Genetic diversity among cultivars and ecotypes of Lolium perenne L.

Perrenial ryegrass (Lolium perenne L.) is indigenous in most parts of Europe. In Germany and other countries of the temperate zone it is the most important grass species of the premanent grassland. The large variability of the crop is reflected by the high number of registered cultivars. Since the beginning of rational grass breednig, ecotypes have been used until today as an important source of new variability. However, very little is known about the genetic structure of the species. The objective of our investigation was to determine genetic diversity and to look for interrelationships among populations by means of molecular markers. On average genetic similarity (GS) was 0, 40 with a range from 0, 16 to 0, 89 across all plants analysed. Molecular variance was much larger within (cv 68%, ec 73%) as compared to among populations (cv 32%, ec 27%). On the population level GS varied from 0, 34 to 0, 51. Expressed as genetic distance (GD based on FST) the relationship among cultivars ranged from 0, 16 to 0, 45. By means of a three-dimensional PCoA a clear grouping of the populations is obvious. The M/S-ec form distinct group. The N-ec and 9 cultivars build a second group around the centre. Four cultivars are independent from the 2 groups and each other indicating diverse origin.