Optimisation of In vitro Establishment and Medium-term Conservation of Sweet Potato (Ipomoea batatas (L.) Lam.) Varieties from Côte d’Ivoire

Abstract

Aims: The study aims to optimise an integrated protocol for the in vitro establishment, micropropagation, and medium-term conservation of two sweet potato (Ipomoea batatas (L.) Lam.) varieties (PRCO and PBCB) cultivated in Côte d’Ivoire by evaluating disinfection procedures, mineral salt concentrations, and agar levels. Study Design: The Experimental study was conducted under controlled in vitro culture conditions using a completely randomised design. Place and Duration of Study: This study was conducted at the Laboratory of Biology and Improvement of Plant Production, Nangui Abrogoua University, Abidjan, Côte d’Ivoire, from March 2023 to December 2025. Methodology: Two sweet potato varieties (PRCO and PBCB) were used to develop an integrated protocol for in vitro establishment and medium-term conservation. During culture initiation, the effects of disinfectant type, concentration, and exposure time were assessed to identify the most effective sterilisation treatment. For conservation, reduced-strength LS and MS0 media and different agar concentrations were tested to restrict growth while maintaining plantlet viability. Growth, rooting ability, and survival rate were monitored throughout the conservation period. The acclimatisation capacity of conserved plantlets was subsequently evaluated under ex vitro conditions. Results: A significant interaction between genotype and disinfection treatment was observed, indicating that sterilisation efficiency varied according to the variety. Reduced-strength media (LS 50% and MS0 50%) effectively limited vegetative growth while maintaining high viability, with survival rates exceeding 90% during conservation. Among the agar concentrations tested, 6 g L⁻¹ provided the best balance between growth reduction, rooting capacity, and physiological stability. Plantlets maintained under these optimised conditions showed satisfactory rooting and acclimatisation after transfer to ex vitro conditions. Survival rates varied from 60.0 to 88.9 %, although no significant differences were detected between varieties. Conclusion: Optimised disinfection procedures combined with reduced mineral salt concentrations and an appropriate agar level provide an efficient strategy for the medium-term in vitro conservation of sweet potato germplasm. This protocol supports the production of healthy planting material and the sustainable conservation of sweet potato genetic resources in Côte d’Ivoire.