,WSET Diploma D1 Study Guide 2025/2026:
Vine Biology, Viticulture, and Winemaking
Essentials.
Most important North American grape species
Vitis labrusca, Vitis riparia, Vitis berlandieri and Vitis rupestris
Four main sections of a grape vine
the main shoots, one-year-old wood, permanent wood and the roots
What comprises the canopy of a vine?
The main shoots and all of their major structures - stem, buds, leaves, lateral shoots, tendrils
and inflorescences/grape bunches
What do the main shoots grow from, and when?
The main shoots on the vine grow in spring from buds retained from the previous year
Where are carbohydrates stored in a vine?
Stems, trunks, roots
Define lignify
Green shoots become woody and rigid, they are then called canes
Where do buds form?
between the leaf stalk (petiole) and the stem
Define the two types of buds
- Compound buds (form in one growing season and break open the following growing season,
producing main shoots; typically a primary, secondary, and maybe tertiary)- Prompt buds (form
and break open same season, form lateral shoots)
- Prompt buds (form and break open same season, form lateral shoots)
What is the main function of lateral shoots? When are they desirable/undesirable?
- to allow the plant to carry on growing if the tip of the main shoot has been damaged or eaten
- can provide an additional source of leaves for photosynthesis (useful if the laterals are near the
ends of the main shoots)
,What is second crop?
Lateral shoots often produce inflorescences, which can be known as a 'second crop'
- Growth of laterals nearer the base of the main shoot can be undesirable as they impede air
flow and can shade the fruit too much
What is green harvesting?
Removal of second crop during summer
Define one-year-old wood
the main shoots from the last growing season that were kept at pruning, supports compound
buds; cane or spur
Define permanent wood
woody parts of the vine that are older than one year, including the trunk
where are most roots found?
top 50cm of soil
what distinguishes PN clone 115?
low yield, small grapes, good for high quality of red wines
what distinguishes PN clone 521?
high yield, bigger grapes, good for sparkling wine production
When is leaf fall and dormancy?
Nov-March
When is budburst?
March-April
When is shoot and leaf growth?
March-July
When is flowering and fruit set?
May-June
When is grape development?
June-Oct
, When is harvest?
Sept-Oct
How does the vine support itself during dormancy?
starch in the roots, trunk, and branches
Below what temp can vines be severly damaged? die?
-15C, -25C
What factors determine the timing of budburst?
- air temp (>10C)
- soil temp (higher encourages earlier budburst)
- variety
- human factors (e.g. winter pruning late -> later budburst)
Why is high continentality good for budburst?
marked differences in temp can result in uniform budburst
what determines the vigor of a vine?
rate of shoot growth
when does the fastest rate of shoot growth typically occur?
between budburst and flowering
what could cause low carb levels in roots, trunk, and branches?
- excessive leaf removal
- water stress
- high crop loads in prev season
what can slow initial shoot growth rates?
low carb levels
what supports shoot growth in later stages?
photosynthesis
at what point of the vine growing cycle is water stress not desired?
late stages of shoot growth (can affect photosynthesis)
what can stunted shoot growth lead to?
Vine Biology, Viticulture, and Winemaking
Essentials.
Most important North American grape species
Vitis labrusca, Vitis riparia, Vitis berlandieri and Vitis rupestris
Four main sections of a grape vine
the main shoots, one-year-old wood, permanent wood and the roots
What comprises the canopy of a vine?
The main shoots and all of their major structures - stem, buds, leaves, lateral shoots, tendrils
and inflorescences/grape bunches
What do the main shoots grow from, and when?
The main shoots on the vine grow in spring from buds retained from the previous year
Where are carbohydrates stored in a vine?
Stems, trunks, roots
Define lignify
Green shoots become woody and rigid, they are then called canes
Where do buds form?
between the leaf stalk (petiole) and the stem
Define the two types of buds
- Compound buds (form in one growing season and break open the following growing season,
producing main shoots; typically a primary, secondary, and maybe tertiary)- Prompt buds (form
and break open same season, form lateral shoots)
- Prompt buds (form and break open same season, form lateral shoots)
What is the main function of lateral shoots? When are they desirable/undesirable?
- to allow the plant to carry on growing if the tip of the main shoot has been damaged or eaten
- can provide an additional source of leaves for photosynthesis (useful if the laterals are near the
ends of the main shoots)
,What is second crop?
Lateral shoots often produce inflorescences, which can be known as a 'second crop'
- Growth of laterals nearer the base of the main shoot can be undesirable as they impede air
flow and can shade the fruit too much
What is green harvesting?
Removal of second crop during summer
Define one-year-old wood
the main shoots from the last growing season that were kept at pruning, supports compound
buds; cane or spur
Define permanent wood
woody parts of the vine that are older than one year, including the trunk
where are most roots found?
top 50cm of soil
what distinguishes PN clone 115?
low yield, small grapes, good for high quality of red wines
what distinguishes PN clone 521?
high yield, bigger grapes, good for sparkling wine production
When is leaf fall and dormancy?
Nov-March
When is budburst?
March-April
When is shoot and leaf growth?
March-July
When is flowering and fruit set?
May-June
When is grape development?
June-Oct
, When is harvest?
Sept-Oct
How does the vine support itself during dormancy?
starch in the roots, trunk, and branches
Below what temp can vines be severly damaged? die?
-15C, -25C
What factors determine the timing of budburst?
- air temp (>10C)
- soil temp (higher encourages earlier budburst)
- variety
- human factors (e.g. winter pruning late -> later budburst)
Why is high continentality good for budburst?
marked differences in temp can result in uniform budburst
what determines the vigor of a vine?
rate of shoot growth
when does the fastest rate of shoot growth typically occur?
between budburst and flowering
what could cause low carb levels in roots, trunk, and branches?
- excessive leaf removal
- water stress
- high crop loads in prev season
what can slow initial shoot growth rates?
low carb levels
what supports shoot growth in later stages?
photosynthesis
at what point of the vine growing cycle is water stress not desired?
late stages of shoot growth (can affect photosynthesis)
what can stunted shoot growth lead to?
