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.
