GiESCO 2015 – Session 2: Climate, territory

In warm climatic conditions, the red sugar concentrations of red varieties reach more than sufficient levels for obtaining high quality wines, but this is often not the case with colour. This relative stability of sugars compared to the sensitivity of anthocyanins to temperature is due to the different temperature ranges for optimal activity of the enzymes producing sugars (18 to 33º C) and pigments (17 to 26º C). Temperatures above 30º C can inhibit the formation of anthocyanins. This trend toward increasing temperature due to climate warming, emphasizes the decoupling between anthocyanins and sugars and produce very alcoholic wines.

Great variations in climatic conditions exist within wine growing areas, as a result of geomorphology, land cover, proximity of main water bodies and urban areas. This means that climate change (CC) will not have the same impact on various locations within a wine growing area.

Grape and wine production, an important economic activity in Portugal, is strongly affected by weather and climate and thus highly vulnerable to climate change. Increased risk of drought, especially in the Mediterranean region, northward shift of isotherms for killing winter frost and prolonged warmer growing seasons are expected to continue throughout the twenty-first century and are of relevance for viticulture.

Within consideration of climate change, it is essential to understand the influence of year to year climate variability and its impact on quantity and composition of grapes, in order to take appropriate decisions for a sustainable viticulture. Climate variability at a regional scale was analyzed for the period 1972 -2014, while its influence on grape yield and composition was studied during the period 1993 – 2014. Measurements were made on 30 plants selected at random in a Tannat vineyard trained on a VSP trellis system.

The temperatures have a major role on the behavior of the vineyards because they directly influence the phenology of the vineyards as well as the characteristics of the grapes, such as the rate of potential sugar. They are a key element of the differentiation of the wine-making-countries soils.

The systemic analysis of the performance of a vineyard at the scale of a wine-making exploitation is made possible by the use of sensors stemming from so called precision techniques, which allow precise and exhaustive geo-located measures. The aim of our study is to exploit this kind of data and evaluate their information using geographical information systems (GIS) and crossing different layers representing characteristic and independent variables of the production system.

Burgundy terroirs are famous worldwide but have never been described from an ecophysiological point of view. To better understand plant-environment relations in these terroirs 8 grapevine plots were monitored during two vintages (2011-2013), on Corton Hill, Burgundy, France.

While evapotranspiration (ET) and crop coefficient (Kc) information for wine grapes grown on flat terrain are widely published, there is little information available on ET and Kc for vines grown on slopes and even less on the impact of water stress on vine ET. Therefore, our objective was to measure ET and stem water potential (SWP) in pilot studies conducted on North and South facing sloped vineyards to evaluate differences in vine water use to improve irrigation management on the basis of vineyard topography.

Ribeira Sacra is a Spanish DO located in Galicia (NW of Spain). Mencía is the most important red grape grown in the region. Most vineyards in the region are terraced due to the steep slopes that characterize the region. The aim of this research was to perform the effect of vintage, elevation and exposition on the YAN (Yeast Assimilable Nitrogen) and amino acid profile in Mencía grapes.

Trans-resveratrol is a non-flavonoid phenolic compound produced by a limited number of plant species that has a wide range of nutraceutical effects. Grapevine is the one most important potential sources of trans-resveratrol and accumulates it in response to pathogens and herbivores, exposure to UVB, UVC and different elicitors as methyl jasmonic acid and salicylic acid.

Grapes are temperate crops and are most frequently damaged by freezing temperatures. The severe economic losses that result from the freezing injury continue to be a major constraint to the growth of the grape and wine industries in cold regions.

In Spain, Grenache is the second most planted red wine grape variety. In warm years with high temperatures during ripening grape composition could be modified, thus phenolic synthesis damaged. In order to evaluate the behavior of Grenache, two vineyards were chosen in Tarragona (T) and Priorat (P) AOC.

In the framework of a French network of researchers working on the phenology of forest trees, fruit trees and grapevine (PERPHECLIM ACCAF project), methods of observations and sampling strategies were discussed and compared. The objective was a harmonisation of data acquisition strategies for grapevine phenology.

Ribeira Sacra AOC (NW Spain) is characterized by high slopes and the vine growing in terraces. Along this AOC it exist different areas with different elevation, exposure and temperature conditions (Amandi, Chantada, Quiroga-Bibei, Ribeiras do Sil and Ribeiras do Miño). Mencía (Vitis vinifera L.) is the most important red grape cultivar in this geographic area. Anthocyanins are a class of pigmented phenolic compounds responsible for the red color of grapes and wine and it can be influenced by environmental factors.

With global warming, vitiviniculture has been spreading towards the poles. It also gains the tropics, probably because of the growth of economical powers such as Brazil and India and also thanks to significant agronomic progresses made since the middle of the 20th century.