Effects of applied sulfur on glucosinolate and oil concentrations in the seeds of rape (Brassica napus L.) and turnip rape (Brassica rapa L. var. silvestris (Lam.) Briggs)

Abstract

The effect of sulfur availability on glucosinolate concentration in seed meal of glasshouse grown Brassica nupus cv. Wesbrook and Brassica rapa cv. Runyip was studied. In addition, field trials were evaluated to determine the degree of variability of glucosinolate concentrations in the seed and of sulfur in the plants of rapeseed grown at a number of sites throughout New South Wales.Glucosinolate concentration in seeds grown in the glasshouse increased (P < 0.01) in both cultivars with increasing sulfur application, ranging from an average of 5 8mol at 4 8g g-1 to 55 8mol at 100 8g g-1 sulfur. Bunyip containcd significantly higher concentrations (Pt0-01) than Wesbrook. Increased rates of sulfur application resulted in increased (P < 0.01) seed oil concentrations (from 28.7 to 37.6%), yield (3.1-27.1 g) and 1000-grain weights (2.1-2.9 g). Field trials showed site (P < 0.01) and cultivar (P<0.01) variation in glucosinolate levels. However, sulfur did not appear to be an independently limiting factor in field-grown plants.