Chapter 2: The Vine Growth Cycle Flashcards
1.1.3 - Vine's Needs through the Growth Cycle (70 cards)
1
Q
What is the most important aspect of winter pruning?
A
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).
2
Q
Define and describe ‘budburst’
A
3
Q
Define and describe ‘vigor’
A
4
Q
Define and describe ‘flowering’
A
5
Q
Define and describe ‘fruit set’
A
6
Q
Define and describe ‘bud fruitfulness’
A
7
Q
Define and describe ‘pollination’
A
8
Q
Define and describe ‘coulure’
A
9
Q
Define and describe ‘millerandange’
A
10
Q
Define and describe ‘early grape growth’
A
11
Q
Define and describe ‘aroma precursors’
A
12
Q
Define and describe ‘methoxypyrazines’
A
13
Q
Define and describe ‘veraison’
A
14
Q
Define and describe ‘ripening’
A
15
Q
Define and describe ‘extra-ripening’
A
16
Q
What are three factors that influence a vine’s vigor?
A
Available resources for the vine (water, nutrients, temperature)
Vine’s variety, clone and rootstock
Whether disease lives in the vineyard where the vine is planted, which can lower vigor
17
Q
What are three things that can cause excessively low vigor and what is the solution for each?
A
Drought stress - solved by irrigation (where allowed)
Low soil fertility - solved by increased fertilization and drainage
Disease - solved by diagnosis and treatment
18
Q
During what months are vines dormant in the Northern and Southern Hemisphere?
A
Northern: Nov (11) - Mar (3)
Souther: May-Sept
19
Q
Below what temperature do vines go dormant?
A
10ºC (50ºF)
20
Q
At what temperature does freeze injury/damage occur?
A
-20ºC (-4ºF)
21
Q
At what temperatures will most V. vinifera be killed?
A
-25ºC (-13ºF)
22
Q
When does budburst (also known as budbreak) occur in the Northern and Southern Hemispheres?
A
Northern Hemisphere: March - April
Southern Hemisphere: September - October
Budbreak marks the end of winter dormancy
23
Q
What does the timing of budburst depend on?
A
Air temperature;
Soil temperature;
Grape variety;
Human factors.
24
Q
What are the buds that are bursting during budbreak (prompt buds or compound buds)?
What air temperature do they need to burst?
A
Budbreak buds are the compound buds formed in the previous year’s growing season;
The buds need a sustained average air temperature of ~10°C / 50°F.
25
Why do regions that have a marked contrast in their seasonal temperatures (e.g. Continental climate) typically have a greater advantage of homogenous budbreak and subsequent growing phases, and even ripening over regions that have less contrast in their seasonal temperatures (e.g. Maritime climate)?
Rapidly increasing temperatures in the spring mean that the vines benefit from the rise in temperature and are in sync with each other development-wise, whereas a region that has less contrast between winter and spring temperatures can be confusing for the vines, particularly when there are mild days during winter when the vine is supposed to be dormant. This can lead to uneven budburst, and if there’s a frost, uneven yields.
26
Higher soil temperatures around the roots encourage budburst to happen (a) earlier or (b) later
Earlier
Dry, well-draining soils (e.g. sandy soils) tend to warm up more quickly than water-storing soils (e.g. clay-rich soils).
27
What does 'early budding' mean?
Grape varieties, e.g., Chardonnay and Pinot Noir, that require relatively low temperatures at budburst
28
What does 'late budding' mean?
Grape varieties, e.g., Sauv Blanc, Cab Sauv, that require higher temperatures at budburst
29
If vines are winter pruned late in the dormancy period, what can this do to budbreak?
Postpone budbreak
This technique can be used in areas where spring frost is known to be a problem.
30
When do vines have shoot and leaf growth in the Northern and Southern Hemispheres?
Northern Hemisphere: March through June
Southern Hemisphere: September through December
31
When does the fastest rate of vine growth generally occur?
Between budburst and flowering
32
What drives initial shoot growth?
Carbohydrates stored in the vine's roots, trunk, and branches.
33
What stimulates further shoot, leaf, and vine growth?
Photosynthesis, which increases with leave development.
Vine needs adequate warmth and sunlight to photosynthesize.
34
What are the principal nutrients a vine needs to grow?
Nitrogen
Potassium
Phosphorus
35
What are some consequences if a vine experiences stunted shoot growth (which can happen from dry soils, poor nutrient availability, or water stress)?
Small, weak shoots;
Reduction in leaf number or smaller leaves;
Inflorescences that don’t flower properly;
Grape bunches that do not ripen fully, which can lead to poor fruit quality and lower yields.
36
When is flowering and fruit set in the Northern and Southern Hemispheres?
Northern Hemisphere: May–June
Southern Hemisphere: November–December
37
What are some conditions in the present growing season that can limit bud fruitfulness for the next growing season?
Shading of compound buds;
Low temperatures (under 25°C / 77°F);
Water stress;
Nutrient deficiency.
38
How does pollination work?
Pollen grains are shed from the stamen (or anther) and land on the moistened stigma surface.
39
When does flowering take place with regards to budburst?
