Schematic representation of maize root system development and the aeroponics growth system used to facilitate root phenotyping. (A) The primary root (PR) and seminal roots (SR) initiate from the embryo. (B) Lateral roots (LR) initiate from PR and SR, while crown roots (CR) initiate from the stem. (C) The root system in adult maize consists of a large number of crown roots and their LR, which undergo multiple orders of branching. The various root organs terminate in root hairs (RH). Structural brace roots (BR) initiating above ground are also shown. (D-F) The aeroponics growth system used in this study. (D) Picture showing the highly branched maize root system. (E) The custom built aeroponics chambers. (F) Modern maize tb1-ref plants (B73 background) (left) and inbred B73 (right) at 30 days after transplanting in the aeroponics system. Abbreviations: co = coleoptile; DAG = Days after germination.