Banana

The bananas belong to the genus Musa but as the edible cultivars are sterile (seedless) hybrid forms, they cannot be given exact species names. They probably evolved in South-East Asia (India to New Guinea) in prehistoric times from wild species (Musa acuminata and Musa balbisiana are often quoted as the precursors of most banana cultivars), but have now spread throughout the tropics and subtropics. Banana plants are essentially of tropical humid lowlands. The plant is a tree-like herb (2-9 m tall). Its aerial 'stem' is actually composed of the overlapping bases of the leaves above and is known as a 'pseudostem'. The very large leaves often become torn by the wind. Its true stem is an underground 'corm' (about 30 cm long and wide) from which the leaves develop. Suckers also develop from the corm. They are used to propagate the plant. Alternatively, corm pieces bearing buds can be used.

Within a year after the sucker has been planted, the flowering stem will emerge at the apex of the plant and will gradually bend over to hang downwards. At its end this stem carries the sterile male flowers protected by large red bracts which are a conspicuous feature until they wither and fall away. Higher up the stem are borne the groups of female flowers which give rise to the seedless fruit without fertilization (parthenocarpy). Occasionally dark, hard seeds are formed in the fruit if pollen is received from nearby wild banana species. Banana fruits vary in length (6-35 cm) and color (green, yellow, or red). Although seeds are not actually formed, brown specks which represent the remains of ovules (ovules are structures which, after pollination and fertilization, give rise to seeds) may be seen. After fruiting the pseudostem is cut down but the plant is continued by suckers. In commercial cultivation, fields of bananas are most usually kept in existence for 5-20 years before replanting is undertaken, but many small farmers in the tropics maintain patches of bananas for 50-60 years.

Bananas are of enormous importance in terms of production, consumption, and trade. Roughly half the production is consumed fresh as dessert, the other half is cooked (fried, boiled, roasted, or baked). Sometimes green bananas presented for cooking are referred to as 'plantains' but it is not always possible to maintain the distinction. Dessert bananas only contain about 2 per cent starch but about 20 per cent total sugars (roughly half sucrose, the rest consisting of glucose and fructose). Vitamin C is present at 11 mg/100 g. In bananas for cooking the situation is reversed as regards the starch/sugar content, there being far more starch than sugar. Banana fruits have many other uses, such as being canned, made into purees, and included in bakery items and ice-creams. Thin slices of unripe fruit are made into chips (a snack food) and ripe fruits are sometimes dried (banana figs). Banana chips contain about 38 per cent starch and 22 per cent total sugars (mainly sucrose), but there is little vitamin C. In dried bananas there is about 50 per cent total sugars but the vitamin C content is much reduced. Dessert bananas are often considered a suitable and easily digestible food for babies and the elderly, also for those with intestinal complaints. In East Africa, beer is made from bananas. The male buds are eaten as a boiled vegetable in parts of South-East Asia. The chopped pseudostems and other plant parts are fed to cattle in East Africa.

In East Africa (Africa produces about 50 per cent of the world's bananas), cooking bananas are a staple food -consumption can be as much as 400 kg/person/year. The fruit is now an important item of international commerce, although this international trade only began somewhat over 100 years ago. Bananas for export to North America, Europe, and Japan are produced in Central and South America, the Caribbean, the Philippines, and Africa. Samoa and Fiji export to New Zealand. Production in Australia and South Africa is consumed locally.  Bananas for export are carried in the green condition in refrigerated ships. In the importing country they are ripened to the yellow state, sometimes with the help of ethylene gas.

A crop closely related to banana is 'ensete' (Ensete ventricosa), grown as a staple in some parts of southern and south-eastern Ethiopia at altitudes of 1500-3000 m. The pseudostems and corms are pulped. Either the pulp is cooked fresh or fermented and then made into bread.