Somatic Organogenesis and Plant Regeneration in Castor (Ricinus communis L.)

An in vitro propagation system developed for castor-bean (Ricinus communis L.) through hypocotyl derived callus cultures. Seeds were surface sterilized with 5 per cent bavistin for 30 min followed by 0.01 per cent HgCl₂ for 4 min to obtain in vitro seedlings germinated with growth regulator free MS medium. The impacts of different concentrations of auxins and cytokinins were evaluated for callus induction, shoot proliferation and ischolar_main induction. Hypocotyls were excised from 10-12 days old in vitro seedlings and were cultured on Murashige and Skoog's (MS) medium supplemented with different concentration of BA, KIN and 2IP. White compact, nodular organogenic callus was obtained on the MS medium fortified with B₅ vitamins and 1.0 mg/l BA (80.84%) or 2.0 mg/l BA(80.17%). Shoot induction from the callus cultures was achieved on MS medium with 0.5 mg/ l KIN + 0.25mg/l BAP (75.00%). Use of 0.2 mg/l GA₃ in combination with 0.5 mg/l KIN and 0.25 mg/l BAP induced maximum number of shoots per explants (7.00) as well as shoot length (6.49cm). For ischolar_main induction, in vitro shoots were transferred to ischolar_maining media containing IAA, IBA and AgNO₃ singly or in combinations but ischolar_main induction was not achieved even after 30 days of culture.