Genotype × Light Quality Interaction on Rose Architecture

Laurent Crespel,Camille Le Bras,Thomas Amoroso,Philippe Morel,Mateo Gabriel Unda Ulloa,Soulaiman Sakr

doi:10.3390/agronomy10060913

Abstract

Plant shape, and thereby plant architecture, is a major component of the visual quality of ornamental plants. Plant architecture results from growth and branching processes and is dependent on genetic and environmental factors such as light quality. The effects of genotype and light quality and their interaction were evaluated on rose bush architecture. In a climatic growth chamber, three cultivars (Baipome, Knock Out® Radrazz and ‘The Fairy’) with contrasting architecture were exposed to three different light spectra, using white (W), red (R), and far-red (FR) light-emitting diodes (LEDs), i.e., W, WR, and WRFR. The R/FR ratio varied between treatments, ranging from 7.5 for WRFR to 23.2 for WR. Light intensity (224.6 μmol m−2 s−1) was the same for all treatments. Plants were grown up to the order 1 axis flowering stage, and their architecture was digitized at two observation scales—plant and axis. Highly significant genotype and light quality effects were revealed for most of the variables measured. An increase in stem length, in the number of axes and in the number of flowered axes was observed under the FR enriched light, WRFR. However, a strong genotype × light quality interaction, i.e., a genotype-specific response was highlighted. More in-depth eco-physiological and biochemical investigations are needed to better understand rose behavior in response to light quality and thus identify the determinants of the genotype × light quality interaction.

Highlights

Ornamental plants for garden decoration have been commercialized in spring for quite a number of years
A significant genotype × light quality interaction was observed for LA1 and NbA2, due to very contrasting genotypic responses to light quality (Table 4): under was observed under the FR-enriched (WRFR) compared to W, Baipome and
WRFR compared to W, Baipome, and ‘The Fairy’ were characterized by: (i) better elongation, with a lengthening of LSA3 ranging from +27.4% for Baipome to +38.5% for ’The Fairy’, (ii) better branching, with NbSA3 ranging from +46.3% for ’The Fairy’ to +97.8% for Baipome, and (iii) better flowering, with NbDetSA3 ranging from +50.0% for ‘The Fairy’ to +89.4% for Baipome

Summary

Introduction

Ornamental plants for garden decoration have been commercialized in spring for quite a number of years. Plant architecture depends on genetic and environmental factors, as well as on their interaction [2,3,4]. Plant shape can be genetically controlled by varietal improvement and/or cultivation by environmental control, such as modified light quality [5], water restriction [6,7], or mechanical stimulation [8]. These methods are applied more or less empirically by breeders and horticulturists. More extensive knowledge about the genotype × environment interaction would lead to a more effective control of the plant architecture, and of its shape

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Discussion

Conclusion