Abstract

To face the challenges induces by the climate change a better water use in agriculture is needed. One of the ways to get it is the genetic selection and breeding programs of genotypes focused on their water use efficiency (WUE). Grapevine crop is commonly growing under water stress conditions; to improve their WUE is a general goal for viticulture. In this study, we show the variability in WUE among clones of Tempranillo, cvar, grown under both pot and field conditions, all submitted to a large range of water availability, and along three consecutive years. Leaf net photosynthesis rate (A(n)), stomatal conductance (g(s)) were measured, and intrinsic water use efficiency (WUEi) was computed as the ratio A(n)/g(s). Firstly, we observed that the WUEi showed important variations among clones. Field-growing plants consistently showed higher WUEi than pot growing ones, and an important year effect was observed. The differences among genotypes were significant in pot conditions, but not in field. Nevertheless, the present results show intra-cultivar variability in Tempranillo in WUEi, and therefore the possibility to build a selection program based in this criterion.