Variation within flax (Linum usitatissimum) and barley (Hordeum vulgare) in response to allelopathic chemicals.

A possible method of manipulating allelopathy would be to develop crop varieties showing an increased tolerance to allelopathic chemicals. We therefore examined four flax (Linum usitatissimum) varieties and two wild Linum species in the presence of p-coumaric acid and four barley (Hordeum vulgare) varieties in the presence of p-coumaric acid, scopoletin and wild oat (Avena fatua) extract. Analysis of variance indicates significant interaction between variety and treatment for shoot and root growth for seedling flax, shoot growth for older flax, and root growth for seedling barley. These differences in tolerance between varieties could be exploited to develop-varieties with greater tolerances to the allelochemicals produced by weeds or in crop residues and therefore potentially more tolerant of the presence of weeds.