ASSESSMENT OF ALLELOPATHIC EFFETS OF COGONGRASS (IMPERATA CYLINDRICA L.) ON WHEAT, ONION AND SOME ASSOCIATED WEEDS

Document Type : Research articles.

Authors

Plant Protection Dept., Faculty of Agric., Fayoum University, Egypt

Abstract

Studying the influence of cogongrass (Imperata cylindrica L.)
extract on germination and seedling growth of some weeds and crops
indicated that the dicotyledonous weeds such as goosefoot and sowthistle
were the most affected by the aqueous extract of cogongrass (rhizome and
foliage) than the monocotyledonous crops, wheat and onion, based on
IC
50 values. Delay in germination was more pronounced in weeds than
crops. Dry weight of wheat and onion seedlings were not significantly
affected meanwhile the dry weight of goosefoot, fieldbind and sowthistle
seedlings were significant, by lower than control. Rhizome extract was
generally more effective than foliage extract. Allelochemicals in
cogongrass (rhizome and foliage) analyzed by liquid
chromatography/mass spectrometry (LC/MS) were identified as phenolic
compounds that included 3'-o-methyl-(-)-epicatechin-7-o-sulphate,
vanillic, ferulic and coumaric acids in rhizome extract, in addition to (-)-
epigallocatechin-3,5-digallate, caffeic and gallic in foliage extract.
Chlorogenic acid was the principal phenolic compound in both extracts.
These results suggest that cogongrass might have an inhibitory effect.
Considering that cogongrass is an allelopathic plant might suggest its use
as soil additive material for weed control and could also serve as natural
herbicide.


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