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

Abstract

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.

Quality Characteristics of Wholemeal Flour and Bread from Durum Wheat (Triticum turgidum L subsp. durum Desf.) after Field Treatment with Plant Water Extracts

“…According to the literature, an FN > 300 indicates low α‐amylase activity, whereas values of approximately 200 to 250 are indicative of normal enzyme activity (Caglar and others ; Bulut and others ). Although variations in FN values were found as a consequence of some aspects of crop management such as fertilizer type, weeding management (Bulut and others ) or seeding rates (Caglar and others ), no difference was found in relation to the application of different herbicides (Manthey and others ). A reduction in the FN is common in ripe wheat grain in which preharvest sprouting occurs (Humphreys and Noll ), but according to recent studies (Mares and Mrva ), a significant production of late maturity α‐amylase (LMA) is frequently detected independent of sprouting in commercially grown wheat.…”

Wheat preharvest herbicide application, whole‐grain flour properties, yeast activity and the degradation of glyphosate in bread

“…Despite some differences seen depending on the wheat sample, the presence of 6–11 mg kg −1 of glyphosate in whole‐grain flour had minor effects on dough and bread properties, confirming results obtained by others with lower levels of glyphosate in bran‐free flours (Darwent et al ., ; Manthey et al ., ). Not reported previously, glyphosate application in the field did not change the level of fructans in wheat kernels.…”

“…Glyphosate residues in mature wheat would have little effects on the bread-making potential of white flour, including dough mixing tolerance and bread volume Manthey et al, 2004;Craven et al, 2007). However, whole-grain flour would be more contaminated than white flour because pesticides residues accumulate on the external portions of wheat kernels (Amvrazi, 2011).…”

The Effects of Preharvest Glyphosate With Ammonium Adjuvants on Grain Protein Content of Hard Red Spring Wheat

“…Literature is limited on the impact of preharvest glyphosate applied with AMS at different timings. Manthey et al (7) found that glyphosate applied alone at the hard dough stage at the rate of 0.75 lb acid equivalent/acre did not affect grain protein content but did increase gluten index two to eight units in HRSW. Preharvest glyphosate applied alone to HRSW with grain moisture below 25% did not alter grain protein content but did increase grain yield in some locations compared with the windrowed control (5).…”

“…Glyphosate − a broad-spectrum systemic herbicide used to control annual and perennial species of both grassy and broadleaf weeds − is registered as a harvest aid in wheat (6,7). Preharvest applications of glyphosate have been shown to effectively facilitate wheat dry-down through chemical desiccation and is considered more dependable and economical than the traditional method of windrowing (4,5,7).…”