GiESCO 2019 banner
IVES 9 IVES Conference Series 9 GiESCO 9 Diversity in grape composition for sugars and acidity opens options to mitigate the effect of warming during ripening

Diversity in grape composition for sugars and acidity opens options to mitigate the effect of warming during ripening

Abstract

Context and purpose of the study – The marked climate change impact on vine and grape development (phenology, sugar content, acidity …) is one of the manifestations of Genotype X Environment X Management interactions importance in viticulture. Some practices, such as irrigation, can mitigate the effect of water deficit on grape development, but warming is much more difficult to challenge. High temperatures tend to alter the acid balance of the fruit with a parallel increase in sugar concentration. In the long term, genetic improvement to select varieties better coping with temperature elevation appear as a good option to support sustainable viticulture. Nevertheless, the existing phenotypic diversity for grape quality components that are influenced by temperature is poorly understood, which jeopardizes breeding strategies. The purpose of this study was to characterize the phenotypic diversity present in the genetic resources of Vitis vinifera or that could be implemented by breeding.

Material and methods – Two critical grape development stages were characterized comparing 33 genotypes, including 12 wine grape varieties and 21 microvine lines. Berry softening and growth were precisely monitored to target the onset of ripening and physiological ripening. Main primary metabolites and cations were analysed in order to assess the genotypic differences in fruit sugars/organic balance and titratable acidity.

Results – The phenotypic diversity observed in this study was higher than initially expected. In the mature stage, the weight of the berries varied from 1.04 to 5.25 g and the sugar concentration from 751 to 1353 mmol.L-1. The organic acid composition varied both in concentration (from 80 to 250 meq.L-1) and in composition with a malate / tartrate ratio of between 0.13 to 3.62. A correlation between this ratio and the weight of berries was found. Moreover, a great diversity of cation content has been observed. The potassium content, which is the major cation in the grape, varied between 28 and 57 mmol.L-1 at physiological maturity. This combined with variations in organic acid contents, led to a range of titration acidity from 38 to 215 meq.L-1. This experiment showed that the phenotypic diversity already present in V. vinifera varieties or to be obtained by crossing opens up new perspectives for mitigating the effects of climate change on the composition of berries, notably the rise in temperature.

DOI:

Publication date: September 28, 2023

Issue: GiESCO 2019

Type: Poster

Authors

Antoine BIGARD1,2, Charles ROMIEU1, Dargie T. BERHE2,3, Yannick SIRE2, Cécile MARCHAL4, Sandrine DEDET4, Hernán OJEDA2,4 et Laurent TORREGROSA1,2*

AGAP, Montpellier University, CIRAD, INRA, Montpellier SupAgro, Montpellier, France
UE of Pech Rouge, Montpellier University, INRA, Gruissan, France
Dilla University, SNNPRS, Dilla, Ethiopie
GBRC of Vassal, University of Montpellier, INRA, Montpellier SupAgro, Marseillan, France

Contact the author

Keywords

grapevine, climate changes, warming, breeding, grape composition, sugar/acidity balance

Tags

Citation

Related articles…

Terroir analysis and its complexity

Terroir is not only a geographical site, but it is a more complex concept able to express the “collective knowledge of the interactions” between the environment and the vines mediated through human action and “providing distinctive characteristics” to the final product (OIV 2010). It is often treated and accepted as a “black box”, in which the relationships between wine and its origin have not been clearly explained. Nevertheless, it is well known that terroir expression is strongly dependent on the physical environment, and in particular on the interaction between soil-plant and atmosphere system, which influences the grapevine responses, grapes composition and wine quality. The Terroir studying and mapping are based on viticultural zoning procedures, obtained with different levels of know-how, at different spatial and temporal scales, empiricism and complexity in the description of involved bio-physical processes, and integrating or not the multidisciplinary nature of the terroir. The scientific understanding of the mechanisms ruling both the vineyard variability and the quality of grapes is one of the most important scientific focuses of terroir research. In fact, this know-how is crucial for supporting the analysis of climate change impacts on terroir resilience, identifying new promised lands for viticulture, and driving vineyard management toward a target oenological goal. In this contribution, an overview of the last findings in terroir studies and approaches will be shown with special attention to the terroir resilience analysis to climate change, facing the use and abuse of terroir concept and new technology able to support it and identifying the terroir zones.

