Cornelis van Leeuwen

Rootstock control of scion transpiration and its acclimation to water deficit are controlled by different genes.

The stomatal control of transpiration is one of the major strategies by which plants cope with water stress. Here, we investigated the genetic architecture of the rootstock control of scion transpiration-related traits over a period of 3 yr. The rootstocks studied were full sibs from a controlled interspecific cross (Vitis vinifera cv. Cabernet Sauvignon × Vitis riparia cv. Gloire de Montpellier), onto which we grafted a single scion genotype. After 10 d without stress, the water supply was progressively limited over a period of 10 d, and a stable water deficit was then applied for 15 d. Transpiration rate was estimated daily and a mathematical curve was fitted to its response to water deficit intensity. We also determined δ(13) C values in leaves, transpiration efficiency and water extraction capacity. These traits were then analysed in a multienvironment (year and water status) quantitative trait locus (QTL) analysis. Quantitative trait loci, independent of year and water status, were detected for each trait. One genomic region was specifically implicated in the acclimation of scion transpiration induced by the rootstock. The QTLs identified colocalized with genes involved in water deficit responses, such as those relating to ABA and hydraulic regulation. Scion transpiration rate and its acclimation to water deficit are thus controlled genetically by the rootstock, through different genetic architectures.

Why climate change will not dramatically decrease viticultural suitability in main wine-producing areas by 2050

Hannah et al. (1) recently published a comprehensive study showing substantial impacts of climate change on viticultural suitability, leading to potential ecological issues. We agree that expansion of viticulture into new areas can lead to a decrease in biodiversity and that an increase in water use for irrigation might lead to major freshwater conservation impacts. However, we disagree with the alarming statement that suitability for winegrowing of main wine-producing areas worldwide will dramatically decrease over the next 40 y. We point out major methodological flaws in ref. 1, mostly linked to (i) the misuse of bibliographical data to compute suitability index, (ii) underestimation of adaptations of viticulture to warmer conditions, and (iii) the inadequacy of the monthly time step in the …

Impact of soil texture and water availability on the hydraulic control of plant and grape-berry development

AimsAll components of the soil-plant-atmosphere (s-p-a) continuum are known to control berry quality in grapevine (Vitis vinifera L.) via ecophysiological interactions between water uptake by roots and water loss by leaves. The scope of the present work was to explore how the main hydraulic components of grapevine influence fruit quality through changes in liquid- and gas-phase hydraulic conductance.MethodsTo reach our objectives, determinations of shoot growth, berry size and sugar content, leaf gas exchange, predawn leaf water potential (as a proxy of soil water potential), midday stem water potential and leaf water potential were performed in conjunction with anatomical measurements of shoot xylem. All measurements were conducted in two different cultivars (Cabernet franc and Merlot) and on three different soil types (clayey, gravelly, and sandy).ResultsShoot xylem morphometric characteristics and whole-plant hydraulic conductance were influenced by cultivar and soil type. Differences in leaf gas exchange parameters and water potentials were determined by soil type significantly more than by cultivar. Between the two extremes (gravelly soil imposing drought conditions and sandy soil with easily accessible water) the clayey soil expressed an intermediate plant water consumption and highest sugar accumulation in berry.ConclusionsHydraulic and non hydraulic limitations to vine/berry interactions supported the conclusion that water availability in the soil overrides differences due to cultivar in determining the productive potential of the vineyard. Non hydraulic stomatal control was expected to be an important component on plants grown on the clayey soil, which experienced a moderate water stress. Possible links between hydraulic traits and berry development and quality are discussed.

Impact of clonal variability in Vitis vinifera cabernet franc on grape composition, wine quality, leaf blade stilbene content, and downy mildew resistance

In this study, 10 clones of Vitis vinifera Cabernet franc (not yet commercial) have been phenotyped on precocity, grape composition, and assessment of wine quality made by microvinification in 2008-2010. Additionally, two original criteria have been considered: concentration of 3-isobutyl-2-methoxypyrazine (IBMP) in grapes and wines (the green bell pepper flavor) and resistance of grapevines to downy mildew ( Plasmopara viticola ) by stilbene quantification upon infection. Precocity of veraison varied up to four days at veraison. Berry size and yield were highly variable among clones. However, these variables were not correlated. Tanins and anthocyanins varied among clones in grapes and wines. Variations in grape and wine IBMP were not significant. Some clones showed lower susceptibility for downy mildew on leaves. Lower susceptibility was linked to a higher production of stilbenic phytoalexins involved in downy mildew resistance mechanisms.

