Balearic varieties of grapevine: study of genetic variability in the response to water stress

The photosynthetic characteristics of twenty varieties of grapevine (Vitis vinifera L.) from Mallorca (Balearic Islands, Spain) and two widespread varieties, Cabernet Sauvignon and Chardonnay were studied under irrigation as well as in response to drought. Despite of the common origin of these cultivars, high variability was found for several photosynthetic characteristics under irrigation.
Interestingly, these variations were significant in gas-exchange parameters (net CO2 assimilation, stomatal conductance and intrinsic water use efficiency). Some varieties presented high carbon assimilation at high water loses’ expense, whereas others were water-saving even under irrigation, which was accompanied by low CO2 assimilation. Escursach was found to be an interesting variety, presenting high carbon assimilation at time with low water consume.These varieties also showed different responses to drought, which allowed to classify them in two main groups: “alarmist” varieties, which showed strong reductions of stomatal conductance in response to relatively low decreases of leaf water potential, and “luxurious” water consume varieties, showing low reductions of stomatal conductance under water stress.