Occurrence of Seed-Borne Fungi in Selected Sunflower (Helianthus annuus) Varieties in Abuja, Nigeria

Study Design: Experimental in the Laboratory. Place and Duration of Study: This study was conducted at the Crop and Environmental Protection Laboratory, University of Abuja, Abuja-Nigeria. Aim: Investigated the occurrence of seed-borne fungi in seeds of five sunflower varieties in Abuja, Nigeria. Methodology: Seed samples were inoculated in Sabouraud Dextrose Agar where four improved sunflower varieties (SAMSUN1-4) and one of local variety (SKYSCRAPER) were plated and incubated to isolate colonies at temperature of 28 o C with duration of 5-7 days. The morphological identification of fungal isolates was performed, and the percentage of their presence was determined. At 3 days after incubation (3DAI) there was prevalence of Fusarium oxysporum (54.4%), Aspergillus niger (33.2%), Aspergillus flavus (6.8%) and Penicillium chrysogenum (5.6%). The frequency of occurrence (PF) for each fungus species was calculated. Data collected were subjected to ANOVA and analysed using descriptive and inferential statistics. Result: It was shown that dominant fungal species identified at 3DAI were - Aspergillus flavus (6.8%), Aspergillus niger (33.2%), Fusarium oxysporum (54.4%) and Penicillium chrysogenum (5.6%). Notably, it is also worth noticing that A. niger showed a growth of 2.09% at 4DAI and 1.90% at 5DAI. F. oxysporum increased from 274 and 306, representing 50.37% and 49.04% of the total isolates respectively. Conclusion: The presence of pathogenic and mycotoxigenic fungal species in seeds of the sunflower varieties highlights the potential implications for both agriculture and human health. Sunflower contains a great quantity of A. alternata (aflatoxigenic fungi and A. flavus (mycotoxigenic fungi) seeds. These observations validate the fact that an improved seed treatment, seed storage and fungal surveillance are the aspects that can be deployed to increase agricultural productivity and food safety.