Riice is the staple food for 50% of the world's population

When rice seedlings are 25 to 50 days old, they are transplanted to a paddy that has been enclosed and submerged under 2 to 4 inches of water. This water must remain in the field throughout the growing season.

Some academics have argued that the need for organized, reliable irrigation in the cultivation of rice may have influenced the political destiny of Asian cultures — significantly the rapid historical development of a centralized Chinese state.

Rice’s importance has spread beyond central Asia. Just like wheat, rice has become an integral element of a successful agricultural package around the world.

So-called wild rice, which can reach 10 feet in height, grows in shallow marshes and along the shores of streams and lakes throughout North America. Natural stands of wild rice were a staple for Midwestern Native Americans, but the species was never domesticated by them, and never provided the basis of a complex, agricultural economy.

By geographic chance, America inherited a subtly different native grass species to the Asian ancestor of modern commercial rice — and on such coincidences the destinies of millions of people throughout history have turned.