Format: ORAL

PONCET, Valrie1; Aquino, Sinara1,2; KIWUKA, Catherine3; TOURNEBIZE, Rémi1; MARRACCINI, Pierre4; MUSOLI, Pascal3, ANTEN, Niels5

1IRD, UMR DIADE, Montpellier, FRANCE; 2Federal University of Lavras, MG, Lavras, BRAZIL; 3NARO, Kampala, UGANDA; 4CIRAD, UMR IPME, Montpellier, FRANCE; 5Wageningen Univ. Wageningen, NETHERLANDS

Understanding how organisms respond to their environment by altering physiological processes will increase our capacity to make predictions about adaptation to global climate change. Adaptive clines have been increasingly studied in plant species within temperate zones to understand adaptation of organism in natural populations. However, they are still poorly understood in tropical environments. Coffeacanephora, cultivated as Robusta, is an interesting tropical tree model to investigate adaptation in the tropics, as it is largely distributed within the range of the lowland tropical rain forests of Africa. In particular, modifications occurring in genes related to abiotic stress tolerance make these genes candidate for enhanced resilience to future climate change. We combined the use of both captured regions sequenced for a set of candidate genes related to drought tolerance [1] and whole genome SNP markers [2]. We provided a comprehensive map of selection signals in the genome of the C. canephora [3] both at the species level and within its major genetic groups. The genotype-environment association suggests regional adaptation to spatially varying environments of the recent past, with a special focus on the Eastern edge of the distribution, in Uganda[4]. More specifically, we found signals of selection tightly linked to several genes involved in response to biotic and abiotic stress and in caffeine biosynthesis. We also observed variation of wild Uganda accessions in both growth and drought tolerance [5] that can be utilised for optimizing breeding programs initiatives to develop drought-tolerant varieties with adequate yield capacity. Our results support the hypothesis of present ecological gradient contributing to the structure of the genetic diversity with variation in adaptive traits. Moreover, assessing the adaptive capacities of the present populations will help to predict their response to future environmental changes. 1-de Aquino 2022 2-Tournebize 2022 3-Salojarvi 2023 4-Kiwuka 2021 5-Kiwuka 2023