Complementary Phenotyping of Maize Root System Architecture by Root Pulling Force and X-Ray Imaging.

Abstract

The root system is critical for the survival of nearly all land plants and a key target for improving abiotic stress tolerance, nutrient accumulation, and yield in crop species. Although many methods of root phenotyping exist, within field studies, one of the most popular methods is the extraction and measurement of the upper portion of the root system, known as the root crown, followed by trait quantification based on manual measurements or 2D imaging. However, 2D techniques are inherently limited by the information available from single points of view. Here, we used X-ray computed tomography to generate highly accurate 3D models of maize root crowns and created computational pipelines capable of measuring 71 features from each sample. This approach improves estimates of the genetic contribution to root system architecture and is refined enough to detect various changes in global root system architecture over developmental time as well as more subtle changes in root distributions as a result of environmental differences. We demonstrate that root pulling force, a high-throughput method of root extraction that provides an estimate of root mass, is associated with multiple 3D traits from our pipeline. Our combined methodology can therefore be used to calibrate and interpret root pulling force measurements across a range of experimental contexts or scaled up as a stand-alone approach in large genetic studies of root system architecture.

Plant phenotyping relevance

トウモロコシ根系のX線CT画像から3Dモデルを構築し、71形質を抽出する計算パイプラインを開発・適用しており、表現型取得手法が研究の中心です。

Code and data availability

The paper's custom image-processing and feature-extraction scripts are publicly available in the Topp-Roots-Lab GitHub repository, explicitly linked by the authors for reproducing the work. The phenotype data (Data File S1) is in supplements without a direct URL, and image volumes are only available upon request.