Effect of the genotype × cultivation system interaction on rose architecture

The recent emergence of new closed cultivation systems such as vertical farming and plant factories offers the opportunity to finely control environmental factors like light, temperature, or relative humidity. In ornamental horticulture, this would allow year-round production of plants with good visual quality – compact and branched – in particular when growing conditions are unfavourable while the market demand (for Christmas/New Year/Valentine’s day) is high. The effects of genotype and cultivation system (greenhouse vs. climatic chamber) were evaluated on rose bush architecture. Three cultivars (‘Baipome’, Knock Out^® ‘Radrazz’ and ‘The Fairy’) with contrasting architecture were grown in spring in two different cultivation systems: i) a greenhouse, and ii) a climatic chamber. Significant genotype and cultivation system effects were revealed for most of the measured variables. An increase in stem length, in the number of axes and the number of flowered axes was observed for the plants grown in the climatic chamber. However, a strong genotype × cultivation system interaction was highlighted due to very contrasting genotypic responses. Taken together, genotype × cultivation system interactions need to be evaluated before developing any new cultivation systems in order to choose the best-suited genetics.