Within 8 weeks
40
What is fruit set?
Term used to describe the transition from flower to grape.
41
What is the temperature required for successful flowering?
approx 17ºC (63ºF)
42
What happens if there are low temperatures during flowering?
The duration of flowering is lengthened;
The consequence of which is a negative effect on the evenness of ripening.
43
Typically, what percent of flowers become grapes?
30% (it can range from 0-60%)
44
What are the two common forms of irregular fruit set?
Coulure
Millerandage
45
What is couture and what causes it?
A high proportion of failed fruit set in grape bunch (unsuccessful fertilization).
Coulure is caused by an imbalance in carbohydrate levels, and that imbalance can be caused by:
low photosynthesis (cloudy conditions or water stress);
improper canopy management (vigorous shoot
growth diverting carbohydrates
from the inflorescence);
overly-fertile soil.
Some coulure is normal; excessive coulure can reduce yield.
46
What is millerandage and what causes it?
It’s when a high percentage of grapes within a bunch are seedless and, usually, smaller than the normal berries with properly formed seeds;
these smaller grapes can either ripen normally or stay unripe, which can affect the quality of the crop;
Caused by unfavorable weather (cold, wet, windy) at fruit set.
47
When does grape development occur in the Northern and Southern Hemisphere?
Northern Hemisphere: June–September
Southern Hemisphere: December–March
48
What are the four stages of grape development?
Which stage is the most important in determining final grape quality?
Early Grape Growth;
Véraison;
Ripening (most important)
Extra-Ripening.
49
When does berry formation start?
Soon after fruit set
50
What is happening inside the grape during berry formation (early grape growth)?
Accumulation of tartaric and malic acids;
Accumulation of tannins;
Development of aroma compounds and aroma precursors;
High water flow into the grape;
Low sugar levels.
51
What does the vine need during berry formation?
Sunlight;
Warmth;
Mild water stress.
52
What happens if a vine gets too much water and nutrients during the berry formation stage?
Shoot growth is encouraged over grape ripening, which delays the onset of the ripening stage which means that the grapes might not ripen fully in time for harvest
53
Grape varieties with tight bunches, such as Sémillon and Pinot Noir, can be prone to fungal disease. Why?
The possibility of their grape skins splitting during the growth cycle is increased due to the very nature of their tight, compact bunches;
Lack of air flow in the crowded bunches increases humidity, and if the skins split then disease is difficult to avoid.
54
What is véraison?
When grape berries change color signaling the onset of final ripening.
White grapes go from green to yellow, and red grapes go from green to red.
55
What’s happening inside the grape during the ripening stage?
Cells in the grape expand rapidly;
Sugar and water accumulate;
Acid levels fall;
Tannins, color, aroma precursors and aroma compounds develop.
56
How can excessively cloudy or excessively hot and dry conditions affect the ripening stage?
If cloudy conditions, photosynthesis slows and can interfere with sugar accumulation (read: lead to under-ripe grapes);
If hot and dry conditions, photosynthesis slows or can even stop, also interfering with sugar accumulation.
57
In warm, dry conditions grape transpiration (and sugar accumulation) is: (a) faster than in cool, humid conditions, (b) slower than in cool, humid conditions or (c) grape transpiration and sugar accumulation never fluctuate
Faster than in cool, humid conditions
58
Why do wines from cooler climates tend to have higher natural acidity?
Because malic acid is used in respiration during the ripening stage, and respiration is slower at cool temperatures than warm ones.
This is also why cooler nighttime temperatures are important for producing balanced grapes with fresh acidity.
59
During the ripening stage in a normal year, which compound levels increase and which compound levels decrease in the grapes?
Increase:
Aroma compounds and aroma precursors
Anthocyanins
Decrease:
Methoxypyrazine
Tannins (they polymerize)
60
What are the two biggest differentiators in how grapes ripen during the ripening stage?
Heat;
Sunlight.
61
What are four factors that determine the length of the ripening stage?
Grape variety;
Climatic conditions;
Vine and vineyard management;
Time of harvest.
62
What happens inside the grape during the extra-ripening stage?
Sugars accumulate (and water is lost) from grape transpiration
63
What temperature ensures vine dormancy?
Under 10ºC (50ºF)
64
At what temperature do winter freeze and/or damage occur to a vine?
-20ºC (-4ºF)
65
Budburst is stimulated above this temperature.
What else stimulates budburst?
0°C (50°F);
Warm soil temperatures can also stimulate budburst.
66
What is the optimal temperature range for photosynthesis?
18–33°C (64–91°F)
67
What is the minimum outdoor temperature a vine needs for the flowering and fruit set stage?
Minimum 17°C / 63°F
68
What is the optimal temperature range for fruit set?
26–32°C / 79–90°F
69
Warm temperatures (25°C / 77°F) around the time of fruit set promote increased bud fruitfulness for (a) that same year, (b) the next year, or (c) the year after next year
next year
70
What is respiration?
Vines produce energy by combining sugars (from photosynthesis), oxygen, and other compounds with water and carbon dioxide.
During respiration, that energy stored by the vine is released.
