Cocoyam's (Colocasia and Xanthosoma spp.) are stem
tubers that are widely cultivated in both the tropical
and subtropical regions of the world.
the two species mostly grown in West Africa are
Colocasia esculenta and Xanthosoma sagittifolium
Cocoyam's can be processed into several industrial
inputs, food and feed products, similar to products
from potatoes in the Western world.
The processing of the crops include
boiling, roasting, frying in oil, pasting, milling and
conversion into ‘fufu’, soup thickeners, flour for
baking, chips, beverage powder, porridge, and special
food for gastro-intestinal disorders
Cocoyam leaves are used in many homes as a leafy
vegetable (pot herb) and can also be fed to poultry as
It is also reported to be one of the most promising
forages because of its re-growth capacity, high yield
leaves could be fed to growing pigs, while the petioles
are considered to be more appropriate for feeding to
pregnant sows, which need lower levels of protein in
the diet and are able to tolerate bulky feeds as well
The Neat Food Company, uses cocoyam to make fufu
Akwaba Food Company which exports chopped
cocoyam leaves and chips to Europe
The young leaves and petioles which are occasionally
used for food contain about 23% protein on a dry
They are also rich a source of
calcium, phosphorus, iron, Vitamin
C, thiamine, riboflavin and niacin, all of which are
important constituents of the human
In Ghana the crop is grown on a small scale and
usually as an intercrop together with
cocoa, plantains, oil palm and cassava.
Evidence exists that although cocoyam is cultivated on
a small scale, it has been able to contribute
significantly to the national food baskets. They also
serve as a source of income for many families
Xanthosoma Sagittifolium is a tropical rain forest plant and
requires an annual rainfall of about 1800mm per annum.
It prefers a well drained soil with pH 5.5 – 6.5
(Owueme, 1991). Although in their natural habitat they
grow under the forest canopy
they can be cultivated in areas with full exposure to
sunlight (Owueme, 1991).
Most tuber crops including cocoyam grow and yield well in
soils that are ploughed to a depth of about 20-40cm
especially on clay soils.
Cultivation of the crop
The major planting material for cocoyam is the main
stem (corm), although cormels can also be used.
Selected corms are cut into pieces of about 100 to 200
grams with each piece having at least a bud
For rapid field multiplication, fresh, healthy cocoyam
corms and cormels are cut into pieces of about 5 to 10
treated with (fungicide) and
nursed in black polybags containing steam-sterilized
2:1 top soil: sand potting mixture
Plantlets developed by the rapid field technique are
kept under shade for about three months before they
are planted out in their permanent fields.
Planting materials raised from microsetts during the
dry season and planted at the onset of the rains yield
about twice more than plants grown from 100-200g cut
corms at the beginning of the rainy season
When cocoyam's are grown in high moisture
regimes, fertilizers applied to them are subjected to
leaching and should therefore be applied in split
The first application is done at planting whiles the
second application is done three or four months after
planting (Owueme and Sinha, 1991).
Most farmers in tropical Africa cultivate cocoyam
without applying any chemical fertilizers.
They rely mostly on the native fertility of the
soil, which is very high when virgin forest is used to
They may sometimes place compost or farmyard
manure in the planting holes before planting
HARVESTING AND STORAGE
Cocoyam is ready for harvesting after 9-11 months
after planting. Maturity indicator for cocoyam is
yellowing of the leaves.
For. X saggitifolium, multiple harvesting is done thus
only the cormels are removed at each harvest while the
corm is left to produce new generations of
cormels, which will be harvested latter.
Harvesting is usually by hand or hand tools.
Alternatively the crop may be ploughed out after
which the corm and cormels are picked manually.
HARVESTING AND STORAGE
Cocoyam can be stored for up to four months when kept
under 7oC at a relative humidity of 85% (Owueme and
Storage under high temperatures increases
respiration, rotting and sprouting, shortening storage life
Too low temperatures also cause corm decay (Owueme and
Traditional storage methods include storage in
underground pits or on open platforms. Some farmers also
leave the crop in the field and harvest it as needed
The following varieties are recommended for their high
yield and processing quality:
TMS 4(2) 1425,
TMS 92/0326. ECT
suitable for fufu, gari and cassava dough and starch
Esam Bankye also good gari, agblema and starch.
Cassava is a tropical root crop, requiring at least 8
months of warm weather to produce a crop.
It is traditionally grown in a savanna climate, but can
be grown in extremes of rainfall.
In moist areas it does not tolerate flooding. In
droughty areas it looses its leaves to conserve
moisture, producing new leaves when rains resume
.It takes 18 or more months to produce a crop under
adverse conditions such as cool or dry weather.
Cassava does not tolerate freezing conditions.
It tolerates a wide range of soil pH 4.0 to 8.0 and is
most productive in full sun.
Cassava is planted using 7-30 cm portions of the
mature stem as propagules.
The selection of healthy, disease-free and pest-free
propagules is essential.
The stem cuttings are sometimes referred to as 'stakes'.
In areas where freezing temperatures are possible.
The cuttings are planted by hand in moist, prepared
soil, burying the lower half.
When soils are too shallow to plant the cutting in an upright or
the cutting are laid flat and covered with 2-3 cm soil
Mechanical planters have been developed in Brazil to reduce
Typical plant spacing is 1m by 1m. Cuttings produce roots within
a few days and new shoots soon appear at old leaf petiole axes on
Botanical seeds are used only for breeding purposes.
Early growth is relatively slow, thus weeds must be
controlled during the first few months.
Although cassava can produce a crop with minimal
inputs, optimal yields are recorded from fields with
average soil fertility levels for food crop production
and regular moisture availability.
Responses to macro-nutrients vary, with cassava
responding most to P and K fertilization.
High N fertilization, more than 100 kg of actual N/ha
may result in excessive foliage production at the
expense of storage root development and a low harvest
Fertilizer is only applied during the first few months of
Plants are ready for harvest as soon as there are storage
roots large enough to meet the requirements of the
consumer. Under the most favorable conditions, yields
of fresh roots can reach 90 t/ha while average world
yields from mostly subsistence agricultural systems are
Typically harvesting can begin as soon as eight months
In the tropics, plants can remain unharvested for more
than one growing season, allowing the storage roots to
However, as the roots age, the central portion
becomes woody and inedible
Most cassava is harvested by hand, lifting the lower part of
stem and pulling the roots out of the ground, then
removing them from the base of the plant by hand.
The upper parts of the stems with the leaves are removed
Levers and ropes can be used to assist harvesting. A
mechanical harvester has been developed in Brazil. It
grabs onto the stem and lifts the roots from the
Care must be taken during the harvesting process to
minimize damage to the roots, as this greatly reduces
During the harvesting process, the cuttings for the
next crop are selected. These must be kept in a
protected location to prevent desiccation.
Cassava is famous for the presence of free and bound
cyanogenic glucosides, linamarin and lotaustralin.
They are converted to HCN in the presence of
linamarase, a naturally occurring enzyme in cassava.
Linamarase acts on the glucosides when the cells are
ruptured. All plant parts contain cyanogenic
glucosides with the leaves having the highest
In the roots, the peel has a higher concentration than
the interior. In the past, cassava was categorized as
either sweet or bitter, signifying the absence or
presence of toxic levels of cyanogenic glucosides.
Sweet cultivars can produce as little as 20 mg of HCN
per kg of fresh roots, while bitter ones may produce
more than 50 times as much