Multiple Shoot Regeneration from Immature Embryo Explants of Papaya

A simple and rapid method for multiple shoot formation in vitro from immature embryo axis explants of Carica papaya L. cvs. Honey Dew, Washington and Co2 is described. Multiple shoot regeneration was achieved by culture of the explants on modified Murashige and Skoog (MS) medium supplemented either with thidiazuron (TDZ; 0.45-22.7 μM) or a combination of benzylaminopurine (BAP; 0.2 - 8.84 μM) and naphthalene acetic acid (NAA; 0.5 - 2.64 μM). Highest frequency of shoot regeneration occurred on medium supplemented either with 2.25 μM TDZ or a combination of BAP (4.4 μM) and NAA (0.5 μM). Composition of the basal media influenced the frequency of multiple shoot initiation. Stunted shoots regenerated at 4.5 μM and higher concentrations of TDZ. Such shoots could, however, be elongated by transfer to medium containing 5.7 μM GA3. Rooting of the regenerated shoots was achieved in presence of indolebutyric acid (IBA; 4.92 - 19.68 μM), however, least response was in presence of 14.7 μM IBA. Rooted plants were hardened and transferred to pots.