Effect of Storage Time on Occurrence of Aspergillus species in Groundnut (Arachis hypogaea L.) in Eastern Ethiopia

Abstract

Groundnut is an important cash crop for domestic markets as well as for foreign trade in several developing and developed countries. It is also one of the most valuable cash crops in eastern Ethiopia. However, its production is constrained by Aspergillus species, which cause quantitative losses and produce highly toxic and carcinogenic chemical substances known as aflatoxins.This study was conducted with the objective to identify Aspergillus species associated with groundnut seeds with different storage time. A total of 45 groundnut seed samples with different storage time were collected from Babile, Fedis and Gursum districts of Eastern Ethiopia for mycological analysis in the year 2014. In this research, A. flavus species found in association with groundnut seeds in storage was determined. About 15 to 89% of collected groundnut seed samples were infected with various moulds including Aspergillus flavus, Aspergillus niger, Aspergillus nomius, Aspergillus tamari, and other Aspergillus species. A. flavus and A. niger species were the most prevalent mycotoxigenic fungi in all time of storage. The highest occurrence of A. flavus and A. niger were in Gursum one year stored groundnut seed samples. From the detected Aspergillus species, A. niger and A. flavus were the most prevalent species of the genus in groundnut seed samples examined and they were isolated from 46 and 43 on non-surface sterilized samples respectively. Their relative dominancy in number of isolates from the total fungi was 21.67% and 20.85% respectively. This research pointed out that storage time has effects in aflatoxigenic fungi contamination of groundnut seeds. Therefore, the current results suggest the urgent need to apply control measures against aflatoxigenic fungi and associated mycotoxins.