Maize was introduced into Africa by Portuguese traders
in the 15th century, and for a long time it was grown as a
vegetable crop; the cobs were picked and eaten while still
moist. The crop is an important component of the diet in
some countries; in Kenya and Tanzania, for example, maize
contributes about 34–36 percent of the daily caloric intake.
Only in the more recent past have maize grains been treated
like the more traditional grain crops. Millet and sorghum,