RATE OF NITROGEN AND SULFUR FERTILIZERS ON YIELD, YIELD COMPONENTS AND SEED QUALITY OF OILSEED RAPE (BRASSICA-NAPUS L)

Two experiments were carried out to investigate the influences of nitr ogen and sulphur fertilizers on the morphology, reproductive structure s and seed quality of new cultivars of oilseed rape (Brassica napus). Yield and yield component responses were not consistent between years and cultivars. For the crop sown in 1988, application of nitrogen at 2 40 kg/ha increased total dry matter production and combine seed yield. Seed yield increased mainly due to greater number of pods on the term inal raceme and heavier seed weight whereas number of seeds per pod wa s not affected. Sulphur fertilizer application did not significantly i ncrease plant dry matter production, number of seeds per pod oi indivi dual seed weight. Considerable variation occurred between cultivars an d years in seed glucosinolate concentrations with the application of n itrogen and sulphur fertilizers. Nitrogen top dressings caused signifi cant increases in seed glucosinolate concentration in the droughty yea r of 1989 but not in 1990. Similar significant increases also occurred with sulphur application in 1990. Seed protein content generally incr eased with increasing rate of nitrogen application, with concomitant d ecrease in oil content. Sulphur application did not influence oil and protein contents.