The wild ancestor of cultivated pearl millet, P. violaceum, is harvested as a wild cereal during times of scarcity. Archaeological evidence suggests that it was harvested as a wild cereal before the advent of agriculture in tropical west Africa some 3000 to 4000 years ago. Genetic evidence points to west Africa as the most likely region of domestication; the earliest archaeobotanical finds are in Mauritania and Nigeria, dating to about 1000 bc. Sporadic records of pearl millet occur at Indian archaeological sites from about 2000 bc.
Pearl millet is an important grain crop in Africa and India. It tolerates drought and heat and grows mainly under rainfed conditions, and thus has a vital role on land too dry for sorghum or corn. It is mostly consumed as a porridge or gruel in Africa and as flat unleavened bread in India. The stalks are used for thatching and building. In other parts of the world (the United States, Canada, and Australia) it is grown as a green fodder crop and as feed grain for animals. As with finger millet, pearl millet is in danger of being displaced by crops, such as corn, that have been the subject of successful crop improvement programs.
See: Origins and Spread of Agriculture, p. 19 Rice Oryza sativa
Rice is the staple food of about half the world's population, mainly in Asia, and is now cultivated in most areas that have abundant water and hot summers. The history of rice domestication is still unclear. Its wild ancestor, O. rufipogon, grows throughout south and southeast Asia, and finds of rice at early sites in the region may derive from harvesting of wild grain. Dating of sites is often unclear. The earliest records of domesticated rice are probably those from the Yangtze river valley of southern China, dating to about 8000 to 6000 14C years ago. There are two main groups of rice varieties: the japonica group, which has short grains, and the indica group, which has long grains. Genetic evidence suggests that each group may have been independently domesticated. However suggestions that indica rice was domesticated in northeast India are not supported by archaeological evidence, which dates the first rice cultivation in the Indian subcontinent to about 2500 bc. It was cultivated in the Near East in the Hellenistic period (from 300 bc) and was traded throughout the Roman empire. However its cultivation in southern Europe did not begin until the medieval period. Rice was also a late arrival in Japan, coming from Korea at the beginning of the Yayoi culture in 400 bc. Archaeological and historical evidence suggests that rice spread slower than most crops, in part owing to its specialized need for abundant water. For example, rice did not become an important crop in North America until the late 17th century.
In dry or upland cultivation, rice is grown on hillsides as a rainfed crop similar to other cereals. Dry cultivation is mainly important in South America and Africa. In wet or lowland systems, most important in Asia, rice is grown on irrigated or flooded paddies. The seeds are often sown in a nursery and then transplanted into paddies. Deep-water rice is grown in water 30 inches (50 cm) or more deep, and is important in Bangladesh and other areas with deeply flooded river valleys. The rice plant has fast-growing stems that grow in pace with the rising water, up to a maximum of 14 feet (4 m). Much of the nutrition for deep-water rice is provided by the silt deposits borne by the flood water.
After harvest, rice must be dehusked to remove the inedible hull (lemma and palea). This is often carried out using a wooden mortar and pestle. The resulting grains are usually eaten as white, polished rice from which the bran has been removed. Whole "brown" rice is mainly popular as a "health food" in Western countries. Rice is most often consumed as whole grains boiled or steamed in water. Rice flour lacks gluten and so is usually consumed as noodles; this absence of gluten results in poor quality bread. Rice cultivars with starch that is low in amylose are waxy or glutinous, and are used industrially as a thickening agent for sauces and puddings, and in East Asia for snack foods such as rice crackers and cakes. In India rice is often parboiled prior to dehusking. This partially cooks the starch, which eases dehusking and milling.
Red rice (O. glaberrima) was an important locally domesticated cereal in west and central tropical Africa, but is increasingly being replaced by the Asian rice (O. sativa), which reached Africa in the 16th century. The wild ancestor of red rice, O. barthii, was probably domesticated in the valley of the Niger river 2000 to 3000 years ago.
Was this article helpful?