In viticulture, the canopy of a grapevine includes the parts of the vine visible aboveground - the trunk, cordon, stems, leaves, flowers, and fruit. The canopy plays a key role in light energy capture via photosynthesis, water use as regulated by transpiration, and microclimate of ripening grapes. [1] Canopy management is an important aspect of viticulture due to its effect on grape yields, quality, vigor, and the prevention of grape diseases. Various viticulture problems, such as uneven grape ripening, sunburn, and frost damage, can be addressed by skillful canopy management. [2] [3] In addition to pruning and leaf trim, the canopy is often trained on trellis systems to guide its growth and assist in access for ongoing management and harvest. [4]
The vine is the main part of the grapevine, extending from the root system in the ground up to the cordons, or arms, of the vine. When the grape is young the trunk is very pliable and must be supported by stakes as part of a vine training system. The height of the trunk varies depending on grape variety and the type of trellis system being used and can range from 4 inches (10 cm) to 30 feet (10 m). During winter dormancy, the trunk can be vulnerable to extreme freezing conditions and will be sometimes buried and insulated with soil to protect it. [5]
The trunk is composed of sleeves of conductive tissue, most notably the phloem and xylem. The outside bark of the vine contains the phloem tissues which transports sap, enriched by sugars and other molecules, from the leaves to the rest of the vine. During the annual growth cycle of the grapevine, the vine will start to store carbohydrate energy in the wood part of the trunk and roots. The downward passage of phloem sap to the roots and this storing process can be interrupted by the viticultural practice of "girdling" or cincturing the vine. This process can improve fruit set by forcing the vine to direct most of its energy towards developing the grape clusters. The xylem is the woody tissue on the inside of the trunk that moves sap, enriched with water, minerals and other compounds, up from the roots to the leaves. [5]
The cordon, or "arms", of the grapevine extend from the trunk and are the part where additional arms and eventually leaves and grape cluster cordons are usually found along wires as part of a trellis system. This training usually fixes the cordon into a permanent position, such as horizontal extending from the trunk in opposite directions. [6]
The terms stem, stalks and shoots are sometimes used interchangeably but viticulturalists generally make some differentiation. The stem of the grapevine item, extending from cordon, is considered the shoot and this part is most often pruned in the process of "shoot thinning" to control grape yields. The stalk extending out to hold the grape cluster is known as the bunchstem while the stem of the individual grape berry is the pedicel. [7]
The shoot of the vine develops from new buds located on the cordon and grow to include the leaves, tendrils and eventually grape clusters. Shoots first begin to appear in spring, following bud break, accelerating growth till the flowering stage and usually slowly by the time that the vine begins veraison. During the stage of veraison (typically mid to late summer), the shoot starts to harden and change color from green to brown.
