Cassava (Manihot esculenta Crantz) is a perennial crop plant. It is a dicotyledonous plant belonging to the botanical family Euphorbiaceae. It originated in America with a major centre of diversity in South America and secondary centre in Guatemala and Mexico where it had been cultivated for more than 5,000 years (Rogers, 1963; Leon, 1977). It was first grown for food by American Indians. (Chinaka and Ikeorgu, 1995). Cassava has since spread to various parts of the world such that today it is grown in all parts of the tropics. Most of this spread has occurred within the last four centuries.
Cassava was introduced into West Africa by the Portuguese in the 16th Century. The crop was not introduced to East Africa until much later probably in the 18th century. It is the most widely distributed of the tropical root crops. In Nigeria, the crop is widely grown especially in the south where Philips (1977) noted that it has displaced yam to some extent owing to its ability to resist drought and also to produce yields in seemingly poor soils.
Darlington (1969) noted that the crop is relatively new to Africa, though it has been used elsewhere as a food plant since prehistoric times. Its production increased only slowly until the middle of the 19th century, when its ability to withstand locust attack and to tolerate drought, low soil fertility and poor husbandry made it such a valuable famine reserve crop that many territories in which it was grown prescribed minimum acreages which each farmer was required to plant by law (Jones, 1959). Cassava produces acceptable yields on poor soil or depleted soil where other crops yield essentially nothing (Bokanga, 1996). Cassava even when abandoned after planting, produces some yield and thus is regarded as a cheap crop to produce. It is a “famine reserve” crop and can withstand 6 months of drought after establishment.
Cassava is a major staple food crop in South-eastern Nigeria, (Olojede et al., 2002). It constitutes about 93% of the major starchy staples. Cassava is widely accepted by the local farmers and this is attributed to it’s wide of ecological amplitude, such as it’s adaptability to a wide variety of ecological and agronomic conditions (Carter et al., 1992 and Nweke, 1996). The major factors, which influence cassava production and consumption, are ecology, human population density and the market infrastructure (Carter and Jones, 1989). Cassava plant growth is optimal in warm humid climates with deep fertile soils, but the crop is known to tolerate considerably less favourable conditions (Cock, 1985). In many areas, cassava can still be cultivated even after considerable land degradation has taken place. In Nigeria, cassava is present in all zones except in the humid coastal areas, where the soils have salinity problems.
Nigeria through her new agricultural programme plans to boost cassava production up to 33 million metric tons yearly. Nigeria, is rated the world largest producer and consumer of cassava (IITA, 1998; Guardian News paper July 22, 2005). In Nigeria, Kogi state is rated the largest producer of cassava. Because of the importance of cassava in the agricultural sub-sector, the Federal Government has funded a research exercise which produced five high yielding cassava varieties that can adapt to all ecological zones of the country. Adetunji, (2005) reported that Federal Government was set to end farmers experience in the area of glut, low price regimes and post harvest related problems.
Cassava is a crop of world wide economic importance. It is a plant with intriguing characters, a short season perennial crop with uses more diverse than other tuber crops. Cassava is cultivated principally for its cheap food energy. In recent times, it is used as raw material for some agro-allied industries. The Federal Government had directed bakers and other confectionary makers to include 10 percent cassava flour in the production of bread and other allied goods (Guardian Newspaper July 22, 2005).
Cassava root consists of about 15% peel and 85% flesh (Onwueme and Sinha, 1991). For use of human food, the peel is invariably removed and only the flesh is utilized. Both peel and flesh are utilized if the tubers are to be processed for animal feed. The fresh tuber flesh consist of approximately 62% water, 20-25% starch, 1-2% protein and 1-2% fibre, with traces of fat and minerals. The tuber flesh is relatively rich in vitamin C but has only negligible amount of other vitamins (Onwueme and Sinha 1991). Onwueme (1977) noted that the tubers with low hydrocyanic acid can be consumed with little or no processing. Such tubers may be eaten raw as salad or snack, or they may be boiled, then pounded into paste.
Fetuga and Oluyemi (1976) in their works on the metabolic energy of some tropical tuber meals for chicks reported that sweet potato and cassava meals are superior energy sources for chicks when compared with cocoyam, yam and plantain meals.
The leaves of cassava are a significant item of diet in Zaire, Congo, Liberia Sierra Leone and several other African Countries (Terra, 1964; Ownueme and Sinha 1991). Terra (1964) reported that cassava leaves are richer than the roots in both quality and quantity of protein, although differences between cultivars and leaf age are important, giving a percent of the dry matter. A well prepared cassava leaves is very nutritious and contains appreciable amount of proteins, minerals and vitamins (Terra, 1964; IITA, 1979 Onwueme and Sinha 1991, Hahn et al, 1993; Bokanga, 1996 and IITA, 1998).
Cassava leaf meal is nearly equivalent to Alfalfa meal in food value (Khajarem et al, 1977). Apart from the roots which are processed into various local food products, cassava leaf vegetable constitutes a delicacy for majority of the Congolese “Every Congolese family takes cassava leaves in one form or the other at least 3 times a week” (Lema, 2005). The crop is thus considered first in the food economy of the people. Cassava leaves contain as much protein as in eggs (This Day Newspaper June 21, 2005) and safe for human consumption after adequate processing is done in Democratic Republic of Congo (DRC) and other countries. Beer and other alcoholic drinks may be processed from cassava and in Trinidad, sweet cassava is used as a nurse crop for cocoa (Purseglove, 1974).
The cassava storage root can be processed into garri and cassava flour for food. The importance of cassava as a substitute for maize in livestock ration is increasing (Caveness, 1981; Obioha and Anikwe 1982). It is also an important source of starch for textiles and other industries.
Cassava root can equally be processed into cassava chips and pellets for large scale use in animal feed. Chips are essentially dried slices of cassava tubers, while pellets are made by grinding the cassava chips and pressing them into cylindrical pieces.
The major constraints in cassava production include, pests and diseases, soil, agronomic and socioeconomic factors as well as high perishability of the roots when harvested.
The objectives of this study were:
- To Evaluate the performance of 12 cassava genotypes in Nsukka agro-ecology.
- To ascertain the storage qualities of cassava chips over time.
- To identify the best genotypes in Nsukka agro-ecosystem.