Influence of grassland management on the abundance of the endophytic fungi Neotyphodium
by Lana Dobrindt
Date of Examination:2011-11-15
Date of issue:2014-11-26
Advisor:Prof. Dr. Stefan Vidal
Referee:Prof. Dr. Stefan Vidal
Referee:Prof. Dr. Johannes Isselstein
Referee:Prof. Dr. Teja Tscharntke
Persistent Address:
http://dx.doi.org/10.53846/goediss-4796
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Abstract
English
The endophytic fungus Neotyphodium spec. Glenn, Bacon and Hanlin is common in many temperate grass species. This fungus is known to enhance the resistance of its host to adverse environmental conditions and to promote its growth. In addition, Neotyphodium spec. produces a wide range of alkaloids and can therefore be toxic to livestock. Many studies dealing with this topic were conducted in the intensively managed grasslands of the USA and New Zealand. However, we still lack knowledge about the abundance of this fungus in cultivated grasslands in Europe under different management regimes. This information could contribute to a better understanding of the fungal ecology and help to assess the risk of toxicoses in European grasslands. Hence, the objective of this study was to investigate the impact of grassland management on the incidence of Neotyphodium spec. in different grass species. 1) In the rural district of Northeim (central Germany) the impact of land use intensity and type of grassland use on the incidence of Neotyphodium lolii (Latch, Christensen and Samuels), Glenn, Bacon and Hanlin in perennial ryegrass (Lolium perenne L.) was investigated in 90 managed grasslands. - The mean infection rate of L. perenne with N. lolii was low. - The intensity of land use (extensive, intermediate, intensive) and the type of grassland (pasture, mown pasture, meadow) had no influence on the abundance of the fungus. - Geology significantly influenced the incidence of N. lolii: L. perenne plants collected from sites with limestone bedrock had higher infection rates than plants from other soils. 2) The influence of fertilization, cutting frequency and sward composition on the abundance of Neotyphodium spec. in four grass species was tested in an experimental grassland in the Solling Uplands, central Germany. - Cutting frequency and sward composition did not influence the incidence of Neotyphodium spec. - Fertilization significantly increased the infection rate of the tested grass species compared to non-fertilized plots. 3) It was tested how grazing of cattle, sheep and co-grazing of cattle and sheep under different diversity regimes (high and low sward diversity) influences the abundance of Neotyphodium spec. in L. perenne and Festuca pratensis Huds. (meadow fescue). This investigation was carried out in an experimental pasture in the Solling Uplands, central Germany. - In the high diversity treatment grazing and co-grazing of cattle and sheep had no influence on the abundance of the fungus in both grass species. - In the low diversity treatment the incidence of Neotyphodium unicatum (Gams, Petrini and Schmidt) Glenn, Bacon, Price and Hanlin in F. pratensis was significantly higher in plots co-grazed by cattle and sheep compared to plots grazed by sheep only. In contrast, there was no difference in the abundance of N. lolii in L. perenne between the grazing treatment
Keywords: Endophytic fungus, Grassland management, Lolium perenne, Environmental stress, Drought stress, Grazing, Herbivores
