HIGH-THROUPUT PHENOTYPING OF NITROGEN RESPONSE AND USE IN WHEAT WITH LEMNATEC SCANALYZER 3D

High-throughput phenotyping of nitrogen (N) response and N-use efficiency (NUE) in crop plants is still a developing genre. Because the methods could be variable depending on target traits, growth conditions and species, standardizing phenotyping protocols for N-related traits is challenging. The aim of the project is to establish a high-throughput phenotyping method for quantifying NUE in wheat which could be applied to different species and labs/facilities. We have measured growth response of 8 different wheat cultivars from Australia and Mexico with several N treatments using the Plant Accelerator, the automated non-destructive high-throughput imaging facility, equipped with the LemnaTec Scanalyzer 3D. Daily images were taken from early tillering to heading stage of wheat plants grown in pots. The visible light (RGB) image was used for biomass estimation, and RGB and/or ?uorescence images were employed to assess leaf colour changes during the growth period. Based on the image analysis, a typical N response curve in biomass was observed among all cultivars tested (N treatment: 10-450 mg N /kg soil). At the highest N treatment (450 mg N) only Mace, an Australian modern cultivar, kept a positive correlation between growth and N input, whereas other Australian cultivars did not positively respond. This finding corresponded with the final grain yield with only Mace increasing grain yield with increasing N. The set of historic Mexican varieties from CIMMYT revealed a trend showing that newer varieties grew faster and larger compared with older varieties at a given N concentration indicating an improvement in N use through selection by breeders. N-deficiency symptoms were assessed by leaf colour image analysis revealing that the degree of deficiency symptoms varied between the cultivars. These results indicate that high-throughput phenotyping during the mid-growth stage could be useful to identify genetic variations in N use in wheat, and potentially in other species.