Banana (Musa spp.) is one of the most important tropical fruits. Ripe banana fruits are sugary and eaten raw; unripe fruits, called plantains, are cooked and provide a starchy food with nutritional value similar to potato. Total world production of banana is about 68.6 million tons of fresh fruit (FAOSTAT, 2001).
The cultivated banana is believed to have originated in the lowland, humid tropics in Southeast Asia and is mostly grown between 30°N and S of the equator. A mean temperature of about 27°C is optimal for growth. Minimum temperature for adequate growth is about 16°C, below which growth is checked and shooting delayed. Temperatures below 8°C for long periods cause serious damage. Maximum temperature for adequate growth is about 38°C, depending on humidity and the radiation intensity. Bananas are day-neutral in their response to daylength.
A humidity of at least 60 percent or more is preferable. Strong winds, greater than 4 m/sec, area major cause of crop loss due to the pseudostems being blown down. Under high wind conditions windbreaks are desirable.
Bananas can be grown on a wide range of soils provided they are fertile and well-drained. Stagnant water will cause diseases such as the Panama disease. The best soils are deep, well-drained loams with a high water holding capacity and humus content. Optimum pH is between 5 and 7. The demands for nitrogen and especially potash are high. Since the early stages of growth are critical for later development, nutrients must be ample at the time of planting and at the start of a ratoon crop. Short intervals between fertilizer applications, especially nitrogen, are recommended. Fertilizer requirements are 200 to 400 kg/ha N, 45 to 60 kg/ha P and 240 to 480 kg/ha K per year.
Banana is very sensitive to salinity and soils with an ECe of less than 1 mmho/ cm are required for good growth.
Banana, 2 to 9m tall, bears leaves on a pseudostem consisting of leaf stalks. The flowering stalk emerges (shooting) from the pseudostem and produces a hanging bunch of flowers. Fruits are formed on 'hands' with about 12 fingers; each bunch contains up to 150 fingers. After harvest the pseudostem is cut. The underground stem (corm or rhizome) bears several buds which, after sprouting, form new pseudostems, or so-called suckers. They are removed except for one or two which provide the ratoon crop.
Banana is normally multiplied vegetatively. Several types of suckers can be used. The development of the plant can be divided into three periods: vegetative, flowering and yield formation. The time from planting to shooting (vegetative) is about 7 to 9 months, but with lower temperatures at higher altitudes or in the subtropics, up to 18 months. The time from shooting to harvest (flowering and yield formation) is about 90 days. In tropical lowlands the time to harvest of the next ratoon crop is about 6 months. The number of ratoons varies. The average life of a commercial plantation can be from 3 to 20 years; with mechanical cultivation the economic life is often 4 to 6 years. Some varieties are replanted after each harvest.
Planting distances vary according to variety, climate, soil and management and are between 2 x 2 m and 5 x 5 m, corresponding to a density of 400 to 2500 plants/ha. On steep slopes contour planting is practised. The crop is sometimes interplanted or is used as a nurse crop for crops such as cocoa.
Following figure presents the development of banana (Champion, 1963)