In vitro PROPAGATION OF BANANA SHOOT TIPS AND CRYOPRESERVATION BY VITRIFICATION

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.