Coevolutionary patterns in the Linum marginale - Melampsora lini association at a continental scale

2002 ◽  
Vol 80 (3) ◽  
pp. 288-296 ◽  
Author(s):  
J J Burdon ◽  
P H Thrall ◽  
G J Lawrence

Patterns in the distribution of virulence and resistance in the Linum marginale A. Cunn. ex. Planch – Melampsora lini (Ehrenb.) Lev. host–pathogen interaction that is endemic to Australia were examined in a 3500-km pancontinental comparison. Pathogen isolates derived from Western Australia were virulent on a much greater proportion of hosts from Western Australia than they were on a broad range of L. marginale lines collected throughout eastern Australia. In contrast, the physical isolation of Western Australia had no discernible effect on the distribution of the mean resistance of host lines. Within eastern Australia, isolates collected from Tasmania (isolated by 100 km of sea), southern New South Wales, and South Australia showed varying levels of response in terms of their virulence on host lines originating from the same or other eastern subregions. Finally, across the entire distribution of the pathogen, there was a significant effect of distance such that more distant pathogen isolates were generally less well adapted to host lines than more locally derived ones.Key words: coevolution, pathogen, resistance, rust, speciation, virulence.

2017 ◽  
Vol 30 (4) ◽  
pp. 337
Author(s):  
A. E. Orchard

The present paper completes a revision of the endemic Australian genus Cassinia R.Br. Cassinia subgenus Achromolaena comprises two sections, namely, section Achromolaena of seven species (C. laevis, C. arcuata, C. uncata, C. tenuifolia, C. collina, C. subtropica, and C. quinquefaria), and Cassinia section Siftonia, which contains two species (C. sifton and C. theodorii). Cassinia laevis is divided into western (C. laevis subsp. laevis) and eastern (C. laevis subsp. rosmarinifolia (A.Cunn.) Orchard, comb. et stat. nov.) taxa. Examination of the type of C. arcuata showed that this name is synonymous with C. paniculata, and applies to a relatively rare taxon with whitish capitula arranged in short erect compact panicles, and found in Western Australia, the midlands of South Australia, western Victoria and (formerly) south-western New South Wales. Furthermore, it belongs to section Achromolaena. The taxon with red to brown capitula, widespread throughout south-eastern Australia, which until now has been (incorrectly) known as C. arcuata (Sifton bush) is distinct, but lacks a published name. The name Cassinia sifton Orchard, sp. nov. is here proposed for this taxon. An unfortunate outcome of this discovery is that the sectional name Cassinia section Arcuatae, with C. arcuata as type, becomes synonymous with section Achromolaena. The new name Cassinia section Siftonia is proposed to accommodate Sifton bush (C. sifton) and its narrowly endemic sister species C. theodorii. A summary of the whole genus is provided, with keys to all taxa. Three former subspecies of C. macrocephala are raised to species rank (C. petrapendula (Orchard) Orchard, C. storyi (Orchard) Orchard, C. tenuis (Orchard) Orchard), and it is suggested that C. furtiva Orchard may be conspecific with C. straminea (Benth.) Orchard.


1987 ◽  
Vol 40 (2) ◽  
pp. 125 ◽  
Author(s):  
MF Uren ◽  
T D St George ◽  
PD Kirkland ◽  
RS Stranger ◽  
MD Murray

Bovine ephemeral fever is an important viral disease of cattle in Australia. The disease occurred each year, principally in summer and autumn, between 1981 and 1985. Queensland and the northern half of New South Wales were areas of greatest activity with only sporadic cases being reported from the Northern Territory and the northern third of Western Australia. Since 1981, the disease has been endemic in an extensive area of eastern Australia and has tended to occur in widely scattered outbreaks rather than the north-south advancing wave form of the epidemics of 1936-37, 1967-68, 1970-71 and 1972-74. The southernmost outbreaks between 1981 and 1985 were well within the limits of these earlier epidemics. The pattern of disease appears to have become seasonally endemic rather than periodically endemic in the northern two-thirds of eastern Australia. Ephemeral fever was not recorded in Victoria, Tasmania, South Australia or the southern part of Western Australia between 1981 and 1985


2013 ◽  
Vol 41 (2) ◽  
pp. 265-298
Author(s):  
Peter Congdon

Constitutional systems of Westminster heritage are increasingly moving towards fixed-term parliaments to, amongst other things, prevent the Premier or Prime Minister opportunistically calling a ‘snap election’. Amongst the Australian states, qualified fixed-term parliaments currently exist in New South Wales, South Australia and Victoria. Queensland, Tasmania and Western Australia have also deliberated over whether to establish similar fixed-term parliaments. However, manner and form provisions in those states' constitutions entrench the Parliament's duration, Governor's Office and dissolution power. In Western Australia and Queensland, unlike Tasmania, such provisions are doubly entrenched. This article considers whether these entrenching provisions present legal obstacles to constitutional amendments establishing fixed-term parliaments in those two states. This involves examining whether laws fixing parliamentary terms fall within section 6 of the Australia Acts 1986 (Cth) & (UK). The article concludes by examining recent amendments to the Electoral Act 1907 (WA) designed to enable fixed election dates in Western Australia without requiring a successful referendum.


