Influence of genotype on in vitro multiplication potential of Arachis hypogaea L

Rapid clonal propagation through in vitro techniques using cotyledonary node as an explant has been attempted in the high yielding, tikka-susceptible (ICG 11337, AK 1224, ICGS 44, JL 24) and tikka-immune (ICG 6284) varieties of Arachis hypogaea L. Cotyledonary nodes were excised from the 12–15 days-old axenic seedlings and cultured in the presence of various concentrations of N6 –benzylaminopurine (BAP) (1, 5, 10, 15, 25 and 50 mg L–1). BAP-free control showed very little or no sign of multiplication in terms of multiple shoot, axillary branch and shoot bud formation. In the presence of higher concentrations of BAP, cultured explants showed the development of multiple shoots, axillary branches and shoot buds. Thus, a tri-directional multiplication pathway (multiple shoot, axillary branch and shoot bud) in a single medium has been achieved in the tested varieties of Arachis hypogaea L. The regeneration of maximum number of shoots, axillary branches and shoot buds from the excised cotyledonary nodes and their corresponding requirements for BAP differed across varieties, which might be due to variation at their genotypic levels. The isolated shoots were quickly rooted in the presence of a-naphthalene acetic acid (NAA) (1 mg L–1) and well-rooted plantlets were successfully transferred to the soil following a standard hardening protocol.