WSET Diploma D1 Updated Exam 2023
with complete solution
Most important N American grape species Ans- Vitis labrusca, Vitis riparia, Vitis
berlandieri and Vitis rupestris
Four main sections of a grape vine Ans- the main shoots, one-year-old wood,
permanent wood and the roots
What comprises the canopy of a vine? Ans- 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? Ans- The main shoots on the vine
grow in spring from buds retained from the previous year
Where are carbohydrates stored in a vine? Ans- Stems, trunks, roots
Define lignify Ans- Green shoots become woody and rigid, they are then called canes
Where do buds form? Ans- between the leaf stalk (petiole) and the stem
Define the two types of buds Ans- - 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)
What is the main function of lateral shoots? When are they desirable/undesirable?
Ans- - 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)
- 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 second crop? Ans- Lateral shoots often produce inflorescences, which can
be known as a 'second crop'
What is green harvesting? Ans- Removal of second crop during summer
Define one-year-old wood Ans- the main shoots from the last growing season that
were kept at pruning, supports compound buds; cane or spur
,Define permanent wood Ans- woody parts of the vine that are older than one year,
including the trunk
where are most roots found? Ans- top 50cm of soil
what distinguishes PN clone 115? Ans- low Y, small grapes, good for high Q red
wines
what distinguishes PN clone 521? Ans- high Y, bigger grapes, good for sparkling
wine production
When is leaf fall and dormancy? Ans- Nov-March
When is budburst? Ans- March-April
When is shoot and leaf growth? Ans- March-July
When is flowering and fruit set? Ans- May-June
When is grape development? Ans- June-Oct
When is harvest? Ans- Sept-Oct
How does the vine support itself during dormancy? Ans- starch in the roots, trunk,
and branches
Below what temp can vines be severly damaged? die? Ans- -15C, -25C
What factors determine the timing of budburst? Ans- - 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? Ans- marked differences in temp can
result in uniform budburst
Chard, PN, Merlot, Grenache are ______ budding Ans- early
SB, Cab, Syrah are ________ budding Ans- late (need higher temps)
what determines the vigor of a vine? Ans- rate of shoot growth
when does the fastest rate of shoot growth typically occur? Ans- between budburst
and flowering
, what could cause low carb levels in roots, trunk, and branches? Ans- - excessive leaf
removal
- water stress
- mildew
- high crop loads in prev season
what can slow initial shoot growth rates? Ans- low carb levels
what supports shoot growth in later stages? Ans- photosynthesis
at what point of the vine growing cycle is water stress not desired? Ans- late stages
of shoot growth (can affect photosynthesis)
what can stunted shoot growth lead to? Ans- - weak shoots
- reduction in leaf number/smaller leaves
- inflorescences that do not flower properly
what can limit bud fruitfulness? Ans- - low temp (<25C)
- water stress
- shading
- nutrient deficiency
how long after budburst does flowering typically take place? Ans- 8 weeks (temp
dependent)
why are warm conditions (>17C) desired during flowering? Ans- speeds up flowering
(occurs within a few days)
what % of flowers become grapes typically? Ans- 30%
what temp does pollen germination require? Ans- 26-32C
what negatively affects pollen tube growth? Ans- wind, rain, cold temps; wind, water
stress, hot temps
define coulure Ans- A condition of the grape bunch in which fruit set has failed for a
high proportion of flowers. This occurs when ovule fertilisation is unsuccessful, and
therefore no grape develops.
what causes coulure? Ans- imbalance in carb levels due to:
- low photosynthesis rates
- vigorous shoot growth diverting carbs (very fertile soils, vigorous rootstocks)
define millerandange Ans- A condition of the grape bunch in which there is a high
proportion of seedless grapes.
with complete solution
Most important N American grape species Ans- Vitis labrusca, Vitis riparia, Vitis
berlandieri and Vitis rupestris
Four main sections of a grape vine Ans- the main shoots, one-year-old wood,
permanent wood and the roots
What comprises the canopy of a vine? Ans- 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? Ans- The main shoots on the vine
grow in spring from buds retained from the previous year
Where are carbohydrates stored in a vine? Ans- Stems, trunks, roots
Define lignify Ans- Green shoots become woody and rigid, they are then called canes
Where do buds form? Ans- between the leaf stalk (petiole) and the stem
Define the two types of buds Ans- - 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)
What is the main function of lateral shoots? When are they desirable/undesirable?
Ans- - 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)
- 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 second crop? Ans- Lateral shoots often produce inflorescences, which can
be known as a 'second crop'
What is green harvesting? Ans- Removal of second crop during summer
Define one-year-old wood Ans- the main shoots from the last growing season that
were kept at pruning, supports compound buds; cane or spur
,Define permanent wood Ans- woody parts of the vine that are older than one year,
including the trunk
where are most roots found? Ans- top 50cm of soil
what distinguishes PN clone 115? Ans- low Y, small grapes, good for high Q red
wines
what distinguishes PN clone 521? Ans- high Y, bigger grapes, good for sparkling
wine production
When is leaf fall and dormancy? Ans- Nov-March
When is budburst? Ans- March-April
When is shoot and leaf growth? Ans- March-July
When is flowering and fruit set? Ans- May-June
When is grape development? Ans- June-Oct
When is harvest? Ans- Sept-Oct
How does the vine support itself during dormancy? Ans- starch in the roots, trunk,
and branches
Below what temp can vines be severly damaged? die? Ans- -15C, -25C
What factors determine the timing of budburst? Ans- - 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? Ans- marked differences in temp can
result in uniform budburst
Chard, PN, Merlot, Grenache are ______ budding Ans- early
SB, Cab, Syrah are ________ budding Ans- late (need higher temps)
what determines the vigor of a vine? Ans- rate of shoot growth
when does the fastest rate of shoot growth typically occur? Ans- between budburst
and flowering
, what could cause low carb levels in roots, trunk, and branches? Ans- - excessive leaf
removal
- water stress
- mildew
- high crop loads in prev season
what can slow initial shoot growth rates? Ans- low carb levels
what supports shoot growth in later stages? Ans- photosynthesis
at what point of the vine growing cycle is water stress not desired? Ans- late stages
of shoot growth (can affect photosynthesis)
what can stunted shoot growth lead to? Ans- - weak shoots
- reduction in leaf number/smaller leaves
- inflorescences that do not flower properly
what can limit bud fruitfulness? Ans- - low temp (<25C)
- water stress
- shading
- nutrient deficiency
how long after budburst does flowering typically take place? Ans- 8 weeks (temp
dependent)
why are warm conditions (>17C) desired during flowering? Ans- speeds up flowering
(occurs within a few days)
what % of flowers become grapes typically? Ans- 30%
what temp does pollen germination require? Ans- 26-32C
what negatively affects pollen tube growth? Ans- wind, rain, cold temps; wind, water
stress, hot temps
define coulure Ans- A condition of the grape bunch in which fruit set has failed for a
high proportion of flowers. This occurs when ovule fertilisation is unsuccessful, and
therefore no grape develops.
what causes coulure? Ans- imbalance in carb levels due to:
- low photosynthesis rates
- vigorous shoot growth diverting carbs (very fertile soils, vigorous rootstocks)
define millerandange Ans- A condition of the grape bunch in which there is a high
proportion of seedless grapes.
