Effects of L. Extract and Allelochemical Eugenol on Rice and Associated Weeds Germination and Seedling Growth.

Natural herbicide is considered as a sustainable approach for weed management in agriculture. Here, allelopathic activities of L. extract (BE) and known allelochemical eugenol (EU) were studied against rice and associated weeds in terms of germination and seedling growth. Five plant species including a rice crop ( L.); a dicot weed, false daisy ( (L.) L.); and three monocot weeds, barnyard grass ( (L.) P. Beauv.), swollen fingergrass ( Sw.), and weedy rice ( f. Roshev.) were studied. The paper-based results demonstrated that BE and EU had inhibitory effects on seed germination and seedling growth. The IC values of BE and EU for seed germination were ranked from swollen fingergrass, to false daisy, barnyard grass, rice, and weedy rice, respectively. The ratio of root to shoot length of the seedlings indicated that the roots were more affected by the treatments than the shoots. In addition, the gel-based results showed the reduction of the rice seedling root system, especially on lateral root length and the numbers upon the treatments. Taken together, BE had an allelopathic activity similar to that of EU. Interestingly, the major paddy weed, barnyard grass, was more sensitive to BE than rice, underlining BE as a natural herbicide in rice agriculture.