D1.C2. The Vine Growth Cycle Flashcards
What is the aim of a grape grower?
To produce the largest possible crop of grapes that are of suitable ripeness and quality for the style of wine being produced.
Dormancy period is between which months?
November-March in northern hemisphere
May-September in southern hemisphere
Under what temperature, the vine goes dormant?
Air temperatures below 10°C (50°F)
How does the vine sustain itself during the dormancy?
By using the carbohydrates, mostly starch, accumulated during the previous season in the roots, trunk and branches
What are the adverse conditions which might affect vines during dormancy?
- Unusually high temperatures
- Extreme cold temperatures. Vines can be severely damaged or killed by temperatures below −20°C (–4°F). Temperatures below −25°C (−13°F) will kill most V. vinifera
Budburst period is between which months?
March-April in northern hemisphere
September-October in southern hemisphere
What does the vine need during the budburst?
Average air and soil temperatures above 10°C (50°F)
What are the adverse conditions which might affect vines during budburst?
- Frosts
- Cold soils
What kind of regions are advantageous for successful budburst?
Regions that have marked differences in temperature between the various seasons (for example, continental climates)
What are the disadvantages of maritime climates during budburst?
- Due to less contrast between winter and spring temperatures budburst can be less synchronised.
- Unusually mild winter days cause early budburst; any cold days and frosts that follow can potentially harm the newly burst buds, leading to lower yields
Why are free draining soils like sand advantageous in cool climates?
They tend to warm up more quickly than water-storing soils, such as clay-rich soils, and therefore growing
season starts early which improves the chance of ripening
Name 4 early budding grape varieties
- Chardonnay
- Pinot Noir
- Merlot
- Grenache
Name 3 late budding grape varieties
- Sauvignon Blanc
- Cabernet Sauvignon
- Syrah
Name one human factor which can delay the budburst, and its aim
- Carrying out winter pruning late in the dormant period
- To avoid spring frost
Shoot and leaf growth period is between which months?
- March–July in the Northern Hemisphere
- September–January in the Southern Hemisphere
What does the vine need during the shoot and leaf growth?
- Stored carbohydrates
- Warmth
- Sunlight
- Nutrients
- Water
What are the adverse conditions which might affect vines during shoot and leaf growth?
- Low carbohydrate levels (caused by conditions in the previous growing season)
- Water stress
What does “vine vigour” refer to?
Vegetative vine growth, which includes the growth of the shoots, leaves and lateral shoots, and has implications on the yield and ripening of the grapes
Name the factors that affect the vine vigour?
- Natural sources available (temp, water, nutrients)
- Planting material (variety, clone and rootstocks)
- Presence of any disease
What are the reasons for low carbohydrate levels in a vine?
- Excessive leaf removal
- Water stress
- Mildew infections
- Excessively high yields in the previous growing seasons
Why is water stress is disadvantageous during shoot and leaf growth?
- It can limit photosynthesis and shoot growth
- Nutrient uptake through the roots is also impaired in very dry soils
Flowering and fruit set period is between which months?
- May–June in the Northern Hemisphere
- November–December in the Southern Hemisphere
What does the vine need during the flowering and fruit set?
- Warm temperatures (minimum 17°C/63ºF)
- Sunlight, warmth, water and nutrients for bud fruitfulness in the next growing season
What are the adverse conditions which might affect vines during flowering and fruit set?
- Rain
- Cloudy weather
- Windy weather
- Cold temperatures
What are the factors that can limit bud fruitfulness in the following season?
- Shading of the compound buds
- Low temperatures (under 17°C/77ºF)
- Water stress
- Nutrient deficiency
Why is Riesling well-suited to cool climates?
It is able to form potentially fruitful buds at relatively low temperatures
What is “pollination”?
The pollen grains are shed from the anthers of the stamens and land on the moistened stigma surface
How are the pollen tubes produced?
By germination of pollen grains in stigma surface
How are the sperm cells delivered to the ovary?
By pollen tubes which penetrate the stigma and then the ovule
What does the ovule and the ovary give rise to when fertilized?
- Ovule: Seeds (up to 4)
- Ovary: Skin and the pulp of the grape