Sterilized seeds were cultured on a basal callus induction medium consisting of MS salts (Murashige and Skoog, 1962) and B5 vitamins (Gamborg et al., 1968) fortified with 2,4-D (1– 4 mg L 1) and NAA (0–4 mg L 1) either alone or in combination,30 g L 1 sucrose, 0.5 g L 1 casein hydrolysate and 0.4% (w/v) gelrite.