Potato plants are often subjected to heat stress during growth and development, resulting in loss of yield and quality. However, the possibility exists that commercially important genotypes show tolerance to heat stress. In this study, we aim to investigate the morphological and physiological effects of moderate conditions of heat stress on tuberization in nine potato genotypes, and how it affects propagation using an ex vitro and in vitro system. The plant material came from the In Vitro Germplasm Bank of the International Potato Center (CIP). The incubation temperatures of the cultures in in vitro and ex vitro conditions were the ambient in the laboratory and greenhouse, respectively. In in vitro system a randomized complete block design was employed in nine genotypes, two treatments: multiplication culture medium and the same culture medium supplemented with 8.0% sucrose and 500 mg/L-...