Rice is the seed of the grass species Oryza sativa. As a cereal grain, it is the most widely consumed staple food for a large part of the world's human population. Since sizable portions of sugarcane and maize crops are used for purposes other than human consumption, rice is the most important grain with regard to human nutrition and caloric intake, providing more than one-fifth of the calories consumed worldwide by humans. There are many varieties of rice and culinary preferences tend to vary regionally. The annual production of rice is about 600 thousand tons which is grown in Marmara and Black Sea regions of Turkey. Rice is the staple food of over half the world's population. It is the predominant dietary energy source for 17 countries in Asia and the Pacific, 9 countries in North and South America and 8 countries in Africa. Rice provides 20% of the world’s dietary energy supply.