Regeneration of plants from alginate-encapsulated shoots of Rhododendron dalhousiae Hook. F.

A method has been developed for plant regeneration from alginate-encapsulated nodal segments of Rhododendron dalhousiae. Shoot tips collected from in vitro proliferated shoots were used for synthetic seed production. For encapsulation, nodal segments were mixed with MS medium supplemented with 3% sodium alginate and incubated with calcium chloride (60 mM). The maximum frequency (69%) of conversion of encapsulated shoot tips into plantlets was achieved on MS medium containing 25 ?M 2-isopentenyladenine (2iP) along with additive such as, 100 mg L-l polyvinyl pyrrolidone (PVP), 100 mg L -l ascorbic acid, 10 mg L-l citric acid. The presence of 2iP (25 ?M) with IAA (0.6 ?M) improved re-generation. Amongst the two gelling agents used higher shoot proliferation as well as better growth were observed in cultures grown on Agar in comparison to Phytagel medium. Encapsulated nodal segments stored at 4°C for 25 days also showed successful conversion, followed by development into complete plantlets when returned to regeneration medium. Liquid medium was superior over solid medium for root formation and growth. IBA (1.0 ?M) was more effective than other auxins for root induction. Plantlets with developed shoot and roots were hardened off to survive ex vitro conditions and successfully established in greenhouse. Possibility of direct sowing of synthetic seeds in the soil was also examined