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Introduction Phenotypic plasticity is the ability of a single genotype to express multiple phenotypes in response to changes in the environment. It is considered an adaptive strategy in heterogeneous environments [...], Phenotypic plasticity is an adaptive mechanism adopted by plants in response to environmental heterogeneity. Cultivated and wild species adapt in contrasting environments; however, it is not well understood how genetic changes responsible for phenotypic plasticity were involved in crop evolution. We investigated the genetic control of phenotypic plasticity in Asian cultivated (Oryza sativa) and wild rice (O. rufipogon) under 5 environmental conditions (2 nutrient and 3 density levels). Quantitative trait locus (QTL) analysis was conducted for traits affecting plant architecture and biomass production. By analysing the phenotypic means, QTLs of large effects were detected as a cluster on chromosome 7 under all the environmental conditions investigated; this might have contributed to transitions of plant architecture during domestication, as reported previously. Multiple QTLs of plasticity were also found within this QTL cluster, demonstrating that allele-specific environmental sensitivity might control plasticity. Furthermore, QTLs controlling plasticity without affecting phenotypic means were also identified. The mode of action and direction of allele effects of plasticity QTLs varied depending on the traits and environmental signals. These findings confirmed that cultivated and wild rice show distinctive genetic differentiation for phenotypic plasticity, which might have contributed to adaptation under contrasting environmental heterogeneity during the domestication of rice. Key words: Oryza sativa, Oryza rufipogon, domestication, phenotypic plasticity, QTL analysis. La plasticite phenotypique est un mecanisme adaptatif utilise par les plantes en reponse a l'heterogeneite environnementale. Les especes cultivees et sauvages s'adaptent a des environnements contrastes. Cependant, peu de choses sont connues sur les changements geneetiques responsables de la plasticite; phenotypique et qui ont ete impliques dans revolution des especes. Les auteurs etudient le controle genetique de la plasticite; phenotypique chez le riz asiatique cultive; (Oryza sativa) et sauvage (O. rufipogon) dans 5 conditions environnementales (2 niveaux nutritionnels et 3 densites de population). Une analyse des caracteres quantitatifs (QTL) a ete realised pour les caracteres affectant l'architecture de la plante et la production de biomasse. En analysant les moyennes phenotypiques, des QTL majeurs ont ete detectes et ils etaient groupes sur le chromosome 7 pour toutes les conditions environnementales etudiees. Ceci pourrait avoir contribue a la transition de l'architecture de la plante au cours de la domestication, tel que rapporte anterieurement. Plusieurs QTL de plasticitee ont egalement ete trouves au sein de cette region, demontrant que la sensibilite environnementale conferee par les alleles pourrait controller la plasticite;. De plus, des QTL controlant la plasticite; sans affecter les moyennes phenotypiques ont egalement ete; identifies. Le mode d'action et la direction des effets alle;liques sur les QTL de plasticite; variaient selon le caracteere et les signaux environnementaux. Ces observations confirment que les riz cultivees et sauvages affichent une differentiation genetique distincte en ce qui a trait a la plasticite; phenotypique, laquelle pourrait avoir contribue; a l'adaptation a des conditions environnementales heterogenes au cours de la domestication du riz. Mots-cles : Oryza sativa, Oryza rufipogon, domestication, plasticite phenotypique, analyse QTL. [Traduit par la Redaction]