Allelopathic effect of sunflower (H. annuus L.) on the germination of two weed species

This work was carried out in Agricultural Sciences Faculty, Central University of Las Villas in order to evaluate in "in vitro" condition the germination in two species of weed (Portulaca oleraceae L. y Amaranthus dubius Mart.) present in the crops field. The evaluation consisted in the application of sunflower extracts upon these. Significant differences were obtained in the germination of both species of weeds. In P. oleraceae the dose lethal (DL50) was 25% and controlled more than 70% of the populations. In the case of A. dubius the inhibition began immediately after the seeds enter in contact with the sunflower extract.