Chapter 4: The Vine Flashcards
1
Q
Vine Species:
A
There are many different species of vine that have evolved through out the world, but grape growers are only concerned with a handful of these species. In modern viticulture the most important species are
2
Q
Types of Vine Species are:
A
- Vitis Vinifera:
- This is the main Eurasian species
- It produces nearly all the grapes used in wine making and has been used to make wine for several thousands years - American Vines:
- There are three important species of vine native to North America: - Vitis Labrusca
- Vitis Riparia
- Vitis Rupestris
- They are rarely used to produce grapes for wine making because the wines they produce are widely considered to have unattractive flavours
- Unlike V. Vinifera they are resistant to Phylloxera ( a vine pest that attacks the vine roots)
- They are widely used to produce rootstocks onto which V. Vinifera vines are grafted
3
Q
Grape Varieties:
A
- There are thousands of grape varieties belonging to the V. Vinifera species
- For the wine consumer the principal differences between grape varieties are variations in Colour and Flavour, both properties coming from the grape itself
- Differences between varieties are not just limited to the taste and quality of the fruit
- When selecting a grape variety the grape grower will also be concerned with other factors, such as:
1. Budding and Ripening times
2. Resistance to certain diseases - In order to understand what a grape variety is, it is necessary to understand how a variety is Grown or Propagated. This cannot be done using seeds
4
Q
In order to preserve the unique qualities of a variety, a grower must use one of two techniques:
- Cutting
- Layering
A
- A Cutting, is a selection of a vine shoot that is planted and then grows, as a new plant. This method is widely used in commercial nurseries that sell vines to growers
- A Layering, takes place in the vineyard:
1. A cane is bent down and a section of it is buried in the ground
2. The cane tip points upwards out of the ground
3. The buried section takes root and once these roots are established, the cane linking the new growth to the original plant is cut - Due to the risk of Phylloxera most grape growers now use Cutting instead of Layering
- In both these instances the new plant is identical to the original
- A grape variety is a group of individual plants that can all trace their lineage back through a series of Cuttings and/ or Layerings to a single plant
- The terms “ Vine Variety” and “ Grape Variety” can be used interchangeably and the word “ Cultivar” is sometimes used instead of “ Variety”
5
Q
Clones:
A
- All the individual vines of a grape variety are genetically identical,it is still possible to observe variations between them
- This happens as a result of mutations that sometimes occur when the vine grows
- These mutations can sometimes be positive and can result in plants with better quality fruit or better disease resistance
- Often vines with positive mutations are selected for further propagation by cutting or layering, so that positive characteristics of these vines can be carried forward in new plantings
( This is known as Clonal Selection and it has led to the development of different clones)
6
Q
Clones ( Continued):
A
- In grape growing each individual vine or group of vines that shows a particular set of unique characteristics is known as a Clone
- The difference between clones is often small and all of the individual plants that make up a clone would still be considered to be from the same grape variety
- When grape growers order new plants from a nursery they will often specify which clone they would like as well as the grape variety
- Some mutations have such a significant effect that the resulting plants are treated as if they are new varieties, even though strictly speaking they are clones of an original plant
Ex. ( Grape varieties: Pinot Blanc, Pinot Gris, Pinot Noir and Meunier are all mutations of an ancient grape variety called Pinot)
7
Q
Creating New Vine Varieties:
A
- Researches are constantly looking for grape varieties that are better, able to thrive in certain climates and soil conditions as well as varieties with improved disease resistance and those able to deliver a higher quality or quantity of grapes
- Rather than waiting for a random mutation to occur genuinely new grape varieties can be created in controlled conditions using Cross-Fertilisation
- Cross- Fertilisation: This is where pollen from the male part of a flower of one vine is transferred to the female part of the flower of another vine and fertilisation occurs. The pollinated flower develops into a grape with seeds
- If a seed is planted and grows it will be a new variety because its genetic material will be different from that of its parents. A new variety will be produced even if the parent vines are from the same grape variety
- The new variety have some characteristics that are recognisable from the parent vines but this is not always the case
- Traditionally the producer needed to wait at least two or three years before the vines flowered and produced grapes to see what characteristics the young vines would demonstrate
- As knowledge of grapevine genetics has increased it has become easier for scientists to use genetic markers to select the off-spring with the characteristics they desire without waiting this period
- Despite this new varieties rarely come to market, the main reason being the resistance of consumers to unknown grape varieties
- The new variety have some characteristics that are recognisable from the parent vines, but this is not always the case
- Traditionally, the producer needed to wait at least two or three years before the vines flowered and produced grapes to see what characteristics the young vines will have
8
Q
The Anatomy of the Vine:
A
- All wines have a similar structure. These can be divided into four sections:
1. The Green parts of the vine
2. One year old wood
3. Permanent wood
4. The roots
9
Q
The Green Parts Of the Vine:
A
- These are the parts of the vine that grow each new year
- The principal structure is a shoot
- Along the length of each shoot, there are:
1. Leaves
2. Buds
3. Tendrils
4. Flowers or Berries
10
Q
- Leaves:
A
- These are the plant’ s engine
- They are principally responsible for photosynthesis, which is the process by, which plants use sunlight to convert water and Carbon dioxide into glucose and oxygen
- Glucose is a sugar that is used to support vine growth and make ripe grapes taste sweet
