Ch04 The Vine

Question 1

Define Vitis vinifera

Answer 1

Vitis vinifera is the main Eurasian vine species. It produces nearly all the grapes used in winemaking and has been used to make wine for several thousands of years. It is not resistant to Phylloxera.

Question 2

Why are American vines rarely used for winemaking?

Answer 2

Because wines produced are considered to have unattractive flavours.

Question 3

Define grape variety

Answer 3

Grape variety is a group of individual plants that can all trace their lineage back from a series of cuttings and/or layerings to a single plant. Grape varieties differ from each other in colour and flavour.

Question 4

How are grape vines propagated?

Answer 4

Grape vines are propagated via cutting or layering. This means the new plant is genetically identical to the original.

Question 5

Define cutting

Answer 5

Cutting is a section of vine shoot that is planted and then grows as a new plant. This vine propagation method is widely used in commercial nurseries that sell vines to growers.

Question 6

Describe layering

Answer 6

Layering takes place in the vineyard. It is one way to propagate a vine. A cane is bent down and a section of it is buried in the ground. The cane tip points upwards out of the ground. The buried section takes root. Once these roots are established, the cane linking the new growth to the original plant is cut. Used in areas where Phylloxera is not an issue.

Question 7

Define clone

Answer 7

Clone, in grape growing, is each individual vine or group of vines that shows a particular set of unique characteristics.

Question 8

Define clonal selection

Answer 8

Clonal selection is when a vine mutates and its new positive characteristics are propagated by cutting or layering.

Question 9

Name grape varieties that are mutations (clones)?

Answer 9

Grape varieties Pinot Blanc and Pinot Gris are both mutations (clones) of the grape variety Pinot Noir.

Question 10

Define cross-fertilisation

Answer 10

Cross-fertilisation is when 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.

Question 11

Why are seeds not suitable for growing vines?

Answer 11

Seeds are not suitable for growing vines because if a seed is planted and grows, it is a new variety. Its genetic material is different to its parents. A new variety is produced even if parent vines are from the same grape variety. The new variety may have some characteristics that are recognisable from parent vines, but not always. You don’t know what qualities a new variety will have.

Question 12

Define crossing

Answer 12

Crossing is when a new variety is produced from two parents of the same species. e.g. Cabernet Sauvignon is a natural crossing of Cabernet Franc and Sauvignon Blanc.

Question 13

Give 3 examples of crossings

Answer 13

3 examples of crossings are:

• Cabernet Sauvignon from Sauvignon Blanc and Cabernet Franc.
• Pinotage from Pinot Noir and Cinsault.
• Müller-Thurgau from Riesling and Madeleine Royale.

Question 14

Define hybrid

Answer 14

Hybrid is a vine whose parents come from two different vine species. Typically, hybrids will have at least one American vine as a parent. They are mainly used for rootstocks. Occasionally they are used for winemaking e.g. Vidal Blanc in Canada.

Question 15

What is Phylloxera and what does it do to vines?

Answer 15

Phylloxera is an insect native to North America. During part of its life cycle, Phylloxera lives underground and feeds on the vine roots of V. Vinifera. Infections enter through the feeding wounds. Eventually the vine is weakened and dies.

Question 16

How are American vines resistant to Phylloxera?

Answer 16

American vines are resistant to Phylloxera. They inhibit the underground louse by clogging its mouth with a sticky sap. They also form protective layers behind the feeding wound preventing secondary infections.

Question 17

Name areas which don’t have Phylloxera.

Answer 17

Chile.
Parts of Argentina.
Parts of South Australia.

Question 18

What are nematodes?

Answer 18

Nematodes are microscopic worms which feed on vine roots. This can limit nutrient and water uptake. Sometimes, nematodes can transmit vine viruses such as Fanleaf.

Question 19

Why graft vines?

