LAUSR

ABSTRACT: The recognized allelopathic activity of oats as a soil-cover plant induces the study of the potential of their germplasm. The objective of this study is to verify if there is genotype variability in the Avena spp. with regard to allelopathic activity. Extracts of A. strigosa ‘Agro Quaraí’, ‘Agro Esteio’, ‘Embrapa139’, ‘AF 12104’, ‘AF 12109’, ‘AF 12202’, ‘AF 12209’, A. sativa ‘UPFPS Farroupilha’ and ‘AF 1345 Ucraniana,’ were prepared in three concentrations w/v (5 g, 10 g, and 20 g of dry mass 100 mL-1). The experiment was conducted in a germination chamber for 15 days, with lettuce (Lactuca sativa L.) as the recipient plant. There was complete inhibition of germination under 20% w/v extracts and partial inhibition at 10% w/v. Only 5% w/v observed a difference between the genotypes, in which the highest efficiency was obtained from the extracts of white oats and black oats ‘AF 12104’ and ‘Agro Quaraí’, which reduced germination between 92% and 97%. When the concentration increased above 5% w/v the harmful effect on germination was significantly greater. Only in extracts at 5% w/v there was a higher genotypic effect on germination, with variation in the germination rate index, root, and hypocotyl stretching. The genotype that had the least allelopathic effect was AF 12202, with an inhibitory mean in the evaluated attributes of 35%. The other genotypes inhibited the attributes of germination and seedling growth between 66% and 86%. With regard to the variability in the Avenaspp., the allelopathic activity could be applied to obtain cultivars with greater weed suppressive power.