Potencial alelopático de frações do sorgo (sorghum bicolos (L.) Moench) sobre a corda-de-viola Ipomoea grandifolia (Dammer) A'Donell) E caruru-roxo (Amaranthus hybridus L.)

Abstract

As the food need increases, a constant agricultural production flow must be provide and doing so, the use of pesticides is necessary. Finding a different way that cause less damage to the ecosystem and people themselves may be reached by studies about the allelopathy effect at weeds. Therefore, this work aimed to evaluate the allelophatic action of hexane, dichloromethane, butanol and ethyl acetate fractions of sorghum (Sorghum bicolor (L.) Moench) over the initial growth of morning glory (Ipomoea grandifolia (Dammer) O'Donell) and slim amaranth (Amaranthus hybridus L.), which verified the percentage of germination, speed of germination, seedling length and the fresh and dry biomass. The experiments were conducted using the B.O.D. incubation chamber at 25 °C during seven and fourteen days for morning glory and slim amaranth respectively. The experimental design was completely randomized, with five replicates in Petri dishes. The data were evaluated by the variance analysis and the average between each treatments were compared by the Scott Knott test at 5% of significance. The results indicated that the dichloromethane and ethyl acetate fractions decreased the initial growth of morning glory and slim amaranth, mostly when compared with hexane and butanol.