Fig. 1

Weighted gene co-expression network analysis (WGCNA) of temperature-associated genes in the heat-tolerant and heat-sensitive broccoli genotypes. a Clustering dendrogram of genes showing module membership in colours. The y axis represents network distance as determined by 1 - topological overlap (TO), where values closer to 0 indicate greater similarity of probe expression profiles across samples (experimental treatments). Bottom: the first band shows module membership in colours. Additional bands indicate positive (red) and negative (blue) correlation to 15 °C, 22 °C, and 27 °C (see scale bar in B). b Colours to the left represent the 14 modules in the gene co-expression network. For each module, the heatmap shows module eigengen (ME) correlations to traits (4 groups of experimental treatment). Numbers in each cell report the correlation coefficients and Student asymptotic P value (parentheses) for significant ME-trait relationship. Scale bar, right, indicates the range of possible correlations from positive (red, 1) to negative (blue, − 1). c Relationship between the WGCNA modules (brown and magenta) and the three different temperatures (upper panel) and expression of the corresponding eigengene across the samples in the modules (lower panel). The heatmap (upper panel) and barplot of eigengene expression (lower panel) have the same samples (x axis). Rows of the heatmap correspond to genes, columns to samples; red in the color key denotes overexpression, green underexpression