REGENERATION OF BABACO (CARICA-PENTAGONA) FROM OVULAR CALLUS

Ovules of babaco [Carica pentagona (Heilborn) Badillo], 23 to 140 days old, were cultured to initiate regenerative callus. Callus developed from the integuments and possibly from the nucellus. Ovules of greater length and age produced more calli on White's medium or medium with half-strength MS salts than on full-strength MS. Ovules > 60 days old that were chilled for 24 hours produced significantly more callus than fresh ovules < 60 days old. Ovular calli of summer and fall fruits (73 to 90 days old) grown at 23 +/- 2C under cool-white fluorescent lamps (16- or 18-hour photoperiod, 12 or 16-mu-mol.s-1.m-2) developed green areas that subsequently produced nodular structures. Nodular structures produced proembryonal structures that developed into mature somatic embryos when transferred to media containing either GA3 (0.1 mg.liter-1) plus activated charcoal (2.0 g.liter-1) or casein hydrolysate (200 mg.liter-1) plus IAA (0.5 mg.liter-1). Somatic embryos converted into plantlets when transferred to embryo conversion medium. Chemical names used: 1-H-indole-3-acetic acid (IAA); gibberellic acid (GA3).