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Background and Aims Early defoliation ( ED) can reduce vine yield and improve fruit composition in vigorous vineyards. The objective of this study was to test the effectiveness of this technique for the Vitis vinifera ( L.) cultivar Tempranillo under the temperate warm and semi-arid climatic conditions of south-eastern Spain. Methods and Results Four treatments were applied over three seasons to drip-irrigated vines, planted with rows orientated north-south and shoots vertically positioned. Non-defoliated vines (control) were compared with vines defoliated either just before anthesis (phenological stage H, treatment ED) or at fruitset [phenological stage J, treatment late defoliation ( LD)]. In the fourth treatment, only the leaves facing east were removed at phenological stage H (treatment east ED). In the fourth experimental season, all treatments were managed similarly. Defoliation did not reduce fruitset but reduced berry mass, particularly in the ED and the LD treatments. Defoliation, however, had a cumulative negative effect on vine bud fertility. Even in the fourth experimental season, the yield of the ED treatment was 18% lower than that of the control. Both the ED and particularly the LD treatments increased berry total soluble solids ( TSS) and phenolic concentration. The effect of leaf removal on berry TSS and phenolic concentration was not significant in the east ED treatment. Conclusions Defoliation at fruitset was the most effective treatment for increasing berry phenolics and TSS while maintaining must acidity. Growers should take into account, however, the important yield penalty because of defoliation, particularly in the mid-term. Significance of the Study Early defoliation of Tempranillo grapes growing in semi-arid and temperate climates needs to be applied with caution and probably limited to specific seasons while consecutive defoliations should be avoided. [ABSTRACT FROM AUTHOR]

Background and Aims. High temperatures during grape ripening have a negative effect on the winemaking characteristics of musts. The crop forcing technique delays ripening to a period when temperatures are lower. The objective of this study is to provide information to winemakers and grape growers on how the delay in ripening caused by crop forcing can affect berry performance. Methods and Results. This study of 3 growing seasons (2017–2019) analyzes the effect of this technique in a vineyard of the Vitis vinifera L. cv. Tempranillo in Extremadura, together with two irrigation strategies. The grapevines were forced 4 and 22 days after anthesis (F1 and F2, respectively), compared to a treatment without crop forcing techniques (NF). Each treatment was subjected to two irrigation strategies: to cover the water needs of the plants (C) and deficit irrigation during preveraison (RI). Crop forcing delayed the harvest between 32 and 56 days on average in relation to NF. Crop forcing and irrigation strategy modified berry composition at harvest: C-F1 and C-F2 had higher total polyphenol and anthocyanin concentrations, total acidity, malic acid content, and lower pH relative to C-NF; RI-NF increased total anthocyanin concentration and pH and decreased titratable acidity value. Conclusions. Crop forcing is able to delay grape ripening to lower temperature periods. This is a promising technique for restoring the coupling between phenolic and technological ripeness. The combination of both crop forcing and deficit irrigation strategy maintains the berry quality while improving water use efficiency. Significance of the Study. The present work shows how the "crop-forcing" technique is effective in modifying the relationship between different parameters that determine the characteristics of berries throughout ripening as a raw material for winemaking, compared to vines with traditional winter pruning, under different irrigation strategies. To the memory of Jordi Marsal [ABSTRACT FROM AUTHOR]

Background and Aims: Recently, early defoliation (ED) has been used widely to regulate yield and reduce bunch compactness to improve tolerance to bunch rot. The aim of this study was to test ED, as an alternative to the conventional crop thinning (CT), to regulate yield and improve tolerance to bunch rot of the Vitis vinifera L. cv. Aragonez. Methods and Results: Early defoliation and CT were compared with an untreated Control over three consecutive seasons in a commercial vineyard in Portugal. Early defoliation had little effect on tolerance to bunch rot and led to progressive loss of yield reducing fruitset, bunch number, berry number and mass, compared to Control vines. Reduced bunch number is likely to be a function of reduced bud fertility. Crop thinning also reduced yield but, unlike ED, the yield reduction was less and remained constant over the seasons studied. Both ED and CT had little effect on berry composition. Conclusions: Among the two crop‐regulating techniques, CT appears more suitable than ED to control grape yields in regions where yield limitations are imposed. The progressive yield decline caused by ED is likely to be not economically viable in the region studied. Significance of the Study: Early defoliation reduces bud fertility in unirrigated vineyards under Mediterranean conditions. Therefore, this practice should be avoided under those conditions. [ABSTRACT FROM AUTHOR]

