Identification of relevant morphological, topological and geometrical variables to characterize the architecture of rose bushes in relation to plant shape

Abstract

EuphyticaPlant shape is a major component of the visual quality of ornamental plants. It is the result of their architectural construction. It can be analyzed by breaking down the plant into entities (axis, metamer) that can be characterized morphologically, topologically and geometrically. Eight bush rose cultivars were selected for their contrasting shapes (from upright to spreading) and their architecture was digitized at two scales, the plant and the axis, differentiating between short and long axes. Thirty-five variables were measured. Measurement acquisition is nevertheless tedious and time-consuming and not really compatible with an analysis involving a large number of individuals. To diminish these constraints, our approach aimed at reducing the number of variables measured, limiting ourselves to the ones most relevant for describing the architecture. A selection of variables was made using the following criteria: to represent the different categories of variables describing the plant architecture; to explain the variability observed; to present the weakest correlation between them. Seven variables were selected: at the plant scale, the number of determined axes, the number of long axes of order 3 and the branching order number; at the long axis scale, the number of metamers and the length of the axis; and at the short axis scale, the basal diameter of the axis and the branching angle of the cord in relation to the vertical axis. Four architectural profiles were differentiated based on these seven variables. Moreover, a high correlation was revealed between some of these architectural variables and a shape descriptor

Genotype × year interaction and broad‐sense heritability of architectural characteristics in rose bush

“…The six variables used in this study to describe the architecture of the eight cultivars were chosen by Crespel et al. () for the following reasons: to represent the different categories of variables that describe the architecture at the plant scale and at the axis scale (morphological, topological and geometric variables); to explain the architectural variability observed; to be less correlated among themselves. …”

“…The plants were placed in a cold chamber at 2°C at the elementary architectural structure stage in order to arrest their growth and thus avoid an experimental bias (Crespel et al. ). Finally, plants were defoliated beforehand in order to facilitate the identification of the axes during digitalization.…”

“…Six variables identified by Crespel et al. () as being relevant to describe plant architecture were measured: (i) at the plant scale, the number of axes determined (i.e. axes that terminate with a flower or flower bud) (NbDetA) and the number of long axes (NbLA) and (ii) at the axis scale, the number of metamers on the long axes (NbMet_LA), the length of the long axes (L_LA), the branching angle of the cord of the long axes in relation to the vertical axis (AngLA/Cord) and the number of branching orders (NbBrO).…”

“…), and Crespel et al. () showed that six variables – at the scale of the plant and the axis – were necessary and sufficient to describe rose architecture and its variations. The aim of this article was to present the initial results on the effects of genotype and year factors, and their interaction, on the six architectural variables selected.…”

Assessing the visual aspect of rotating virtual rose bushes by a labeled sorting task

“…Virtual plant growth can be easily monitored, controlled and stopped with various parameters. Also, architectural parameters of virtual plants can be directly obtained from the modeling process, whereas it is very time-consuming and tedious on real plants (Crespel, Sigogne, Donès, Relion, & Morel, 2013). In addition, using virtual plants does not involve growing costs, and allows taking and moving them readily thanks to data storage devices.…”