Romanian Biotechnological Letters, cilt.21, sa.1, ss.11149-11159, 2016 (SCI-Expanded)
Allelopathic effect of essential oils found in Origanum onites L. (Ori) (Turkish oregano) and Rosmarinus officinalis L. (Ros) (Rosemary) was tested on five bread wheat cultivars and two weed species. The essential oils were applied at rate of 0, 2, 4, 8 and 16 μL/petri dishes to study their effect on seed germination and seedling growth of wheat cultivars and two weed species; AVEST (Avena sterilis) and SINAR (Sinapis arvensis) commonly found in wheat field. Both essential oils of Ori and Ros caused a generally detrimental effect on seed germination rate, seedling shoot length, seedling root length and seedling fresh weight of wheat cultivars. Ori and Ros oils caused 37 to 87% and 10 to 78% germination inhibition on wheat cultivars, respectively. Mean germination time was extended as the concentration of essential oil was increased. For majority of the traits tested in this study, there was significant interaction between essential oil type and wheat cultivars. Both essential oils suppressed germination rate of the tested weeds. Ori caused 97 to 100 % germination inhibition rate on SINAR, and 26.7 to 84.5 % in AVEST. Ros also caused 85 to % 100 germination reductions on SINAR. Wheat cultivars were less affected compared to weed species suggesting that proper doses of these essential oils could be used as a bio herbicide for weed control. The result of the study demonstrated that essential oils of Ori and Ros have allelopathic potential, presenting a risk or advantage to seed germination and seedling growth of winter and alternative wheat cultivars grown in Turkey.