engleski

Susceptibility of Fraxinus angustifolia clones to Hymenoscyphus fraxineus in lowland Croatia

Nutrition status of the ash host could play an important role in resistance to the Hymenoscyphus fraxineus according to obtained preliminary results on three types of agar medium with leaf extracts from native Fraxinus species. Experiment revealed the fastest growth of the pathogen isolates on agar enriched with F. excelsior leaf extract, followed by the agar with F. ornus leaf extract, and the slowest growth was obtained on the agar with F. angustifolia leaf extracts. Study on narrow- leaved ash resistance to the pathogen revealed significant differences between nine tested clones, among which the clones BJ25, BJ38, NG03 and NG31 turned out to be the less susceptible to the H. fraxineus. Significant differences were obtained also between genotypes in clonal seed orchards for leaf unfolding parameter. Earlier leaf unfolding was obtained in clone NG03 which revealed smaller necrosis in inoculation experiment, while the clone NG55 revealed later leaf unfolding and longer necrosis lengths, leading to conclusion that phenology could play an important role in narrow-leaved ash clones' resistance to H. fraxineus.

Narrow-leaved ash ; clones ; fungal pathogen ; resistance

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