Physical Integration of Root QTLs with the japonica Genome and Prediction of Probable Candidate Genes for Drought Tolerance in Rice

Drought is becoming an increasingly important constraint limiting world's rice production (Bennett, 2003). About half of the world's rice is grown in rainfed environments where the rainfall is the major source of water sup-

Drought is becoming an increasingly important constraint limiting world＇s rice production （Bennett, 2003）. About half of the world＇s rice is grown in ralnfcd environments where the rainfall is the major source of water supply, and yields may be seriously restricted by water deficit. Drought tolerance, though a complex character resulting from many interacting component traits, depends mainly on root characteristics of the rice plant that directly affects the quantity of water available to the crop in the dry season.