Expression heat map of genes in the area of the powdery mildew resistance QTL. Genes are arranged in their linear order along the chromosome, and trees are divided into groups according to powdery mildew resistance phenotype. Each column of colored blocks represents gene expression readings from one individual tree. Data for all genes queried by the microarray lying between positions 28.7-30.9 Mb of chromosome 12 are shown. Green blocks indicate trees where the expression of a given gene was lower than the average for that gene across all 48 trees; red blocks indicate plants where the expression of a given gene was higher than the average for that gene across all 48 trees. Genes differentially expressed between the powdery mildew disease resistance phenotype groups are indicated by sequence ID numbers. Gene expression markers with segregation expression patterns that did not correlate with powdery mildew disease resistance are denoted by diamonds. Chr, chromosome.