Seed Germination and Growth Characters of Cowpea (Vigna unguiculata (L) Walp) as Influenced by Allelopathic Effect of Leaf and Root Extract of Siam Weed


  • Kayode Isaac Oyewusi The Federal Polytechnic Ado-Ekiti, Ekiti State, Nigeria.
  • Folasade Florence Samuel The Federal Polytechnic Isan -Ekiti, Ekiti State, Nigeria.
  • Medinat Idowu Akeredolu The Federal Polytechnic Ado-Ekiti
  • Adebola Philomena Kayode The Federal Polytechnic Ado-Ekiti



Average percentage inhibition, cowpea varieties, Siam weed extract, bioactive constituent


The experiment focused on seed germination and growth characters of cowpea as influenced by bioactive constituents in Siam weed extract. Improved seeds of three cowpea varieties namely: IT97K-568-18, IT98K-503-1, and IT98K-419-4 were planted in the early rainy season in April 2018. 24 Plastic containers of 3 litre capacity were perforated at the bottom and filled with loamy soil. The experiment consisted of a 2 x 4 x 3 factorial combination arranged in a randomized complete block design (RCBD) with three replications to make a total of 72 plots. Seeds of cowpea were sown per bucket at the depth of 2cm per hole. The 2 x 4 x 3 factorial treatments consisted of two plant parts of aqueous extracts of Siam weed (Leaf and Root), four parts of the extract solution were diluted with water and made into 25%, 50%, and 75% concentrations of the aqueous extracts while distilled water was used as the control and three cowpea varieties respectively. 300ml of an equal volume of the extract (as obtained from the leaf and root of Siam weed) was applied with an equal volume of water which served as the control while watering was done twice daily in the morning and evening for 4 weeks. Growth indices measured were germination percentage, days to emergence, root length, leaf area, shoot length, several leaves and branches, and plant biomass while the average percentage inhibition (API) was determined. The result of the phytochemical screening proved that the leaf and root of the Siam weed contained bioactive constituents which affected the germination of cowpea seeds.  The leaf of the Siam weed had a significantly higher concentration of bioactive constituent and this significantly reduced the growth of cowpea. Average Percentage Inhibition was highest in the leaf extract at 75% concentration compared to other concentrations while the control had the least. IT98K- 503-1 performed better based on some of the measured growth parameters. Extract from the Leaf caused maximum inhibition (API = 15.48%), while extract obtained from the root was significantly lower at (13.55%).  It is therefore recommended that further studies be made to examine the effect of these extracts on the yield and productivity of cowpea. The extract of Siam weed could also be harnessed to control the weeds menace on the farms.  In addition, the extract could have a potential for use in the control of soil-borne diseases.


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How to Cite

Oyewusi, K. I., Samuel, F. F., Akeredolu, M. I., & Kayode, A. P. (2022). Seed Germination and Growth Characters of Cowpea (Vigna unguiculata (L) Walp) as Influenced by Allelopathic Effect of Leaf and Root Extract of Siam Weed. Journal for Agricultural Technology, 1(1), 1–10.