Allelopathic Effects of Azardiracta indica and Vitellaria paradoxa on the Germination and Growth of Pepper (Capsicum annuum L.)

Abstract

This work was conducted to evaluate the allelopathic effects of Neem (Azadirachta indica) and Shea butter (Vitellaria paradoxa) on the germination and growth of pepper (Capsicum annuum L.) in the Northern Guinea Savannah agro-ecological zone of Nigeria. The experiment was laid out in a Randomized Complete Block Design (RCBD) with three (3) replicates. Data were collected on germination rate, plant height, stem diameter, number of leaves, number of branches, root length, above ground biomass, and below ground biomass, and analyzed using Analysis of Variance (ANOVA) using Duncan’s Multiple Range Test (DMRT) for mean separation at 5% probability to separate means. Results showed that A. indica caused stronger inhibition of pepper seed germination and growth parameters than V. paradoxa. Germination percentages under neem were reduced to 57.33% compared to 67.67% under shea butter, both lower than the control (100%). Neem also suppressed plant height, stem circumference, and biomass more than shea butter. Although statistical analysis revealed no significant differences (p≥0.05) among treatments, the inhibitory trend suggests that these trees can influence pepper growth. Findings align with recent research on allelopathy in sustainable agriculture. It was recommended that farmers consider the placement of these trees on farmlands to reduce potential productivity losses.