Fig. 5

Genotype groupings influenced variance structure differently within each of the three experiments, with visible and SWIR absorption bands contributing most consistently to the PCs that best distinguish genotype groups. a–c Coefficient of variation for spectra of genotype groups compared to relative measurement uncertainty within each experiment. The measurement uncertainty of the three experiments is separately shown in (d) for comparison. e–g Distribution of samples along PCA dimensions best distinguishing different genotype groups: PC3 and PC4 for the field experiments (e, f), and PC2 (shown versus PC1) for the glasshouse experiment (g). Shaded regions show 95% confidence intervals for each group, i.e. reference samples (UT-WT, EV) versus non-reference samples (PLs, RILs, TLs). h–k Contribution of reflectance at each wavelength to the first 4 PCs in each dataset