Mix together thoroughly the sugars, vegetable oil, and egg.
In a separate bowl, sift together flour, baking soda, and salt. In another bowl, combine sour cream and vanilla. Alternately add dry ingredients and sour cream mixture to sugar mixture
Blend in rhubarb and pecans.
Pour into 1 regular and 1 small, greased and floured bread pans. Or may be baked in a greased and floured bundt pan.
Prepare topping by combining 1/2 cup brown sugar, 1/2 teaspoon cinnamon, and 1-2 tablespoons butter into fine crumbs. Sprinkle onto bread mixture already in the pans.
Bake 350 degrees F.for 55-60 minutes. Cool 10 minutes before removing from pans. Best if served warm.