In vitro regeneration competence of a Sumbawa indigenous plant, Begonia bimaensis Undaharta & Ardaka, using leaf explants

Begonia bimaensis Undaharta & Ardaka, an indigenous plant to Sumbawa, Indonesia, is classified as vulnerable by the IUCN Red List criteria. Thus, an appropriate strategy is necessary to ensure the plant’s survival, including tissue culture. In this study, B. bimaensis leaves were used as a source of explants for callus induction in MS media containing 2 mg L^-1 IAA, 2 mg L^-1 NAA, 3 mg L^-1 BA, and 0.5 mg L^-1 kinetin. After the callus had formed, it was moved to MS medium without growth regulators for two weeks. The calli were then transferred to a new MS medium containing different amounts of NAA and BA for regeneration. As a result, B. bimaensis leaf explants swelled after 13 weeks on callus induction media. Three media (NAA-BA 0-0, 1-0, 2-0 mg L^-1) successfully regenerated all explants into shoots and roots. NAA-BA 0-0 mg L^-1 resulted in the fastest shoot formation, whereas the NAA-BA 1-0 mg L^-1 treatment resulted in the quickest root emergence. Media with NAA-BA 1-0 mg L^-1 produced the greatest number of shoots (83.2±12.1). NAA-BA 1-0 mg L^-1 and 2-0 mg L^-1 were the treatments that resulted in the longest and most abundant roots. We conclude that NAA and BA effectively regenerate shoots and roots in B. bimaensis explants. Small amounts of auxin may benefit in in vitro regeneration of this species.