Influence of Water Deficit on Olive Tree (Olea europaea L.) cv. Arbequina during the Winter in an Arid Argentinean Region

ALBERTO IBAÑEZ; CARLOS PARERA; PIERLUIGI PIERANTOZZI; MARIELA TORRES

San Juan

Simposio; VII International Symposium on Olive Growing; 2012

INTA – ISHS – COI – MINCyT – UCCuyo – UNCuyo - UNdeC

The expansion of olive cultivation to new regions with different climate regime to that of the Mediterranean basin highlights the need of studies on how water availability affects the different olive phenological stages, taking in account that its status evergreen allows to perform photosynthesis at any time of year. The aim of this work was to study the influence of water stress during the pre-flowering period (middle June ? early September) on agronomic and physiological parameters in the olive tree (Olea europaea L.) cv. Arbequina in an arid argentinean area (San Juan province). In winter season, the effect of two deficit irrigation levels equivalent to 50 and 0% of evapotranspiration crop (T1 and T2, respectively) was analyzed comparing these with a control treatment without water stress (100% ETc, T3). After 15 d, both soil volumetric water content (SVWC) and leaf water potential (PHL) were substantially lower in the unirrigated treatment (T2 vs T1 and T3). These differences in PHL and SVWC were consistent through to the end of the experiment in treatments with water deprivation (PHT: -7.7, -4.5 and -2.4 MPa in T2, T1 and T3 respectively; SVWC: 4.97, 10.95, 15.51% in T2, T1 and T3 respectively). A reduction in leaf gas exchange parameters, including leaf conductance (gs), was also observed 15 d after water deprivation in olives trees growing under non-irrigated condition and this tendency was more pronounced toward the end of the trial (T2 < T1 < T3, p ≤ 0.01). Results from this assay showed that number of flowers/inflorescence was reduced significantly by a mild water deficit treatment, but not the fruit set, having this treatment a positive impact on tree productivity. However, the unirrigated treatment (T2) did not blossom, probably due to the death of the floral bud. Therefore, this fact affected the fruit yield and as a consequence an increased vegetative growth after rewatering period was observed (T2 >T1 = T3, p ≤ 0.01). These preliminary results suggest that only mild water stress could be implemented in the winter period. And this strategy could be a valuable tool to increase the olive tree production in arid argentinean areas.