Evaluating UAV captured RGB and multispectral imagery as a proxy for visual rating of leaf spot in cultivated peanut

Abstract

Abstract Leaf spot is a devastating disease in cultivated peanut ( Arachis hypogaea L.) that can lead to significant yield losses without chemical controls. Multiple disease symptoms, two causal organisms, inconsistent testing environments, and genotype by environment interactions are all components that make breeding for leaf spot‐resistant peanuts challenging. To better understand this disease, and make gains in breeding for disease resistance, an accurate and objective phenotyping strategy must be implemented. In this work, data derived from leaf scans, unoccupied aerial vehicle‐captured red, green, blue and multispectral imagery were evaluated as a replacement for the subjective visual rating scale used at present. Standard operating procedures are detailed for all digital methods evaluated in this paper, and all digital phenotypes are fully characterized with descriptive statistics. Feature importance and post hoc proof of concept studies are conducted to further evaluate the new digital methods. Ultimately, “visible atmospherically resistant index” was selected as the most appropriate proxy for visual ratings and should be deployed by researchers and plant breeders in the peanut community for the objective evaluation of leaf spot resistance.

Plant phenotyping relevance

落花生葉斑病の客観的表現型評価を目的に、葉スキャンおよびUAVのRGB・マルチスペクトル画像を用いるデジタル手法を評価・標準化しており、病害表現型の取得法が中心である。

Code and data availability

The paper deposits its phenotyping datasets (visual ratings, leaf scans, UAV RGB/multispectral imagery) in Dryad and hosts analysis scripts and supporting information in a public GitHub repository, both explicitly linked by the authors.