Chapters 4-6 The Vine & Growing Environment & Vineyard Management Flashcards
What are the 2 vine species important in modern viticulture?
Vitis vinifera
American vines
What is vitis vinifera?
Vitus vinifera is the main Eurasian vine species.
It produces nearly all the grapes used in winemeking.
It has been used to make wine for several thousand years
What is important about American vines?
American vines are resistant to phylloxera and so are widely used to produce rootstocks that Vitis vinifera can be grafted onto
How many grape varieties belong to the vitis vinifera species?
Thousands
What are the 2 techniques in which a grape variety is propagated?
Cutting
Layering
With regards to grape variety propagation, what is a cutting?
A cutting is a section of a vine shoot that is planted and then grows as a new plant
With regards to grape variety propagation, what is layering?
Layering takes place in the vineyard.
Layering occurs when a cane is bent down and a section of it is buried with the tip pointing upwards out of the ground.
When the buried section takes root, the cane linking the new growth to the original plant is cut.
What is a clone?
A clone is an individual vine or group of vines that show a particular set of unique characteristics
Clones occur as a result of mutations that can sometimes be positive and result in plants with better quality fruit or disease resistance
What is cross fertilisation?
Pollen from the male part of the flower from one vine is transferred to the female part of the flower on another vine and fertilisation occurs.
The pollinated flower develops into a grape with seeds
If a seed is planted and grows the resulting vine will be a new variety as its genetic material is different from that of its parents
Why are researchers interested in cross fertilisation?
To develop new vine varieties that may thrive in certain conditions, be resistant to disease or produce higher quality or quantity of grapes
Why are there so few new grape varieties being made with cross fertilisation?
Impos to know the qualities of a new variety
Hundreds of seeds are required
Many seedlings fail in the first year
2-3 years before those that do survive flower and produce grapes
Years to determine long term value of new variety
Process is costly and time consuming
What are the 4 sections of a grape vine?
- the green parts of the vine
- one-year-old wood
- permanent wood
- roots
What is the principal structure of the green part of the vine?
A shoot
What 4 components can be found along the length of each shoot of a grape vine
- Leaves
- Buds
- Tendrils
- Flowers or berries
What is the function of leaves on a grape vine?
Photosynthesis - water and CO2 is converted into glucose and O2
Glucose is required to support vine growth and make ripe grapes sweet
What is the function of buds on a grape vine?
Buds are little embryonic shoots that develop between the leaves and the shoot.
Buds mature inside their casing during the growing season so that by the end of the year, each bud will contain all the structures that will become the shoot, leaves, flowers and tendrils the following year
What is the function of tendrils on a grape vine?
Support
Vines are not able to support themselves so they use tendrils to grip a supporting structure
What is the purpose of flowers on a grape vine?
Reproduction
A vines flowers have both male and female parts (grouped in bunches called inflorescences)
Each flower that is successfully pollinated will become a berry and so the inflorescence will become a harvestable bunch of grapes
What is one-year-old wood?
A shoot that has turned woody the winter after it has grown
Why is one-year-old wood important?
Shoots turn woody during the winter.
The following spring the buds on the woody shoot (now called one-year-old wood) burst and grow into shoots.
Vines will only produce fruit from shoots that grew from buds the previous year.
What is the difference between a cane and a spur?
Both are one-year old wood.
A cane is long with 8 - 20 buds.
A spur is short with 2 - 3 buds.
What is permanent wood?
Permanent wood is wood that is more than one-year-old; trunk and arms of the vine
What is the function of the roots?
Absorb water and nutrients from the soil
Anchor the vine
Store carbohydrates to survive the winter
Most Vitis vinifera vines grafted onto root systems from other species
What is a crossing?
Name 1 example
A new variety of grape vine produced from 2 parents of the same species (eg. Vitis vinifera) although different varieties of that species.
Can occur naturally in nature or due to human intervention
eg Pinotage = Pinot Noir x Cinsault
What is a hybrid?
