Persistence of winter-active phalaris breeding populations, cultivars and other temperate grasses in diverse environments of south-eastern Australia

Abstract

Three winter-active populations of phalaris (Phalaris aquatica L.), selected over two generations for improved persistence under grazing, were evaluated with commercial cultivars of phalaris and other temperate perennial grasses from 1999–2003 in three environments of south-eastern Australia as part of a program to develop a cultivar for more sustainable pastures and to assess genotype × environment interaction. Grazed sites were located at Bulart in western Victoria, and Rye Park on the Southern Tablelands and Tamworth on the North West Slopes of New South Wales. At the conclusion of the experiment, the frequency of live plant base was highest at Rye Park despite soil acidity and drought. Significant variance among half-sib families in each population was also observed most frequently at this site. Frequency was intermediate at Bulart but lower than expected considering high soil fertility, probably because of high grazing pressure. Frequency was lowest at Tamworth where severe drought occurred from 2001 onwards. There was significant genotype × environment interaction for frequency among half-sib families. Significant common family variance for frequency across the Bulart and Rye Park sites was demonstrated, but not between Tamworth and either of the other sites in later years. The relationship between winter herbage mass potential and persistence differed with population and site, and was negative for one population at Bulart but positive for another population at Tamworth. Mean persistence of all families was 30% higher than winter-active controls at Rye Park and at least 40% higher at Bulart. Phalaris generally persisted better than cultivars of tall fescue (Festuca arundinacea Schreb.), cocksfoot (Dactylis glomerata L.) and perennial ryegrass (Lolium perenne L.) with some exceptions, particularly at Bulart. Development of a winter-active phalaris cultivar with improved persistence under grazing was considered possible for the Southern Tablelands and western Victorian environments with these populations but a separate program using additional germplasm will be needed for the North West Slopes environment.

Field evaluation of perennial grasses and herbs in southern Australia. 1. Establishment and herbage production

“…The poor persistence of summer-active grasses, viz. AU Triumph tall fescue, when compared with the summer dormant cultivar, Fraydo, and Yatsyn 1 perennial ryegrass, when compared with AVH 4, has been observed previously at other sites in NSW and Victoria (Culvenor et al 2007).…”

Herbage production and persistence of two tropical perennial grasses and forage sorghum under different nitrogen fertilization and defoliation regimes in a summer‐dominant rainfall environment, Australia

“…In inland northern NSW, temperate species have traditionally been sown, with Phalaris aquatica (phalaris) and Festuca arundinacea (tall fescue) being the most persistent temperate grass species (Archer, ; Harris and Culvenor, ; Culvenor et al ., ). However, on the North West Slopes, these species fail to persist 5 years (Reeve et al ., ) making them uneconomical (Scott et al ., ).…”

Interaction of plant genotype and management in the persistence of a perennial grass exposed to grazing and soil fertility stresses

“…Australian and lower persistence of the Sirosa and Holdfast type of winter‐active cultivar (e.g. Culvenor et al ., ) under a high rate of continuous stocking were confirmed. While the period of our study was short compared with the planned life of long‐term pastures (20+ years), there was strong evidence that Holdfast GT had higher tolerance of grazing stress, particularly in the first treatment year, than the other winter‐active cultivars.…”

“…This may reflect selection of Landmaster on low fertility sites with periods of grazing (Oram, ). These results support earlier evidence of superior persistence under heavy continuous stocking by the populations from which Holdfast GT was selected (Culvenor et al ., , ).…”

“…Winter‐active phalaris cultivars have higher autumn–winter growth rates than the original semi‐winter‐dormant introduction, cv. Australian, but tend to be less tolerant of heavy grazing due to their more erect, less densely tillered and spreading growth habit (Culvenor, ; Culvenor et al ., ). A winter‐active cultivar, Holdfast GT, bred for improved persistence under heavy grazing pressure has been released recently (Culvenor and Simpson, ).…”