Авокадо: Генеологиясы, өсірілуі және экологиялық ерекшеліктері

Species of flowering plant in the laurel family Lauraceae
the tree and fruit

The avocado, alligator pear or avocado pear (Persea americana) is a medium sized, evergreen tree in the laurel family (Lauraceae). It is native to the Americas and was first domesticated in Mesoamerica more than 5,000 years ago. Then as now it was prized for its large and unusually oily fruit. The tree likely originated in the highlands bridging south central Mexico and Guatemala. Its fruit, sometimes also referred to as an alligator pear or avocado pear, is botanically a large berry containing a single large seed. Sequencing of its genome showed that the evolution of avocados was shaped by polyploidy events and that commercial varieties have an hybrid origin. Avocado trees are partly self pollinating, and are often propagated through grafting to maintain consistent fruit output. Avocados are presently cultivated in the tropical and Mediterranean climates of many countries. In major production regions like Chile, Mexico and California the water demands of avocado farms place strain on local resources. Global warming is expected to result in significant changes to the suitable growing zones for avocados, and place additional pressures on the locales in which they are produced due to heat waves and drought.

Persea americana is a tree that grows to with a trunk diameter between The leaves are long and alternately arranged.

Panicles of flowers with deciduous bracts arise from new growth or the axils of leaves. The tree flowers thousands of blossoms every year. Avocado blossoms sprout from racemes near the leaf axils; they are small and inconspicuous wide. They have no petals but instead 2 whorls of 3 pale green or greenish yellow downy perianth lobes, each blossom has 9 stamens with 2 basal orange nectar glands. single seeded berry, due to the imperceptible endocarp covering the seed, rather than a drupe. The pear shaped fruit is usually long, weighs between , and has a large central seed, long.

Persea americana is regarded as an evolutionary anachronism, having likely coevolved dispersal of its large seed by now extinct megafauna in South America, notably giant ground sloths and the gomphothere genus of the elephant lineage. Following extinction of these original seed dispersers, humans migrating into the region are thought to have become primary long distance dispersers, eventuating in domestication of the species. In 1982, evolutionary biologist Daniel H. Janzen concluded that the avocado is an example of an "evolutionary anachronism", a fruit adapted for ecological relationship with now extinct large mammals (such as giant ground sloths or gomphotheres). Most large fleshy fruits serve the function of seed dispersal, accomplished by their consumption by large animals. There are some reasons to think that the fruit, with its mildly toxic pit, may have coevolved with Pleistocene megafauna to be swallowed whole and excreted in their dung, ready to sprout. The earliest known written account of the avocado in Europe is that of Martín Fernández de Enciso (c. 14701528) in 1519 in his book, Suma De Geographia Que Trata De Todas Las Partidas Y Provincias Del Mundo. The first detailed account that unequivocally describes the avocado was given by Gonzalo Fernández de Oviedo y Valdés in his work Sumario de la natural historia de las Indias in 1526. The first written record in English of the use of the word 'avocado' was by Hans Sloane, who coined the term, which goes back to the proto Aztecan pa:wa. In Molina's Nahuatl dictionary "auacatl" is given also as the translation for compañón "testicle", and this has been taken up in popular culture where a frequent claim is that testicle was the word's original meaning. This is not the case, as the original meaning can be reconstructed rather as "avocado" – rather the word seems to have been used in Nahuatl as a euphemism for "testicle". The modern English name comes from a rendering of the Spanish aguacate as avogato. The earliest known written use in English is attested from 1697 as avogato pear, later avocado pear (due to its shape), a term sometimes corrupted to alligator pear. it is known by the Mexican Spanish name aguacate, while South American Spanish speaking countries Argentina, Chile, Perú and Uruguay use a Quechua derived word, palta. In Portuguese, it is abacate. The Nahuatl āhuacatl can be compounded with other words, as in ahuacamolli, meaning avocado soup or sauce, from which the Spanish word guacamole derives. In the United Kingdom the term avocado pear, applied when avocados first became commonly available in the 1960s, is sometimes used. Originating as a diminutive in Australian English, a clipped form, avo, has since become a common colloquialism in South Africa and the United Kingdom. It is known as "butter fruit" in parts of India and Hong Kong.

