AN EFFICIENT IN VITRO ESTABLISHMENT AND PLANT REGENERATION FOR CARICA PAPAYA 'MARADOL'

The objective of this work was to develop an efficient in vitro establishment and plant regeneration for Carica papaya ‘Maradol’. Shoot tips and lateral buds collected from 45-days-old non-aseptic seedlings were cultured on Murashige and Skoog (MS) medium. The roles of antibiotics (ampicillin, chloranphenicol and trimetoprim-sulphamethoxazole), and silver tiosulphate (STS) were investigated to obtain bacterial free explants and high tissue viability. Among the antibiotics supplemented to MS, the trimetoprim-sulphamethoxazole was the most effective to inhibit the endophytic bacteria contamination. Several growth regulators were also investigated for callus induction, shoot proliferation and somatic embryos forma¬tion. Callus was induced on MS added with 0.5 mg/L naphthalene acetic acid (NAA), and 0.5 mg/L benzyladenine (BA). The highest efficiency of shoot proliferation was observed in 0.1 mg/L NAA and 0.1 mg/L BA. These media were added with 1.0 µM STS. The somatic embryos were formed in MS with 0.4 mg/L glutamine, 10 mg/L 2,4-dichlorophenoxyacetic acid (2,4-D). The best condition for rooting was half-strength MS medium supplemented with 0.1 mg/L of indole-3-butyric acid (IBA). The best survival of plantlets (90%) was obtained in the potting mix, peat moss:agrolite (1:1, v/v). All plantlets grew and exhibited normal development.