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

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