Breeding for flooding tolerance in rice: Advancements and future perspectives

Rice, the resilient grain, is cultivated in different types of ecosystems, from seacoast to hilly areas. Unfortunately, due to climate change, it frequently suffers from submergence stress during its growth period. Anoxic stress at the germination phase, flash flooding during the vegetative phase and water stagnation in low-lying areas are the major types of flooding in rice. When floodwaters rise, rice adapts. Some varieties stretch their stems toward the surface, gasping for air. Others remain dormant, conserving energy, like the FR13A landrace, SUB1 equips rice with underwater endurance. It orchestrates a genetic symphony, fine-tuning metabolic pathways and signalling survival. Some of the promising quantitative trait locus (QTLs) identified are qAG-9-2, which is responsible for anaerobic germination tolerance; qSUB1 for vegetative stage submergence tolerance, and qTIL12 for deep water adaptation. Identifying other novel QTLs and donors helps to breed varieties tolerant to different types of submergence stress. Along with Swarna SUB1, many mega-submergence-tolerant varieties have been developed and released for cultivation in Asia. As we cultivate these versatile survivors, we sow hope for a food-secure future.