Millet
Millets are a highly varied group of small-seeded grasses, widely grown around the world as cereal crops or grains for fodder and human food. Most millets belong to the tribe Paniceae.
Millets are important crops in the semi-arid tropics of Asia and Africa, especially in India, Mali, Nigeria, and Niger, with 97% of production in developing countries. The crop is favoured for its productivity and short growing season under hot dry conditions. The millets are sometimes understood to include the widely cultivated sorghum; apart from that, pearl millet is the most commonly cultivated of the millets. Finger millet, proso millet, barnyard millet, little millet, kodo millet, browntop millet and foxtail millet are other important crop species.
Millets may have been consumed by humans for about 7,000 years and potentially had "a pivotal role in the rise of multi-crop agriculture and settled farming societies".
Etymology
The word millet is derived via Old French millet, millot from Latin millium, 'millet', ultimately from Proto-Indo-European *mele-, 'to crush'.Description
Characteristics
Millets are small-grained, annual, warm-weather cereals belonging to the grass family. They are highly tolerant of drought and other extreme weather conditions and have a similar nutrient content to other major cereals.Taxonomic history
In 1753, Carl Linnaeus described foxtail millet as Panicum italicum. Finger millet was described as Eleusine coracana by Joseph Gaertner in 1788. In 1812, Palisot de Beauvois grouped several taxa into Setaria italica.The genus Pennisetum was divided by Otto Stapf in 1934 into the section penicillaria, with 32 species including all the cultivated ones, and four other sections. In 1977, J. Brunken and colleagues classed the wild P. violaceum as part of the cultivated species P. glaucum.
Evolution
Phylogeny
The millets are closely related to sorghum and maize within the PACMAD clade of grasses, and more distantly to the cereals of the BOP clade such as wheat and barley.Within the Panicoideae, sorghum is in the tribe Andropogoneae, while pearl millet, proso, foxtail, fonio, little millet, sawa, Japanese barnyard millet and kodo are in the tribe Paniceae. Within the Chloridoideae, finger millet is in the tribe Cynodonteae, while teff is in the tribe Eragrostideae.
Taxonomy
The different species of millets are not all closely related. All are members of the family Poaceae, but they belong to different tribes and subfamilies. Commonly cultivated millets are:Eragrostideae tribe in the subfamily Chloridoideae:
- Eleusine coracana: Finger millet
- Eragrostis tef: Teff; often not considered to be a millet
- Genus Panicum:
- * Panicum miliaceum: Proso millet
- * Panicum sumatrense: Little millet
- * Panicum hirticaule: Sonoran millet, cultivated in the American Southwest
- Cenchrus americanus: Pearl millet
- Setaria italica: Foxtail millet, Italian millet, panic
- Genus Digitaria: of minor importance as crops
- * Digitaria exilis: known as white fonio, fonio millet, and hungry rice or acha rice
- * Digitaria iburua: Black fonio
- * Digitaria compacta: Raishan, cultivated in the Khasi Hills of northeast India
- * Digitaria sanguinalis: Polish millet
- Genus Echinochloa: collectively, the members of this genus are called barnyard grasses or barnyard millets
- * Echinochloa esculenta: Japanese barnyard millet
- * Echinochloa frumentacea: Indian barnyard millet
- * Echinochloa stagnina: Burgu millet
- * Echinochloa crus-galli: Common barnyard grass
- Paspalum scrobiculatum: Kodo millet
- Genus Urochloa
- * Urochloa deflexa: Guinea millet
- * Urochloa ramosa: Browntop millet, southern India
- Spodiopogon formosanus: Taiwan oil millet, endemic to Taiwan
- Sorghum bicolor: Sorghum; usually considered a separate cereal, but sometimes known as great millet
- Coix lacryma-jobi: Job's tears, also known as adlay millet
Domestication and spread
Millet was growing wild in Greece as early as 3000 BC, and bulk storage containers for millet have been found from the Late Bronze Age in Macedonia and northern Greece. Hesiod states that "the beards grow round the millet, which men sow in summer." Millet is listed along with wheat in the third century BC by Theophrastus in his Enquiry into Plants.
