Climate predictions for Europe indicate that scenarios of severe drought combined with intense temperatures observed during the summer of 2022 are likely to become the norm by 2050. In this context, sorghum appears as an alternative to maize, more tolerant to stress. However, this reputation is based on few studies and few genotypes, which would ideally represent ‘maize’ and ‘sorghum’ as species. The main hypothesis of the project ‘TRIES’ is that these differences in stress tolerance would result from more intense selection pressure in maize than in sorghum, maximizing maize yields in optimal conditions but making it more sensitive to stress. These reputations could be questioned by exploring the genetic diversity of each species, and thus potentially the wide range of traits that confer resistance to water and heat stress available in each species. ‘TRIES’ brings together a highly complementary consortium, including two research units (LEPSE and AGAP institute), the applied research institute ARVALIS, and a public research group managing large trial networks for variety registration (GEVES). It proposes an approach at the forefront of plant design, plant physiology, and modeling, to provide the first large-scale comparative study of maize and sorghum of this magnitude, from intra- and inter-specific variability of stress-related traits to the definition of trans-species ideotypes (weather found in sorghum or maize) for current and future European stress scenarios. ‘TRIES’ will first (i) sort out facts regarding the actual and assumed tolerances of maize and sorghum by conducting a large-scale comparative study of field performance of elite materials from the past 15 years in well-characterized environmental scenarios. (ii) These results will then be challenged by comparative analyses in the field, with a genetic diversity comprising different genetic groups and generations of selection, to test hypotheses related to the impact of selection effort, contrasting precocities between sorghum and maize, and crop management. (iii) Performances in the field will be related to the intra- and inter-specific diversities of processes controlling yield response to abiotic stress, ranging from leaf and root growth, transpiration controls, and cold tolerance, which imposes sowing dates and earliness of genotypes in each region. All these traits will be extracted from high-throughput experiments in phenotyping platforms. The analysis of the relationships between traits will indicate the links between these processes, their breeding trajectories, as well as the opportunities not exploited by selection but available in the genetic diversity of these species. (iv) Finally, ‘TRIES’ will develop a generic model capable of predicting the performance of trans-species ideotypes (whether found in maize or sorghum) sought in intra- and inter-specific diversities accessible through selection and adapted to local scenarios in current and future European climates. Overall, ‘TRIES’ will contribute to the general effort aimed at meeting societal demand to reduce water withdrawals by agriculture, by offering a new quantitative vision of the respective genetic potentials of maize and sorghum under non-irrigated conditions, from the underlying mechanisms to yield under stress conditions, and proposing adaptation strategies to the selection-evaluation-recommendation continuum.