scholarly journals Pathogenic variation of Pyrenophora teres f. teres on Hordeum vulgare in Australia and identification of genomic regions for resistance and susceptibility to net form net blotch

2018 ◽  
Author(s):  
Ryan Fowler
2021 ◽  
pp. 567-586
Author(s):  
Jerome D. Franckowiak ◽  
◽  
Gregory J. Platz ◽  

This chapter focuses on breeding barley for durable resistance to net and spot forms of net blotch. It starts by reviewing how Pyrenophora teres f. teres can cause net form net blotch. The chapter then goes on to examine the molecular markers that can be identified to provide resistances to net form net blotch. A section on the population dynamics of barley–P. teres f. teres interactions is also provided. The chapter also reviews how breeding crops with specific genes can help to create durable resistance to net form blotch. It moves on to discuss how Pyrenophora teres Drechs. f. maculata can cause spot form net blotch and how identifying specific molecular markers can help provide resistance to this form of net blotch. The chapter concludes by highlighting the importance of combining durable resistance to both forms of net blotch.


1996 ◽  
Vol 76 (4) ◽  
pp. 715-719 ◽  
Author(s):  
K.M. Ho ◽  
T.M. Choo ◽  
A. Tekauz ◽  
R.A. Martin

An investigation was initiated to study the genetics of resistance to three isolates of Pyrenophora teres (WRS102, WRS858, and WRS857), which have been routinely used for screening for net blotch resistance in Canada. The F1, F2, and doubled-haploid lines were derived from a Leger/CI9831 cross of barley (Hordeum vulgare L.). These materials, along with their parents, were inoculated with each of the three isolates at the three-leaf stage in growth chambers. Results showed that resistance to WRS102 was controlled by three recessive genes, resistance to WRS858 by one recessive gene, and resistance to WRS857 by either one dominant gene or two complementary genes. One of the WRS102-resistance genes appeared to be on chromosome 2 and another linked to the WRS858-resistance gene. Resistance to these three isolates was not associated with awn type, esterase 1, and esterase 5. Selection for resistance to WRS102 and WRS858 would be more effective than selection for resistance to WRS857 in a conventional breeding program. Key words: Barley, Hordeum vulgare, net blotch, Pyrenophora teres, haploids


2008 ◽  
Vol 88 (1) ◽  
pp. 257-266
Author(s):  
M. Cherif ◽  
S. Rezgui ◽  
P. Devaux ◽  
M. Harrabi

The effect of spike type on net blotch resistance is not fully understood in barley (Hordeum vulgare L.). A doubled-haploid barley population derived from a cross between a susceptible two-row (Roho) and a resistant six-row (line 90) genotypes was used to study the genetics of net blotch resistance and to determine the effect of spike type on net blotch resistance at the adult plant growth stage across three environments. Net blotch rating was evaluated using a mass disease index, area under the disease progress curve and the apparent infection rate. Partial resistance to Pyrenophora teres was observed in many DH lines and in the parental line 90 in the three environments. This result indicated that selecting for partial resistance is feasible under severe net blotch conditions where differential responses among DH lines were noted as in Mograne in 2003–2004. The normality test and/or the means comparison method suggested that additive × additive epistasis effects influenced the expression of all disease parameters in the three environments. Both the coefficient of skewness and the number of transgressive lines indicate the presence of a complementary gene interaction for most disease parameters. Results showed that two-row lines were particularly associated with net blotch resistance in Mograne 2002–2003 and in Tunis greenhouse 2004. A strategy for improving the level of quantitative resistance to P. teres in later generations is recommended. Key words: Hordeum vulgare, doubled-haploid population, quantitative resistance, Pyrenophora teres, net blotch, genetic analysis


2012 ◽  
Vol 102 (5) ◽  
pp. 539-546 ◽  
Author(s):  
Z. H. Liu ◽  
S. Zhong ◽  
A. K. Stasko ◽  
M. C. Edwards ◽  
T. L. Friesen

A Pyrenophora teres f. teres population in North Dakota was analyzed for virulence variation and genetic diversity using 75 monospore isolates that were collected across a 4-year period (2004 to 2007) from two North Dakota State University agricultural experiment stations at Fargo and Langdon. Pathogenicity tests by inoculation onto 22 barley differential lines at seedling stage revealed 49 pathotypes, indicating a wide range of pathogenic diversity. Two-way analysis of variance of disease ratings revealed a significant difference in the virulence among isolates and in the resistance among barley lines, as well as in the interactions between the two. ‘CI5791’, ‘Algerian’, and ‘Heartland’ were three barley lines showing a high level of seedling resistance to all North Dakota isolates tested; however, many previously reported resistance genes have been overcome. Forty multilocus genotypes were identified from this set of isolates by genotyping at 13 simple-sequence repeat loci. High percentages of clonal cultures were detected in the samplings from 2005 and 2007 in Fargo and 2005 in Langdon. Using a clone-corrected sample set, the mean gene diversity (h) was estimated to be 0.58, approximately the same for both locations. The calculated Wright's FST value is small (0.11) but was significantly >0, indicating a significant differentiation between the Fargo and Langdon populations. In the gametic disequilibrium test, only 3 of 78 possible pairwise comparisons over all isolates showed significant (P < 0.05) nonrandom association, suggesting a random mating mode. Our results suggest that the populations from the two locations are derived from a common source and undergo frequent recombination. This research provides important information for barley breeders regarding development and deployment of cultivars with resistance to net form net blotch in this region.


1998 ◽  
Vol 78 (2) ◽  
pp. 217-222 ◽  
Author(s):  
M. J. Edney ◽  
T. M. Choo ◽  
D. Kong ◽  
T. Ferguson ◽  
K. M. Ho ◽  
...  

Kernel colour is an important marketing trait for both malting and feed barleys. Therefore a study was initiated to investigate the kernel colour of 75 Canadian barley (Hordeum vulgare L.) cultivars at three locations (Charlottetown, Ottawa and Bentley) across Canada in 1991 and 1992. Kernel colour was measured by an Instrumar Colormet Spectrocolorimeter. Kernel colour was found to be brighter at the two locations in eastern Canada (Charlottetown and Ottawa) than at the location in western Canada (Bentley). Two-row cultivars on average were more discoloured than six-row cultivars; eastern two-row were more discoloured than western two-row. Covered barleys were less discoloured than hulless barleys in five of the six environments, but covered barleys at Bentley in 1992 were more discoloured than hulless barleys. Kernel discolouration appeared to be associated with susceptibility to net blotch for six-row cultivars. More studies are needed on kernel discolouration of barley. Key words: Barley, Hordeum vulgare, kernel colour


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