Development and optimization of in vitro shoot regeneration in Physalis peruviana using cotyledon explants

The genetic improvement of Physalis peruviana L. faces important challenges because it is a recalcitrant species, which limits its use in breeding and conservation programs. In the present research, the objective was to develop an effective regeneration protocol using cotyledon cultures. For this purpose, the effects of zeatin (ZT) and meta-topoline (mT) at concentrations of 0, 0.5, 1.0 and 2.0 mg/L and the effects of several auxins, including indolbutyric acid (IBA), indolacetic acid (IAA), naphthaleneacetic acid (NAA) and 2.4-dichlorophenoxyacetic acid (2.4-D), on morphogenetic responses were evaluated. A maximum regeneration of 62.5 % was achieved with the combination of 2 mg/L ZT, 2 mg/L mT, and 0.5-1 mg/L IBA. For root formation, the best results were obtained with the combination of 2 mg/L ZT, 2 mg/L mT, and 1 mg/L NAA, reaching a maximum rate of 87.5 %. In conclusion, specific combinations of cytokinins and auxins can overcome the resistance of P. peruviana to regeneration and provide a solid basis for biotechnological applications such as genetic transformation and germplasm conservation.