Rice (Oryza sativa L.) is an important food crop for a large portion of the world’s population, and it is the staple food for the people of Asia, Latin America, and Africa. Rice is cultivated on all of the continents except Antarctica; it accounts for about 23% of the world’s total land area under cereal production (Wassmann et al. 2009a; Jagadish et al. 2010) and covers more than 161 million ha (with production of about 680 million metric tons). More than 90% of rice is produced and consumed in Asia (Jena and Mackill 2008; Grewal, Manito, and Bartolome 2011; Kumar and Ladha 2011), where this crop’s historical importance is significant. Rice cultivation sustained many civilizations in the river deltas of India, China, and Southeast Asia and has become deeply intertwined with the cultures of these regions (Krishnan et al. 2011).