Effects of Genotype x Environment Interaction on Plant Architecture in Rose

The shape of an ornamental plant and, therefore, its architecture are critical for its visual quality and are dependent on genetic and environmental factors, such as water supply. The aim of the study was to analyze genotypic responses at the architectural level, in eight rose cultivars ('Blush Noisette', 'Baipome' Pink Gnome (R), 'The Fairy', Hw336, 'Old Blush', Hw20, Hw154 and 'Perle d'Or'), to the alternation of water restriction (-20 kPa) and re-watering (-10 kPa) periods. Six architectural variables were measured at the plant and axis scales by 3D digitalization. Significant genotype effect was observed for all measured variables whereas significant environment effect was revealed only for the length and the insertion of long axes and the number of branching order. A strong genotype x environment interaction (GxE) was highlighted for most of the architectural measured variables. GxE interaction was mainly due to different response amplitudes between watering treatments according to genotype. Two groups of architectural responses of different intensities - weak and strong - were identified.