Study of allelopathic effects of different weeds on germination and seedling Growth of wheat

Laboratory and greenhous studies were conducted to determine the allelopathic potential of six common weeds of Golestan pastures and fields on wheat seed germination and seedling growth. shoot extracts of italian cocklebur ¬(Xanthium strumarium L.)¬, Russian knapweed ¬(Acroptilon repens (L.) DC.), andhairy fleabane ¬(Conyza bonariensis (L.) Cronq.), reduced wheat seed germination by 42%, 47%, and 20% respectively, when companed to the check treatment. However, allelopathic effects of shoot extracts of the low concentration caused an increase in wheat root dry weight, but higher concentration reduced shoat dry weight significantly. Root extracts of hairy fleabane, Russian knapweed, and cocklebur at the lower concentration stimulated length and dry weight of wheat root, but at the higher concentration root length and dry weight were reduced significantly. The result of greenhouse experiment showed that the shoot residuces of each one of the three weeds of both lower and higher concentration reduced root length and shoot length and dry weight of wheat and this reduction was significant for the higher concentration. Among the three weed, Russian knapweed extract showed strong activity and can be a promising natural product to be used as a herbicide in future.