Baseline Sensitivity of Echinochloa crus-gall and E. oryzicola to Florpyrauxifen-Benzyl, a New Synthetic Auxin Herbicide, in Korea

Soo-Hyun Lim; Harim Kim; Tae-Kyeong Noh; Ji-Soo Lim; Min-Jung Yook; Jin-Won Kim; Jee-Hwan Yi; Do-Soon Kim

doi:10.3389/fpls.2021.656642

Baseline Sensitivity of Echinochloa crus-gall and E. oryzicola to Florpyrauxifen-Benzyl, a New Synthetic Auxin Herbicide, in Korea

Front Plant Sci. 2021 Jun 9:12:656642. doi: 10.3389/fpls.2021.656642. eCollection 2021.

Authors

Soo-Hyun Lim¹, Harim Kim¹, Tae-Kyeong Noh¹, Ji-Soo Lim¹, Min-Jung Yook¹, Jin-Won Kim², Jee-Hwan Yi³, Do-Soon Kim¹

Affiliations

¹ Department of Plant Science, Department of Agriculture, Forestry and Bioresources, Research Institute of Agriculture and Life Sciences, College of Agriculture and Life Sciences, Seoul National University, Seoul, South Korea.
² Crop Protection Division, National Institute of Agricultural Sciences, Rural Development Administration, Jeonju, South Korea.
³ Integrated Field Science, Corteva Agriscience, Indianapolis, IN, United States.

Abstract

Echinochloa species is one of the most problematic weed species due to its high competitiveness and increasing herbicide resistance. Florpyrauxifen-benzyl, a new auxin herbicide, was recently introduced for Echinochloa management; however, the potential risk for the development of herbicide resistance in Echinochloa species has not been well-investigated. Thus, this study was conducted to evaluate the baseline sensitivity of Echinochloa species to florpyrauxifen-benzyl to estimate the risk of future resistance development. A total of 70 and 71 accessions of Echinochloa crus-galli and Echinochloa oryzicola were collected from paddy fields in Korea, respectively. These two Echinochloa species were grown in plastic pots up to the 5-leaf stage, and treated with florpyrauxifen-benzyl at a range of doses from 2.2 g to 70.0 g a.i. ha^-1. Nonlinear regression analyses revealed that GR₅₀ values for E. oryzicola ranged from 4.54 g to 29.66 g a.i. ha^-1, giving a baseline sensitivity index (BSI) of 6.53, while those for E. crus-galli ranged from 6.15 g to 16.06 g a.i. ha^-1, giving a BSI of 2.61. Our findings suggest that E. oryzicola has a greater potential risk than E. crus-galli for the development of metabolism-based resistance to florpyrauxifen-benzyl.

Keywords: Echinochloa species; Rinskor; baseline sensitivity; florpyrauxifen-benzyl; herbicide resistance.