Micropropagation of banana is limited as explants are difficult to maintain in culture. The present study was conducted to investigate different factors for banana cryopreservation. This study has two parts. In the first part of study in vitro propagation of banana was done to propagate large number of explants for cryopreservation. Whereas, in the second part, banana shoot tips were cryopreserved by vitrification technique. During this study, different parameters such as exposure to plant vitrification solution PVS2 and PVS3, rewarming time were optimized. For cryopreservation by vitrification method, shoot tips were precultured on solidified MS medium supplemented with 0.3 M sucrose for 16 h at 25C. Then they were loaded in loading solution containing 2M glycerol and 0.4 M sucrose for 30 minutes at room temperature. After loading step, shoot tips were dehydrated with plant vitrification solution (PVS2) and (PVS3) with different exposure times (10,30,40,60,90,120 min) respectively. The best result was obtained with shoot tips treated with PVS2 for 60 min and 120 minutes for PVS3 with survival rates of cryopreserved shoot tips as 85% and 33% respectively. Furthermore, effect of different rewarming times was also investigated on shoot tip viability. Among tested different rewarming times (0,2,4 and 6min), 2 min of rewarming time in PVS2 and 4 min of rewarming time in PVS3 were found suitable for cryopreservation as they retained survival rate as 97% and 75% respectively.

The present investigation is focused on the effect of different concentrations of sodium alginate and calcium chloride treatment on banana shoot tip (G-9) encapsulation for the formation of artificial seeds. For this, different concentrations of sodium alginate and calcium chloride were checked for optimum encapsulation. In vitro culture shoot tips of bananas were encapsulated by using different concentrations of sodium alginate i.e. (1%, 2%, 3% and 4%) and calcium chloride (50 mM, 75mM, 100 mM and 150 mM). Further, the storage viability of encapsulated shoot tips was also examined. Encapsulated shoot tips were stored at two different temperatures i.e., 4℃ and 25℃. Results indicated that the best alginate concentration for encapsulation was found at 3% (w/v) and 100 mM calcium chloride. The beads were formed globular, firm and found suitable for handling and exhibited a germination frequency of 93.33% on Murashige and Skoog medium supplemented with BAP and IAA (5.0 + 1.0 mg/l, respectively). The encapsulated shoot tips showed different responses after storage at different temperatures. The multiplication frequency declined for both tested storage temperatures i.e., 4℃ and 25℃. Encapsulated shoot tips stored at 4℃ showed survival for longer storage with a regeneration frequency of 91.33%, whereas, capsules stored at 25℃ resulted in rapid deterioration within 90 days and exhibited a maximum multiplication frequency as 61.66%. This indicates that storage at low temperatures is more effective. This study could be applied as an alternative method of banana micropropagation as well as germplasm conservation.