The three main components of terroir—soil, climate, and cultivar—were studied simultaneously. Vine development and berry composition of nonirrigated Vitis vinifera L. cv. Merlot, Cabernet franc, and Cabernet Sauvignon were compared on a gravelly soil, a soil with a heavy clay subsoil, and a sandy soil with a water table within the reach of the roots. The influence of climate was assessed with year-to-year variations of maximum and minimum temperatures, degree days (base of 10°C), sunshine hours, ETo, rainfall, and water balance for the period 1996 to 2000. The effects of climate, soil, and cultivar were found to be highly significant with regard to vine behavior and berry composition (an example being anthocyanin concentration). The impacts of climate and soil were greater than that of cultivar. Many of the variables correlated with the intensity of vine water stress. It is likely that the effects of climate and soil on fruit quality are mediated through their influence on vine water status.

http://www.oliviertregoat.com/influence_of_climate_soil_cultivar.pdf

Influence of Climate, Soil, and Cultivar on Terroir

Grapevine (Vitis vinifera L.) is a non-climacteric fruit species used as table fruit, dried raisins, and for vinification (wines) and distillation (liquors). In recent years, our knowledge of the molecular basis of ripening regulation has improved. Water status, light conditions, and temperature may hasten, delay, or enhance ripening. Hormones seem to play a central role, as their concentrations change prior to and during ripening and in response to several environmental cues. The review summarizes recent data related to the molecular and hormonal control of grape berry development and ripening, with special emphasis on secondary metabolism and its response to the environment, and pinpoints some experimental limitations.

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Berry ripening: recently heard through the grapevine

Iron (Fe) deficiency-induced chlorosis is a major nutritional disorder in crops growing in calcareous soils. Iron deficiency in fruit tree crops causes chlorosis, decreases in vegetative growth and marked fruit yield and quality losses. Therefore, Fe fertilizers, either applied to the soil or delivered to the foliage, are used every year to control Fe deficiency in these crops. On the other hand, a substantial body of knowledge is available on the fundamentals of Fe uptake, long and short distance Fe transport and subcellular Fe allocation in plants. Most of this basic knowledge, however, applies only to Fe deficiency, with studies involving Fe fertilization (i.e., with Fe-deficient plants resupplied with Fe) being still scarce. This paper reviews recent developments in Fe-fertilizer research and the state-of-the-art of the knowledge on Fe acquisition, transport and utilization in plants. Also, the effects of Fe-fertilization on the plant responses to Fe deficiency are reviewed. Agronomical Fe-fertilization practices should benefit from the basic knowledge on plant Fe homeostasis already available; this should be considered as a long-term goal that can optimize fertilizer inputs, reduce grower's costs and minimize the environmental impact of fertilization.

Towards a knowledge-based correction of iron chlorosis

Viticulture and winemaking are important socioeconomic sectors in many European regions. Climate plays a vital role in the terroir of a given wine region, as it strongly controls canopy microclimate, vine growth, vine physiology, yield, and berry composition, which together determine wine attributes and typicity. New challenges are, however, predicted to arise from climate change, as grapevine cultivation is deeply dependent on weather and climate conditions. Changes in viticultural suitability over the last decades, for viticulture in general or the use of specific varieties, have already been reported for many wine regions. Despite spatially heterogeneous impacts, climate change is anticipated to exacerbate these recent trends on suitability for wine production. These shifts may reshape the geographical distribution of wine regions, while wine typicity may also be threatened in most cases. Changing climates will thereby urge for the implementation of timely, suitable, and cost-effective adaptation strategies, which should also be thoroughly planned and tuned to local conditions for an effective risk reduction. Although the potential of the different adaptation options is not yet fully investigated, deserving further research activities, their adoption will be of utmost relevance to maintain the socioeconomic and environmental sustainability of the highly valued viticulture and winemaking sector in Europe.

