Fig. 2

A KN representing knowledge triples found in the training set of 34 articles, abstracts only. Yellow nodes refer to a trait entity, red nodes refer to gene/protein entities, and green nodes represent the metabolite entities. The centroid of this network is tuber flesh color. Nodes with bold outlines indicate that these entities have an experimentally proved association with tuber flesh color (trait of interest). This experimental evidence of these entities with tuber flesh color is reported in the articles [6, 7]. The color of edges reflects the document frequency (weight) of a relationship. Grey edges appear only in one document, whereas black edges appear in more than one. The nodes are organized in circles around the trait of interest. The nodes in the innermost circle (circle 1) are 1st order neighbours of the flesh color node; the nodes in circle 2 are 2nd order neighbours of it; the nodes in circle 3 (the outermost one) are 3rd (or higher) order neighbours of the flesh color node, or not connected to it at all