Studies on biology, ecology and control of Amaranthus retroflexus populations from Türkiye

Amaranthus retroflexus (L.) is one among the most common weeds that invade different cropping systems in Turkiye. This study investigated seed germination response of A. retroflexus to various environmental factors such as temperature, sodium chloride concentrations, light conditions, pH, osmotic stress and soil burial depth. Additionally, this research also investigated the potential of various post-emergence herbicides to control A. retroflexus. The germination test at the start of the experiments showed that seeds were non-dormant and viable, with 98% germination within three days. The highest germination percentage (98%) of A. retroflexus was achieved at a temperature of 25°C. Salinity exerted significantly negative effect on the germination and no seed germinated at 200 mM sodium chloride concentration. Similarly, osmotic potential also inhibited germination significantly and germination percentage was 18% or lower at -0.4 MPa or higher osmatic potential. Meanwhile, light had no significant effect on germination, and a soil depth of 0-4 cm was found as the most suitable for emergence of A. retroflexus. Among the post-emergence herbicides, clopyralid and 2,4-D proved the most effective to control A. retroflexus.