Viticulture Flashcards
Most common species of vine
Vitis Vinifera
Vitis Lambrusca
Vitis Riparia
Vitis Berlandieri
Vitis Rupestris
Name parts of vine
Tendril
Lateral Shot
Inflorescence
Leaf
Compound bud
Main Shoot
Cane
What is the lenght of stem between nods called?
Internod
What does stem transport?
Water and solutes (substances dissolved in liquid - minerals and sugars)
Explain compound bud
Also called latent bud
Form in one growing season and break open in the next one
Primary bud opens first (followed by secondary or tertiary if necessary)
Explain prompt bud
Form and break in the same season and produce lateral shoots
Main functions of lateral shoots
Back up if main shoot is damaged.
Additional source of leaves for photosythesis
May have inflorescences (second crop) those ripen later or may be removed.
Explain photosythesis
Stomata (pores) open on underside of the leaves letting water diffuse out and carbon dioxide to enter.
Transpiration - transport of water from soil and roots back to leaves
Stomata closes if vine has water stress
Describe composition of grape berry
Pulp - water, sugars, acids and some aroma compounds and aroma precursors
Skin - high concentration of aroma compounds and precursors, tannins and colour compounds
Seeds - oils, tannins and embryo for new plant
Bloom - waxy coating of skin
Stem
2 kinds of vine propagations - explain
Cuttings - section of vine that is planted and grows as new plant. Can be grafted on selected rootstock and treated in nursery against deseases.
Layering - Establish neighbouring vine’s shoot is buried in the ground. New vine grows on its own roots.
Both methods are geneticaly identical to the parent (vines from seeds are not)
Explain clonal selection
Vines with favourable characteristics are propagated in nurseries by cuttings.
Explain mass selection (Selection Massale)
Grower takes cuttings from best performing vines in his vineyard and propagate them by cuttings (may graft them on rootstock)
Own unique planting material
Increases diversity
Costly in terms of time and labour
Possible spread of diseases (from parent)
New vines from seeds
Cross X Hybrid
Cross - parents from the same species
Hybrid - parents from different species
Dormancy (temperatures, hazards, management)
Below 10 degrees
Below -15 degrees hazard of damage or killing vine
Unusual warm can trigger budburst
Winter pruning
Budburst (temperatures, factors, hazards)
Temperature above 10 degrees
Continental climate advantageous with large winter/summer difference - uniform budburst
Maritime climate caìn be less synchronized
Other factors: temperature of soil (sand warms up quickly) and grape variety
Hazard of frost and cold days
Reasons of low carbohydrate levels in roots from previous season
Excessive leaf removal
Water stress
Mildew infections
High crop loads
Shoot and leaf growth stage (needs)
Stored carbohydrates from previous season
Warmth, sunshine, nutrients and water
Petioles
Base of leaf stalks where new buds develop
Fruitfullness
Number of inflorescenses
Describe pollination
Pollen-lade stamens (consisting of anther and filament) are exposed.
The pollen grains are shed and land on the moistened stigma surface
They germinate, each producing pollen tube
Pollen tubes penetrate stigma and then the ovule in the ovary.
