RAPID PRODUCTION OF VIRUS-FREE PLANTLETS BY SHOOT TIP CULTURE IN VITRO OF PURPLE-COLOURED SWEET POTATO (IPOMOEA BATATAS (L.) LAM.)

A rapid virus-free seedlings formation protocol was established for purple-coloured sweet potato by shoot tip culture In vitro. The effects of two factors, namely BAP, NAA and their interaction, on callus, roots, buds and rooted plantlets initiation were evaluated by orthogonal design with two factors and four levels. The variance analysis of the experimental results showed that the actions of the two factors and their interaction had significantly different effects on callus, bud, root and rooted plantlet initiation. The best medium for adventitious bud induction was the combination of solid MS supplemented with 1.0 mg l −1 BAP. However, the best medium for rooted plantlet was the combination of solid MS supplemented with 0.5 mg l −1 BAP and 0.2 mg l −1 NAA. Rooted plantlets were acclimatized to greenhouse conditions and appeared normal. The plantlets from shoot tip tissue culture were transplanted successfully. At the same time, the regenerated seedlings were surveyed by the method of indicator plant and enzyme-linked immunosorbent assay on nitrocellulose membranes (NCM-ELISA), and the virus-free plantlets of purple-coloured sweet potato was obtained. In vitro shoot tip culture can be a useful tool in the provision and conservation of virus-free plantlets of purple-coloured sweet potato.