The reduction of plant sink/source by cluster thinning does not systematically improve the composition of grape

The quality of wine grapes depends on the balance between primary and secondary metabolites. Unlike many perennial crops that accumulate starch in the fruits before ripening, the non-climacteric grapes ripe with no previous carbon reserves. Based on the assumption that fruit carbon sink is limiting metabolite accumulation in grapes, bunch thinning is performed to limit plant Sink/Source (S/S). This post summarizes a study carried out to study the effects of severe bunch thinning on the accumulation of primary metabolites and on four families of glycosylated aroma precursors (GAPs) at the arrest of fruit phloem unloading of two white grape Vitis vinifera cvs. At plant level, crop reduction resulted in significant losses of metabolites to be accumulated in the fruits: i.e. up to 72% for sugars, 75% for organic acids and GAPs. Nevertheless, S/S manipulation could not modify the balance between GAPs and primary metabolites or increase the concentration in GAPs in the physiologically ripe grape.

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Photosynthetic acclimation to high temperature in Syrah and Grenache

Photosynthesis acclimation to high temperature differs among and within species. Grapevine intra-specific variation in photosynthetic acclimation to elevated temperature has been scarcely assessed. A study was carried out to (i) evaluate the mechanisms underlying long-term acclimation of photosynthesis to elevated temperature in grapevine, and (ii) determine whether these responses are similar among two varieties. The study provides evidence that grapevine varieties present different acclimation mechanisms to expected warming.

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Is there an impact of Sound Vibration on Grape Wine?

Understanding the plant microbiome is a key for plant health and controlling pathogens. Recent studies have shown that plants are responsive towards natural and synthetic sound vibration (SV) by perception and signal transduction, which resulted in resistance towards plant pathogens. However, whether or not native plant microbiomes respond to SV and the underlying mechanism thereof remains unknown. Within the present study we compared grapevine-associated microbiota that was perpetually exposed to classical music with a non-exposed control group from the same vineyard in Stellenbosch, South Africa. Results show an as yet unexplored avenue for improved plant health and the terroir of wine, which are important for environmentally friendly horticulture and consumer appreciation. Although our findings explain one detail of the long-term positive experience to improve grapevine’s resilience by this unusual but innovative technique, more mechanistic studies are necessary to understand the whole interplay.

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How remote sensing technology can improve soil & water conservation in vineyards

Hillslope viticulture is a valuable practice across Mediterranean Europe and beyond, not just in economic terms but also for its historical tradition and cultural heritage. Yet, soil degradation such as erosion or slope failure is a growing challenge for cultivators and is threatening the preservation of these landscapes. Future climate projections show a trend of extreme rainfall events, and already nowadays we can witness its impact on soil degradation. In this work, we illustrate how soil and water conservation in vineyards is facilitated by the support of remote sensing technologies such as low-cost drone surveys. Remote sensing allows high-precision mapping of the vineyard ground surface through 3D reconstruction. This can be used to detect, understand or even predict soil degradation, for example by simulating the flow of water and sediments across a vineyard. Such a workflow enables efficient scenario analyses of new vineyard interventions or climatic conditions. Soil protection works can be guided by this workflow for a rapid and low-cost evaluation of new designs. As such, landscape planners are encouraged to utilise this potential to help safeguarding the sustainability of vineyard landscapes.

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Drought impacts on key secondary metabolites: new insights from grape berries to wines

This post reports the results of a study aimed to explore the impact of water deficit on the concentration of key flavour and phenolic secondary metabolites of wines. It was observed that drought-induced compositional changes to the grapes were transferred to the wines, with an increase in polyphenols and volatile organic compounds. However, the timing and the duration of the water stress in the field only heavily impacted the final wine composition with major metabolic modification when the severe water deficit started early and lasted over the entire season until harvest. This study highlights the positive role of a controlled water deficit on the composition of the wines in terms of secondary metabolites

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“Is biodiversity linked with farm management options in vineyard landscapes? A case study combining ecological indicators within a hybrid modelling framework”, Ecological Indicators, 2021

Sustainable management of biodiversity in agricultural landscapes is a European Union objective supported on multifunctional agri-environment measures. The effectiveness of specific practices implemented to reverse declines in farmland biodiversity should be monitored using straightforward methodologies and indicators. This post is about a study which outlined an innovative hybrid framework integrating monitoring, statistics and spatiotemporal modelling procedures to predict the response of biodiversity indicators to farm management options in a viticultural landscape of Portugal, the Demarcated Douro Wine Region.

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Vitis vinifera L. fruit diversity to select or breed varieties anticipating climate changes

The wine industry is facing critical issues due to climate changes since production is established on very tight Genotype × Environment interaction bases. While, some cultivation practices may reduce adverse effects of abiotic stresses on the vines, e.g., the use of irrigation to mitigate drought, the deleterious impacts of warming on fruit development are difficult to manage. Elevated temperature alters grapevine fruit growth and composition, with a critical increase of the sugars/organic acids ratio. Select grapes with improved metabolite balances to offset high temperature effects is a valuable option to sustain viticulture. Unfortunately, the lack of knowledge about the genetic diversity for fruit traits impacted by temperature impairs the design of breeding programs. This study aimed to assess the variation in berry volume, main sugars and organic acids amounts in genetic resources.

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Unmanned aerial vehicles in viticulture

Vineyard blocks can vary spatially with respect to several significant variables such as soil texture and composition, vine vigor, vine physiology, yield components, and berry composition. The ability to detect this variation enables the application of precision viticulture, whereby intra-vineyard variability can be identified and corresponding responses can be made. Unmanned aerial vehicles have only been used for agricultural purposes relatively recently. Satellites and conventional aircraft are still used to obtain aerial images that can be used for research and agricultural purposes.

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Domestication of wild grapevines is still active

Global viticulture has evolved following market trends, causing loss of cultivar diversity and traditional practices. In Montenegro, modern viticulture co-exists with a traditional viticulture that still maintains ancient practices and exploits local cultivars. As a result, this region provides a unique opportunity to explore processes increasing genetic diversity. This post reports the results of a study carried out to evaluate the diversity of Montenegrin grapevines and the processes involved in their diversification. Analyses of genetic structure unveiled several putative proto-varieties, likely representing the first steps involved in the generation of new cultivars or even secondary domestication events.

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Impacts of global warming on southern California’s winegrape climate suitability

Southern California has seen a resurgence of winegrowing regions in the past few decades, however the future of winegrape climatic suitability in the area has not been exhaustively explored. This post reports the results of a study that evaluated the future climate suitability for the cultivation of winegrape and potential global warming impacts on southern California’s winegrowing regions through a series of high-resolution surface air temperature and precipitation projections obtained with the WRF-SSIB regional climate model.

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