Identification of soil-borne fungi in wheat rotation fields and biocontrol potential of Clonostachys rosea

Fungal diseases represent a major constraint on global wheat production, necessitating the development of sustainable management strategies that integrate biological control agents. This study aimed to characterize the culturable fungal community in wheat rotation systems (wheat, barley, safflower, chickpea, lentil, and vetch) in Haymana (Ankara, Türkiye) and to evaluate the antagonistic potential of indigenous Clonostachys rosea isolates. A total of 19 fungal isolates were recovered from 25 soil samples and identified via ITS rDNA sequencing as C. rosea (6), Fusarium equiseti (6), Fusarium oxysporum (4), Fusarium redolens (1), Alternaria alternata (1), and Alternaria atra (1). To assess biocontrol efficacy, three representative C. rosea isolates were screened against the virulent pathogen Fusarium culmorum using dual-culture assays. All tested C. rosea isolates significantly inhibited the radial growth of F. culmorum. The highest inhibition rate was achieved by isolate CR11 (32.19%), followed by CR14 (26.82%) and CR15 (15.94%). These findings suggest that wheat ecosystems may host beneficial antagonists, such as C. rosea, which could contribute to the development of biologically based integrated disease management strategies.