Meta-topolin mediated enhanced in vitro propagation and genetic integrity assessment in sweet potato (Ipomoea batatas (L.) Lam)

An improved in vitro propagation protocol by use of meta-Topolin (mT) hormone was developed in sweet potato (Ipomoea batatas (L.) Lam) using nodal explants derived from 12 weeks old in vitro plantlets of different sweet potato accessions. This is the first study that analyzes the effect of meta-Topolin (mT) hormone on sweet potato micropropagation. Enhanced in vitro multiplication was achieved on Murashige and Skoog (MS) medium supplemented with 0.54 mu M 1-Naphthaleneacetic acid (NAA), 0.09 mu M Gibberellic acid (GA(3)) and varying concentrations of mT. A hundred percent shoot induction was obtained on mT concentrations ranging from 3.11 16.58 mu M (except 4.15 mu M). The best multiplication response with maximum number of shoots (7.26 +/- 0.17) and axillary nodes (65.25 +/- 1.81) was achieved on MS medium containing 8.29 mu M mT with an average shoot length of 2.79 +/- 0.27 cm. Shoots multiplied on mT containing medium gave 100% rooting with the best response (9.75 +/- 1.21 roots per explant) recorded on MS medium supplemented with 0.49 mu M Indole-3-butyric acid (IBA). Profuse rooting with multiple secondary roots was observed on this medium. Rooted plantlets were successfully acclimatized and hardened with a survival percentage of 90.48 +/- 0.38%. The effect of different concentrations of mT (low, best and high) on the genetic integrity of regenerated plantlets was tested using 48 ISSR primers. All the successful primers (32) yield monomorphic bands in mother as well as tested plants, thereby confirming the uniformity and genetic integrity of regenerated sweet potato plants. The optimized protocol may be used for large-scale production of true-to-type quality planting material of sweet potato. (C) 2023 SAAB. Published by Elsevier B.V. All rights reserved.