Senecio filaginoides DC as a Source of Allelopathic Agents and Its Possible Use as a Bioherbicide

In this work, we experimented with aqueous and ethanolic extracts obtained from the aerial parts of Senecio filaginoides DC to evaluate allelopathic interactions in vitro with possible application as bioherbicides. S. filaginoides aerial parts were collected in Comodoro Rivadavia city (province of Chubut, Argentina) in May 2017. A voucher specimen was authenticated and deposited in the Patagonia Regional Herbarium of Universidad Nacional de la Patagonia San Juan Bosco (UNPSJB) under the following herbarium number: HRP N°6159-6170, the coordinates are South Latitude 45°50'17", West Longitude 67°30' 49". Seeds of Solanum lycopersicum and Lolium multiflorum that were obtained in the commercial market were used. From the plant material of S. filaginoides, two extracts, aqueous and ethanolic, were obtained; dilutions were made at 2, 4, 10 and 20%. Common water was used as control. In vitro bioassays were carried out and it was observed: the germination time, the germination percentage, the root and the stem growth. The data obtained were statistically analyzed using an analysis of variance (ANOVA), compared by the Tukey test. It was observed that the aqueous extract did not present significant interaction with the species studied for the concentrations tested. The germination percentage showed an inhibition with the ethanolic extract for all the concentrations studied in L. multiflorum and from the 10% concentration for S. lycopersicum species. A similar behavior of these species were observed in root growth compared to the different doses tested. A significant interaction was observed in the study of stem growth, where the species S. lycopersicum shows a stimulus at a concentration of 2%. The other concentrations showed an inhibitory action for this species. Based on these results, the ethanolic extract of S. filaginoides could potentially be used as a safe and environmentally friendly herbicide to develop new weed management methods under organic farming systems.