Summer dormancy, regeneration and persistence of perennial grasses in south-western Australia

Abstract

Autumn growth and persistence of periodically grazed, spaced plant swards of eleven perennial grasses were measured at two sites registering 750 mm and 1120 mm annual rainfall respectively. The grasses were grown on gravelly podzolic soils of moderate internal drainage and depth of A horizon. After the third summer, autumn regrowth was generally better in Phalaris tuberosa lines than in lines of Dactylis glomerata, Festuca arundinacea and Lolium perenne, Festuca arundinacea cv. Melik and D. glomerata cv. Currie regenerated better than P. tuberosa lines in the first two autumn seasons at the drier site. Capacity for autumn growth appeared to be associated mainly with the level of dormancy achieved by basal buds at mid-summer, though relatively high dormancy of one or two lines at the drier site did not prevent significant plant mortality. Numbers of reproductive tillers per plant in spring and active basal buds per tiller in late summer were less important traits affecting the growth of some lines. We think that rankings for summer dormancy would be useful for screening future introductions for wetter parts (> 750 mm annual rainfall) of the south-western region of Western Australia.