Somatic embryogenesis and plant regeneration from immature zygotic embryos of papaya (Carica papaya L.).

Immature zygotic embryos from open-pollinated and selfed Carica papaya L. fruits, 90 to 114 days post-anthesis, produced 2 to 20 somatic embryos on apical domes, cotyledonary nodes, and radicle meristems after culture for three weeks on half-strength Murashige and Skoog (MS) medium supplemented with 0.1 to 25 mg l(-1) 2,4-dichlorophenoxyacetic acid (2,4-D), 400 mg l(-1) glutamine, and 6% sucrose. After six weeks of culture, about 40 to 50% of the zygotic embryos had become embryogenic, and each embryogenic embryo yielded hundreds of somatic embryos within five months of culture on media supplemented with 2,4-D. Somatic embryos matured on half-strength MS medium, germinated on MS medium containing 5 mg l(-1) kinetin, and grew large enough for greenhouse culture on MS medium. Shoots were rooted in vermiculite and grown in the greenhouse.