Pollen tube delivers the sperm cells which fertilizes the egg in the ovule
Ovule forms up to 4 seeds
The wall of ovary enlarges to form the skin and pulp of the grape
Conditions for successful flowering
(timing, temperatures
8 weeks from budburst (temperature dependent)
min 17 degrees
sunlight, nutrients, water
adverse conditions: rain, clouds, cold temperatures
Pollen germination needs temperature of 26-32 degrees
Coulure
Grape bunch in which fruit set has failed for high proportion of flowers
Imbalance of carbohydrate levels (low rates of photosythesis - cold, cloudy, hot weather, water stress OR vigorous shoot growth)
Grenache, Malbec, Merlot, Cabernet Sauvignon are the most susceptible
Millerandage
High proportion of seedless grapes in bunch - smaller grapes
lower volume of wine or unequal ripeness
Usually from cold, wet, windy weather at pollination and fruit set
Chardonnay, Merlot are susceptible
Methoxypyrazines
contribute to herbaceous aromas/flavours
Sauvignon Blanc, Cabernet Sauvignon, Cabernet Franc
Xilem
Transport tissue which gets water and nutrients from roots to other parts of plant
Grape berry formation
what is created, what is needed
Tartaric and malic acid
Aroma compounds and precursors (Methoxypyrazines)
Tannins
Water intake is high (too much water can triger leaf growth)
Mid water stress speeds up this stage and reduces size of grapes (better quality)
Veraison
Colour change
growth slows down for few days (lag phase)
Chlorophyll in skin cells is broken down and grapes start to change colour
Due to the systhesis of anthocyanins
Factors influencing ripening stage
Grape variety
Climatic conditions
Management of vine and vineyard (heavy crop loads, excessive shading)
Time of harvest
Ripening stage
Sugar and water accumulate
Acid levels fall (tartaric acid is the same, malic acid drops due to use for respiration during ripening - respiration is slower in cooler regions -higher acidity)
Tannins, colour and aroma compounds and precursors develop
Methoxypyrazines levels drops (unless it is cloudy or grapes are too shaded)
Tannins polymerise - soften
Anthocyanins increase with sunshine and temperatures between 15 and 25
Conditions for photosynthesis
18-33 degrees
sunlight levels that are above one third of full sunshine
Water stress can lead to stop of photosynthesis
Phloem
Tissue which transports sugars from the leaves to other parts of the vine
Transportation by xylem slows down at ripening
Optimal ripeness
Balance of sugar, tannin and aroma ripeness
Geen shoot lignification
Becoming woody and rigid - from one-year-wood to cane
Optimum temperature for fruit set
26-32 degrees
Anthocyanin synthesis
definition and temperatures
development of colour
optimum temperature 15-25 degrees
The effects of sunshine
Needed for photosynthesis
reduction of methoxypyrazines
accumulation of tannin before veraison and polymerization after
creation of aroma compounds and precursors
increased use of malic acid for respiration - lower acidity levels
terpenes
Fruity and floral aromas
Grapey aromas in Muscat
Polymerisation of tannins
softening, less bitterness
Influence of latitude
Lower lattitudes - more and stronger solar radiation
radiation travels through less atmosphere and falls on larger angle (stronger)
Hours of sunshine during the year are more stable
higher sugar, lowe acidity, riper aromas, higher but riper tannins, more colour intensity
Lattitude for growing grapes
Between 30 and 50 on each side of Equator
How much temperature falls each 100m?
by 0.6 degrees
Diurnal range
difference between day and night temperatures
Effect of altitude
Cooling influence in high altitude
Sunshine is more intense in high altitude
Ultraviolet radiation is also greater (promotin anthocyanins and tannin synthesis)
High diurnal range
Effect of diurnal range in high altitude
Air absorbs some energy and warmth from the soil and some heat is retained at night.
At high altitude air is thinner and holds less moisture, therefore heat rapidly escapes leading to cool nights.
Slope aspects with the most sun exposure
South for nothern hemisphere
North for southern hemisphere
Importance of aspect and steepness of slope
Increased importance in higher latitudes because solar radiation hits Earth in low angle.
