D1 Viticulture: Anatomy and Growth Cycle

Question 1

During what months are vines dormant in the Northern and Southern Hemispheres?

Answer 1

Northern Hemisphere: November - March

Southern Hemisphere: May - September

Question 2

Below what temperature do vines go dormant?

Answer 2

10ºC (50ºF)

Question 3

At what temperature does freeze injury/damage occur?

Answer 3

-20ºC (-4ºF)

Question 4

Temperatures below −___°C (−___°F) will kill most V. vinifera.

Answer 4

−25°C (−13°F)

Question 5

Vineyards facing west, which get afternoon sun, can experience what issues?

Answer 5

1. Vineyard may become too hot, particularly if it’s in a warm climate;
2. Grapes face increased risk of sunburn.
3. In certain climates, west-facing vineyards tend to endure damper, cooler weather conditions.

Question 6

What are 3 advantages of sloping vineyards?

Answer 6

1. Cold, dense air moves downhill displacing warmer air to higher levels, which produce warm thermal layers on the slope (like the Côte d’Or).
2. Soils on slopes tend to be poorer, more coarsely textured and better drained;
3. Slopes increase the angle at which solar radiation hits the Earth’s surface, thereby increasing the intensity of heat and light which in turn helps the grapes achieve greater ripeness and concentration.

Question 7

What are some disadvantages of sloping vineyards?

Answer 7

1. Increased risk of erosion;
2. Higher costs as it requires hand harvesting.

Question 8

What are four advantages of vineyards being planted close to a body of water?

Answer 8

The body of water:

1. Reflects the sun’s rays;
2. Provides source for irrigation;
3. Reduces risk of ground frost;
4. Can provide morning mists to encourage development of noble rot.

Question 9

What are the advantages of a vineyard being planted close to a forest?

Answer 9

The trees can act as a windbreak, store heat in cold weather, and reduce erosion.

However, forests can also harbor flocks of birds, which are pests.

Question 10

Temperature directly affects the yield of a vineyard by influencing:

Answer 10

1. Vigor of the vines;
2. Number of flower clusters and their size;
3. Fruit set.

Question 11

Temperature directly affects the quality of a vineyard by influencing:

Answer 11

1. Yield level;
2. Accumulation of sugars and the reduction of acidity in the berry;
3. Development of wine aromas.

Question 12

What is something a winegrower can do in a cool climate to increase the rate of photosynthesis?

Answer 12

Increase the amount of leaf area and canopy to compensate for slowed photosynthesis.

Question 13

List 5 major soil types.

Answer 13

1. Limestone
2. Chalk (lower density than limestone, so more free draining)
3. Slate
4. Granite
5. Volcanic

Question 14

Why aren’t vines often planted as seeds?

Answer 14

Propagation from cuttings is quicker and easier;

• plus, propagation allows for grafting onto phylloxera-resistant rootstock

Vines grown through seeds are not genetically identical to the parent vines and although they can show similar characteristics to their parents, more often they are notably different

Question 15

What is the most important aspect of winter pruning?

Answer 15

Winter pruning dictates the number and location of buds that will form shoots in the next growing season.

Heavily pruned vines will grow fewer shoots the following summer (and so grow fewer leaves).

Question 16

What does the term ‘vine vigor’ refer to?

Answer 16

It refers to the general growth of the vine, and a vine’s vigor has ramifications on the yield and ripening of the grapes.

Question 17

What are three factors that influence a vine’s vigor?

Answer 17

1. Available resources for the vine (water, nutrients, temperature);
2. The vine’s variety, clone, and rootstock;
3. Whether disease lives in the vineyard where the vine is planted, which can lower vigor.

Question 18

What are three things that can cause excessively low vigor, and what is the solution for each?

Answer 18

1. Drought stress –> solved by irrigation (where allowed);
2. Low soil fertility –> solved by increased fertilization and drainage;
3. Disease –> solved by diagnosis and treatment.

Question 19

Chlorosis, yellowing of the foliage, is caused by what?

Answer 19

A deficiency of iron, nitrogen, magnesium, and/or sulfur.

Question 20

Chemical weed control (herbicides) can be organized into three groups:

Answer 20

1. Pre-emergence herbicides;
2. Contact herbicides;
3. Systemic herbicides.

Question 21

Pre-emergence herbicides:

1. Where and when are they best applied?
2. How are they absorbed?
3. What do they inhibit?

Answer 21

1. Best applied to surface soil before weeds grow;
2. Absorbed through the roots;
3. Inhibit the germination of seedlings.

