Level 4 D1 Chap 2 - The Vine Growth Cycle Flashcards
Question
Answer
List the phases of vine growth, starting in winter
- Dormancy
- Budburst
- Shoot and leaf growth
- Flowering and fruit set (8 weeks after budburst)
- Grape Development
- Harvest
- Leaf fall (and back to dormancy)
What resources does a vine need to survive?
- Water
- Sunlight
- Warmth
- Nutrients
- Carbon Dioxide (a factor that growers cannot control)
What average temperature gives rise to dormancy?
< 10°C
What temperature kills most vines?
Vitis vinifera is killed below -25°C
Other vines may die at -20°C
What average temperature gives rise to new growth (budburst) in the spring?
Budburst is triggered >10°C
Compare the impact of a continental climate over maritime on budburst
Continental climates: Sharper changes in temperature in continental systems, typically give rise to uniform budburst and ultimately ripening.
Maritime climates: There is a lower risk of frost damage from a cold spell after budburst, but budburst may not be as synchronized. Also a few unusually mild days can bring on budburst…and then a freeze may hit.
Compare the impact of soil water retention on temperature and vine growth
Free draining soils hold less water, and heat up quicker encouraging earlier budburst and potentially earlier ripening.
How and why do growers delay budburst?
Late winter pruning can delay budburst, to help avoid spring frost damage
What does a vine need during its ‘shoot and leaf growth’ phase?
- Carbohydrates (to get growth going)
- Warmth
- Sunlight (for photosynthesis to kick off)
- Nutrients (thru roots)
- Water
What does a vine need to maximise flowering and fruit set?
Current year buds:
- needs a minimum temperature of 17°C
- dry, calm days so that pollen is not washed away from the stigma, and can grow fertilisation tubes
For next year buds:
- sunlight
- water
- warmth
- nutrients
Name and describe the process by which flowers turn into grapes?
Name: Fruit set
Pollen grains land on the stigma and from there grow a tube into the ovary to deliver sperm cells that fertilise the vines eggs.
Fertilised eggs become seeds within grapes, and the walls of the ovary enlarge to form the pulp and the skin.
______ is a condition in which fruit set has failed for a high proportion of flowers.Describe its causes and name a susceptible variety
COULURE is a condition in which fruit set has failed for a high proportion of flowers
It is cause by
- Carbohydrate imbalance
- Low rates of photosynthesis (too cloudy/cold)
- Water stress
- Vigorous vegetative growth competing for resources (too much fertiliser)
Grenache, Cabernet Sauvignon, Merlot, Malbec
What is coulure?
A high failure rate for fruit set
______ is a condition in which there is a high proportion of seedless grapes.Describe its causes and name a susceptible variety
MILLERANDAGE is a condition in which there is a high proportion of seedless grapes.
It is caused by cold, wet weather at pollination and fruit set disrupting the growth of pollen tubes.
Chardonnay, Merlot