A new variety of garpe vine produced by 2 parents of different species (eg. American vine x Vitis vinifera)
What is phylloxera?
An insect native to North America that Vitis vinifera is unable to defend itself against
How does phylloxera destroy Vitis vinifera vines?
Phylloxera takes different forms throughout the year
During one phase it lives as underground louse and feeds on the roots of the vine
Infection enters through these feeding wounds and over a few years the vine dies
How do American vines withstand phylloxera?
American vines inhibit the underground louse by clogging its mouth with a sticky sap
They also form protective layers behind the feeding wound preventing secondary infections
What 3 areas in the world do not have a phylloxera problem?
Chile
South Australia
some parts of Argentina
What are 3 advantages of grafting American vine rootstock onto vitis vinifera vines?
Resistance to phylloxera
Protection against nematodes
Resistance to drought conditions
What is grafting?
Grafting is a technique to join a rootstock to a Vitis vinifera variety
What are 2 grafting techniques?
Bench grafting
Head grafting
What is bench grafting?
Short sections of cane from the Vitis vinifera and rootstock varieties are joined together by machine and stored in a warm environment
Once to 2 parts fuse together the vine can be planted
What is head grafting?
The existing established vine is cut back to its trunk and a bud or cutting of the new variety is grafted onto that trunk.
What are 3 advantages of head grafting?
The newly grafted vine will produce the fruit of the new variety at the next vintage
Cheaper than replanting with the new variety
The new variety starts with an established root system
What 5 elements are necessary for vine survival?
Heat Sunlight Carbon dioxide Water Nutrients
Below what temperature is it too cold for vines to grow?
Below 10°C
What 8 factors affect heat in a vineyard?
Latitude Altitude Ocean Currents Fog Soil Aspect Continentality Diurnal Range
What is continentality?
The temperature difference between the coldest and hottest months
How do large bodies of water affect continentality?
Large bodies of water heat up and cool down more slowly then landmasses
Areas near large bodies of water therefore have low continentality
How does continentality effect vineyards?
It will determine the length of the growing season
It will therefore influence what grape varieties can successfully be grown
How does latitude effect vineyards?
Heat & Sunlight
Most vineyards lie between 30° and 50° N and S of the equator, closer is too hot and further away is too cold
Day length during summer is longer the further the vineyard is from the equator. Extra sunlight helps grapes to ripen
How does altitude effect vineyards?
The higher the altitude the lower the temperature. It is possible to grow vines in regions of high altitude and close to the equator. eg Cafayate
How does ocean currents effect vineyards?
Major currents transport large volumes of warm or cold water, leading to localised warming or cooling in certain areas.
Warming Gulf stream
Cooling Humboldt & Benguela currents
How does fog effect vineyards?
Fog cools vineyards allowing grapes to grow in hotter regions
California
Casablanca Valley
How does soil effect vineyards?
Soils that are dark in colour, high stone and rock content can absorb and reradiate heat.
Soils with a high water content can conduct heat away from the vine more quickly
How does aspect effect vineyards?
The vineyards with an aspect facing the equator receive the most heat and sunlight
Steeper slopes benefit even more from this effect.
Mosel, Germany
What is diurnal range?
The difference in daytime and nightime temperatures
What 2 components impact diurnal range?
The proximity to bodies of water.
The level of cloud cover
How do warm and cool nights effect vineyards?
Cool nights help slow the loss of aromas and acidity
Warm nights accelerate ripening
In what 2 ways can a mild winter effect vineyards?
If the winter is mild, the vine will not have a dormant period (may produce more than 1 crop/year) which will result in a shorter life and poor quality grapes
Mild winters also mean more insects survive to attack the vines the following summer
What temperature hazard occurs during Spring?
What are the ramifications?
Spring frost
Cold air below 0°C collects at ground level and freezes any water vapour on the ground or vine. It kills newly burst buds or young shoots
What are the 4 main forms of protection from Spring frost?
Heaters
Wind machines
Sprinklers
Thoughtful vineyard design