The objective of this paper is to present some physiological tools that could be used to assess the performance and support management of irrigation systems under Mediterranean conditions. These tools are related to carbon isotope discrimination and remote sensing. These practical guidelines were originally provided to breeders of small grain cereals interested in adopting a physiological approach to crop improvement, but could be adapted into performance indicators related to the functioning and service provided by irrigation systems. Some of the most promising tools for fast, reliable characterization of yield-determining traits are discussed from an ecophysiological perspective. We will focus on the practical aspects and limitations of using relevant screening tools or selection criteria.