The shoot is ripening at this point and becomes known as a "cane." In wintertime, the canes of the grapevine are usually completely cut off with the amount and weight of the cane being used to gauge the amount of pruning and canopy management that will be needed for the upcoming year. The "tip" of the shoot is the small (0.4 in/1 cm) part of the shoot furthermost from the vine. Viticulturalist use the growth of this tip as an indication of vine vigor because the tip competes with the grape clusters for resources from the vine. Ideally, shoot growth should come to a stop around the time of veraison; a vine that continues growing the shoots will stand the chance of less fully developed grape clusters. [8]
A grapevine's leaves are the most visible part of the canopy and also one of the most important. It is through the leaves that the vital physiological process of photosynthesis takes places which creates the carbohydrates that the vine needs to grow and process grape clusters. The size of the leaves vary due to grape varieties with varieties like Merlot having very large leaves and Gewürztraminer noted for having small leaves. The typical size is normally comparable to that of a human hand. In addition to size, there are many of other unique characteristics to the leaves that ampelographers use for plant identification. The size and shape of the leaf's sinus (the opening space where the blade of the leaf connects to the petiole), the shape of the "teeth" along the outer edge, the arrangement of the five lobes or projecting parts and the angle and length of the veins can all assist in identifying the grapevine. [9]
The color of the leaf can be an indication of the health and nutrition of the vine. Chlorophyll in the leaf gives it a natural greenish color. Prior to the winter dormancy, the vine will stop being photosynthetically active which will contribute to a natural break down of chlorophyll and changing of color. However, deficiency in nitrogen or sulfur could cause the vine to turn prematurely (such as before harvest) yellow. The appearance of reddish spots of brown "dead zones" could be the sign of a viral infection (such as the leafroll virus) or contamination through the use of herbicides. [9]
Viticulturalist will use a leaf to fruit ratio as a guideline in determining a vine's ability to fully ripen grapes. Quite different from the consideration of yields, the balance of leaf cover (needed for photosynthesis) and proportion of fruit (judged by weight rather than number of clusters) could have the most substantial effect on the quality of the grape for winemaking. Pioneered by viticulturalist Richard Smart, the idea of maintaining a "balanced vine" is to have just enough leaf cover for the plant to produce the energy needed to ripen the grape without having too much photosynthetic activity to where the vines has a surplus of energy and continues growing more shoots. Additionally, leaves provide shade to the grape clusters which be beneficial in protecting the clusters from the harshness of heat stress ("sunburn") but excessive shade can also decrease the development of sugars, anthocyanins and other phenolics and other important compounds in the grape. Many vineyards employ the practice of leaf removal throughout the growing season to try to maintain optimal leaf coverage. [9]
Vitis vinifera, the common grape vine, is a species of flowering plant, native to the Mediterranean region, Central Europe, and southwestern Asia, from Morocco and Portugal north to southern Germany and east to northern Iran. As of 2012, there were between 5,000 and 10,000 varieties of Vitis vinifera grapes though only a few are of commercial significance for wine and table grape production.
Pinot Meunier, also known as Meunier or Schwarzriesling, is a variety of red wine grape most noted for being one of the three main varieties used in the production of Champagne. Until recently, producers in Champagne generally did not acknowledge Pinot Meunier, preferring to emphasise the use of the other noble varieties, but now Pinot Meunier is gaining recognition for the body and richness it contributes to Champagne. Pinot Meunier is approximately one-third of all the grapes planted in Champagne. It is a chimeric mutation of Pinot: its inner cell layers are composed of a Pinot genotype which is close to Pinot noir or Pinot gris; the outer, epidermal, layer is, however, made up of a mutant, distinctive, genotype. Pinot Meunier was first mentioned in the 16th century, and gets its name and synonyms from flour-like dusty white down on the underside of its leaves.
Viticulture, viniculture, or winegrowing is the cultivation and harvesting of grapes. It is a branch of the science of horticulture. While the native territory of Vitis vinifera, the common grape vine, ranges from Western Europe to the Persian shores of the Caspian Sea, the vine has demonstrated high levels of adaptability to new environments, hence viticulture can be found on every continent except Antarctica.
In botany, chlorosis is a condition in which leaves produce insufficient chlorophyll. As chlorophyll is responsible for the green color of leaves, chlorotic leaves are pale, yellow, or yellow-white. The affected plant has little or no ability to manufacture carbohydrates through photosynthesis and may die unless the cause of its chlorophyll insufficiency is treated and this may lead to a plant disease called rusts, although some chlorotic plants, such as the albino Arabidopsis thaliana mutant ppi2, are viable if supplied with exogenous sucrose.
Catawba is a red American grape variety used for wine as well as juice, jams and jellies. The grape can have a pronounced musky or "foxy" flavor. Grown predominantly on the East Coast of the United States, this purplish-red grape is a likely a hybrid of the native American Vitis labrusca and the Vitis vinifera cultivar Semillon. Its exact origins are unclear but it seems to have originated somewhere on the East coast from the Carolinas to Maryland.
