ATIVIDADE ALELOPÁTICA DE EXTRATO AQUOSO DE Crotalaria spectabilis SOBRE O TRIGO E TRAPOERABA

Abstract

Wheat (Triticum aestivum L.) is one of the oldest cereals consumed by man and is currently one of the most cultivated cereals in the world. Due to the great agricultural importance of this crop, it is essential to look for better ways of production while reducing costs. Crotalaria, because of its rapid growth, has been highly recommended for green manure, aiming to supply the nitrogen need of crops of economic importance. When used as green covering it can have allelopathic influence on invasive plants such as trapoeraba, which is considered invasive on many crops in many countries. In Brazil, it has been cited as a problem plant in citrus, coffee, soybeans and corn. Therefore, in this work, the allelopathic effect of aqueous extract of Crotalaria spectabilis on wheat germination and initial growth was evaluated, verifying germination percentage (% G), fresh and dry length and mass of seedlings. The experiments were conducted in the botanical laboratory of Unicesumar, Maringá-PR and the treatments consisted of different concentrations (0, 25, 50, 75 and 100%) of aqueous extract of crotalaria, with a completely randomized experimental design. Five repetitions were made, each consisting of 25 wheat seeds, distributed in gerboxes and kept in incubation chamber at 25ºC with 12 hours photoperiod, for seven days. Data were evaluated by analysis of variance and means between treatments compared by the Scott Knott test at 5% significance. The data highlighted that the aqueous extract of Crotalaria spectabilis did not significantly change germination, however it has increased seedling length and fresh and dry biomass. Regarding trapoeraba, there were significant reductions in seed germination and seedling length, however, significant increases in fresh and dry biomass were identified. Therefore, it can be concluded that Crotalaria spectabilis can be used as plant cover in wheat crop without significantly altering the initial crop development, besides negatively altering trapoeraba.