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.