Preheat oven to 350°F and spray a 9 x 5-inch loaf pan with nonstick spray.
For the bread, whisk together flour, sugar, baking powder, baking soda, and salt in a large bowl. Make a well in the center of the mixture. Combine mashed banana, yogurt, melted butter, egg, and vanilla in a medium bowl; add to flour mixture and fold in until almost combined. Fold in pecans.
Scrape batter into prepared pan and smooth with an offset spatula. Tap pan sharply to remove air bubbles, and sprinkle turbinado sugar over batter.
Bake for 50 to 52 minutes, until bread is golden and springs back to the touch (if desired, tent with foil after 30 minutes of baking time to prevent over-browning). Bread is done when a toothpick inserted in the center comes out clean or with a few crumbs attached. Cool in pan on a wire rack for 15 minutes; carefully remove bread from pan and cool completely.