Comparison of Three Operational Tools for the Assessment of Vine Water Status: Stem Water Potential, Carbon Isotope Discrimination Measured on Grape Sugar and Water Balance

Yield, grape composition and wine sensory attributes tightly depend on vine water status. Hence, the measurement of vine water uptake is important for research purposes as well as for practical vineyard management. Many techniques have been developed over the past decades. Among them, three are of particular interest, because they are easy to implement, robust and because their utilization is complementary: stem water potential , carbon isotope discrimination measured on grape sugar and water balance. The present chapter describes and compares these three methods . It also indicates in which situation each of them will be most useful for researchers and vineyard managers.

Sensitivity of Grapevine Phenology to Water Availability, Temperature and CO2 Concentration

In recent decades, mean global temperatures have increased in parallel with a sharp rise in atmospheric carbon dioxide (CO2) levels, with apparent implications for precipitation patterns. The aim of the present work is to assess the sensitivity of different phenological stages of grapevine to temperature and to study the influence of other factors related to climate change (water availability and CO2 concentration) on this relationship. Grapevine phenological records from 9 plantings between 42.75°N and 46.03°N consisting of dates for budburst, flowering and fruit maturity were used. In addition, we used phenological data collected from two years of experiments with grapevine fruit-bearing cuttings with two grapevine varieties under two levels of water availability, two temperature regimes and two levels of CO2. Dormancy breaking and flowering were strongly dependent on spring temperature, while neither variation in temperature during the chilling period nor precipitation significantly affected budburst date. The time needed to reach fruit maturity diminished with increasing temperature and decreasing precipitation. Experiments under semi-controlled conditions revealed great sensitivity of berry development to both temperature and CO2. Water availability had significant interactions with both temperature and CO2; however, in general, water deficit delayed maturity when combined with other factors. Sensitivities to temperature and CO2 varied widely, but higher sensitivities appeared in the coolest year, particularly for the late ripening variety, ‘White Tempranillo’. The knowledge gained in whole plant physiology and multi stress approaches is crucial to predict the effects of climate change and to design mitigation and adaptation strategies allowing viticulture to cope with climate change.

Influence of plot characteristics and surrounding vegetation on the intra-plot spatial distribution of Empoasca vitis.

1 Spatial distributions of adults and nymphs of Empoasca vitis were assessed during 3 years inside two adjacent vine plots having considerable intra‐plot variability, diversified natural ground cover and surrounding vegetation, and no insecticide application. 2 Geostatistical analysis confirmed that, in spite of repeated adult migrations, spatial distributions of summer populations were highly aggregated, similar every year and similar between adults and nymphs. Comparison of insect distribution with intra‐plot characteristics, such as vine plant vigour (leaf density and leaf chlorophyll concentration) and phenology, plot topography and surrounding vegetation, revealed that E. vitis clearly aggregates in areas with the most vigorous vine plants. 3 Even though the presence of natural enemies in the surrounding vegetation was confirmed by specific observations, we did not observe significant population decrease at the contiguous plot edges. Natural ground cover, together with the absence of insecticide, might allow the spreading and perennial conservation of E. vitis natural enemies inside the plots. 4 Clear adult aggregations observed along downwind woodlands suggest that this vegetation acts as a barrier and intercepts the adults flying passively across the plot. However, this surrounding vegetation could also serve as an alternative refuge when vine water deficit and vine foliage temperature increase.

