Effects of cefotaxime, amino acids and carbon source on somatic embryogenesis and plant regeneration in four Indian genotypes of foxtail millet (Setaria italica L.)

The effects of cefotaxime, amino acids and carbon source on somatic embryogenesis and plant regeneration using mature seeds in four genotypes (‘CO5’, ‘CO7’, ‘TNAU43’ and ‘RS118’) of foxtail millet have been studied. The ‘CO5’ gave a superior response in callus induction, somatic embryogenesis and regeneration. The highest percentage (69.3%) of embryogenic callus induction was obtained in ‘CO5’ on Murashige and Skoog (MS) medium supplemented with 3.5 mg L⁻¹2,4-dichlorophenoxyacetic acid (2,4-D), 1 mg L⁻¹kinetin and 1 mg L⁻¹1-naphthaleneacetic acid (NAA). Somatic embryogenesis and shoot regeneration were influenced by amino acids, carbohydrates and cefotaxime in culture medium. Maximum response of somatic embryo induction and maturation was seen on MS medium containing 3.5 mg L⁻¹2,4-D, 1 mg L⁻¹kinetin and 1 mg L⁻¹NAA, 750 mg L⁻¹proline, 2.0 mg L⁻¹glycine, 150 mg L⁻¹arginine, 800 mg L⁻¹casein enzymatic hydrolyzate, 20 g L⁻¹each sucrose and maltose and 500 mg L⁻¹cefotaxime. The highest frequency of plant regeneration with 21.3 shoots was obtained in ‘CO5’ on MS medium containing 3 mg L⁻¹6-benzylaminopurine, 0.2 mg L⁻¹2,4-D, 750 mg L⁻¹proline, 2.0 mg L⁻¹glycine, 150 mg L⁻¹arginine and 800 mg L⁻¹casein enzymatic hydrolyzate. The highest response of root induction with more roots and longer roots was observed in ‘CO5’ when cultured on half-strength MS medium. The in vitro-regenerated plantlets were carefully transferred to soil cups, maintained in growth chamber for a week, hardened and grown to maturity in the field.