Evaluation of winter hardiness in Romanian introductions of Lolium perenne

Abstract

SummaryCharacterization of accessions of Lolium perenne collected in Romania, using naturally hardened tillers in an artificial freezing test, is described. Accessions showed contrasting hardening response to variation in the winter environment at Aberystwyth. Cold tolerance of the accessions, measured as lethal temperature for 50% of the tillers (LT50), was positively correlated with the mean temperature of the coldest month at the sites of origin and with persistence in swards after three winters. Superior populations were identified within this collection and are being used as a source of winter hardiness in a breeding programme.The role of temperature and irradiance in the contrasting hardening responses of three accessions was investigated in controlled-environment studies with seedlings.The advantages of environmental simulation techniques for characterization of genetic resources are discussed.