Phenotypic traits in natural perennial ryegrass populations and relations to climate conditions at sites of origins across Europe

Perennial ryegrass (Lolium perenne L.) is one of the most important forage grass species in temperate climates. However, natural perennial ryegrass populations have been exploited to only a limited extent by breeders. Therefore, 41 ecotypic Lolium perenne populations collected across Europe were studied for their agronomic performance in a 3-year common garden experiment located in north-eastern Germany (Poel Island, Mecklenburg Western Pomerania). Agronomic performances were evaluated on 30 plants per population for 11 traits related to forage value and environmental adaptation. Population means for studied traits were correlated to the values of climate variables at their collection sites. Populations clearly differed in their phenotypic performance, and eight populations originating from Belgium, France and Germany outperformed the other populations by showing the lowest winter damage, strongest spring growth and regrowth capacity after cuts and low disease susceptibility. Specifically, in the first experimental year, trait performances, in particular winter damage, spring growth and heading date, were related to the local climate at the site of origin of populations. Acclimation to the climate conditions at the experimental site might explain why these correlations were less pronounced in the second and third experimental years. The characterized populations might now be considered to improve specific traits in breeding.