ANTI-NUTRITIONAL CONSTITUENT OF COLOCASIA ESCULENTA ...

Plants of the genus Colocasia are edIble aroids with large leaves and one or more food­
storing underground stems (corms). The corm is made up of starchy ground parenchyma
with a thick brown skin consisting of central circular leaf scares and scales (Lee, 1999).
Onwueme (1999) observed that the Colocasia esculenta Yar. esculenta is made up of a
central corm, bulky and cylindrical in shape, with not many cormels (Fignre AI-la),
whereas Colocasia esculenta var. antiquorum has a number oflarge cormels arising from a
small, central, globe-shaped corm (Fignre Al-Ib). Amadumbe is classified as Colocasia
esculenta var. Schott (Van Wyk and Gericke, 2000).
Taro (Amadnmbe) has been descnbed as a palatable, glabrate, annual herb. The leave blades
(laminae) are large, 250 to 850 mm in length, 200 to 600 mm in width and 275 to 300 mm in
thickness. The leaflaminae are carried on long, erect leafstalks (Fignre AI-2). The leaf shape
is described as being complete and lanceolate, with the apex tapering to a concave point (Lee,
1999).
Colocasia esculenta is best adapted to a warm, moist environment, ideally tropical or
subtropical areas with long frost free periods. Amadumbe requires an average daily
temperature above 21° C for normal production. High humidity with well-distributed
summer rainfall or supplemental irrigation is ideal, partly because ofthe large, transpiring
surfaces of Amadumbe laminae. Crops are normally grown in low-lying areas ranging
from sea level to 1200 m elevation, only where moist conditions and stable temperatures
generally prevail (Onwueme, 1999). Amadumbe is highly tolerant of saturated soil
conditions, such as those found in wetlands, and artificial drainage ofthese soils is seldom
required. Amadumbe cnltivation does little harm to the wetland ifit is restricted only to the
less sensitive parts of the wetland. This presumes that artificial fertilizers and pesticides
are not used and tillage is carned out by hand. Excessive drainage should be avoided and
the cnltivated area shonld be minimised. (Cnltivation, food & health: amadumbe, n.d.).
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