Tempranillo physiological and agronomical responses to heat and drought stress – perspectives on its vulnerability under climate change scenarios

With the aim to characterize the ability of Tempranillo grapevines, one of the most widely used varieties in Spain and Portugal, to withstand drought and heat stress, ecophysiological and agronomical data from irrigation experiments conducted in the hot and dry region of Alentejo, south of Portugal, are presented. The impact of different irrigation treatments on physiological parameters (leaf water potential, photosynthesis, and stomatal conductance) and water use efficiency are showed. Leaf senescence observed in non-irrigated and deficit irrigated plants and its consequences on cluster exposure and berry temperature are compared with those of fully irrigated plants. The consequences on berry ripening and juice composition are discussed in order to evaluate the vulnerability of Tempranillo to the expected global climatic changeinfo:eu-repo/semantics/publishedVersio

Effects of soil management and deficit irrigation strategies on physiological and agronomical responses of Aragonez field-grown grapevines

The use of irrigation in Mediterranean viticulture is now a common practice in intensive grapevine production to improve quality of production. The negative effects of water deficits on grape berry development are well known but the underlying mechanisms remain not fully understood. To avoid the unfavourable impacts of mechanization on the soil structure and biology some farmers are using cover crops on their vineyards. Within this frame we have compared the traditional soil tillage with a high level of mechanization with other system where we maintained a permanent soil cover between the rows. In both soil systems we tested three different irrigation treatments, deficit irrigation (DI - 40% of evapotranspiration (ETc)); regulated deficit irrigation (RDI); partial root drying (PRD) while in the soil cover treatment we also studied the full irrigation (FI) and the non irrigation (NI) treatments. Compared to soil tillage the resident vegetation reduced soil water content during late Spring, before irrigation started, inducing a significant reduction on vine vegetative growth berry weight and yield. Among irrigation strategies only RDI treatment showed a significant reduction in the lateral leaf area development, berry weight and yield when compared to PRD and DI treatments which presented similar values. No significant differences were observed in berry composition either for the two floor management practices or for the three irrigation strategiesinfo:eu-repo/semantics/publishedVersio

An attempt to quantify grapevine water stress in a mediterranean environment

Aiming to quantify the effects of the intensity and duration of grapevine water stress, physiological and agronomical data from an irrigation experiment conducted during 1999 at Alentejo, south of Portugal, with the red variety Aragonez (syn. Tempranillo) were correlated with an water stress index (Sψ). This index was calculated by the integral of predawn leaf water potential below –0.2 MPa between bloom and harvest. Significant relationships were found between the Sψ, yield components and berry composition. The multiple regression analysis shows that the Sψ in the period bloom-veraison has a higher contribution to explain the variation in berry weight, anthocyanins and phenolics concentration than the Sψ in the period veraison-harvest. The knowledge of those relationships, together with the relationship between available soil water content and predawn leaf water potential, may allow the adequate management of soil water availability to optimise the yield/quality ratio for each ecological situationinfo:eu-repo/semantics/publishedVersio

Relationships between leaf water potential and photosynthetic activity of field grapevines grown under different soil water regimes

Relationships between ecophysiological parameters from a grapevine irrigation experiment (rain-fed vs. deficit irrigation) conducted during 1998 at Alentejo, south of Portugal, with the red variety Aragonez (syn. Tempranillo) are presented and discussed. The irrigation affected positively grapevine physiology without changing berry composition. Predawn leaf water potential shows a significant dependence on available soil water, measured by a neutron probe, the correlation coefficients being higher in nonirrigated plants than in irrigated ones. Leaf water potential (Ψ) values measured in exposed leaves in the morning and afternoon were also significantly correlated with available soil water. Net CO2 assimilation rate (A) and stomatal conductance (gs) of sun leaves measured throughout the growing season at three different periods of the day were significantly correlated with predawn leaf water potential, nonirrigated vines presenting the highest correlation coefficients. Significant correlations were also found between Ψ and A or gs measured in the early morning. Our results show that, in water stress conditions, predawn leaf water potential can be used as an indicator of soil water availability and physiological activity of sun exposed leavesinfo:eu-repo/semantics/publishedVersio

