Control of Endogenous Bacterial Contamination and Micropropagation of a Traditional Table Banana (Musa spp. cv. Kanthali) of Bangladesh

Abstract:

Shoot tips of a traditional table banana (Musa spp. cv. Kanthali) of Bangladesh were evaluated for in vitro propagation. Initial surface sterilization (with 0.1% HgCl₂ for 12 minutes) of shoot tips was successful but microbial contamination (mostly bacteria) at the rhizomatous base of the explants was observed within 6～15 days after inoculation which eventually killed 85% of inoculated explants. So, for contamination free culture establishment explants were soaked in two broad spectrum antibiotics namely ampicillin and gentamicin. Cent percent contamination free cultures were established by soaking the explants in 400mg/L ampicillin or 200mg/L gentamicin for 1h. Antibiotic treated explants were found to be full contamination free but failed to regenerate after 3 weeks of culture. But some of them absorbed media for up to 2^nd subculture and showed swelling of explants and some color changes from pale white to light/deep green. Finally, a few days after 3^rd subculture, no growth of explants was observed and all treated explants eventually started to die. Among the untreated alive explants the best medium for single shoot development was MS+4.0mg/L BA+0.5mg/L KT+15% CW and average time required for shoot development was 18～21 days. But the regeneration percentage was very low (30%). The best medium for shoot multiplication was MS+4.0mg/L BA+2.0mg/L IAA+15% CW and only average 3～4 shoots were formed per shoot. Finally, in vitro proliferated shoots produced roots with maximum frequency (90%) in half strength of MS medium fortified with 0.5mg/L IBA.