GIESCO 2023

IVES 9 Tag: GIESCO 2023

Post-spring frost canopy development and fruit composition in cv. Barbera grapevines

One of the effects of warming trends is the advance of budburst, increasing the frequency of spring frost-related damage. In April 2021, a severe frost event affected central and northern italian viticulture. In a cv. Barbera vineyard located in the Colli Piacentini wine district, after such occurrence, vines were tracked and growth of primary bud shoots (PBS), secondary bud shoots (SBS), and suckers (SK) was monitored, as well as their fruitfulness and fruit composition. Vine performances were then compared to those of the previous year, when no post-budburst freezing temperatures occurred. The goal of the study was to evaluate the efficacy of SBS in restoring yield loss due to PBS injuries and analyze respective contribution to fruit composition.

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Precipitation variability in a temperate coastal region and how it affects Tannat and Albariño cultivars 

Climate is one of the main components that defines the development and behavior of the plant, conditioning the health status and the final quality of the grapes. In temperate coastal climates such as in Uruguay (latitude 35° S, longitude 55° O), precipitations during the growing season present high interannual variability, with a average of 100 mm per month. This variability means that plants must adapt to conditions from one year to the next.

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The effect of water stress deficit on ‘Xynisteri’ grapes through systems biology approaches

Cyprus is one of the very few phyloxera-free areas worldwide where the vast majority of vines are own-rooted and non-irrigated. ‘Xynisteri’ is a predominant indigenous cultivar, particularly amenable to extreme conditions such as drought and hot climate, thus rendering it appropriate for marginal soils and adverse climatic conditions. In the current work, a comparative study between irrigated (irrigation initiated at BBCH 71) and non-irrigated vines was conducted.

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The effects of cover cropping systems on vine physiology, berry and wine quality in a climate change scenario in Switzerland

Sustainable weed control with little detrimental effects on vine physiology, yield, berry quality, soil structure, health and biodiversity is a key factor in vineyard management. Few options are available to avoid herbicide utilization and minimize negative effects of frequent tillage on soil quality. The present project aims to investigate and develop different cover management strategies in a cool climate viticultural region in Switzerland. The impact of different treatments on vine, must and wine has been studied in an experimental vineyard in Changins, Switzerland for one year and will be continued over the next three years.

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Ripening behaviour and grape must quality of eleven white resistant varieties in Trentino

In a situation of uncertainty towards the overall effect of climate change and the reduction of pestice utilization on quality, the wine sector needs to maintain the profitability of producers, which inexorably depends on ensuring the quality of grapes and wines. Among the various alternatives that can be adopted, hybrid varieties carrying resistance genes are currently gaining the attention of researchers and producers. Some of them are already a reality and are included in the national catalogue of some countries, selected by research institutes all over Europe.

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Survey of winegrape irrigation practices in the Sacramento-San Joaquin Valley of California

In California vineyards, irrigation is considered as one of the most important decisions growers will make. Recent research has revealed that decisions of when to begin irrigation and how much water to apply have considerable consequences for final grape quality and hence wine quality. However, it is unclear whether and to what extent the average winegrape grower uses objective data to begin irrigating or to determine the amount of water to apply.

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Drought lessons: long-term effects of climate, soil characteristics, and deficit irrigation on yield and quality under high atmospheric demand in the Douro Region

Global warming is one of the biggest environmental, social and economic threats in several viticultural regions. In the Douro Valley, changes are expected in the coming years, namely an increase in temperature and a decrease in precipitation. These changes are likely to have consequences for the production and quality of wine.

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Uncovering the effectiveness of vineyard techniques used to delay ripening through meta-analysis

One of the most concerning trends associated with increasing heat and water stress is advanced ripening of grapes, which leads to harvesting fruit at higher sugar concentrations but lacking optimal phenolic (i.e. color and mouthfeel) and aromatic maturity. Mitigation techniques for this phenomenon have been studied for many years and practices to delay sugar accumulation have been identified, including antitranspirants, delayed pruning and late-source-limitation techniques. Evaluation of the efficacy of these vineyard practices has occurred across a wide range of environments, vintages, varieties and growing conditions. To assess the broader efficacy of these three vineyard practices, which are easy-to-implement and cost-effective, a meta-analytic approach was adopted using data retrieved from 43 original studies.

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Towards microbiota-based disease management: analysis of grapevine microbiota in plots with contrasted levels of downy mildew infection

Vineyards harbor a myriad of microorganisms that interact with each other and with the grapevines. Some microorganisms are plant pathogens, such as the oomycete Plasmopara viticola that causes grapevine downy mildew. Others, such as plant growth promoting bacteria and disease biocontrol agents, have a positive influence on vine health. The present study aims to (1) investigate whether vine-based culture media increase the cultivability of the grapevine microbiota, in comparison to standard culture media and (2) identify and isolate bacterial taxa naturally present in grapevine leaves and significantly more abundant in plots showing low susceptibility to downy mildew.

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Impact of soil-applied and foliar-applied nitrogen on grape and wine composition

Foliar application of urea may be an efficient way to alter grape and wine composition without increasing vine vigor. However, we know little about the impact of this practice on phenolic compounds and yeast assimilable nitrogen (YAN). Adequate YAN is required for an efficient and complete fermentation, while phenolics are particularly important for the sensory profile of red wines. The goal of this study is to test the impact of foliar urea application at veraison, compared to the traditional soil-applied nitrogen fertilization early in the season, on Syrah berry and wine composition in field conditions.

