Winter Pruning Flashcards
5 goals of winter pruning
*Maintain a canopy shape suitable to cultural practices
* Regulate vegetative growth
* Retain enough fruitful nodes
*Regulate cluster number and their size
*Producing grapes of the desired quality
First 3 principles of winter pruning
- Pruning reduces vine capacity
- Crop level reduces vine capacity
- Fruitfulness relates to shoot vigor
Last 3 principles of winter pruning
- Shoot vigor is inversely correlated to shoot number and yield
- The grapevine self-regulates
- Shoot direction influences shoot vigor
Any time we do winter pruning in a given vine and environment regardless of the pruning type, we are regulating 3 things:
- Number of cropping units (spurs, buds)
- Length of cropping unit
- Position of each cropping unit
What is the vine capacity graph showing?
that every time we winter prune, we are reducing either yield potential and vine capacity.
What is the difference between vine capacity and vine vigor?
Vine capacity = total leaf area
Vine vigor = speed of growth, cane weight, single cane growth
Explain each point of the table:
Weak weak
Weak strong
Strong weak
strong strong
Weak weak: is the case of a small plant of 1 year old or a poor vine, very weak.
Weak strong: the case of mechanical pruning, because we are leaving on several nodes and so each shoot will grow a little.
Strong weak: the case of a young vine during the training phase showing just few shoots very vigorous, but the leaf area is still low.
Strong Strong: a bit rare, but a plant with several shoots and each of those shoots is very vigorous.
What are the three modalities of winter pruning?
- Hand
- Mechanical (with or without hand follow up)
- “Minimal”
What kind of pruning is this?
Guyot
What kind of pruning is this?
Spur pruned cordon
The main factor that has to drive us towards Guyot or spur pruning is…
Which do we do for high and low fruitfulness?
Basal bud fruitfulness
For high fruitfulness we can do spur pruning
For low fruitfulness we can do guyot
Discuss this situation and the 2 advantages and 2 disadvantages
This is what the simonit guys do for spur pruned cordon
advantages:
- Vascular system is healthier
- smaller wounds and less chance of disease
Disadvantages:
- Because we are moving farther and farther away from the cordon we lose space for canopy
- If we bank on this situation and remove all other vegetation and we dont get the growth that we want we may be hosed for the season (risky)
What is CV?
CV is the coefficient of variation
What does the CV show us when we compare shoot position and leaf area with guyot and spur?
We can see that guyot has a much higher variation of leaf area per shoot according to the position of the shoot on the cane
When spur pruning never ever exceed…
3 count nodes
Mechanization with guyot could be problematic because…
You could shorten the cane that you would use for the next year depending on the length of the cane and the length between vines.
If well conducted, short pruning should lead to…
More uniform shoot growth, hence ripening.
With which training system did mechanical winter pruning begin?
GDC (Geneva double cordon)
What is GDC?
It is a horizontally spilt canopy with spurs, the canopy is free as a type of sprawl canopy.
_________ is a regulating factor for the vine.
Bud break rate
What is the minimal goal that would make you happy with Mechanical winter pruning?
I want to save time, I dont have skilled workers, I also would be happy if I would get the same yield and the same quality. I cant pretend I can increase quality, but maybe I can get a similar yield and similar quality, saving time and money
What are they doing?
performing the hand finishing to prune everything left under the cordon, where the machine doesn’t work.
When you increase the nodes/vine we also get a…
Decrease in Bud Break
With MMP - LF we get? (4)
Medium mechanical pruning - long finish
When should we absolutely not do this?
- higher nodes/vine
- lower bud break(shoot/node)
- a decrease in overall quality
- an increased yield.
To do this with a high basal bud fruitfulness would be worse…
What is minimal pruning?
Not winter pruning, only summer pruning
Self regulation prevents…
overcropping and vine exhaustion
What are the three advantages of minimal pruning?
- In spring there is a much bigger canopy so there is higher light interception, and earlier photosynthetic activity
- Lots of shoots with low vigor, they reach around half meter of length and then they stop, so it means that still at flowering there’s no competition with the inflorescences, ideal condition for ripening.
- Technique allows to get much more clusters, but definitely smaller, loser and with small berries
4 considerations with minimal pruning
- Increased Yield
- Yield tends to vary from year to year (barely controlled)
- Quality can be acceptable
- Best adapted to Med climates. Too cool and we can have delayed ripening and botrytis
What is “fence” pruning or semi-minimal pruning?
A modified version of minimal pruning that is best adapted to wet conditions
What are the findings with fence pruning? (5)
- Yield was slightly higher
- Higher brix
- Higher color
- Less botrytis
- Mechanical harvesting works better
Considerations with wood diseases with pruning spur vs guyot (3)
- It is not really about the size of the cut, but how many cuts we make, so spur can be worse for wood diseases.
- It also depends on the weather and if its cold and wet after we cut the scarring will be slowed
- We should perform winter pruning later as also to avoid frost damage
