Phenotyping Crop Root Crowns: General Guidance and Specific Protocols for Maize, Wheat, and Soybean.

Root crown phenotyping allows measuring many parameters that describe the top portion of crop root systems and can be used for the basis of genome-wide association studies, QTL analysis, and physiology studies. Root crown phenotyping is a relatively simple process, with the major steps being excavation, transport, soil removal, and measurements. On the other hand, all steps require substantial manual labor and occur outside in challenging environments, and many factors influence the ultimate success of applying this methodology to research questions. Here, general guidance is given for how to optimize root crown phenotyping for unique research questions, and specific protocols are given for acquiring images of root crowns of three crop species: maize, wheat, and soybean.