Deficit irrigation in Mediterranean vineyards - a tool to increase water use efficiency and to control grapevine and berry growth

IHC - IS Viti&Climate: Effect of Climate Change on Production and Quality of Grapevines and their Products, 28 th, 2012Water is increasingly scarce in Mediterranean Europe and irrigated agriculture is one of the largest and most inefficient users of this natural resource. Ecological topics such as the “water foot print” have become more relevant for the academy, consumers, governments and food industry. The wine sector needs solutions to improve its economical and environmental sustainability. Agronomical solutions, such as deficit irrigation (water supply below full crop evapotranspiration) have emerged as a tool for more efficient water use in irrigated viticulture and with likely positive effects on berry quality. Improving our understanding on the physiological and molecular basis of grapevine responses to water stress is an important task for research on irrigated viticulture. Better knowledge of the different genotypic responses (e.g., leaf gas exchange) to water stress can help to optimize crop/soil management and improve yield as well as berry quality traits under unfavourable climate conditions. Mild water deficits have direct and/or indirect (via the light environment in the cluster zone) effects on berry growth and composition. Another important challenge is to determine how soil water deficit regulate genes and proteins of the various metabolic pathways influencing berry composition and consequently wine quality

Grapevine under deficit irrigation: hints from physiological and molecular data

Background - A large proportion of vineyards are located in regions with seasonal drought (e.g. Mediterraneantype climates) where soil and atmospheric water deficits, together with high temperatures, exert large constraints on yield and quality. The increasing demand for vineyard irrigation requires an improvement in the efficiency of water use. Deficit irrigation has emerged as a potential strategy to allow crops to withstand mild water stress with little or no decreases of yield, and potentially a positive impact on fruit quality. Understanding the physiological and molecular bases of grapevine responses to mild to moderate water deficits is fundamental to optimize deficit irrigation management and identify the most suitable varieties to those conditions. Scope - How the whole plant acclimatizes to water scarcity and how short- and long-distance chemical and hydraulic signals intervene are reviewed. Chemical compounds synthesized in drying roots are shown to act as long-distance signals inducing leaf stomatal closure and/or restricting leaf growth. This explains why some plants endure soil drying without significant changes in shoot water status. The control of plant water potential by stomatal aperture via feed-forward mechanisms is associated with ‘isohydric’ behaviour in contrast to ‘anysohydric’ behaviour in which lower plant water potentials are attained. This review discusses differences in this respect between grapevines varieties and experimental conditions. Mild water deficits also exert direct and/or indirect (via the light environment around grape clusters) effects on berry development and composition; a higher content of skin-based constituents (e.g. tannins and anthocyanins) has generally being reported. Regulation under water deficit of genes and proteins of the various metabolic pathways responsible for berry composition and therefore wine quality are reviewed

Deficit irrigation in Mediterranean environment. What lessons have we learnt from grapevine studies ?

Libro de Actas - X Simposium Hispano Português de Relaciones Hidricas, 2010Deficit irrigation techniques, implying that water is supplied at levels below full crop evapotranspiration throughout the growing season or in specific phenological stages, such as regulated deficit irrigation (RDI) or partial root drying (PRD), emerged as potential strategies to increase water savings with marginal decreases of yield and likely positive impact on fruit quality. Understanding the physiological and molecular bases for plant responses to mild to moderate water deficits is of utmost importance to modulate the appropriate balance between vegetative and reproductive development, to improve crop water-use efficiency and to control fruit quality. It is acknowledged that the timing and intensity of the response to soil and atmospheric water deficits, namely in what concerns stomatal control, depends greatly on the genotype. This has profound implications in irrigation management, in particular the timing and amount of irrigation to optimize source-sink relationships and achieve optimal fruit quality in each variety. Mild water deficits also exert direct and/or indirect (via the light environment in the cluster zone) effects on berry development and composition. A current research challenge is determining how the environment, in particular water deficits, regulates genes and proteins of the various metabolic pathways responsible for berry composition and therefore for wine qualit

