PRODUCTION OF F₁ HYBRID CUCUMBER (CUCUMIS SATIVA L.) CULTIVARS VIA SOMATIC EMBRYOGENESIS USING A RITA^® BIOREACTOR

A method for regeneration of complete plants via somatic embryogenesis from callus in a Rita^® bioreactor has been developed in attempt to reduce the cost of F₁ hybrid seed of cucumber. Primary callus was obtained by culturing cotyledon and leaf explants on solid Murashige and Skoog (MS) medium in petri dishes supplemented with different concentrations of auxins and cytokinins while placed in an incubator under continuous light conditions supplied by cool white fluorescent tubes, for twelve weeks or six weeks in darkness. Mature callus was subcultured in an MS growth regulator free liquid medium in Rita^® bioreactors and also in a similar but solid form within petri dishes in a growth room with continuous lighting emitting 42 µmol m^-2 s^-1 supplied by cool white fluorescent tubes and 26±1°C to produce somatic embryos. The germinated somatic embryos in the bioreactors and petri dishes, were detached from the callus and subcultured into Magenta boxes containing MS medium without growth regulators and incubated under similar conditions. Significant differences between the numbers of somatic embryos produced in the Rita^® bioreactor and petri dishes were recorded. However, no significant difference was established in the number of somatic embryos produced following 12 weeks initiation and maturation in light compared with those produced after six weeks initiation and maturation in darkness. There was no significant difference between the numbers of somatic embryos from the explants types (cotyledon and leaf) in bioreactor or petri dishes. A method for regeneration of a complete plant via somatic embryogenesis from callus in a Rita^® bioreactor has been developed.