Variation in the Breadmaking Quality and Rheological Properties of Wheat in Relation to Sulphur Nutrition under Field Conditions

Seven field experiments were conducted at four sites in England in the 1994/95 and 1995/96 cropping seasons to investigate the effects of S application on the breadmaking quality of the premium hard winter wheat variety Hereward. Two N levels (180 and 230 kg/ha) were combined with three S levels (0, 20 and 100 kg/ha) in all experiments. Loaf volume was increased significantly by S in four out of the seven experiments, whereas increasing the N rate significantly increased loaf volume in only one experiment. Responses of breadmaking quality to S were more common than responses in terms of grain yield. Sulphur application did not affect grain protein concentration directly, but tended to increase gel protein weight in flour and the proportion of polymeric proteins. The elastic modulus of gel protein and dough resistance were decreased consistently by S, whereas dough extensibility was increased by S. Correlation and regression analyses showed that grain protein concentration was a poor indicator of loaf volume, whereas grain S status (S concentration and N:S ratio) was more influential. These results indicate that there is a current need to apply S fertiliser to wheat in many areas of England in order to maintain breadmaking quality.