Allelopathic Activities of Methanol Extract of Calotropis Procera on the Germination of Maize Seeds.

ABSTRACT
The rising levels of toxic residues from various herbicides and insecticides in agricultural products demand immediate attention. Calotropis procera leaves are commonly used as a natural insecticide across different crops at various growth stages. However, these natural insecticides can have both positive and negative effects on plant development. This study aimed to assess the qualitative phytochemical components and allelopathic effects of Calotropis procera leaf extract on maize seed germination and seedling growth using standard methods. Methanol extracts of C. procera leaves were tested at concentrations of 2.5%, 5.0%, and 10% over a 12-day period to evaluate their impact on maize seeds. Measurements of root and shoot growth, germination rates, and seedling vigor were taken on days 3, 6, 9, and 12. The Methanol extract was found to contain Calotoxin, Calactin, Caffeic Acid, Thioacetate, Alpha-Amyrin, Beta-Sitosterol, Stigmasterol, Isoquercitrin, Quercetin, Kaemferol, Rhamnetin, Luteolin, Lineolone, Voruscharin, Uscharin, Uscharidin, Azeleatin and Tyranton. Inhibition of plumule and radicle growth increased with higher concentrations, with the greatest inhibition observed at 10% concentration. Similarly, germination rates dropped with higher concentrations, with the control group achieving 100% germination, compared to 10% and 30% at 10% and 5% concentrations, respectively. Seedling vigor was also significantly lower at higher concentrations, with values of 52 and 84.6 for 10% and 5%, respectively, in contrast to 423 in the control group. These results indicate that high concentrations of C. procera extract (10% and 5%) suppress maize germination and seedling growth. Therefore, using high concentrations of C. procera extract as an insecticide should be avoided during maize germination.