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Grape Biology

Grape Biology. Rebecca Harbut Dept of Horticulture, UW-Madison. Vitaceae. Mostly woody, tree-climbing vines Tendrils and inflorescences opposite the leaves 12 genera within the family Vitis Ampelocissus Clematicissus Parthenocissus (Virginia Creeper) Ampelopsis Cissus (Kangaroo vine).

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Grape Biology

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  1. Grape Biology Rebecca Harbut Dept of Horticulture, UW-Madison

  2. Vitaceae • Mostly woody, tree-climbing vines • Tendrilsand inflorescences opposite the leaves • 12 genera within the family • Vitis • Ampelocissus • Clematicissus • Parthenocissus(Virginia Creeper) • Ampelopsis • Cissus(Kangaroo vine)

  3. Genus Vitis • 60 species of grape • 30 species native to North America • Two subgenera: • Euvitis(38 chromosomes) • Grapes adhere to cluster • Muscadinia(40 chromosomes) • Grapes fall off cluster as they mature

  4. Genus Vitis • Euvitis • Vitisvinifera European wine grapes • Over 5000 cultivars • 90% of world grape production • Vitislabrusca American species, fox grape • VitisripariaAmerican species, ‘cold- climate grapes • French-American hybrids • ‘Marechal Foch', ‘Vidal Blanc', ‘Chambourcin', and ‘Seyval'. • Muscadinia • VitisrotundifoliaMuscadine grapes (grown in SE USA, lack cold hardiness

  5. VitisVinifera Cold tender More upright growth Phloxera susceptible VitisLabrusca & VitisRiparia More cold hardy More trailing growth More vigorous growth European vs. American

  6. Grape Use In U.S. Wine - 50-55%   Raisins - 25-30% Table - 10-15%             Juice, jelly, etc. - 6-9% Canned - < 1%

  7. Grape Anatomy

  8. Roots • Grapes have tap root system • Main tap root with lateral roots • Most absorption (nutrients and water) carried out by root tips and root hairs • Soil conditions are critical (proper soil test and site prep) • Vesicular arbuscularmycorrhizae (VAM) • Most associated with plants in low P soils • Most grapes have VAM infecting roots

  9. Rootstocks • Primary reason - Phylloxera resistance • 3 species used: 1) Vitisrupestris: A native of the eastern United States which provides vigor2) Vitisberlandieri: A native of the dry southwestern United States which provides drought tolerance.3) Vitisriperia: A native of the northeastern United States which provides cool weather tolerance. Photo: OSU

  10. Own Rooted Vs. Rootstocks • Grafted vines can be more expensive • Increased time in nursery • More labor • Own rooted can be better in areas prone to winter damage as new growth can come from established roots • Rootstocks can be used to compensate for less than ideal sites

  11. Root Growth and Irrigation • Root growth is critical for vine establishment • Irrigation during can allow for improved root establishment • Deep watering encourages roots to move down into the soil profile

  12. Trunk • Primary support structure • Important in carbohydrate storage • May be single or split

  13. Canes, Cordons and Shoots…Oh My! • Cordon-permanent stem • Trained horizontally • Not all systems have cordons • Cane • One year old shoot • SPUR- Canes pruned to 2-3 buds • Shoot • Current seasons growth • Bear fruit clusters

  14. One year old cane Shoot Cluster Tendril

  15. Buds Initiation • Primordia- undefined tissue with potential to develop into a defined structure • Primordia can become: tendril, shoot, inflorescence • Temperature, vine vigor, light affect cluster size and number • Primordia initiate when only few inches from growing shoot tip

  16. Buds Differentiation • Differentiation- process in which primordia become committed to develop into a specialized tissue • Tendril, inflorescence, shoot • Secondary buds differentiate later • Important if primary bud is killed

  17. Primary Bud Tertiary Bud Secondary Bud

  18. Tendrils • Specialized lateral branches • Derived from same undifferentiated primordia as flowers • Grow away from the light • Become lignified • Allow plant to invest less in structural trunk • If tendril does not latch onto anything it will wither and die • Tendrils have determinate growth

  19. Flowers • Small 1/8 inch, indiscrete • 5 sepals, petals, stamens • Superior ovary • 2 locules/2 ovules per locule • Cultivated grapes have perfect flowers • Some wild have male and female flowers • Evidence that cross pollination increases size

  20. Fused petals = calyptra

  21. Inflorescence/Cluster • Panicle inflorescence • Inflorescence usually on 3rd or higher node • # of inflorescence (clusters)/shoot varies by: • Management, cultivar, environment • 0 to 5 (or more)

  22. Hardiness • Vinifera • 0 to -10°F bud injury • <-10°F trunk injury • French hybrids • -10°F bud and trunk injury • -20°F kill buds and trunks • American types • -20°F would cause crop reduction

  23. Flowering • Grapes flower long after bud-break • Shoot must develop enough leaves to support fruit development • Flowers open when shoots have 15-17 nodes • Length of flowering period dependent on environment

  24. Pollination • Wind pollinated • Weather dependent • Fertilization dependant on weather • Pollen tube must grow down through style (highly temperature dependent) • Cool weather during fertilization decreases fruit set

  25. Fruit Set • Fruit Set- percent of flower buds that develop fruit • Auxins (hormone) are released from pollen tube which stimulates growth of ovarian tissue • Factors affecting fruit set: • Temperature • Light (photosynthesis) • Stored carbohydrates • Water • Nutrients ~ primarily Zn and B

  26. Fruit • Grapes are true berries • primary tissue from ovarian tissues • Berry size influenced presence or absence of seeds and then seed mass • V. vinifera- 1-2 seeds • V. lubrusca >2 seeds • Seedless grapes • Most not really seedless (stenospermocarpic) • Seeds form, but abort • Still enough hormone production to stimulate large berry growth • Truly seedless (parthenocarpic) have smaller berries

  27. Berry Composition • 75-85% water • 15-25% sugar • 0.5-1.0% organic acids (malic, tartaric, citric) • 0.25% pectin • Secondary metabolites

  28. Berry Composition:Secondary Metabolites • Components that make grapes distinctive • Not essential for survival of the plant • Thousands have been identified, likely many more • Phenolics, anthocyanins, flavenoids • Synthesis is genetically controlled • Influenced by: • Environment, plant age

  29. Phase I Phase II Phase III

  30. Berry Development:Phase I (0-40 DAF) • Phase I- cell division and expansion • 17 cells to 200,000 (600,000 cells at veraison) • No carbohydrate accumulation • Accumulation of tartaric and malic acid • Duration is similar for most cultivars • Berries are green due to cholorophyll

  31. Berry Development:Phase II (40-60 DAF) • Phase II-lag phase • Slowest phase of development • Berries are firm • Berries begin to loose chlorophyll • Organic acids accumulation peaks

  32. Berry Development:Phase III (60-120 DAF) • Phase III- Fruit softening (véraison) • Rapid berry growth (cell enlargement) • Initiation of ripening • Chlorophyll breaks down • Anthocyanins accumulate in skin (red grapes) • Sugars accumulate • Organic acids decline • Secondary metabolites accumulate

  33. Cabernet Sauvignon Flame Sauvignon blanc

  34. Propagation • Cuttings root easily • Cut canes with three nodes (bud) • Can also tip layer • Be careful about propagating your own material • Royalties, quality, identity

  35. Summary • Spend the time to understand the critical growth periods of the grape • Grapes are one of the most complex crops to grow • Before you grow it, be sure you know it!

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