Direct Somatic Embryogenesis and Plant Regeneration from Plumules of Hot Pepper Seedlings
2009
Han, J.S., Kyungpook National University, Sangju, Republic of Korea | Kim, J.H., Korea University, Seoul, Republic of Korea
A regeneration protocol via direct somatic embryogenesis from the plumules of in vitro-sown seedlings was developed in hot pepper (Capsicum annuum L.). To induce somatic embryogenesis of hot pepper, the effects of various culture conditions and genotypes were evaluated. After mature seeds were directly sown on a modified Murashige and Skoog's medium for pepper (MMSP) supplemented with 2,4-dichlorophenoxyacetic acid (2,4-D), 6-benzylaminopurine (BA), and high sucrose, the germination rate, formation of callus, and somatic embryogenesis were checked. The germinated seedlings of selected MC-12 and CCA323 among tested genotypes were transferred to plant growth regulator (PGR)-free MMSP, and then the frequency of somatic embryogenesis was investigated. The somatic embryogenesis from plumules of hot pepper seedlings was affected by cytokinins in particular genotypes: the frequency of somatic embryogeneis was decreased on the sowing media with more than 1 mgㆍL-¹ BA and the transplanting medium with zeatin. Meanwhile, the partial substitution with D-mannitol for high sucrose did not influence the somatic embyrogeneis. Collectively, the highest rate (38.3%) of somatic embryo induction from plumule was obtained when the seeds of 'MC-12' inbred line were sown on the MMSP with 2 mgㆍL-¹ 2,4-D, 1 mgㆍL-¹ BA, and 80 gㆍL-¹ sucrose at 25℃ with illumination for 16 hours each day, and then transferred into the MMSP with no PGR and 30 gㆍL-¹ sucrose. Isolated somatic embryos germinated into normal plantlets after sub-culturing to PGR-free MMSP. The regenerants were easily acclimatized in a greenhouse and grew into mature plants. Most of the somatic embryo-derived plants were undistinguishable from the wild-type ones by their phenotypes except for only one somaclonal variant. In addition, all of the somatic embryo-derived mature plants normally set the fruits and generated the next progenies. We believe that the present results might be helpful for incorporating into a genetic engineering system in hot pepper.
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