Irrigation is one of the most important means of increasing olive oil production but little information exists on the responses of olive to variable water supply. Five different irrigation strategies, full irrigation, rain fed, and three deficit irrigation treatments were compared from 1996 to 1999, in Cordoba, southern Spain, to characterize the response of a mature olive (Olea europaea L. `Picual') orchard to irrigation. Crop evapotranspiration (ET_c) varied from less than 500 mm in the rain fed to ≈900 mm under full irrigation. The deficit irrigation treatments had ET_c values that ranged from 60% to 80% of full ET_c depending on the year and treatment. Water relations, and oil content and trunk growth measurements allowed for the interpretation of yield responses to water deficits. In a deficit irrigation treatment that concentrated all its ET_c deficit in the summer, stem water potential (Ψ_x) decreased to -7 MPa but recovered quickly in the fall, while in the treatment that applied the same ET deficit progressively, Ψ_x was never below -3.8 MPa. Minimum Ψ_x in the rain fed treatment reached -8 MPa. Yield (Y) responses as a function of ET_c were calculated for biennial yield data, given the alternate bearing habit of the olive; the equation are: Y = -16.84 + 0.063 ET -0.035 × 10^-3 ET², and Y = -2.78 + 0.011 ET - 0.006 × 10^-3 ET², for fruit and oil production respectively, with responses to ET deficits being similar for sustained and regulated deficit irrigation. The yield response to a deficit treatment that was fully irrigated during the bearing year and rain fed in the nonbearing year, was less favorable than that observed in the other two deficit treatments.

14 páginas.-- 4 figuras.-- 3 tablas.-- 147 referencias.-- : Galindo,A., et al...Water scarcity in Mediterranean climate areas will be progressively aggravated by climate change, population increase and urban, tourism and industrial activities. To protect water resources and their integrity for future use and to improve biodiversity, besides following advanced deficit irrigation strategies in fruit cultivation, attention could well be directed towards what are at present underused plant materials able to withstand deficit irrigation with minimum impact on yield and fruit quality. To this end, the state of the art as regards deficit irrigation strategies and the response of some very interesting emerging fruit crops [jujube (Zizyphus jujuba Mill.), loquat (Eriobotrya japonica Lindl.), pistachio (Pistacia vera L.) and pomegranate (Punica granatum L.)] are reviewed. The strengths and weaknesses of deficit irrigation strategies and the mechanisms developed by these emerging fruit crops in the face of water stress are discussed. The response of these crops to deficit irrigation, with special attention paid to the effect on yield but also on fruit quality and health-related chemical compounds, was analysed in order to assess their suitability for saving water in Mediterranean semiarid agrosystems and to analyze their potential role as alternatives to currently cultivated fruit crops with higher water requirements. Finally, the factors involved in establishing an identity brand (hydroSOS) to protect fruits obtained under specific DI conditions are discussed.We are also grateful to the Ministerio de Economía y Competitividad de España (MINECO) (CICYT/FEDER AGL2013-45922-C2-1-R, AGL2013-45922-C2-2-R, AGL2016-75794-C4-1-R and AGL2016-75794-C4-4-R) for grants to the authors. AG and JC-G acknowledge the postdoctoral financial support received from the Ramón Areces Fondation and the Juan de la Cierva program, respectively. Also, this work is a result of the PR internship (19925/IV/15) funded by the Fundación Séneca – Agencia de Ciencia y Tecnología de la Región de Murcia (Seneca Foundation – Agency for Science and Technology in the Region of Murcia) under the Jiménez de la Espada Program for Mobility, Cooperation and Internationalization.Peer reviewe