The cluster analysis of the sequence tags with unique hit and annotation. The color schema indicates the level of expression. A higher gene expression level is shown with the red color. The samples marked with S at the end are sensitive biotypes and the samples marked with R at the end are resistant biotypes. The short labels indicate the biotypes from different locations in the US, and the long labels indicate the F1 progenies of two different biotypes. For example, DE1XCA1 indicates the plants are from the F1 population of DE1 and CA1 crosses.