e 10% respectively). As for position, a significant difference was detected for 24 and 30 days after sowing, with the largest means for seeds inoculated in position 2.
Swietenia macrophylla; mogno; in vitro germination; seeds sterilization; sowing position
