EFFECT OF PLANT-DENSITY, SOWING DATE AND FERTILIZATION ON THE SUNFLOWER AGRONOMIC CHARACTERISTICS .1. GRAIN-YIELD AND OIL AND YIELD COMPONENTS

With the objective of identifing possible interactions between plant d ensity, planting date and soil fertility regarding grain yield and com ponents, percentage and yield of oil, an experiment was conducted at E ldorado do Sul, RS, Brazil, during the 1988/89 growing season. Four pl anting densities (30.000, 45.000, 60.000 and 75.000 pl/ha) and two pla nting dates (July, 27 and September, 19) were tested with and without fertilizer application. In the first planting date, grain yield increa sed with the increase of plant density for 75,000 and 60,000 pl/ha res pectively, for treatments with and without fertilizer. For the second planting date, plant density response was obtained only with fertilize r. The percentage of oil increased as plant density also did only for the first planting date. Oil yield showed a similar response to that o f grain yield.