The Evaluation of the Water Consumption and the Productive Parameters of a Table Grapevine, Cardinal Cultivar, Grafted onto Two Rootstocks

This trial was carried out over two years in southern Italy. Two grapevine rootstocks, 110R and SO4, were compared to evaluate their ability to extract water from the soil and the effect on the yield and quality of the Cardinal grapevine table cultivar. Therefore, a new approach to plant water consumption based on sap flow was adopted. The earlier and faster water refilling of the xylem in Cardinal onto 110R (C/110R) appears responsible for the earlier evolution of the phenological phases than Cardinal onto SO4 (C/SO4). The maximum length of the principal shoot was reached in Cardinal/110R compared to the C/SO4, while a higher number of lateral shoots with lower internode changed the canopy architecture and light distribution in the C/SO4. The 110R used more water compared to the SO4. It was possible to quantify the real transpired flux of the plant per day: the sap flow was 12.3 L.plant −1 .d −1 and 11.7 L.plant −1 .d −1 in C/110R in the first and second year, respectively, while it was 14% lower in the alternative graft combination. The overall lower C/SO4 water status does not compromise the production result, with similar or higher-quality aspects compared to the alternative graft combination C/110R, which can be also attributed to the strong resilience of Cardinal to water deficit.