1. Preheat the oven to 350 degrees.
2. Mix together the whole wheat flour, baking powder, baking soda, and salt.
3. Cream the butter, sugar, and orange rind until fluffy. Add the vanilla and eggs and beat well.
4. Add the dry ingredients and milk, and mix well. Fold in berries and spread in an oiled 13- by 9- by 2-inch baking pan.
5. Bake for 40 minutes, or until a toothpick inserted comes out clean. Cool in the pan on a wire rack.