Anatomy of the vine, vine species, grape species, vineyard management, diseases
What are the 2 main species of vine?
- Vitis vinifera
- North American Vines (3 chief species):
- Vitis labrusca
- Vitis riparia
- Vitis rupestris
What is phylloxera?
- A fungal disease
- A viral disease
- A North American root louse
A North American root louse.
Of the two main vine species, which one is more resistant to phylloxera?
How does it protect itself?
North American vine species are more resistant to phylloxera. It is for this reason American rootstocks are widely used across the world.
The North American vine protects itself from phylloxera by seeping a sticky sap that inhibits the louse from eating, and the vine generates a defensive layer behind a wound which prevents the louse from damaging the plant material further.
Are there any places in the world today that remain free of phylloxera?
Yes, the major ones are:
- Some areas in South Australia and Argentina
Of the two main vine species, which is the most widely used around the world for quality wine production?
Vitis vinifera is most used for fine wine grape growing in the world.
The grape varieties we all know by name are from the Vitis vinifera family, such as Sauvignon Blanc, Chardonnay, Pinot Noir, Zinfandel, Syrah, and Cabernet Sauvignon.
What are some primary differences between Vitis vinifera and North American vines?
- known to have more desirable aromas for wine
- considered to produce higher-quality grapes for the production of fine wine
North American vines:
- more resistant to pests and diseases than vinifera
- generally better suited to extreme climates than vinifera
What are 2 different ways a vine can be propagated?
- Cutting - when a section of a shoot is cut off from an existing vine and is planted in order to grow a brand new plant. It’s done mostly in nurseries;
- Layering: A vine’s 1 year-old cane is bent into the ground and partially buried with the tip of the cane poking out above ground; the buried part grows roots and establishes itself as a new plant. It takes place in the vineyard.
What is clonal selection?
When a vine naturally mutates and its new, positive characteristics are propagated by cutting or layering.
Grafting is a procedure used to fuse budwood of a desired variety (usually V. vinifera) onto another rootstock (usually a North American vine).
This technique was discovered to be both useful and necessary after phylloxera decimated European vineyards in the mid-to-late 1800s. The idea is to have a phylloxera-resistant vine that produces V. vinifera.
What are some of the benefits of grafting onto American rootstocks?
- American rootstock protects against phylloxera while giving ability to produce V. vinifera grapes;
- North American rootstocks are found to be resistant to nematodes, drought, and alkaline soils, unlike V. vinifera.
What is head grafting and why is it used?
Head grafting is when a vine’s top, or head, is cut off its trunk and the cutting of a new variety is grafted on to the trunk where the old head was.
The purpose of head grafting is to switch out grape varieties instead of uprooting and replanting an entire vineyard. Head grafting will produce fruit the year after the grafting, and it’s a lot less expensive than replanting an entire vineyard with the added bonus of keeping the established trunk and roots.
How are new grape varieties created?
What is cross-fertilization?
Name a few reasons why a viticulturist might want to cross-fertilize.
Cross-fertilization is when a viticulturist takes the pollen from the male part of one vine’s flowers and fertilizes the female parts of a different vine’s flowers to create a new grape variety.
The cross-fertilized flowers will grow into grapes, which will have seeds. Those seeds are collected, later planted, and if those seeds grow into a viable plant, a new grape variety is born.
Reasons to cross-fertilize:
- To create a disease resistant variety;
- To adapt the new grape to climate extremes or drought;
- To increase quality or yields.
What is the difference between crossings and hybrids?
Crossings: when a new grape variety is created by crossing parents of the same vine species, e.g. Cabernet Sauvignon (Sauvignon Blanc x Cabernet Franc - both V. vinifera).
Hybrids: when at least two different vine species, usually a North American vine and a vinifera vine, are crossed to create a brand new vine species, e.g. Concord and Vidal Blanc (only 1 parent is V. vinifera).
What is the crossing of Cabernet Sauvignon?
Cabernet Franc x Sauvignon Blanc
What is the crossing of Müller-Thurgau?
Riesling x Madeleine Royale
What is the crossing of Pinotage?
Cinsault x Pinot Noir
What are the 4 main parts of a vine?
- Permanent wood
- 1 year-old wood
- Green parts (also known as the canopy: leaves, grapes, tendrils, etc.)
Explain the importance of a vine’s leaves.
Leaves are what drive the plant’s growth.
Via photosynthesis, leaves use sunshine to convert water and CO2 into the things it needs to grow: glucose and oxygen.
What is transpiration?
