Rice is the primary food for more than 3 billion people around the world. Approximately one-forth of the global rice crops are grown in rainfed lowland plots that are prone to seasonal flooding. Annual crop loss has been estimated to be more than 1 billion dollar. Submergence due to flash-floods is the key factor limiting yield of lowland rice. Development of submergence tolerant cultivar is a need of the hour to improve the food availability of the people who depend on this fragile lowland ecosystem. This book describing different approaches to solve the problem, which include development of non-invasive screening tool for identification of new germplasm tolerant to submergence and characterization of different biophysical and biochemical marker traits for submergence tolerance which will help in varietal improvement both through conventional breeding and biotechnological means. This book should especially useful to researchers/scientists in agriculture and life science field, who may be utilizing for future breeding or development of submergence tolerant rice cultivars.