Allelopathic interference of chickweed, Stellaria media with seedling growth of wheat (Triticum aestivum)

The question whether or not annual weeds are allelopathic under field conditions is important in assessing the interference potential of annual weed species. Research was conducted to investigate the probable involvement of allelopathy in the interference potential of chickweed, Stellaria media, a polycarpic winter annual weed. Chickweed maintains heterogeneous populations represented by different age-classes under natural conditions. Results indicate that both young and mature growth stages of chickweed contribute water-soluble phenolics to the soil. Soil amended with matured chickweed had a higher phenolic content than weed-infested soils. Both weed-infested and weed-amended soil affect the seedling growth of wheat. Chickweed could be allelopathic also to a crop of the current season under natural conditions, as it contributes water-soluble compounds to its associated soil.Key words: allelopathy, competition, chickweed, phenolics, weed, wheat.