Chukwudi, Christopher UbaziAbdulkarim, Bello MuhammadJosiah, Chukwudi OnovoRacheal, Ozofu EwuleShatu, Wudiri AsalaPeter, Napoleon Idachaba2023-12-142023-12-142020-02-28[1] Ferguson, J.J. and Rathinasabapathi, B. (2003) Allelopathy: How Plants Suppress Other Plants. http://edis.ifas.ufl.edu [2] Ashrafi, Z.Y., Sadeghi, S., Mashhadi, H.R. and Hassan, M.A. (2008) Allelopathic Ef- fects of Sunflower (Helianthus annus) on Germination and Growth of Wild Barley (Hordeum spontaneum). Journal of Agricultural Technology, 4, 219-229. [3] Gilani, S.A., Kikuchi, A., Shinwari, Z.K., Khattak, Z.I. and Watanabe, K.N. (2000) Phytochemical, Pharmacological and Ethnobotanical Studies of Rhazyastricta Decne. Phytotherapy Research, 21, 301-307. https://doi.org/10.1002/ptr.2064 [4] Nazir, T., Uniyal, A.K. and Todria, N.P. (2007) Allelopathic Behaviour of three Me- dicinal Plant Species on Traditional Agricultural Crops of Garhwal Himalaya, India. Agroforestry Systems, 69, 183-187. https://doi.org/10.1007/s10457-006-9023-8 [5] IAS-Internation Allelopathy Society (2010) Constitution and Bylaws. http://www.ias.uca.es/bylaws.htm#sectionhttps://keffi.nsuk.edu.ng/handle/20.500.14448/6104A laboratory study was carried out to evaluate the effect of leaf aqueous ex- tract of Jatropha curcas L. on germination and early shoot growth of four pepper (Capsicum) species at the Department of Plant Science and Biotech- nology Laboratory, Nasarawa State University, Keffi, Nigeria. Data collected were percentage inhibition and shoot length. Results from the experiment in- dicated that there was significant difference between the treatments (4%, 8%, 12%, 16% and 20%) and the control (0%) and within the treatments at P ≤ 0.05. All the test crops were affected by different concentrations of the aque- ous extracts and the most pronounced effect was at 12%, 16% and 20% con- centrations of the extracts in all cases respectively. Germination, shooting were inhibited completely at higher concentrations in the cases when com- pared with the control. The inhibitory effect was found to be concentration dependent and may be due to the presence of water soluble allelochemicals like phenols, tannins and azeliac acid.enatropha curcas, Capsicum, Aqueous, Allelochemicals, Phenols, AzeliacArticle