Reproductive Cycle Flashcards
What are 2 ways of reporting phenology assessments?
a single date with average of 50% at phenological stage
multiple dates of when phenological dates occur
anlage
‘starting point’ inside bud; beginning of primiordia for flower cluster or tendril
When does the anlage form?
around flowering time
What is Phase 1 of bud formation?
Induction: about 5 leaf primordia develop and then knobby undifferentiated primordia structures called anlagen that can develop into either tendrils or bunches.
What conditions are needed for anlagen formation?
full sunlight and above 20˚C needed to obtain maximal development of anlagen.
Why does canopy management play a role in the formation of anlage?
Canopy management dictates canopy microclimate which can change the development of the anlage and thus affecting the fertility of the following year.
What is the initiation phase (phase 2) of bud formation?
When anlagen are induced to either form tendrils or flower cluster primordia. It is influenced by light, temperature, and cytokinins. All 3 factors should be optimal to achieve optimal fertility.
What happens when factors for optimal bud development are not sufficiently present?
- The individual flower primordia become smaller and consequently the berries become smaller
- There are fewer flowers on the flower cluster and consequently fewer berries on the bunch
A shoot with 3 bunches will be bigger than a shoot with one bunch. On a the shoot with 3 bunches, the cluster that grew first will be biggest.
What happens in Phase 3 of bud formation?
Around budburst the following spring, the arms of the bunch stalk develop rapidly and the primordia of the male and female flower parts develop. They form individual flowers enfolded by calyptra and together they form the flower cluster.
Climatic conditions at the time of bud burst determine the size of the framework of the bunch stalks (the compactness of the bunch)
What are bracts?
Protection around flowering
What is the timing of bud formation along a shoot?
The basal bud develops first and in 3 day intervals, the following buds are induced.
Induction in buds 8-12 take place 3 weeks to a month after bud one. Later buds are usually more fertile than basal buds due to more advantageous weather.
This could determine cane or spur pruning depending on variety.
Would you do spur pruning on Sauvignon Blanc?
Probably not; With lower fertility, you want to keep a cane with more later formed buds for yield.
Will a frost after bud break eliminate yield?
No; the secondary buds will push
What is bud dissection for?
For deciding pruning. You need a razor and a microscope.
What is another way of determining how many buds to lay down?
Single node cuttings; cut a node off and place in hole with water. Remove leaves to preserve resources; Note the inflorescences for fertility. Note which bud number they come from due to variation in fertility.
What is the rule of thumb for berry weight at veraison?
berry weight at veraison is roughly half the weight of berries at harvest
Why is May/June important for good climate conditions? (for determining yield)
It is the development of the clusters for next year and the current year’s flowering and growth.
When is a good time to count infloresncences?
When there are not too many leaves to sift through; in May
What percentage of flowers develop into berries?
30%
Why should you spray before bunch closure?
To ensure the spray goes inside to where the botrytis is sitting on dead flowers.
When should you green harvest?
as soon as possible; do it before veraison
Why green harvest?
If there is too much fruit hanging, you do not want to drain your resources; and to fully ripen the berries you leave.
What happens if you do leaf removal before flowering?
Less photosynthesis; less fruit set
What could you do to keep canopy open, light, and warm for fertility in the buds?
VSP, Scott Henry, Make sure you don’t have too much vigor that shades canopy.
Do bud rubbing and shoot thinning to open up canopy.
Why don’t you want too much rain during flowering?
The caps will stick and you won’t have proper pollen tube growth.
What is a good indication for veraison?
Softness
Why should you note the length and diameter of node cuttings?
it is an indication of vigor
