Aim: To compare grape yield prediction methods to determine which provide the best results in terms of earliness of prediction in the growing season, accuracy and precision.Methods and results: The grape yields predicted by six models – one for use at fruitset (FS), two for use at veraison (V1 and V2), and three for use during the lag phase (LP40, LP50 and LP60) – were compared to field-measured yields. Regressions for the yield predicted by each model were constructed. The V1 and V2 models had the highest R2 (0.75) and efficiency index (EF; 0.67-0.71) and the lowest RMSE values (±16-17%, or <0.5 kg per m of row). The FS model had the same or similar R2 (0.58), EF (0.06) and RMSE (±30%, or <0.83 kg per m of row) values as the LP models, but allowed yield predictions to be made one month earlier.Conclusion: The validated FS, V1 and V2 models are all useful in predicting grape yields and could be used to accurately forecast (with different errors) grape yields at either early or later time points according to winery needs. These models could be improved as further data become available in following seasons.Significance and impact of the study: Few validated models are available for predicting grapevine yields at fruitset and veraison. This study provides predictive models that can be used at these different times of the growth cycle.

Vineyard leaf area is a variable that must be determined when assessing the productive potential of a vineyard and for characterizing the light and thermal microenvironments of grapevine plants. The aim of the present work was to validate the Lopes and Pinto method for determining vineyard leaf area in the vineyards of central Spain and with the area’s cultivars. The results obtained were compared to those provided by a traditional and accurate —but much more laborious— non-destructive direct method. Experiments were performed over three years in six vineyards growing either cvs. Syrah, Cabernet Sauvignon, Cabernet franc, Merlot or Tempranillo. Good agreement was found between the two methods both in the determination of primary and lateral shoot leaf areas for all cultivars and vineyards. The simplicity of the Lopes and Pinto method means much larger sample sizes can be examined in the same period of time, increasing the accuracy of final vineyard leaf area values. In fact, regression analysis of the data collected for the Lopes and Pinto method showed that only three field-measured variables need to be recorded for the inspected shoots of either type: the area of the largest leaf, the area of the smallest leaf, and the number of leaves.

Copper (Cu) and its based preparations have been used for over 200 years to control fungi and bacterial diseases in cultivated plants. Downy mildew caused by the obligate biotrophic oomycete Plasmopara viticola is one of the most relevant and recurrent diseases of grapevines. Recently, the use of Cu is being limited by some regulations because of its high impact at different levels (health and environmental problems). Due to its accumulation in soil, this metal causes a little controversy with the principles of sustainable production. Therefore, international legislation and initiatives have recently been arisen to start limiting its use, with the main goal to replace it. In this framework, some alternatives have been tested and others are recently being developed to replace, at least partially, the use of Cu in viticulture. Many of them, are being developed and tested under the scope of research and development EU funded projects. To not compromise sustainability targets in viticulture, results from these R&D projects need to be considered to assess the present risks of using Cu in viticulture and to better support establishing limits for its applications, considering soils vulnerability, while no sustainable alternatives are available in the market.

Historically, certain physiological behaviours were typically attributed to genetic factors. However, some grape varieties exhibit different responses depending on crop management and environmental conditions. The present study examines whether the physiological responses of grapevines traditionally attributed to genotypic traits (near-isohydric or near-anisohydric behaviour) can instead be substantially modified by canopy architecture. The objective was to determine how canopy management influences water relations (leaf water potential—Ψ_L), physiological plant responses (water use efficiency (WUE), stomatal conductance (gs), transpiration (E) and photosynthetic (A) rates), and radiation interception efficiency (εi), particularly under warm Mediterranean conditions. To test this, two training systems were evaluated in a Syrah vineyard: a vertical shoot position (VSP1) and a sprawl (S1) system with 12 shoots·m⁻¹, under the same irrigation regime. The results showed that under stressed conditions (high vapor pressure deficit [VPD] and relatively lower Ψ_L, from −1.4 to −0.6 MPa), the S1 system—despite a similar leaf area index, LAI—exhibited lower gs values than those of the VSP1 system (10–30%), with plants closing their stomata to reduce water consumption and prevent their dehydration caused by steep E rates. Meanwhile, the VSP vines exhibited higher gs values (isohydric-like response), indicating higher E rates, which reduced their WUE and intrinsic water-use efficiency (IE). This strategy (similar to the anisohydric one) allowed the S1 treatment to obtain higher WUE and interception radiation efficiency (εi) ratios, even at low Ψ_L (more efficient), produced by the higher canopy demand (more exposed surface area [SA]). These contrasting behaviours indicate that sprawl systems can enhance radiation interception and WUE compared with vertical systems under semiarid Mediterranean conditions.