Canopy Roughness: A New Phenotypic Trait to Estimate Aboveground Biomass from Unmanned Aerial System

Monica Herrero-Huerta; Alexander Bucksch; Eetu Puttonen; Katy M Rainey

doi:10.34133/2020/6735967

Canopy Roughness: A New Phenotypic Trait to Estimate Aboveground Biomass from Unmanned Aerial System

Plant Phenomics. 2020 Dec 8:2020:6735967. doi: 10.34133/2020/6735967. eCollection 2020.

Authors

Monica Herrero-Huerta^{1

2

3}, Alexander Bucksch^{4

5

6}, Eetu Puttonen⁷, Katy M Rainey¹

Affiliations

¹ Department of Agronomy, Purdue University, West Lafayette, IN, USA.
² Department of Cartographic and Land Engineering, Higher Polytechnic School of Avila, University of Salamanca, Avila, Spain.
³ Institute for Plant Sciences, College of Agriculture, Purdue University, West Lafayette, IN, USA.
⁴ Department of Plant Biology, University of Georgia, Athens, GA, USA.
⁵ Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA, USA.
⁶ Institute of Bioinformatics, University of Georgia, Athens, GA, USA.
⁷ Finnish Geospatial Research Institute, National Land Survey of Finland, Masala, Finland.

Abstract

Cost-effective phenotyping methods are urgently needed to advance crop genetics in order to meet the food, fuel, and fiber demands of the coming decades. Concretely, characterizing plot level traits in fields is of particular interest. Recent developments in high-resolution imaging sensors for UAS (unmanned aerial systems) focused on collecting detailed phenotypic measurements are a potential solution. We introduce canopy roughness as a new plant plot-level trait. We tested its usability with soybean by optical data collected from UAS to estimate biomass. We validate canopy roughness on a panel of 108 soybean [Glycine max (L.) Merr.] recombinant inbred lines in a multienvironment trial during the R2 growth stage. A senseFly eBee UAS platform obtained aerial images with a senseFly S.O.D.A. compact digital camera. Using a structure from motion (SfM) technique, we reconstructed 3D point clouds of the soybean experiment. A novel pipeline for feature extraction was developed to compute canopy roughness from point clouds. We used regression analysis to correlate canopy roughness with field-measured aboveground biomass (AGB) with a leave-one-out cross-validation. Overall, our models achieved a coefficient of determination (R ²) greater than 0.5 in all trials. Moreover, we found that canopy roughness has the ability to discern AGB variations among different genotypes. Our test trials demonstrate the potential of canopy roughness as a reliable trait for high-throughput phenotyping to estimate AGB. As such, canopy roughness provides practical information to breeders in order to select phenotypes on the basis of UAS data.