Millerandage is a potential viticultural hazard in which grape bunches contain berries that differ greatly in size and, most importantly, maturity. Its most common cause is cold, rainy or otherwise bad weather during the flowering stage of the vines though other factors, such as boron deficiency or fanleaf degeneration, may also play a role.
Grolleau or Grolleau noir is a red French wine grape variety that is grown primarily in the Loire Valley of France. The name is derived from the French word grolle, meaning "crow" and is said to reflect the deep black berries of the Grolleau vine. The grape is most commonly made into rosé wine, particularly in the Anjou region. Grolleau wines tend to have low alcohol content and relatively high acidity.
Coulure is a viticultural hazard that is the result of metabolic reactions to weather conditions that causes a failure of grapes to develop after flowering. In English the word shatter is sometimes used. Coulure is triggered by periods of cold, cloudy, rainy weather or very high out-of-season temperatures. The condition is most often manifested in the spring. It also occurs in vines that have little sugar content in their tissue. Flowers stay closed and are not fertilized. Thus the vines are not pollinated as the grape fails to develop and falls off. Coulure can also cause irregular bunches of grapes which are less compact than normal. These bunches are more sensitive to developing various grape diseases. The yield of a vine with coulure will decrease substantially. Grape varieties with high proclivity to coulure are Grenache, Malbec, Merlot, and Muscat Ottonel. Other causes of coulure may be vineyard conditions and practices, pruning too early or too severely, excessively fertile soils or overuse of fertilizers, and improper selection of rootstocks or clones.
Vietnamese wine is wine produced in Vietnam. The area was first cultivated for viticulture during the French colonial rule of the region in the late 19th century. The region's tropical climate was ill-suited for the type of Vitis vinifera that the French colonists were used to and the wine industry turned its attention to fruit wine production. The late 20th century saw a renewed focus on the development of Vitis vinifera with the assistance of flying winemakers from regions like Australia. In 1995, a joint venture with Australian winemakers started an aggressive planting scheme to reintroduce international grape varieties like Cabernet Sauvignon and Chardonnay to land that was until recently littered with landmines left over from the Vietnam War.
Richard Smart is an Australian viticulturalist and leading global consultant on viticulture methods, who is often referred to as "the flying vine-doctor". He is considered responsible for revolutionising grape growing due to his work on canopy management techniques.
The annual growth cycle of grapevines is the process that takes place in the vineyard each year, beginning with bud break in the spring and culminating in leaf fall in autumn followed by winter dormancy. From a winemaking perspective, each step in the process plays a vital role in the development of grapes with ideal characteristics for making wine. Viticulturalists and vineyard managers monitor the effect of climate, vine disease and pests in facilitating or impeding the vine's progression from bud break, flowering, fruit set, veraison, harvesting, leaf fall and dormancy – reacting if need be with the use of viticultural practices like canopy management, irrigation, vine training and the use of agrochemicals. The stages of the annual growth cycle usually become observable within the first year of a vine's life. The amount of time spent at each stage of the growth cycle depends on a number of factors – most notably the type of climate and the characteristics of the grape variety.
The acids in wine are an important component in both winemaking and the finished product of wine. They are present in both grapes and wine, having direct influences on the color, balance and taste of the wine as well as the growth and vitality of yeast during fermentation and protecting the wine from bacteria. The measure of the amount of acidity in wine is known as the “titratable acidity” or “total acidity”, which refers to the test that yields the total of all acids present, while strength of acidity is measured according to pH, with most wines having a pH between 2.9 and 3.9. Generally, the lower the pH, the higher the acidity in the wine. There is no direct connection between total acidity and pH. In wine tasting, the term “acidity” refers to the fresh, tart and sour attributes of the wine which are evaluated in relation to how well the acidity balances out the sweetness and bitter components of the wine such as tannins. Three primary acids are found in wine grapes: tartaric, malic, and citric acids. During the course of winemaking and in the finished wines, acetic, butyric, lactic, and succinic acids can play significant roles. Most of the acids involved with wine are fixed acids with the notable exception of acetic acid, mostly found in vinegar, which is volatile and can contribute to the wine fault known as volatile acidity. Sometimes, additional acids, such as ascorbic, sorbic and sulfurous acids, are used in winemaking.
