In vitro regeneration of sweet potato (Ipomoea batatas (L.) Lam.) Convolvulaceae, from leaf and petiole explants

Abstract

Biotic stresses are the major constraints that result in total loss of sweet potato (Ipomoea batatas (L.) Lam.) yield. The establishment of in vitro regeneration protocol for this plant is essential to improve it through tissue culture and genetic engineering. The objective of this study was to establish in vitro regeneration protocol for sweet potato varieties Beletech and Awassa-83 using leaf and petiole explants. MS medium containing different concentrations of 2,4-D and kinetin were used to evaluate their effect on callus induction whereas different concentrations of BAP were used to evaluate its effect on shoot regeneration from callus. BAP alone or in combination with GA3 was used to evaluate their effect on shoot multiplication whereas IBA was evaluated for its effect on rooting. The highest percentage of callus induction (93%) was obtained from petiole explants of both varieties on MS medium containing 0.05 mg/l 2,4-D in combination with 0.5 mg/l kinetin. The highest percentage of shoot regeneration from leaf explants was obtained on growth regulators-free MS medium while the best regeneration from petiole explants was obtained on MS medium supplemented with 1.0 mg/l BAP in both varieties. The highest number of shoots per node (2.40 ± 0.11) was obtained on MS medium containing 1.0 mg/l BAP from shoots originally obtained from callus of leaf explants of Awassa-83. All shoots cultured on MS media containing different concentrations of IBA and the growth regulators-free medium resulted in 100% rooting. After one month of acclimatization, more than 90% of plantlets survived.

Key words/phrases: Callus, Growth regulators, Shoot regeneration, Sweet potato.