Fig. 1

Scheme of inferred network structure using the Hill-Climbing (HC) algorithm, with 0.85, threshold; the minimum strength required for an arc to be included in the network. Structure learning test was performed with 2500 bootstrap samples with mutual information as the test statistic with a significance level at \(\alpha\) = 0.01. Labels of the edges refer to the strength and direction (parenthesis) which measure the confidence of the directed edge. The strength indicates the frequency of the edge is present and the direction measures the frequency of the direction conditioned on the presence of edge. PSA: Projected shoot area; RB: root biomass; WU: water use; WUE: water use efficiency