what is the name of the part of the grapevine that runs horizontally?
cordon
what is the technical name for the grapevine? and how long ago was it domesticated?
Vitis vinifera
approx 7000 years ago
what is the average temp range that grapevines can grow in?
12-22
what are the benefits of North-South trellising row orientation?
highest light penetration… peaks in the morning and afternoon
what are the benefits of east-west trellising row orientation?
lowest interior canopy interception.
peaking just after midday
what are 3 different types of trellising options?
vertical shoot positioned
smart Dyson trellising
Scott Henry
what are the irrigation options available to viticulturalists
drip irrigation - most common overhead sprinkler irrigation subsurface irrigation under-vine sprinkler furrow irrigation
what are the two main ways to grow vines?
cuttings (new vineyard) top grafting (old vineyard)
describe the steps of establishing a new vine/yard using the cuttings technique. make reference to when in the year this happens.
“starting from scratch”
- from the dormant vineyard (June/July), canes are cut
- canes are then nurtured to develop roots and leaves
- these plants are then looked after indoors away from elements, giving them a chance to harden
- they may then move outside, but still undercover to further harden
- they are planted in a new vineyard
describe the steps of establishing a new vine/yard using the top grafting technique.
changing the grape variety of an existing vineyard
- the trunk of the vine is cut off, just below the crown so there is still a substantial amount of trunk
- prepare the top of the trunk
- insert bud/cutting of the desired variety
- wrap the area where the cut was made/bud inserted
- wait for new canes to grow
why are rootstocks used?
- pest or disease tolerance e.g. phylloxera
- climate tolerance - drought
- control growth - less vigour
- soil tolerance - salinity
what percentage of the world’s vineyards are planted on rootstocks?
90
in the grapevine life cycle, when does bud burst take place?
what happens and how?
September
new growth starts from the reserves of carbohydrates stored in the roots.
Water starts to be “taken up”
in the grapevine life cycle, when does shoot growth take place?
what happens and how?
October - November
- after budburst, there is a new shoot and then leaf growth
- photosynthesis begins
- crop estimation by flower count is now possible
- this is a critical time of vulnerability from disease, stress (lack of water) and Frost
in the grapevine life cycle, when does flowering and fruit set/canopy management take place?
what happens and how?
Nov-Dec
- vines use photosynthesis to grow and ripen fruit, converting sunlight to sugar
- the optimum range for efficiency is 15-30 degrees
what is canopy mgmt used for during nov/dec and how does it happen?
leaf plucking, hedging and crop thinning can be used to modify inception of sunlight to the grapes by essentially pruning the vines.
- also, fruit can be thinned (cutting away some of the bunches) to increase the quality of the remaining fruit
in the grapevine life cycle, when does veraison take place?
what happens and how?
- this is simply ripening that normally takes place around 40-50 days after fruit set
- flavour develops
- sugars trade-off with acids
during veraison, how does colour change occur?
due to chlorophyll in the berry skin being replaced by anthocyanins (in red wine grapes)
carotenoids (white wine grapes)
in the grapevine life cycle, when does harvest take place?
what happens and how?
can take place between Feb and April - the ideal month is march
- berries start to soften as they build up sugars
- sugars (glucose and fructose) accumulate and acids begin to fall
what are the optimum sugar and ph readings for grapes to be harvested?
12-14 baume
3.6 pH
why would a winery want to pick early?
to get the grapes as sweet as possible but without losing all the acidity
in the grapevine life cycle, when does Senescence take place?
what happens and how?
April - May
senescence is the leaves browning and falling. this happens because after fruit harvest, photosynthesis continues creating carbohydratereserve to store in the vine’s roots, and once these are full, photosynthesis stops
in the grapevine life cycle, when does dormancy take place?
what happens during this period?
May-august
in this period, no water is taken up by the roots
- as they have no leaves, no photosynthesis occurs.
- no water or fertilisation is needed as the vine uses its reserves of carbs in the trunk to survive
- the best time for pruning as the vine is least susceptible to stress
why is pruning so important?
pruning and training control growth of canopy and amount of fruit for the following season
- number of buds left per cane = number of new shoots = number of bunches
