In vitro plant regeneration from nodal segments of the spontaneous F1 hybrid Santalum yasi × S. album and its parents S. album and S. yasi

Abstract

An in vitro culture protocol through somatic embryogenesis has been established for the F1 hybrid, Santalum yasi × S. album, S. album , and S. yasi. The spontaneous F1 hybrid, Santalum yasi × S. album and its maternal S. yasi and paternal S. album are economically important plant species due to their highly valued perfume oils. In vitro plant regeneration from nodal segments of these species and hybrid was studied. The optimal basal medium for shoot multiplication was Murashige and Skoog (MS) supplemented with 2.22–4.44 µM 6-benzyladenine (BA) and 1.07–2.69 µM α-naphthaleneacetic acid (NAA) in S. album × S. yasi and S. album or the same concentration range of BA and 2.85–5.71 µM indole-3-acetic acid for S. yasi. Lower concentrations of BA and NAA induced adventitious roots in S. yasi × S. album and S. album. Embryogenic callus was induced when S. album × S. yasi and S. album nodal segments were cultured on MS medium supplemented with 4.52–9.05 µM 2,4-dichlorophenoxy acetic acid (2,4-D). Friable embryogenic callus of S. yasi × S. album was subcultured onto MS medium containing 0.89 µM BA, 0–0.27 µM NAA or 1.44–5.77 µM gibberellic acid (GA3) for somatic embryo induction, maturation and germination. A low concentration of indole-3-butyric acid (0.98–2.46 µM) effectively lengthened stunted roots of germinated S. yasi × S. album somatic embryos. In S. album, embryogenic callus produced many globular somatic embryos when cultured on half-strength MS medium containing only 0.44–0.89 µM BA. These globular somatic embryos were germinated and matured on half-strength MS medium supplemented with 0.44 µM BA and 1.44 µM GA3. On MS medium free of plant growth regulators, S. album plantlets regenerated within 20–30 days. This study provides new opportunities for the exploitation and utilization of high-yielding Santalum species and hybrid.