Drought-Tolerant Rice at Molecular Breeding Eras: An Emerging Reality

Rice (Oryza sativa L.) is the most important food crop consumed by the developing world. Whereas the total production and yield stability is largely affected by the environmental stresses. Drought stress affects about 45% of the world’s rice area. Drought stress has been drawn a great attention in the past half century due to its frequently occurrence and costly impacts. Drought stress affects plant at molecular, biochemical, physiological and phenotypic levels. Conventional breeding method of singly pedigree selection was commonly used to breed a numbers of drought-tolerant rice varieties since Green Revolution. As plant molecular biology progresses rapidly, hundreds of drought tolerant QTLs/genes were discovered and tested in rice crop under both indoor and field condition. A number of drought tolerant rice varieties were developed through mark-assisted selection and genetically engineered approaches. Several genes were introgressed into elite germplasm to develop commercially accepted drought tolerant varieties. This review provids up-to-dated information on proof-of-concept genes and breeding methods in molecular breeding eras, which could be used for rice breeders to develop drought-tolerant rice variety.