Agronomic and Physiological Responses of ‘Chardonnay’ Grapevines to Management Strategies with Late Pruning and Late Cane Tying

Abstract

To mitigate the potential drawbacks of late pruning, this study evaluated an alternative approach utilising the anatomical features of the umbrella trellis system, cane pruning, and apical dominance. Vine canes were tied at four distinct phenological stages: before budburst, at the 3-leaf, 5-leaf, and 7-leaf stages (BBCH 00, 13, 15, and 17, respectively). We hypothesised that exploiting apical dominance would allow distal buds to burst first; subsequent arching and tying of the cane would then trigger the burst of the remaining basal buds with a temporal delay. The effects of these treatments were evaluated based on leaf area index (LAI), canopy porosity and structure, fertility coefficients, and yield components, supplemented by must composition analysis at harvest and compared alongside a traditional late-pruned cordon-system evaluated under identical phenological timings. Our findings indicated that delayed tying treatments on umbrella-trained vines did not affect canopy structure, resulted in higher yields, greater average bunch weights, without inducing the negative side effects reported for late pruning cordon-trained vines. Regarding final must composition, the treatments produced minor and inconsistent variations, with no significant differences across most measured parameters at harvest.