Evaluating canopy spectral reflectance vegetation indices to estimate nitrogen use traits in hard winter wheat

Wheat nitrogen use efficiency must be improved to reduce the need for nitrogen (N) fertilizers. This study was conducted to determine if measurement of canopy spectral reflectance (CSR) could be used to non-destructively and indirectly select wheat genotypes with improved N use traits. Canopy spectral reflectance measurements were collected during grain fill in a 299-genotype trial planted near Ithaca, NE in 2012 and 2013, and 28 vegetation indices were calculated from the data. The relationship between vegetation indices (VIs) and nitrogen use (NU) traits was investigated. Vegetation indices were highly heritable in both years and predicted these NU traits: anthesis biomass, mature biomass, grain N yield, grain yield, N harvest index, N utilization efficiency, N uptake efficiency and post anthesis N uptake. One VI, Maccioni, performed most consistently and was significantly related to several NU traits. The results of this study indicate that VIs, particularly the Maccioni index, could be used in wheat breeding programs to non-destructively phenotype for NU traits.