J. Bhattacharya and S.S. Khuspe
Plant Tissue Culture Division, National Chemical Laboratory, Pune - 411 008, India.
Abstract: A protocol for high frequency somatic embryogenesis in C. papaya was developed using immature zygotic embryo explant of cultivars Honey Dew and CO 2. Somatic embryos were induced in immature embryos, cultured on Murashige and Skoog's (MS) basal medium supplemented with 3 mg/litre of 2,4,5-T, and incubated in the dark for a period of 3-6 weeks. Loosely attached globular somatic embryos appeared from apical domes within 3-6 weeks of incubation. The development of somatic embryos was asynchronous, which passed through globular, heart, and torpedo shape stages. Embryos continued to proliferate with regular subculture and remained morphologically competent for up to one year. Maturation of the embryos was achieved in medium supplemented with ABA [abscisic acid] (0.1 mg/litre). The cotyledonary stage embryos germinated (71.33% in Honey Dew and 59.33% in CO 2) on phytohormone free MS basal medium. Regenerated plantlets were established in the greenhouse and hardened plants were transferred in soil.