Answer 19

Originally to combat Phylloxera. Vitis vinifera can be grafted onto the rootstock of an American vine or hybrid. This gives the protection of American vine and flavour of European vine. Now there are other reasons. Specific rootstocks can be used to protect against nematodes, provide better resistance to drought conditions and grow in specific soils. For example, in Chile, which has Phylloxera-free soils, they use drought tolerant rootstocks.

Question 20

Define grafting

Answer 20

Grafting is a technique used to join a rootstock (usually a North American vine) to a Vitis vinifera variety. There is bench grafting and head grafting. The technique was developed after Phylloxera wiped out European vines (V. vinifera) in the 19th century and from the desire for a Phylloxera resistant vine with grapes from V. vinifera.

Question 21

Describe bench grafting

Answer 21

Bench grafting is an automated process carried out by specialist plant nurseries. Short sections of cane from the V. vinifera variety and rootstock variety are joined together by machine and stored in a warm environment. The two parts then fuse together. The resulting vine can be planted. Once planted, it will take a minimum of 3 years to produce a commercial crop.

Question 22

Describe head grafting

Answer 22

Head grafting is a grafting technique, used in an established vineyard, in which an existing vine is cut back to its truck. A bud or cutting of the new variety is grafted onto the truck, which has an established root system. If successful, the new vine will produce fruit of the new variety the year after the grafting.

Question 23

Why would a grower use “head grafting”?

Answer 23

A grower would use “head grafting” to switch to a different grape variety between seasons in an established vineyard. It is used to make quick adjustments to changes in market demand. It is quicker than replanting a whole vineyard which would need old vines pulling out and replanting new vines. Newly planted vines would then take a minimum of 3 years to produce a commercial crop. In addition, it is cheaper than replanting a whole vineyard and utilises an established root system.

Question 24

Name the main sections of a vine

Answer 24

1. Green parts of the vine (shoots, leaves, buds, tendrils, flowers or berries).
2. One year old wood.
3. Permanent wood.
4. Roots.

Question 25

Define photosynthesis

Answer 25

Photosynthesis is the process by which plants use chlorophyll in their leaves and sunlight to convert water and carbon dioxide into glucose and oxygen.

Question 26

What is glucose and its use?

Answer 26

Glucose is a sugar, produced via photosynthesis, that is used to support vine growth and make ripe grapes taste sweet.

Question 27

Describe buds

Answer 27

Buds can be described as embryonic shoots and are one of the green parts of the vine. They form in the join between the leaf and the shoot. Once formed, they mature inside their casing during the growing season. So at the end of the year, each bud contains in miniature all the structures that will become the shoot, leaves, flowers and tendrils the following year.

Question 28

Describe tendrils

Answer 28

Tendrils are one of the green parts of the vine. They help support the vine. When a tendril senses that it has touched a supporting structure, like trellis wire, it will wind itself tightly round the wire to keep the shoot upright.

Question 29

Describe flowers

Answer 29

Flowers are the vine’s reproductive organs and have both male and female parts. They are grouped in bunches called inflorescences. Each pollinated flower becomes a berry. so each inflorescence becomes a bunch of grapes.

Question 30

Why are grapes sweet?

Answer 30

Grapes are sweet so that they are attractive to animals which then eat the grapes and disperse the vine’s seeds.

Question 31

Describe one year old wood

Answer 31

One year old wood is a shoot that turned woody during the winter after it has grown. Typically it is pruned in the winter to short spurs (with 2-3 buds) or long canes (with 8-20 buds) which determines the crop for the following year.

Question 32

Describe cane

Answer 32

Cane is one year old wood with 8-20 buds and long.

Question 33

Describe spur

Answer 33

Spur is one year old wood with 2-3 buds and short.

Question 34

Describe permanent wood

Answer 34

Permanent wood is wood that is more than one year old. It is made up of the trunk and, where present, arms (cordon) of the vine. Its configuration varies.

Question 35

What do roots do?

Answer 35

Roots:

1. Absorb water and nutrients from the soil.
2. Anchor the vine.
3. Store carbohydrates for the winter.

Question 36

What’s another word for variety?

Answer 36

Cultivar