Grape and Wine Science

What is the geographic origin of Vitis vinifera L.?

The area around the Black Sea and the inland Caspian Sea, bordering Iran, Georgia, Armenia, and Azerbaijan.

How did the transition from nomadic to sedentary communities impact grape cultivation?

The intentional cultivation of grapes occurred in parallel with this transition.

Who is credited with spreading grape cultivation to the coastlines of North Africa and the Iberian Peninsula?

The Carthaginians and Phoenicians.

Which ancient civilization's temples contained grape harvesting illustrations similar to those in Egypt?

The Minoan civilizations of Crete and the eastern Aegean islands.

Where were the first vineyards of Gaul (France) likely planted?

In Marseilles, by Greek settlers around 500 BC.

Why did European vines fail in eastern North America?

Due to phylloxera, various foliar diseases, and the cold winter climate.

What invention by Dr. Nathaniel Bagshaw Ward facilitated the transport of plants overseas?

The Wardian case, a glass container that maintained humidity and protected plants.

What was the primary negative consequence of using Wardian cases for plant transport?

They inadvertently harbored insects and diseases from North America, which then plagued European botanical gardens.

What treatment was discovered to control powdery mildew (Uncinula necator Burr)?

Sulphur.

What treatment was discovered to control downy mildew?

Copper sulphate.

Which pest caused the most significant destruction to European vineyards in the 19th century?

Phylloxera.

When did commercial grape production begin in the Niagara Peninsula and south western Ontario?

In the late 1880s.

What was the purpose of the Ontario Liquor Commission organized in 1933?

To control wine production and monitor the quality and sanitation procedures of wineries.

What was the significance of the French grape varieties introduced to Ontario in the 1950s?

They combined native North American bloodlines for pest resistance with superior European flavor profiles.

What are the three primary climatic constraints on commercial grape growing?

Winter hardiness, ripening capability, and availability of water.

Within what latitude range is commercial grape growing generally constrained?

Within the 50th parallel of latitude, north and south.

What are the typical mean annual isotherm and growing degree day (GDD) requirements for grapes?

10-20 degrees Celsius and 1000-3000 growing degree days.

What is the ideal climate for Vitis vinifera L.?

Mediterranean climates characterized by hot, dry summers and cool, wet winters.

Who standardized the plant classification system using genus and species names?

Carl von Linne (Linnaeus).

What is the botanical classification of grapes at the Class level?

Angiosperm.

What is the botanical classification of grapes at the Subclass level?

Dicotyledons.

What is the botanical classification of grapes at the Order level?

Rhamnales.

What is the botanical classification of grapes at the Family level?

Vitaceae.

How many subgenera are within the genus Vitis?

Two: Euvitis and Muscadinia.

What are the primary characteristics of Proles occidentalis grapes?

They are centered in eastern and northern Europe, possess winter hardiness, can ripen in cool/short seasons, and are fertile with high sugar and acid levels.

Which proles of grapes is considered the origin of many table grapes and is characterized by large, loose clusters with often seedless, oval berries?

Proles orientalis.

What is the primary use for grapes from the Proles pontica group?

Drying.

What components make up the aerial portion of a grapevine produced within the present year?

Shoots with leaves, clusters, and tendrils.

What is the difference between a prompt bud and a latent bud?

A prompt bud produces the summer lateral during the current season, while a latent bud produces the fruiting shoot in the following season.

What is the function of the primary bud within an overwintering latent bud?

It is responsible for the main shoot and is usually fruitful.

Under what conditions are the smaller buds in the axils of prophylls typically activated?

Only during extreme conditions of cane or trunk loss.

What are the two major divisions of the grapevine vascular system?

Phloem and xylem.

What is the primary function of the phloem in a grapevine?

Translocating the products of photosynthesis throughout the plant.

What is the primary function of the xylem in a grapevine?

Moving water and dissolved minerals from the roots up through the plant.

What layer of actively dividing cells is responsible for the origin of both phloem and xylem?

The cambium.

