EFFECTS OF LIPPIA MULTIFLORA LEAF EXTRACT AND ASPERGILLUS FLAVUS ON GERMINATION AND VIGOUR INDICES OF SORGHUM BICOLOR [L] (MOENCH)

Abstract

This study was therefore designed to identify seed-borne fungi of sorghum in Minna, Niger State, Nigeria and investigate the effects of Lippia leaf extracts on the germination of sorghum seeds treated with A. flavus mycelia and its metabolites. The prominent isolated fungi species were Rhizopus nigricans (23.53%), Aspergillus flavus (17.65%), A. niger (17.65%), Sporisorium sorghi (11.76%) and Neurospora sitophillus (5.88%). The A. flavus metabolites were extracted with dichloromethane and phosphoric acid (90:10 v/v). Powdered Lippia leaves were extracted with ethanol for 72 h. A set of ten sorghum seeds in three replicates were subjected to each treatment and left for 24 h before been set-up in the germination chamber. At 9 days after sowing (9 DAS), the seeds treated with combined A. flavus mycelia and their metabolites had the least germination percentage (30%), the highest rot-index (3.0) and the least germination vigor (0.99). The seeds applied with only Lippia leaf extract had the highest percentage germination of 100%, the zero rot-index and highest seedlings vigour index (5.4). Though Lippia leaf extract application on seeds reduced adverse effect of A. flavus and its metabolites on sorghum germination and promotes vigor indices, further investigation on their field trial and formulation into botanical fungicide are imperative.