Abstract

Regeneration of the coconut (Cocos nucifera L) through indirect somatic embryogenesis using 9 to 12 months embryos explants was established in Y3 medium supplemented with 100 to 250 µM 2,4 -dichlorophenoxyacetic acid (2, 4-D) alone and in combination with gibberellic acid (GA₃), 6-benzylaminopurine (BAP) and thiadiazuron (TDZ). The highest callus induction (100%) was observed in medium containing 150 and 250 µM 2, 4-D + 5 µM BAP while the least was in 2, 4-D alone (16.7%) and in combination with 0.35 µM GA₃ (0). The highest embryogenic calli were observed in medium with 125 µM 2, 4-D + 5 µM BAP (100%) and the least was in medium with 2, 4-D alone (16.7) and in combination with 0.35 µM GA₃ (0). Multiple shoot induction was observed in medium supplemented with 10 µM kinetin, 10 µM BAP, 0.5 µM GA3, and 200 µM NAA. Maximum shoot elongation (1.667 cm) was in medium containing 10 µM BAP and the least (0.811 cm) was in medium with 5 µM BAP. Rooting was done in Y3 medium containing three levels of indole-3-butyric acid (IBA). The highest response was observed in Y3 medium supplemented with 5 µM IBA+ 0.5 µM GA₃ both with respect to the number of roots 8.33 and root length 5.10 cm while the least was with 10 µM IBA+ 0.5 µM GA₃ with regard to the number of roots 3.33 and root length 2.83 cm. Acclimatization was achieved in media prepared with soil: sand: manure ratio (3:1:1) with 25% survival rate and vermiculate medium with 8.3% survival rate. Hence, in vitro regeneration of coconut through somatic embryogenesis is a viable alternative for mass propagation.

Key words: Cocos nucifera L., somatic embryogenesis, zygotic embryos.