Allelopathic effect of aqueous extracts of weed species on germination and seedling growth of some crops

A laboratory experiment was conducted during 2000–01 to study the allelopathic effect of weed species such as Cyperus rotundus, Commelina benghalensis, Parthenium hysterophorus and Prosopis juliflora. The aqueous weed leaves extract were applied @ 0% (control), 5% and 10% on sorghum, wheat, greengram, soybean, sunflower and groundnut seeds. Commelina and Cyperus extracts recorded significantly lower seed germination (80.1 and 85.3%), seedling length (10.0 and 11.5 cm) and seedling vigour index (866 and 1022), respectively as compared to Parthenium hysterophorus (89.5%, 13.1 cm, 1186) and Prosopis juliflora (92.5%, 14.4 cm, 1319), respectively. The groundnut and wheat were more resistance to allelopathic effect of weed species.