Mediterranean climate and soils impose drastic constraints to agriculture. Barley (Hordeum vulgare) is one of the best adapted species to Mediterranean conditions. Climate change and growing Mediterranean population will further increase environmental and anthropic constraints on barley culture in a near future. An urgent objective is therefore to obtain barley varieties with high yield under stress conditions, while maintaining high nutritional quality of edible parts, associating high protein, mineral and fiber content with low contamination. In this context, the use of biostimulants of plant growth may help improving stress tolerance as well as nutritional quality, while limiting the use of classical chemical fertilizers that contribute to soil pollution. Our proposal is based on exploring the genetic diversity of a collection of Mediterranean barley accessions subjected to combined environmental constraints: heavy metals (HM), salinity, drought and pathogens. A collection of representative H. vulgare cultivars from Morocco, Algeria, Tunisia and Egypt as well as wild barley accessions (H. spontaneum) will be screened in the frame of this project. The project will therefore make use of local biodiversity to identify ideotypes maintaining high nutritional quality and low contaminant content even when grown under combinations of biotic and abiotic stresses. Nutritional quality and mineral content of grain and straw of these accessions will be analyzed under combinations of different abiotic (drought, salinity, Cd) and biotic (the fungal pathogen Rynchosporium commune) stresses. Physiological and molecular characterization of genotypes with contrasting phenotypes will shed light on the mechanisms underlying their adaptation to multiple stresses. Biostimulants provided by the private partner Roullier will be tested to evaluate their ability to increase stress tolerance and nutritional quality. This project will bring together the expertise of 9 partners from 5 European and North African Mediterranean countries. It is expected to provide key information on the resilience and quality traits of Mediterranean barley germplasm under stress conditions, which can be used by breeders and farmers to choose their variety depending on a particular agricultural environment. We will identify potential ideotypes for entering breeding programs to reach resilience objectives while preserving nutritional quality. An important scientific output of this project will be a better understanding of the molecular and physiological mechanisms involved in barley nutritional quality and tolerance to combined stresses that will be of great relevance for agronomical and scientific communities.