The determination of allelopathic effect of garden radish (Raphanus sativus L.) and little radish (Raphanus sativus L. var. radicula) on some annual and perennial weeds

In this study, extracts obtained using liquid nitrogen from garden radish (Raphanus sativus L.) and little radish (Raphanus sativus L. var. radicula) plants was performed on three different weeds (Avena sterilis L., Echinochloa crus-galli (L.) P. Beauv. and Sorghum halepense (L.) Pers) to evaluate the allelopathic effects of germination and seedling development and to determine the allelopathic content of extracts obtained from different parts of radish species (root, stem and whole plant). In the extraction process, the plant parts of the radish varieties were frozen with the help of liquid nitrogen and then, crushed and powdered. Aqueous solutions prepared with certain doses of radish powders (0%, 1%, 2%, 4%, 8%, 16%) were applied to weed seeds. Seeds were kept in an incubator at 25 °C for 15 days. Experiments were run in six replicates for each concentration. At the end of the application, the germination percentage of weed seeds was evaluated by measuring root and stem length. It has been demonstrated that all extracts adversely affect weed germination and seedling growth due to dose increase. Among the test parameters, the highest allelopathic effects were obtained from the root elongation of weeds. While the highest effects on A. sterilis were provided by garden radish root extract, it was found that E. crus-galli and S. halepense plants were mostly affected by little radish stem and whole plant (root+stem) extracts. As a result of the chemical analysis, potential substances that could be the source of the allelopathic effect were determined in the extracts. The plants selected and the extraction method used in the study were found to shed light on future allelopathic studies and bioherbicide researches.