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Winegrape Brief History Brought to Europe between 5490 and 490 BC Evidence of wine in Egypt from 2440 BC Seeds in Spain dated from 2340 to1940 BC Wine in China by 2000 BC First recorded wine laws by 1700 BC Winemaking technology by 1400 BC South of France planted by Greeks in 500 BC Spanish brought grapes to CA and AZ English brought grapes to New England Cultivated since 6000-5000 BC Vinifera came from south of the Caspian and Black Seas
Categorized by use Frontenac Sun Pacific Wine Grapes Most grapes in the world are for wine Relatively high acid and moderate sugar for dry wines Low acid and high sugar for desert wines Table grapes Food or decorative Chosen for appearance, taste, shipping, injury resistance, seedless (US)
Categorized by use Raisin Grapes (Thompson Seedless) Soft texture, seedless, early ripening Don t stick together, large and small, dry quick Juice Grapes (Concord and blends) American varieties stand up to processing and pasteurization without flavor loss Canning Grapes (Thompson Seedless) Seedless only
Lateral shoot breaks from node (bud) Clusters opposite nodes 4-6 Latent buds imbedded in wood (water shoots, suckers) No fruit If compound bud dies Secondary clusters generally pruned off Ripening timing Quality of fruit High TA, Low sugar Grape Biology
Vascular Tissue Xylem- Woody Move water Move minerals Phloem- Move carbohydrates from photosynthesis Food mainly in leaf tissue, but any tissue were chlorophyll is found makes some carbohydrate
Dormant Season-Autumn Carbohydrates converted to sugar to protect against cold injury Rest-Internal physiology inhibits growth In November Broke by cytokinins Promoted by gibberellins Quiescence-Environment induced dormancy- In January Must be induced in warm climates Bleeding - closer to Spring time When cut or pruned Not harmful
Annual Cycle of Growth
Spring Vine Growth
Compound Bud Winter bud covered with hard scales Must winter for inflorescence to develop Primary shoot from primary bud (1-4 clusters) Last years cane growth 2 and 3 buds usually dormant (variety dependant) 2 less fruitful 3 survival Picture from University of Michigan (Primary and secondary buds are dead, tertiary is alive) -Live bud tissue tips cut smooth and clean -Dead bud tissue cuts dry and brittle -If you cut too deep it will be green even if the bud is dead
Bud Break to Bloom-Spring Median Daily Temp 50 F (ex: high 70 F - low 30 F = median 50 F) Sustained 50 F for a couple weeks Shoots grow up to 1in per day in warm weather Too hot photosynthesis shuts down Next years flower develops before this years bloom thru harvest
Flowering Inflorescence is the flower cluster (1-4 depending on variety) 2 may break even if 1 is not injured (variety dependant) Bloom 6-10 weeks after bud break weather dependant Maybe hundreds of flowers per cluster
Flowering Calyx-whole flower Pistil Stigma Style Ovary 5 Stamens - Filament Anther (pollen source) Most vinifera are male/female Some have sterile pollen or under developed pistil Rotundifolia male flowers on one plant and female on another Hermaphroditic for cultivation Corolla- 5 green petals, roll up to form cap or calyptra Falls after bloom
Fertilization Anthesis - Full bloom, Full bloom when 50% caps have fallen Cold rain may cause caps to stick, decreasing fruit set between 6-9am with warming or 2-4pm One plant or cluster may take a number of days to come into full bloom Millerandage - (shot berries) many small seedless berries Due to frost or rain
Bloom to Fruit-set Fertilization 2-3 days after pollination Pollen tube penetrates stigma Two sperm travel down pollen tube to ovary (only one merges with the egg) Some varieties can set without fertilization, only pollination needed (Black Corinth) Embryo aborts in Thompson Seedless (no seed forms) Shatter- 50-60% impotent berries and unfertilized Pistils fall Can have too many berries, tight cluster
Bloom- Thin waxy layer on the skin protection from water loss and injury Skins Skin to pulp ratio (winegrapes vs. table grapes) Color (pigments) Pulp- fleshy pericarp Juice (80-90% of crushed grapes) Flavor (volatile and titratable acids) aroma (volatile acids in pulp) Seeds- 0-4 per berry # and size directly related 0-5% wt of crushed grapes 5-8 % wt Tannins (Astringency in wine) combine with pigments over time) 10-20% oils Fruit
Fruit Tannin extraction for wine character Rachis Stems- (2-6% cluster weight) Depends on variety Rachis pedicles
Growth of Grape vs. Time Stage I-Cell division All but embryo and endosperm grow Stage II-Lag phase Embryo and Endosperm grow Lignins form in the endocarp Ovary wall grows Stage III- Mesocarp growth Swelling of fruit Depositing sugars Flavor components develop Seedless varieties have little or no lag phase
Fruit Quality Factors: Variety Age of plant (5-8 years to mature depending on variety and conditions) Resources: ph of soil for nutrients up take Microclimate Last years growing season: weather, sun Crop load (controlled by pruning balance) Plant health: nutrient or resource deficiency lead to viruses, bacteria, and insects
Post Harvest Food stores decline quickly in the Spring for shoot growth until fruit-set Carbohydrates begin to build back up in shoots, canes and roots after fruit-set Fruit load during maturation competes with roots for resources Proper balance of fruit to vegetative growth imperative for winter and cold survival Food stored mainly as sugar in Winter Sugar used for protection, energy, transformed into proteins, fats etc. Previous years pruning weights used to decide fruit load for this year (Dr. Paul Domoto University of Iowa, hybrids: 30 buds for every lb. + 10 for every additional lb., not to exceed 60 buds) Highly variable depending on variety, microclimate, age of plant, health of plant, regional winemaking preferences.
Table/Juice/Raisin Grapes
European White Winegrape Varieties (vinifera) in Nevada
European Red Winegrape Varieties (vinifera) in Nevada
French and American Winegrape Hybrids
Future of the Grape Industry? Pierce s disease Caused by a bacteria Xylella fastidiosa Passed by leafhoppers (Cicadellidae) called Sharpshooters Wiped out 35,000 acres in CA in 1880s Affects the xylem (water conducting vessels) Mid summer vascular tissue is blocked and plants dry out Leaves take a few days to a few weeks to fall, leaving the petiole on the cane Green patches appear on hardening canes New growth is stunted Death in 1-5 years
Pierce s Disease Control Found in Texas, San Joaquin valley Discovered in Napa in 2007 Only control for Pierce s Disease are resistant strains of grapes Andrew Walker UC Davis has 8 new resistant vines from breeding programs Hybrids for blending only (87.5% vinifera) Marketing difficulty Negative affects on flavor and aroma
GMO or #@!$! (Transgenic Grapes) PG proteins found in Xylella f. and grape fungi degrades plant cell walls PG-inhibiting proteins found in plant cells Grape cells (callus) were grown with a bacteria that had the gene inserted into a plasmid 51 lines of grapes created with the protein found in the roots, shoots, and leaves Pierce s Disease was slowed in these plants
References Caldwell, J., (1998). A Concise Guide to Wine Grape Clones For Professionals. Second Edition Viticultural Services. Napa, CA Domoto, P., (2008). Grape Cultivars for Consideration in Iowa. Department of Horticulture, Iowa State University Extension Mullins, M., Bouquet, A., & Williams, L., (1991). Biology of the Grape Vine. Cambridge University Press, Cambridge, UK. Weaver, R., (1976). Grape Growing. John Wiley & Sons Inc. New York.