Competitive Ability of Canola Hybrids Resistant and Susceptible to Herbicides

M.R Durigon,G Chavarria,J Cechin,L Vargas,F Mariani,A.S Camera

doi:10.1590/s0100-83582019370100133

Abstract

ABSTRACT: This work aimed to compare the competitive ability of canola hybrids susceptible (conventional) or resistant to triazine or imidazolinone group herbicides, with turnip. The experiments were conducted in greenhouse, in a completely randomized design, with four replicates. The hybrids Hyola 571CL (resistant to imidazolinone), Hyola 555TT (resistant to triazine), and Hyola 61 (conventional) were used. The treatments consisted of ratios (100:0; 75:25; 50:50; 25:75; 0:100%) of canola and turnip plants. The evaluation was performed 44 days after emergence, determining the leaf área (AF), dry matter of aerial part (MSPA), and stature (EST) of the plants. The competitiveness analysis was performed through diagrams and interpretation of the competitiveness indexes. For the canola hybrids, the competition occurred by the same mean resources. There was damage to the crop growth in competition with the turnip. The turnip was not benefited only when in competition with Hyola 571CL hybrid, for the EST variable, and with the conventional canola, for the variable AF. There was significance for the competitiveness indexes, demonstrating that turnip is more competitive then the crop. Greater AF, MSPA, and EST occurred for canola plants in the smallest proportions of turnip and, for turnip plants, in the largest proportions of canola. The ability to compete with turnip is similar among hybrids, with injury to the crop and benefit to the weed, when competing. Interspecific competition is more damaging to canola hybrids; and intraspecific competition is more damaging to turnip.

Highlights

The presence of weeds in canola (Brassica napus L. var. oleifera) constitutes a barrier to reach high yields, reducing the availability of water, light and nutrients for the crop. Because they belong to the same family as canola (Brassicaceae), turnip (Raphanus sativus L. var. oleiferus Metzg) and wild radish (R. raphanistrum L.) are considered difficult to control species, and there are no products with proven efficiency on such species and selectivity to the crop (Vargas et al, 2011)
The development of canola hybrids with resistance to herbicides is considered an advance for the crop, allowing the management of weeds of difficult control
The development of hybrids with herbicide resistance may be associated with an adaptive cost to plants, reducing their ability to compete with weeds

Summary

Introduction

The presence of weeds in canola (Brassica napus L. var. oleifera) constitutes a barrier to reach high yields, reducing the availability of water, light and nutrients for the crop. Oleifera) constitutes a barrier to reach high yields, reducing the availability of water, light and nutrients for the crop. Because they belong to the same family as canola (Brassicaceae), turnip The development of canola hybrids with resistance to herbicides is considered an advance for the crop, allowing the management of weeds of difficult control. The development of hybrids with herbicide resistance may be associated with an adaptive cost to plants, reducing their ability to compete with weeds. Regarding herbicide resistance of the imidazolinones group, the adaptive cost of mutations in the gene encoding the acetolactate synthase (ALS) enzyme, which is inhibited by the herbicide in susceptible plants, is generally not high, and such resistance is considered to be an advance in being cultivated plants (Tranel and Wright, 2002; Tranel and Horvath, 2009)

Objectives

Methods

Results