Somatic embryogenesis from zygotic embryos and thin cell layers (TCLs) of Brazilian oil palm (Elaeis guineensis × Elaeis oleifera)

Oil palm hybrid BRS Manicoré is important for plantations in the north of Brazil, as it is resistant to fatal yellowing and is compact. Seed germination is slow and reduced, so somatic embryogenesis is a promising alternative for its propagation. Two kinds of starting explants were used: Zygotic embryos (ZE) and thin cell layers (TCL) from the base of seedling aerial parts. Two culture medium formulae were compared (Y3 and modified MS), and several growth regulators (2,4-D, Picloram, BA, 2iP), putrescine and activated charcoal (AC) were used during the different stages. Somatic embryos (SE) were obtained from ZE-derived embryogenic masses cultured on Y3 medium with or without 2,4-D (9 μM) + 1000 μM putrescine and 40% were converted into seedlings in the Y3 medium supplemented with 2 g.L-¹ AC and without growth regulators, under light. SE developed in 49 to 53% TCL-derived calli and 50% of them were converted into seedlings in the same conditions described for ZE calli. The yield of both processes was compared, showing the superiority of TCL explants for SE production.Key words: Y3 culture medium, clonal propagation, putrescine, thin cell layer