Résumé
Ideotypes are a popular concept for plant breeders, who designate as such the ideal combinations of traits in a particular genotype. This historical, genetic view of ideotypes can (and has) been more recently extended to cover the design of plant genotypes for specific cropping systems (the ‘agronomic’ view), or even the ideal combination of parameters, identified from simulation modeling, to a specific agronomic problem (the ‘mathematical’ view). Designing an ideotype requires first to precisely bind the purpose the ideotype is supposed to meet. This imposes not only the definition of the agronomic problem itself, the action possibilities available (genetic variability in the plant, human interventions during crop husbandry, etc…), but also of the production system considered. Whether ideotypes should remain virtual objects (i.e., cultivar blueprints) or can be real varieties is still an open debate. The different forms of ideotypes in turn induce different strategies for breeding plants. This paper will therefore briefly describe, analyse and discuss the application of these modes of ideotype conception and design in the specific case of architectural traits of plant and plant canopies to limit the epidemic development of pests and diseases in crops.