Millerandage

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A grape cluster with signs of millerandage with small, immature berries scattered throughout the bunch. Cluster with immature grapes.JPG
A grape cluster with signs of millerandage with small, immature berries scattered throughout the bunch.

Millerandage (or shot berries, hens and chicks and pumpkins and peas) is a potential viticultural hazard problem 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. [1]

Grape spherical berry from vines of Vitis spp.

A grape is a fruit, botanically a berry, of the deciduous woody vines of the flowering plant genus Vitis.

Boron Chemical element with atomic number 5

Boron is a chemical element with symbol B and atomic number 5. Produced entirely by cosmic ray spallation and supernovae and not by stellar nucleosynthesis, it is a low-abundance element in the Solar system and in the Earth's crust. Boron is concentrated on Earth by the water-solubility of its more common naturally occurring compounds, the borate minerals. These are mined industrially as evaporites, such as borax and kernite. The largest known boron deposits are in Turkey, the largest producer of boron minerals.

Contents

While millerandage will always cause a drop in yield, its potential impact on wine quality will vary, particularly by grape variety. For some varieties that are prone to uneven ripeness within a cluster, such as Sangiovese, Zinfandel and Gewürztraminer, the development of millerandage may be unfavorable due to "green flavors" from the potentially unripe grapes hidden within the cluster. For other varieties, such as Pinot noir or the Mendoza clone of Chardonnay, wine quality could be improved due to the reduced overall berry size and higher skin to juice ratio. [1]

Yield (wine) the amount of grapes or wine that is produced per unit surface of vineyard

In viticulture, the yield is a measure of the amount of grapes or wine that is produced per unit surface of vineyard, and is therefore a type of crop yield. Two different types of yield measures are commonly used, mass of grapes per vineyard surface, or volume of wine per vineyard surface.

Sangiovese wine making grape

Sangiovese is a red Italian wine grape variety that derives its name from the Latin sanguis Jovis, "the blood of Jupiter". Though it is the grape of most of central Italy from Romagna down to Lazio, Campania and Sicily, outside Italy it is most famous as the only component of Brunello di Montalcino and Rosso di Montalcino and the main component of the blends Chianti, Carmignano, Vino Nobile di Montepulciano and Morellino di Scansano, although it can also be used to make varietal wines such as Sangiovese di Romagna and the modern "Super Tuscan" wines like Tignanello.

Zinfandel plant with grapes used to make wine

Zinfandel is a variety of black-skinned wine grape. The variety is grown in over 10 percent of California vineyards. DNA analysis has revealed that it is genetically equivalent to the Croatian grapes Crljenak Kaštelanski and Tribidrag, as well as to the Primitivo variety traditionally grown in Apulia, where it was introduced in the 18th century. The grape found its way to the United States in the mid-19th century, where it became known by variations of a name applied to a different grape, likely "Zierfandler" from Austria.

Causes

During the flowering (inflorescence) stage, cool temperature and the presence of rain can influence the development of millerandage. Grape - inflorescence.jpg
During the flowering (inflorescence) stage, cool temperature and the presence of rain can influence the development of millerandage.

The root cause of millerandage is the poor fertilization of grape flowers during the growing season. While this is most often attributed to bad weather, other factors such as nutritional deficiencies (particularly of the mineral boron which is needed to synthesis the growth hormone auxin and facilitate the movement of sugars in the vine) or viral infections can play a role. [1]

Auxin class of plant hormones

Auxins are a class of plant hormones with some morphogen-like characteristics. Auxins have a cardinal role in coordination of many growth and behavioral processes in the plant's life cycle and are essential for plant body development. Auxins and their role in plant growth were first described by the Dutch biologist Frits Warmolt Went. Kenneth V. Thimann was the first to isolate one of these phytohormones and determine its chemical structure as indole-3-acetic acid (IAA). Went and Thimann co-authored a book on plant hormones, Phytohormones, in 1937.

Flowering and fruit set

For grapevines, flowering occurs usually 8 weeks after the beginning of bud break when the mean daily temperatures hit around 20 °C (68 °F). Usually flowering begins at the base of the inflorescence (cluster of flowers) and moves its way to the top. Following the apical dominance of grape vines, the uppermost shoots of the vine will begin flowering first with complete blooming taking place over 7 to 10 days. Ideally the temperature and weather condition for this period should be warm, sunny and dry to insure optimal flowering. For some varieties, such as Zinfandel and Merlot, flowering may be more staggered which poses a greater risk for inclemental weather disrupting the process and encouraging millerandage. Some growers may try to encourage more synchronized flowering with the use of chemical treatments, such as cyanamide. [2]

Inflorescence Term used in botany to describe a cluster of flowers

An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed. The modifications can involve the length and the nature of the internodes and the phyllotaxis, as well as variations in the proportions, compressions, swellings, adnations, connations and reduction of main and secondary axes. Inflorescence can also be defined as the reproductive portion of a plant that bears a cluster of flowers in a specific pattern.

