Heat waffle iron. Drain and dice apricots; reserve 1/2 cup syrup, set both aside. Combine yogurt and reserved syrup; set aside for topping.
Combine whole wheat flour, all-purpose flour, baking soda, baking powder and 1 tablespoon sugar; set aside.
Whisk together buttermilk, egg yolk, vanilla, and oil. Stir into dry ingredients until just moistened. Fold in apricots and pecans.
Beat egg whites until soft peaks form; add remaining 2 tablespoons sugar and continue beating until firm peaks form and egg whites are shiny. Stir 1/4 of egg whites into waffle batter. Fold in remaining egg whites. Measure 2/3 cup batter for each waffle.
Cook about 4 minutes. Serve with reserved yogurt topping.