Growth and physiology of fourVitis viniferaL. cv. Tempranillo clones under future warming and water deficit regimes

Background and Aims The interactive effects of simulated 2100 environmental conditions (air temperature and CO2 level) and water deficit (WD) on four clones of Vitis vinifera cv. Tempranillo were investigated. Methods and Results Fruit-bearing cuttings were subjected to: (i) two temperature/CO2/relative humidity (RH) regimes: climate change (28°C/18°C, 700 μmol/mol CO2 and 33%/53% RH, day/night) versus current climatic conditions (24°C/14°C, 400 μmol/mol CO2 and 45%/65% RH), combined with (ii) two water availabilities: well-watered (WW) versus WD. Climate change increased net photosynthesis (An), transiently ameliorating the low carbon fixation rates under drought, but not the reduction in vegetative and reproductive growth. Climate change increased intrinsic water use efficiency (An/gs), especially when combined with WD, but not the instantaneous water use efficiency (An/T). The clones exhibited differences in the ripening time, plant vigour and reproductive growth. Variability in the response of An, phenology and growth to the simulated conditions was observed among clones. Conclusions Differences in the length of the reproductive cycle conditioned, in part, the physiological response of the clones to the environmental factors. Significance of the Study The study improves our understanding of the interactive effects of climate change factors and provides insights into the response of different clones, as the basis for the adaptation of cultivars in their traditional growing regions.