Standardisation of in vitro propagation technique in banana

Abstract

Investigations were carried out at the Plant Tissue Culture Laboratory of the College- of Horticulture, Vellanikkara during 1988-90 to standardise the in vitro propagation technique in banana. Three banana cultivars namely Nendran (AAB) , Palayankodan (AAB) and Red banana (AAA) were utilised for the study. For standardising the explant, three types of explants were used namely shoot tip , eye bud and floral apex. For culture establishment, axillary shoot initiation and in vitro rooting studies different types of growth regulators were made use of. They were auxins (NAA, IAA and IBA) , gibberellin (GA) and cytokinins (BA andkinetin) . The plantlets produced _in vitro were subjected to different types of hardening treatments to secure a better establishment of planted out plants For shoot tip and eye bud explants, surface sterilization using mercuric chloride (0.2 per cent) for 5 min. was' found to be the best, but for floral apex ex plant an initial rinsing of the explants with 95 per cent absolute alcohol for 30s followed by mercuric chloride treatment (0.05 per cent) for 10 min. was found to be best. Better and speedier ex plant establishment and growth of shoot tip, eye bud and floral apex explant was observed in MS (semi-solid) medium containing NAA 0.5 ppm and BA 3.0 ppm Gibberellic acid was found to have unfavourable effect on culture establishment and growth. Shoot tips collected during November to April recorded maximum surviva l percentage. Among the physical injury treatments for enhancing the release of axillary buds in culture splitting the apical dome of shoot tip longitudinally into two halves and culturing each half separately was found to be the best. The addition of ascorbic acid into the media at the rate of 50 mg/1 reduced media and ex plant discolouration due to polyphenol oxidation. When the performance of the three explants w.ere compared', floral apex ex plants took more time for culture establishment. The three banana cultivars used for the study responded differently in culture.