Callogenesis of coconut (Cocos nucifera L.) using immature inflorescence and young leaf explants

The study was aimed at generating callus from immature inflorescence and young leaf explants of coconut (Cocos nucifera L). Eeuwen’s medium which was supplemented with Murashige and Skoog macro salts, 6-Benzylamino purine (BAP) and 6-y dimethylally amino purine (2iP) at concentration of 1 mg/l each, was used as the culture medium. The effect of different concentrations of growth regulators when added to the culture medium was tested on callus generation. The auxins used were 2,4-Dichlorophenoxy acetic acid (2,4-D) and Naphthalene acetic acid  (NAA), at concentrations of 0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55 and 60 mg/l. The immature inflorescence and young leaf explants were used for culture initiation. Callus production was observed between 14 – 26 weeks after culture initiation. The results obtained showed that callus generation was not possible from both explants when concentrations between 0 - 40 mg/l, 2,4-D and NAA were used for media supplementation. The growth regulator that was more effective in generating callus from both leaf and inflorescence explants was 2,4-D, with optimal concentration of 50 mg/l. In leaf culture, the optimal concentration of 2,4-D yielded 40 % callusing explant and 0.082 g fresh mean 
weight of callus, while the inflorescences yielded 20 % callusing explant. By a way of comparison, the leaf explant is to be preferred over the inflorescence explants for callus production in coconut.