Results of principal component analysis (A) and association network (B) show the relationships between the major barley phenotypic traits integrated into the GeneNetwork. The network was built using scores of the first four principal components (c1–c4) calculated by combining data from a single trait measured in different locations and years, or related (component) traits underlying a higher order trait (e.g. malt quality data). Concerning the latter, principal component scores for malting quality traits were calculated from combined alpha amylase, diastatic power, grain protein and malt extract trait values. Principal component node colouring; c1-black background, c2-grey, c3 and c4 – white). Double-lined links – positive correlations; Bold, thick links – negative. For clarity, the network was re-drawn using GeneNetwork's output.