Investigating glyphosate resistance in Amaranthus palmeri biotypes from Turkey

Amaranthus palmeri is a troublesome weed which growing in importance worldwide. It causes serious competition many crops. A. was introduced into Turkey 4–5 years ago and appears to adapt different environmental conditions. Monoculture cropping systems repeated use of the same herbicides have led development herbicide resistance several active ingredients including glyphosate, USA South America. This study conducted investigate evolution glyphosate Turkey. Seeds 21 populations were collected Turkish citrus fields where control problems with reported. A potentially susceptible population from maize field (GS1 biotype). putatively resistant (GS) biotypes germinated transplanted large pots, then allowed grow separate greenhouse chambers obtain F2 generations. After carrying out preliminary test experiment exclude most populations, dose-response applied at 3–4 true leaf stage 0, 332.5, 665, 1330, 2660, 5320, 10,640 21,280 g a.i. ha−1. Plants harvested days after treatment dry weight determined. Glyphosate recommended rate (1330 a.i ha−1) controlled GS by more than 95% while controlling GR about 45%. Among those biotypes, GR1 GR2 confirmed an incipient glyphosate. The effect on shikimic acid accumulation Results showed that GS2 biotype accumulated 3.1 1.56 times demonstrates there lower alleged GS1. These findings demonstrate some increased tolerance reinforces need implement integrated management this invasive plant