Résumé
Root systems play a pivotal role in determining plant's competitive ability through their capacities to acquire and store resources. A better understanding of the role of the root system and its plasticity in determining the ability of cultivated species to cope with competition is essential for optimizing resource utilization in changing environments. Domestication and the highly artificial conditions of post green revolution cropping systems have likely influenced the plasticity of crop genotypes and their competitiveness. In this study, we investigate whether domestication has altered the value and plasticity of root traits in durum wheat and the connections between these modifications and the plant's response to competition.We utilized a collection of 39 genotypes representing four key stages (wild ancestors, first domesticated, landrace, and elite) in the domestication of durum wheat. These genotypes were grown in pots in a common garden experiment, both individually and alongside the same competitive genotype. We measured above- and belowground functional traits as well as performance traits to assess competitive responses. Our findings reveal a significant impact of domestication on trait values, plasticity, and competitive responses across the four compartments. In response to competition, all compartments reduced their specific root length values, and wild ancestors notably increased their root diameter. Interestingly, despite exhibiting lower plasticity in root traits, the three domesticated compartments experienced less biomass loss in response to competition compared to wild ancestors. Our results raise questions about the role of traits plasticity in plant’s ability to tolerate competition and their evolution during the domestication of cultivated species.