Learning outcomes Flashcards
What is the definition of pruning?
Pruning is defined as the removal of living shoots, canes, leaves and other vegetative parts of the vine. Summer pruning is removal of the shoots through the growing season. This series of lectures will discuss pruning during dormancy; winter pruning.
What are the six aims of pruning?
To unify vine size and form
This helps to facilitate vineyard operations
To adjust the number of buds (nodes) per vine.
This helps to control crop (yield) and shoot vigour
To select buds which produce fruitful shoots.
Fruitfulness depends on bud position
To distribute buds optimally
To ensure that fruitful buds are retrained and to facilitate training systems. To create a good microclimate
To produce growth stimulating effect of cutting
Hormones produced in the area of the cut stimulate growth
To grow large vine frameworks.
To direct growth in a particular direction, eg setting up a pergola system.
Lable the parts of the vine anatomy
What are the Principles of Pruning (Winkler)
Based on concepts of vigour and capacity?
Pruning reduces vine capacity by removing both buds and stored nutrients in canes.
Production of crop depresses capacity of vine for the following year
Capacity increases with number of shoots that develop (but non-linear). Total leaf area not vigour, important for capacity.
Shoot vigour varies inversely with number of shoots and crop.
Extremes in vigour do not favour fruitfulness (Fig 79 Winkler et
al 1974).
A cane of large size has greater capacity, but buds may be less fruitful
Capacity limited by previous history and environment.
What happens to whole crops compared to pruned vines?
- Retaining whole crop leads to only 37% growth depression
- Non-pruned vines have a greater capacity for crop production than normally and severely pruned vines.
- Pruning decreases potential for crop production and growth.
Define the tearms Vigour and Capacity
Vigour: measure of rate of shoot growth
Capacity: the total amount of growth (amount of dry matter) produced in a season; fruit, shoots, leaves, roots and increment of old wood.
Classification of pruning systems
Based on arrangement of old wood.
- Maybeshortspur: 1-2nodes
- Long spur: 3-5 nodes
- Canes: 6-20 nodes
What are the benifits of Spur pruning?
- Pruning to two node spurs results in stimulus from pruning cut most strongly to a distance of about 2 nodes. Two nodes limits extension of vine framework.
- Spurs do not always need to be 2 nodes and distal rather than proximal shoot can be kept (depending on direction).
- Two versus more nodes depends on degree of apical dominance in the variety and fruitfulness of basal buds.
Draw the diagram of a spur cut
What are the mian aspects to consider when cane pruning?
- Usually head trained (may arise from cordon, eg Sylvoz and hanging cane)
- 1-8 canes per vine
- long bearers 8-15 nodes long, with 2 node replacement
- spur per cane.
- Suits most varieties
- Problem with apical dominance, terminal shoots burst and develop at expense of nodes in the middle of the cane, get shoots developing near the trunk (Jackson’s end point principle), arching canes or application of hydrogen cyanamide solve the problem.
How do you select the canes to keep?
- internodes 6-8 cm,
- brown colour to tip,
- diameter 6-8 mm (pencil dia),
- rounder rather than flatter internode (selection for exposed canes rather than shaded canes)
What are the advantages and disadvantages of cane pruning compared to spur pruning?
- Cane pruning: easier to adjust node number (and yield), eg leaving shorter or longer canes. On spur pruned vines to reduce node number spur positions need to be removed.
- Cane pruning is more expensive
- Varieties and/or Cool/cloudy conditions, cane pruning can give higher yield because basal buds are less fruitful
- More CHO removed with cane pruning because 2-yr old wood is removed
How can pruinin control yield?
- Limiting number of nodes/vine and type of buds available to burst.
- Degree of budburst from nodes may vary and this depends on the type of pruning, time of pruning and variety.
- Factors that determine yield components occur in both the previous and current season.
- Pruning can indirectly affect all the ratios in the above relationship via
When is the optimal time to prune and why?
- Anytime from leaf-fall till bud burst; after budburst no significant translocation of reserves from shoot to roots.
- Time of pruning before budburst has some effect on time of bud burst and subsequent stages (see Martin and Dunn 2000).
- If sap flows from cut, this does not seem to have an effect.
- Prune after buds have started to move, can delay bud burst for up to 2 weeks; can assist in avoiding adverse weather at a critical phenological stage. (eg frost at budburst)
- Summer pruning (trimming slashing): a canopy management tool for improved fruit composition and disease control, used in hotter districts to delay fruit maturation to improve composition (flavour and aroma), but reduces yield by 50-60%.
What is the definition of pruning level?
- Quantified as the number of nodes left after pruning.
- May be expressed as nodes/vine, nodes per metre of row, nodes per metre of canopy, node/unit area of vineyard surface.
- For typical wide row (3m):
- Severe pruning: less than 20 nodes per metre of row
- Moderate: 20-75 nodes per metre of row
- Light: greater than 75 nodes per metre of row.
