Molecular characterization of fusarium species associated with wilt complex in chickpea

Abstract:

Fusarium wilt remains one of the most damaging diseases of chickpea worldwide, yet the species composition of the wilt complex varies by region and is rarely confirmed by molecular tools in East Africa. This research collected 48 wilted chickpea plants from farmers' fields across eight woredas of East Hararghe Zone, Oromia Region, during the meher season of 2022-23. Fusarium isolates were recovered on potato dextrose agar, purified to single-spore cultures, and identified using morphological characters alongside ITS and TEF-1α gene sequencing. Of 36 confirmed Fusarium isolates, four species were identified: F. oxysporum f.sp. ciceri (58.3%), F. solani (18.7%), F. equiseti (11.4%), and F. proliferatum (7.8%), with 3.8% remaining unresolved. Pathogenicity tests on susceptible variety JG-62 showed that F. oxysporum f. sp. ciceri isolates caused 64-92% wilt severity within 30 days, while F. solani produced moderate root rot symptoms (38-61% severity). TEF-1α sequencing resolved species boundaries more clearly than ITS alone, separating F. equiseti from F. proliferatum where ITS showed overlapping clusters. These results map the Fusarium wilt complex of chickpea in the eastern highland region of Ethiopia for the first time and highlight the need for race-level identification to guide resistance breeding.