Root Functional Phenomics: Using High-Throughput Phenotyping, Targeted Physiology Experiments, and Simulation Modelling to Understand Soil Resource Acquisition

Increasing the ability of crops to acquire soil resources such as water and nitrogen will contribute to future yield gains and mitigation of environmental degradation due to fertilizer pollution. Roots are the interface of plants with the soil, yet little is known about which root phenes, or elemental units of phenotype, have the greatest impact on soil resource acquisition. Root functional phenomics addresses this knowledge gap by using a pipeline consisting of: ideotype development, phenotyping platform design, phenotyping populations, genetic analysis, statistical tests of root relations to crop performance, and the use of targeted physiology experiments and simulation modelling to validate root phene utility. This presentation will highlight progress made in the Root Phenomics Lab to extend the numbers and types of root phenes measured in high-throughput assays. RhizoVision-Crown is a new $1200 root crown phenotyping platform that combines a backlight, a monochrome camera, and camera control software to efficiently image excavated root crowns. A new C++ image analysis program allows fast processing of images to extract features used for downstream statistical analysis. While root system architecture defines the soil region in which roots forage, root segment-level uptake kinetics of nutrients are equally important to determine the overall efficiency of a root system. We describe a new phenotyping platform for measuring uptake kinetics across germplasm that will eventually allow the simultaneous uptake kinetics for all plant nutrients to be measured across entire mapping populations. Finally, results from a greenhouse physiology experiment confirm the utility of reduced nodal root number in maize for increasing lateral root length, nitrogen uptake, rooting depth, and shoot mass by excising nodal roots as they emerge. Roots undoubtedly influence crop performance, and application of the root phenomics pipeline is a promising approach to discover root phenes, validate their utility, and breed for optimal root system phenotypes.