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Grapevine nitrogen status: correlation between chlorophyll indices n-tester and spadGrapevine nitrogen status

Knowledge of the nitrogen nutrition status of grapevines is essential for the sustainable management of their nutrition for the production of quality grapes. The measurement of the chlorophyll index is a rapid, non-destructive and relatively inexpensive method that provides a good approximation of the nitrogen nutrition status of the vine during the season. Interpretation thresholds are currently insufficient or non-existent for some chlorophyll meters. Ideally, they should be available for each variety and each phenological stage. In order to popularize the use of chlorophyll-meters, measurements were carried out at Agroscope in Switzerland to establish the correlation between the indices obtained by the devices N-tester and SPAD 502.

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Rootstock effects on cv. Ugni blanc berry and wine composition

In the Cognac region in France, Ugni blanc is the most planted grape variety (98% of the 80 500 ha). This vine region is in expansion due to the success of the associated well-known brandy and the need of high grape yield to guarrantee the production of base wine for distillation. About 2 to 3000 ha are newly planted each year and rootstocks are one powerfull tool for vineyard adaptation to soil or climate change. As rootstocks ensure water and mineral nutrient supplies to the scion, it is important to better understand their effect on berry compostionnal parameters such as sugars and nitrogen compounds, which are the main precursors for fermentary aroma metabolites, the latter being quality markers for Cognac after distillation.

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Under-vine cover crops as a management tool for irrigated Mediterranean vineyards: agronomic implications and changes in soil physical and biological properties 

Cover crops are increasingly considered in Mediterranean climate vineyards due to a combination of agronomic and regulatory considerations. However, the soil under the vines themselves is typically kept free of vegetation by mechanical plowing or herbicide spraying. Taking into account that these practices may convey a number of non-favourable economic and environmental implications, and the fact that drip irrigation can ease the use of cover crops under the vines, the aim of this work was to evaluate the agronomic implications and the changes in soil physical and biological properties caused by an under-vine cover crop in a Mediterranean area.

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Relative impact of crop size and leaf removal on aromatic compounds and phenolic acids of Istrian Malvasia wine

Although several studies investigated the impact of crop size or fruit zone microclimate on aromatic or phenolic composition of wines, the effects of these two practices were not assessed and compared in the same study through a technological experiment within the same vineyard. Therefore, their relative effectiveness is hard to compare, which in turn is essential for providing producers with valuable information as a basis to choose adequate approach in yield and canopy management. The aim of the study was to investigate the effects of two crop sizes and two different fruit zone microclimate conditions obtained by leaf removal in a two-factorial experiment, in order to assess and compare their relative impact on Istrian Malvasia (Vitis vinifera L.) white wine aroma and phenolic composition.

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Comparing different vineyard sampling densities and patterns for spatial interpolation of intrinsic water use efficiency

The need to rationalize agricultural inputs has recently increased interest in assessing vineyard variability in order to implement variable rate input applications, so-called ‘precision viticulture’. In many viticultural areas globally, precision viticulture is already widely used such as for selective harvesting and variable rate application (VRA) of inputs such as irrigation and/or fertilizer. Robust VRA relies on having a geostatistically accurate map (of one or more vineyard attributes) requiring high sampling densities, which can be cost- and time-prohibitive to obtain. Previous work on spatial interpolation using kriging have upscaled ground-based measurements, but such upscaling strategies are applicable only when vineyard conditions are spatially continuous and satisfies the assumption of second-order stationary processes. Alternatively, mixed models that combine kriging and auxiliary information, such as the regression kriging (RK) method, are more instructive for spatial predictions. In order to improve prediction accuracies, it is therefore necessary to incorporate additional information to achieve accurate spatial patterns with low error.

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Biomass carbon and nitrogen input from cover crops in an irrigated vineyard in Okanagan Valley, Canada

The use of cover crops in vineyards has been encouraged by positive effects on wine grape yield and sensory attributes, and improved soil function. This study examined the efficacy of three alleyway and three undervine cover crop treatments in an organic vineyard in the semiarid Okanagan Valley, Canada in 2021.

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Implications of the respect of pruning principles on grapevine development

After some decades sunk into oblivion, pruning has recently recovered the focus of grape growers and viticulturists worldwide. Attention is now being paid to the respect the sap flow continuity and to pruning wounds, as they may affect the general performance and longevity of the plant. The longevity and profitability are strongly affected by the increasing incidence of grapevine wood diseases (GWD), intensified by the omission of good pruning practices and leading to an increasingly aggressive pruning. The purpose of this study is to provide an objective evaluation of the short- and mid-term implications of different pruning practices that differ in the degree of observation several of pruning principles.

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An overview of the impact of clone, environmental factors and viticultural techniques on rotundone concentration in red wines

Rotundone is the main aroma compound responsible for peppery notes in red wine. This positive and very potent molecule has an odor threshold of 8 ng/L in water and 16 ng/L in red wine. It has been detected in several grape varieties with some of the highest concentrations recorded in Syrah, Duras, Tardif and Noiret, an interspecific hybrid grown in the North-East of the USA. If several winemaking practices have been identified to lower rotundone in wine, up to date, no enological solution has proved its efficiency to maximize it. This means that efforts to produce high rotundone wines must be undertaken in vineyards. This work provides practical ways that can be used by winegrowers to modulate rotundone levels in their wines.

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