HIGH-FREQUENCY SOMATIC EMBRYOGENESIS AND EFFICIENT PLANT-REGENERATIONFROM HYPOCOTYL EXPLANTS OF GROUNDNUT (ARACHIS-HYPOGAEA L)

Embryogenic calli were obtained from hypocotyl explants of groundnut ( Arachis hypogaea L.) cultured on a medium containing different concent rations of 2,4-D or NAA in combination with 0.5 mg/l BAP. Type of auxi n, concentration and genotypes influenced somatic embryogenesis, 2,4-D was found to be the best somatic embryo inductor, As the auxin level increased beyond 20 mg/l in induction medium, both per cent as well as number of embryos were decreased, 2,4-D (20 mg/l) was found to be bet ter than NAA for the induction of globular and heart-shaped somatic em bryos. Somatic embryos developed from these calli following transfer t o a medium supplemented with 0.5 mg/l 2,4-D and 2.0 mg/l BAP was found to be best for embryo maturation. The well-formed embryos germinated into plantlets on MS medium supplemented with BAP (0.5-2.0 mg/l) and N AA (0.25 mg/l). The regenerated plants were transferred to soil and gr own to maturity. Hardened plantlets produced normal flowers and set vi able seeds. The ability of this regeneration system to produce embryos exponentially offers potential for development of new gene transfer t echnology and application to synseed technology.