Does the Interference of GR® Volunteer Corn Alters Stress Metabolism on Soybean?

C Piasecki,G Chavarria,A Caverzan,J Schons,M.A Rizzardi

doi:10.1590/s0100-83582018360100018

Abstract

ABSTRACT: The cultivation of GR® corn prior to soybean favors the occurrence of GR® volunteer corn plants interfering in soybean crops. The interference of volunteer corn causes the soybean yield losses, and the magnitude of losses varies with the corn density. The soybean yield losses can be partially explained by the occurrence of oxidative stress, which occurs by the higher content of reactive oxygen species (ROS), such as hydrogen peroxide (H2O2). The objective of this study was to quantify H2O2 content and the activity of superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) on soybean as a function of interference of populations of GR® volunteer corn originated from individual plants and clumps (clumps are seven corn plants emerged at the same point) in different times, as well as to determine wheter this interference alters stress metabolism on soybean. Quantification was performed at 20, 35 and 46 days after emergence (DAE) of soybean. The mean volunteer corn populations were 0, 0.5, 1, 2, 4, 8, 10 and 12 plants or clumps m-2. The results show changes in H2O2 content and SOD, CAT and APX activity as a response to interference with volunteer corn populations and origins. The higher activity was observated for SOD. Soybean yield reduce with the increase of populations of volunteer corn originated from individual plants and clumps.

Highlights

The cultivation of soybean after glyphosate-resistant (GR®) corn favors the occurrence of GR® volunteer corn (VC) plants, interfering with soybean (Marquardt et al, 2013)
The objective of this study was to quantify H2O2 content and the activity of the enzymes superoxide dismutase (SOD), CAT and ascorbate peroxidase (APX) in soybean in interference with populations of GR® VC originated from individual plants and clumps in different periods, as well as to determine whether this interference alters stress metabolism on soybean
In order to establish the interference/competition of soybean with the populations of GR® VC originated from individual plants or clumps, in the 2013/2014 season two experiments were carried out at the Centro de Pesquisa e Extensão Agropecuária (CEPAGRO) of the Universidade de Passo Fundo (UPF), Passo Fundo - Rio Grande do Sul, Brazil

Summary

Introduction

The cultivation of soybean after glyphosate-resistant (GR®) corn favors the occurrence of GR® volunteer corn (VC) plants, interfering with soybean (Marquardt et al, 2013). Referred to as “tigueras” or “plantas guachas”, VC originate from unharvested seeds or those lost during harvest. These seeds occur individually, producing individual plants, or as whole ears or rachis segments, resulting in clumps derived from several seeds present at a single point (Beckett and Stoller, 1988; Bernards et al, 2010). VC has a high competitive capacity in relation to soybean and reduce soybean yield even in populations less than one plant per square meter (Piasecki et al, 2015). Among the factors that affect the competition degree of the community infesting the culture, it is possible to highlight aspects related to weed species, distribution and population (Pitelli, 1985), period of coexistence and edaphoclimatic conditions (Silva et al, 2009)

Objectives

Methods

Results