The Vine Flashcards
What are 2 vine species relevant to modern viticulture?
- Vitis Vinifera
- American Vines
What species produces nearly all grapes used in wine making?
Vitis Vinifera
What species are widely used to produce rootstocks (mainly) because of their resistance to Phylloxera?
American Vines
What is Phylloxera?
An insect that feeds upon the root system of vine plants, leaving wounds that get infected and eventually kills the vine.
How are American vines resistant to Phylloxera?
American vines defend themselves by producing a sticky sap clogging the mouth of Phylloxera and by releasing a protective layer behind the feeding wound that prevents further infections.
Why American vines are rarely used to produce grapes for winemaking?
Because the grape they produce are widely considered to have unattractive flavors.
What would a grower consider when selecting a grape variety rather than another when establishing a new vineyard?
-Local regulations
-Taste and quality of fruit
-Budding and ripening time matching the local climate
-Resistance to local disease pressure
What are 2 techniques used in the propagation of vines?
- Cuttings
- Layering
Why seeds are not suitable in propagation of vines?
Because each seed will produce a different grape variety which may have very different characteristics from its parent vine.
Why are cuttings of Vitis Vinifera grafted on American rootstocks in nurseries before propagation in a vineyard?
Mainly because unlike Vitis Vinifera, American rootstocks are resistant to Phylloxera
Why is layering not a suitable technique of propagation in vineyards where Phylloxera is present?
Because Vitis Vinifera is not resistant to Phylloxera
Why are grapes produced from cuttings all similar in characteristics?
Because they have the same genetic material.
What is a clone?
A clone is a vine that can be traced back to a single parent vine. It might have been selected for propagation through cuttings because of a slight desirable positive mutation.
What is mutation?
Mutations may occur as a result of the plant adapting to its environment. Over time, the mutation may have such a significant effect that the plant is treated as a new variety. (Pinot Blanc and Pinot Gris are significant mutations of Pinot Noir)
What is a natural Crossing?
A new variety produced by natural (wind-induced) cross-pollination of flowers from two parents of the same species : For example Cabernet Sauvignon is a natural cross between Cabernet Franc X Sauvignon Blanc. The seeds of grapes were later animal-dispersed and grown into new vines.
What is a human bred Crossing?
A new variety produced in a research center by scientists looking to create a new variety for a specific purpose: For example, Müller-Thurgau is a cross between Riesling X Madeleine Royale. Pinotage is a cross between Pinot Noir & Cinsault.
What is an hybrid?
A new vine from parents of different species: typically a cross between a Vitis Vinifera and an American Vine. These are typically used for rootstock production but not only (Vidal is an hybrid used for the production of grapes destined to wine production in Canada)
Beside their resistance against Phylloxera, rootstocks have other useful characteristics…
- Resistance to nematodes (microscopic worms attacking root systems)
- Resistance against drought
- Adaptability to specific soils
Name two wine provenances free of Phylloxera.
Chile & parts of Australia (thanks to a combination of factors such as isolation/ natural barriers and strict quarantine protocols)
What is Grafting?
A general term for joining a rootstock to a vitis vinifera variety.
Why would a grower use the technique of “head grafting” in an established vineyard?
To switch to a different grape variety between seasons. (Thereby saving time and costs of pulling out old vines and replanting new ones which would takes years to grow a viable crop)
In a vine, what are 3 key functions of the root system?
- Absorb nutrients & water from the soil
- Anchor the vine in the ground
- Store carbohydrates for winter survival
In a vine, what is the main function of flowers?
Inflorescences are the reproductive organs of the vine
In a vine, what is the main function of tendrils?
Tendrils grip on any supporting structure to help vine grow upward and find light.
What is contained in a bud by the end of the growing season?
Buds contain in miniature all the structures that will become shoot, leaves, flowers and tendrils the following years.
What is one-year-old wood?
A shoot that turned woody during the winter after it has grown. These are typically pruned to (short) spurs or a (long) canes depending on the number of buds left on them, which determines the crop for the following year.
What is permanent wood on a vine?
More than one-year-old structures (trunk and sometimes arms) of the vine that remains after pruning every winter.
