Vine grape potential byvanleeuwen

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<p> 1. FACTORS DETERMING GRAPEPOTENTIAL AND THEIR CONTROL Professor Cornelis van Leeuwen ENITA Bordeaux Agricultural University Van Leeuwen, 2004, Grapes, wine and environment, Roanoke (Virginia) 2. Plan Definition of grape potential Factors determing grape potential : Absence of grape diseases Vine vigor Berry weight Leaf / fruit weight ratio Terroir: effects of climate, soil and grapevine variety Role of vine water status Examples of grape potential management in variousconditions of soil and climate Van Leeuwen, 2004, Grapes, wine and environment, Roanoke (Virginia) 3. How can grape potential be defined? A grape with a high enological potential : Is healthy Contains an optimum amount of sugar (variable depending on the type of wine) Contains an optimum acidity (variable depending on the type of wine) Presents a good ability to ferment Ideal grape composition is highly variable depending on wine type and color Van Leeuwen, 2004, Grapes, wine and environment, Roanoke (Virginia) 4. Grape potential for the production of high quality red wine+ Small berries+ High phenolic content in the skins (tannins,anthocyanin)+ Phenolic ripeness+ Ripe pips+ Varietal aromas- Vegetatif aromas under the perception treshold- Low malic acid content 2004, Grapes, wine and Van Leeuwen, environment, Roanoke (Virginia) 5. Grape potential for the production of high quality white wine+ Optimum acidity (variable depending on climatic zone)+ Fruity aromas+ High glutathione content- Vegetatif aromas under the perception treshold- Low phenolic content in the skins Van Leeuwen, 2004, Grapes, wine and environment, Roanoke (Virginia) 6. High potential grapes are healthy Van Leeuwen, 2004, Grapes, wine and environment, Roanoke (Virginia) 7. It is not possible to make good wines with disease affected grapes Van Leeuwen, 2004, Grapes, wine and environment, Roanoke (Virginia) 8. Effects of vine vigor on grape potential Van Leeuwen, 2004, Grapes, wine and environment, Roanoke (Virginia) 9. Vine vigor can be highly variable from one plot to anotherMedium to high vigor Medium to low vigor Very low vigor Merlot / 420A, plantation 1984-86, densit 4348 (AOC Buzet) Van Leeuwen, 2004, Grapes, wine and environment, Roanoke (Virginia) 10. How can vine vigor be estimated? Individual vigor of a vine Number and diameter of shoots Secondary leaf area / primary leaf area ratio Vigor of a plot of vines Pruning weight (kg/ha) Van Leeuwen, 2004, Grapes, wine and environment, Roanoke (Virginia) 11. Excessive vigor Delays shoot growth cessation Competition for carbohydrates between grapes and shoots Great development of laterals and suckers Competition apex / grapes Dense canopy Negative canopy micro climate implications: temperature (lower malic acid degradation) low light (less anthocyanin, more IBMP) humidity (diseases) Increases berry Van Leeuwen, 2004, Grapes, wine and weight environment, Roanoke (Virginia) 12. Which parameters determine vine vigor ? Van Leeuwen, 2004, Grapes, wine and environment, Roanoke (Virginia) 13. Effect of environmental ressources on vine vigorApparent photosynthesis (mol CO2 . m- . s-1 Soil (especially soil depth) Mineral elements (N, K, pH) water (water holding capacity) Climate (effect on photosynthesis) temperature light water (rainfall and ETo) Leaf temperature (C) Van Leeuwen, 2004, Grapes, wine and (in : Zufferey, 2000) environment, Roanoke (Virginia) 14. Effect of plant material on vine vigor Rootstock Highly dominant effect 1 2 3 4 5Riparia 101-14 Mgt Gravesac SO 4 ; 1103 P ;Gloire de (-) ; (-) ; 41 B ; 110 R 5 BB ;Montpellier 3309 C ; Fercal 140 Ru ; 420 A ; 161- 99 R 49 C Grapevine variety difficult to use Clone interesting aspect, Van Leeuwen, 2004, Grapes, wine and insufficiently used environment, Roanoke (Virginia) 15. Effect of training system on vine vigor Training system 80 determines exposed 75 h = 1.2m leaf area 70 h = 1m Light interception Crop evapo-transpiration% intercepted 65 radiation 60 (ETC) 55 Wich parameters 50 determine exposed leaf 45 area ? 