Résumé
Rubber tree breeding has been handicapped from the outset by the impossibility of obtaining self-rooted clones or rootstock clones. CIRAD has been working on rubber tree in vitro culture since the 1980s and has developed different vegetative micropropagation procedures, by somatic embryogenesis and microcutting of selected mature clones. Two new varietal types have been created: self-rooted and budded rejuvenated clones. Since 1989, 65 ha of validation field trials with a statistical design have been conducted in three Asian and African countries to assess the vegetative development and natural rubber yield of trees obtained by in vitro culture, in comparison with conventional mature budded clones. The analysis is based on the usual agronomic parameters in force in rubber estates and also involves phenotypic or genomic characteristics associated with rejuvenation and/or the in vitro procedure. The potential for improving selected clones growth and yield by micropropagation is confirmed here for self-rooted clones and also for rejuvenated budded clones both from microcutting or primary somatic embryogenesis. Conversely, data are still unsatisfactory for vitroplants from maintained somatic embryogenesis. These concrete results reveal prospects for short-term development with the rejuvenated budded clones on the one side, and for medium term development with the other systems. (Résumé d'auteur)