Occurrence and Diversity of Seed‐Borne Fungi Associated With Stored Common Bean ( Phaseolus vulgaris L.) Varieties in West Hararghe Zone, Ethiopia

Common bean ( Phaseolus vulgaris L.) production is a vital component of agriculture and food security in the West Hararghe Zone. Nevertheless, postharvest losses caused by seed‐borne fungal pathogens are a major obstacle to productivity. This study aimed to identify the mycoflora associated with stored common bean varieties and to evaluate their effects on seed germination. Using purposive sampling, 45 samples of three common bean cultivars (Nasir, Awash‐1, and Awash‐2) were collected from three key districts (Anchar, Guba Koricha, and Chiro). The isolation and identification of seed borne fungi associated with common bean seed were done by using direct plating technique. The Nasir variety from Guba Koricha exhibited the highest mean moisture level (13.56%), while the minimum mean (9.20%) was identified in the Awash‐1 variety from the Chiro district. Fungal isolation and identification were conducted using the standard agar plate method, while pathogenicity was assessed through seed inoculation and germination assays. Out of 2250 plated seeds, 1267 were infected, resulting in an average infection rate of 56.3% (ranging from 40% to 88%). A total of nine fungal genera was isolated and identified into 15 fungal species. Fusarium was the most dominant genus by isolate count (385), followed by Aspergillus (346), Alternaria (164), Penicillium (86), Macrophomina (85), and Rhizoctonia (77). However, Alternaria alternata showed the highest frequency of occurrence, appearing in 86.7% of the seed samples, followed by Fusarium spp. at 75.6%. Among the studied districts, Guba Koricha exhibited the highest level of fungal infection, particularly in the Nasir variety, which reached an infection rate of 77.6%. Analysis of variance (ANOVA) confirmed that four pathogenic isolates ( Macrophomina phaseolina , Rhizoctonia solani , Fusarium oxysporum , and Alternaria alternata ) successfully induced root rot symptoms. Among these, Rhizoctonia spp. demonstrated the highest virulence, resulting in significantly greater disease incidence (DI) of up to 95% ( p ≤ 0.05), compared to only 0%–40% in the control groups. Furthermore, all inoculated treatments exhibited higher percent severity index (PSI) values than the uninoculated controls. The study concludes that a diverse array of seed‐borne fungi, dominated by Fusarium , Aspergillus , and Alternaria , are strongly associated with stored common bean seeds in selected districts of the West Hararghe Zone. This contamination adversely affects both seed viability and seedling health. These findings underscore the urgent need for improved seed storage practices and the development of effective, location‐specific disease management strategies. Future studies should incorporate molecular tools for species identification to confirm taxonomic accuracy and assess the genetic diversity of key fungal pathogens in stored seeds, thereby safeguarding crop quality.