Recloning of regenerated plantlets from elite oil palm (Elaeis guineensis Jacq.) cv. Tenera
Plant regeneration in oil palm cv. Tenera via somatic embryogenesis was conducted using regenerated plantlets as an explant source. Explants from different positions – apex, middle and basal segments of regenerated plantlets – were cultured in N6 medium supplemented with 100, 120 and 140 mg/L 2,4-dichlorophenoxyacetic acid (2,4-D) in the presence of activated charcoal. The production of embryogenic calli was affected by 2,4-D concentration and explant position; 2,4-D 120 mg/L was the most effective (62.53%) in inducing embryogenic calli from the basal segment 5 months after inoculation. After 3 months of culture in embryo maturation medium, an average of 36 ± 8 somatic embryos per embryogenic callus was obtained. When transferred to plant regeneration medium for 3 to 4 months, these somatic embryos differentiated into shoots, with ranges of 6 to 40 and 4 to 32 shoots on the medium with and without 2-isopentyladenine (6-dimethylaminopurine) (2iP), respectively. Plantlets (6 to 8 cm height) with balanced shoots and roots were obtained after 12 to 14 months. Histological analysis confirmed the initiation, development and germination of somatic embryos from explants of regenerated plantlets. Simple sequence repeat (SSR) analysis showed the genetic identity and uniformity between the first and second regenerated plantlets at five SSR loci.
Key words: Elaeis guineensis Jacq., genetic identity, regenerated plantlets, somatic embryogenesis, SSR marker.