40 1 1.2 1.4 1.6 1.8 2 2.2 Foliage height Density and particularly Row spacing (m) row spacing Van Leeuwen, 2004, Grapes, wine and environment, Roanoke (Virginia) 16. Effect of berry weight on grape potential Van Leeuwen, 2004, Grapes, wine and environment, Roanoke (Virginia) 17. Relationship berry weight / grape potential 70 y = -2,7084x + 113,09 Small berries containWeight of 50 berries (g) 2 65 R = 0,7157 higher sugar levels 60 55 Small berries have 50 higher concentrations 45 in phenolics 40 18 19 20 21 22 23 Brix Van Leeuwen, 2004, Grapes, wine and environment, Roanoke (Virginia) 18. Which parameters determine berry weight? Berry weight (g) Genetic potential 2,00 (grapevine variety, clone) 1,80 Number of seeds 1,60 Vine water status 1,40 Vine nitrogen status y = -0,2167x - 3,5687 1,20 R = -0,83 1,00 -25 -24 -23 -22 -21 Carbon isotope discrimination (deltaC13) Measured on grape sugar at ripeness Van Leeuwen, 2004, Grapes, wine and(in : Trgoat et al., 2003) environment, Roanoke (Virginia) 19. Effect of leaf area / fruit weight ratio on grape potential Van Leeuwen, 2004, Grapes, wine and environment, Roanoke (Virginia) 20. Van Leeuwen, 2004, Grapes, wine and environment, Roanoke (Virginia) 21. Which parameters determine leaf area / fruit weight ratio? Leaf area limited by Training system water ressources nitrogen ressources Fruit load Fertility (cultivar, vigor) Number of budds / ha Number of berries / cluster Berry weight(in : Huglin, 1958) Van Leeuwen, 2004, Grapes, wine and environment, Roanoke (Virginia) 22. The terroir effect on grape potential Van Leeuwen, 2004, Grapes, wine and environment, Roanoke (Virginia) 23. The terroir effect combines many factors Environmental factors Soil (type, depth) Climate (temperatures, rainfall, sunshine hours) Topography (altitude, slope, exposition) Biological factors Grapevine variety Rootstock Vine age Human factors Viticultural and enological practices Historical factors Economical factors Van Leeuwen, 2004, Grapes, wine and environment, Roanoke (Virginia) 24. All these factors interact It is not possible to define the ideal climate for vine growing Great wines are produced on various soil types Terroir can be defined as an ecosystem, managed by man, in which the vine interacts with environmental factors (soil, climate) Van Leeuwen, 2004, Grapes, wine and environment, Roanoke (Virginia) 25. Hierarchy of factors in the terroir effect Climate, soil and grapevine variety play a major role in the terroir effect What is the hierarchy between these three factors? Van Leeuwen, 2004, Grapes, wine and environment, Roanoke (Virginia) 26. Experimental set-up Three red grapevine varieties: Cabernet-Sauvignon, Cabernet franc and Merlot Planted on three soils: Sand, Gravel and heavy Clay Where studied during eight vintages (variations in climate) 37 variables were registered 3 factor analyses of variance were carried out to compare the role of climate, soil and cultivar in the terroir effect Van Leeuwen, 2004, Grapes, wine and environment, Roanoke (Virginia) 27. The soilsVan Leeuwen, 2004, Grapes, wine and environment, Roanoke (Virginia) 28. Eight vintages with specific climatic conditions 1996: Temperatures and rainfall in Saint-Emilion; 1997 comparison with mean values 200 25 200 25 180 180 160 20 160 20 140...</p>