Modulation of Adventitious Root Formation in Boswellia serrata Stem Cuttings to Exogenous Application of different Root Promoting Hormones

Boswellia serrata Roxb., commonly known as Salai in India and Indian frankincense globally, is widely distributed across 17 of the 28 Indian states. Despite its extensive range, the species is not having good status in India and at the same time it is Critically Endangered in Sri Lanka, primarily due to overexploitation and habitat loss. Given the species' current status, natural regeneration in the wild remains poor. Study was conducted to evaluate the rooting response of B. serrata cuttings treated with indole-3-butyric acid (IBA) and α-naphthalene acetic acid (NAA). In vegetative propagation trials, IBA at 5000 ppm produced 21.67% callusing and 11.67% rooting success, followed by IBA at 4000 ppm, with 18.33% callusing and 10.00% rooting. The highest sprouting rate (28.33%), number of roots (4.33), total mean root length (220.04 cm), and mean dry weight of roots (115.00 mg) were observed at IBA 4000 ppm. In contrast, NAA treatments showed peak rooting success (3.33%) at both 4000 and 5000 ppm, with lower concentrations (2000-3000 ppm) resulting in reduced rooting (1.67%). Control cuttings failed to produce any roots. This study highlights the efficacy of IBA, particularly at 4000 to 5000 ppm, in promoting effective vegetative propagation of Boswellia serrata, offering a promising approach to aid the conservation and sustainable management of this valuable species.