Preheat the oven to 350 degrees F. Spray a 9-by-5-inch loaf pan with cooking spray. Line the pan with overhanging parchment and spray the parchment.
Mash the banana in a medium bowl with a fork. Add the sugar, butter, yogurt, orange juice, vanilla and egg and whisk.
Mix together the baking soda, salt and 1 1/2 cups of the flour in a bowl. Fold the dry mixture into the banana mixture with a spatula. Toss the peaches and blueberries with the remaining 2 tablespoons flour and fold into the batter. Pour the batter into the prepared pan.
Bake until a toothpick inserted in the center comes out clean, about 50 minutes. Let cool in the pan for 10 minutes, then use the overhanging parchment to transfer the loaf to a rack to cool completely.