Physiological tools for irrigation scheduling in grapevine (Vitis vinifera L.)

In the present review, current knowledge on grapevine responses to water stress is summarised. Based on this knowledge, the usefulness of different physiological parameters is discussed, and current knowledge on their applicability for water stress detection and irrigation management in grapevines is reviewed. Partial root drying (PRD) and regulated deficit irrigation (RDI) programs are proposed as the most promising tools for such purpose. Among RDI programs, several parameters are proposed as putative indicators of irrigation convenience and dosage. These are sap flow (measured by sap flow meters), trunk growth variations (measured by linear transducers of displacement, LTDs), canopy temperature (assessed by infrared thermometry), reflectance indices (measured by spectroradiometers or specifically designed instruments) and chlorophyll fluorescence (measured by either active or passive fluorometers). Advantages and disadvantages of all these tools are discussed.