Clustering of expression profiles of genes that show 2-fold or more change in expression in Norstar and their comparative profiles in other genotypes. The x-axis in each frame represents duration of cold treatment from 0 to 70 days. The y-axis in each frame represents median centered relative gene expression in log 2. Relative expression was calculated by determining the difference between the maximum and minimum level of expression in the time-series. Cluster ID is indicated by the number on the upper left corner of each frame. The number of genes in each cluster is indicated on the lower right corner of each frame.