Apical dominance

In botany, apical dominance is the phenomenon whereby the main, central stem of the plant is dominant over other side stems; on a branch the main stem of the branch is further dominant over its own side branchlets.

Merlot dark blue-colored variety of wine-making grape

Merlot is a dark blue-colored wine grape variety, that is used as both a blending grape and for varietal wines. The name Merlot is thought to be a diminutive of merle, the French name for the blackbird, probably a reference to the color of the grape. Its softness and "fleshiness", combined with its earlier ripening, makes Merlot a popular grape for blending with the sterner, later-ripening Cabernet Sauvignon, which tends to be higher in tannin.

Following flowering, the flowers of the grape vine go through pollination and fertilization over the next 2 to 3 days. Here is another opportunity where incremental weather can influence the outcome with temperature drops below 10 °C (50 °F) potentially damaging the ovules of the flowers before they can be fertilized. Since grapevines are hermaphroditic (containing both male and female parts) and usually rely on self-pollination, the presence of wind to circulate pollen or insects usually doesn't influence the success or failure of the pollination stage. [2] While not as influential as temperature, the presence of rain can "wash off" the pollen from the stigma or greatly dilute the stigmatic fluid, causing the pollen to absorb too much water, swelling and bursting before it reaches the ovules. [3]

Self-pollination when pollen from one flower pollinates the same flower or other flowers of the same individual

Self-pollination is when pollen from the same plant arrives at the stigma of a flower or at the ovule. There are two types of self-pollination: in autogamy, pollen is transferred to the stigma of the same flower; in geitonogamy, pollen is transferred from the anther of one flower to the stigma of another flower on the same flowering plant, or from microsporangium to ovule within a single (monoecious) gymnosperm. Some plants have mechanisms that ensure autogamy, such as flowers that do not open (cleistogamy), or stamens that move to come into contact with the stigma. The term selfing that is often used as a synonym, is not limited to self-pollination, but also applies to other types of self-fertilization.

Stigma (botany) part of a flower

The stigma is the receptive tip of a carpel, or of several fused carpels, in the gynoecium of a flower.

Grapes that develop millerandage will not have seeds, making them smaller and with potentially a higher juice to skin ratio which may be desirable in winemaking. However, these smaller berries may not fully ripen and could potentially add high acid and "green" flavors to the wine. Wine grape diagram en.svg
Grapes that develop millerandage will not have seeds, making them smaller and with potentially a higher juice to skin ratio which may be desirable in winemaking. However, these smaller berries may not fully ripen and could potentially add high acid and "green" flavors to the wine.

Even in the most ideal conditions, usually only 20-30% of flowers develop into mature fruit with fully developed seeds and auxin production. [2] If even fewer berries develop, the condition of coulure emerges while for developed berries, the number of seeds (or their absence) will influence the resulting size of the berries. Millerandge most often occurs when the partially fertilized grapes do not develop any seeds, leaving small (and potentially immature) berries present in a cluster of larger, otherwise mature berries. [1]

Coulure

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.

Influence on wine quality

While millerandage will always have an economic impact in reduced harvest yields, it may not always have a negative impact on the resulting quality of the wine. In some areas, such as the New World wine regions of Australia, California and New Zealand, the presence of millerandage in the a vineyard can be seen as a positive quality for a vintage due to the reduced average berry-size. [1] Some growers will even use chemical sprays to deliberately encourage millerandage. [4]

However, the small, seedless berries may never fully ripen and stay hard and green (with high acid) throughout the growing season. Some growers may choose to remove clusters with high preponderance of millerandge through green harvesting or choose to harvest the entirety of the crop later at higher ripeness levels to balance the high acid and potentially "green flavors" of the shot berries. Other growers will remove the grape post-harvest at a sorting table along with other MOG. [5]

Related Research Articles

Viticulture science, production and study of grapes

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. For this reason, viticulture can be found on every continent except Antarctica.

