Occurrence and Pathogenicity ofDrechslera teresIsolates Causing Spot-type Symptoms on Barley in Western Australia

Plant Disease ◽  
1982 ◽  
Vol 66 (1) ◽  
pp. 423 ◽  
Author(s):  
T. N. Khan
Keyword(s):  
Western Australia ◽  
Spot Type

scholarly journals Current Virulence of Pyrenophora teres on Barley in Western Australia

Plant Disease ◽  
2001 ◽  
Vol 85 (9) ◽  
pp. 960-966 ◽  
Author(s):  
Sanjiv Gupta ◽  
Robert Loughman
Keyword(s):  
Western Australia ◽  
Error Variance ◽  
Geographic Area ◽  
Australian Isolate ◽  
Pyrenophora Teres ◽  
Sources Of Resistance ◽  
Pathogenic Variation ◽  
Resistant Varieties ◽  
Significant Line ◽  
Spot Type

Studies on variation, occurrence, and distribution of virulence in Pyrenophora teres are helpful to identify effective sources of resistance that can be used for barley breeding in Western Australia. Seventy-nine isolates of Pyrenophora teres were collected from different barley fields of Western Australia in 1995-96. Seventy-four induced net type symptoms (P. teres f. teres) and five induced spot type symptoms (P. teres f. maculata). Net type isolate responses on 47 barley lines were similar to the range of responses induced by nine historical isolates collected in the region between 1975 and 1985. These net type isolates were classified into two distinct groups based on virulence to the cultivar Beecher. Isolates were further classified into eight groups based on minor pathogenic variation among the population. The virulence phenotype present in an eastern Australian isolate was not observed in any isolates collected from Western Australia. An analysis of variance on a subset of 12 net type isolates indicated a significant line × isolate interaction (P < 0.001), with the interaction term variance component four times larger than the error variance. Based on these studies, the virulence among net type isolates has remained stable in Western Australia for the last 19 years. Spot type isolates were collected from a wider geographic area than previously reported and varied in virulence based on response to barley line Herta. Variation in spot-type isolates is reported for the first time from the region. The results from this study are being used in the development of resistant varieties.

Effect of spot-type net blotch (Drechslera teres (Sacc.) Shoem) infection on barley yield in short season environment of northern cereal belt of Western Australia

1989 ◽  
Vol 40 (4) ◽  
pp. 745 ◽  
Author(s):  
TN Khan
Keyword(s):  
Western Australia ◽  
Field Experiments ◽  
Yield Loss ◽  
Yield Response ◽  
Net Blotch ◽  
Drechslera Teres ◽  
Percentage Yield ◽  
Negative Effect ◽  
Short Season ◽  
Spot Type

The effect of spot-type net blotch (Drechslera teres (Sacc.) Shoem.) on yield was studied in fourteen field experiments located at two sites over seven years in the area where the disease occurs; the northern cereal belt of south-west Western Australia. An overall reduction of 26% in grain yield occurred associated with spot-type net blotch infection. The yield losses varied depending upon season, date of sowing and cultivar. Disease was found to reduce 100 grain weight and number of ears/m2, but number of grains/ear were not affected. Regression analysis supported the above negative effect of disease on yield in general, but in a few cases disease and yield were positively correlated. The Area Under Curve (AUC) model was considered most appropriate and percentage yield loss (L) was estimated as L = 0.0233 AUC. Using this relationship, potential losses in yields of cvv. Beeeher and O'Connor were estimated to be 34% and 29%, respectively. The application of this relationship is suggested to be limited to short season environments similar to the northern cereal belt of Western Australia. A need to understand factors which modify the yield response to this disease is highlighted.

Persistence of giants: population dynamics of the limpet Scutellastra laticostata on rocky shores in Western Australia

2020 ◽  
Vol 646 ◽  
pp. 79-92
Author(s):  
RE Scheibling ◽  
R Black
Keyword(s):  
Population Dynamics ◽  
Western Australia ◽  
Size Structure ◽  
Survival Rates ◽  
Maximum Size ◽  
High Rate ◽  
Adult Survival ◽  
Rocky Shores ◽  
Adult Size ◽  
Decadal Time Scale

Population dynamics and life history traits of the ‘giant’ limpet Scutellastra laticostata on intertidal limestone platforms at Rottnest Island, Western Australia, were recorded by interannual (January/February) monitoring of limpet density and size structure, and relocation of marked individuals, at 3 locations over periods of 13-16 yr between 1993 and 2020. Limpet densities ranged from 4 to 9 ind. m-2 on wave-swept seaward margins of platforms at 2 locations and on a rocky notch at the landward margin of the platform at a third. Juvenile recruits (25-55 mm shell length) were present each year, usually at low densities (<1 m-2), but localized pulses of recruitment occurred in some years. Annual survival rates of marked limpets varied among sites and cohorts, ranging from 0.42 yr-1 at the notch to 0.79 and 0.87 yr-1 on the platforms. A mass mortality of limpets on the platforms occurred in 2003, likely mediated by thermal stress during daytime low tides, coincident with high air temperatures and calm seas. Juveniles grew rapidly to adult size within 2 yr. Asymptotic size (L∞, von Bertalanffy growth model) ranged from 89 to 97 mm, and maximum size from 100 to 113 mm, on platforms. Growth rate and maximum size were lower on the notch. Our empirical observations and simulation models suggest that these populations are relatively stable on a decadal time scale. The frequency and magnitude of recruitment pulses and high rate of adult survival provide considerable inertia, enabling persistence of these populations in the face of sporadic climatic extremes.

Antipodean Aftershocks: Group Settlement of Hebridean and non-Hebridean Britons in Western Australia following World War One

2020 ◽  
Vol 11 (2) ◽  
pp. 188-203
Author(s):  
Roy Jones ◽  
Tod Jones
Keyword(s):  
New Zealand ◽  
British Empire ◽  
Western Australia ◽  
The Sun ◽  
World War ◽  
World War One ◽  
A Site

In the speech in which the phrase ‘land fit for heroes’ was coined, Lloyd George proclaimed ‘(l)et us make victory the motive power to link the old land up in such measure that it will be nearer the sunshine than ever before … it will lift those who have been living in the dark places to a plateau where they will get the rays of the sun’. This speech conflated the issues of the ‘debt of honour’ and the provision of land to those who had served. These ideals had ramifications throughout the British Empire. Here we proffer two Antipodean examples: the national Soldier Settlement Scheme in New Zealand and the Imperial Group Settlement of British migrants in Western Australia and, specifically, the fate and the legacy of a Group of Gaelic speaking Outer Hebrideans who relocated to a site which is now in the outer fringes of metropolitan Perth.

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