Les descripteurs qualitatifs ont été toujours négligés dans les études de caractérisation du cocotier surtout chez les écotypes de type Grand. Cet article se propose de mettre en évidence la contribution de six caractères morphologiques de type qualitatif dans la description et la typologie de 18 populations de cocotier Grand plantées dans la collection internationale de Côte d’Ivoire. Pour y arriver les stipes, les inflorescences, les fleurs femelles et les fruits ont été observés. Compte tenu à la fois de leurs fortes valeurs d’indice de diversité de Shannon normalisé (H’ variant entre 0,93 et 0,99) et faibles valeurs d’indice de diversité de Simpson (D variant entre 0,24 et 0,28), les caractères formes du fruit et de la noix débourrée ont été les plus discriminants. Les résultats de la classification des populations de cocotier Grand de la collection de Côte d’Ivoire utilisant les caractères qualitatifs sont en désaccord avec la structuration admise et fournie antérieurement à partir des marqueurs morphologiques quantitatifs et moléculaires microsatellites (SSRs). Bien que longtemps marginalisé dans l’étude de la diversité génétique des écotypes Grand de cocotier, l’apport des caractères qualitatifs dans l’identification de ces accessions de la collection de Côte d’Ivoire est discuté. Aussi, l’intérêt du recours aux descripteurs qualitatifs comme alternative aux marqueurs moléculaires pour le suivi de la pureté des accessions de cocotier au champ pendant les cycles de régénération est souligné.© 2020 International Formulae Group. All rights reserved. English abstract Qualitative morphological descriptors have always been neglected in coconut population’s characterization, especially in Tall coconut varieties. This paper proposes the contribution of six qualitative traits in the description and typology of 18 Tall coconut populations planted at the international field genebank of Côte d'Ivoire. Relatively to high values of standardized index of Shannon Weaver diversity H' (0.93 to 0.99) and low values of Simpson diversity index D (0.24 to 0.28), the two qualitative traits that are fruit and husked nut shapes were more discriminating. The results about clustering of the Tall coconut populations in Côte d'Ivoire genebank using all studied qualitative characters were in disagreement with the clustering assumed and provided before from quantitative traits and SSRs molecular markers. Although a long time marginalized in the genetic diversity studies, the contribution of the qualitative traits in the identification of Tall coconut populations in international field genebank of Côte d’Ivoire has been discussed. Also, the interest of recourse of the qualitative descriptors as alternative to the molecular markers for purity follow-up of the coconut accession during the cycles of field genebank regeneration is clearly underlined.

Daramcoum et al., J. Appl. Biosci. 2017 Diversité agro-morphologique précoce d'hybrides d'autofécondation F3 de cocotier impliquant l'écotype Nain Vert Sri Lanka (NVS) tolérant à la maladie du Jaunissement Mortel. 11052Journal of Applied Biosciences 112: 11045-11051 ISSN 1997-5902 Diversité agro-morphologique précoce d'hybrides d'autofécondation F3 de cocotier (Cocos nucifera L.) impliquant l'écotype Nain Vert Sri Lanka (NVS) tolérant à la maladie du Jaunissement Mortel 11053ABSTRACT Early agro-morphological diversity assessment in self-pollination coconut (Cocos nucifera L.) hybrids F3 involving Sri Lanka Green Dwarf (SGD) ecotype tolerant to Lethal Yellowing (LY) disease of Ghana Objectives: To obtain morphological diversity precociously in self-pollination dwarf coconut cross generations created in Côte d'Ivoire, mature hybrid seeds and seedlings were studied. Indeed, in coconut palm where the period between planting and fruiting times varies from 3 years, the full morphological characterization at the field takes a long duration. Methodology and results: Twenty-one morphological traits measured on the mature hybrid seeds and seedlings from F3 CRD x SGD, F3 PILD05 x SGD and F2 MYD x MYD (control) hybrids were studied. The results revealed two morphological clusters as different genetic pools which one gathers self-pollination hybrids F3 implying the ecotype Sri-Lanka Green Dwarf (SGD) tolerant to the Lethal Yellowing (LY) disease and the other control cross F2 MYD x MYD sensitive to LY. Three types of morphological traits (types I, II and III) implied in the differentiation of the tolerant and sensitive hybrids relatively to LY disease were also identified. Conclusion and implementation of the results: For Côte d'Ivoire coconut breeding program, these two identified genetic pools and the quantitative traits that characterize them could be exploited in the research of the QTLs associated with LY disease tolerance in coconut palm.

The aim of this study was to investigate the transmission of the lethal yellowing disease (LYD) of coconut tree caused by a phytoplasma from the zygotic embryo to the regenerated plantlet in vitro. From a total of 30 trees, 150 mature coconut nuts where harvested. These nuts were used to extract 150 zygotic embryos. From this package, 96 zygotic embryos were used to regenerate 96 young coconut seedlings in vitro and the 54 others were used to extract total DNA. From the stem of the 30 palms at the stage 1 of the LYD, phloem sample were also collected. From the regenerated in vitro-plantlets at 6 months age, leaf sample were collected. From the molecular diagnosis by PCR, 80% of the phloem samples carried the 16S rRNA gene of the phytoplasma responsible for LYD. All the zygotic embryos and in vitro-plantlets regenerated were healthy. So, coconut zygotic embryos can be used for the safe exchange of genetic material regarding lethal yellowing disease. The regenerated in vitro plantlet are free of disease.

This study endeavour assesses agromorphological likeness between initial introductions and regenerated accessions at the International Coconut Genebank for Africa and the Indian Ocean (ICG-AIO) based in Côte d'Ivoire. Ten couples of parental (G0) and regenerated (G1) accessions of Tall coconut palms were analyzed using Principal Component Analysis (PCA) and Multiple Analysis of Variance (MANOVA) from 26 agromorphological characters. The main results showed a relative decrease in the expression of the phenotypical traits concerning the component of the fruit, height and vigor of the stem and yield of bunches and fruits after one regeneration cycle. But, a high proportion (69%) of studied characters from leaf, inflorescence and nut components showed likeness between G0 and G1 accessions. After one regeneration cycle, the controlled pollination method guarantees significant conservation of the expression of the majority of agromorphological traits. Consequently, regenerated accessions of Tall coconut palms can be used to pursue research and development programs in Côte d'Ivoire.