(a) Up‐ and down‐regulated gene expression for control (C), high anti‐oxidant (AO) and dwarf, high AO accession (dwarfAO). (b) Mean expression ratio for total gene expression of C, AO and dwarfAO, where green represents down‐regulation, pink represents an up‐regulation of genes in accession C when RMA normalisation to the median was performed. This provides clear visualisation of differing expression of specific genes between three watercress accessions. For example, a gene which is down‐regulated in C will have a green line despite being up‐ or down‐regulated in AO and dwarfAO due to the colour of the line being dependent on expression in C. This aids the visualisation of the change in expression without having to trace the accession back to C. (c) Hierarchical clustering of changes in transcript abundance for C and AO and dwarfAO, performed using TMeV software from normalised expression ratio data. Lilac triangles represent seven different clusters, colour scale indicates signal normalised ratios (red = up‐regulated genes, blue = down‐regulated genes). Only genes with ANOVA significance p ≤ 0.05 are shown.