Effects of coconut water on callus initiation and plant regeneration potentials of sweetpotato.

Abstract

Embryogenic callus initiation and plant regeneration in sweetpotato in vitro have been accomplished through various amendments with supplements. Such amendments include use of appropriate growth regulator combinations or inclusion of other supplements that have the potentials to enhance callus initiation and shoot proliferation. Coconut water has been reported to enhance callus induction, shoot development and multiplication in tissue culture of plants but has never been tried in sweetpotato, which is still recalcitrant to most in vitro treatments reported. The objective of this study was to evaluate callus initiation; shoot proliferation and plant regeneration potentials of four different quantities of coconut water levels (0mlL-1, 25mlL-1, 50mlL-1, 75mlL-1 and 100mlL-1) on three sweetpotato cultivars of Papua New Guinea in vitro, on a modified Murashidge and Skoog (MS) medium. The modified medium was supplemented with 3mgL-1 2, 4-dichlorophenoxyacetic acid and 0.5mgL-1 6-benzyl amino purine. The control medium was set without any of the coconut water levels. At coconut water levels lower than 75mlL-, callus initiation and plant regeneration potentials of all the sweetpotato cultivars were relatively low. At coconut water levels of 75mlL-1or higher, more than 85% of SK010, 75% of WHCH005 and 50% of PRAP496 initiated callus that were capable of proliferating into shoots. Shoot proliferation was also poor at lower coconut water levels. Shoot isolates that proliferated from calli at higher coconut water levels were able to grow to maturity.