What became a major food source in africa because of the columbian exchange?

Africa's most important food crop during the Columbian Exchange was sorghum. It was also one of the most important cereal in the world. There are many types of sorghum, but in Africa, the type they widely used is sorghum bicolor. They used it as a syrup, for making soup, animal food, biofuel and even a kind of alcohol. Recently it was found out to be a kind of chemical energy converter.