Question 22

Contact herbicides:

1. To what are they applied?
2. What do they destroy?

Answer 22

1. Sprayed onto established weeds;
2. Destroy the green parts of the weed that are sprayed, resulting in the death of the plant.

Question 23

Systemic herbicides:

1. What are they sprayed onto?
2. How are they absorbed?
3. What do they destroy?

Answer 23

1. Sprayed onto established weeds;
2. Absorbed by the leaves and translocate in the sap (move upward and downward in the plant);
3. These destroy the whole plant.

Question 24

How can wind damage be mitigated?

Answer 24

1. Artificial Wind Breaks - mobile structures that provide instant protection. Expensive and will need to be replaced;
2. Natural Wind Breaks - must be planted before vineyard is planted and established, e.g. trees with dense foliage. Trees can harbor pests and disease, and may need pruning and other maintenance.

For maximum effect the crop should be within 10x the height of the break.

Question 25

What is lutte raisonée (aka integrated viticulture, or integrated pest management)?

Answer 25

• Synthetic agrochemicals are permitted but only when there is a clear need;
• Vineyards must be constantly monitored for pests and disease;
• Complete list of fertilizers, pesticides, and cultural practices are submitted and grower is inspected at least once per year.

Question 26

Are biodynamic growers permitted to use Bordeaux mixture and/or sulfur?

Answer 26

Yes, biodynamic growers are permitted to use Bordeaux mixture and/or sulfur.

Bordeaux mixture: 3 kg/ha

Sulfur: 7 kg/ha

Sometimes dynamized ashes of target pests are sprayed onto the foliage in an attempt to control the pest.

Question 27

What are the main sugars found in grapes?

Answer 27

Glucose and fructose, both metabolized by yeast.

Question 28

Fructose is found in what kind of grapes?

Answer 28

Late harvested. Fructose is more difficult to ferment.

Question 29

What happens if you have high concentrations of pectins in your grape juice?

How do you handle it?

Answer 29

Pectins make it difficult to extract and/or clarify grape juice (many aromatic varieties are high in pectins, e.g. Gewürztraminer and Viognier).

Remedy this by adding pectolytic enzymes during grape processing.

Question 30

What are phenolic compounds?

Answer 30

A group of chemical compounds that affect a wine’s color, texture, astringency and bitterness.

Smaller phenolic molecules (catechins and epicatechins) can taste bitter or waxy, or develop bitter tastes with oxidation.

Question 31

Are anthocyanins phenolic compounds?

What are anthocyanins responsible for?

Answer 31

Yes, anthocyanins are phenolic compounds.

They are responsible for red wine color, and are found in the skins.

Question 32

Are tannins phenolic compounds?

What are tannins responsible for?

Answer 32

Yes, tannins are phenolic compounds.

They are responsible for astringency and contribute to the weight and body of the wine.

(They are also antioxidants and preservatives.)

Question 33

What is the difference between aspect and slope?

Answer 33

Slope is the angle of incline of the terrain.

Aspect is the direction the slope faces (east facing, west facing). Aspect relates to the degree of solar exposure.

Question 34

Even though grapevines are drought resistant, they still need a minimum of __ mm of rain per year in cool climates and __mm of rain per year in warm climates.

Answer 34

• 500mm in cool climates;
• 750mm in warm climates.

Question 35

Approximately how many hours of sunlight does a vine require during the growing season?

Answer 35

1300 hours

Question 36

High soil pH (limestone-rich) contributes to higher ____ in grapes.

Low soil pH (acidic soils) can be a deterrent to viticulture. This can be countered by adding ____ to your soil.

Answer 36

High soil pH (limestone-rich) contributes to higher acidity (low pH) in grapes.

Low soil pH (acidic soils) can be a deterrent to viticulture. This can be countered by adding lime to your soil.

Question 37

What are the four most important North American vine species?

Answer 37

1. Vitis berlandieri;
2. Vitis labrusca;
3. Vitis riparia;
4. Vitis rupestris.

Question 38

What are the four anatomical structures of the vine?

Answer 38

1. Main shoots;
2. One-year-old wood;
3. Permanent wood;
4. Roots.

Question 39

What are the parts that collectively make up the canopy?

