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Table 3 Description of 38 root-related traits and four shoot traits in 184 wheat genotypes characterized in a semi-hydroponic phenotyping system

From: Phenotypic variability in bread wheat root systems at the early vegetative stage

TraitAbbreviationDescriptionUnit
Seminal root length zone1SRLZ1The longest seminal root length at branching zone (Z1)cm
Seminal root length zone2SRLZ2The longest seminal root length at non-branching zone (Z2)cm
Maximal root depthMRDThe longest seminal root length (i.e., root depth, Z1 + Z2)cm
Seminal and primary root numberSRNSeminal and primary root number (from seeds)number per plant
Total root lengthRLTotal root length per plantcm
Root diameterRDAverage root diametermm
Total root areaRARoot surface areacm2
Total root volumeRVRoot volumecm3
Root length densityRLDRoot length per unit area (0–110 cm depth, 1430 cm2)cm cm−2
Specific root lengthSRLTotal root length per unit root dry massm g−1 dry mass
Root length IntensityRLITotal root length per unit root depthcm cm− 1
Root tissue densityRTDRoot dry mass per unit root volumemg cm−3
Diameter class lengthDCLRoot length within a diameter classmm
Relative diameter class lengthrDCLRoot diameter class length/Total root length%
Root length s1RL_s1Total root length in section 1 (s1, 0–20 cm; top-root layer)cm
Root diameter s1RD_s1Average root diameter in section 1 (s1, 0–20 cm)mm
Root area s1RA_s1Total root surface area in section 1 (s1, 0–20 cm)cm2
Root volume s1RV_s1Total root volume in section 1 (s1, 0–20 cm)cm3
Root length density s1RLD_s1Root length per unit area in section 1 (s1, 260 cm2)cm cm−2
Root length s2RL_s2Total root length in section 2 (s2, 20–40 cm)cm
Root diameter s2RD_s2Average root diameter in section 2 (s2, 20–40 cm)mm
Root area s2RA_s2Total root surface area in section 2 (s2, 20–40 cm)cm2
Root volume s2RV_s2Total root volume in section 2 (s2, 20–40 cm)cm3
Root length density s2RLD_s2Root length per unit area in section 2 (s2, 260 cm2)cm cm−2
Root length s3RL_s3Total root length in section 3 (s3, 40–110 cm)cm
Root diameter s3RD_s3Average root diameter in section 3 (s3, 40–110 cm)mm
Root area s3RA_s3Total root surface area in section 3 (s3, 40–110 cm)cm2
Root volume s3RV_s3Total root volume in section 3 (s3, 40–110 cm)cm3
Root length density s3RLD_s3Root length per unit area in section 3 (s3, 910 cm2)cm cm−2
Root length in sub-root layerRL_subCombined root length in sub-root layer (s2 & s3)cm
Root diameter in sub-root layerRD_subCombined average root diameter in sub-root layer (s2 & s3)mm
Root area in sub-root layerRA_subTotal root surface area in sub-root layer (s2 & s3)cm2
Root volume in sub-root layerRV_subTotal root volume in sub-root layer (s2 & s3)cm3
Root length density in sub-root layerRLD_subRoot length per unit area in sub-root layer (s2 & s3)cm cm−2
Root length ratioRLR_s1/subRoot length in section 1 (top-root layer) over sub-root layer 
Root growth rateRGRAverage daily root growth (based on the longest seminal or primary root growth at 35 days after seed sowing)cm d−1
Root massRMRoot dry massmg
Shoot massSMShoot dry massmg
Total dry massTDMTotal dry mass (sum of root and shoot dry mass)mg
Root mass ratioRMRRoot-to-shoot dry mass ratio 
Shoot heightSHShoot height measured to the tallest leafcm
Leaf numberLNNumber of leaves per plant 
Tiller numberTNNumber of tillers per plant 
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