Associations Between Herbicides and Glyphosate in Agronomic Performance of RR2 Intact Soybean

Abstract

-The Roundup Ready (RR) soybean was developed for weed control with the use of glyphosate. Some herbicide combinations with glyphosate has been used in weed control and some effects of this practice may be undesirable in the agronomic performance of RR soybean. The present study evaluated the agronomic performance of RR2 intact soybean applied with associations between herbicides and glyphosate at post-emergence, in two experiments conducted in two municipalities in the state of Paraná, Palotina and Marechal Cândido Rondon. This experiment consisted of seven treatments in a randomized block design with four replications, totaling 28 plots for each municipality. The cultivar used in both experiments was Monsoy 6210 Intact RR2 IPRO TM . The variables analyzed were: phytotoxicity at 3, 7, 14, 21 and 28 days after application, chlorophyll A, B and total chlorophyll, final height, number of pods, 100 seed weight and yield. Data were analyzed by analysis of variance and Tukey's test at 5%. There were differences between treatments for phytotoxicity in both locations and differences in yield (Palotina) and final height (Marechal Cândido Rondon). From the data it is understood that some associations of certain herbicides such as lactofen, chlorimuron-ethyl in the glyphosate can potentiating effect cause phytotoxicity and even reduction in productivity.Keywords: Glycine max, susceptibility, selectivity, phytotoxicity. RESUMO -A soja Roundup Ready (RR) foi desenvolvida para controle de plantas daninhas com a utilização do herbicida glyphosate. Algumas associações de herbicidas com o glyphosate vêm sendo usadas no controle de plantas daninhas, e alguns efeitos dessa prática podem ser indesejados no desempenho agronômico da soja RR. O presente trabalho objetivou avaliar o desempenho agronômico da soja intacta RR2 submetida a associações de herbicidas com o glyphosate, em pós-emergência. Para isso, foram realizados dois experimentos em duas localidades (Palotina -PR e Marechal Cândido Rondon -PR). Esses experimentos contiveram sete tratamentos com delineamento em blocos ao acaso com quatro repetições. O cultivar utilizado em ambas as localidades foi o Monsoy

Seletividade de herbicidas pós-emergentes isolados ou associados a fertilizante foliar na cultura da soja

“…Similar results have been observed by PROCÓPIO et al (2007), who, at 13 DAA, have found that the addition of 100 g ha -1 of imazethapyr to glyphosate, at any dose tested, and the combination of 10.0 g ha -1 of chlorimuron-ethyl with 1,440 g ha -1 of glyphosate promoted the highest levels of injuries to RR ® soybean plants, with percentages higher than 30%; the authors have also verified a decrease in the intensity of symptoms caused by the application of herbicides at 25 DAA. Results found by CESCO et al (2018) corroborate our work, as the association of chlorimuron with glyphosate in the development of RR Intact soybean caused phytotoxicity levels of 36% at seven days DAA. The actions of ALS-inhibiting herbicides reduce the levels of the amino acids valine, leucine, and isoleucine, which are directly linked to the production of cell growth proteins (GAZOLA et al 2016).…”

Grain productive efficiency of soybean plants under lactofen application

“…This effect may be directly associated with energy reallocation from root growth towards recovery from the phytotoxicity induced by lactofen. Santos et al (22) found reduced development of soybean roots when subjected to high doses of glyphosate, indicating that interference or phytotoxicity can lead to decreased root development. As well as, besides phytotoxicity, soybean plants submitted to application of the lactofen plus glyphosate showed lower plant height (23).…”