The PCA of the FTIR spectra in the 1800–800 cm
region (A) of the florets of wheat cultivars Sumai3, FL62R1, and Muchmore in two experimental conditions (i.e. in the presence or absence of Fusarium head blight). Loadings plot (PC1, PC2, PC3, and PC4) of the florets of wheat cultivars using FTIR spectra (B). Each point of the plot is the projection of a spectrum in the principal components PC1– PC2 space (C) and PC3-PC4 (D). Empty symbols (○ = non-inoculated with FHB, and □ = inoculated with FHB) represent the spectra from 4 DAI and filled ones for 10 DAI (● = non-inoculated with FHB), and ■ = inoculated with FHB). The other colors are used for the different cultivars: Sumai3 (light green to dark green), FL62R1 (light blue to dark blue), and (red to brown). The percentages within the parenthesis represent the proportion of variance represented by the principal components. NF: non-infected; F: infected with Fusarium.