Analysis and agrometeorological modelling of grapevine responses to different trellising systems

As the greater part of current viticulture is based on traditional trellising systems, usually in single hedgewall training, the aim of this research is to evaluate the possibility of introducing alternative trellising systems in order to improve canopy architecture and leaf distribution, and optimize light interception. In 2001 and 2002 field measurements (agrometeorological variables, vegetative growth, productivity and physiological behaviour) and modeling were performed on Sangiovese grapevines in a Tuscan vineyard with two trellis systems: a single hedgewall and a low double hedgewall (lyre trellis). The vines were spur pruned and cordon trained and the planting density was 6,667 vines/hectare. The two trellising systems were distributed in a randomized block design with 4 replications of 3 rows each. Data were collected from the central row. The simulation was obtained using a model, implemented with the Stella language, consisting of three sub-modules concerning photosynthesis, respiration and biomass accumulation. Light interception was greater for the lyre system than for the single cordon, while no differences were obtained in single leaf photosynthesis measurements between the trellis systems. Vegetative growth was higher for the lyre, indicating that lyre had a higher whole plant photosynthesis. The lyre system had greater yield due to a higher cluster number and a higher cluster weight compared to the single cordon training. No differences in must sugar content, titratable acidity or anthocyanins were observed. Models satisfactorily simulate the growth of grapevine under the single cordon system, while the growth of the lyre vine was extremely underestimated.