Differences in susceptibility to ash dieback in Czech provenances of Fraxinus excelsior

Abstract

Summary The impact of ash dieback caused by Hymenoscyphus fraxineus on 17 provenances of Fraxinus excelsior and one provenance of Fraxinus angustifolia was studied in an extensive field trial established in the Czech Republic prior to the H. fraxineus invasion in 1999. A difference in the level of resistance to ash dieback between the species was found: F. angustifolia was significantly less affected by the disease than F. excelsior. Moreover, particular provenances of F. excelsior showed important differences in the level of resistance to H. fraxineus. A relationship between the impact of ash dieback and altitude was also discovered – the provenances from altitudes above 600 m a.s.l. were less affected by the pathogen than were the provenances from lower areas. No difference in the impact of the disease among provenances of F. excelsior from different ecotopes (ravine, calcareous ravine and alluvial) was found. Substantial among‐tree variability in resistance to H. fraxineus was observed throughout the trial – promising genotypes (with crown defoliation up to 5%) were identified in all 18 tested provenances. In regard to this finding, it appears that the main source of resistance to the pathogen is probably at the individual genotype level in the trial. A secondary but massive attack by Hylesinus fraxini was identified in the trees that had been greatly damaged by ash dieback, and the beetle caused their health to deteriorate significantly. A significant negative effect of the presence of collar necroses caused by H. fraxineus and browse damage was also identified.

Effect of fungal pathogens and climatic factors on production, biodiversity and health status of ash mountain forests

“…Study of 17 ash provenances showed, that the provenances from altitudes above 600 m a.s.l. were less affected by the pathogen than those from lower areas (Havrdová et al, 2016). Similarly, decrease in foliation (14.6%) and biodiversity (2.3%) was significantly lower compared to other plots on PRP 42 characterized by high altitude, but also by low groundwater depth and the lowest species richness and diameter differentiation among all plots.…”

“…Selection of vital trees prefers relatively resistant trees originating from the local environmental conditions (McKinney et al, 2011;Lobo et al, 2014). Provenance trials of F. excelsior showed important differences in the level of resistance to pathogen, but main source of resistance is at the individual genotype level (Havrdová et al, 2016).…”

“…Interactions between fungal pathogen and host tree are particularly important in relation to global climatic changes, with respect to reproduction, distribution and survival (Kowalski, 2016). Ash dieback is also closely connected with silvicultural practices, such as thinning of suppress trees susceptible to diseases and infected trees, suitable changes of tree species composition, selection of resistant genotypes and others (Dobrowolska et al, 2011;Skovsgaard, 2013;Havrdová et al, 2014Havrdová et al, , 2016.…”

Evaluating the impact of Hymenoscyphus fraxineus in Trentino (Alps, Northern Italy): first investigations

“…The concern about the ecological impact of this invasion is confirmed by several investigations carried out throughout Europe (Enderle et al 2013, Havrdová et al 2016, Hobson et al 2016, Queloz 2016. Recently, the recovering of surviving plants in affected areas open up new possibilities for characterization and breeding of hyposensitive trees (Kjaer et al 2011, Havrdová et al 2016, Enderle et al 2017a).…”

“…Recently, the recovering of surviving plants in affected areas open up new possibilities for characterization and breeding of hyposensitive trees (Kjaer et al 2011, Havrdová et al 2016, Enderle et al 2017a). …”