PENGARUH JENIS EKSPLAN DAN KOMBINASI ZAT PENGATUR TUMBUH (ZPT) TERHADAP INDUKSI KALUS Begonia bimaensis Undaharta & Ardaka SECARA IN VITRO

Begonia bimaensis Undaharta & Ardaka is a potential ornamental plant, and currently known only from one population in Sumbawa. Propagation programs, both conventional and in vitro culture are necessary to ensure its conservation. The aim of this research is to observe the effects of explant types and plant growth regulator combination (2,4-D and kinetin) in inducing callus from B. bimaensis leaf in vitro. Callus induction was initiated from three parts of leaf explant, namely petiole, leaf base, and leaf lamina. The explants were planted on Murashige & Skoog (MS) medium with addition of 2,4-D and kinetin. Concentrations of 2,4-D were 0, 0.5, and 1 ppm, while kinetin concentrations were 0, 1, and 2 ppm. Each treatment was replicated 10 times. Results showed that leaf base was the best explant used for callus induction. Medium D1K2 (MS + 1 ppm kinetin) showed the fastest time for callus induction that was at 20 days after planting. The highest percentage of callus production (100%) was found on D1K3 (MS + 2ppm kinetin); D2K2 (MS + 0.5ppm 2,4-D + 1 ppm kinetin); D2K3 (MS + 0.5ppm 2,4-D + 2ppm kinetin) and D3K2 (MS + 1ppm 2,4-D + 1ppm kinetin).