Influence of irrigation on yield and quality of cv. Touriga Franca in the Douro Region

The Douro Region is characterized by a typically Mediterranean climate, with extreme temperatures and irregular rainfall throughout the year. This experimental trial was carried out on a vineyard plot of Touriga Franca, grafted in 110R, at Quinta da Cabreira, property of Quinta do Crasto, S.A., located in the Douro Region. Four irrigation modalities were established, in three blocks, according to the percentage of cultural evapotranspiration (ETc): R 0 , the control, without irrigation; R 25 , irrigated with 25% ETc; R 50 , with 50% ETc and R 75 , with 75% ETc. Irrigation had repercussions on total leaf area, with statistically significant lower value for R 0 and greater for R 75 . Concerning the ecophysiological parameters, the water leaf potential was lower in R 0 than at R 50 and R 75 . On the yield components, it was observed a higher number of clusters in R 75 and a smaller quantity in R 0 and the bunch weight was also affected by the amount of water provided, with the R 50 or R 75 having a higher value. Even if the berry weight has not presented differences, those factors affect yield, that was higher in the R 50 and R 75. Concerning the quality, no significant differences had been found on the various components tested.