Chapter 4: The Vine

Question 1

Name and describe the two most important vine species

Answer 1

Vitis vinifera
–Main Eurasian species, produces nearly all grapes used in winemaking

American vines

• -Native to North America.
• -Rarely used for winemaking because of unattractive flavours,
• -Resistant to Phylloxera so are widely used to produce rootstocks onto which V. vinifera vines are grafted.

Question 2

Techniques used for growing/propagating of a variety

Answer 2

Cutting
– Section of vine shoot is planted and grows as a new plant (widely used in commercial nurseries that sell vines to growers)

Layering

• • A cane is bent down and a section is buried in the ground with cane tip pointing upwards
• -Cane linking the new growth to the original plant is cut.
• -Risks phylloxera.

Question 3

How can a new grape variety be created? Describe and give examples of the two types of new varieties that can be produced.

Answer 3

Achieved via cross-fertilisation:

• -Pollen from male part of one plant is used to pollinate the female part of another plant.
• -A successful fertilisation leads to grapes with seeds
• -Seeds are planted from which the new variety grows (i.e. has different genetic material)

Crossing:

• -Two parents of the same species
• -Although technically all grape varieties today are crossings, the term is usually reserved for new varieties bred by researches
• -Cabernet Sauvignon = Cabernet Franc x Sauvignon Blanc
• -Müller Thurgau = Riesling x Madeleine Royale
• -Pinotage = Pinot Noir x Cinsault
• -Zweigelt = St Laurent X Blaufränkisch

Hybrid:

• -Parents come from two different vine species, typically with at least one being an American vine. –Typically not used in winemaking EXCEPT Vidal (Canada).
• -Hybrid/American Vine crossings typically used as rootstocks

Question 4

Draw and describe vine anatomy, including types of wood

Answer 4

Tendrils:
–support the vine, wind tightly around a trellis wire for example to keep shoot upright
Buds:
–Form in the join between leaf and shoot, called embryonic shoots.
–Matures inside its casing and contains all structures that will become the shoot, leaves, flowers and tendrils the following year.
Flowers and berries:
–Flower has male and female parts, grouped in bunches called inflorescences.
–Each pollinated flower becomes a berry, and inflorescence becomes a grape bunch.
–Animals eat the berries to disperse seeds.
Leaves
–photosynthesise by using sunlight to convert CO2 and Water to glucose and O2. Glucose supports vine and grape growth, responsible for sugar in grapes

One-year-old wood:
–Shoots turn woody in Winter and become ‘one-year old wood’ in the following Spring
–Vines only produce fruit from shoots grown from buds that developed the previous year
–Winter pruning leaves either a cane or a spur: Cane (long, 8-20 buds), spur (short, 2-3 buds)
Permanent wood:
–Wood >1y old.
–Pruning restricts amount of permanent wood.
–Includes trunk and arms of vine (if present) - configuration varies
Roots:
–Absorb water and nutrients from soil
–Anchor vine
–Store carbohydrates to survive winter.
–V. vinifera grafted onto root systems of other species for Phylloxera resistence

Question 5

What is Phylloxera?

Answer 5

An insect native to North America, which V. vinifera is unable to defend itself against.
Complex life cycle:
–Lives underground and feeds on roots, then infections enter through feeding wounds which weakens and kills vine over several years
–Widely destroyed European vineyards in the 19th century
–American vines can inhibit the louse by clogging its mouth with a sticky sap, and form protective layers behind feeding wound preventing secondary infections.
–Still a problem in nearly every vineyard area of the world (except Chile, parts of Argentina, South Australia).
–Can only restrict by strict quarantining.

Question 6

Name and describe types of grafting

Answer 6

Bench grafting

• -Automated
• -Short sections of cane from V. vinifera and rootstock variety are joined together by machine and stored in warm environment to encourage both parts to fuse together.
• -The vine can be planted after, and takes at least 3y to produce a commercial crop

Head grafting

• • Useful if a grape grower wants to switch to a different grape variety between seasons in an established vineyard.
• -Existing vine is cut back to its trunk and a bud/cutting of new variety is grafted onto the trunk.
• -A successful graft will produce the fruit of the new variety next vintage.
• -Allows quick adjustment to changing market demands.
• -Cheaper than replanting the whole vineyard, and new variety starts life with an established root system.

Question 7

Characteristics of grape varieties to be considered for grape growing

Answer 7

Budding and ripening times

Resistance to certain diseases

Question 8

What is a clone?

Answer 8

Each individual vine or group of vines from the same grape variety that display a particular set of unique characteristics

Question 9

Describe the process of clonal selection

Answer 9

A grower will select for desirable characteristics caused by positive mutations between individual vines of a single grape variety, and further propagate this clone via cutting/layering.

Question 10

Give an example of clones from an original plant that is so different it is treated as a different variety

Answer 10

Pinot Blanc and Pinot Gris are mutations of Pinot Noir.