Abstract
The wheat (Triticum aestivum, L. poaceae) and the weeds of both broad leaf and narrow leaf. The broad leaf as Lepidium sativum, coronopus squamatus, Ammi majus, Rumex dentatus, Beta vulgaris, Silybum marianum and Malva parviflora and the narrow leaf as Phalaris minor and Avena fatua common in the Egyptian fields were studied under laboratory conditions to evaluate the effect of aqueous extract concentrations of sorghum shoot and root on the weeds as a bio control. The used extracts of sorghum shoot and root acquired an effective role on the germination and growth criteria of wheat and deleterious effect on germination of weeds. The results revealed that the used sorghum shoot extracts reduced the germination percentage of wheat while the root extracts except 90 and 100% concentrations of the plant induced wheat germination percentages. Most weeds germination percentages were reduced by both sorghum shoot and root extracts and even some extracts led to no germination of the weeds seed. The germination percentage of the most dangerous wheat weed (Avena fatua) was reduced remarkably due to all extract concentrations of sorghum shoot and root. Most sorghum shoot and root extracts increased wheat shoot and root lengths and dry weights. The effect was more by sorghum root extracts than by shoot ones. Inhibition in germination of weeds could be due to the allelochemicals as phenolics, flavonoids and saponins released from sorghum shoot and root which suggesting using the plant as an efficient herbicide.