Adjust oven rack to lower-middle position and heat oven to 400 degrees F.
Whisk all-purpose flours, wheat germ, sugar, salt, baking powder, baking soda, and seeds together in large bowl.
Combine buttermilk and 2 tbsp melted unsalted butter in 2-cup liquid measuring cup.
Add wet ingredients to dry ingredients and stir with rubber spatula until dough just comes together. Turn out dough onto lightly floured counter and knead until cohesive mass forms, about 8 turns.
Divide and pat dough into 2 rounds and transfer to a greased baking sheet. Using a sharp serrated knife, make a 1/2-inch deep cross about 5 inches long on top of the loaf.
Bake until skewer inserted in center comes out clean, 45 to 50 minutes.
Remove bread from oven and brush with remaining 1 tbsp melted butter. Transfer loaf to wire rack to cool.