Ipomoea batatas (L.) Lam. extracts and their allelopathic effect on weeds

Ipomoea batatas (L.) Lam. and their effect on weeds

Abstract

Many secondary metabolites that are synthesized in plants have allelopathic effects. Such allelochemicals are excreted by different routes and come to stimulate, delay or inhibit events such as germination, growth or development of other neighboring plants, an allelopathic phenomenon that has received special attention in recent years in agroecology due to its evident herbicidal properties. Some studies have allowed the development of new bioherbicides for control of weeds, replacing synthetic herbicides. The objective of these trials was to evaluate the allelopathic effect of aqueous and ethanolic extracts of Ipomoea batatas at different concentrations (0, 1, 2 and 3.33 %) on acceptor plants as: Amaranthus hypochondriacus and Portulaca olecarea under controlled conditions, taking as response variables total germination (GT), germination speed index (IVG) and root length (LR). The results showed that aqueous extracts at pH 7, had no effect on the germination of A. hypochondriacus, observing a slight delay in the speed of germination and a stimulating effect on root length at concentrations of 2 and 3.3 %. When the aqueous extract at pH 5 was tested, a significant inhibitory effect was evidenced in the three response variables, which increased with the concentration on the acceptors, being P. oleracea more sensitive. A similar result was obtained with the ethanolic extract, where the inhibitory effect was dependent on the concentration and A. hypochindriacus the most sensitive species until reaching 100 % germination inhibition even with the lowest dose.