In vitro plantlet regeneration from mature zygotic embryos of Pinus wallichiana AB Jacks

Plantlet regeneration was achieved in blue pine (Pinus wallichiana A.B. Jac ks) by organogenesis of mature zygotic embryos. The effect of various basal media and five cytokinins on adventitious bud induction, development and e longation was investigated. Half-strength Douglas fir cotyledon revised med ium. (DCR) supplemented with 2.5 mu m N-6-benzyladinine (BA) and 0.025 mu M thidiazuron was found to be most effective in inducing adventitious buds. The effect of a BA pulse treatment was also tested, and the bud-forming cap acity of each treatment was quantified. The elongation of adventitious buds was achieved on hormone-free half-strength DCR medium containing 2% sucros e and 0.05% activated charcoal. Rooting was induced in the elongated shoots with a 6-h treatment of indoleacetic acid and indolebutyric acid solutions (1 mM each). Rooted shoots were transplanted in the greenhouse for hardeni ng and their survival percentage was 64.4 after 5 weeks and 45.7 after 6 mo nths.