The alkaloids of Lupinus mutabilis Sweet. and its use in the weed control

Allelopathy is described as the positive or negative effect that one plant causes on the growing of another, which occurs through the release of chemical components to the environment. The ‘tarwi’, Lupinus mutabilis Sweet., is a native legume from the Andean region whose seeds have a high protein content, however, these have a bitter taste due to the presence of alkaloids, metabolites that have been reported as allelochemical components, whose uses in agriculture are being investigated. Laboratory experiments were conducted to determine the effect of 5 concentrations (0, 1.55, 3.10, 4.65 and 6.20 mg mL^–1) of aqueous extract of tarwi alkaloids on the germination and growth of in vitro seedlings of three species of weeds; Amaranthus dubius, Bidens pilosa and Medicago polymorpha, in which the germination percentage, radicle and hypocotyl lengths of the seedlings were evaluated. An inversely proportional relationship between the concentrations and lengths evaluated for all species was considered, having A. dubius germination and M. polymorpha seedling growth as the most affected. The most significant reduction in germination and plant growth occurred at concentrations above 4.65 mg mL^–1.