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| Bananas and plantains |
Bananas and plantains (
Musa) have
played interesting and important roles in the history of human
civilizations. These seedless fruits are eaten and joked about by
Westerners, but they also constitute a crucial part of human diets in
all tropical regions. In the same plot of land where one could harvest
98 pounds of white potatoes or 33 pounds of wheat, a person could also
harvest 4400 pounds of bananas with very little labor.
Banana and plantain are perennial crops that take the appearance of
trees as they mature. Diverse cultivars are grown. The word “banana” are
believed to have originated in coastal West Africa, presumably in
Guinea or Sierra Leone, and was adopted in the New World for the sweet
forms with yellow skin (peel). The word plantain is now widely used to
refer to the starchy cooking bananas, which often have green or red
skins. Plantain presumably originated from the Spanish word “plantano”.
The sweet banana is easily digested, but plantain must be boiled, steamed, roasted, or deep fried to make it soft and palatable.
Throughout history
Musa has provided humans with food,
medicine, clothing, tools, shelter, furniture, paper, and handicrafts.
It could be termed the “first fruit crop” as its cultivation originated
during a time when hunting and gathering was still the principal means
of acquiring food.
Musa are rich in vitamin C, B6, minerals and dietary fibre.
They are also a rich energy source, with carbohydrates accounting for
22% and 32% of fruit weight for banana and plantain, respectively.
Around the world, there are more than 100 common names used for the fruits of Musa.
Banana (
Musa acuminate)
Bananas are cultivated in nearly all tropical regions of the world.
Of particular importance to Africa is the East African Highland Banana
(EAHB) which is a staple starchy food for 80 million people and
important source of income. There are 120 EAHB varieties in Uganda alone
that are not found anywhere else in the world. Banana is a monoecious
plant. Its inflorescence has male flowers at the tip, several sterile
flowers, and female flowers behind.
For wild bananas, birds usually pollinate the female flowers, but
pollination is unnecessary for fruit set of the cultivated forms, which
form sterile fruits automatically without the presence of pollen. This
type of fruit development is called parthenocarpy.
The ovules that were present in the ovary abort their development,
and the pulp subsequently is produced by the enlargement of the internal
tissues of the ovary, particularly from the inner face of the skin and
the enlargement of the septa and central axis. These cell divisions are
stimulated by the presence of high levels of auxin in those tissues,
which are not present if the ovules are fertilized. Wild bananas have
fairly dry fruits with large seeds and no pulp.
Plantain (Musa paradisiaca)
Plantain resemble banana but are longer in length, have a thicker
skin, and contain more starch. They are also a major staple food in
Africa, Latin America, and Asia. They are usually cooked green, either
boiled or fried, and not eaten raw unless they are very ripe. It may
also be dried for later use in cooking or ground for use as a meal. The
plantain meal can be further refined to a flour.
Plantains are more important in the humid lowlands of West and
Central Africa. One hundred or more different varieties of plantain grow
deep in the African rainforests.
It is a tall plant (3–10 metres [10–33 feet]) with a conical false
“trunk” formed by the leaf sheaths of its spirally arranged leaves,
which are 1.5 to 3 m long and about 0.5 m wide. The fruit, which is
green, is typically larger than the common banana.
The botanical classification of plantains and bananas is so
complicated that plantain is variously viewed as a subspecies of banana,
and banana as a subspecies of plantain.
Importance
Banana and plantain are important staple foods in many developing
countries, especially in Africa. Of the numerous edible varieties, the
EAHB accounts for 17% of the types of Musa grown worldwide, and plantain
accounts for another 19%.
They provide food security and income for small-scale farmers who
represent the majority of producers. Only about 15% of the global banana
and plantain production is involved in international trade; most
production is consumed domestically.
Banana starch, flour, and chips are processed banana products whose markets are yet to be fully developed.
Production
More than 100 million tons of banana and plantain were produced
worldwide in 2007 according to Food and Agriculture Organization, FAO
estimates. Bananas are grown in nearly 130 countries. Uganda is the
largest producer of banana and plantain in sub-Saharan Africa (SSA),
followed by Rwanda, Ghana, Nigeria, and Cameroon.
Banana and plantain are cultivated in a wide variety of environments.
These Plants produce fruit year round and can produce for up to one
hundred years and are suitable for intercropping. Vegetative propagation
is necessary because they rarely produce seeds and those are not true
to variety.
Harvesting
In 2007 more than 9.9 million hectares of banana and plantain were
harvested worldwide and marketed across longer distances. Post-harvest
plantain losses are heavy due to poor handling and transport conditions
and inadequate market access routes.
Consumption
Africans annually consume 21 kg of banana and plantain per capita,
but Ugandans consume 191 kg per year, or more than half of one kg per
day. In fact, Ugandans use the same word for food as the name of the
local banana dish matooke. Four African countries have the highest per
capita consumption of banana/plantain in the world, with Uganda having
the highest.
Pest and disease incidence
Black Sigatoka disease is considered the most economically important
disease of banana worldwide, causing typical yield losses up to 50%. The
fungus grows on the leaves producing dark spots and causes the fruits
to ripen prematurely.
Banana Xanthomonas Wilt (BXW) attacks almost all varieties of Musa,
destroying the fruits and devastating the crop. It was first identified
in Ethiopia in the 1970s, but spread rapidly to other parts of the Great
Lakes region after reaching Uganda in 2001. Fusarium wilt has had a
huge impact on the world banana trade and is found in every
banana/plantain producing area. It is spread through corms used for
planting.
The major banana and plantain pests are the burrowing nematode and
the banana weevil. Nematode species attack the plant’s roots, resulting
in whole plant toppling or reduced yield. The banana weevil,
Cosmopolites sordidus, attacks the plant’s underground corm, weakening
the plant and causing stem breakage.
Meanwhile, the International Institute of Tropical Agriculture, IITA
scientists have developed and introduced high yielding, disease and pest
resistant varieties with durable fruit quality. Various institutions
have adopted IITA’s different Musa breeding schemes.
IITA has also developed and is promoting hot water treatment to rid
plants of nematodes and to produce clean planting materials. Another
important control tactic is the use of nematode-antagonistic plants that
inhibit nematode reproduction.
To combat BXW, IITA is collaborating with partners internationally to
develop reliable and cost effective diagnostic tools. Also, a genetic
transformation system developed and optimized at IITA can be used to
produce BXW-resistant varieties of banana.
IITA has successfully identified variations within the Black Sigatoka
species in Africa and the possibility to design new diagnostic tools.
Such tools would enhance the capacity of subsequent projects in selected
countries in SSA.
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