Domestication, leading to genetically distinct cultivars, possibly originated in the Tehuacan Valley in the state of Puebla, Mexico. There is evidence for three possible separate domestications of the avocado, resulting in the currently recognized Guatemalan (quilaoacatl), Mexican (aoacatl) and West Indian (tlacacolaocatl) landraces. The Guatemalan and Mexican and landraces originated in the highlands of those countries, while the West Indian landrace is a lowland variety that ranges from Guatemala, Costa Rica, Colombia, Ecuador to Peru, The oldest discovery of an avocado pit comes from Coxcatlan Cave, dating from around 9,000 to 10,000 years ago. The plant was introduced to Spain in 1601, Indonesia around 1750, Mauritius in 1780, Brazil in 1809, the United States mainland in 1825, South Africa and Australia in the late 19th century, and the Ottoman Empire in 1908. According to information published by the Water Footprint Network, it takes an average of approximately of applied fresh ground or surface water, not including rainfall or natural moisture in the soil, to grow one avocado However, the amount of water needed depends on where it is grown; for example, in the main avocado growing region of Chile, about of applied water are needed to grow one avocado
Increasing demand and production of avocados may cause water shortages in some avocado production areas, such as the Mexican state of Michoacán. Avocados may also cause environmental and socioeconomic impacts in major production areas, illegal deforestation, and water disputes. Biennial bearing can be a problem, with heavy crops in one year being followed by poor yields the next. Like the banana, the avocado is a climacteric fruit, which matures on the tree, but ripens off the tree. Avocados used in commerce are picked hard and green and kept in coolers at until they reach their final destination. Avocados must be mature to ripen properly. Avocados that fall off the tree ripen on the ground. Generally, the fruit is picked once it reaches maturity; Mexican growers pick 'Hass' avocados when they have more than 23% dry matter, and other producing countries have similar standards. Once picked, avocados ripen in one to two weeks (depending on the cultivar) at room temperature (faster if stored with other fruits such as apples or bananas, because of the influence of ethylene gas). Some supermarkets sell ripened avocados which have been treated with synthetic ethylene to hasten ripening. The use of an ethylene gas "ripening room", which is now an industry standard, was pioneered in the 1980s by farmer Gil Henry of Escondido, California, in response to footage from a hidden supermarket camera which showed shoppers repeatedly squeezing hard, unripe avocados, putting them "back in the bin", and moving on without making a purchase. In some cases, avocados can be left on the tree for several months, which is an advantage to commercial growers who seek the greatest return for their crop, but if the fruit remains unpicked for too long, it falls to the ground.

Avocados can be propagated by seed, taking roughly four to six years to bear fruit, although in some cases seedlings can take 10 years to come into bearing. The offspring is unlikely to be identical to the parent cultivar in fruit quality. Prime quality varieties are therefore propagated by grafting to rootstocks that are propagated by seed (seedling rootstocks) or by layering (clonal rootstocks). After about a year of growing in a greenhouse, the young rootstocks are ready to be grafted. Terminal and lateral grafting is normally used. The scion cultivar grows for another 6–12 months before the tree is ready to be sold. Clonal rootstocks are selected for tolerance of specific soil and disease conditions, such as poor soil aeration or resistance to the soil borne disease (root rot) caused by Phytophthora cinnamomi. Advances in cloning techniques that can produce up to 500 new plants from a single millimetre of tree cutting have the potential to increase the availability of rootstocks. Commercial avocado production is limited to a small fraction of the vast genetic diversity in the species. Conservation of this genetic diversity has relied largely on field collection, as avocado seeds often do not survive storage in seed banks. This is problematic, as field preservation of living cultivars is expensive, and habitat loss threatens wild cultivars. More recently, an alternate method of conservation has been developed based on cryopreservation of avocado somatic embryos with reliable methods for somatic embryogenesis and reconstitution into living trees.

