Using Thermography to Confirm Genotypic Variation for Drought Response in Maize.

Abstract

The feasibility of thermography as a technique for plant screening aiming at drought-tolerance has been proven by its relationship with gas exchange, biomass, and yield. In this study, unlike most of the previous, thermography was applied for phenotyping contrasting maize genotypes whose classification for drought tolerance had already been established in the field. Our objective was to determine whether thermography-based classification would discriminate the maize genotypes in a similar way as the field selection in which just grain yield was taken into account as a criterion. We evaluated gas exchange, daily water consumption, leaf relative water content, aboveground biomass, and grain yield. Indeed, the screening of maize genotypes based on canopy temperature showed similar results to traditional methods. Nevertheless, canopy temperature only partially reflected gas exchange rates and daily water consumption in plants under drought. Part of the explanation may lie in the changes that drought had caused in plant leaves and canopy structure, altering absorption and dissipation of energy, photosynthesis, transpiration, and partitioning rates. Accordingly, although there was a negative relationship between grain yield and plant canopy temperature, it does not necessarily mean that plants whose canopies were maintained cooler under drought achieved the highest yield.

Plant phenotyping relevance

熱画像サーモグラフィーを用いた作物表現型スクリーニングを、既知の乾燥耐性分類と比較して検証しており、方法の適用・妥当性評価が研究の中心です。

Code and data availability

The paper's supplementary materials (hosted at the MDPI supplement URL) explicitly contain paper-specific phenotyping assets: weather data recorded during the experiment (Supplementary File 1), UAV/thermal-imager setup (File 2), the mean-shift segmentation procedure (File 3), segmented canopy masks (File 4), and the un