Background and Aims: Available soil water is an important factor determining grapevine yield and grape composition. The aim of this study was to determine the impact of water availability on the yield components and the composition of must and wine of Vitis vinifera L. cv. Verdejo. Methods and Results: The irrigation strategies [rainfed (R0), drip irrigated at 25% ETo (R25) and 50% ETo (R50) applied weekly from the end of the vegetative main shoot growth until harvest] were imposed on white Verdejo grapevines over three consecutive seasons (2012–2014). The 50% ETo treatment resulted in the highest yield. Increasing water availability also reduced the concentration of volatile phenols in all seasons, and of the C6 compounds in 2014 alone. The highest concentration of five individual volatile compounds was associated with the lowest water availability (R0). Conclusions: High water availability increased yield and its components, mainly in the wettest season. Volatile compounds in wine were modified by water regime, with their concentration increased by the most severe deficit irrigation regime (R0). The effect of the year on must and wine composition was greater than the in‐season effects of water availability treatment. Significance of the Study: This study has described the effect of soil water availability on yield and its components and the composition of must and wine of Verdejo. [ABSTRACT FROM AUTHOR]

Background and Aims: Climate change is advancing grape ripening and decoupling sugar and phenolic maturity, impacting wine typicity. The aim of this study was to test whether late leaf removal (LLR) under different watering regimes delayed harvest of two Spanish red cultivars in a semi‐arid and temperate‐warm climate. Methods and Results: In two trials carried out in eastern Spain with the Bobal and Tempranillo cultivars, vines were partially defoliated above the bunch zone shortly before veraison under rainfed and deficit irrigation conditions during two seasons. The rate of grape ripening in both cultivars was significantly affected by LLR under either watering regime, consequently delaying harvest. Vine water status and leaf photosynthetic rate were improved by LLR. The reduction in leaf area‐to‐fruit ratio resulting from the LLR treatments was found to be more limiting for the accumulation of anthocyanin than for TSS. Consequently, LLR negatively affected wine colour intensity. In addition, yield was constrained by LLR in Tempranillo due to a reduction in bunch and berry mass. Conclusions: The reduction in the rate of accumulation of grape TSS provoked by LLR did not necessarily result in a more balanced berry maturity. The effectiveness of the LLR technique appears to depend on its final impact on leaf area‐to‐fruit ratio and vine water status, the cultivar photosynthetic compensation capacity and the environmental conditions. Significance of the Study: Late leaf removal might not be effective for coupling anthocyanin and TSS in berries under moderate water stress conditions, given the observed reductions in red wine colour. [ABSTRACT FROM AUTHOR]

Bunch compactness (or density) is a grapevine specific trait that affects the commercial quality and sanitary status of wine and tablegrapes. Compact bunches are more susceptible to diverse pests and diseases such as Botrytis bunch rot and their berries ripen more heterogeneously, causing important economic losses through a reduction in crop yield and grape and wine quality. Bunch compactness is determined by the fraction of the morphological volume of the bunch that is filled by berries, but this simple definition contrasts sharply with the difficulty to measure it. While there are several objective and quantitative methods available to measure bunch compactness, the lack of a consistent approach between researchers makes comparing measurements difficult. The complexity of bunch compactness initially arises from the several bunch and berry traits that influence it, and from the distinct effects that these traits may cause in different cultivars. In addition to this genetic effect, diverse environmental signals impact on bunch compactness by affecting those primary factors that contribute to the solid component of the bunch (berry number, berry size) or to its spatial arrangement (rachis architecture). Last, several viticultural approaches, including agronomic techniques and growth regulators, have also proven to affect bunch compactness in different ways. This review aims to discuss present knowledge about this relevant grapevine trait. [ABSTRACT FROM AUTHOR]

Background and Aims Irrigation is an important management practice in viticulture. Irrigation scheduling established by previous researchers was based mainly on the irrigation level for optimal berry composition and size at harvest. Because eventual berry size and composition depend on the accumulation of daily growth, a more precise study must be implemented to establish the soil water potential (ψsoil) threshold to trigger irrigation at different development stages of the berry. Methods and Results Photogrammetry, 13 C isotope labelling and other techniques were applied to study the relationship between ψsoil and real-time change of berry expansion, net photosynthetic rate, and the distribution of photosynthetic products in 3-year-old Kyoho grapevines. The diurnal variation of berry size presented a regular pattern, shrinking in daytime and expanding at night. Analysis of a time series model revealed a close correlation between berry growth and ψsoil. With the decline in ψsoil, berry growth presented four phases of change: high speed growth phase, rapid growth phase, slow growth phase and shrinking phase. Conclusions The optimal ψsoil threshold to trigger irrigation at different berry developmental periods was established: −10 k Pa after berry setting (berry diameter < 10 mm), −15 k Pa during berry pea size (berry diameter 10-20 mm) and −20 k Pa after veraison (berry diameter > 20 mm). Significance of the Study The established ψsoil threshold in this study has significant value for the implementation of precision irrigation, which favours normal berry expansion and composition while saving water. [ABSTRACT FROM AUTHOR]

