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. [1]
The word chlorosis is derived from the Greek khloros meaning "greenish-yellow", "pale green", "pale", "pallid", or "fresh".
In viticulture, the most common symptom of poor nutrition in grapevines is the yellowing of grape leaves caused by chlorosis and the subsequent loss of chlorophyll. This is often seen in vineyard soils that are high in limestone such as the Italian wine region of Barolo in the Piedmont, the Spanish wine region of Rioja and the French wine regions of Champagne and Burgundy. In these soils the grapevine often struggles to pull sufficient levels of iron which is a needed component in the production of chlorophyll. [2]
Chlorosis is typically caused when leaves do not have enough nutrients to synthesise all the chlorophyll they need. It can be brought about by a combination of factors including:
However, the exact conditions vary from plant type to plant type. For example, Azaleas grow best in acidic soil and rice is unharmed by waterlogged soil.
Like many other plants, grape vines are susceptible to chlorosis, and symptoms of iron deficiency tend to be common on soils rich in limestone. In the wake of The Great French Wine Blight, when European Vitis vinifera were affected by Phylloxera , chlorosis became a greater problem in viticulture. To deal with the Phylloxera blight, V. vinifera was grafted onto rootstock based on American species of the genus Vitis , such as Vitis riparia , Vitis rupestris , and Vitis berlandieri . However, many of these were less adapted to the lime-rich soils that were common in France's vineyards, in particular many of those that produced wines of top quality. Many grafted vines in lime-rich vineyards therefore showed signs of iron deficiency, and in France this specific form of chlorosis was termed chlorose calcaire. The problem was largely overcome by the selection of lime-resistant American vines as basis for hybrid vines used for rootstock material. However, since such rootstocks may be less than optimal in other respects, it is necessary for the viticulturalist to balance the need for chlorosis resistance against other viticultural needs. This is illustrated by one of the most common lime-resistant rootstocks, 41 B, which is a hybrid between V. vinifera cultivar Chasselas and V. berlandieri, which generally has a sufficient, but not extremely high, Phylloxera resistance. [9] [10]
Specific nutrient deficiencies (often aggravated by high soil pH) may be corrected by supplemental feedings of iron, in the form of a chelate or sulphate, magnesium or nitrogen compounds in various combinations. If the soil is too acidic, applying lime can raise the pH to the proper range, making more nutrients available to the plant. Likewise, sulfur can be used to lower soil pH if it is too alkaline. [11]
A vineyard is a plantation of grape-bearing vines, grown mainly for winemaking, but also raisins, table grapes, and non-alcoholic grape juice. The science, practice and study of vineyard production is known as viticulture. Vineyards are often characterised by their terroir, a French term loosely translating as "a sense of place" that refers to the specific geographical and geological characteristics of grapevine plantations, which may be imparted to the wine itself.
Grape phylloxera is an insect pest of grapevines worldwide, originally native to eastern North America. Grape phylloxera ; originally described in France as Phylloxera vastatrix; equated to the previously described Daktulosphaera vitifoliae, Phylloxera vitifoliae. The insect is commonly just called phylloxera.
Viticulture 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.
Vitis labrusca, the fox grape, is a species of grapevines belonging to the Vitis genus in the flowering plant family Vitaceae. The vines are native to eastern North America and are the source of many grape cultivars, including Catawba, Concord, Delaware, Isabella, Niagara, and many hybrid grape varieties such as Agawam, Alexander and Onaka. Among the characteristics of this vine species in contrast to the European wine grape Vitis vinifera are its "slip-skin" that allows the skin of the grape berries to easily slip off when squeezed, instead of crushing the pulp, and the presence of tendrils on every node of the cane. Another contrast with European vinifera is the characteristic "foxy" musk of V. labrusca, best known to most people through the Concord grape. This musk is not related to the mammalian fox, but rather to the strong, earthy aromas characteristic of the grapes that were known by early European-American settlers in the New World. The term "foxy" became a sort of catchall for the wine tasting descriptors used for these American wines that were distinct from the familiar flavors of the European viniferous wines.
Vitis riparia Michx, with common names riverbank grape or frost grape, is a vine indigenous to North America. As a climbing or trailing vine, it is widely distributed across central and eastern Canada and the central and northeastern parts of the United States, from Quebec to Texas, and eastern Montana to Nova Scotia. There are reports of isolated populations in the northwestern USA, but these are probably naturalized. It is long-lived and capable of reaching into the upper canopy of the tallest trees. It produces dark fruit that are appealing to both birds and people, and has been used extensively in commercial viticulture as grafted rootstock and in hybrid grape breeding programs.
