Effect of auxins and cytokinins on efficient plant regeneration and multiple-shoot formation from cotyledons and cotyledonary-node expiants of groundnut (Arachis hypogaea L.) by in vitro culture technology

Abstract

Tissue cultures were established from cotyledon and cotyledonarynode segments ofArachis hypogaea L. on Murashige and Skoog (MS) medium supplemented with different concentrations of auxins (IAA, NAA, IBA, and 2, 4-D) and cytokinins (KIN and BAP). For callus initiation, high concentration of auxins and low concentration of cytokinins were used, whereas high concentration of cytokinins and low concentration of auxins were used for shoot-bud differentiation. Callus induction and shoot-bud regeneration frequency, however, varied with genotype, expiant, and the different plant-growth regulators combination in the medium. The shoot-bud multiplication was also influenced by genotype, explant type, and growth regulators. The combination of BAP and NAA produced more shoots than other combinations. The maximum number of shoots was obtained from cotyledonary-node segments on a medium containing BAP (5.0 mg/L) and IBA (1.0 mg/L). Rooting of regenerated shoots was achieved on a medium augmented with NAA or IBA (2.0 mg/L) in combination with KIN (0.5 mg/L). Rooted plantlets were successfully established in the soil, where 95% of them survived.

Tissue-culture studies of these expiants suggests the shoots to be ofde nova origin, which would make the system suitable for gene-transfer technology.