Current Scenarios, Progress and Prospects of Developing Technologies for Flood-Tolerant Rice in Bangladesh

Abstract Flooding is a major hazard to rice production for the rainfed lowland rice ecosystems in Bangladesh. Flash flood and stagnant flood-prone environments are complex in nature with the predominance of many environmental factors. Submergence and stagnant flood tolerances are controlled by many genes and a number of physiological mechanisms are associated with these tolerances. Two major quantitative trait loci (QTLs) viz SUB1 and SNORKEL were identified representing complete submergence and elongation under stagnant flood stress, respectively. Deployment of flash flooding tolerant QTL SUB1 has led to the development of many submergence-tolerant rice varieties in Asia largely contributing to increased rice production in flood-prone environments. Associated crop management packages have also been developed. Prolonging of growth duration under complete submergence and stagnant flood and lack of stagnant flood tolerances are the potential drawbacks of these varieties. Further research for the development of prolonged submergence and stagnant flood-tolerant high-yielding rice varieties in combination with other abiotic and biotic stress tolerances and acceptable grain qualities are essential. Changed breeding concepts utilizing high-throughput molecular markers and faster forward breeding for population improvement are necessary to produce further high-yielding rice varieties in addition to stress tolerances. In addition, not only rice variety development but also development of associated production packages will also be required in order to increase total productivity in stress-prone areas. This paper reviews the current scenarios, progress and prospects of developing technologies for flood-tolerant rice in Bangladesh.