Principal component analysis of red clover proteome in response to cold acclimation and recurrent selection. Principal component analysis of proteome composition in crowns of red clover was based on two-dimensional difference gel electrophoresis (2D-DIGE). Analysis was performed with non-acclimated (NA) and cold-acclimated (CA) plants of the cultivar Christie (C) and the cultivar Endure (E) and populations TF3 and TF4 obtained after three and four cycles of recurrent selection in each initial genetic background (TF0). Variation in the proteome in relation to the cold acclimation, genetic background and recurrent selection is illustrated along the first two principal components (PC). Cumulative proportion of variations explained by PC1 and PC2 is indicated.