Effects of mutagens on somatic embryogenesis and plant regeneration in groundnut

Abstract

The embryogenic calli (EC) were obtained from hypocotyl explants of groundnut (Arachis hypogaea L.) cultured on Murashige and Skoog (MS) medium supplemented with different concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D) in combination with 0.5 mg dm−3 6-benzylaminopurine (BAP). The EC were exposed to γ-radiation (10–50 Gy) or treated with 1–5 mM of ethyl methane sulphonate (EMS) or sodium azide (SA). The mutated EC were subcultured on embryo induction medium containing 20 mg dm−3 2,4-D. Somatic embryos (SE) developed from these calli were transferred to MS medium supplemented with BAP (2.0 mg dm−3) and 0.5 mg dm−3 2,4-D for maturation. The well-developed embryos were cultured on germination medium consisting of MS salts with 2.0 mg dm−3 BAP and 0.25 mg dm−3 naphthaleneacetic acid (NAA). Well-developed plantlets were transferred for hardening and hardened plants produced normal flowers and set viable seeds. The fresh mass of the EC, mean number of SE per explant and regeneration percentage were higher at lower concentrations of mutagens (up to 30 Gy/3 mM). Some abnormalities in regenerated plants were observed, especially variations in leaf shape.