Direct Somatic Embryogenesis and Organogenesis from Axillary Meristem in Taro ( Colocasia esculenta var. esculenta)

Abstract

This is a first report on direct somatic embryogenesis and organogenesis of taro (Colocasia esculenta var. esculenta) using axillary meristem explants. Best somatic embryogenesis was observed in cultures that were established on Murashige and Skoog (1962) (MS medium) containing 10 µM 2, 4-dichlorophenoxyacetic acid (2, 4-D) and 2 µM thidiazuron (TDZ) and then transferred on medium with 5 µM TDZ. MS medium containing 3 μM gibberellic acid (GA) and 4.5% sucrose proved best for inducing germination in somatic embryos which converted into 20.0 ± 3.46 complete plantlets per embryo cluster per explant on ½ strength MS basal salts with 1% sucrose. Best organogenesis was observed in cultures that were established on MS medium containing 2 µM TDZ and then transferred on medium with 5 µM TDZ. Subsequent transfer of these cultures on MS medium with 5 µM indole-3-acetic acid (IAA) and 7.5 µM 6-benzylaminopurine (BAP) resulted in maximum shoot multiplication. MS medium containing 2 µM IAA proved best for inducing rooting in multiplied shoots. Both direct somatic embryogenesis and organogenesis resulted in mass and rapid production of taro plantlets which were acclimatized and field transferred. Vigorous plant growth and healthy corm production was observed in the field. This in vitro propagation method of taro through direct somatic embryogenesis and organogenesis is significantly reliable over prevailing methods available for other cultivars and provides sustainable means of quality taro production in the Pacific and the Caribbean region where non-availability of elite seedlings is a limiting issue.