Table 2. Model performance statistics for external validation.

Averaged R², RMSE, and NRMSE (%) for external validation data generated via regression analysis using 500 random permutations of the data for models predicting leaf traits from maize spectra.

Trait	R2	RMSE	Bias	NRMSE
A (µmol CO2 m−2 s−1)	0.86	6.96	0.70	13
E (mmol water m−2 s−1)	0.89	1.39	0.33	13
gs (mol water m−2 s−1)	0.79	0.08	0.02	15
Ci (µmol mol−1)	0.52	49.54	−11.32	15
WUEi (µmol CO2 mmol−1 water)	0.76	0.77	−0.13	11
WUEin (µmol CO2 mmol−1 water)	0.55	24.54	0.97	15
Tl (°C)	0.79	1.06	0.15	18
ChlSPAD	0.44	2.99	−0.15	17
Ψw (−MPa)	0.40	0.25	0.00	20
Ψπ (−MPa)	0.34	0.10	−0.02	21
Ψπ100 (−MPa)	0.40	0.07	0.00	16
RWC (%)	0.65	6.28	0.80	15
Suc (g g−1)	0.74	0.36	−0.04	14
SLA (cm2 g−1)	0.77	19.87	−0.88	12
TSD (mm−2)	0.37	22.37	−14.87	22