First Report of Multiple Resistance in Galium aparine to ALS-Inhibiting and Auxin Analog Herbicides in Kermanshah, Iran

ABSTRACT: Catchweed Bedstraw (Galium aparine) is a problematic weed, which has become increasingly difficult to control with herbicides in Iran. The aim of this study was to screen selected putative-resistant populations of G. aparine for resistance to auxinic herbicides 2,4-D+MCPA and ALS-inhibiting herbicides sulfosulfuron, tribenuron-methyl, mesosulfuron-methyl + iodosulfuron-methyl-sodium. Populations of G. aparine were collected from different wheat fields in the west of Kermanshah, where herbicide-use pattern is typical for Iran. Herbicide resistance to premixed herbicide 2,4-D+MCPA was confirmed in several populations. More populations of G. aparine showed cross-resistance to ALS-inhibiting herbicides examined in this research. Some populations were found to have developed multiple resistant to both auxinic and ALS herbicides. Generally, the level of resistance to ALS-inhibitor herbicides was higher than that of auxin analog herbicides.