Badania nad zamieraniem jesionu w drzewostanach Nadleśnictwa Rokita
Tadeusz Kowalski , Wojciech Kraj , Tomasz Szeszycki
AbstractThe studies were carried out in Rokita Forest District in 14 ash stands and in 2 newly established experimental plots, where 500 seedlings of F. excelsior per each plot were planted in 2010. The purpose of the studies were: 1. identification of disease symptoms in tree stands of different age, 2. evaluation of ash seedlings dieback in newly established plantations, 3. identification of fungi within the necroses on the main shoots and branches of ash, 4. characterization of infectious material reservoir of H. pseudoalbidus and 5. search for potential molecular markers linked to resistance of F. excelsior to the disease process. As far as the majority of examined tree stands is concerned, medium or severe intensity of ash disease was observed (Tab. 1). The most common symptoms included death of whole branches or their apices, tree-top dieback, crowns defoliation, local necroses on the trunks and twigs, growth of epicormic shoots from trunks and along the bases of living branches. The extend of disease was larger in the stands of lower age classes (Tab. 1). Within the necrotic tissues of trunk and branches of the first and second age class 44 species of fungi were found (Tab. 2). The most common species isolated was Chalara fraxinea (teleomorph: Hymenoscyphus pseudoalbidus). Other fungi often obtained during isolation were: Botryosphaeria stevensii, Cytospora sp., Fusarium avenaceum, F. lateritium and Phomopsis sp. 1 (Tab. 2). The most common fungi developing the fruitbody on shoots were: B. stevensii, Cytospora sp., Massaria sp. and Phomopsis sp. 1. Infectious material of Hymenoscyphus pseudoalbidus was observed in the litter of analyzed tree stands in the summer season (Tab. 1). The evaluation of the health status of F. excelsior seedlings from two experimental plots is presented in Table 3. Only 36.2% of seedlings did not show any symptoms of dieback of main or side shoots in the third year of growth on the plot in Moracz. There were 57.2% of asymptomatic seedlings on the plot in Samlino. 32 species of fungi were identified in necrotic tissues of ash shoots in those plots (Tab. 4). C. fraxinea was isolated most often (70.0% of main shoots). The other commonly isolated fungi were Alternaria alternata, B. stevensii, F. avenaceum, F. lateritium i Phomopsis sp. 1. Fruitbodies on shoots were most often developed by B. stevensii, Cytospora sp. 1, Massaria sp. and Phomopsis sp. 1. Fruibodies most rarely appeared on the top segment of ash stems (Fig. 1). Phomopsis sp. 1 developed fruitbodies mainly on the basal parts of stems (Fig. 2). The Bulked Segregant Analysis (BSA) was used to identify random amplified polymorphic DNA (RAPD) markers linked to ash dieback disease resistance. Bulks were screened in two ash populations using 720 random primers. Two RAPD markers (generated with the use of A02 and M20 primers) were found to be linked to disease resistance. Frequency of markers occurrence was different in both populations and ranged from 70 to 100%.
|Other language title versions||The studies on ash decline in Rokita Forest District stands|
|Journal series||Acta Agraria et Silvestria series Silvestris, ISSN 0065-0927, (B 1 pkt)|
|Publication size in sheets||0.95|
|Keywords in Polish||Fraxinus excelsior, zamieranie jesionu, Hymenoscyphus pseudoalbidus, Chalara fraxinea|
|Keywords in English||Fraxinus excelsior, ash decline, Hymenoscyphus pseudoalbidus, Chalara fraxinea|
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