Irrigation and Balanced Ripening

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Irrigation and Balanced Ripening

• March 2007

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Irrigation and Balanced Ripening

• Can we manage for ripeness at lower sugars?

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Leaf Water Potential View of Recovery
14 bars
14 bars
Irrigation
12 bars
Stress
Stress
Irrigation
Stress
Recovery
Recovery
10 bars
9 bars
9 bars
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Root Health View of Recovery
Stress
Recovery
Irrigation
Stress
Recovery
Irrigation
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Irrigation Delays Drying Trend
Month of August
Irrigation
Irrigation
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Plant Water Stress is Not Reversible!

• As water stress builds, roots die or become
  non-functional
• Irrigation management needs to take the whole
  season into perspective
• If you wait too long to irrigate, the vines cant
  handle stress later
• Budgeting water stress potential

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Root Dynamics
Low winter rainfall area root system
High winter rainfall area root system
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Big Drink
Roots drink the easy water first, making ABA as
the roots work harder and harder to drink from
greater depth
Long irrigation moves the water down
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Hormone Factories

• Genes in the berry control ripening
• Hormones/signals activate those genes
• Manage the roots and the canopy as hormone
  factories
• Allow stress to develop at key times
• Shoot lignification
• Pre-veraison
• Pre-harvest

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Ripening Signals - ABA

• During lag phase ABA advances onset of veraison
• During ripening ABA stimulates synthesis of
  phenolic compounds
• Synthesized as a response to either shorter days
  or water deficit

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Ripening Signals - Brassinosteroids

• Newly discovered to be important for grape
  ripening
• Released in response to root water, pest, or
  disease stress
• Play a role in initiating and promoting grape
  berry ripening

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Ripening Signals - Ethylene

• Late season water deficit stimulates ethylene
  production
• Increases accumulation of phenolics in the berry
• Triggers leaf abscision
• The last stage of ripening

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Harvest Ethylene Kicking In
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A Functional Canopy?

• Only 2 of carbon fixed by the plant goes to make
  the important phenolics (phenylpropanoid
  metabolism )
• Lignin
• Tannins
• Anthocyanins
• How green do the leaves need to be?
• Shoots lignify when vines are under high stress
• Wine phenolics are made with the same pathway

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Controlled Landing
Harvest
Balanced vines ripen with sugars and flavors in
sync
Too green fruit ripens at high sugars
Too weak crashes before negative characters
disappear
Phenological Timeline
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Balanced Ripening

• Perhaps rethink need for green functional
  canopy at harvest
• Guide vines to the harvest balance point
• Right canopy condition at the right time
• Balance vines with appropriate stress

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Free ET Calculator and CIMIS DD Data

• www.premierevit.com
• Click free tools
• Register as a user

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Steve Matthiasson [phone]
(mobile) steve_at_premierevit.com
855 Bordeaux Way, Suite 100 Napa, CA 94558 (707)
261-8750