East Asia
Proso millet and foxtail millet were important crops beginning in the Early Neolithic of China. Some of the earliest evidence of millet cultivation in China was found at Cishan, where proso millet husk phytoliths and biomolecular components have been identified around 10,300–8,700 years ago in storage pits along with remains of pit-houses, pottery, and stone tools related to millet cultivation. Evidence at Cishan for foxtail millet dates back to around 8,700 years ago. Noodles made from these two varieties of millet were found under a 4,000-year-old earthenware bowl containing well-preserved noodles at the Lajia archaeological site in north China; this is the oldest evidence of millet noodles in China. During the Late Neolithic and Bronze Age, a majority of the cereals consumed during the Zhengluo region of China were foxtail millet and proso millet. Chinese myths attribute the domestication of millet to Shennong, a legendary emperor of China, and Hou Ji, whose name means Lord Millet.Palaeoethnobotanists have found evidence of the cultivation of millet in the Korean Peninsula dating to the Middle Jeulmun pottery period. Millet continued to be an important element in the intensive, multicropping agriculture of the Mumun pottery period in Korea. Millets and their wild ancestors, such as barnyard grass and panic grass, were also cultivated in Japan during the Jōmon period sometime after 4000 BC.
Indian subcontinent
Little millet is believed to have been domesticated around 3000 BC in the Indian subcontinent and Kodo millet around 3700 BC, also in the Indian subcontinent.Pearl millet had arrived in the Indian subcontinent by 2000 BC to 1700 BC.
Browntop millet was likely domesticated in the Deccan near the beginning of the third millennium BCE and spread throughout India, though was later superseded by other millets.
Cultivation of Finger millet had spread to South India by 1800 BC. Various millets have been mentioned in some of the Yajurveda texts, identifying foxtail millet, Barnyard millet and black finger millet, indicating that millet cultivation was happening around 1200 BC in India.
Africa
Finger millet is native to the highlands of East Africa and was domesticated before the third millennium BC. Pearl millet was domesticated in the Sahel region of West Africa from Pennisetum violaceum. Early archaeological evidence in Africa includes finds at Birimi in northern Ghana and Dhar Tichitt in Mauritania and the lower Tilemsi valley in Mali. Studies of isozymes suggest domestication took place north east of the Senegal River in the far west of the Sahel and tentatively around 6000 BC.Europe
Broomcorn or proso millet came to Europe from East Asia as early as the 17th century BC in Vinogradnyi Sad, Ukraine. At around 1500 BC it reached Italy and southeastern Europe; around 1400 BC it came to central Europe, and from 1200 BC, it arrived in northern Germany.Agriculture
Cultivation
Pearl millet is one of the two major dryland crops in the semiarid, impoverished, less fertile agriculture regions of Africa and southeast Asia. Millets are not only adapted to poor, dry infertile soils, but they are also more reliable under these conditions than most other grain crops.Millets, however, do respond to high fertility and moisture. On a per-hectare basis, millet grain production can be 2 to 4 times higher with use of irrigation and soil supplements. Improved varieties of millet with enhanced disease resistance can significantly increase farm yield. There has been cooperation between poor countries to improve millet yields. For example, 'Okashana 1', a variety developed in India from a natural-growing millet variety in Burkina Faso, doubled yields. This variety was selected for trials in Zimbabwe. From there it was taken to Namibia, where it was released in 1990 and enthusiastically adopted by farmers. 'Okashana 1' became the most popular variety in Namibia, the only non-Sahelian country where pearl millet—locally known as mahangu—is the dominant food staple for consumers. 'Okashana 1' was then introduced to Chad. The variety has significantly enhanced yields in Mauritania and Benin.
Upon request by the Indian Government in 2018, the Food and Agriculture Organisation of the United Nations declared 2023 as International Year of Millets.
Pests and diseases
Millets are subject to damage by many insect pests, including corn borers, stemborers, the caterpillars of numerous moths in the families Erebidae and Noctuidae, the millet midge, many species of flies in the Muscidae, as well as Hemipteran bugs of many families including aphids, and species of thrips, beetles, and grasshoppers.Among the many diseases of millets are serious fungal infections such as anthracnose, blast, charcoal rot, downy mildew, ergot, grain mould, rust, and sheath rot. Bacterial diseases are generally less serious; they include bacterial leaf spot, leaf stripe and leaf streak. Viral diseases are again generally less serious, except for a few diseases such as maize stripe virus, maize mosaic virus, sorghum red stripe virus, and maize streak virus.