Developmental physiology Flashcards
Three aspects of Yield formation
- Cultivar and/or clone bud fruitfulness
- Bud load retained at winter pruning
- Shoot and/or cluster thinning
What is crop load and what is crop level?
- Crop load is a ratio of leaf area to yield
- Crop level is expressed as the number of clusters per vine
top is high capacity
bottom is high vigor
What is overcropping>
when we exceed the potential of the vine and there is not enough carbon to be partitioned
What is vine capacity?
a vine’s total weight of fruits and shoots at the end of season
What is vigor?
The rate of shoot growth (cm/day)
Grapevines have a limited capacity because of limitations imposed by available resources, so…
vines can only support a certain number of shoots and ripen a certain amount of fruits in any one season.
largest yield potential is often achieved on vines of…
Medium vigor
Low light on leaves above and below a bud reduces
bud fruitfullness
What is PAR and why is it important?
PAR is Photosynthetic Active Radiation. When PAR goes below 1/3 of maximum light availability there is a marked reduction in bud fruitfullness.
Severe loss of leaf area can reduce
inflorescence initiation and differentiation
In addition to high light, _____ are required for maximum inflorescence initiation and development
relatively high T
__________ reduces bud fruitfulness; a ___________ might increase it.
- Severe water stress
- moderate water stress
Both block 0 and 1 have low bud induction
Block 2 and 3 have higher bud induction
Flower development and differentiation after budbreak is totally dependent upon stored reserves. This means that…
The amount of reserves stored the previous season is critical for maximum flower formation.
Environmental conditions for flowering are around 17 C anything higher _____ the rate of flowering. The flowering process takes time.
Reduces
Final berry size is determined by…
The number of cell divisions before and after anthesis
What is anthesis?
The period during which a flower is fully open and functional
Do we want larger or smaller berries?
We want smaller berries