Legacy of land-cover changes on soil erosion and microbiology in Burgundian vineyards

Soils in vineyards are recognized as complex agrosystems whose characteristics reflect complex interactions between natural factors (lithology, climate, slope, biodiversity) and human activities. To date, most of the unknown lies in an incomplete understanding of soil ecosystems, and specifically in the microbial biodiversity even though soil microbiota is involved in many key functions, such as nutrient cycling and carbon sequestration. Soil biological properties are indicative of soil quality. Therefore, understanding how soil communities are related to soil ecosystem functioning is becoming an essential issue for soil strategy conservation. Here, we propose to assess the importance of land-cover history on the present-day microbiological and physico-chemical properties. The studied area was selected in the Burgundian vineyards (Pernand-Vergelesses, Burgundy, France) where land occupation has been reconstructed over the last 40 years. Soil samples were collected in five areas reflecting various land cover history (forest, vineyards, shifting from forest to vineyards). For each area, physico-chemical parameters (pH, C, N, P, grain size) were measured and DNA was extracted to characterize the abundance and diversity of microbial communities. The obtained results show significant differences in the five areas suggesting that present-day microbial molecular biomass and bacterial taxonomic is partly inherited from past land occupation. Over longer period of time, such study of land-uses legacies may help to better assess ecosystem recovery and the impact of management practices for a better soil quality and vineyards sustainability.

Climate change projections to support the transition to climate-smart viticulture

The Earth’s system is undergoing major changes through a wide range of spatial and temporal scales as a response to growing anthropogenic radiative forcing, which is pushing the whole system far beyond its natural variability. Sources of greenhouse gases largely exceed their sinks, thus leading to a strengthened greenhouse effect. More energy is thereby being supplied to the system, with inevitable shifts in climatic patterns and weather regimes. Over the last decades, these modifications have been manifested in the full statistical distributions of the atmospheric variables, with dramatic changes in the frequency and intensity of extremes. Natural hazards, such as severe droughts, floods, forest fires, or heatwaves, are being triggered by extreme atmospheric events worldwide, thus threatening human activities. Viticultculture is not only exposed to changing climates but is also highly vulnerable, as grapevine phenology and physiological development are strongly controlled by atmospheric conditions. Therefore, the assessment of climate change projections for a given region is critical for climate change adaptation and risk reduction in viticulture. By adopting timely and suitable measures, the future sustainability and resiliency of the sector can be fostered. Climate-grapevine chain modelling is an essential tool for better planning and management. However, the accuracy of the resulting projections is limited by many uncertainties that must be duly taken into account when transferring knowledge to stakeholders and decision-makers. Climate-smart viticulture will comprise ensembles of locally tuned strategies, envisioning both adaptation and mitigation, assisted by emerging technologies and decision-support systems.

Mesoclimate impact on Tannat in the Atlantic terroir of Uruguay

The study of climate is relevant as an element conditioning the typicity of a product, its quality and sustainability over the years. The grapevine development and growth and the final grape and wine composition are closely related to temperature, while climate components vary at mesoscale according to topography and/or proximity to large bodies of water. The objective of this work is to assess the mesoclimate of the Atlantic region of Uruguay and to determine the effect of topography and the ocean on temperature and consequently on Tannat grapevine behavior.

The concept of terroir: what place for microbiota?

Microbes play key roles on crop nutrient availability via biogeochemical cycles, rhizosphere interactions with roots as well as on plant growth and health. Recent advances in technologies, such as High Throughput Sequencing Techniques, allowed to gain deeper insight on the structure of bacterial and fungal communities associated with soil, rhizosphere and plant phyllosphere. Over the past 10 years, numerous scientific studies have been carried out on the microbial component of the vineyard. Whether the soil or grape compartments have been taken into account, many studies agree on the evidence of regional delineations of microbial communities, that may contribute to regional wine characteristics and typicity. Some authors proposed the term “microbial terroir” including “yeast terroir” for grapes to describe the connection between microbial biogeography and regional wine characteristics. Many factors are involved in terroir including climate, soil, cultivar and human practices as well as their interactions. Studies considering “microbial terroir” greatly contributed to improve our knowledge on factors that shape the vineyard microbial structure and diversity. However, the potential impact of “microbial terroir” on wine composition has yet not received strong scientific evidence and many questions remain to be addressed, related to the functional characterization of the microbial community and its impact on plant physiology and grape composition, the origins and interannual stability of vineyard microbiota, as well as their impact on wine sensorial attributes. The presentation will give an overview on the role of microbiota as a terroir component and will highlight future perspectives and challenges on this key subject for the wine industry.