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

Abstract

Rice (Oryza sativa L.) stands as the most significantly influential food crop in the developing world, with its total production and yield stability affected by environmental stress. Drought stress impacts about 45% of the world’s rice area, affecting plants at molecular, biochemical, physiological, and phenotypic levels. The conventional breeding method, predominantly employing single pedigree selection, has been widely utilized in breeding numerous drought-tolerant rice varieties since the Green Revolution. With rapid progress in plant molecular biology, hundreds of drought-tolerant QTLs/genes have been identified and tested in rice crops under both indoor and field conditions. Several genes have been introgressed into elite germplasm to develop commercially accepted drought-tolerant varieties, resulting in the development of several drought-tolerant rice varieties through marker-assisted selection and genetically engineered approaches. This review provides up-to-date information on proof-of-concept genes and breeding methods in the molecular breeding era, offering guidance for rice breeders to develop drought-tolerant rice varieties.