Résumé
Clonal propagation of oil palm (#Elaeis guineensis# Jacq) through somatic embryogenesis has been practiced for more than 20 years by the French ORSTOM-CIRAD group. A micropropagation process has been developed at pilot scale in four production units spread over three producing countries. The technique has been proven by field performances on more than 2,500 ha of clonal plantations. Scaling-up of the current process has revealed several bottlenecks which are now limiting the commercial development of the tissue culture process. The main difficulties encountered at the pilot scale are (1) the production costs and (2) the occurrence of variant palms (ca 5%) in embryogenically derived plant material. The development of oil palm embryogenic cell suspension has been achieved and will certainly enable the large-scale propagation of selected genotypes at low cost. Studies have been conducted in order to improve medium-term conservation of somatic embryos derived from embryogenic suspensions, and the vigour of the regenerated plant material. This new process is currently assessed in terms of genetic fidelity. In order to understand the phenomena underlying the determinism of somaclonal variation, molecular approaches are now being developed in our group involving studies on DNA structure together with patterns of genome expression in the regenerated plant material. The limitations in scaling-up, which have been identified at the pilot scale, have stimulated the implementation of new research programs in plant and seed physiology and in molecular biology. Results expected from these programs will be used for setting up an improved production protocol based on culture of embryogenic suspensions, along with a quality control for genetic fidelity. (Résumé d'auteur)