Effect of post-emergence herbicides on stress indicators in quinoa

Abstract

The impact of herbicide application on the accumulation of secondary metabolites and photosynthesis as stress indicators in the quinoa (Chenopodium quinoa Willd.) crop is unknown. The objective of the present study was to evaluate the effect of two post-emergence herbicides on production, total polyphenol content, and chlorophyll fluorescence in quinoa. The experiments were conducted for two consecutive seasons using a completely randomized block design with seven treatments, including two herbicides and three commercial product rates, as well as a control without herbicide application. Production parameters, yield components, and stress indicators were evaluated. Yield was affected (P < 0.05) by herbicide application in some treatments; control and treatment with only one bentazon application varied from 1851.23 to 1235.03 kg ha-1 , respectively. Yield affected the number of grains per plant (P < 0.05); control and treatment with only one bentazon application decreased yield from 3984.60 to 2040.94 kg ha-1 , respectively. Total polyphenol content and percentage of germination in quinoa grains were not affected by stress caused by herbicide application (P > 0.05). The herbicide fomesafen did not affect the maximum quantum yield, while the herbicide bentazon had a significant effect (P < 0.05) during the application. Three sequential applications of bentazon and fomesafen in the absence of weeds were sufficient to achieve a yield that was equal (P > 0.05) to the control.

Yield and nutritional value of two carrot cultivars in response to Linuron pre and post-emergence and three planting systems

“…Polyphenols are secondary metabolites that are essential in plants because they perform functions in response to stress conditions (Merino et al, 2020). Whereas DPPH-free radical scavenging is an indicator of non-enzymatic antioxidant activity.…”

“…Reduced crop growth and yield can be influenced by a decline in photosynthesis (Ali and Honermeier, 2016); however, this stress can diminish the biomass production, alter the quantity of the secondary plant metabolites (Olivoto et al, 2016); and increase the polyphenol content of the tissues (De Abreu and Mazzafera, 2005). Although, Merino et al (2020) stated that the total polyphenol content did not change duo to the herbicide application regardless the effect on the quinoa yield.…”

Laboratory Safety Evaluation and Weed Control Potential of Pre- and Post-Emergence Herbicides for Quinoa

“…Jacobsen et al demonstrated that inter-row hoeing with a 50 cm distance can significantly reduce weeds in quinoa fields [3], but this traditional method is inefficient when dealing with large quinoa fields. Weeds such as grasses and broadleaf species are difficult to eradicate completely, and therefore affect the normal growth of quinoa [4]. Manual weeding is labor-intensive and costly, and it is often abandoned in the later stages, which then severely affect the yield and quality of the quinoa [5].…”

Impact of PRE- and POST herbicide on purple nut sedge (Cyperus rotundus L.) control and plasticulture tomato yields

“…POST herbicides are necessary for nut sedge control, nonetheless few herbicides can be safely used pre or post transplant in tomato cultivation (Manning and Fennimore, 2001;Boyd, 2016;Merino et al, 2020). For this reason, most farmers apply PRE transplanting herbicides such as metribuzin and (S)-metolachlor (Devkota et al, 2013), and POST transplanting herbicides such as halosulfuron (Haar et al, 2002) for nut sedge suppression (Freeman et al, 2016;Boyd and Dittmar, 2018).…”