Noémie DELPOUVE

With the current global changes, it is challenging to understand the mechanisms used by organisms to adequate with their climate. Among the processes helping them to cope with climate change, phenotypic plasticity and genetic adaptation are both able to favour phenotypes matching local conditions. They are remarkably important in trees, because they are sessile and have long generations. If we consider more particularly fruit trees, the question of agricultural production to feed populations is also raised. The team in which my internship is included works on apple trees. Malus domestica has been domesticated from wild apple tree from Central Asia but still exchange genes with other wild species. These wild species can present advantageous genome parts, that could be beneficial in plant improvement, and for that reason their study is of great interest too. Here, two wild species are considered along with the domesticated one. The aim of the internship is to analyse these apple trees responses according to different climates. For that purpose, the trees of five genetic groups from different European regions are placed in four different conditions, corresponding to the forth origin countries environments: Armenia, Denmark, Romania and France (the two firsts conditions were done in 2019 and this year we simulate the last two at Ecotron Foljuif, 77). We try to determine if the different observed phenotypes are the result of a plasticity or a genetic adaptation to the origin conditions. To do that, we measure several phenotypical traits, such as germination rate, height and leaf number. Physiological parameters are also considered, such as chlorophyll, flavonoid and nitrogen content, leaf area and biomass. During the five months with the team, I will help for the experimental setup, take part to the different traits measurement, and analyse the obtained data to shed light on the principal mechanisms allowing the apple trees to match with their environmental conditions.