<Emphasis Type="Italic">In vitro</Emphasis> propagation of <Emphasis Type="Italic">Acacia sinuata</Emphasis> (Lour.) Merr. from nodal segments of a 10-year-old tree

Summary An in vitro propagation protocol has been developed using nodal explants from a mature ‘elite’ tree of Acacia sinuata. Tissue browning was circumvented by soaking surface-disinfected explants in a solution of antioxidant (238 μM citric acid). Maximum shoot proliferation (75.2%) was achieved from nodal explants collected during the December to March season in Murashige and Skoog's (MS) medium supplemented with 8.9μM 6-benzyladenine (BA), 2.5μM thidiazuron (TDZ), and 135.7μM adenine sulfate (AS) at the end of the first transfer following initial culture (60 d after inoculation). Gibberellic acid (GA₃) at 1.8 μM promoted shoot elongation. The number of shoots was increased by (1) repeated subculturing of nodal explants on fresh medium with the same composition, and (2) using microcuttings from in vitro-regenerated shoots on MS medium containing 6.6 μM BA where each node produced four shoots. When transferred to half-strength MS medium augmented with 7.4 μM indolebutyric acid (IBA) in vitro-regenerated shoots produced prominent roots. Rooted plants were hardened and successfully established in soil. This protocol yielded an average of 100 plants per nodal explant over a period of 3 mo.