Roostocks/Scion/Nitrogen Interactions Affect Secondary Metabolism in the Grape Berry

The present work investigates the interactions between soil content, rootstock, and scion by focusing on the effects of roostocks and nitrogen supply on grape berry content. Scions of Cabernet Sauvignon (CS) and Pinot Noir (PN) varieties were grafted either on Riparia Gloire de Montpellier (RGM) or 110 Richter (110R) rootstock. The 4 rooststock/scion combinations were fertilized with 3 different levels of nitrogen after fruit set. Both in 2013 and 2014, N supply increased N uptake by the plants, and N content both in vegetative and reproductory organs. Rootstock, variety and year affected berry weight at harvest, while nitrogen did not affect significantly this parameter. Grafting on RGM consistently increased berry weight compared to 110R. PN consistently produced bigger berries than CS. CS berries were heavier in 2014 than in 2013, but the year effect was less marked for PN berries. The berries were collected between veraison and maturity, separated in skin and pulp, and their content was analyzed by conventional analytical procedures and untargeted metabolomics. For anthocyanins, the relative quantitation was fairly comparable with both LC-MS determination and HPLC-DAD, which is a fully quantitative technique. The data show complex responses of the metabolite content (sugars, organic acids, amino acids, anthocyanins, flavonols, flavan-3-ols/procyanidins, stilbenes, hydroxycinnamic, and hydroxybenzoic acids) that depend on the rootstock, the scion, the vintage, the nitrogen level, the berry compartment. This opens a wide range of possibilities to adjust the content of these compounds through the choice of the roostock, variety and nitrogen fertilization.

Mapping Grapevine (Vitis vinifera L.) Water Status during the Season Using Carbon Isotope Ratio (δ13C) as Ancillary Data

Vine water status is a major parameter for vine management because it affects both wine quality and yield. In order to optimize vineyard management and harvesting practices, it is necessary to characterize vineyard water status spatial variability. This work aims at establishing an empirical spatial model for stem water potential (ΨStem) with ancillary data based on vine water status. Carbon isotope ratio (δ13C) measured at harvest was selected as ancillary data because it reflects only the effect of vine water status variations integrated over the season and is not impacted by other factors such as vine nitrogen status. The proposed model was applied at the intrablock level. It is based on the spatial extrapolation of a ΨStem value measured at a reference site using δ13C values collected over the block. Measurements of ΨStem and δ13C were carried out over three consecutive years on 96 locations within the block. ΨStem values obtained with a spatial model were more accurate than ΨStem values obtained with a nonspatial model, indicating the relevancy of δ13C values to account for spatial variability of vine water status. Results show that operational maps of vine water status can be obtained by means of a spatial model, in which δ13C values from a previous season are used as ancillary data. Maps can be updated at any given time during the season by carrying out a limited number of ΨStem measurements in selected locations. This model offers a tool to monitor vine water status and to implement management practices while considering vine water status intrablock variability.

Soils and Terroir Expression in Wines

No other agricultural product has as strong a relationship with the soil as does wine. The link is immediately perceptible in the label, as most wines bear the name of the place of their origin. In a multitude of locations, each with particular characteristics with regard to soil and climate, a myriad of wines are produced, all differing in taste and quality. Some conditions are particularly favourable to wine growing and allow the production of wines of exquisite quality. The market acknowledges these differences in quality and accepts that some wines are worth tenfold, or even hundredfold, the price of those grown in less favourable environments. The hierarchy of wines has become more and more sophisticated over the years, resulting in the delimitation of production areas and the classification of famous growths. The most striking example is found in the Burgundy region, where selling prices vary from one to tenfold depending on the location of the vineyard plot, although viticultural practices and winemaking process are basically identical across plots belonging to the same grower. As a result, value can be attributed to wine production in terms of quality rather than quantity, which is a quite unique situation among agricultural products. In most wine growing areas, productivity is three to five times lower than possible attainable yields. Vines are often grown under environmental stress, which reduces yield but enhances grape quality potential. In wine production, the effect of the environment on wine quality is referred to as “the terroir effect”. Although “terroir” has similarities with the French word “terre”, it has a broader meaning than the influence of the soil on the taste of wine. Terroir is concerned with the relationship between the characteristics of an agricultural product (generally wine) and its geographic origin, which might influence these characteristics. It can be defined as an interactive ecosystem, in a given place, including climate, soil and the