Productivity and persistence of cultivars and Algerian introductions of perennial ryegrass (Lolium perenne L.) in Victoria

摘要

We assessed the main Australian and New Zealand cultivars and a selection of Algerian introductions of perennial ryegrass at 3 sites in Victoria, 1 of which was irrigated. Seasonal yields of herbage, persistence and the presence of the ryegrass endophyte (Acremonium loliae) were assessed. At Drumborg (dryland), Ellett was the most productive cultivar over 3 years (9.25 t/ha DM total). At the other dryland site, Hamilton, the cumulative yields over 4 years were highest from the cultivars Kangaroo Valley Early (14.57 t/ha DM), Victorian (14.45 t/ha DM) and Ellett (13.80 t/ha DM); lesser yields were obtained from Grasslands Nui (12.92 t/ha DM) and Grasslands Ruanui (1 1.25 t/ha DM). At Numurkah, under irrigation. the yield of 4 cultivars, Ellett (22.14 t/ha DM total), Grasslands Nui, Kangaroo Valley Early and Victorian, were not different (P> 0.05) over 3 years. Differences between cultivars in patterns of growth were occasionally noted, particularly the higher rate of growth of Kangaroo Valley Early in winter. Under irrigation, Ellett and Grasslands Nui sometimes gave higher rates of growth than other cultivars during late spring and summer ( P < 0.05). Seed of 6 accessions from Algeria, which had been produced in Victoria from old plots, was sown for comparison with the commercial cultivars at Hamilton. The accessions grew poorly in the establishment year but later were as productive as the cultivars. Leaf sheaths were examined in year 4, for presence of the ryegrass en,dophyte (Acremonium loliae) in plants surviving the 1982-83 drought. Only plots of Ellett and Victorian contained high proportions of endophyte-infected plants (> 60% of plants infected). Relative to other entries, Ellett maintained a high plant density at all 3 sites. However, at 2 sites, Victorian and Grasslands Nui maintained a similar density to Ellett, and all the Algerian lines sown at Hamilton maintained a similar density to Ellett.