The high demand for plant material from Calendula officinalis in the production of herbal medicines and cosmetics, turns the technique of plant-tissue culture into one of the alternatives for the improvement of crops over a short period of time. A protocol for tissue culture was developed from segments of seedlings of C. officinalis, in order to improve the proliferation of shoots and roots. We used a Murashige and Skoog (MS½N) medium, reduced to half the concentrations of NH4NO3 and KNO3 to verify the effect of different types of explants (basal, intermediate, and apical), a medium containing beach sand as support instead of agar, and the effect of auxins and cytokinins (TDZ tidiazuron; BAP, 6-benzylaminopurine, IAA, indol-3-acetic acid, IBA, indol-3-butyric acid, NAA, naphthalene-acetic acid) on plant development in vitro. The results showed pronounced rooting from the apical explants, as well as a greater elongation of shoots and number of leaves. The solid medium was more suitable for the C. officinalis cultures. Shoot proliferation was dependent on cytokinins with better results from the influence of TDZ or BAP compared to the other treatments. Plants regenerated from the medium containing TDZ displayed a glazed appearance and morphogenetic deformations. The highest rate for rooting (80%) was obtained using IAA 0.1mgL-1. Through in-vitro propagation, healthy C. officinalis plants were obtained with roots which can acclimatise, allowing the continuous supplement of raw material.
