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Malgre son importance socioeconomique, la production ivoirienne de noix de cola est confrontee a plusieurs difficultes. Le manque de techniques culturales eprouvees constitue une des contraintes pour la domestication et la culture du colatier. Il est donc necessaire de mettre au point des techniques adaptees a l’espece cultivee. L’objectif de cette etude est d’optimiser la methode de bouturage sous tunnel du colatier (Cola nitida), face aux inconvenients de la multiplication generative. Le dispositif experimental utilise est un Split-Splot avec deux facteurs : le genotype avec cinq modalites (5 genotypes) et le nombre de feuilles avec cinq (05) modalites (1, 2, 3, 4 et 5 feuilles diminuees de moitie). Nous avons le genotype en grande parcelle et le nombre de feuilles en petite parcelle. L’aptitude des genotypes au bouturage a ete evaluee a six mois a travers le taux de survie et la mesure des parametres de croissance et de developpement. Le genotype L18A1D9 a montre la meilleure aptitude au bouturage avec un taux de survie de 41,7%. Les boutures avec 4 feuilles diminuees de moitie ont eu le meilleur taux de survie (41,7%), un bon enracinement des boutures vivantes (88,9%), une biomasse totale fraiche (4,2 g) et totale seche (1,7 g) elevee. Le succes du bouturage sous tunnel du colatier est tributaire du genotype et du nombre de feuilles. Le nombre de feuilles recommande par bouture est de quatre (4) pour le bouturage du colatier sous tunnel. Mot cles : Bouturage, nombre de feuilles, Cola nitida, genotype. Englsih Title: Influence of genotype and number of leaves on the growth in nurseries of cola cuttings (Cola nitida [Wind.] Schott and Endlicher.) Despite its socio-economic importance, kola nut production faces several challenges. Domestication and cultivation of kola requires the adoption of propagation techniques adapted to the crop species. The objective of this study is to optimize kola (Cola nitida) vegetative propagation by cutting under tunnel. The experimental design used was a split-splot with two factors: genotype with five modalities (5 genotypes,) and leave number with five (05) modalities (1, 2, 3, 4 and 5 leaves cut in half). The ability of genotype to cutting propagation was assessed by measuring growth parameters. The survival rate of the cuttings was evaluated at six months. Root growth, number of new leaves, height gain and biomass were subsequently measured. Genotype L18A1D9 has the best ability for vegetative propagation by cuttings with a survival rate of 41.7%. To optimize vegetative propagation by cuttings under tunnel, 4 leaves cut in half by cuttings must be used for acceptable success rate (41.7%), good rooting (88.9%), a high total fresh biomass (4.2 g) and total biomass (1.7g). The success of kola vegetative propagation depends of genotype and the leave number per cutting. The number of leaves per cuttings recommended per cuttings is four (4) for kola vegetative propagation. Keywords : Cuttings, number of leaves, Cola nitida, genotype.

The assessment of population vulnerability under climate change is crucial for planning conservation as well as for ensuring food security. Coffea canephora is, in its native habitat, an understorey tree that is mainly distributed in the lowland rainforests of tropical Africa. Also known as Robusta, its commercial value constitutes a significant revenue for many human populations in tropical countries. Comparing ecological and genomic vulnerabilities within the species' native range can provide valuable insights about habitat loss and the species' adaptive potential, allowing to identify genotypes that may act as a resource for varietal improvement. By applying species distribution models, we assessed ecological vulnerability as the decrease in climatic suitability under future climatic conditions from 492 occurrences. We then quantified genomic vulnerability (or risk of maladaptation) as the allelic composition change required to keep pace with predicted climate change. Genomic vulnerability was estimated from genomic environmental correlations throughout the native range. Suitable habitat was predicted to diminish to half its size by 2050, with populations near coastlines and around the Congo River being the most vulnerable. Whole-genome sequencing revealed 165 candidate SNPs associated with climatic adaptation in C. canephora, which were located in genes involved in plant response to biotic and abiotic stressors. Genomic vulnerability was higher for populations in West Africa and in the region at the border between DRC and Uganda. Despite an overall low correlation between genomic and ecological vulnerability at broad scale, these two components of vulnerability overlap spatially in ways that may become damaging. Genomic vulnerability was estimated to be 23% higher in populations where habitat will be lost in 2050 compared to regions where habitat will remain suitable. These results highlight how ecological and genomic vulnerabilities are relevant when planning on how to cope with climate change regarding an economically important species.

Description. Coffee cultivation plays an important economic and social role in Côte d'Ivoire. Among the dozens of Coffea species, only Coffea canephora, also known as robusta, is grown in the country. The genetic improvement of this species has been the subject of a selection program set up by the National Center for Agronomic Research (CNRA). This program involves two basic genetic groups, Guinean and Congolese. These groups have been determined using enzymatic markers which are known to be less informative. So little is known about the reliability of the genetic structuring of the parental populations. Objectives. The objective of this work is to refine the genetic structuring of the parental populations used to set up the C. canephora breeding program in Côte d'Ivoire using SNP markers and to relate this structure to test values in the genotypes concerned. Method. Sixty-six individuals representing parental genotypes of the two populations were analyzed using 200 SNPs markers. The parameters of genetic diversity were calculated and then the genetic structure was determined. The yield over four years of production, susceptibility to rust, and bean size have been evaluated. Results of these agronomic traits have been included in this analysis. The Guinean genotypes were crossed with a Congolese tester named 464 and the Congolese individuals were crossed with a Guinean tester 410, for assessing their combining ability. Results. The analysis of molecular variance (AMOVA) revealed that 75% of the total variation was due to variation between populations. Bayesian classification and Principal Coordinates Analysis (PCoA) structure the 66 genotypes into two main groups of Guineans and Congoleses. While the Guinean group appears to be homogeneous, the Congolese group is split into four subgroups of SG1, SG2, B and C. Maximum test values are found for the SG1 and SG2 subgroups. The Guinean group showed lower performance. It is important in this group to select the best progenitors. Conclusions. SNP markers were effective in genetic structuring of the population. This study also allows the identification of a genotype that was not determined. The use of this set of markers will be useful for the control of future progenitors. The same genetic progress can be achieved by crossing SG1 or SG2 with a good Guinean male. It seems important to make a selection among the Guineans before crossing them with a Congolese tester.