Ch 4 - The Vine Flashcards
What are the two main species of vine and which is predominantly used to make wine?
- Vitis Vinifera - main species in Europe and produces nearly all grapes used for wine
- American vine - rarely used for wine but used for rootstocks onto which vinifera is grafted because American vine is resistant to Phylloxera
What is cutting? Where is this technique mostly used?
A growing technique where a section of an existing vine shoot is planted and grows as a new plant – mostly used in nurseries
What is layering? Where is this technique mostly used?
Takes place in vineyards where the cane is bent down and a section buried into the ground. The cane tip points up out of the ground and the buried section takes root. Once established, the cane linking the new growth to the old plant is cut.
Which growing technique is more popular and why? (cutting/layering)
Because of phylloxera, most growers use cuttings to avoid layering using infected vines.
Does cutting or layering create a new variety?
No - the new plant will be the same variety as the original one
What is clonal selection?
Where growers select those clones with good mutations for further propagation by cutting or layering to continue the positive mutations being carried forward into future generations.
What is a clone?
Within the same variety it is possible to see variations between plants. These are the result of mutations that may occur while they grow. A Clone is therefore either an individual vine or group of vines with particular set of characteristics distinct from the broader variety.
Does a clone create a new variety?
No - although sometimes they can be so distinct they are treated as if they were e.g. Pinot Gris is a clone if Pinot Noir but is generally treated as its own variety.
How can new varieties be created?
Can be created in controlled conditions using cross-fertilisation – pollen from male part of flower is transferred to the female part of another vine’s flower which then develops into a grape with seeds. If a seed is planted and grows then this will be a new variety. It has different genetic material from its parents – will be a new variety even if both parents are from same variety.
What are some drawbacks to creating new varieties?
It is impossible to know how the new variety will turn out and what characteristics it will have, as they can differ greatly from their parents. It is costly and time consuming because hundreds of seeds are required. Many seedlings fail in the first year and take at least 2 or three before those that manage to survive flower begin to produce grapes. Then it takes time to demonstrate the value of the new variety such that it begins to be picked up by other growers and sold commercially.
What is a crossing? Are they common, give a couple of examples?
A crossing is a new variety produced from 2 parents of same species. They are very common, typically every variety used today is a crossing.
e.g. Cab Sav is a cross of Cav Franc and Sav Blanc; Pinotage is Pinot Noir and Cinsault
What is a hybrid? Where would you expect to see a hybrid?
Vine whose parents come from 2 different species e.g. have american vine and vinifera. Often used in rootstocks
How does American Vine protect itself against Phylloxera?
American vines inhibt the underground louse by clogging its mouth with sap and forming protective layers behind the wound preventing infections.
How does Phylloxera attack vines?
At one stage of its life cycle, it lives underground and feeds on roots of the vine – this gives infections through the feeding wounds and over a few years vine is weakend and dies.
What are rootstocks and why are they used?
A rootstock is where a grower uses the roots of one variety to form the basis of the vine and grafts another variety onto the roots. They are used to protect against Phylloxera and other pests like nematodes. They can also provide better resistance to drought.
