Morphological Variability and Races of Fusarium oxysporum f.sp. ciceris Associated with Chickpea (Cicer arietinum) Crops

Abstract: Problem statement: Mexico is the third largest producer and exporter of chickpea (Cicer arietinum), with the states of Sinaloa and Sonora accounting for 70 and 20% of Mexico’s production, respectively. The most damaging disease affecting this species is caused by Fusarium oxysporum f.sp. Ciceris (FOC), which causes losses of up to 60% in Sonora. The objective of this study was to isolate and characterize the phenotype and genetics of FOC collected from affected chickpea plants in northwestern Mexico and to identify the abiotic factors that allow it to develop. Approach: Sampling focused on affected plants from 12 crops in Sonora and Sinaloa. Based on 355 isolated strains, using Polymerase Chain Reaction (PCR) 161 were positive for FOC. Results: Of the 161 strains, 91 were identified as races previously recorded for the Americas: Yellowing (R0 (41%), R1B/C (15%) and wilting (R5 (14%) and R6 (28%) reflecting the symptoms observed in the areas sampled. The other 70 isolates could be nonpathogenic, or could be races yet to be recorded for the Americas. Conclusion: Morphological variability in FOC was high in the main chickpea producing regions in northwestern Mexico and was not a function of the physical and chemical properties of the soil, nor of the geographic location of the cropfields. This is the first report of races of FOC in Mexico.