11
Q
- Buds:
A
- These form in the join between the leaf and the shoot and can be described as Embryonic Shoots
- Once formed they mature inside their casing, during the growing season, so that by the end of they year, each bud contains in miniature all the structures that will become the: Shoot, Leaves, Flowers and Tendrils the following year
12
Q
- Tendrils:
A
- Vines are not able to support themselves, so they use tendrils to grip a supporting structure in order to stay upright
- Once a tendril senses that it has touched a structure, such as a trellis wire, it will wind itself tightly, around the wire in order to keep the shoot upright
13
Q
- Flowers and Berries:
A
- Flowers are the vines reproductive organs
- A vine’s flowers have both male and female parts, and are grouped in bunches called Inflorescences
- Each flower that is successfully pollinated will become a berry and so the Inflorescences will become the bunch of grapes that will be harvested at the end of the growing season
- The vine has evolved, so that the sweet grapes are attractive to animals, that eat the grapes and disperse the vines’s seeds
14
Q
One Year Old Wood:
A
- Shoots turn woody during the winter, after they have grown
- The following spring, they become one year old wood and the buds that formed on them the previous year, burst and grow into shoots
- Managing the one year old wood is vital for the grape grower, because vines will normally only produce fruit on shoots that grow from buds that developed the previous year
- Every winter the vine is pruned and the one year old wood, will either be called a “ Cane” or a “ Spur”, depending on how many buds it is left with
- A “ Cane” is long with eight (8) to 20 buds
- A “ Spur” is short and has only two (2) to three (3) buds
15
Q
Permanent Wood:
A
- This is wood that is more than one year old
- In the vineyard the amount of permanent wood is restricted by pruning
- The permanent wood is made up of the trunk and where present the arms of the vine
- Not every vine has the same configuration of permanent wood
16
Q
The Roots:
A
- Their function is to absorb water and nutrients from the soil anchor the vine and store carbohydrates to allow the vine to survive the winter
- In modern vineyards, most V. Vinifera are grafted onto root systems from other species, because they cannot resist Phylloxera
17
Q
Crossings:
A
- When a new variety is produced from two parents of the same species, it is called a Crossing
- This term is most commonly used when talking about V. Vinifera, although Crossings of American Vine exist too
- Every grape variety used today is a Crossing
Ex. Modern DNA Techniques, have shown that Cabernet Sauvignon is a crossing of Cabernet Franc and Sauvignon Blanc - This term is more normally reserved for new varieties, that were bred by researches
Ex. Muller Thurgau ( Riesling* Madeleine Royale)
Pinotage ( Pinot Noir* Cinsault) are well known examples of
18
Q
Hybrids:
A
- For grape growers a hybrid is a vine, whose parents come from two different vine species
- Typically hybrids will have at least one American vine as a parent
- The grapes from American vines are rarely used in winemaking. This is true of their hybrids too, although there are some notable exceptions, such as: Vidal which is grown in Canada
- Hybrids and American vines crossings have a crucial role in modern grape growing. They are used throughout the world as Rootstocks
19
Q
Phylloxera and Rootstocks:
Phylloxera:
A
- Phylloxera is an insect that is native to North America and V. Vinifera is unable to defend itself against this pest
- It was able to cause the wholesale destruction to the vineyards of Europe when it was accidentally introduced in the 19th century
- Phylloxera has a very complex life cycle, taking different forms throughout the year
- During one phase: It lives underground and feeds on the roots of the vine
- Infections enter through the feeding wounds and over the coarse of a few years the vine is weakened and ultimately dies
- American vines which evolved with Phylloxera are able to inhibit the underground louse by clogging its mouth with a sticky sap
- They also form protective layers behind the feeding wound, preventing secondary infections
- Phylloxera is now a problem in nearly every vineyard area of the world
- There are some exceptions, such as:
Chile
Some parts of Argentina
South Australia - Strict quarantine procedures are the only protection against infection
20
Q
Rootstocks:
A
- Phylloxera cannot be controlled with chemicals and when it struck Europe in the late 19th century, the only certain way of dealing with it was to plant American species or hybrids
- By the end of the 19th century a better, if more expensive solution was found
- V. Vinifera could be grafted onto the rootstock of an American vine or hybrid
- This offered the protection of the American vine and the flavour of the European vine
- It has been found that rootstocks can provide many other advantages besides Resistance to Phylloxera and a large number of hybrids have been bred accordingly
Ex. Specific rootstock can be used to protect against Nematodes and provide better resistance to drought conditions - Rootstocks are often, used in parts of the world where Phylloxera is not a problem, despite the extra cost involved in buying grafted vines
21
Q
Grafting:
A
- Grafting is the technique used to join a rootstock to a V. Vinifera variety
- The most popular modern technique is Bench Grafting:
An automated process that is carried out by specialist plant nurseries
Short sections of cane from both the V. Vinifera variety and the rootstock variety are joined together by machine and stored in a warm environment in order to encourage the two parts to fuse together. Once this happens the vine can be planted - Another form of grafting called Head Grafting, which is used if a grape grower with an established vineyard decides to switch to a different grape variety between seasons:
1. The existing vine is cut back to its trunk and a bud or cutting of the new variety is grafted onto the trunk
2. If the graft is successful the vine will produce the fruit of the new variety at the next vintage
3. It takes a newly planted vine a minimum of three (3) years to be able to produce a commercial crop - This technique can allow the grower to adjust quickly to changes in market demand
- It is also cheaper, than replanting the whole vineyard and the new variety starts life with an established root system