A rootstock is part of a plant, often an underground part, from which new above-ground growth can be produced. It could also be described as a stem with a well developed root system, to which a bud from another plant is grafted. It can refer to a rhizome or underground stem. In grafting, it refers to a plant, sometimes just a stump, which already has an established, healthy root system, onto which a cutting or a bud from another plant is grafted. In some cases, such as vines of grapes and other berries, cuttings may be used for rootstocks, the roots being established in nursery conditions before planting them out. The plant part grafted onto the rootstock is usually called the scion. The scion is the plant that has the properties that propagator desires above ground, including the photosynthetic activity and the fruit or decorative properties. The rootstock is selected for its interaction with the soil, providing the roots and the stem to support the new plant, obtaining the necessary soil water and minerals, and resisting the relevant pests and diseases. After a few weeks, the tissues of the two parts will have grown together, eventually forming a single plant. After some years, it may be difficult to detect the site of the graft although the product always contains the components of two genetically different plants.
Thomas Volney Munson, often referred to simply as T.V. Munson, was a horticulturist and breeder of grapes in Texas. In 1888, Munson was the second American, after Thomas Edison, to be named a Chevalier du Mérite Agricole by the French government.
Washington wine is a wine produced from grape varieties grown in the U.S. state of Washington. Washington ranks second in the United States in the production of wine. By 2017, the state had over 55,000 acres (220 km2) of vineyards, a harvest of 229,000 short tons (208,000 t) of grapes, and exports going to over 40 countries around the world from the 940+ wineries located in the state. While there are some viticultural activities in the cooler, wetter western half of the state, the majority (99.9%) of wine grape production takes place in the shrub-steppe eastern half. The rain shadow of the Cascade Range leaves the Columbia River Basin with around 8 inches (200 mm) of annual rain fall, making irrigation and water rights of paramount interest to the Washington wine industry. Viticulture in the state is also influenced by long sunlight hours and consistent temperatures.
Canaiolo is a red Italian wine grape grown through Central Italy but is most noted in Tuscany. Other regions with plantings of Canaiolo include Lazio, Marche and Sardegna. In Umbria a white berried mutation known as Canaiolo bianco exists. Together with Sangiovese and Colorino it is often used to create Chianti wine and is an important but secondary component of Vino Nobile di Montepulciano. In the history of Chianti it has been a key component blend and during the 18th century may have been the primarily grape used in higher percentage than Sangiovese. Part of its popularity may have been the grape's ability to partially dry out without rotting for use in the governo method of prolonging fermentation. In the 19th century, the Chianti recipe of Bettino Ricasoli called for Canaiolo to play a supporting role to Sangiovese, adding fruitiness and softening tannins without detracting from the wine's aromas. In the aftermath of the phylloxera epidemic, the Canaiolo vines did not take well to grafting onto new American rootstock and the grape began to steadily fall out of favor. As of 2006, total plantings of Canaiolo throughout Italy dropped to under 7,410 acres. Today there are renewed efforts by Tuscan winemakers to find better clonal selections and re-introduce the variety into popular usage.
Gros Verdot is a red French wine grape variety that was a historically important grape in the Gironde wine region of Bordeaux but plantings of the variety have been banned in the region since 1946 with the grape no longer being a permitted variety in any AOC Bordeaux wines.
Bouchalès or Grapput is a red French wine grape variety that is grown primarily in Bordeaux and Southwest France wine appellations. Plantings have declined in recent years as the vine has shown high sensitivity to downy mildew and black rot.
Aramon or Aramon noir is a variety of red wine grape grown primarily in Languedoc-Roussillon in southern France. Between the late 19th century and the 1960s, it was France's most grown grape variety, but plantings of Aramon have been in continuous decline since the mid-20th century. Aramon has also been grown in Algeria, Argentina and Chile but nowhere else did it ever reach the popularity it used to have in the south of France.
Couderc noir is a red wine hybrid grape that was formerly grown primarily in the South West France wine region and around the Gard département in the Languedoc-Roussillon region. The vine produces high yields and ripens late, creating a wine that is deeply colored with a distinct, earthy flavor. Couderc noir is normally used for mass commercial and table wines.
Vitis (grapevine) is a genus of 81 accepted species of vining plants in the flowering plant family Vitaceae. The genus consists of species predominantly from the Northern Hemisphere. It is economically important as the source of grapes, both for direct consumption of the fruit and for fermentation to produce wine. The study and cultivation of grapevines is called viticulture.
The Great French Wine Blight was a severe blight of the mid-19th century that destroyed many of the vineyards in France and laid waste to the wine industry. It was caused by an aphid that originated in North America and was carried across the Atlantic in the late 1850s. The actual genus of the aphid is still debated, although it is largely considered to have been a species of Daktulosphaira vitifoliae, commonly known as grape phylloxera. While France is considered to have been worst affected, the blight also did a great deal of damage to vineyards in other European countries.
Vitis berlandieri is a species of grape native to the southern North America, primarily Texas, New Mexico and Arkansas.
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.
This glossary of viticultural terms list some of terms and definitions involved in growing grapes for use in winemaking.
Cascade is a red complex hybrid grape variety that was created by French viticulturist Albert Seibel in the early 20th century in Aubenas, Ardèche, in the Rhône Valley. It has been commercially available in North America since 1938 and has since been planted in Canada and the United States. However, in warmer climates the grape is highly susceptible to a number of grapevine viruses, which has discouraged plantings of the variety.
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.