Hydric flows and dynamics of calcium accumulation in table grape berries

A two-year research was carried out in Southern Italy on Vitis vinifera 'Italia' to evaluate the effect of water availability on calcium uptake and accumulation in berries and on fruit quality. Three watering volumes, corresponding to the restitution of 120%, 80% and 40% of water lost by evapotranspiration, were compared. During the growing season, berry development and ripening kinetics were monitored on a weekly basis. In addition, on dried tissue samples (skin, flesh and seeds), calcium concentration was measured. At commercial harvest, the main quantitative and qualitative yield parameters were determined. Water availability significantly influenced calcium accumulation in berry tissues. The highest calcium concentrations were detected in skin and flesh tissues and under well watered treatments. Calcium concentrations in skin and flesh showed an increasing trend up to veraison (69 and 62 days after flowering in 2009 and 2010, respectively), then decreased and reached constant values at the final stages of fruit development. These findings indicate that calcium accumulation in berries may be substantially modified through hydric flows management up to veraison.