A Review of the Potential Climate Change Impacts and Adaptation Options for European Viticulture

Climate change will impose increasingly warm and dry conditions on vineyards. Wine quality and yield are strongly influenced by climatic conditions and depend on complex interactions between temperatures, water availability, plant material, and viticultural techniques. In established winegrowing regions, growers have optimized yield and quality by choosing plant material and viticultural techniques according to local climatic conditions, but as the climate changes, these will need to be adjusted. Adaptations to higher temperatures include changing plant material (e.g., rootstocks, cultivars and clones) and modifying viticultural techniques (e.g., changing trunk height, leaf area to fruit weight ratio, timing of pruning) such that harvest dates are maintained in the optimal period at the end of September or early October in the Northern Hemisphere. Vineyards can be made more resilient to drought by planting drought resistant plant material, modifying training systems (e.g., goblet bush vines, or trellised vineyards at wider row spacing), or selecting soils with greater soil water holding capacity. While most vineyards in Europe are currently dry-farmed, irrigation may also be an option to grow sustainable yields under increasingly dry conditions but consideration must be given to associated impacts on water resources and the environment.

https://www.mdpi.com/2073-4395/9/9/514/pdf

An Update on the Impact of Climate Change in Viticulture and Potential Adaptations

Berry fresh weight and composition are under the control of complex interactions among genotype, environmental factors, and viticulture practice, which all affect not only the mean value but also the ranges of variation in berry traits. Both mean values and variation range in berry composition play a role in berry quality and, subsequently, wine typicity. This review examines recent ecophysiological, genetic, and molecular knowledge to provide better understanding of the mechanisms that influence variability in berry weight and composition. We specifically reviewed the variation range in berry weight and composition (including sugars, organic acids, and anthocyanins) among Vitis genotypes, the environmental and viticulture practices that cause variability for a given cultivar, the genetic clues underlying the genotypic variation, and the putative genes controlling berry weight and composition. Despite numerous studies comparing differences in the mean value of a berry trait among different environment conditions and viticulture practices, very few studies have explored the level of variation in response to those factors. Present genetic and molecular studies are mainly focused on identifying genes involved in the control of berry weight and composition, with few considerations of environmental factors that affect their expression. In the future, more effort should be directed toward integration of genetic and molecular work with ecophysiological approaches in an effort to gain novel insights into the cause of variability in grape fresh weight and composition.

/pdf/ecophysiological-genetic-and-molecular-causes-of-variation-mwf8m9fh0x.pdf

Ecophysiological, Genetic, and Molecular Causes of Variation in Grape Berry Weight and Composition: A Review

Rootstocks as a component of adaptation to environment

Grapevines were propagated from cuttings up until the late 19th century when the soil-borne aphid phylloxera (Daktulosphaira vitifoliae [Fitch]) destroyed Vitis vinifera L. vines grown on their own roots. The damaging import of grape phylloxera to France in 1868 led to extensive international research and collaboration to save European viticulture. Numerous growers, breeders and scientists played important roles in the historic campaign against the grape phylloxera and in finding the solution to this problem, which ultimately lay in grafting European vines on American rootstocks. Nowadays, more than 80% of the vineyards worldwide use grafted plants: a scion of V. vinifera grafted onto a rootstock of single American Vitis species or interspecific hybrids of Vitis species that combine desirable features of their parentage. The majority of rootstocks used today were bred at the end of the 19th century or at the turn of the 20th century. They are mainly hybrids of four species: V. berlandieri, V. riparia, V. rupestris and V. vinifera, but secondary species have also been used. In addition to phylloxera, rootstocks contribute to the control of other soil-borne pests such as nematodes and to various abiotic constraints such as drought, salinity, limestone and mineral nutrition problems. They also strongly interact with scion genotypes and modify whole plant development, biomass accumulation and repartition, and phenology. In the context of climate change, they may be considered as a key element of adaptation. Rootstock breeding programs in the main grape growing countries around the world aim to improve pest resistance and adaptation to abiotic stresses. This article will give an overview of the history of rootstock use in the world, a brief description of the main rootstocks cultivated and some details on current breeding programs.

