NH - Unit 2 - The Vine - vine species and varieties Flashcards
Explain the species Vitis Vinifera
- Only vine species to survive the quarternary ice ages in Europe.
- Variable vigour and ripening period.
- Adaptable to many soil types.
- Not resistant to phylloxera.
- Not resistant to nematodes.
- 2 subspecies
- V. Vinifera Sativa which is the cultivated vine,
- V. Vinifera Silvestris which is the ancestor of all grape varieties, not hermaphroditic, and almost all eliminated by phylloxera.
Explain V. Vinifera Sativa
the cultivated vine
5 - 10 000 wine producing varieties
selected to be hermaphroditic for good fruit set and relatively large fruit
Explain V. Vinifera Silvestris
- the ancestor of all grape varieties
- not hermaphroditic, and almost all eliminated by phylloxera.
- wild European vines
Explain vitis labrusca
- Found in N.E USA.
- Strong, dark berries, “foxy” aroma.
- Not often used as a rootstock parent.
- common parent in American hybrids as Concord
Explain Vitis riparia
- Found mainly wild on river banks in central-eastern North America.
- used as a rootstock
- Rootstocks low in vigour and surface rooting.
- Encourage early ripening.
- Good phylloxera resistance.
- Suffer from iron deficiency (chlorosis) in chalky soils.
- Used to control vigour on fertile soils.
prefers humid, cool, fertile soils
explain Vitis rupestris
- wild growing on light soils in south-central USA.
- Used primarily as rootstock.
- Vigorous, with a deep rooting system.
- Good resistance to phylloxera.
- Susceptible to iron deficiency (chlorosis).
- Used for poor soils with limited water.
prefers : Deep, poor, healthy soils
explain Vitis berlandieri
- Grown on chalky soils in south USA and Mexico.
- Vigorous and deep-rooting.
- High resistance to chlorosis.
- Cuttings have poor rooting ability.
- Hybridised with riparia and rupestris.
=> Lime-resistant rootstocks that root easily; variable vigour.
What is the cost of a grafted vine?
4 tot 5 times the cost of an ungrafted cutting
Why do they us rootstocks in areas that are unaffected by phylloxera?
Adjusting yield, vigour and ripening times
Phylloxera Vastatrix
- A louse that was accidentally introduced from the USA in 1863.
- Destroyed 2/3rds of European vineyards late 19th century
- Vines die of drought in patches that increase in size year on year.
- Roots of infected vines covered with insects - oval yellow-brown dots surrounded by lemon-yellow eggs.
- Pale green leaf galls on underside on leaves.
- Nodosities (whitish or yellowish growths) near the root tip and tuberosities (swellings) on older roots.
Why are American vine species resistant to Phylloxera?
They form hard, corky layers in the roots beneath the feeding wound of the phylloxera,
- making it harder for the louse to feed
- preventing the invasion by other microbes : bacterias and yeast
How can one prevent distruction by phylloxera?
- Grafting vitis vinifera on rootstocks of American vine species (discovered by Laliman
- growing on sandy soils
- flooding the vineyard 40 days a year
What are nematodes?
Tiny roundworms.
- Common, too small to see with naked eye.
- Pratylenchus and Meloidogyne can damage whilst feeding off roots.
- Xiphinema Index can transmit viral diseases.
What rootstocks are chosen for tolerance to lime?
- vitis vinifera => lime-tolerant
- vitis riparia, vitis ripestris => suffer from chlorosis in chalky soils
=> hybrids have been developped with vitis berlandieri that are more resistant to lime.
=> level of lime must be assessed prior te planting
to what problem leads excess salinity?
will disrupt water uptake and vine nutrition.
