ALLELOPATHIC ACTIVITY OF SOME SELECTED MEDICINAL PLANTS ON BARNYARD GRASS (Echinochloa crus-galli (L.) P.Beauv.) AND OKRA (Abelmoschus esculentus)

Abstract

Medicinal plants enriched with many types of chemicals secondary metabolites which also act as allelochamicals. An experiment was conducted to evaluate the effect of allelochamicals of five medicinal plant species i.e. Asparagus (Asparagus racemosus wild.), Lebbeck (Albizia lebbeck), Devil's cotton (Abroma augusta), Scarlet gourd (Coccinea cordifolia), Spreading hogweed (Boerhavia diffuse linn.) on phytotoxicity regarding root and shoot growth of two test species (okra and barnyard grass). Five concentrations of each medicinal plant extract viz. T 0 (control; no extract), T 1 v

(0.01 mg dry wt. eq. extract/mL), T 2

(0.03 mg dry wt. eq. extract/mL), T 3 (0.1 mg dry wt. eq. extract/mL) and T 4 (0.3 mg dry wt. eq. extract/mL) were used for allelopathic test. The experiment was laid out in Completely Randomized Design (CRD) with three replications. Results showed that all the test species were found sensitive under extracts of all five medicinal plants. Results indicated that all concentrations of plant extract showed allelopathic effect on okra and barnyard grass. Among all concentration of plant extract, T 4 (0.3 mg dry wt. eq. extract/mL) showed highest allelopathic effect on both okra and barnyard grass seeds. In terms of root length of okra seeds, Spreading hogweed and Scarlet gourd extract at T 4 (0.3 mg dry wt. eq. extract/mL) showed highest allelopathic effect and gave lowest root length (0.533 mm). The Spreading hogweed (Boerhavia diffuse linn.) extract at T 4 (0.3 mg dry wt. eq. extract/mL) concentration on barnyard grass seeds showed highest phytotoxic effect for shoot and root length (1.9 mm and 0.93 mm, respectively). The above results suggested that those Scarlet gourd and Spreading hogweed may have allelochemicals and could be used as bioherbicide for successful crop production.