Weed Biology and Management (2005) 5, 105-109

Harminder Pal Singh, Daizy Rani Batish, Jasvir Kaur Pandher and Ravinder Kumar Kohli (2005)
Phytotoxic effects of Parthenium hysterophorus residues on three Brassica species
Weed Biology and Management 5 (3), 105-109
Abstract: A study was conducted to assess the phytotoxicity of residues of Parthenium hysterophorus, an exotic invasive weed, towards the growth of three Brassica species (Brassica campestris, Brassica oleracea and Brassica rapa). The early growth of crops, measured in terms of seedling length and dry weight, was significantly reduced when grown in soil amended with varying amounts of Parthenium residues. A direct relationship was observed between the amount of residue incorporated in the soil and growth reduction. This adverse effect on Brassica crops indicates the presence of some growth-retardatory substances which are possibly released by the residues into the soil medium. In order to test this, aqueous extracts (1, 2, and 4%) of residues were prepared. It was observed that, in a laboratory bioassay, these extracts severely reduced the early growth of Brassica species, thereby indicating the presence of some water-soluble, inhibitory principles in Parthenium residues. A significant amount of the phenolics, the largest group of secondary metabolites usually implicated in allelopathy, was estimated in residue extracts, as well as in residue-incorporated soil. The phenolic content increased with increasing residue concentration, thereby showing their direct involvement in the observed growth inhibitions. Therefore, the study establishes that Parthenium residues exert an allelopathic influence on the early growth of Brassica crops by releasing water-soluble phenolics into the soil.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Harminder P. Singh, Daizy R. Batish

Research topic(s) for pests/diseases/weeds:
general biology - morphology - evolution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Parthenium hysterophorus (weed)