DROPS will develop novel methods and strategies aimed at yield maintenance under fluctuating water deficit and at enhanced plant water-use efficiency. We deal with high genotype x environment interaction in the field (any trait can have positive, negative or no effect depending on drought scenarios) with an approach combining Physiology, Genetics, field testing and Ecophysiological modelling. The project targets four traits : seed abortion, vegetative growth maintenance, root system architecture and transpiration efficiency. It deals with maize and durum wheat, plus bread wheat and sorghum for specific tasks. DROPS will: - Develop new screens for identifying drought tolerant genotypes, from phenotyping platforms to the field with indicators which are (i) stable characteristics of genotypes with high heritability in phenotyping platforms (ii) based on novel knowledge (e.g. combinations of metabolite concentrations, sensitivity parameters of models or hormonal balances) (iii) genetically related to target traits and able to predict genotype performance in the field via simulation and/or statistical models. - Explore the natural variation of the four target traits by (i) linking the target traits to physiological pathways, genes or genomic regions (ii) assessing the effects of a large allelic diversity for the four target traits via association genetics. - Support crop improvement strategies by developing methods for estimating the comparative advantages of relevant alleles and traits in fields with contrasting drought scenarios. This will be performed via field experiments and by developing a new generation of crop model able to estimate the effects of alleles on crop growth, yield and water-use efficiency Results and methods will be diffused (i) to breeders via the participation of seed companies and a partnership with a breeder association, (ii) to scientists and students via academic publications, and via practical courses and virtual courses in its website.