DIRECT SOMATIC EMBRYOGENESIS IN A SELECTED TEA CLONE, TRI-2025 (CAMELLIA-SINENSIS (L.) KUNTZE,O.) FROM NODAL EXPLANTS

An efficient method for the in vitro propagation of a tea (Camellia si nensis (L) O. Kuntze) clone, 'TRI-2025', from somatic embryos is descr ibed. This technique involves two phases; the induction of adventitiou s buds from nodal cuttings followed by the development of somatic embr yos. Single nodal cuttings were excised from 1-year-old in vitro axeni c cultures and inoculated on MS medium with different combinations of IBA/BAP/GA(3). Induction of multiple shoots from nodal explants occurr ed on MS medium with 0.5 mg l(-1) BAP, 0.1 mg l(-1) IBA and 0.0 mg l(- 1) GA, within 6 weeks of incubation. The cultures with multiple shoots were transferred to fresh medium, incubated for 120 days and transfer red to MS medium with half-strength macro nutrients, full-strength mic ronutrients and vitamins and no growth regulator. The direct induction of somatic embryos without callus formation occurred on this medium a t 60% frequency within 4 weeks. The production of embryos continued up on transfer of the cultures to fresh medium and a four- to eightfold m ultiplication rate was obtained during each 6-week culture cycle. The plantlets from these embryos were acclimatised with a 90% success rate . All plants were vigorous and hardy, with well-developed tap-root sys tems.