In Vitro Propagation of Chinese Potato (Plectranthus rotundifolius (Poir.) J.K. Morton) Through Axillary Shoot Bud Culture

Abstract

An efficient and cost effective in vitro plant regeneration protocol through single nodal segment culture  was achieved in the minor tropical tuber crop, Chinese potato (Plectranthus rotundifolius (Poir) J.K.  Morton), through axillary shoot bud proliferation in Murashige and Skooge medium augmented with  varying concentrations of 6-benzylaminopurine (BAP) and Kinetin (0.5.2.0 mg l-1). BAP at 1 mg l-1  was the most effective medium for multiple shoot induction, which gave an average of 38 shoots/  node, followed by Kinetin (0.5 mg l-1) inducing 22 shoots/node as compared to the other concentrations  of hormones and MS basal medium alone, after 45 days of culture. MS basal medium, though notpromoting shoot multiplication, gave higher shoot length with elongated internodes. In vitro multiplied  shoots transferred to MS medium with 0.5 mg l-1 IBA was optimum for healthy rooting. Rooting of the  micro shoots also occurred in the Kinetin containing shoot multiplication medium itself from the baseand nodes on ageing of the cultures after 85 days of culture. The healthy and vigorous in vitro  regenerated micro shoots were separated out and were hardened upon transfer to plastic cups with  sterile soil and sand. These were successfully acclimatized ex vitro in pots with potting mixture under  green house conditions for four weeks. The survival rate was 90% and the plants that established in  the green house resembled the mother plants in habitat without any morphological variations. This  very simple and efficient protocol can be used to mass propagate elite stable clones of this very  important aromatic tropical minor tuberous vegetable.