Viticulture and wine producing are important practices for the economy of several countries in Europe, and also in others continents. Despite its importance, global wine production decreased 6% in 2012 to 252 million hectolitres (Figure 1; Organization of Vine and Wine, OIV, 2013).
Figure 1. Global wine production 2000-2012, source OIV
This was partially due to a lower harvest in Europe during lasts years but also a longer term trend. France, Italy, and Spain are still the biggest producers, while it is worth noticing that China, Chile, and New Zealand recorded the largest increases in production over the last years. In spite of the downward trend in vine surface area, grape production underwent an upward trend over the last few years (Fraga et al., 2012).
Viticulture and winemaking are influenced by a large number of factors, among which climate, soils, and grown varieties/genotypes are the most important (Fraga et al., 2012). Climate is a key factor in the present viticulture (Figure 2). Grapevine physiological change, together with grape berry development and ripening, are high related to the clime. As showed in Figure 2, the inception and the duration of each phenological stages is mostly related to environmental conditions (Jones and Davis, 2000).
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Figure 2. Vegetative and reproductive cycles and vine phenological stages. Modified from Fraga et al. (2013)
The duration of the growing season of a particular cultivar is affected, together with the climate which strongly influences the development of this crop and the yield and wine quality, also by the combination of these factors: soil moisture, air temperature, and crop- management practices (Webb et al., 2012). Within this context, climate changes is the most important factor in which the viticulture have to cope with (Hannah et al., 2013). As described in the first chapter of this thesis, breeding of new grapevine genotypes, which can better deal with the environmental changes, is essential for Italian and European viticulture. Indeed, development of new grapevine rootstocks with an higher tolerance to environmental stresses, drought in particular, should be a successful strategy to overcome climate limitations (Hannah et al., 2013) and maintain the traditional Mediterranean grapevine growing area. This strategy have several advantages compared to the breeding programs associate to grape cultivar, mainly related to the handiness to confer desired carachteristic (e.g. drought tolerance) to the vine. Taking into account results presented in this thesis and in another work (Meggio et al., IN PRESS), M4 rootstock well comply with this requisite. Indeed it showed an higher resistance to drought in comparison to 101.14 susceptible genotype, acting different strategies related to the regulation of different metabolism and pathways (e.g. plant hormones, sugars, flavonoids and
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stilbenes). In addition to their capability to overcome climate limitations, grapevine rootstocks greatly influenced grapevine reproductive performances (Koundouras et al., 2008; Kidman et al., 2013) fruit development, ripening and quality (Walker et al., 2002, 2004). So, together with the induction of an higher tolerance to environmental disturbance to the scion, viticulture need new rootstocks which did not alter quality of grape berry and wine or, better, which increase their qualitative characteristics.
The second part of this thesis showed that M4, in addition to the higher tolerance to drought, did not significantly alter grape berry quality of Cabernet sauvignon cultivar. Indeed, it was showed that it cause an advance in the onset of ripening in comparison to the 1103P rootstock, which is a more vigorous rootstock (Gambetta et al., 2012). Within this background, M4 not only enhance water stress tolerance, but also positively influenced grape berry development and ripening throughout the control of different metabolism, among which auxins seem to play a pivotal role.
So, considering new scenario for the European and Italian vine growing and the climate changes which can alter quality of grape berries and wine on a global scale, development of new rootstocks with desirable traits, together with those belonging to the “M series”, it will be one of the main goal of the future viticulture.
References
Fraga H, Malheiro AC, Moutinho-Pereira J, Santos JA. 2012. An overview of climate change impacts on European viticulture. Food and Energy Security 1, 94-110.
Gambetta GA, Manuck CM, Drucker ST, Shaghasi T, Fort K, Matthews MA, Walker MA, McElrone AJ. 2012. The relationship between root hydraulics and scion vigour across Vitis rootstocks: what role do root aquaporins play? Journal of experimental botany 63, 6445-6455.
Hannah L, Roehrdanz PR, Ikegami M, Shepard AV, Shaw MR, Tabor G, Zhi L, Marquet PA, Hijmans RJ. 2013. Climate change, wine, and conservation. Proceedings of the National Academy of Sciences of the United States of America 110, 6907-6912. Jones GV, Davis RE. 2000. Climate Influences on Grapevine Phenology, Grape Composition, and Wine Production and Quality for Bordeaux, France. American Journal of Enology and Viticulture 51, 249-261.
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Kidman CM, Dry PR, McCarthy MG, Collins C. 2013. Reproductive performance of Cabernet Sauvignon and Merlot (Vitis vinifera L.) is affected when grafted to rootstocks. Australian Journal of Grape and Wine Research 19, 409-421.
Koundouras S, Tsialtas IT, Zioziou E, Nikolaou N. 2008. Rootstock effects on the adaptive strategies of grapevine (Vitis vinifera L. cv. Cabernet–Sauvignon) under contrasting water status: Leaf physiological and structural responses. Agriculture, Ecosystems & Environment 128, 86-96.
Meggio F, Prinsi B, Negri, A.S. , Di Lorenzo GS, Lucchini G, Pitacco P, Failla O, Scienza A, Cocucci C, Espen L. IN PRESS. Different biochemical and physiological responses of two grapevine rootstock genotypes to drought and salt treatments. Australian Journal of Grape and Wine Research.
Walker RR, Blackmore DH, Clingeleffer PR, Correll RL. 2002. Rootstock effects on salt tolerance of irrigated field-grown grapevines (Vitis vinifera L. cv. Sultana).: 1. Yield and vigour inter-relationships. Australian Journal of Grape and Wine Research 8, 3-14. Walker RR, Blackmore DH, Clingeleffer PR, Correll RL. 2004. Rootstock effects on salt tolerance of irrigated field-grown grapevines (Vitis vinifera L. cv. Sultana) 2. Ion concentrations in leaves and juice. Australian Journal of Grape and Wine Research 10, 90-99.
Webb LB, Whetton PH, Bhend J, Darbyshire R, Briggs PR, Barlow EWR. 2012. Earlier wine-grape ripening driven by climatic warming and drying and management practices. Nature Clim. Change 2, 259-264.
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