Somatic embryogenesis and plant regeneration in Abelmoschus manihot (L.) Medicus

Plant regeneration through somatic embryogenesis was achieved from callus-culture-derived hypocotyl explants of Abelmoschus manihot. Somatic embryos developed over the surface of embryogenic calli. Callus cultures were initiated from hypocotyl. segments on 1/2 B5 or 1/2 MS medium containing various concentrations of auxins (NAA, 2,4-D) in combination with cytokinins; (BA, KIN). The highest percentage of callus formation was 98.7% on 1/2 B5 medium supplemented with 0.5 mg l(-1) KIN and 2.0 mg l(-1) 2,4-D. Somatic embryogenesis was achieved after transfer of embryogenic calli to 1/2 MS medium containing 3% sucrose. The average number of somatic embryos per callus clump was 23 +/- 2.1 on 1/2 MS medium after 6 weeks of culture. Scanning electron microscope studies were carried out to observe various developmental stages of somatic embryos. About 87% of the somatic embryos developed into plantlets on 1/2 MS medium containing 3% sucrose after 6 weeks of culture.