The avocado is a fleshy exotic fruit obtained from the tropical tree of the same name. In some parts of South America it is known as Palta. It measures 5-6 cm in length. The normal weight ranges between 200-400 g, although there are some units that weigh up to 2 kg. The skin is thick and tough, of a green colour; the tone depends on the variety. The oily pulp of cream to greenish-yellow colour has a very similar taste to nuts. It has a single round seed of pale brown colour, 2-4 cm long.

Its content in oleic acid has beneficial cardiovascular effects, diminishing the levels of plasmatic cholesterol. It contains an important amount of minerals and vitamins, which are necessary for the correct functioning of the organism.

The avocado (Persea americana Mill.) is a fleshy exotic fruit obtained from the tropical tree of the same name. In some parts of South America it is known as Palta. It measures 5-6 cm in length. The normal weight ranges between 200-400 g, although there are some units that weigh up to 2 kg. The skin is thick and tough, of a green colour; the tone depends on the variety. The oily pulp of cream to greenish-yellow colour has a very similar taste to nuts. It has a single round seed of pale brown colour, 2-4 cm long, covered with a thin woody layer.

The fruit is a single-seeded, oval berry, of even or rough surface. Veraison only occurs in some varieties and the maturation of the fruit takes place when it is separated of the tree.

The pollination of this species is carried out by bees and other insects of similar size.

This fruit is characterized by a high percentage of fat. It is a very energetic fruit and it is not advisable to eat it after the meals. 100 g of this product provides with 128 to 233 kcal. It is extremely rich in minerals, chiefly potassium, iron and phosphorus. The avocado has a very low content of carbohydrates, not even 2 grams per 100g; for instance, an apple has 14 grams. However, it is known as the ‘vegetable butter" since it is very rich in fat, as indicated before. But this fat is a healthy, vegetal fat, unsaturated and free of cholesterol.

It is possible to eat it raw or cooked, although it is widely consumed as a vegetable more than as a fruit. It lacks a characteristic sweet or acid taste, thus enabling its combination with many dishes.

Avocados are sold all the year round. The colour of the skin depends on the variety and it is not an indicative of the degree of maturity of the fruit. The optimal moment for its consumption is determined by the softness of the pulp, when it can be spread like butter. Those which are still unripe are left 2 or 3 days at environmental temperature; the process of maturation stops if they are put in the fridge. However, we must take into account that this fruit does not withstand extremely low temperatures.

The harvesting procedure for its trade is carried out by determining the point of commercial maturation, that is the stage in which it is marketed and consumed. One of the signs used to determine the maturation point is the percentage of oil of the fruits. In California the minimum percentage of oil content must be 8% and 10% in Israel.

It is a subtropical species, quite demanding in regard to climatic conditions, reason why its culture is centred in areas with temperatures over the isotherm 16-17ºC. In Spain this area is placed in the coastal area between Málaga and Almería.

The main problem arising in the avocado’s trade is that once collected, its process of maturation is very fast, reason why it is necessary to choose post-harvest technologies that delay the climateric rise and/or the ethylene synthesis.

The avocados are trees of perennial leaf; the fruition takes place during the 4th or 7th year.

Most of the avocados are grouped in a single species: Persea americana Mill. The avocado is an extremely vigorous tree that may reach up to 30 ms high. Its root system is relatively superficial, lacking any visible radical hairs, but having in normal conditions multiple secondary rootlets. The wood of the stem is moderately hard and rough, not very resistant to intense wind.

The leaves are alternate, multiform (lanceolate to oval), with a length between 10 and 40 cm. The tree habit varies from an erect to an elongate low shape.

The small flowers are grouped in panicles that usually appear in terminal or sub-terminal position during the last vegetative growth. The flowering is usually at the end of winter-spring. The flowers have twelve stamina, a single pistil with only one carpel and one ovum. They have a calyx of three sepals and a three-petalled corolla.

All the avocados are grouped in two types, according to their floral behaviour, A and B. This floral behaviour only occurs in warm climate, particularly when day/night temperatures are of 25ºC/15ºC, respectively. The cultivars of group A have a better response when blooming in conditions of low temperatures than those of group B, that have also a suitable behaviour in these conditions.

Pollination is carried out by bees and other insects of similar size. The avocado fruit is a berry with a single seed. The fruit of many varieties are left in the tree and they continue growing and accumulating oil for several months after their suitable date of harvesting. The fruits have variable weights, 100 g up to 3 kg. They also vary in shape (from round to pear-shaped) and in colour (a range that goes from yellow- green to green, purple and black).

Concerning the suitable conditions for their development, daily temperatures must be around 15 and 20ºC. Temperatures over 36ºC cause serious damages, mainly in fertilization and fruit set.