In a large bowl, combine the first five ingredients. In another bowl, combine egg, orange juice, water, butter and orange zest. Add to dry ingredients just until combined. Fold in the blueberries. Pour into a greased and floured 8x4-in. loaf pan.
Bake at 350° for 65-70 minutes or until a toothpick inserted in the center comes out clean. Cool for 10 minutes; remove from pan to a wire rack.
If using frozen blueberries, use without thawing to avoid discoloring the batter.