Table 3.
Description of 38 root-related traits and four shoot traits in 184 wheat genotypes characterized in a semi-hydroponic phenotyping system
| Trait | Abbreviation | Description | Unit |
|---|---|---|---|
| Seminal root length zone1 | SRLZ1 | The longest seminal root length at branching zone (Z1) | cm |
| Seminal root length zone2 | SRLZ2 | The longest seminal root length at non-branching zone (Z2) | cm |
| Maximal root depth | MRD | The longest seminal root length (i.e., root depth, Z1 + Z2) | cm |
| Seminal and primary root number | SRN | Seminal and primary root number (from seeds) | number per plant |
| Total root length | RL | Total root length per plant | cm |
| Root diameter | RD | Average root diameter | mm |
| Total root area | RA | Root surface area | cm2 |
| Total root volume | RV | Root volume | cm3 |
| Root length density | RLD | Root length per unit area (0–110 cm depth, 1430 cm2) | cm cm−2 |
| Specific root length | SRL | Total root length per unit root dry mass | m g−1 dry mass |
| Root length Intensity | RLI | Total root length per unit root depth | cm cm− 1 |
| Root tissue density | RTD | Root dry mass per unit root volume | mg cm−3 |
| Diameter class length | DCL | Root length within a diameter class | mm |
| Relative diameter class length | rDCL | Root diameter class length/Total root length | % |
| Root length s1 | RL_s1 | Total root length in section 1 (s1, 0–20 cm; top-root layer) | cm |
| Root diameter s1 | RD_s1 | Average root diameter in section 1 (s1, 0–20 cm) | mm |
| Root area s1 | RA_s1 | Total root surface area in section 1 (s1, 0–20 cm) | cm2 |
| Root volume s1 | RV_s1 | Total root volume in section 1 (s1, 0–20 cm) | cm3 |
| Root length density s1 | RLD_s1 | Root length per unit area in section 1 (s1, 260 cm2) | cm cm−2 |
| Root length s2 | RL_s2 | Total root length in section 2 (s2, 20–40 cm) | cm |
| Root diameter s2 | RD_s2 | Average root diameter in section 2 (s2, 20–40 cm) | mm |
| Root area s2 | RA_s2 | Total root surface area in section 2 (s2, 20–40 cm) | cm2 |
| Root volume s2 | RV_s2 | Total root volume in section 2 (s2, 20–40 cm) | cm3 |
| Root length density s2 | RLD_s2 | Root length per unit area in section 2 (s2, 260 cm2) | cm cm−2 |
| Root length s3 | RL_s3 | Total root length in section 3 (s3, 40–110 cm) | cm |
| Root diameter s3 | RD_s3 | Average root diameter in section 3 (s3, 40–110 cm) | mm |
| Root area s3 | RA_s3 | Total root surface area in section 3 (s3, 40–110 cm) | cm2 |
| Root volume s3 | RV_s3 | Total root volume in section 3 (s3, 40–110 cm) | cm3 |
| Root length density s3 | RLD_s3 | Root length per unit area in section 3 (s3, 910 cm2) | cm cm−2 |
| Root length in sub-root layer | RL_sub | Combined root length in sub-root layer (s2 & s3) | cm |
| Root diameter in sub-root layer | RD_sub | Combined average root diameter in sub-root layer (s2 & s3) | mm |
| Root area in sub-root layer | RA_sub | Total root surface area in sub-root layer (s2 & s3) | cm2 |
| Root volume in sub-root layer | RV_sub | Total root volume in sub-root layer (s2 & s3) | cm3 |
| Root length density in sub-root layer | RLD_sub | Root length per unit area in sub-root layer (s2 & s3) | cm cm−2 |
| Root length ratio | RLR_s1/sub | Root length in section 1 (top-root layer) over sub-root layer | |
| Root growth rate | RGR | Average daily root growth (based on the longest seminal or primary root growth at 35 days after seed sowing) | cm d−1 |
| Root mass | RM | Root dry mass | mg |
| Shoot mass | SM | Shoot dry mass | mg |
| Total dry mass | TDM | Total dry mass (sum of root and shoot dry mass) | mg |
| Root mass ratio | RMR | Root-to-shoot dry mass ratio | |
| Shoot height | SH | Shoot height measured to the tallest leaf | cm |
| Leaf number | LN | Number of leaves per plant | |
| Tiller number | TN | Number of tillers per plant |