Respuestas fisiológicas y agronómicas de la variedad Tempranillo a la tensión del calor y de la sequía – perpectivas en su vulnerabilidade bajo panoramas del cambio climático

Con el objetivo de caracterizar la habilidad de las vides de tempranillo, una de las variedades más usadas en España y Portugal, de resistir el estrés producido por las sequías y el calor, se presenta información ecofisiológica y agronómica obtenida de los experimentos de irrigación llevados a cabo en la cálida y seca región de Alentejo, en el sur de Portugal. Se muestra el impacto de los diferentes tratamientos de irrigación en los parámetros fisiológicos (el potencial de agua de la hoja, fotosíntesis y la conducción estomatal) y la eficiencia en el uso del agua. La senectud de las hojas que se observó en las plantas no regadas o con déficit en el riego y las consecuencias en la exposición del racimo y la temperatura de las uvas se comparan con las de plantas con riego adecuado. Se discuten las consecuencias en la maduración de las uvas y la composición del jugo para evaluar la vulnerabilidad del tempranillo al esperado cambio climático globalWith the aim to characterize the ability of Tempranillo grapevines, one of the most widely used varieties in Spain and Portugal, to withstand drought and heat stress, ecophysiological and agronomical data from irrigation experiments conducted in the hot and dry region of Alentejo, south of Portugal, are presented. The impact of different irrigation treatments on physiological parameters (leaf water potential, photosynthesis, and stomatal conductance) and water use efficiency are showed. Leaf senescence observed in non-irrigated and deficit irrigated plants and its consequences on cluster exposure and berry temperature are compared with those of fully irrigated plants. The consequences on berry ripening and juice composition are discussed in order to evaluate the vulnerability of Tempranillo to the expected global climatic changeinfo:eu-repo/semantics/publishedVersio

Técnicas para manipulação do vigor da videira e da qualidade da uva: rega deficitária e enrelvamento da vinha

Em regiões de clima mediterrânico, como é o caso de várias regiões vitícolas portuguesas, as estratégias de rega deficitária têm sido utilizadas com sucesso como técnicas culturais para controlo do crescimento vegetativo da videira e melhoria da qualidade da uva. O enrelvamento da vinha tem sido também uma técnica de manutenção do solo muito utilizada no mundo vitícola, sobretudo em regiões com precipitação no verão ou com possibilidades de rega. As vantagens da utilização do enrelvamento, natural ou semeado, são várias, indo desde os benefícios para o ambiente até à gestão da vinha, designadamente através do controlo do vigor e consequente melhoria da qualidade da uva através da redução da densidade da sebe e da competição vegetação/frutificação. Apesar destas vantagens potenciais, a utilização dos relvados em vinhas de sequeiro de regiões mediterrânicas tem sido limitada sobretudo devido ao receio de uma excessiva competição hídrica entre a vegetação dos relvados e a videira. Com o objectivo de discutir as implicações destas técnicas culturais no vigor da videira e na composição da uva, serão apresentados resultados de ensaios realizados pelo nosso grupo em duas regiões vitícolas nacionais e com duas castas tintas. Serão abordados os principais efeitos das estratégias de rega deficitária (rega deficitária controlada e rega parcial das raízes) e das técnicas de manutenção do solo (mobilização vs enrelvamento) no uso da água, no crescimento vegetativo e suas consequências no microclima dos cachos, rendimento e qualidade da uva. Os potenciais benefícios e desvantagens das várias estratégias serão discutidosinfo:eu-repo/semantics/publishedVersio