Micropropagation and in vitro germplasm conservation of endangered Musa balbisiana ‘Kluai Hin’ (BBB group)
Multiple shoot formation of edible bananas (Musa balbisiana, BBB group) ‘Kluai Hin’ was achieved through organogenesis in bud culture. Excised apical and lateral buds were cultured on a modified Murashige and Skoog (MS) medium supplemented with 22 μM BA and 15% (v/v) coconut water (CW). For mass multiplication, the proliferated shoots were subcultured to MS media containing several concentrations of BA and TDZ. The highest shoot numbers was 21.2 shoots per explant when subcultured to MS medium supplemented with 44 μM BA. Shoot produced roots within 7 days on MS basal medium without plant growth regulator. Microshoots of ‘Kluai Hin’ were stored in 4 different conditions and on three types of carbon sources (including, sucrose, glucose and sorbitol) at the concentrations of 1, 3 or 5%. Results revealed that sucrose was the suitable carbon source for storing microshoots of ‘Kluai Hin’ at 25°C under a 16 h photoperiod for 6 months. Alginate encapsulation of microshoots for conservation of ‘Kluai Hin’ was established as well. Microshoots excised from multiple shoot cultures were encapsulated in 3% sodium alginate prepared in MS medium and complexed with 50 mM calcium chloride. Maximum conversion frequency of 73% was noted from encapsulated microshoots cultured on MS medium supplemented with 22 μM BA. Plantlets developed from encapsulation were successfully transferred to field conditions and all the resultant plants were shown to be morphologically normal.
Key words: Encapsulation‘Kluai Hin’, micropropagation, Musa balbisiana, slow growth.