4. The vine

Question 1

Nearly all grapes used to make wine is the species ….

Answer 1

Vitis vinifera

Question 2

What are the factors affecting the grape growers while selecting a grape variety?

Answer 2

• Budding and ripening times

- Resistance to diseases

Question 3

What are the two methods to propagate vine

Answer 3

• Cutting

- Layering

Question 4

Which method is preferred most? Cutting or layering? Why?

Answer 4

Cutting. Because there is Phylloxera risk in layering because it takes place in the vineyard

Question 5

What is a clone?

Answer 5

Each individual vine or group of vines that shows a particular set of unique characteristics

Question 6

What is clonal selection?

Answer 6

Selection of vines with positive mutations for further propagation so that positive characteristics of these vines can be carried forward in new plantings

Question 7

What is cross-fertilization?

Answer 7

Pollen from the male part of the flower of one one is transferred to the female part of the flower of another vine (same species) and the pollinated flower develops into a grape with seeds. If the seed is planted and grows, then it is a new variety

Question 8

What is crossing?

Answer 8

A new grape variety, produced from the same species of vine. Technically all grape varieties used today are crossings but this term is reserved for the varieties bred by researchers

Question 9

Give 2 examples of crossings:

Answer 9

• Müller-Thurgau: Riesling x Medeline Royale

- Pinotage: Pinot Noir x Cinsault (Hermitage in SA)

Question 10

What is hybrid?

Answer 10

A vine whose parents come from two different vine species

Question 11

Why are the hybrids and American vine crossings important?

Answer 11

They are used throughout the world as woodstocks

Question 12

How does Phylloxera affect the vine?

Answer 12

Phylloxera has a very complex life cycle (18 phases). In one phase, it lives underground and feeds on the root of vines.

Question 13

How does the American vine species protect themselves from Phylloxera?

Answer 13

• By clogging their mouth by a sticky sap

- By forming protective layers behind the feeding wound

Question 14

Which regions of the world are free of Phylloxera?

Answer 14

• Chile
• Some parts of Argentina
• South Australia
• Canary Islands

Question 15

Besides resistance to Phylloxera, what are the other advantages of American rootstocks?

Answer 15

• Protection against nematodes

- Resistance to drought

Question 16

What are the two types of grafting techniques?

Answer 16

• Bench grafting: Joining a rootstock to a Vitis Vinifera variety
• Head grafting: Existing vine is cut back to its trunk and a bud or cutting of a new variety is grafted onto the trunk

Question 17

When do the grape growers use head grafting technique?

Answer 17

When they want to switch to a different grape variety between seasons

Question 18

What are the sections of a vine plant?

Answer 18

• Green parts ( Buds, tendrils, leaves, flowers and berries)
• One-year-old wood
• Permanent wood
• Roots