Résumé
The effect of germination conditions on the morphology of Coffea arabica L. somatic embryos mass-produced in a one-litre temporary immersion bioreactor (RITA7) was studied with emphasis on direct sowing in soil. Using germinated embryos, direct sowing resulted in a highly successful conversion of embryos into plants. Culture density above 1,600 embryos/11-bioreactor positively affected embryo morphology by causing higher embryonic axis elongation (+4-5mm). At this density, addition of a high sucrose concentration (234 mM), 2 weeks before sowing, promoted an increase in effective plant conversion in soil (78%) and a vigorous vegetative growth of the resulting plants. Using this somatic embryogenesis process, 50 000 selected F1 hybrids were recently difunded in America Central. (Résumé d'auteur)