Abstract
Rice production faces the challenge to be enhanced by 50% by year 2030 to meet the growth of the population in rice-eating countries. Whereas yield of cereal crops tend to reach plateaus and a yield is likely to be deeply affected by climate instability and resource scarcity in the coming decades, building rice cultivars harboring root systems that can maintain performance by capturing water and nutrient resources unevenly distributed is a major breeding target. Taking advantage of gathering a community of rice root biologists in a Global Rice Science Partnership workshop held in Montpellier, France, we present here the recent progresses accomplished in this area and focal points where an international network of laboratories should direct their efforts. Review The root system has the crucial role of extracting nutri-ents and water through a complex interplay with soil biogeochemical properties, and of maintaining these functions under a wide range of stress scenarios to en-sure plant survival and reproduction. This role is made even more important due to increasing climate instabil-ity and limitation of fertilizers and irrigation in cropping systems. Determining the precise contribution of root traits to final grain yield under these scenarios and breeding cultivars harboring root systems adapted to stress profiles prevalent in representative target soil envi-ronments are therefore a priority in the plant breeding research agenda. Long neglected, the biology and ecol-ogy of roots -the "hidden half" -have recently attracted an increasing number of research groups and disciplines ranging from genetics, molecular biology, cell biology, physiology, microbiology,