Identification of Fusarium spp. Associated with Chickpea Root Rot in Montana

Root rot caused by Fusarium spp. is a significant issue in the chickpea-growing regions of Montana. The specific Fusarium species responsible for the disease and their prevalence remain uncertain. A survey was conducted in 2020 and 2021 to identify Montana’s Fusarium species associated with chickpea. Four hundred and twenty-six Fusarium isolates were recovered from symptomatic chickpea roots across ten counties in the state. Isolates were identified by comparing translation elongation factor 1-α (TEF1-α) sequences in the FUSARIUM-ID database. Among the recovered isolates, Fusarium oxysporum was the most prevalent species (33%), followed by F. acuminatum (21%), F. avenaceum (15%), F. redolens (14%), F. culmorum (6%), F. sporotrichioides (6%), Neocosmospora solani (6%), F. equiseti (2%), F. torulosum (0.9%), F. gamsii (0.8%), F. proliferatum (0.2%), F. pseudograminearum (0.2%), and F. brachygibbosum (0.1%). The aggressiveness of a subset of 51 isolates representing various Fusarium spp. was tested on chickpea cv. ‘CDC Frontier’. A non-parametric variance analysis conducted on disease severity ranks indicated that F. avenaceum isolates were highly aggressive. This study reports for the first time that F. gamsii, F. proliferatum and F. brachygibbosum are causal agents of root rot in chickpea in the United States. This knowledge is invaluable for making informed decisions regarding crop rotation, disease management, and developing resistant chickpea varieties against economically significant Fusarium pathogens.