Development of an innovative production system for compact and branched horticultural plants to better respond to emerging urban markets -IRRADIANCE project

This issue deals with the results of winning projects in 2017 and 2018 from the CASDAR (Compte d'Affectation Spéciale Développement Agricole et Rural) call for projects, ‘Innovation and Partnership’ and ‘Technological Research. These projects are funded by the Ministry of Agriculture and Food.

International audience

anglais. Urban space devoted to plants is becoming increasingly limited (balconies, terraces, etc.), and this is accompanied by an increasing demand for compact and branched plants by the consumer. As part of the STRATège Mixed Technology Unit program, the IRRADIANCE project (2018-2022), carried out by ASTREDHOR in partnership with the Research Institute on Horticulture and Seeds (IRHS-INRAE, Institut Agro, University of Angers), aimed to develop a new production system to meet this demand. To achieve this objective, the first phase, carried out in a climatic chamber, enabled compact, branched young plants to be produced more rapidly, thanks to the addition of far-red light (FR). However, in rose, used as a model plant in this project, a genotype-specific response to FR was shown, with some varieties showing no response at all. This insensitivity might result from the accumulation of abscisic acid in the stems and the leaves, inhibiting the stimulating effect of FR on photosynthesis. The young plants, produced in climatic chamber by the Research Institute on Horticulture and Seeds, were grown in greenhouse at ASTREDHOR stations until they reached the commercial stage. A positive effect of this new cultivation system was demonstrated on rose architecture, with more compact plants compared to a traditional cultivation system. A genotype-specific response was also highlighted, justifying the reasoning of the varietal choice for this cultivation system. In collaboration with a growers' cooperative, this new cultivation system was evaluated on other horticultural species and demonstrated its genericity.