The avocado tree can be grown domestically and used as a decorative houseplant. The pit germinates in normal soil conditions or partially submerged in a small glass (or container) of water. In the latter method, the pit sprouts in four to six weeks, at which time it is planted in standard houseplant potting soil. The plant normally grows large enough to be prunable; it does not bear fruit unless it has ample sunlight. Home gardeners can graft a branch from a fruit bearing plant to speed maturity, which typically takes four to six years to bear fruit.

Avocado trees are vulnerable to bacterial, viral, fungal, and nutritional diseases (excesses and deficiencies of key minerals). Disease can affect all parts of the plant, causing spotting, rotting, cankers, pitting, and discoloration. The pyriform scale insect (Protopulvinaria pyriformis) is known from Australia, South Africa, Israel, Italy, France, Spain, Cuba, Florida, and Peru. It is normally found on avocado, and in Peru it is said to be the worst insect pest of the fruit. Certain cultivars of avocado seem more susceptible to attack by the scale than others.

Mexico is by far the world's largest avocado growing country, producing several times more than the second largest producer. In 2013, the total area dedicated to avocado production was , and the harvest was 2.03 million tonnes in 2017. It is such a problem that the phrase blood guacamole has been adopted to describe the social effects in Mexico of the vast worldwide demand for its fruits. with 60% in San Diego County. Avocado is the official fruit of the state of California. Fallbrook, California, claims, without official recognition, the title of "Avocado Capital of the World" (also claimed by the town of Uruapan in Mexico), and both it and Carpinteria, California, host annual avocado festivals. The California Avocado Commission and the California Avocado Society are the two major grower organizations and Calavo Growers is a major distributor.

'Hass' avocado production in Peru encompasses thousands of hectares in central and western Peru. Peru has now become the largest supplier of avocados imported to the European Union and the second largest supplier to Asia and the United States. The country's location near the equator and along the Pacific Ocean creates consistently mild temperatures all year. 'Hass' avocados from Peru are seasonally available to consumers from May through September and are promoted under the auspices of the Peruvian Avocado Commission, headquartered in Washington, D. C.

Chile has produced avocados for over 100 years with production increasing dramatically in the early 1980s due to global demand. New York magazine reported in 2015 that "Large avocado growers are draining the country's groundwater and rivers faster than they can replenish themselves."

'Choquette': A seedling from Miami, Florida. 'Choquette' bore large fruit of good eating quality in large quantities and had good disease resistance, and thus became a major cultivar. Today 'Choquette' is widely propagated in south Florida both for commercial growing and for home growing. 'Gwen': A seedling bred from 'Hass' x 'Thille' in 1982, 'Gwen' is higher yielding and more dwarfing than 'Hass' in California. The fruit has an oval shape, slightly smaller than 'Hass' , with a rich, nutty flavor. The skin texture is more finely pebbled than 'Hass', and is dull green when ripe. It is frost hardy down to 'Hass': The 'Hass' is the most common cultivar of avocado. It produces fruit year round and accounts for 80% of cultivated avocados in the world. All 'Hass' trees are descended from a single "mother tree" raised by a mail carrier named Rudolph Hass, of La Habra Heights, California. 'Lula': A seedling reportedly grown from a 'Taft' avocado planted in Miami on the property of George Cellon, it is named after Cellon's wife, Lula. It was likely a cross between Guatemalan and Mexican types. 'Lula' was recognized for its flavor and high oil content and propagated commercially in Florida. 'Maluma': A relatively new cultivar, it was discovered in South Africa in the early 1990s by Mr. A. G. (Dries) Joubert. It is a chance seedling of unknown parentage. 'Pinkerton': First grown on the Pinkerton Ranch in Saticoy, California, in the early 1970s, 'Pinkerton' is a seedling of 'Hass' x 'Rincon'. The large fruit has a small seed, and its green skin deepens in color as it ripens. The thick flesh has a smooth, creamy texture, pale green color, good flavor, and high oil content. It shows some cold tolerance, to and bears consistently heavy crops. A hybrid Guatemalan type, it has excellent peeling characteristics. 'Reed': Developed from a chance seedling found in 1948 by James S. Reed in California, this cultivar has large, round, green fruit with a smooth texture and dark, thick, glossy skin. Smooth and delicate, the flesh has a slightly nutty flavor. The skin ripens green. A Guatemalan type, it is hardy to Tree size is about .

