It depends on where you are. If you want an analogue to corn or wheat, you're looking at sorghum (Sorghum bicolor derived) and/or finger, pearl, or guinea millet where viable (Eleusine spp.) across most of the wooded (and savanna) grasslands. If areas were wet enough like the Guinea coast, African rice (Oryza glaberrima) and irrigation systems became viable, but it rarely dominated a region like rice did in (say) the Mekong Delta. Other, more local cereals like teff (used in Ethiopia) and variants of common grains, I'm not trying to include here because their historic prevalence is unclear. The key thing here is that cereals adapted to summer rains, or constant warm or wet climes, would be the norm; although in southernmost Africa crops like wheat, rye, etc. could do well, nobody took them there, and so people living there when Europeans first arrived were transhumant pastoralist foragers--but to the east, where the summer rain pattern and warmer climes held, sorghum was widespread as were the Bantu-speaking societies who cultivated it.

Beyond cereals, there's an island of Omotic agriculture in NE Africa that is autochthonous as far as we know, around cultivation of the enset (Ensete ventricosum or Abyssinian false banana). In more wooded areas or actual cleared rainforest, one might find more planting agriculture (yams), along with (depending on region) taro and bananas (but I'm not sure about plantains that early) which came from eastern Africa through exchange with Austronesians, and which spread very rapidly because of their starchy, high-calorie nature.

For the overview I'd point you at the Cambridge World History of Food (2000), edited by Kiple and Ornelas, but I can locate work on the specific examples as well.