DISTRIBUTION OF NEOTYPHODIUM LOLII IN LOLIUM PERENNE CULTIVARS AND ECOTYPES IN CENTRAL EUROPE
A HOLZMANN, J REINHOLZ, H OSTBOMKE and VH PAUL
Universitat-Gesarnthochschule Paderborn, Department of Agriculture, Luebecker Ring 2, D-59494 Soest, Germany
Background and objectives
Grasses of the family Poaceae can be infested by symbiotic fungi of the genus Neotyphodium. The fungi are strictly seed transmitted and can enhance their host's resistance against biotic and alliotic stresses, but may also produce alkaloids toxic to livestock. Livestock toxicoses have been first reported from New Zealand and the USA, where infestation levels in fodder grasses, Festuca and Lolium species, are often more than 90%. As Central Europe is the origin of these fodder grasses, this symbiosis is presumed to originate from there. Despite this, problems with livestock are rarely reported in Europe and infestation levels in varieties and ecotypes are widely unknown.
The objective of this paper was to investigate the distribution of Neotyphodium in European Lolium perenne ecotypes and varieties, respectively. The influence of long-term storage is discussed.
Materials and methods
Seed lots of 84 L. ;perenne cultivars from the German list of registered cultivars (Beschreibende Sortenliste) and 53 Romanian ecotypes were examined for presence of endophytes. Grass seeds were stained with aniline blue and examined microscopically for fungal hyphae. To investigate the influence of long-term storage on the viability of the endophyte, ecotype seed was germinated and the seedlings examined for endophyte presence. A total of 24 plants per seed lot sown before and 100 young plants per seed lot sown after a 3-year storage period were tested to discover whether the endophyte is transmitted to all caryopses of a positive plant. We also investigated seeds obtained from the 3-year-old plants (100 seeds each from selected plants).
Results and conclusions
From 84 cultivars of the German list of registered cultivars, 110 were Neotyphodium-infested. The infestation rate ranged from 2 to 15%. Of the 53 Romanian ecotypes, 24 were infested, and here the infestation rate was more than 81% in 17 ecotypes. This difference between infestation levels in European cultivars and European ecotypes has been reported before . A possible explanation of this could be storage under conditions unfavourable for the endophyte during the breeding process. It is reported that endophytes in seeds loose their viability sooner than the embryo under the same conditions .
Under storage conditions of 40% relative humidity at 8-18°C we found very little loss of viability of the endophyte. After a 3-year storage period of 24 endophyte-containing ecotypes, the average loss of endophyte viability in seeds was 6.3%. Investigation of the seeds of infested plants from the ecotype collection showed that some plants did not yield 100% positive seeds. Whether this fact is due to either external or genetic reasons is still unknown.
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