Evaluación de la susceptibilidad al marchitamiento por Fusarium en especies de Passiflora mediante inoculación artificial

Genetic resistance to Fusarium spp. is the most effective alternative for controlling vascular wilt in passionflower. [Objective] To standardize an artificial inoculation method with Fusarium solani (FS) in passionfruit (Passiflora edulis f. flavicarpa) and cholupa (Passiflora maliformis) plants reproducing the disease symptoms and allowing the assessment of susceptibility to the pathogen using a severity scale. [Methodology] Two experiments were evaluated in a randomized complete block design with seven replicates, including uninoculated controls. The first experiment consisted of inoculating the substrate with three concentrations (1 × 10⁶, 1 × 10⁷, and 1 × 10⁸ conidia g⁻¹ of substrate) using a stem incision method with the aggressive isolate FS (HU-1). The second experiment evaluated the inoculation of five Fusarium isolates. Incidence and mortality were measured, as well as the incubation period (IP), leaf severity (HS), and root collar severity (RCS) using the area under the disease progression curve. Data were analyzed by non-parametric analysis of variance using Kruskal-Wallis or Mann-Whitney tests, and differences between treatments were established using the Dunn’s test, with a custom R script using the ggstatsplot package. [Results] Inoculation of the substrate with 1 x 10⁷ conidia g⁻¹ of substrate showed intermediate behavior in some of the evaluated variables, compared to the highest concentration used, indicating its usefulness in screening materials for susceptibility to infection with FS. Differential behavior was observed in the expression of the resulting symptoms; HU-2.1 (FO), FUS2 (FO), and HU-1 (FS) caused more severe symptoms. [Conclusion] The potential use of the artificial inoculation method with a substrate concentration of 1 x 10⁷ conidia g⁻¹ for evaluating susceptibility to Fusarium was demonstrated. The results suggest a lower susceptibility of P. maliformis to F. solani, highlighting the need to incorporate additional evaluation parameters to establish resistance.