Irrigated viticulture expanded fast in Southern European countries to optimize yield and quality and to promote vine longevity. However, intensive irrigation practices increase pressure over the already scarce water resources. In addition, row crops such as grapevine, are more vulnerable to heat stress due to the effects of soil heat fluxes which can influence canopy and berry thermal condition. Therefore, a better understanding of grapevine responses (diurnal and seasonal) to environmental factors (air temperature, VPD, soil water) and agronomic practices (deficit irrigation, soil management) are still required. Ground based thermography was used to monitor canopy and soil temperature patterns along the day and season as a tool to assess vine water status and predict risks of heat stress damage. In the frame of the EU-INNOVINE project, field trials were carried in 2014 and 2015 in South Portugal. We examined the diurnal and seasonal response of two V. vinifera varieties Aragonez (syn. Tempranillo) and Touriga Nacional subjected to sustained deficit irrigation (SDI), and regulated deficit irrigation (RDI, about 50% of the SDI). Diurnal canopy (TC), and soil surface (Tsoil) temperatures were assessed by thermography. Punctual measurements of leaf temperature with thermal couples, leaf water potential and leaf gas exchange were also done. TC values were above the optimal temperature for leaf photosynthesis during the day light period (11-14h to 17h), especially under high VPD and high Tair conditions and in RDI vines. Tsoil was on average about 10-15ºC higher than TC. We found good correlation between TC retrieved by thermography and eco-physiological parameters in both years. In turn, the good correlation between TC and thermal couple temperature data supported robustness of the thermal imaging approach

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