Sustainably feeding the worlds growing population in future is a great challenge and can be achieved only by increaasing yield per unit land surface. Effciency of light interception and biomass partitioning into harvestable parts(harvest index) ha sbeen improved sustantially via plant breeding in modern crops. The conversion efficiency of intercepted light into biomass still holds promise for yield increase. This conversion efficiency is to a great extent constrained by the metabolic capacity of photosynthesis, defined by the characteristics of its components. Genetic manipulations are increasingly applied to lift these constraints, by improving CO2 or substrate availability for the photosynthetic carbon reduction cycle. Although these manipulations can lead to improved potential growth rates, this increase might be offset by a decrease in performance under stress conditions. In this review, we assess possible positive or negative effects of the introduction of a CO2-concentrating mechanism in C3 crop potential productivity and yield robustness.