D1: The propagation of the vine 2 Flashcards
How does the vine Propagate in the modern viticulture ?
by cuttins or layering.
what is a cutting ?
it is a section of a vine shoot that is planted and then grows as a new plant.
— this is by far the most common propagation technique as many small cuttings can be taken from a vine and propagated at the same time.
— it also permits the use of rootstocks, which can easily be grafted onto the vine cutting before it is planted.
— nurseries are able to treat vine cuttings to avoid spread of diseases
what is layering ?
1) Layering is a method of filling gaps in a vineyard (eg due the death of a vine) by using shoots from an established neighbouring vine to produce a new vine.
2) a cane is bet down and a section of it is buried in the ground.
3) the tip of the cane points up out of the ground. the section that is buried takes root and once these roots are established, the cane linking the new growth to the original plant is cut.
4) the vine grown on its own roots, not those of a rootstock and this is method is therefore not always suitable.
5) the new vine will have no protection against phylloxera or have the qualities (such as the desired yield) that a choice of rootstocks offers
why are vines not propagated through seeds ?
they are not genetically identical to the parent vines and although they can show similar characteristics to their parents, more often they are notably different.
—— layering and cuttings create new plants that are usually genetically identical to the parent plant, and therefore have the same characteristics.
The methods of cutting and layering produces vines that are genetically identical to the parent vine. however, at each cell division during plant growth, there is a risk…..
that random mutations in the genetic code will occur.
- many of these mutations have no effect on the vine; however, some will cause the new vine to have slightly different characteristics (eg smaller or larger grapes, thicker or thinner grape skins, more disease or less disease resistance.
—–this cause diversity within the vines of the same grape variety
what happens with vines that after the mutation with particularly favourable characteristics ?
They are selected by the vine nurseries or grape growers for propagation by cuttings in order to grow new vines with these favourable characteristics
—- this is known as clonale selection
Some mutations have such a significant effect that the resulting plants are treated as if they are new varieties. strictly speaking they are clones of original plant.
EG pinot noir, meunier, blanc and gris are all mutations of the grape variety Pinot
Pinot noir is a grape variety with many clones:
Pinot noir clone 115: has low yields of small grapes, making it suited to high quality red wine production
Pinot noir clone 521: higher yields of bigger grapes, making it better suited to sparkling wine production
–this because the high concentrations of tannins and colour from the skins are not needed in these wines
What is the most common way of obtaining new planting material ?
1) buy young vines from a nursery
2) these will typically offer particular clones of grape varieties.
3) the young vines from nurceries are tested to be free from virus infection
4) depending on the region and grape variety, only a very limited number of clones may be available from nurseries
– in some cases the clones may have been chosen for maximising yields rather than fruit quality
5) this means that the vines planted across the vineyards or even the region can be relatively uniform
– especially if natural factors are consistent across the region
— the benefits are easy vineyard management
because the grapes grow some or what the same and ripens even
what is the disadvantage of buying clones of the nurserie ?
If it are clones that are used for maximising yields and less fruit quality:
- there will be less diversity in the fruit and hence potentially producing a wine with less complexity and balance
- it also makes the vineyard more susceptible to disease if they’re uniform, it means they’re more susceptible for some diseases or pests
So for these reasons the grapegrower willl often buy and plant a number of different clones of the same grape variety.
Clonal selection is a relatively recent practise that became common within the last 40-50years.
yes, before this, grape growers would propagate their vines through the proces of mass selection (selection massale)
What is mass selection ?
The vineyard owners takes cuttings from the vines in their own vineyards and cultivate these cuttings.
– the cuttings can be send to a nurserie to graft onto a rootstock when necessary
– cuttings are taken from several vines. generally, the best performing vines are selected
What is grafting ?
This is the technique used to join a rootstock to a vitis vinifera variety. (american rootstock, not good for winemaking, but resistant to phylloxera)
a) bench grafting: most popular technique: both cuttings from vitis vinifera and rootstock are joined together by machine and stocked in a warm environment
b) headgrafting: switch different grapevarieties in an established vineyard by cut the vine back to its trunk and a bud or cutting from another variety is grafted onto the trunk
– it takes a newly planted vine a minimum of three years to produce commercial fruit
– headgrafting can (if succesfully grafted) produce fruit the next vintage
what are the advantages of mass selection ?
1) increases the diversity of planting material in the vineyard and region
2) the owner is using own unique planting material (different from that being bought from the local nursery) which can enhance fruitquality and/ or yield
however, the selection and monitoring of vines to ensure the propagation of the best vines is costly in terms of time and labour.
true