What is the function of the cork cambium?

It produces cells that become the periderm, which is the brown outer skin of the cane.

How is a vine's preparedness for winter gauged?

By the degree of periderm formation on the present season's shoots.

What is the zone of absorption in a grapevine root?

A section around 100 mm long behind the zone of elongation, covered in root hairs, where water and minerals are absorbed.

What substances give the older parts of a grapevine root system their brown color?

Waxy, waterproof depositions called suberin and oxidized phenols.

What is the typical leaf venation pattern in grapevines?

Palmate venation, where veins emerge from a central point in a hand-shaped pattern.

Why can the leaf lamina fall before the petiole?

Because leaves have two distinct abscission zones: one between the lamina and petiole, and another between the petiole and shoot.

What are the three developmental stages of grape berries after fruit set?

Stage 1: Cell Division, Stage 2: Lag Phase (seed hardening), and Stage 3: Cell Expansion.

How long does the standard process of producing hardwood cuttings take?

Approximately 14 months.

What is the purpose of grafting a scion onto a rootstock?

To combine the desired fruit characteristics of the scion with the environmental tolerance (e.g., phylloxera, salinity, drought) of the rootstock.

What is the Omega graft technique?

A method of matching and cutting the scion and rootstock wood to fit together, usually in an upside-down Omega (Ω) shape.

What is the primary risk when planting green potted vines compared to dormant hardwood cuttings?

Green potted vines are subject to rapid water loss and temperature shock, requiring irrigation for successful establishment.

What is field grafting (or top working)?

Planting rootstock rootings in the permanent vineyard site and grafting the scion onto them later via T-budding or chip budding.

How are new grape varieties improved through controlled breeding?

By emasculating a mother plant, pollinating it with a father plant, collecting the seeds, and then vegetatively propagating the best resulting vines.

What is clonal selection in viticulture?

The process of identifying and propagating a vine that has developed a valuable mutation compared to its neighbors.

What is anoxia in the context of grapevine roots?

Waterlogged, airless soil conditions, typically induced in the winter.

What is the function of root hairs?

They are elongated epidermal cells that greatly increase the surface area for the absorption of water and minerals.

What are the two types of buds found at the base of the leaf petiole?

Prompt buds and latent buds.

Why do annual growth rings appear in the xylem of a grapevine?

Because xylem cells vary in size, being larger in the spring and smaller in late summer.

What is a plant clone in the context of viticulture?

An individual vine propagated separately from a parent vine to maintain specific traits like berry size, cluster orientation, or ripening differences.

Which three elements are most common in organic plant units?

Carbon, hydrogen, and oxygen.

What is the primary role of magnesium in plant physiology?

It is the central component of chlorophyll.

Which element is crucial for the ion pumping mechanism that controls stomata?

Potassium (K+).

What is the function of Boron in plants?

It assists in the translocation and loading of sugars and photosynthates into the phloem.

How does the pH scale function regarding acidity and alkalinity?

It is a logarithmic scale where each unit change represents a 10-fold change in concentration.

What is the primary structural component of plant cell walls?

Cellulose.

Where do light reactions of photosynthesis occur within the plant cell?

Inside the chloroplasts.

In which cellular organelle do respiratory reactions take place?

The mitochondria.

What is the function of the plasmodesmata?

They facilitate communication between plant cells.

How does light wavelength relate to energy level?

As the wavelength shortens, the energy level increases.

What is the chemical equation for photosynthesis?

6CO2 + 6H2O + Light Energy → C6H12O6 + 6O2.

What is the role of chlorophyll P680 in photosynthesis?

It traps red light energy to enable the splitting of water, releasing electrons and oxygen.

What are the two primary energy-transfer compounds produced during the light-dependent reactions?

ATP and NADPH.

What occurs during the 'dark cycle' or carbon fixation?

Energy (ATP and NADPH) is used to fix carbon into complex molecules like sugars and starches without requiring light.

What is the primary purpose of respiration in plants?

To convert fixed carbon into energy transfer units (ATP and NADH) for growth and development.

