Sorghum belongs to the Family Poaceae, Subfamily Panicoideae, Supertribe Andropogonodae, Tribe Andropogoneae, Subtribe Saccharinae, Genus Sorghum and Species Sorghum bicolor (L.) Moench. Taxonomically it was first described by Linnaeus in 1753 under the name Holcus. Originally he delineated several species of Holcus, some of which have been later moved to the tribe Avenae, where the generic name Holcus now belongs. In 1794, Moench distinguished the genus Sorghum from genus Holcus. It is a grass species cultivated for its grain, which is used for food for humans, animal feed, and ethanol production. Sorghum is native to Ethiopia. Seventeen of the 25 species are native to Australia, with the range of some extending to Africa, Asia, Mesoamerica, and certain islands in the Indian and Pacific Oceans. All the cultivated sorghum taxa of the world have been classified by inflorescence type, grain and glumes into five races (Durra, Bicolor, Caudatum, Kaffir and Guinea) and intermediates involving all of the pair-wise combinations of the basic races. Sorghum is considered as an often cross-pollinated species, with out-crossing up to 6 % depending on the genotype and growing conditions. There are four main types of sorghum viz., Grain sorghum, Forage sorghum, Sweet sorghum and Biomass sorghum. Fruit is a caryopsis (grain) partially covered by glumes, round and bluntly pointed consists of embryo; endosperm and seed coat consists of pericarp and testa. Coleoptiles and roots emerge from the germinating seeds. Sorghum grain is used for human food and as feed for animals; the plant stem and foliage are used for green chop, hay, silage, and pasture. In some areas the stem is used as building material, and plant remains (after the head is harvested) may be used for fuel. It is a C4 plant with higher photosynthetic efficiency and higher abiotic stress tolerance adapted to a range of environments around the world. Its small genome makes sorghum an attractive model for studying the functional genomics of C4 grasses. Drought tolerance makes sorghum especially important in dry regions such as northeast Africa (its center of diversity), India, and the southern plains of the United States. Genetic variation for micronutrient concentration and its ability to absorb, translocate, and accumulate higher micronutrients in grain makes it an important model for biofortification research. Its high level of inbreeding makes it an attractive association genetics system. Sorghum is one of the cheapest sources of energy and micronutrients, and a vast majority of the population in sub-Saharan Africa and India depend on it for their dietary energy and micronutrient requirement. Sorghum provides more than 50 % of the dietary micronutrients, particularly Fe and Zn, to the low-income group, particularly in rural India where both physical and economic access to nutrient-rich foods is limited. Thus, sorghum is a unique crop with multiple uses as food, feed, fodder, fuel, and fiber. The crop improvement methods depend on the pollination control mechanisms and cultivar options. As mentioned earlier, sorghum is a breeder-friendly crop. One can employ the breeding methods that can be used to improve both self- and cross-pollinated crops with ease in sorghum. This is the reason why one can find sorghum pure line varieties, hybrids, and populations as cultivar options in different parts of the world. Nearly all grain sorghum is harvested as a standing crop with a combine. Combining time will depend on the fall weather and the availability of grain drying facilities. Sorghum grain can be threshed free of the head when the seed moisture is 20-25 percent. The seed is hysiologically mature at even higher moisture levels. The grain sorghum crop can be harvested for high-moisture grain silage. When fed to livestock, its digestibility will be increased by grinding or rolling. High moisture grain sorghum can be combined and ensiled when the grain is about 25-30% moisture. In the early stages of plant growth, some sorghum species may contain levels of hydrogen cyanide, hordenine, and nitrates lethal to grazing animals. Plants stressed by drought or heat can also contain toxic levels of cyanide and nitrates at later stages in growth. In this review article on Origin, Domestication, Taxonomy, Botanical Description, Genetics and Cytogenetics, Genetic Diversity, Breeding, Uses, Nutritional Value and Health Benefits of Sorghum are discussed.
