Induction of somatic embryogenesis in cashewnut (Anacardium occidentale L.)

Somatic embryogenesis was induced in callus cultures derived from nucellar tissue of cashewnut (Anacardium occidentale L.). Callus was obtained from n ucellar tissue after 3 wk of culture on semisolid Murashige and Skoog (MS) basal medium supplemented with 2,4-dichlorophenoxyacetic acid (2,4-D, 5 mu M) + gibberellic acid (GA(3), 15 mu M) + N-6-benzyladenine (BA, 5 mu M) Thi s callus gave rise to an embryogenic mass after 9 wk on maintenance medium containing 2, 4-D (10 mu M) + GA(3) (15 mu M) + 4% sucrose + 0.5% activated charcoal + 10% coconut water (CW) + 0.05% casein hydrolysate (CH). The emb ryogenic mass, after transfer to medium supplemented with 2,4-D (5 mu M) GA(3) (30 mu M) + 4% sucrose + 0.5% activated charcoal + 10% CW + 0.05% CH, gave rise to somatic embryos. The developmental stages of somatic embryos were observed using light and stereo microscopes. Histological study of som atic embryo development was also carried out. The present study would be us eful for clonal propagation, and variety improvement in cashewnut, which is essential due to its increasing demand and export potential.