Optimization of IBA for Efficient Survival of Micropropagated Garcinia indica Choisy Shoots Using in-vitro and ex-vitro Rooting Techniques

Aims: The study focuses on optimization of concentration and time of rooting hormone exposure of IBA (Indole-3-Butyric Acid) for efficient survival of tissue culture raised Garcinia indica Choisy plantlets for in-vitro and ex-vitro rooting techniques.

Study Design: The subcultured microshoots of Garcinia indica were subjected to in-vitro and ex-vitro rooting trials by treating them with IBA of varying concentration and time, to standardize these particular parameters required by this auxin to induce rooting.

Place and Duration of Study: Rooting trials were carried out in Plant tissue culture-Biochemical Sciences Division of CSIR- National Chemical Laboratory, Pune 411008 between June 2018 and April 2019.

Methodology: Regularly subcultured five to six years old shoots from female trees of Garcinia indica were used for the study. Various concentrations of IBA in correlation with time were used for in-vitro and ex-vitro root induction. The rooted plantlets were then transferred to polyhouse for acclimatization and will further be planted in open field locations in June 2019.

Results: Induction of rooting was observed within thirty days of treatment with IBA. It was observed that 500ppm of IBA gave 30% rooting for in-vitro rooting trials whereas 2000ppm of IBA induced 80% rooting for shoots given ex-vitro rooting treatments. An interesting phenomenon that was observed for 70% of the shoots which failed to induce rooting by in-vitro treatment was that they survived with 100% rooting success under ex-vitro rooting conditions. The hardened plantlets were successfully acclimatized in the polyhouse with survival rate of 90% and were further transferred to polythene bags with rooting mixtures of sand: farmyard manure: coco peat (1:1:2). These plantlets have been healthy for the last 6 to 9 months and will be transported for field trials in June 2019.

Conclusion: Ex-vitro rooting technique was found to be more effective than in-vitro rooting. Thus, by optimizing the rooting hormone parameters, female plants of Garcinia indica can be successfully grown using tissue culture technology and can be propagated in large numbers to increase the female plant number in plantations.