Viti 2: The Vine Flashcards
Family to which Vitis Vinifera belongs
Vitaceae (family of woody climbing plants)
Prompt buds
Buds that break in the same year as their formation
Latent buds
Buds that break in the spring in the spring that follows their formation
Transpiration
The process by which leaves evaporate water, in turn enabling the plant to suck up water from the soil
Petioles
Leaf stalks. Can be analysed to determine nutrient requirements of the vine.
Flowers
Grouped bunches called inflorescences and are hermaphroditic.
Budburst:
Carbohydrates stored in roots throughout winter return to the trunk and canes as sap to give nutrients.
Winter dormancy:
Leaves fall off and shoots lignify (harden and brown).
Coulure:
Poor set brought about by poor light levels.
Millerandage/hen and chicken:
Small berries with no seeds and big berries with seeds all on same bunch brought about by low temperatures.
Vieilles vignes in German:
alte Reben
Hybridisation between species:
Interspecific hybridisation
Vitis riparia
Wild on river banks in alluvial soil, central-eastern N America. Phylloxera resistant, grafts well, low in vigour, ripen early, but suffer chlorosis (iron deficiency) in chalky soils. Good for controlling vigour. Rootstocks tolerant of damp.
Vitis berlandieri
Found on chalky slopes in southern USA and Mexico. Vigorous, deep-rooted and resists chlorosis. Cuttings don’t root well, so often hybridised with riparia/rupestris. High calcium tolerance.
Introduction of downy mildew in Europe from USA
1878
Name of downy mildew
Plasmopara viticola
PDO wines in Europe
Cannot be hybrid
Crosses occurring within same species (one variety with another):
Intraspecific vinifera crosses
Louis Bouschet - Aramon x Teinturier =
Petit Bouschet
Henri Bouschet (son) - Petit Bouschet x Grenache =
Alicante Bouschet (rich in anthocyanins in pulp and skin, deep red).
Group name for anthocyanin-rich black grapes:
Teinturiers
Hermann Müller (from Thurgau, Switzerland) in late C19th
Riesling x Madeleine Royale (table grape) = Müller Thurgau
Mass selection/sélection massale:
Marking out best plants from which to take cuttings. Best done in poor years and involves eliminating plants rather than actively selecting them.
Cloning:
Come from single parent and have same genetic identity. Propagated vegetatively. First carried out in 1876. Risks high yields and easy spread of disease.
Why are Vitis berlandieri and rotundifolia layered rather than rooted from cuttings?
They respond better to layering rather than rooting from cuttings.
Layering:
Only suitable for areas with no phylloxera risk. Famous example: Bollinger’s Vieilles Vignes Françaises.
Cuttings:
Hardwood winter cuttings normally used. Taken in autumn/winter when carbohydrates are highest and is healthy. Softwood harder to propagate, but available all year round.
Length and treatment of cuttings:
30-45cm pieces. Stored at 5 degrees. Heat treatment at 50 degrees for 30 minutes and kills pests, phylloxera, nematodes and phytoplasmas.
Growing cuttings:
Plenty of water, as leaves grow faster than roots (mist propagation/propagating frame). Warmth (15-25 degrees) from below, if possible, to encourage roots. Loose, well-drained soil protected from vine weevils.
Benefits of grafting:
Resistance to phylloxera/nematodes, roots become better adapted to soil conditions (e.g. high lime content) and better control of vigour.
Bench grafting:
Indoors, late winter/early spring. Scions put in damp sawdust and soaked 1-2 days to make less brittle. Done by machine. Molten paraffin wax applied just below graft union. Stored in crates, humidity controlled at 90%, temp. at 21-29 degrees for 3-5 weeks. ‘Callus’ of cells forms at union. They’re then removed, trimmed, re-dipped and put in cold store (1-4 degrees) and put in pots (18-21 degrees for 7-10 days). Can be put in greenhouse (‘forced’) and thus plantable within 10 months.
Top/head-grafting:
Useful for changing varieties in an established vineyard. Scion cutting collected in winter, stored at high humidity and low temps. Almost complete decapitation! Chip-budding and T-budding possible (inserting bud onto existing trunk). Cleft-grafting rare and involves sawing vine trunk vertically and inserting canes. Good for young vines in warm climates, aftercare is vital.
Vitis rupestris:
Wild in light soils in southern centre of USA. Vigorous, deep-rooted, phylloxera-resistant, but risk chlorosis. Good for poor soils with little water. Rootstocks are drought-tolerant.
Vitis labrusca:
Wild in NE USA. Strongly-flavoured, dark berries, ‘foxy’. Not used widely as a parent.
Two subdivisions of Vitis vinifera:
Vinifera sativa: hermaphroditic.
Vinifera silvestris: not hermaphroditic and largely wiped out by phylloxera.
Chardonnay:
Hardy, but prone to grey rot.
Liebfraumilch:
Riesling, Müller-Thurgau, Silvaner and Kerner.
Sauvignon Blanc:
Susceptible to black rot and powdery mildew.
Trebbiano also known as…
Ugni Blanc
Pinot Noir:
Takes up autolytic flavours well (sparkling).
Cabernet Sauvignon:
High vigour, but low yields.
Merlot:
Buds early (prone to spring frost) and prone to coulure.
Syrah:
Can develop reductive (mercaptan) flavours.
Grenache:
Oxidises easily. Known as Cannonau in Sardinia.
Names for Tempranillo:
Tinta Roríz (Douro, Dão), Aragonéz (Alentejo), Ull de Llebre (Catalonia), Cencibel (Valdepeñas) and Tinta del País/Tinta de Toro (Ribera del Duero/Toro).
Zinfandel:
Ripens unevenly, can give excessive alcohol.
Ruby Cabernet:
Carignan x Cabernet Sauvignon - low acidity, soft tannins. Prone to powdery mildew (oidium).
Cost of grafting:
Grafted vines can cost 4-5 times as much as ungrafted cuttings.
Phylloxera first identified in Europe:
1863
Phylloxera symptoms:
Vines die of drought in growing patches, roots infected with insects and their eggs, nodosities (growths on root tip), tuberosities (swellings on roots) and pale green leaf galls.
Discovery of resistance of American vines:
Leo Laliman (Bordeaux), 1872
Why are American species resistant to phylloxera?
Their roots have hard, corky layers beneath where the insect feeds. Also keep other infections out.
Only other ways to combat phylloxera:
Grow on sandy soil or flood the vineyard for 40 days a year!
Nematodes:
Tiny roundworms. Some feed off roots (pratylenchus and meloidogyne) and others spread viral diseases (xiphinema index).
Excess acidity in soil:
Aluminium toxicity
Excess salinity in soil:
Disrupt nutrition and water intake.
Rootstocks and soil depth:
Shallow-rooting stocks used in shallow soils and vigorous, deep-rooting rootstocks used in deep soils.
Why might weak vigour rootstocks be used in cooler climates?
Because they encourage earlier ripening.
