The objectives of this study were to compare some physiological indices related to winter cold tolerance of two field-grown grapevine (Vitis vinifera L.) cultivars under different training systems. This experiment was conducted over two consecutive years (2020 and 2021) in a factorial arrangement based on a randomized block design, with three sampling dates, i.e., December, January, and February, for each year. The treatments included two factors: (1) four training systems (one non-trellis or creeping system (C) and three bilateral cordon trellis systems: I-shape, T-shape, and Y-shape), and (2) two grape cultivars (‘Khalili’ and ‘Perlette’). In all three sampling phases across both years, bud malondialdehyde (MDA), hydrogen peroxide (H2O2), and water content (WC) were higher in the ‘Perlette’ cultivar under the creeping training system compared to the cordon trellis systems. However, the ‘Khalili’ cultivar under the Y-shape bilateral cordon training system had higher proline, soluble sugar, polyamine, and abscisic acid content in all three sampling stages compared to other treatments. In both years, the content of these compounds was lower in the ‘Perlette’ cultivar under the creeping training system compared to the bilateral cordon trellis systems in all three sampling stages. According to the results, the cordon training systems increased the cold tolerance of both cultivars compared to the creeping system, with the Y-shape cordon training system inducing greater cold tolerance in the vines compared to the T-shape and I-shape training systems.
