An efficient mass propagation protocol for Aegle marmelos (L.) Corr. through In Vitro generated shoot tips

Aegle marmelos (L.) Corr. commonly known as ‘beli’ in Sri Lanka is an important fruit tree with extensive medicinal uses in indigenous medicinal systems. The plant is conventionally propagated by seeds which have short viability and low germination percentage. Vegetative propagation through root suckers is slow and challenging. Root being the major medicinally valuable part, destructive harvesting poses a serious threat to the sustenance of the tree. Therefore, the aim of this study was to develop an efficient mass propagation protocol for A. marmelos through in vitro generated shoot tips. Shoot tips taken from three weeks old in vitro grown seedlings of A. marmelos were cultured on Murashige and Skoog (MS) medium supplemented with 6-benzylaminopurine (BAP) (1.0 mgL^-1 or 2.0 mgL^-1), kinetin (0.5 mgL^-1 or 1.0 mgL^-1), and thidiazuron (TDZ) (0.25 mgL^-1 and 0.5 mgL^-1) either alone or in combination. The highest mean number of shoots per shoot tip (16.73) and highest mean total length per shoot tip (10.58 cm) were observed on MS medium containing 1.0 mgL^-1 BAP and 1.0 mgL^-1 kinetin. In this study poor response of shoot proliferation was observed when using MS medium supplemented with TDZ alone. Shoot formation was optimum in the fifth week from establishment. In vitro derived shoots were transferred to root induction medium consisting of half-strength MS medium supplemented with three different concentrations of indole-3-butyric acid (IBA) (1.0, 1.5, 2.0 mgL^-1) with or without 5% activated charcoal. Highest rooting was achieved in the medium supplemented with 1.0 mgL^-1 IBA with activated charcoal. Rooted plantlets were acclimatized using coco pellets and transferred to the soil with 80% survival rate.