Disease progression and virulence potential of Xanthomonas vasicola pv. musacearum in cultivated and wild enset varies at sites with contrasting weather conditions

Over the years, screening studies on enset bacterial wilt, caused by Xanthomonas vasicola pv. musacearum (Xvm) resistance/tolerance have been limited in scope and location, failing to account for the influence of environments on disease development and progression. This study was aimed to evaluate response of cultivated and wild enset genotypes to artificial inoculation with the yellow mucoid strain of Xvm at sites with contrasting weather conditions. Potted enset plants comprising 10 genotypes (eight cultivated and two wild) were evaluated at two elevations (at 1200 masl &, at 2100 masl). The petioles of the youngest fully open leaf of 10-months-old enset plants were inoculated with 1 × 10 8 cfu/ml of Xvm, and disease progression assessed weekly over four months. Results showed that all inoculated plants showed 100% disease incidence. However, some genotypes exhibited a low disease severity up to 119 days post inoculation. The landrace Nobo (from corms) showed the lowest mortality (11%), disease severity index (66.7%) and area under the disease progress curve (466.7%-days), indicating a tolerance response, particularly at lower elevations characterized by warmer temperatures and lower humidity. On the other hand, Maze, Gena, and Checho recorded moderate mortality (44%) and were moderately susceptible. Overall findings further suggested the lack of stable tolerance response of enset genotypes over locations and underpins the role of environmental conditions in development and establishment of Xanthomonas wilt in enset. Therefore, enset screening for bacterial wilt resistance needs to be evaluated in multi-environment trials to ascertain stability across environments/sites.