In Vitro Micropropagation of Oca (Oxalis tuberosa Mol.): An Important Plant Genetic Resource from the High Andean Region

Oca (<i>Oxalis tuberosa</i> Mol.) is an Andean crop with high nutritional and cultural value; however, its vegetative propagation makes it challenging to ensure a continuous supply of high-quality planting material. In this study, an efficient and reproducible in vitro propagation protocol was established for the oca genotype OT-001 (Amazonas, Peru), integrating shoot multiplication, rooting, and acclimatization. One-centimeter nodal segments were cultured in MS medium supplemented with 6-benzylaminopurine (BAP) or kinetin (KIN) at increasing concentrations ranging from 0.1 to 2.0 mg L^-1. For rooting, one-centimeter shoots were transferred to MS medium supplemented with indole-3-butyric acid (IBA) or 1-naphthaleneacetic acid (NAA) at increasing concentrations ranging from 0.1 to 2.0 mg L^-1. The variables evaluated four weeks after treatment initiation were regeneration percentage, rooting percentage, number of shoots per explant, number of roots per explant, number of nodes, and shoot length. The regeneration rate reached 100% with both BAP and KIN treatments; however, shoot proliferation was highest with 1.0 mg L^-1 BAP, producing an average of 7.4 shoots per explant compared to 2.3 shoots in the control. Meanwhile, KIN concentrations of 0.2-0.5 mg L^-1 promoted the development of longer shoots (up to 31.4 mm). In rooting, although the control achieved 93.3%, auxin supplementation improved root architecture. IBA at 0.1 mg L^-1 achieved 100% rooting with the longest roots (23.9 mm), while 2.0 mg L^-1 IBA maximized the number of roots (14.2 roots per explant). With NAA, the root systems were dense but shorter. The in vitro-regenerated plantlets exhibited 100% survival after 15 and 30 days of acclimatization in sterile agricultural soil, demonstrating the high quality of the plant material obtained. The protocol enables the production of homogeneous and vigorous plantlets throughout the year and provides a practical foundation for the ex situ conservation of oca germplasm and its commercial propagation. It also establishes the basis for advanced applications such as genetic transformation and gene editing.