Sorghum is a genus of about 25 species of flowering plants in the grass family (Poaceae). Some of these species are grown as cereals for human consumption and some in pastures for animals. One species, Sorghum bicolor, was originally domesticated in Africa and has since spread throughout the globe. Seventeen of the 25 species are native to Australia,[2][3] with the range of some extending to Africa, Asia, Mesoamerica, and certain islands in the Indian and Pacific Oceans.[4][5] One species is grown for grain, while many others are used as fodder plants, either cultivated in warm climates worldwide or naturalized in pasture lands.[6] Sorghum is in the subfamily Panicoideae and the tribe Andropogoneae (the tribe of big bluestem and sugarcane).
One species, Sorghum bicolor,[7] native to Africa with many cultivated forms,[8] is an important crop worldwide, used for food (as grain and in sorghum syrup or "sorghum molasses"), animal fodder, the production of alcoholic beverages, and biofuels. Sorghum's cultivation has been linked by archeological research back to ancient Sudan around 6,000 to 7,000 BP.[9]
All sorghums contain phenolic acids, and most contain flavonoids.[10] Sorghum grains are one of the highest food sources of the flavonoid proanthocyanidin.[11] Total phenol content (in both phenolic acids and flavonoids) is correlated with antioxidant activity.[10] Antioxidant activity is high in sorghums having dark pericarp and pigmented testa.[10] The antioxidant activity of sorghum may explain the reduced incidence of certain cancers in populations consuming sorghum.[10]
Popped sorghum is popular as a snack in India. The popped sorghum is similar to popcorn, but the puffs are smaller.[12] Recipes for popping sorghum by microwave, in a pot, etc., are readily available online.[13][12]
Most varieties are drought- and heat-tolerant, nitrogen-efficient,[15] and are especially important in arid and semi-arid regions, where the grain is one of the staples for poor and rural people. These varieties form important components of forage in many tropical regions. S. bicolor is an important food crop in Africa, Central America, and South Asia, and is the 5th most important cereal crop grown in the world.[16][17]
In the early stages of the plants' growth, some species of sorghum can contain levels of hydrogen cyanide, hordenine, and nitrates, which are lethal to grazing animals. When stressed by drought or heat, plants can also contain toxic levels of cyanide and nitrates at later stages in growth.[18][19]