Table 1.
Measured and derived root system architecture traits captured by ARIA 2.0 including the 13 which were used to create iRoot categories and for clustering analysis.
| Symbol | Trait name | Unit | Trait description |
|---|---|---|---|
| TRL | Total root length∗ | Cm | Cumulative length of all the roots in centimeters |
| TRL_GR | Total root length growth rate∗ | Cm | Change in total root length |
| PRL | Primary root length∗ | Cm | Length of the primary root in centimeters |
| TRLUpper | Total root length upper∗ | Cm | Total root length of the upper one-third |
| DEP | Depth∗ | Cm | The maximum vertical distance reached by the root system |
| WID | Width∗ | Cm | The maximum horizontal width of the whole RSA |
| CVA | Convex area∗ | cm2 | The area of the convex hull that encloses the entire root image |
| RHZO | Rhizosphere area∗ | cm2 | Length of 2 mm surrounding the TRL |
| VOL | Volume∗ | cm3 | Volume of the primary root |
| LRA | Lateral root angle∗ | Angle | Median root angle along the extent of all lateral roots |
| SOL2 | Solidity (inverse)∗ | Ratio | The fraction equal to the convex area divided by the network area |
| LED | Length distribution∗ | Ratio | TRLUpper/TRLLower |
| NLR | Nodes of lateral roots | Count | Number of nodes of lateral roots |
| IRB | Independent lateral root branches | Count | Number of independent lateral root branches |
| MED | Median | Count | The median number of roots at all Y-location |
| MAX | MaximumR | Count | The maximum number of roots at all Y-location |
| TRArea | Total root area | cm2 | Area of the RSA as observed in the 2D projected view |
| PRA | Primary root surface area | cm2 | Surface area of the primary root |
| TRAUpper | Total root area upper | cm2 | Total root area of the upper one-third |
| TRALower | Total root area lower | cm2 | Total root area of the lower two-thirds |
| WDR | Width/depth ratio | Ratio | The ratio of the maximum width to depth |
| SOL | Solidity | Ratio | The fraction equal to the network area divided by the convex area |
| BSH | Bushiness | Ratio | The ratio of the maximum to the median number of roots |
| SRL/PRL | SRL by PRL | Ratio | Number of the secondary root per unit length of the primary root |
| COM | Center of mass | Ratio | Center of gravity of the root/depth |
| COP | Center of point | Ratio | Absolute center of the root regardless of root length/depth |
| CMT | Center of mass (top) | Ratio | Center of gravity of the top 1/3 of the root (top)/depth |
| CMM | Center of mass (mid) | Ratio | Center of gravity of the middle 1/3 root (middle)/depth |
| CMB | Center of mass (bottom) | Ratio | Center of gravity of the bottom 1/3 root (bottom)/depth |
| CPT | Center of point (top) | Ratio | Absolute center of the root regardless of root length (top)/depth |
| CPM | Center of point (mid) | Ratio | Absolute center of the root regardless of root length (middle)/depth |
| CPB | Center of point (bottom) | Ratio | Absolute center of the root regardless of root length (bottom)/depth |
| Seed weight | Grams | Weight of 100 seeds | |
| Shoot weight | Grams | Dry weight of shoot | |
| Root_weight∗ | Grams | Dry weight of root |
Pixels converted to cm. ∗Root trait used in one or more iRoot categories.