Studies investigating the allelopathic effect of root, stem, leaf and fruit water extracts and infested soil of Euphorbia helioscopia L. on the seed germination and seedling growth of wheat, chickpea, and lentil were conducted in a completely randomized design with 4 replications. | Research Article Turk J Agric For 34 (2010) 75-81 © TÜBİTAK doi: Allelopathic potential of Euphorbia helioscopia L. against wheat (Triticum aestivum L.), chickpea (Cicer arietinum L.) and lentil (Lens culinaris Medic.) Asif TANVEER*, Aqeel REHMAN, Muhammad Mansoor JAVAID, Rana Nadeem ABBAS, Muhammad SIBTAIN, Azraf Ul Haq AHMAD, Muhammad Sahid IBIN-I-ZAMIR, K. M. CHAUDHARY, Ahsan AZIZ Department of Agronomy, University of Agriculture, Faisalabad, 38040. Ph. – PAKISTAN Received: Abstract: Studies investigating the allelopathic effect of root, stem, leaf, and fruit water extracts and infested soil of Euphorbia helioscopia L. on the seed germination and seedling growth of wheat, chickpea, and lentil were conducted in a completely randomized design with 4 replications. Water extracts of root, stem, leaf, and fruit were prepared by soaking dried plant parts of E. helioscopia in water (1:20 w/v) for a period of 24 h. Seedling emergence, seedling vigor index, and total dry weight of wheat, chickpea, and lentil seedlings were significantly reduced when these crops were grown in soil taken from an E. helioscopia infested field compared to soil collected from an area free of any vegetation. E. helioscopia infested soil also significantly decreased the root length of wheat and lentil, and shoot length of lentil compared to the control soil. Water extracts of various organs of E. helioscopia significantly decreased the seedling vigor index and growth of test crops. Leaf extract had a greater inhibitory effect than the other extracts. Water extracts from the root, stem, leaf, and fruit of E. helioscopia resulted in a reduction in the seed germination (chickpea and lentil only) and germination index but the leaf extract increased the mean germination time in all test crops. Key words: Allelopathy, chickpea Euphorbia helioscopia, germination/seedling growth, lentil, wheat Introduction Besides competing for moisture, nutrients, and light, weeds .