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Understanding the genetic basis of phenotypic plasticity is crucial for predicting and managing climate change effects on wild plants and crops. Here, we combined crop modeling and quantitative genetics to study the genetic control of oil yield plasticity for multiple abiotic stresses in sunflower. First we developed stress indicators to characterize 14 environments for three abiotic stresses (cold, drought and nitrogen) using the SUNFLO crop model and phenotypic variations of three commercial varieties. The computed plant stress indicators better explain yield variation than descriptors at the climatic or crop levels. In those environments, we observed oil yield of 317 sunflower hybrids and regressed it with three selected stress indicators. The slopes of cold stress norm reaction were used as plasticity phenotypes in the following genome-wide association study. Among the 65,534 tested SNP, we identified nine QTL controlling oil yield plasticity to cold stress. Associated SNP are localized in genes previously shown to be involved in cold stress responses: oligopeptide transporters, LTP, cystatin, alternative oxidase, or root development. This novel approach opens new perspectives to identify genomic regions involved in genotype-by-environment interaction of a complex traits to multiple stresses in realistic natural or agronomical conditions.

Adult chimpanzees produce a unique vocal signal, the pant-grunt, when encountering higher-ranking group members. The behaviour is typically directed to a specific receiver and has thus been interpreted as a ‘greeting’ signal. The alpha male obtains a large share of these calls, followed by the other adult males of the group. In this study, we describe the development of pant-grunting behaviour from the first grunt-like calls of newborn babies to the fully developed pant-grunts in adults. Although babies produce grunts from very early on, they are not directed to others until about 2 months of age. Subsequently, socially directed grunting steadily increases in frequency to peak around 7 months of age, but then decreases again to reach a nadir in older infants and juveniles, while the specificity in use increases. During adolescence, grunt production increases again with grunts given most frequently to socially relevant individuals. As young chimpanzees are closely affiliated to their mothers for the first decade of their lives, we also compared the grunting patterns of mothers and their offspring, which revealed some influences in pant-grunt production. In conclusion, the acquisition of pant-grunting behaviour in chimpanzees is a long-lasting process with distinct developmental phases in which social influences by the mother and other group members are likely to play a role.

International audience; Animal vocal communication, as human language, is primarily a social act. It is therefore legitimate to argue in favor of a coevolution between sociality and vocal complexity in primates. However, in contrast with human language, vocal communication in monkeys and apes, our closest living relatives, has long been described as rigid and strongly genetically determined. In recent years, evidences of vocal flexibility under social influences have nonetheless been provided in nonhuman primates. In this paper, we review those recent findings that challenge the dichotomous view of human versus monkey regarding vocal communication. First, a multi-level approach (sound unit, call type, vocal sequence) of the structure of vocal repertoire reveals a flexible organization which enables a complex encoding of messages in vocal signals. Then, the analysis of the social context of communicative interaction demonstrates its role in the emergence of vocal flexibility in juveniles and adults, both in terms of production and usage. We conclude by emphasizing the need, in the future, for additional comparative studies in order to assess the influence of the characteristics of social system on the degree of communicative flexibility and complexity observed at the species level.; La communication vocale animale, tout comme le langage humain, est avant tout un acte social. Il est donc logique de défendre l’idée d’une co-évolution entre socialité et complexité vocale chez les primates. Pourtant, à l’inverse du langage humain, la communication vocale des singes, nos plus proches cousins vivants, a longtemps été décrite comme rigide et fortement déterminée génétiquement. Depuis quelques années, des preuves de flexibilité vocale sous influences sociales ont néanmoins été apportées chez les primates non-humains. Cet article se propose de passer en revue ces découvertes récentes qui remettent en cause la vision dichotomique homme versus singe en matière de communication vocale. Tout d’abord, une approche multi-niveaux (unité sonore, type de cri, séquence vocale) de la structure du répertoire vocal révèle une organisation flexible permettant un encodage complexe de messages dans les signaux vocaux. Ensuite, l’étude du contexte social de l’interaction de communication atteste de son rôle dans l’émergence de flexibilité vocale chez le jeune et l’adulte, tant en termes de production que d’utilisation. Nous concluons en soulignant la nécessité de multiplier à l'avenir les études comparatives afin d’évaluer l’impact des caractéristiques du système social sur le degré de flexibilité et de complexité communicative observé au niveau de l’espèce

While the gestural communication of apes is widely recognised as intentional and flexible, their vocal communication still remains considered as mostly genetically determined and emotionally bound. Trying to limit the direct projections of linguistic concepts, that are far from holding a unified view on what constitute human language, this thesis presents a detailed description of the pant-grunt vocalisation usage and development in the chimpanzees (Pan troglodytes schweinfurthii) of the Budongo forest, Uganda. Pant-grunts are one of the most social vocalisations of the chimpanzee vocal repertoire and are always given from a subordinate individual to a dominant. The question of how such a signal is used and develops is critical for our understanding of chimpanzee social and vocal complexity in an ontogenetical and phylogenetical perpective. Results suggest that pant-grunt vocalisations can be used in a flexible way, both in their form and usage within a social group. More specifically, chimpanzees seemed to take into account the number and identity of surrounding individuals before producing these vocalisations. At the acoustic level, pant-grunts seem to be very variable vocalisations that corresponded to different social situations commonly encountered. Grunts are one of the first vocalisations produced by babies but they are not first produced in social contexts. Although some modifications of the social grunts form and usage could not entirely be attributed to maturation only, the role of the mother seemed to be restricted. Her direct influence was perhaps more visible in the rhythmic patterns of chorusing events. Taken together, this thesis suggests that chimpanzee vocalisations are more flexible in their usage, production and acquisition than previously thought and might therefore be more similar to gestural communication.