Current Virulence of Pyrenophora teres on Barley in Western Australia

Abstract

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.

Virulence of MoroccanPyrenophora teresf.teresRevealed by International Differential Barley Genotypes

“…Later reports on pathogen variability suggested that isolates originating from North African region were highly variable (Douiyssi et al 1998;Bouajila et al 2012). Highly variable Ptt populations were reported by Tuohy et al (2006) in Ireland and Northern Europe, Jonsson et al (1997) in Nordic region, Gupta and Loughman (2001) in Australia, Cromey and Parkes (2003) in New Zealand, and Liu et al (2012) in ND of the USA. Of 15 Moroccan Ptt isolates tested on 38 barley genotypes by Douiyssi et al (1998), none of the isolates were found identical and could not be considered for clustering into similar virulence groups.…”

“…Helminthosporium teres) causing the net form of net blotch (NFNB) [P. teres f. teres] (Ptt) and spot form of net blotch (SFNB) [P. teres f. maculata] (Ptm) of barley (Rau et al 2015), are the most important factors limiting successful barley production. Net blotch has become a serious disease in the dry areas of North Africa (Jebbouj and El Yousfi 2010;Bouajila et al 2013), Europe (Tuohy et al 2006), Nordic region (Jonsson et al 1997), USA (Liu et al 2012) and Australia (Gupta and Loughman 2001). Specifically in Morocco, the net form of net blotch (Ptt) is reported as more prevalent than the spot form of net blotch (Ptm) (Harrabi and Kamel 1990;Yousfi and Ezzahiri 2001).…”

Mapping and validation of the genes for resistance to Pyrenophora teres f. teres in barley (Hordeum vulgare L.)

“…Two isolates used in the validation experiment were from Western Australia (Gupta and Loughman 2001) and one from Queensland. Our data indicated that one common resistance gene was effective against all of these pathotypes.…”

“…One population was derived from a cross between barley varieties Pompadour (FDO192/Patty) and Stirling (Dampier//Prior/ Ymer/3/Piroline) and the other from a cross between WPG8412 (Bowman//Ellice/TR451) and Stirling. These populations were screened with NTNB pathotypes from Western Australia (95NB100 and 97NB1) and Queensland (NB81) at the seedling stage using the screening procedure of Gupta and Loughman (2001). For the marker validation, bulk segregant analysis (BSA) was employed (Michelmore et al 1991).…”

Resistance in cultivated barleys to Pyrenophora teres f. teres and prospects of its utilisation in marker identification and breeding

“…Dampier, and Poulsen et al (1999) reported over 50% losses in Queensland. In Western Australia, most of the cultivars have been susceptible and recent virulence studies indicated that 2 main virulences have remained unchanged in this region over a 20-year period (Gupta and Loughman 2001). Elsewhere in Australia, the variability of NTNB virulence is higher, and the breakdown of resistance in cvv.…”