What determines the direction of carbon partitioning in a vine?

Sink strength, which prioritizes areas of high metabolic demand such as growing shoots, roots, or fruit.

When does fruit development typically receive priority for carbon partitioning?

In late summer.

What is phenology?

The study and description of the growth cycle stages of a plant.

What is 'véraison' in viticulture?

The beginning of the ripening stage, marked by the softening and colouration of the fruit.

What distinguishes temperate zone perennials from tropical evergreen species regarding dormancy?

Temperate perennials undergo a period of dormancy with no active photosynthesis, while tropical species are evergreen and shed leaves asynchronously.

How do plants survive during dormancy?

They rely on stored starches in perennial organs to fuel low levels of respiration.

What is the role of iron in plant energy reactions?

It acts as a critical catalyst in energy reactions and chlorophyll synthesis.

What is the function of the endoplasmic reticulum in plant cells?

It serves as part of the communication system within the cell.

What primary environmental factors trigger flowering in most seed plants?

Day length and light intensity.

How do temperate zone plants differ from tropical plants regarding flowering triggers?

Temperate plants require greater changes in day length and are also influenced by temperature changes.

When does flower cluster initiation begin in grapevines?

During the bloom of the previous year's flowers.

What is the significance of the axillary bud's exposure to light?

Exposure to light influences the fertility of the bud; leaves developing in the shade result in less fruitful latent axillary buds.

What is 'millerandage' in grape development?

A condition where incomplete fertilization leads to berries of uneven sizes, often appearing as 'hens and chicks'.

Define 'coulure' in the context of grape flowering.

A condition where very poor fertilization causes infertile ovaries to fall, leaving only a few berries on the cluster.

What are 'shot berries'?

Berries that grow without seeds but do not fall from the cluster.

How does boron deficiency or nitrogen toxicity affect grapevines?

They can cause set failure or rachis failure, where the stem holding the cluster turns brown and dies during ripening.

How does rain during bloom affect grapevines?

It prevents or delays pollination.

What effect does pruning have on the overall capacity of a grapevine?

Pruning has a stunting effect; it reduces the plant's ability to store carbohydrates, resulting in a smaller plant with less capacity.

How does a large crop in one season affect the vine's capacity for the following year?

A large crop depletes carbohydrate reserves, depressing shoot growth and reducing the vine's capacity to bear fruit in the next season.

What is the relationship between the number of shoots and the vigor of individual shoots?

The vigor or rate of growth of a shoot varies inversely with the number of shoots and the amount of crop on the vine due to carbon partitioning.

What three factors determine a grapevine's fixed capacity in any given season?

Leaf area, the carbohydrate balance of the previous season, and the present environment.

Why is it important to remove extra fruit in cool, rainy summers?

To improve color and sugar accumulation in the remaining fruit.

What is the purpose of deficit irrigation during stages II and III of berry development?

To restrict berry size, which is considered a quality improvement for wine grapes.

What factors determine the harvest time for table grapes?

The drop in acidity and the accumulation of sugar to a point where the grapes are pleasant to taste.

Beyond sugar and acid, what factors are critical for determining the ripeness of wine grapes?

The ripeness of flavors, tannins in the seeds, absence of bitterness in the skins, and flesh flavor.

What happens to flower clusters during the winter months?

They remain as developing clusters within the dormant winter bud.

What is the effect of waterlogged soils in the spring on grapevines?

It impairs growth and delays flower cluster development.

What is the primary physiological principle behind pruning woody perennials?

Carbohydrate partitioning; removing plant parts removes substantial carbohydrate reserves.

How does the number of retained buds/nodes relate to harvest prediction?

The approximate final harvest can be predicted based on the total number of buds/nodes retained on a dormant cane.

What are the risks of a vine carrying too much fruit?

Detrimental effects on fruit quality (low sugars, delayed harvest), reduced capacity for the next season, and increased risk of winter injury.

What is the critical period for vine activity in eastern North America?

May through July.