Reduction of Seed-Borne Fungi of the Genus Aspergillus Associated with Egusi Melon Colocynthis citrullus (L.) Seeds Using Chlorine Disinfectants "“ Implications on Seed Germination

Abstract: A laboratory trial was conducted in 2014 at Michael OKPARA University of Agriculture, Umudike, Abia State of Nigeria to determine the effects of three chlorine disinfectants: potassium chloride, mercuric chloride and sodium hypochlorite on Aspergilus. niger, A. flavus, A. fumigatus and A. granulosis on seeds of Colocynthis citrullus (egusi melon). 400 seeds were pretreated with different disinfectant at different concentrations (0.1,1.0 and 2.0%) with distilled water as the control and at different time regimes (1, 3, 5 and 7 minutes). The surface sterilized seeds were cultured and incubated at 25±2⁰C for 7days. After which the seeds were examined for fungi growth and identification. Data obtained showed seed treatment with mercuric chloride was most effective in the reduction of A. flavus in C. citrullus seeds. Treatment of C. citrullus seeds with potassium chloride and sodium hypochlorite resulted in significant reduction in percentage recovery of A. flavus when compared with the control (distilled water). However, increase in concentrations of these two chloride disinfectants resulted reduction in percentage recovery of the pathogen but were more effective as surface disinfectants for C. citrullus seeds at low concentrations. From this study therefore to protect the seeds from surface infection and contamination by Aspergillus spp and other micro flora during storage and to maintain their viability status and also considering the toxic implications and environmental hazards of mercuric chloride, sodium hypochlorite becomes a preferred seed disinfectant chemical.