Sorghum, a grass of east African origin, is said to have present as early as 8000 years ago. The timing of the emergence of the domesticated sorghum, Sorghum bicolor from the wild species progenitor is disputed with dates ranging from 3700-4900 years ago to not much before 2000 years ago.[i]
Four main groups can be identified within the sorghum family: grain sorghums such as milo, grass sorghums cultivated for pasture and hay, sweet sorghums (also known as Guinea corn) used in the production of sorghum syrups and broomcorn (for brooms and brushes).
[i] Sorghum was introduced into the western hemisphere in the early sixteenth century, and is now an important crop in the United States and Mexico.Read here.