Cassava (Manihot esculentaCrantz) is an important food crop in Côte d'Ivoire. Nonetheless, its production is facing many constraints including the abandonment of landraces, fires, pests and diseases. Such a pressure can cause an erosion of the genetic diversity of cassava and wild relatives. In order to overcome those constraints, collections of traditional varieties were carried out in the Centre-west, South-west and West of Côte d'Ivoire. A total of 159 accessions were used. These accessions were observed using morphological parameter. Morphological characterization was done through multivariate analyses on these 159 accessions to better manage germplasm. Accessions were clustered into three classes with 143 morphotypes and 16 duplicates. Class 1 or Type Sié, composed of 45 accessions, included the majority of accessions that had the least common modalities of collection (yellow flesh, white skin, yellowish phelloderm and orange stem). Analysis of similarity / dissimilarity showed that clusters known as Sié, Bassié djélé4 and Djonan djonan of the current germplasm were close to different groups Cosca4, D14 and 256 of the existing collection. Submitted

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Vine cutting is an effective solution to solve the problem of seed availability in yam cultivation. This study was conducted to improve the recovery and rooting rate of vine cuttings of Dioscorea rotundata. Two-node cuttings from five (5)-month-old hybrid plants were grown in liquid media consisting of phytohormones (AIA 3 and GA 3) and liquid fertilizer (NPK 8-8-8) at different concentrations. Observations were made weekly from the 21st day after transplanting and focused on the survival rate of the cuttings, the number of roots emitted and the number of minitubers initiated. The results obtained showed a significant effect of the different growing media on the survival rate, rooting and production of minitubers. The best survival rates were obtained for cuttings grown in NPK (8-8-8) at 0.25% (100%) and AIA 3 at 25 ppm (93.3%). The highest averages root number was recorded with growing media containing 0.25% NPK 8-8-8 (20.3) and 25 ppm AIA 3 (17.7). Growing media with 0.25% NPK (8-8-8) and 25 ppm AIA 3 provided the highest average numbers of minitubers initiated, respectively 5 and 4.6. Growing medium containing 0.25% NPK 8-8-8 has been identified as the one that allows better roots emission and minitubers production by yam vines cuttings.

L'igname D. rotundata est l'espèce la plus appréciée des consommateurs en Côte d'Ivoire. Cependant, sa production stagne du fait des nombreuses contraintes liées à sa culture notamment les viroses. L'utilisation de variétés améliorées issues de reproduction sexuelle, pourrait contribuer efficacement à une production durable. Ce travail visait à évaluer la période des croisements afin d'accroitre les taux de fructifications chez cette espèce. Au total, 28 croisements intra-spécifiques ont été réalisés en utilisant 4 clones femelles et 7 clones mâles issus de la collection d'ignames du CNRA-Bouaké. Deux plages horaires H1 (de 7h30 à 11h) et H2 (de 11h à 13h30), retenues pour les croisements ont été comparées en vue de déterminer la période optimale de pollinisation. Sur 30061 fleurs pollinisées, 2249 fruits ont été obtenus soit 7,48% avec une variation allant de 1,16 à 51,06% de taux moyen de fructification selon les combinaisons de clones. Les taux de fructifications