A study was made of the F1 generation. Dominance was clearly expressed in several of the characters which constitute the wide morphological differences between the parent species. These included habit of growth, color and pubescence of stems, pubescence of leaflets, shape of calyx and corolla lobes, color and shape of corollas, and size and taste of tubers. Hybrid vigor was very pronounced. A high degree of sterility was found in both [male] and [female] germ cells; which made an F2 impossible.