Field experiments were conducted at three North Dakota rainfed environmens to compare the agronomic performance of early maturing dwarf and semidwarf sunflower Heilanthus annuus L. hybrids with a conventional height and maturity hybrid. The study evaluated hybrid response to several plant populations. No differences in seed yierd were observed among hybrids, row spacings, or the hybrid x row spacing and hybrid x population interactions. Increasing plant population, within ttre limits tested in this study, decreased seed yield of all three hybrids. Achene oil 66 consantration was influenced by environments and hybrids. As row spacing decreased achene oil concentration increased. Achene oil concentration increased as plant poputation, within the limits of this study increased. Oil yield (kg ha-1) was heavily influenceo by seed yieid and to a lesser extent by achene oil concentration. Lodging increased when the tallest hybrid was sown at a wide row spacing and high population. In most instances the performance of all three plant types was similar despite major differences in phenological development and plant stature.