Durif Red wine grape

Durif is a variety of red wine grape primarily grown in Australia, California, France, and Israel. Since the end of the 20th century, wineries located in Washington's Yakima River Valley, Maryland, Arizona, West Virginia, Chile, Mexico's Baja California Peninsula, and Ontario's Niagara Peninsula have also produced wines from Durif grapes. It is the main grape known in the U.S. and Israel as Petite Sirah, with over 90% of the California plantings labeled "Petite Sirah" being Durif grapes; the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) recognizes "Durif" and "Petite Sirah" as synonyms for the same grape. It produces tannic wines with a spicy, plummy flavour. The grape originated as a cross of Syrah pollen germinating a Peloursin plant. On some occasions, Peloursin and Syrah vines may be called Petite Sirah, usually because the varieties are extremely difficult to distinguish in old age.

Mourvèdre wine grape

Mourvèdre is a red wine grape variety that is grown in many regions around the world including the Rhône and Provence regions of France, the Valencia and Jumilla denominaciones de origen of Spain, as well as the Balearic Islands, California and Washington State and the Australian regions of South Australia and New South Wales, as well as South Africa. In addition to making red varietal wines, Mourvèdre is a prominent component in "GSM" blends. The variety is also used to make rosé and port-style fortified wines.

Agiorgitiko varietal

Agiorgitiko is a red Greek wine grape variety that, as of 2012, was the most widely planted red grape variety in Greece, ahead of Xynomavro. The grape has traditionally been grown in the Nemea region of the Peloponnese but can be found throughout the country including Attikí (Attica) and Makedonía (Macedonia).

<i>Vitis labrusca</i> species of plant

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.

Plant breeders use different methods depending on the mode of reproduction of crops, which include:

<i>Vitis</i> genus of plants

Vitis (grapevines) is a genus of 79 accepted species of vining plants in the flowering plant family Vitaceae. The genus is made up 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.

Annual growth cycle of grapevines

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 vines 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.

Canopy (grape)

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. 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. 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.

This glossary of viticultural terms list some of terms and definitions involved in growing grapes for use in winemaking.

Ripeness in viticulture

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 may be considered the most crucial decision in winemaking.

Irrigation in viticulture

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.

Vine training

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.

Bianca (grape) varietal

Bianca is a white Hungarian wine grape variety that was developed in 1963 in the Eger wine region of northeast Hungary. The grape is a hybrid crossing of Bouvier and Eger 2. The grape was officially register for use in wine production in 1982 and today is used to make a wide assortment of wines from dry varietals to sweet dessert wines. Bianca is growing in popularity among organic vineyards due to its natural high resistance to many fungal diseases that affect grapevines.

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.

Œillade noire is a red French wine grape variety that has been historically grown in the Languedoc and Provence wine region but it is now close to extinction. The grape is often confused for the Rhone wine grape Cinsault which is known under the synonym œillade noire when it is sold as a table grape. It was also once thought to be a color mutation of Picardan which is known as œillade blanche and share several similar synonyms to œillade noire. However the grape has no known relation to both Cinsault and Picardan.

Cabernet blanc is a white German and Swiss wine grape variety that is a crossing of the French wine grape Cabernet Sauvignon and an unknown hybrid grape variety. The grape was bred by Swiss grape breeder Valentin Blattner in 1991. Cabernet blanc has strong resistance to most grape disease including botrytis bunch rot, downy and powdery mildew and tends to produce loose clusters of small, thick-skinned grape berries which can hang on the vine late into the harvest season to produce dessert wines. Today the grape is found primarily in the Palatinate wine region of Germany with some experimental plantings in the Netherlands.

Cygne blanc is a white Australian wine grape variety that is a seedling of Cabernet Sauvignon that was discovered in 1989 in Western Australia. Unlike Cabernet blanc, which was a crossing of Cabernet Sauvignon and Resistenzpartner, and Shalistin which is a white-berried color mutation of Cabernet Sauvignon, Cygne blanc is a selfling that sprang from a seed of a Cabernet Sauvignon berry that fell on the ground and took root.

Propagation of grapevines

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.

References

  1. 1 2 3 4 5 J. Robinson (ed) "The Oxford Companion to Wine" Third Edition pgs 77, 291, 322, 443 Oxford University Press 2006 ISBN   0-19-860990-6
  2. 1 2 3 R. Jackson "Wine Science: Principles and Applications" Third Edition pgs 70-72 Academic Press 2008 ISBN   978-0-12-373646-8
  3. Winkler AJ, Cook JA, Kliere WM and Lider LA General Viticulture 2nd Edition, pgw 126-133 University of California Press. 1974 ISBN   0-520-02591-1.
  4. T. Stevenson, ed. The Sotheby's Wine Encyclopedia (5th Edition) pg 23 Dorling Kindersley (2011) ISBN   978-0-7566-8684-0
  5. Clive Coates An Encyclopedia of the Wines and Domaines of France pgs 16 & 520 University of California Press; First Printing edition (June 2001) ISBN   0-520-22093-5