CASSAVA

Cassava or manioc (Manihot esculenta) is a woody shrub of the Euphorbiaceae (spurge family) native to South America that is extensively cultivated as an annual crop in tropical and subtropical regions for its edible starchy tuberous root, a major source of carbohydrates.Cassava is the thirdlargest source of carbohydrates for human food in the world, with Africa its largest center of production. The flour made of the roots is called tapioca.

The cassava root is long and tapered, with a firm homogeneous flesh encased in a detachable rind, about 1 mm thick, rough and brown on the outside. Commercial varieties can be 5 to 10 cm in diameter at the top, and 50 to 80 cm long. A woody cordon runs along the root's axis. The flesh can be chalk-white or yellowish. Cassava roots are very rich in starch, and contain significant amounts of calcium (50 mg/100g), phosphorus (40 mg/100g) and vitamin C (25 mg/100g). However, they are poor in protein and other nutrients. In contrast, cassava leaves are a good source of protein if supplemented with the amino acid methionine despite containing cyanide

Wild populations of M. esculenta subspecies flabellifolia, shown to be the progenitor of domesticated cassava, are centered in west-central Brazil where it was likely first domesticated no more than 10,000 years BP By 6,600 BC, manioc pollen appears in the Gulf of Mexico lowlands, at the San Andres archaeological site. The oldest direct evidence of cassava cultivation comes from a 1,400 year old Maya site, Joya de Ceren, in El Salvador. although the species Manihot esculenta likely originated further south in Brazil and Paraguay. With its high food potential, it had become a staple food of the native populations of northern South America, southern Mesoamerica, and the West Indies by the time of the Spanish conquest, and its cultivation was continued by the colonial Portuguese and Spanish. Forms of the modern domesticated species can be found growing in the wild in the south of Brazil. While there are several wild Manihot species, all varieties of M. esculenta are cultigens.

Cassava was a staple food for pre-Columbian peoples in the Americas, and is often protrayed in indigenous art. The Moche people often depicted yuca in their ceramics. Cassava, together with yams (Dioscorea sp.) and sweet potatoes (Ipomea batatas) are important sources of food in the tropics. The cassava plant gives the highest yield of food energy per cultivated area per day among crop plants, except possibly for sugarcane Cassava plays a particularly important role in developing countries’ farming -- especially in sub-Saharan Africa -- because it does well on poor soils and with low rainfall, and because it is a perennial that can be harvested as required. Its wide harvesting window allows it to act as a famine reserve and is invaluable in managing labor schedules. It also offers flexibility to resource-poor farmers because it serves as either a subsistence or a cash crop