Plot of sugar conversion and particle size distribution and biplot of sugar yield and chemical changes during pretreatment. (A) Loadings along the first two principal components obtained in a principal component analysis model including total sugar (TS) conversions of unfractionated (Unfrac), coarse, medium and small fractions and particle-size distribution (PSD) of coarse, medium and small fractions as percentage of the total mass. Placing of straw cultivars is based on samples from both sites. (B) Scores (straw cultivars) and loadings along the first two principal components obtained in a partial least squares (PLS) regression analysis model of total sugar yield in unfractionated samples correlated with chemical composition (Cell = cellulose, Hemicell = hemicellulose) before and after pretreatment (pt) as a percentage of total mass and particle size distribution of coarse, medium and small fractions as a percentage of total mass. Cultivars marked with circles were grown at Holstebro, and cultivars marked with triangles were grown at Fynen.