In vitro clonal propagation of dioecious Carica papaya

A procedure for in vitro propagation of dioecious papaya clones is described. A high rate of success in culture estbalishment was obtained when axillary buds were taken from lateral shoots of hedged rooted cuttings grown in a greenhouse. Seasonal endophytic contamination was suppressed by shaking propagules for 24 h in 300 mgl^-1 rifampicin or by incorporating it at 50 mgl^-1 into the medium. Murashige & Skoog (MS) basal medium supplemented with 0.5 mgl^-1 6-benzyladenine and 0.1 mgl^-1 naphthaleneacetic acid was used for establishment and proliferation. The addition of 160 mgl^-1 adenine sulfate improved multiplication and shoot growth. An elongation stage on MS medium supplemented with 1.0 mgl^-1 kinetin and 0.05 mgl^-1 naphthaleneacetic acid was necessary before rooting. Rooting was obtained at a high rate on half-strength macroelements of MS medium supplemented with 1.0 mgl^-1 indole-3-butyric acid. Commercial plots of papaya plants obtained through this procedure already exist.