What crops allowed the Olmec population to grow?

Eventually, the Olmec realized the land around the rivers was good for growing crops. Rivers made it possible for the Olmec to create irrigation systems, and they began to grow a variety of food, such as squash, beans, and maize (a hearty, multi-colored grain similar to corn).

2686-2181 bce-- "egyptian civilization developed along the nile river in large part because the river’s annual flooding ensured reliable, rich soil for growing crops."

1069-664 bce-- "ancient egyptians developed wide-reaching trade networks along the nile, in the red sea, and in the near east."