Transpiration is the process of how water is absorbed by a vine’s roots, transported throughout the plant, and out of its leaves in vapor form.
The warmer the climate, the faster water evaporates from the leaves, which means the vine needs more water from the soil.
To get really nerdy, read more about transpiration here.
What are tendrils on a vine and what is their role?
Tendrils are a vine’s support system so that it stays upright (or attached to a trellising system).
What are the buds on a vine?
Where are they found?
Buds contain and will become the following year’s green parts (tendrils, flowers, leaves, shoot).
Buds are primordial shoots found between a shoot and a leaf.
What is 1-year-old wood (aka a cane)?
The previous year’s shoot
The buds on last year’s shoot will be the 1-year-old wood’s shoots, tendrils, and leaves.
What is permanent wood on a vine?
Wood that is more than 1 year old:
- arms / cordons (if there)
What are the functions of a vine’s roots?
- Absorb water + nutrients which they send up the plant
- Anchor the vine in the soil
- Store carbohydrates over winter to keep the vine alive
What are the “reproductive organs” of a vine?
Flowers have both male and female parts, and vines’ flowers self-pollinate. Each pollinated flower then turns into a grape.
What is inflorescence?
Clusters of flowers (before they actually become flowers).
Inflorescences will eventually become flowers which then transform into grape clusters.
Photo courtesy of WSET.
What is the difference between a cane and spur?
They’re both 1 year-old wood from the previous year’s growth. However, the main difference between them is how many buds each has.
Cane: a long woody branch with 8 to 20 buds
Spur: a short woody branch with only 2 to 3 buds
What are some important factors to consider when deciding where to establish a new vineyard?
- Environmental/Climate considerations
- location and aspect of proposed vineyard
- soil type/fertility, drainage, average sunlight/rain, temperature
- Trade/Business considerations
- how remote is the vineyard?
- how easy will it be to find employees or help at harvest?
- Which grape(s) to plant?
- which varieties suit the climate?
- is there demand for the grape(s)?
- any legal restrictions?
What are the 2 main types of vine training?
- Head training
- Cordon training
Describe head training.
- Usually just a trunk (not a lot of other permanent wood)
- Some have just a few short “arms” of permanent wood growing out of the top of the trunk
Describe cordon training.
- More permanent wood than head trained;
- A trunk with usually one or two permanent arms or “cordons”;
- Usually spur-pruned (spurs look like “fingers” growing out of the arm/cordon, see photo);
- Mechanized harvesting easier.
The removal of undesirable canes, leaves, and permanent wood.
When are vines pruned?
What are the purposes of summer pruning?
- Control the canopy, which…
- Forces sugar production in the grape instead of the vine directing that energy to expand the canopy;
- Give grapes favorable sun exposure via leaf stripping.
In regions with powerful sunlight, what risk is there if the canopy is deleafed too much during summer pruning and exposing the grapes to that intense sunlight?
Sun burn, which will lead to off-flavors
What are the purposes of winter pruning?
- To choose the number + location of buds that will form shoots in the upcoming growing season;
- Ensure buds are not too close to each other (this helps with next year’s canopy management).
What are the 2 styles of winter pruning?
- Replacement cane
Spur pruning can be found on what type of vine training?:
- Head trained
- Cordon trained
- Both head and cordon trained
Both head and cordon trained
Replacement cane pruning is most often found on what type of vine training?:
- Head trained
- Cordon trained
- Both head and cordon trained
What are trellises, or a trellising system?
A system of permanent stakes (wood or metal) with wires that support the vine for its annual and seasonal growth.
The wires can also support canes and cordons.
3 reasons to use a trellising system instead of Bush vines:
- Control the amount of sunlight that gets into the canopy;
- Improve air circulation for the leaves and grapes;
- Positioning grapes and leaves improve mechanical harvesting + distribution of any sprays used.
Give 2 examples of head-trained vines.
Bush (‘untrellised’) vines tend to produce a lush canopy, so they perform best in hot, dry regions such as Jérèz or Southern Rhône where the grapes need the extra shade.
Bush vines are generally head-trained and spur-pruned (meaning, 2-4 buds on each 1 year-old spur).
Guyot vines are generally head-trained and cane-pruned (meaning, a permanent main trunk with 1 cane + a spur [Single Guyot) or 2 canes + spurs [Double Guyot]).
See this article by Caroline Gilby, MW for further explanation on Guyot and Gobelet.
What is a synonym for Bush vines?
Gobelet – so called as it resembles the shape of a wine glass or goblet.
Bush/Gobelet vines are untrellised.