In no-till cropping systems, oat represents one of the winter most important crops among those that are used to form cover crops. The presence of allelochemicals in its tissues point to the importance of understanding this phenomenon in the crop. By analyzing the straw of oat genotypes and its allelochemicals, it is possible to obtain a evaluation of its allelopathic potential. Results of this study show that oat genotypes maintain their allelopathic potential during the final period of the life cycle. Genotypes that present greater allelopathic effects during that period are UFRGS 6, UFRGS 9, UFRGS 10, and UPF 13. Genotypes that exhibit least allelopathic effects during the same period are UFRGS 12, UFRGS 17, UFRGS 884077, and UPF 12. The effects produced by allelochemical compounds (phenolic acids) are similar to those brought about by oat genotypes extracts, suggesting a cause and effect relationship between the allelopathic effect of these substances and the tested genotypes. The allelochemical compounds present greater inhibitory effects to weed species (Alexandergrass) than to crop species (soybean), which also coincide with results obtained by crop residues produced by oat genotypes.
Alelopatia; Avena fatua; Avena sativa; Avena strigosa; phenolic acids