'Fuerte': Commercialized in the U. S. from budwood imported from Atlixco, Mexico in 1911, Fuerte was the dominant commercial variety in the U. S. for the first half of the 20th century. 'Sharwil': Developed by James Cockburn Wilson (died 1990) with Frank Victor Sharpe in Tamborine Mountain, Queensland, Australia in the 1950s, a portmanteau of Sharpe and Wilson. Wilson also developed the Willard variety (Wilson and Hazzard), imported the Reed variety into Australia, and developed the Shepard variety. Sharpe was later awarded a CMG in 1972 for services to the avocado industry. The variety originated in Guatemala.

Other avocado cultivars include 'Spinks'. Historically attested varieties (which may or may not survive among horticulturists) include the 'Challenge', 'Dickinson', 'Kist', 'Queen', 'Rey', 'Royal', 'Sharpless', and 'Taft'.

A stoneless avocado, marketed as a "cocktail avocado", which does not contain a pit, is available on a limited basis. They are five to eight centimetres long; the whole fruit may be eaten, including the skin. It is produced from an unpollinated blossom in which the seed does not develop. Seedless avocados regularly appear on trees. Known in the avocado industry as "cukes", they are usually discarded commercially due to their small size.

Avocado production – 2020 Country Production (millions of tonnes) 2.39 0.88 0.68 0.66 0.61 0.32 World 8.06 Source: FAOSTAT of the United Nations

In 2020, world production of avocados was 8.1 million tonnes, led by Mexico with 30% (2.4 million tonnes) of the total (table). Other major producers were Colombia, Dominican Republic, Peru, and Indonesia, together producing 35% of the world total. In 2018, the US Department of Agriculture estimated that in total were under cultivation for avocado production in Mexico, a 6% increase over the previous year, and that 2 million tonnes would be exported. The Mexican state of Michoacán is the world leader in avocado production, accounting for 80% of all Mexican output. Most Mexican growers produce the Hass variety due to its longer shelf life for shipping and high demand among consumers. During 2020 in the United States, month to month volume sales of avocados were similar to those of tomatoes at about 250 million pounds (110 million kg) per month. is related to latex allergy and symptoms include generalised urticaria, abdominal pain, and vomiting and can sometimes be life threatening.

Avocado leaves, bark, skin, or pit are documented to be harmful to animals; cats, dogs, cattle, goats, rabbits, rats, guinea pigs, birds, fish, and horses can be severely harmed or even killed when they consume them. The avocado fruit is poisonous to some birds, and the American Society for the Prevention of Cruelty to Animals (ASPCA) lists it as toxic to horses. Avocado leaves contain a toxic fatty acid derivative, persin, which in sufficient quantity can cause colic in horses and without veterinary treatment, death. The symptoms include gastrointestinal irritation, vomiting, diarrhea, respiratory distress, congestion, fluid accumulation around the tissues of the heart, and even death. Birds also seem to be particularly sensitive to this toxic compound. The leaves of the Guatemalan variety of P. americana are toxic to goats, sheep, and horses.

Raw avocado flesh is 73% water, 15% fat, 9% carbohydrates, and 2% protein (table). In a 100 gram reference amount, avocado supplies , and is a rich source (20% or more of the Daily Value, DV) of several B vitamins (such as 28% DV in pantothenic acid) and vitamin K (20% DV), with moderate contents (10–19% DV) of vitamin C, vitamin E, and potassium. Avocados also contain phytosterols and carotenoids, such as lutein and zeaxanthin.

In addition to the fruit, the leaves of Mexican avocados (Persea americana var. drymifolia) are used in some cuisines as a spice, with a flavor somewhat reminiscent of anise. They are sold both dried and fresh, toasted before use, and either crumbled or used whole, commonly in bean dishes.