The slope increases the angle therefore increasing the intensity of heat and light
Extention of growing season
In warm climates it may be desirable to limit the heat - planting on slopes which face away from sun
East facing vineyards benefit from morning sunshine (less moisture, longer hours of vine growth)
Shallower and better drained soils with less nutrients
Shelter from winds, rain and frost
Danger of soil erosion
Effect of proximity of water
Water heats up and cools down slower than dry land
Day - water remains relatively cool and lowers the temperature in the area. Cool air from above water is drawn to the land to replace the warm air as it raises, resulting in cool humid afternoon breezes
Night - water retains the warmth and keeps local area warmer
Cold/warm ocean currents
Radiation reflection from the water surface (especially high latitude vineyards)
El Nino
Climatic cycle which occurs every 3-7 years
Pacific Ocean becomes warmer and causes a lot of rainfall and risk of hurricanes in South America and California
Pacific Northwest (Washinghton, Oregon) get warmer than average conditions and drought
Australia and Western side of Pacific - warm and drought
La Nina is the oposite
Effect of wind
cooling or warming influence
Cooling breezes near to body of water (moderating diurnal range)
Valleys - stronger winds (possibility of funnelling between mountain ranges)
Warm breezes from winds travelling over hot land
Reduction of humidity (fungal diseases)
Increase of evaporation rate (increse of need of water)
Hazard of damage by wind (rows of trees as windbreakers on sides of vineyards)
Soil and temperature
Free draining soils (sand, stones) warms up quick in spring - encouraging early budburst and longer growing season (spring frost hazard)
Warm soils encourage root growth (ability to absorb more water and nutrients)
Light coloured soils (chalk) reflect some of energy from solar radiation
Dark coloured soils absorb more energy and re-radiate it when temperatures are cooler (at night)
Mist, fog and clouds
Mist is formed by tiny drops of water colecting in the air above ground or water. It is formed when warm air is rapidly cooled, causing water vapour in the air to condense
Regular cloudy weather can slow down sugar accumulation and acid degradation (beneficial in warm climate for early ripening varieties)
Increase humidity - fungal diseases or noble rot
Annual water need for vine
500mm in cool climate
750mm in warm climate
What is water in vine needed for
For turgidity (so it does not wilt)
Photosynthesis
Regulating temperature
Solvent for nutrients from soil
Healthy growth and ripening
Explain transpiration
Water vapour diffuses out of the stomata (pores underside of leafs)
The water loss causes water to be pulled from the soil
Stomata
Little pores underside of the leaves which vapour water
Lets carbon dioxide an oxyget diffuse in and out
Over supply or under supply of water
Under-supply
stomata closes to save water. Photosynthesis stops, growth stops
Grape shrivelling before harvest (or under-ripe grapes)
Over-supply - vigour (good in spring)
Problem in mid summer as it prolongs and compromise ripening
Excessive shading
Diluting of sugar in grapes before harvest (or even grape splitting)
reduced formation of anthocyanins, tannins and aroma compounds, less tannin polymerisation and higher level of methoxypyrazines
Humid conditions due to poor ventilation
Problems of excessive vegetative growth
vigour (good in spring)
Problem in mid summer as it prolongs and compromise ripening
Excessive shading
Reduced formation of anthocyanins, tannins and aroma compounds, less tannin polymerisation and higher level of methoxypyrazines
Humid conditions due to poor ventilation
Water and soil
Soil drainage and water retention depends on structure and texture of soil
water logged soils are harmful to wine (reducing the amount of oxigen for roots which slows growth)
Warm soils speed up bud burst (longer season)
Slopes - shalower soil with less nutrients, less water due to run off from the slope, problem with erosion
What is evaporation rate and what does it depend on
Amount of traspiration from the wine combined with the evaporation of water from the soil
Depends on temperature, humidity and wind
Nutrients
Nitrogen
Potassium
Phosphorus
Calcium
Magnesium
Sulfur, manganese, boron, copper, iron, zinc
Nitrogen
Component of proteins and chlorophyll (essential for photosynthesis)
essential for vine growth, impact on vigour and grape quality
High levels - excessive vegetative growth (hindering ripening, fruit shading, poor ventilation)
Low levels - reduced vigour (yellowing of leaves) grapes can be difficult to ferment
Restricted supply procudes higher quality grapes
Potassium
Essential for vine growth and water flow
High levels - problems with uptake of magnesium (reduced yields and poor ripening) high potassium in grapes (high pH in wine)
Low levels - low sugar accumulation, reduced yields and poor growth
Phosphorus
Important for photosynthesis
(only needed small amount and usually sufficient)
Low levels - poorly developed root system (poor water intake, low yields, reduced growth)