Background and Aims Interactions are the main causes of complexity in field experiments; however, no studies have combined water and temperature regimes in field-growing vines. Here we assessed grape and wine attributes from a field trial where these factors were directly manipulated. Methods and Results The experiment consisted of Shiraz vines grown in a 22 factorial experiment with two temperature (control and heated) and two water regimes (deficit and irrigated) during two seasons (2010/11 and 2011/12). The sensory and compositional characteristics of grapes and wines were assessed in both seasons, whereas a detailed profile of the phenolic substances was determined by spectrophotometry in 2011/12. We found additive effects (i.e. lack of interaction) between temperature and water for berry mass and components, fruit composition (titratable acidity and pH), grape phenolic substances (12.5% ethanol-extracted and most of the 70% acetone-extracted), wine phenolic substances (chemical age 2), and wine sensory traits (floral aromas and berry flavours). Significantly, previously unrecorded interactions between temperature and water were found for grape phenolic substances (70% acetone-extracted skin and seed tannins and total phenolic substances per berry), wine phenolic substances (colour density, tannins and phenolic substances) and wine sensory traits (floral aromas, cooked fruit flavours and tannin structure). Conclusion The effect of water deficit leading to colourful and flavoursome wines rich in phenolic substances may not be held under high temperature. Significance of the Study Our study anticipates the drier and hotter climate of the Barossa Valley, and provides industry with indications of a shift in wine profiles that would require technological innovation to maintain the identity of Barossa Shiraz. [ABSTRACT FROM AUTHOR]

Background and Aims The increasing interest by the wine market in sparkling white wines challenges how the desired grape composition can be achieved under the pressure of global warming. The aim of the present study was to assess the viability of summer pruning as a tool to pilot ripening towards desired compositional patterns. Methods and Results Ortrugo was subjected to basal leaf removal applied either at pre-flowering (ELR) or in lag-phase (LLR) and to bunch thinning ( BT; removal of 50% of crop at lag-phase) in comparison with untreated control ( C). Treatments induced large variation in bunch mass (30% less in ELR vs BT), yield per vine (37 and 21% less in BT and ELR vs C) and total soluble solids at harvest ( BT scored 2.9°Brix higher than that of C). Conversely, given the same harvest date, all practices failed to maintain titratable acidity ( TA) at the threshold of 6.5 g/L. Conclusions The data suggest that crop regulation achieved in the high yielding Ortrugo, through either BT or ELR, increases sugar accumulation rate so that concurrent optimal TA level (≅6.5 g/L) can be easily achieved by slightly anticipating harvest date. Under conditions of thermal or light stress, or weather conducive to bunch rot, preference should be given to ELR. Significance of the Study Suitable summer pruning techniques might be used as flexible and powerful tools to direct ripening towards the desired crop composition. [ABSTRACT FROM AUTHOR]

Background and Aims The influence of water status and bunch thinning on the chemical and sensory properties of V itis vinifera L. cv. Tempranillo wines was studied. Tempranillo vines from Extremadura ( Spain) were subjected to two irrigation treatments (100 and 25% of evapotranspiration) and two bunch-thinning treatments (7-9 and 4-5 bunches/m2 of planting area), applied at veraison. Methods and Results Both thinning and deficit irrigation significantly affected must and wine chemical composition and wine sensory properties. Deficit irrigation increased floral and fruity aromas and reduced herbaceous aromas. The combination of deficit irrigation with bunch thinning improved the sensory characteristics of wines, showing improved colour intensity, persistence and balance. Partial least squares regression showed a correlation among the sensory attributes and chemical composition of Tempranillo wines from different treatments of irrigation and bunch thinning. The sensory attributes, cherry colour, colour intensity, balance and structure, were strongly predicted by anthocyanins, colour intensity and ethanol. Conclusions Deficit irrigation and bunch thinning at veraison improved the sensory characteristics of Tempranillo wines. Improvements due to bunch thinning were independent of those due to irrigation. Significance of the Study Deficit irrigation and bunch thinning at veraison can improve grape composition and wine sensory characteristics in Tempranillo wine. Any improvements, however, must be balanced against a lower yield and the increased management costs of bunch thinning. [ABSTRACT FROM AUTHOR]

Background and Aims The application of deficit irrigation to grapevines modifies the hormonal status of berries, but little information about the influence of berry hormones on phenological sensitivity to water deficit is available. Therefore, the aim of this research was to assess the involvement of berry hormonal status in fruit composition in response to regulated deficit irrigation applied during different phenological stages in two grapevine cultivars. Methods and Results The study was carried out on fruiting cuttings of two cultivars of V itis vinifera L., Tempranillo and Graciano. Treatments were: (i) early water deficit from fruitset to onset of veraison (early deficit); (ii) late water deficit from onset of veraison to harvest (late deficit); and (iii) plants regularly irrigated (Control). Both early water deficit and late water-deficit strategies modified evolution of indole-3-acetic acid, abscisic acid, salicylic acid and jasmonic acid, which was related to changes in berry size, increases in phenolic substances and accumulation of amines. Conclusions Differential sensitivity of Tempranillo and Graciano grapevines to seasonal water stress was mediated, at least in part, by alterations in hormonal status of berries at the time of water stress imposition. Significance of Study This study relates interspecific differences in the sensitivity of seasonal water-deficit irrigation to changes in the endogenous hormonal status of berries. [ABSTRACT FROM AUTHOR]