Rice can be consumed to fulfill the Food Vital needs. It an also be processed into Flour by the Mill, and then into Bread by the Bakery, starting in the Bronze Age.
Like all food crops, Rice require a Civilization Point in Cultural Customs in order to be consumed, and another point in Cultural Skills in order to be grown in farms. It can always be gathered from wild crops without requiring a point investment into Cultural Skills.
Also, like all other Tropical foods, Rice can only be grown in the Tropical climate.
The gather yield of a single tile of wild rice crops is 0.015.
The gather yield of a wheat Field can vary between 0.1 and 0.2 per Field, depending on Fertility.
Both wild crops and fields can be improved to yield more wheat by investing extra Culture Points into rice production.