From pots to plots: Pathways from understanding plant response to drought to crop impact on-farm

A lot of research has been dedicated to better understand plant response to drought. To reduce the complexity of drought, much of that research has been done in pots, leading to a disconnection with field plots, where the impact of this research is expected. This viewpoint clarifies several confusions about drought tolerance of annual crops, and re-establishes a synergistic link between pots and plots. One confusion is between crop's capacity to survive under water limitation and its capacity to sustain growth, although at a limited rate, under water limitation. This confusion derives from the pot protocols that have been designed and widely used to assess plant responses to water limitation, although they differ greatly from the plot reality. The review proposes a drought tolerance definition (higher yield under water limitation in the field), and a drought tolerance framework that cluster traits that may scale up to higher yield under stress in the field, in a context-dependent manner, into five hubs (water demand, water budget size, speed of water use, water use efficiency, timing of water use). There, the question of scaling is critical because many "drought tolerance" traits, measured in pots, have been proposed in the literature, but few only scaled up to yield in the field. For example, a massive body of work has been done on traits to fight against oxidative stress under drought, although this research was unable to scale up at field level. Plants in pots and plants forming a canopy are exposed to very different atmospheric conditions regarding light exposure and evaporative demand. This has important consequences for their physiology and their interactions with the environment, which need to be considered in the interpretation of plant responses to drought in pots. Finally, the disconnection between pots and plots has also overlooked the importance of crop agronomy in the drought response. The last section of the review is then an advocacy to re-look more closely at the potential of agronomic practices to cope with water limitations. Agronomic practices that can contribute to drought tolerance, also in a context-dependent manner, are then mapped to the drought tolerance framework.