The extent and association of chickpea Fusarium wilt and root rot disease pressure with major biophysical factors in Ethiopia

Fusarium wilt and root rot complex are among the major challenges to chickpea production throughout Ethiopia. Previous studies have surveyed economically important chickpea diseases in Ethiopia, but were restricted to the major chickpea growing areas and thus were unable to provide a broad geographic view of disease pressure. In the present study, we focus on understanding the extent of wilt/root rot disease pressure and its correlation with local edaphic and agronomic factors. In 2015 and 2016, we conducted geo-referenced field surveys covering 51 districts representing 17 chickpea growing zones, revealing that diseases were widely distributed in all surveyed areas. Across all surveyed sites, Fusarium oxysporum f. sp. ciceris ( Foc ) was the predominant species encountered among fungi cultured from plant tissue, representing 69.4% of total isolates. The remaining 30.6% of isolates were other root rot pathogens including Rhizoctonia bataticola, Fusarium solani, Sclerotium rolfslii, Rhizoctonia solani and unidentified fungi. Fusarium wilt and root rot diseases incidence were significantly ( P < 0.05 ) associated with clay soils (vertisols), Desi type chickpea, early planting, flowering and plant maturity. The highest mean percent diseases incidence per m 2 (45.65%) was recorded in the Amhara region, West Gojam zone, where heavy clay soils (typical vertisols) predominate and chickpea production is regularly threatened by high diseases pressure. Taken together, the results of this survey highlight factors associated with chickpea wilt and root disease and in doing so provide a framework for integrated disease management, while also nominating agricultural environments where breeding strategies for disease resistance might have greatest impact.