N	Nitrogen
SPAD	Relative leaf chlorophyll content
HTTP	Hight throughput plant phenotyping
UAV	Unmanned aerial vehicle
VNIR	Visible and near-infrared
NDVI	Normalized difference vegetation index
SR	Simple ratio
NDWI	Normalized difference water index
RGB	Red–green–blue
RGB VIs	Red–green–blue vegetation indices
UAV RGB VIs	Unmanned aerial vehicle red-green-blue vegetation indices
Ground RGB VIs	Ground level red-green-blue vegetation indices
HIS	Hue–intensity–saturation
H	Hue
GA	Green area
GGA	Greener green area
CSI	Crop senescence index
CIMMYT	International center for maize and wheat improvement
OP	Optimum nitrogen
LOW	Low managed nitrogen
L*	Lightness
NDLab	Normalized difference between a* and b*
NDLuv	Normalized difference between u* and v*
TGI	Triangular greenness index
NGRDI	Normalized green–red difference index
ASI	Anthesis silking interval
AD	Anthesis data
PH	Plant height
SEN	Canopy senescence
MOI	Moisture
GY	Grain yield
GYLI	Grain yield loss index
HY	High yield
MHY	Medium high yield
MLY	Medium low yield
LY	Low yield
ANOVA	Analyses of variance