Preheat oven to 350 degrees F (175 degrees C). Heavily grease and flour two 9x5 inch loaf pans.
Sift together flour, baking soda, and salt. Set aside.
In a large bowl, cream butter or margarine, and sugar until light and fluffy. Beat in eggs, one at a time.
Mix lemon juice and yogurt together and add alternately with the sifted flour mixture to the butter mixture. Mix until just blended. Stir in lemon rind and poppy seeds. Pour mixture into prepared pans and smooth tops.
Bake at 350 degrees F (175 degrees C) for 50 minutes or until browned and a knife inserted in the center comes out clean. Cool on rack for 15 minutes before turning out of pans.