Effect of preharvest applied herbicides on breadmaking quality of hard red spring wheat

Certain herbicides can be applied prior to harvest for weed control in wheat. Research was conducted to determine the effect of preharvest applications of glyphosate, paraquat and metsulfuron + 2, 4-D on grain, flour and the breadmaking quality of hard red spring wheat. Herbicides were applied at soft dough (SD),~ 500 g kg^-1 kernel moisture and hard dough (HD), 350 g kg^-1 kernel moisture stages of Parshall hard red spring wheat. Test weight was reduced 1.3 and 2.3 kg hl^-1, 1000 kernel weight was reduced 3.5 and 4.5 g, and large kernel content was reduced 230 and 280 g kg^ -1 by glyphosate and paraquat respectively when applied at SD. Metsulfuron + 2, 4-D did not affect physical grain quality. Glyphosate and paraquat applied at SD and HD increased gluten index two to eight units. Metsulfuron + 2, 4-D reduced the gluten index four units when applied at SD. Dough mixing stability was increased 1.7 min by glyphosate applied at SD or HD, and by paraquat applied at SD. Dough mixing time during bread making was 0.5 min longer with flour from wheat treated with glyphosate and was 0.4 min shorter with flour from wheat treated with Metsulfuron + 2, 4-D at SD. Loaf volume, symmetry and crumb score were not affected by herbicide treatments.