RESUMO
In vitro stem segments of Pelargonium radula cultured for callusing then differentiated into somatic embryos and subsequently regenerated plantlets. Initiation of callus was observed in culture medium containing low concentrations of the plant growth regulators, 2,4-dichlorophenoxyacetic acid (2,4-D) and/or α-naphthalene acetic acid (NAA). At 0.2 mg/L 2,4-D and 0.2 mg/L NAA was showing the highest rate (92%) of callus induction. The callus showed no sign of browning after sub-cultured. Sub-culturing the callus onto medium with 0.2 mg/L 2,4-D showed the highest in proliferation rate resulted 13.45g weight of callus. The presence of agar at 6 g/L and 0.5 mg/L Gibberellic acid (GA3) improved the regeneration of the somatic embryos, which produced maximum number of plantlets (15 plantlets). Agar with concentration of 9 to12 g/L increased the incidence of browning. The former medium was more successful in plantlet regeneration when the selected embryos were subsequently transferred to regeneration medium with 3 g/L agar, 0.5 mg/L GA3 and 0.5 mg/L Benzylaminopurine (BAP).