Novel Festuca arundinacea Shreb. and Dactylis glomerata L. germplasm to improve adaptation for marginal environments. (Sustainable pastures in marginal environments.)

摘要

Tall fescue (Festuca arundinacea Schreb., Lolium arundinceum Schreb., S.J. Darbyshire) and cocksfoot (Dactylis glomerata L.) were identified for improvement for low to medium rainfall (400-700 mm) environments where persistence of common cultivars has been unreliable. Over 200 accessions and experimental varieties of tall fescue and cocksfoot sourced from the Mediterranean basin were screened over 2 years at sites on the North-West Slopes of NSW and on the Central Highlands of Victoria, respectively. These were compared with some locally naturalised plants and most of the cultivars available in Australasia as well as cultivars developed for warm temperate and Mediterranean climates in Italy, France, Uruguay and the USA. To date, the screened accessions and experimental varieties have exhibited varying degrees of summer activity and other attributes of commercial value. Six tall fescue accessions were selected for development of synthetic varieties. These included three Sardinian accessions that after 2 years had superior persistence to cv. Demeter and recorded the highest yield scores, the mean of which exceeded that of the best performing cultivars by 34% and that of Demeter by 64%. A further three select North African accessions of tall fescue had similar yield ratings to Demeter and that of the best performing winter-active, summer-dormant cultivars. After 2 years, four Mediterranean accessions of cocksfoot were selected. These had recorded the highest yield scores, the mean of which was 34% greater than that recorded for the highest yielding cultivars and 40% greater than cv. Currie, compared with which these accessions were densely tillered and fine-leafed. The four select Mediterranean cocksfoot accessions exhibited 100% persistence; the persistence of the cultivars ranged from 31-97%. Select plants of the best performing accessions were subsequently removed from the field sites and transferred to pollen-proof glasshouse chambers for synthesis of experimental varieties. The endophyte-free tall fescue synthetics were based on Sardinian accessions selected for year round production and persistence or North African accessions that had similar yield to Demeter but with improved winter production and some summer activity. The cocksfoot synthetics were based on select plants of accessions from North Africa and included both D. glomerata and D. glomerata ssp. glomerata x spp. hispanica hybrids exhibiting persistence, dense tillering and seasonal productivity.