Sorghum, first tamed in Sudan, weeds its own fields with chemistry
Sorghum releases a compound called sorgoleone that holds back competing weeds, one reason smallholder farmers can grow it with no fertiliser or other inputs. Domesticated in eastern Sudan more than 5,000 years ago, it is now the fifth most important cereal on Earth, behind rice, wheat, maize and barley.
Sorghum bicolor, also called great millet, jowar, milo or Guinea corn, is a stout grass whose clumps can pass 4 metres, with bushy seed heads holding up to 3,000 small grains. Its wild ancestor was tamed in eastern Sudan near the Atbara and Gash rivers; finds near Kassala date to 3500 to 3000 BCE, and sorghum bread from Predynastic Egyptian graves, about 5,100 years old, is displayed in Turin. The English name comes via Italian sorgo, possibly from a Latin phrase meaning grass of Syria.
The first domesticated form had tight husks that had to be stripped off by force. It reached India around 4,000 years ago and West Africa around 3,000 years ago, and cultivation produced races with bigger, free-threshing grains, including caudatum in the Sahel and durra, probably in India. A wetter period in parts of the Horn of Africa, lasting roughly from 2,500 to 1,000 years ago, helped sorghum farming feed complex societies such as Aksum. Medieval Arab agriculture carried it as far as Spain.
Most varieties tolerate drought, heat and poor soils with pH from 5.0 to 8.5, and they grow best between 12 and 34 degrees Celsius over a season of 115 to 140 days. Improved cultivars in India raised yields enough to free 7 million hectares for other crops. In 2023 the world produced 57 million tonnes, with the United States growing 14 percent. Young plants and drought-stressed ones can carry enough cyanide and nitrates to kill grazing animals.
Uses stretch far beyond porridge and flatbread. Grains pop into a smaller popcorn than maize, and sorghum is a key ingredient in Kaoliang, the clear Chinese spirit, and in sour malwa beer from South Africa. Sweet sorghum stalks yield syrup and ethanol, with an energy ratio similar to sugarcane. Nigerians have dyed leather with its red leaf sheaths, and Indian brooms use its panicle stalks as bristles.
Source: Sorghum
