Fig. 5

Genome-wide association analysis of total wood glucose yield (TWG). a Manhattan plot for total wood glucose yield (TWG). Each point indicates location of a SNP along the 19 chromosomes of Populus tremula. The blue horizontal line indicates the q-value level of 0.1. The least significant SNPs (P-values > 0.05) have been omitted for plot clarity. b–j Tree height, diameter at breast height (DBH) and TWG in relation to their SNP genotype for the three most significant associations for TWG. Boxplots show phenotypic values of height, diameter and TWG amongst allele classes for the SNPs with the smallest p-values in the association tests; chr1_28056992_G_A had the highest statistical significance among the SNPs in the chromosome 1 GWAS hotspot for TWG (see also Additional file 4). The jittered points around each box represent median phenotypic values of the SwAsp clonal replicates. Analysis of variance F-ratios and P-values are reported, where the dependent variable is the phenotype and the independent variable is the SNP genotype class The significances are indicated at. < 0.1, * < 0.05, and ** < 0.01. The three traits are shown for the SNPs chr9_2882991_T_C (b–d), chr1_28056992_G_A (e–g) and chr10_2830421_T_G (h–j)