Precision viticulture is precision farming applied to optimize vineyard performance, in particular maximizing grape yield and quality while minimizing environmental impacts and risk. This is accomplished by measuring local variation in factors that influence grape yield and quality and applying appropriate viticulture management practices. Precision viticulture is based on the premise that high in-field variability for factors that affect vine growth and grape ripening warrants intensive management customized according to local conditions. Precision viticulture depends on new and emerging technologies such as global positioning systems (GPS), meteorologic and other environmental sensors, satellite and airborne remote sensing, and geographic information systems (GIS) to assess and respond to variability.
This glossary of viticultural terms list some of terms and definitions involved in growing grapes for use in winemaking.
In viticulture, ripeness is the completion of the ripening process of wine grapes on the vine which signals the beginning of harvest. What exactly constitutes ripeness will vary depending on what style of wine is being produced and what the winemaker and viticulturist personally believe constitutes ripeness. Once the grapes are harvested, the physical and chemical components of the grape which will influence a wine's quality are essentially set so determining the optimal moment of ripeness for harvest may be considered the most crucial decision in winemaking.
Irrigation in viticulture is the process of applying extra water in the cultivation of grapevines. It is considered both controversial and essential to wine production. In the physiology of the grapevine, the amount of available water affects photosynthesis and hence growth, as well as the development of grape berries. While climate and humidity play important roles, a typical grape vine needs 25-35 inches of water a year, occurring during the spring and summer months of the growing season, to avoid stress. A vine that does not receive the necessary amount of water will have its growth altered in a number of ways; some effects of water stress are considered desirable by wine grape growers.
The use of vine training systems in viticulture is aimed primarily to assist in canopy management with finding the balance in enough foliage to facilitate photosynthesis without excessive shading that could impede grape ripening or promote grape diseases. Additional benefits of utilizing particular training systems could be to control potential yields and to facilitate mechanization of certain vineyard tasks such as pruning, irrigation, applying pesticide or fertilizing sprays as well as harvesting the grapes.
Petit Bouschet is a red teinturier grape variety that is a crossing of Aramon noir and Teinturier du Cher created in 1824 by French grape breeder Louis Bouschet at his vineyard in Mauguio in the Hérault department. The grape was used by Louis' son, Henri Bouschet, to create several more varieties including Alicante Bouschet, Grand Noir de la Calmette and Morrastel Bouschet. Petit Bouschet saw a surge of plantings in the late 19th century as France recovered from the phylloxera epidemic where it was often used to add color to blends made from hybrid grapes and other high yielding varieties. As its offspring Alicante Bouschet became more popular, plantings of Petit Bouschet fell off and the grape is now hardly found in France.
The propagation of grapevines is an important consideration in commercial viticulture and winemaking. Grapevines, most of which belong to the Vitis vinifera family, produce one crop of fruit each growing season with a limited life span for individual vines. While some centenarian old vine examples of grape varieties exist, most grapevines are between the ages of 10 and 30 years. As vineyard owners seek to replant their vines, a number of techniques are available which may include planting a new cutting that has been selected by either clonal or mass (massal) selection. Vines can also be propagated by grafting a new plant vine upon existing rootstock or by layering one of the canes of an existing vine into the ground next to the vine and severing the connection when the new vine develops its own root system.
Versoaln is a white Italian wine grape variety that is grown in the South Tyrol wine region of northeast Italy. In the commune of Tisens, in South Tyrol, one of the world's oldest vines is a Versoaln vine planted at Katzenzungen Castle that has been dated to be at least 350 years old by the viticulturists at the University of Göttingen.