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 IPROTM. 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.摘要：抗农达（Roundup Ready，RR）大豆是为配合草甘膦（glyphosate）开展杂草防控而研发的作物品种。目前已有部分含草甘膦的除草剂复配方案应用于杂草防控，但该施用方式可能会对RR大豆的农艺性状表现产生不利影响。本研究在巴西巴拉那州（Paraná）的帕洛蒂纳（Palotina）与马歇尔·坎迪多·龙东（Marechal Cândido Rondon）两个市镇开展两组田间试验，评估苗后施用除草剂与草甘膦复配方案对RR2大豆农艺性状的影响。 试验采用随机区组设计，共设置7个处理组、4次重复，每个试验点共计28个试验小区。两组试验均选用Monsoy 6210 Intact RR2 IPROTM品种进行种植。 试验测定的指标包括：施药后3、7、14、21及28天的药害等级（phytotoxicity），叶绿素a、叶绿素b及总叶绿素含量，植株最终株高，单株荚数，百粒重及籽粒产量。采用方差分析（analysis of variance）与5%显著水平下的图基（Tukey）检验对试验数据进行统计分析。结果表明，两处试验点的药害等级在不同处理组间均存在显著差异；帕洛蒂纳试验点的籽粒产量与马歇尔·坎迪多·龙东试验点的最终株高也存在显著的处理间差异。 基于试验数据可知，部分除草剂与草甘膦的复配组合——如乳氟禾草灵（lactofen）与乙氧嘧磺隆（chlorimuron-ethyl）——可增强药害效应，甚至导致籽粒产量下降。