D1-VITI Quiz on Natural Factors in the Vineyard

Question 1

What is the name of the mostly widely known, Eurasian grape vine species?

Answer 1

Vitis Vinifera

Question 2

What are the four most important native North American vine species used in viticulture?

Answer 2

Vitis Labrusca
Vitis Riparia
Vitis Berlandieri
Vitis Rupestris

Question 3

What are the 7 parts of a vine shoot at flowering, from ‘bottom to top’?

Answer 3

Cane
Main shoot
Compound buds
Leafs
Inflorescences
Lateral shoots
Tendrils

Question 4

What are the names for the two methods of vine propagation that produce vines that are genetically identical to the parent vine?

Answer 4

Cuttings

Layerings

Question 5

Briefly describe the processes of Clonal and Mass selection. What are the advantages/disadvantages of either approach?

Answer 5

CLONAL SELECTION is the process of taking a cutting from a single parent plant and propagating vegetatively over time to create a new plant that is genetically identical to the parent.

Advantages: Management of the vineyard may be easier if the vines ripen at a similar time.
Clonal selection checks vines for viruses, so vines are virus free

Disadvantages: Reduces diversity in the vineyard and in the fruit which may produce wines that are less complex.
The same plant in one area could lead to high disease pressure as there may be no or little resistance to certain diseases or pests.

MASS SELECTION is carried out by taking cuttings from certain vines that display desired characteristics which can include high quality fruit, high disease resistance, etc. This process takes many years as monitoring of how the vine grows and the wines produced from the grapes are assessed until the vines produce what the grower is looking for.

Advantages: It increase diversity in the vineyard and potential wines due to the plants coming from the growers’ own vineyard.

Disadvantages: Costly and time consuming to produce a new plant. The new plant is not guaranteed virus free.

Question 6

The pulp of most grapes is colourless. However, some grapes have red-coloured pulp. What is the term used for grapes with red pulp?

Answer 6

Teinturier

Question 7

When the two parent vines used to create a new grape variety are from the same species, how is it called?

Answer 7

Crossing

Question 8

When the two parent vines used to create a new grape variety are from different species, how is it called?

Answer 8

Hybrid

Question 9

Are the following varieties crossings or hybrids: Müller-Thurgau, Vidal, Pinotage?

Answer 9

Müller-Thurgau : Crossing
Pinotage : Crossing
Vidal : Hybrid

Question 10

Match the seasons to the events that take place in a vine’s growth cycle:

1. Flowering, pollination, fertilisation
2. Budburst
3. Dormancy
4. Grape development

Answer 10

1. Early summer
2. Spring
3. Winter
4. Late summer

Question 11

During the growing season, vines produce and store carbohydrates. Which carbohydrate is primarily used to support a vine’s growth during dormancy?

Answer 11

starch

Question 12

From March–July in the Northern Hemisphere and September–January in the Southern Hemisphere, carbohydrates stored in the roots, trunk and branches support initial shoot growth of the vine. However, if levels of carbohydrate are low, shoot growth can be negatively affected. Briefly describe what factors may cause carbohydrate levels to be lower than required and what impact these issues might cause.

Answer 12

Carbohydrates levels can be low in the vine due to the previous year’s cultural manipulations including excessive leaf removal. Leaves are a source of carbohydrates, therefore this canopy management technique needs to be clearly understood by the grower before being carried out so as not to unnecessarily deplete the vine.

Cropping the vine very heavily can use up some of the carbohydrates stored in the trunk and roots leaving less available in the following growing season and weakening the vine in the longer term.

Water stress has a major impact on photosynthesis, a lack of water will result in the stomata closing to preserve the water in the vine. This will affect carbon dioxide not being able to enter the plant and stopping or reducing photosynthesis. As a consequence, the amount of carbohydrates will be reduced and thus depleting the store.

High levels of disease that affect the green parts of the plant e.g. downy and powdery mildew attack the leaves. This will reduce the level of photosynthesis, thus reducing the store of carbohydrates available to the vine.
For more information please read Chapter 2 of the D1 textbook on The Vine Growth Cycle.

Question 13

What temperature range is required for successful pollen germination?

Answer 13

26–32°C

Question 14

Briefly describe the process of vine pollination. Be sure to include details on the anatomy of a vine flower, and how the plant develops grapes once fertilised.

Answer 14

1. An inflorescence contains individual flowers, when these open it is described as flowering.
2. Each flower contains pollen laden stamens (anther and filament) which become exposed during flowering.
3. Pollen will disperse and land on the receptive stigma surface, this is referred to as pollination.
4. If germination is successful, pollen tubes grow.
5. Pollen tubes penetrate the stigma and the ovule in the ovary, delivering the sperm cells which fertilise the eggs in the ovule.
6. Formation of the berry occurs, the fertilised ovules form the seeds and the wall of the ovary swells, forming the skin and pulp of the berry.

Question 15

How do you call a condition of the grape bunch in which fruit set has failed for a high proportion of flowers?

Answer 15

Coulure

Question 16

How do you call a condition of the grape bunch in which there is a high proportion of seedless grapes?

Answer 16

Millerandage

Question 17

What is the name of the type of aroma compound that develops during grape berry formation and often contributes toward herbaceous flavours and aromas?

Answer 17

Methoxypyrazines

Question 18

What is the name of the tissue that transports water and some nutrients from the roots to the grapes and other parts of the vine?

Answer 18

Xylem

Question 19

During which period of the growth cycle does the lag phase occur?

Answer 19

Véraison

Question 20

What process causes tannins to become less bitter during ripening?

Answer 20

Polymerisation

Question 21

Name the three main parameters that are often used to determine grape ripeness.

Answer 21

1. The level of sugar in the grapes.
2. The aroma/flavour profile.
3. The ripeness of the tannins.