An efficient plant regeneration system for manuka (Leptospermum scoparium) from seedlings

Abstract

Leptospermum scoparium, commonly known as manuka, is the most important indigenous shrub species in New Zealand, and has probably undergone the most varied development as an economic plant in the indigenous flora. The purpose of this research was to establish an efficient regeneration system for manuka from seedlings. Shoot tips and nodal segments of manuka seedlings were cultured on Murashige and Skoog (MS) medium, supplemented with several concentrations of 6-benzyladenine (BA) or in combination with gibberellic acid (GA3). The best results for shoot proliferation were obtained with 2.0 mg l-1BA and 0.1 mg l-1GA3, resulting in 89.3% shoot formation and a maximum shoot number (5.23 ± 0.06) per explant. Regeneration shoots were transferred to halfstrength MS medium supplemented with several concentrations of α-napthalene acetic acid (NAA) or indole-3- acetic acid (IAA) for rooting. The best rooting was achieved with 0.5 mg l-1NAA, resulting in a 96% root formation and a maximum root length (2.26 ± 0.41 cm). When transferred to outdoors, the well-rooted plantlets from NAA had a survival rate of 87.5% and continued to grow.