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- Response of grapevine CV. “Tinta roriz” (Vitis vinifera L.) to moderate irrigation in the Douro Region, PortugalPublication . Ribeiro, A.C.; Andrade, João VerdialThe behaviour of cv. “Tinta Roriz” (Vitis vinifera L.), was studied when moderate drip irrigation was applied from veraison to harvest. Field studies were conducted during three growing seasons (2006-2008) in a commercial vineyard located in the Douro region, Portugal. Experimental layout consisted in the measurement of physiological and agronomic parameters in vines submitted to three different irrigation treatments: 0R was non-irrigation, 2R and 4R were irrigated with a constant fraction of reference evapotranspiration of 0.2 and 0.4, respectively. The results showed that moderate irrigation improved plant water status, leaf photosynthesis and transpiration. Yield components and pruning weights had a significant increase, only in the 2008 growing season, in 4R irrigated treatment. There were no significant differences between treatments in the accumulation of sugar, titratable acidity and pH in berries. The total phenols and the colour intensity showed a tendency, not significant, to decrease in irrigated treatments.
- Effect of two grapevine (Vitis vinifera L., cv Tinta Roriz) trainning systems on leaf gas exchange and water use efficiencyPublication . Ribeiro, A.C.; Andrade, João VerdialTraining systems which allow partial or full mechanization and facilitate hand management due to their simpler structure and pruning are therefore becoming more appealing to growers. In Trás-os-Montes region (northeastern Portugal) grapevine “traditional” training system (small bush vines close to the ground with no foliage support wires) have been reconverted mainly to non-irrigated unilateral and bilateral cordon training systems with a typical upright shoot growth supported by catch wires. In this hot and dry region, limitations in water supply have a great impact on grape production as the annual rainfall is not adequate to provide grapevines with their water requirements, and water deficits usually develop gradually during summer. In this study two non-irrigated grapevine training systems (traditional small bush vines close to the ground (TSB) and bilateral cordon with vertical shoot positioned vines (VSP))were compared for their effects on physiological performance and water use efficiencyin Mediterranean weather conditions. The trial was carried out in a 25-year old experimental vineyard planted with cv. Tinta Roriz in Trás-os-Montes region (Planalto Mirandês sub-region). Experimental layout consisted in the measurement of physiological variables (net CO2 assimilation rate (A), stomatal conductance (gs) and transpiration rate (E)) and pre-dawn and midday leaf water potential at the veraison and maturity on fully exposed leaves. The grapevines trained in TSB showed a higher water status (lower predawn and midday leaf water potencial), lower transpiration rate (E), lower stomatal conductance (gs) and higher intrinsic water use efficiency (A/gs). These preliminary results show that grapevine “traditional” training system, with no irrigation, seems to be well adapted to this hot and dry region.
- Assessing the risk of tropospheric ozone phytotoxic effect on Southern European Mediterranean environments: a review with emphasis on vineyardsPublication . Blanco-Ward, Daniel; Miranda, Ana Isabel; Silveira, Carlos; Ascenso, Ana; Gama, Carla; Monteiro, Alexandra; Lopes, Myriam; Borrego, Carlos S.; Ribeiro, A.C.; Feliciano, Manuel; Castro, João Paulo; Andrade, João Verdial; Barreales, David; Viceto, Carolina; Rocha, Alfredo; Carlos, CristinaTropospheric ozone in Southern Europe has an increasing tendency in association with a greater incidence of warm summers and heatwaves. As there is already much evidence of the negative effects that current ambient ozone has on vegetation, there is a need for consistent risk assessment methods. Ozone plant exposure-based parameters have been used extensively to support decision-making. However, these parameters have been also criticised, as they do not relate with the actual dose of ozone entering the plant. Moreover, in Mediterranean environments, they often overestimate the risk as thresholds are exceeded without corresponding evidence of damaging effects. To overcome these limitations, dose-based approaches were developed. These approaches have a stronger biological basis as they are based on estimates of the amount of ozone molecules that diffuse into the leaf cells through the stomata. However, they have also limitations, as detoxification processes or non-stomatal uptake are not often taken into consideration. This work presents a review regarding ambient ozone effects on vegetation and the indices used to assess phytotoxic risk in southern European Mediterranean plant communities and crops. Emphasis is given to the grapevine as three southern European countries (Spain, Italy and Portugal) are major wine producers concentrating more than 20% of the area under grapevines globally. These countries hold a long winemaking tradition associated to renowned denominations of origin (DOs). Therefore, there is concern regarding climate change as a potential threat to wine typicity in these areas, most of the work focusing on atmospheric variables, bioclimatic and climate change indices only. Results from the DOUROZONE project are presented with the aim to analyse the implications climate change can have in a significant Portuguese wine region such as the Douro Demarcated Region (DDR) including ozone-related indices as a novelty among other more frequently used bioclimatic and climate change indices.
- Response of grapevive CV. “Tinta Roriz (Vitis vinifera L. ) to moderate Irrigation in the Douro Region, PortugalPublication . Ribeiro, A.C.; Andrade, João VerdialThe behaviour of cv. “Tinta Roriz” (Vitis vinifera L.), was studied when moderate drip irrigation was applied from veraison to harvest. Field studies were conducted during three growing seasons (2006-2008) in a commercial vineyard located in the Douro region, Portugal. Experimental layout consisted in the measurement of physiological and agronomic parameters in vines submitted to three different irrigation treatments: 0R was non-irrigation, 2R and 4R were irrigated with a constant fraction of reference evapotranspiration of 0.2 and 0.4, respectively. The results showed that moderate irrigation improved plant water status, leaf photosynthesis and transpiration. Yield components and pruning weights had a significant increase, only in the 2008 growing season, in 4R irrigated treatment. There were no significant differences between treatments in the accumulation of sugar, titratable acidity and pH in berries. The total phenols and the colour intensity showed a tendency, not significant, to decrease in irrigated treatments.