Aerobic rice: a system-based genetic innovation for low water use and methane mitigation

Conventional flooded rice systems are a major source of methane emissions and are increasingly unsustainable in water-constrained environments, creating increasing pressure to identify alternative production systems. Aerobic rice (AR) has been proposed as one such alternative, with the potential to reduce methane emissions by up to 88% while lowering water demand. However, persistent yield penalties and high variability in performance across seasons and environments constrain large-scale adoption. These limitations reflect a combination of poorly defined target environments, limited availability of high-yielding aerobic-adapted varieties, and the lack of validated, sustainable agronomic practices. We argue that these challenges point to a more fundamental issue: AR has largely been approached through individual technological components rather than as an integrated production system. Current efforts do not adequately account for the physiological constraints of rice under aerobic conditions or the need for agronomic and environmental adaptation at the system level. As a result, AR remains uncompetitive in most tropical production systems. This paper reviews progress in AR research and identifies key bottlenecks across genetics, physiology, modelling and agronomy. We propose an interdisciplinary framework for the next generation of AR systems (AR 2.0) that reframes AR as system-based innovation. The framework emphasizes (i) overcoming inherent rice physiological constraints to water uptake, (ii) developing system-based agronomic practices that sustain soil health and system performance, (iii) accelerating breeding of high-yielding aerobic-adapted germplasm, and (iv) defining suitable target domains where productivity, methane mitigation and associated co-benefits can be jointly achieved.