Grapevine rootstocks: origins and perspectives

The performance of the plant canopy analyzer LAI-2000 was evaluated in three seasons to estimate vineyard LAI (leafarea index) in the Bordeaux area. Measurements were made in a vertical-trellised vineyard with 5555 Semillon and Sauvignon blanc vines per ha, and with 2525 lyre-trained Cabernet franc vines per ha. Various LAI-2000 sampling protocols were tested and the data compared with destructive determinations. While the results from single vines a ere not satisfactory, very good relationships were obtained if five consecutive vines were used. In the vertical-trellised vineyard, a very accurate and direct estimate of LAI could be obtained with the LAI-2000 using a combination of "parallel" and "diagonal" sampling protocol. LAI values obtained by direct and LAI-2000 had a 1:1 correspondence and were identical for both, year and cultivar. For the lyre system, a local calibration was required, mainly because of the contribution of shoots, perennial vine parts and posts. This calibration was easily obtained by progressively removing leaves from the vines.

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Evaluation of an indirect method for leaf area index determination in the vineyard: Combined effects of cultivar, year and training system

Muscadine (Muscadinia rotundifolia) is known as a resistance source to many pests and diseases in grapevine. The genetics of its resistance to two major grapevine pests, the phylloxera D. vitifoliae and the dagger nematode X. index, vector of the Grapevine fanleaf virus (GFLV), was investigated in a backcross progeny between the F1 resistant hybrid material VRH8771 (Vitis-Muscadinia) derived from the muscadine R source ‘NC184–4’ and V. vinifera cv. ‘Cabernet-Sauvignon’ (CS). In this pseudo-testcross, parental maps were constructed using simple-sequence repeats markers and single nucleotide polymorphism markers from a GBS approach. For the VRH8771 map, 2271 SNP and 135 SSR markers were assembled, resulting in 19 linkage groups (LG) and an average distance between markers of 0.98 cM. Phylloxera resistance was assessed by monitoring root nodosity number in an in planta experiment and larval development in a root in vitro assay. Nematode resistance was studied using 10–12 month long tests for the selection of durable resistance and rating criteria based on nematode reproduction factor and gall index. A major QTL for phylloxera larval development, explaining more than 70% of the total variance and co-localizing with a QTL for nodosity number, was identified on LG 7 and designated RDV6. Additional QTLs were detected on LG 3 (RDV7) and LG 10 (RDV8), depending on the in planta or in vitro experiments, suggesting that various loci may influence or modulate nodosity formation and larval development. Using a Bulked Segregant Analysis approach and a proportion test, markers clustered in three regions on LG 9, LG 10 and LG 18 were shown to be associated to the nematode resistant phenotype. QTL analysis confirmed the results and QTLs were thus designated respectively XiR2, XiR3 and XiR4, although a LOD-score below the significant threshold value was obtained for the QTL on LG 18. Based on a high-resolution linkage map and a segregating grapevine backcross progeny, the first QTLs for resistance to D. vitifoliae and to X. index were identified from a muscadine source. All together these results open the way to the development of marker-assisted selection in grapevine rootstock breeding programs based on muscadine derived resistance to phylloxera and to X. index in order to delay GFLV transmission.

/pdf/characterization-of-genetic-determinants-of-the-resistance-woamidmokl.pdf

Characterization of genetic determinants of the resistance to phylloxera, Daktulosphaira vitifoliae, and the dagger nematode Xiphinema index from muscadine background

Jean-Pascal Tandonnet

Papers

Ecophysiological, Genetic, and Molecular Causes of Variation in Grape Berry Weight and Composition: A Review

Rootstocks as a component of adaptation to environment

Grapevine rootstocks: origins and perspectives

Evaluation of an indirect method for leaf area index determination in the vineyard: Combined effects of cultivar, year and training system

Characterization of genetic determinants of the resistance to phylloxera, Daktulosphaira vitifoliae, and the dagger nematode Xiphinema index from muscadine background