Avocado Fruit

The Avocado (Persea americana) is a tree native to Mexico and Central America, classified in the flowering plant family Lauraceae. The name "avocado" is also applied to the fruit of the avocado tree. The tree grows to 20 metres (65 ft), with alternately arranged, evergreen leaves, 12-25 centimetres long. The flowers are inconspicuous, greenish-yellow, 5-10 millimetres wide. The pear-shaped fruit is botanically a berry, from 7 to 20 centimetres long, weighs between 100 and 1000 grams, and has a large central seed, 3 to 5 centimetres in diameter.

An average avocado tree produces about 120 avocados annually. Biennial bearing can be a problem, with heavy crops in one year being followed by poor yields the next. The fruit is sometimes called an avocado pear or alligator pear, due to its shape and rough green skin. The avocado tree does not tolerate freezing temperatures, and so can be grown only in subtropical and tropical climates.

The word "avocado" comes from the word aguacate, which derives from the Nahuatl (Aztec) word ahuacatl, meaning "testicle", because of its shape. In some countries of South America such as Argentina, Bolivia, Chile, Peru, and Uruguay, the avocado is known by its Quechua name, palta. In other Spanish-speaking countries it is called aguacate, and in Portuguese it is abacate. The name "avocado pear" is sometimes used in English, as are "alligator pear" and "butter pear". The Nahuatl ahuacatl can be compounded with other words, as in ahuacamolli, meaning "avocado soup or sauce", from which the word guacamole derives.

The subtropical species needs a climate without frost and not too much wind. When frost does occur, the fruit drops from the tree, reducing the yield, although the cultivar Hass can tolerate temperatures down to -1°C. The trees also need well aerated soils, ideally more than 1 m deep. Yield is reduced when the irrigation water is highly saline. These soil and climate conditions are met only in a few areas of the world, particularly in southern Spain, Israel, South Africa, Peru, northern Chile, Vietnam, Indonesia, Australia, New Zealand, the United States, the Philippines, Malaysia, Mexico and Central America, the center of origin and diversity of this species. In the U.S., avocados are primarily produced in California, Florida, and Hawaii. Each region has different types of cultivars.

While an avocado propagated by seed can bear fruit, it will take 4-6 years to do so, and the offspring is unlikely to resemble the parent cultivar in fruit quality. Thus, commercial orchards are planted using grafted trees and rootstocks. Rootstocks are propagated by seed (seedling rootstocks) and also layering (clonal rootstocks). After about a year of growing the young plants in a greenhouse, they are ready to be grafted. Terminal and lateral grafting is normally used.

The species is partially unable to self-pollinate, because of dichogamy in its flowering. The limitation, added to the long juvenile period, makes it difficult to breed this species. Most cultivars are clonally propagated (via grafting), having originated from random seedling plants or minor mutations derived from cultivars.

The avocado fruit does not ripen on the tree, but will fall off or be picked in a hard, "green" state. It will ripen quickly on the ground, but depending on the amount of oil that it has, the taste may be very different. Generally, the fruit is picked once it reaches a mature size, and will then ripen in a few days (faster if stored with other fruit such as bananas, because of the influence of ethylene gas). Premium supermarkets sell pre-softened avocados treated with synthetic ethylene to hasten the ripening process.[2] The fruit can be left on the tree until required, rather than picked and stored, but for commercial reasons it must be picked as soon as possible. Growers can keep the fruit on the tree for about 4-6 months after fully developed; if the fruit stays on the tree for too long it will fall to the ground.

The earliest known written account of the avocado in Europe is that of Martín Fernández de Enciso (c. 1470c. 1528) in 1519 in his book, Suma de Geografía que Trata de Todas las Partidas y Provincias del Mundo.

Persea americana, young avocado plant (seedling), complete with seed and rootsThe avocado was introduced to the U.S. state of California in the 19th century, and it has become an extremely successful cash crop.

Avocado can be grown as a houseplant from seed. It can be germinated in normal soil in a large pot or by suspending a washed pit (generally using toothpicks embedded in the sides) pointed-side up and filling the glass until the bottom quarter of the pit is covered. The pit will crack as it absorbs water and germinates, and should sprout within 4-6 weeks. When the roots and stem emerge from the seed, it can be planted in soil. The young tree is amenable to pruning and training but will not normally bear fruit indoors without sufficient sunlight or a second plant to cross-pollinate.

The fruit of horticultural cultivars ranges from more or less round to egg- or pear-shaped, typically the size of a temperate-zone pear or larger, on the outside bright green to green-brown (or almost black) in color. The fruit has a markedly higher fat content than most other fruits, mostly monounsaturated fat. A whole medium avocado contains approximately 15% of the United States FDA's recommended daily amount of saturated fat. Avocados also have 60% more potassium than bananas. They are also rich in B vitamins, as well as vitamin E, vitamin K, and folate. A ripe avocado will yield to a gentle pressure when held in the palm of the hand and squeezed. The flesh is typically greenish yellow to golden yellow when ripe. The flesh oxidizes and turns brown quickly after exposure to air. To prevent this, lime or lemon juice can be added to avocados after they are peeled. The avocado is very popular in vegetarian cuisine, making an excellent substitute for meats in sandwiches and salads because of its high fat content. The fruit is not sweet, but fatty, strongly flavored, and of smooth, almost creamy texture. It is used as the base for the Mexican dip known as guacamole, as well as a filling for several kinds of sushi, including California rolls. Avocado is popular in chicken dishes and as a spread on toast, served with salt and pepper. In Brazil, Vietnam, and Taiwan, avocados are frequently used for milk-shakes and occasionally added to ice cream. In the Philippines, Jamaica and Indonesia, a dessert drink is made with sugar, milk, and pureed avocado. In Central America, avocados are served mixed with white rice. The fruit is also pressed for avocado oil production. In Chile, it is often used in hamburgers, hot dogs and celery salads. Avocado flesh has also been used by some Native American tribes in the southwestern United States in the mixing and application of adobe, a natural building material.