Isolation and Enumeration of Fungi and Determination of Contributing Factors to Fungal Spoilage in Maize (Zea mays L.) Originated from Selected Woredas of Oromia, Ethiopia

Abstract

Maize (Zea mays L.) is one of the most important staple crops in developing countries and it is the most widely cultivated plants in East Africa. Fungal spoilage on maize resulted in grain deterioration and mycotoxin contamination. In Ethiopia, maize production is prone to losses due to mold contamination. The purpose of this study was to isolate and characterize mycoflora and determine the Contributing factors to fungal spoilage in Maize. A total of 72 maize samples were collected based on incremental sampling method from east and west shewa zones of Oromia, Ethiopia. Four top maize producing districts consisting of two rural kebeles and one town were selected and from each site 6 maize samples of 1 kg were collected. Samples were properly labled with sample history and the moisture content was measured upon collection. From each sample, 15 maize grains were taken randomely and disinfected with 70 % ethanol for 2 minute, rinsed with distilled water and triplicates of five grains were cultured in Potato Dextrose Agar (PDA) amended with 0.01% chloramphenicol for 57 days at 25 . Fungal colonies were purified by sub-cultured on PDA. Morphological and microscopic characterization of the isolates was done based on fungal identification manual. Statistical data was analyzed using SPSS version 20. From the total 1080 maize grains analyzed, 613 fungal isolates were recorded with 54.1% mean percent of infection.448 isolates belongs to the genus Fusarium followed by 52 Penicillium, 46 Muchor and Rhizopus, 33 Aspergillus and 34 others. Samples obtained from Dano district showed higher mean percent of fungal infection (68.15%) followed by Adami Tulu (60.37%), Bako Tibe (50%) and Arsi Negelle (37.78%). Maize stored in plastic bag showed higher fungal percent of infection (62.5%) followed by gotera (51.1%) and fertilizer bag (49.63%).The grain mean moisture content was 14.16% with 11.0% minimum and 17% maximum value. Moisture content and storage duration were negatively correlated with fungal prevalence and were found statistically insignificant (p>0.05). Grains collected from warehouse were more infected (58.88%) followed by store (55%), open market (54.28%) and household (52.78%). No significant difference was obtained between the use of fertilizer and compost with fungal infection. Storage duration and percent of fungal infection showed weak negative correlation with statistical insignificance where one month storage showed higher prevalence (63.7%). Overall, the prevalence of fungal infection in the study sites was higher. Awareness creation to farmers, and capacity building training to experts and agricultural extension workers about pre and postharvest handling, maize breed type and mycoflora association studies and use of holistic, cumulative integrated management, monitoring, and precautionary measures are recommended.