Answer 39

1. Stem;
2. Buds;
3. Leaves;
4. Lateral shoots;
5. Tendrils;
6. Inflorescences/grape bunches.

These are all structures of the main shoots

Question 40

In the spring, the main shoots of a vine grow from ____ retained from the previous year.

Answer 40

Buds

Compound Buds would also be an appropriate answer

Question 41

What role does a vine’s stem have in regards to how a vine functions?

Answer 41

• Transports water and solutes to and from the various vine structures;
• Stores carbohydrates.

Question 42

What are solutes?

Answer 42

In regards to viticulture, they are sugars and minerals – substances that dissolve in liquid to form a solution.

Question 43

What is the difference between a node and an internode?

Answer 43

Node

• The swelling on the stem where other structures of the vine are attached.

Internode

• the area, or distance, between nodes.

Fun Fact: The distance between nodes is an indicator of the rate of shoot growth, so internode length varies along the cane corresponding to varying growth rates during the season.

Question 44

What does it mean when shoots lignify?

Answer 44

When green shoots turn brown, and become woody and rigid.

Once this happens, that shoot is now referred to as a cane.

Question 45

Where do buds form on the vine?

Answer 45

Between the leaf stalk (petiole) and the stem

Question 46

What are buds made of (read: what do they become)?

Answer 46

Buds become all the green parts of the vine:

• Stem;
• Buds;
• Tendrils;
• Leaves;
• Inflorescences.

Question 47

What are the two main types of buds?

Answer 47

1. Compound buds (also known as latent buds);
2. Prompt buds.

Question 48

What is the main difference between compound buds and prompt buds?

Answer 48

Compound buds form in one growing season and break open in the next growing season;

Prompt buds form and break open in the same growing season.

Question 49

What do compound buds produce?

Briefly describe what is inside a compound bud.

Answer 49

Compound buds produce the main shoots in the next growing season.

Inside a compound bud there is a primary bud (the main growing point) and smaller secondary and tertiary buds; the latter buds usually only grow if the primary bud has suffered damage (e.g. spring frost).

Question 50

What do prompt buds produce?

Answer 50

Lateral shoots

Question 51

On what do prompt buds grow?

Answer 51

They grow on the main shoot which had just grown from a compound bud.

Question 52

Lateral shoots grow from buds formed in the:

• Current year
• Previous year

Answer 52

Current year (because they grow from Prompt buds)

Question 53

Compared to main shoots, lateral shoots are:

• smaller and thinner
• larger and thicker
• the same size

Answer 53

Smaller and thinner

Question 54

What structures do lateral shoots have?

Answer 54

1. Stem;
2. Leaves;
3. Buds;
4. Tendrils;
5. Sometimes inflorescences.

Question 55

What is the main function of lateral shoots?

Answer 55

To allow the vine to continue growing if the tip of the main shoot has been damaged or eaten; they’re especially helpful being an additional source of photosynthesis.

Question 56

Why is it undesirable to have lateral shoots near the base of the main shoot?

Answer 56

They can impede air flow and shade the fruit too much.

They’re usually removed during summer pruning.

Question 57

What are the Pros of keeping the inflorescences on lateral shoots and letting them develop into clusters (also known as a ‘second crop’)?

Answer 57

• If they grow into clusters and are green harvested, their removal is thought to improve the ripening process and enhance the uniformity of ripeness of the remaining bunches;
• If they grow into clusters and are hand-harvested, the vineyard manager can be selective and either give them a longer hang time or the clusters can be separated.

Question 58

What is the profile of bunches from a ‘second crop’ harvested at the same time as the main crop?

Answer 58

• Higher in acidity;
• Lower in potential alcohol;
• Potentially unripe tannins, aromas, and flavors;
• In black grapes, the bunches will have less color development.

Question 59

What role do the tendrils have?

Answer 59

• Provide support for the vine;
• Help position the vine canopy;
• Help keep canopy in place.

Question 60

What are stomata?

Answer 60

Stomata are pores on the underside of leaves that allow a plant to take in carbon dioxide, which is needed for photosynthesis;

They also allow water vapor to diffuse out of the plant, but when conditions are hot or dry they can close to reduce water loss, but limits photosynthesis by preventing carbon dioxide from entering the vine.

Question 61

Where in the vine does photosynthesis mainly happen?

Answer 61

In the leaves

Question 62

What is inflorescence?

Answer 62

A cluster of flowers on a stem which, when fertilized, develops into a bunch of grapes at fruit set.