Author(s):  
D. W. Minter

Abstract A description is provided for Podospora excentrica. Some information on its associated organisms and substrata, dispersal and transmission, habitats and conservation status is given, along with details of its geographical distribution (South America (Venezuela), Atlantic Ocean (Portugal (Madeira)), Australasia (Australia (New South Wales, South Australia, Victoria, Western Australia)), New Zealand, Europe (Belgium, Denmark, Germany, Ireland, Italy, Netherlands, Spain, Sweden, UK)).


Author(s):  

Abstract A new distribution map is provided for Phytoplasma australiense [Candidatus] R.E. Davis et al. Bacteria: Phytoplasmas Hosts: Grapevine (Vitis spp.), pawpaw (Carica papaya) and Phormium tenax. Information is given on the geographical distribution in OCEANIA, Australia, New South Wales, Queensland, South Australia, Victoria, Western Australia, New Zealand.


1988 ◽  
Vol 78 (3) ◽  
pp. 493-509 ◽  
Author(s):  
Garrick McDonald ◽  
Roger A. Farrow

AbstractAerial sampling for Nysius vinitor Bergroth was undertaken in the surface and upper air, at altitudes of 2 and 100-300 m, respectively, at Trangie in central New South Wales and at Corny Point, Yorke Peninsula, South Australia. Insects were sampled for 15 periods, each of 3-11 days, between October 1979 and February 1984, covering all months except January, March and May. N. vinitor was one of the most abundant insects caught in the upper air during the day and night (mean density of 652/106 m3), while the congeneric N. clevelandensis Evans was rarely caught at any time. N. vinitor was caught in all months sampled except for the winter months of July and August, and the largest daily catches occurred in September. Females were generally less common than males, although the relative incidence in the upper air catches frequently increased significantly from day to night. Fewer mature females were caught in the upper air (0-16·8%) than at the surface (0-48·4%). Densities were generally much greater in the surface air than in the upper air, although during the major flights of spring, there was less than a two-fold difference, indicating increased migratory activity. Migration occurred in a range of synoptic conditions resulting in the displacement of individuals in a variety of directions and distances depending on synoptic flow at the time of flight. Major migrations occurred at night, following dusk take-off, in disturbed weather associated with prefrontal airflows. These resulted in net southward displacements of ca 200-300 km depending on flight duration. It is suggested that major immigration flights into central-western New South Wales and regions to the south regularly occur in early spring (September-October) and probably arise from breeding areas in subtropical latitudes.


1996 ◽  
Vol 47 (7) ◽  
pp. 1095 ◽  
Author(s):  
MJ Hill

Potential adaptation zones were modelled for major temperate pasture species using climate data and knowledge-based logical rules. A GIs database was constructed using a 0.025 degree digital elevation model and the Australian Climate Surfaces to create layers of monthly mean climate data for Australia. Soil pH maps for New South Wales, Victoria, and south-eastern South Australia were digitised and added to the database. Simple models using logical operators were constructed using estimates of temperature and aridity thresholds for the main temperate pasture species. The logical models were executed using primary and derived climate layers to create raster maps of potential adaptation zones for pasture species in eastern and south-western Australia. Areas of adaptation on freehold/leasehold land were expressed relative to a potential temperate pasture adaptation zone described by the lower (arid) limit of annual legume adaptation in temperate Australia and the northern limit of lucerne adaptation. Potential adaptation within this area ranged from 66% for lucerne down to <20% for perennial ryegrass in eastern Australia, and 93% for subterranean clover down to zero for perennial ryegrass in south-western Australia. Utility of the species adaptation zones could be enhanced using soil pH maps: a zone for serradella in NSW was refined by restricting adaptation to areas of climatic suitability with low soil pH. Maps for lucerne and Mount Barker subterranean clover showed good agreement with validation data for NSW. The zones may be readily adjusted by simple changes to parameter values in the algorithms. This knowledge-based approach has potential as an aid to targeting resources for plant improvement or to provide advice for more efficient utilisation of existing commercial pasture plants.


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