scholarly journals A novel way to identify specific powdery mildew resistance genes in hybrid barley cultivars

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Antonín Dreiseitl
Keyword(s):  
Powdery Mildew ◽  
Resistance Genes ◽  
Powdery Mildew Resistance ◽  
Specific Resistance ◽  
Genetic Resistance ◽  
Limiting Factor ◽  
Response Type ◽  
Barley Cultivars ◽  
Dominant Genes ◽  
Cereal Disease

Abstract Powdery mildew, a common cereal disease caused by the fungus Blumeria graminis, is a major limiting factor of barley production and genetic resistance is the most appropriate protection against it. To aid the breeding of new cultivars and their marketing, resistance genes can be postulated in homogeneous accessions. Although hybrid cultivars (F1) should be homogeneous, they are often not genetically uniform, especially if more than two genotypes are involved in their seed production or due to undesirable self-pollination, out-crossing and mechanical admixtures. To overcome these problems the accepted method of postulating specific resistance genes based on comparing response type arrays (RTAs) of genetically homogeneous cultivars with RTAs of standard genotypes was substituted by analysing the frequency of response types to clusters of pathogen isolates in segregating F2 generations. This method combines a genetic and phytopathological approach for identifying resistance genes. To assess its applicability six hybrid cultivars were screened and from three to seven with a total of 14 resistance genes were found. Two genes were newly located at the Mla locus and their heritability determined. In addition, three unknown dominant genes were detected. This novel, comprehensive and efficient method to identifying resistance genes in hybrid cultivars can also be applied in other cereals and crops.

scholarly journals Specific Resistance of Barley to Powdery Mildew, Its Use and Beyond: A Concise Critical Review

Genes ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 971 ◽  
Author(s):  
Antonín Dreiseitl
Keyword(s):  
Powdery Mildew ◽  
Resistance Genes ◽  
Plant Pathogens ◽  
Specific Resistance ◽  
Wide Spectrum ◽  
Quantitative Resistance ◽  
Spring Barley ◽  
Durable Resistance ◽  
Genetic Resistance ◽  
Barley Cultivars

Powdery mildew caused by the airborne ascomycete fungus Blumeria graminis f. sp. hordei (Bgh) is one of most common diseases of barley (Hordeum vulgare). This, as with many other plant pathogens, can be efficiently controlled by inexpensive and environmentally-friendly genetic resistance. General requirements for resistance to the pathogens are effectiveness and durability. Resistance of barley to Bgh has been studied intensively, and this review describes recent research and summarizes the specific resistance genes found in barley varieties since the last conspectus. Bgh is extraordinarily adaptable, and some commonly recommended strategies for using genetic resistance, including pyramiding of specific genes, may not be effective because they can only contribute to a limited extent to obtain sufficient resistance durability of widely-grown cultivars. In spring barley, breeding the nonspecific mlo gene is a valuable source of durable resistance. Pyramiding of nonspecific quantitative resistance genes or using introgressions derived from bulbous barley (Hordeum bulbosum) are promising ways for breeding future winter barley cultivars. The utilization of a wide spectrum of nonhost resistances can also be adopted once practical methods have been developed.

scholarly journals Virulence frequencies to powdery mildew resistance genes of winter barley cultivars

2010 ◽  
Vol 40 (No. 4) ◽  
pp. 135-140 ◽  
Author(s):  
A. Dreiseitl
Keyword(s):  
Czech Republic ◽  
Powdery Mildew ◽  
Resistance Genes ◽  
Powdery Mildew Resistance ◽  
Spring Barley ◽  
Winter Barley ◽  
The Czech Republic ◽  
Mildew Resistance ◽  
Barley Cultivars ◽  
Random Samples

The virulence frequencies to powdery mildew resistance genes possessed by winter barley cultivars registered and newly tested in the Czech Republic were studied in 2000, 2002 and 2004. Random samples of the populations originating from winter and spring barley fields were obtained from the air by a mobile version of a jet spore sampler mounted on a car roof. Conidia were sampled by driving across the Czech Republic. Fourteen differentials, carrying 18 out of 20 currently identified resistance genes present in winter barley cultivars, were used. High virulence frequencies (85–100%) to most resistance genes were found. Lower virulence frequencies (14.1–40.1%) were found to only three resistance genes that have not been described yet; their preliminary designations are Ml(Va), Ml(Dt) and Ml(Ca). The importance of resistance of winter barley cultivars is discussed with respect to limiting the speed with which the pathogen adapts to genetic resistances possessed by commercial cultivars of both winter and spring barley, and to the necessity of lowering the costs for powdery mildew control in barley.

scholarly journals Powdery mildew resistance genes in barley varieties grown in Australia

2012 ◽  
Vol 63 (10) ◽  
pp. 997 ◽  
Author(s):  
Antonín Dreiseitl ◽  
Gregory Platz
Keyword(s):  
Hordeum Vulgare ◽  
Powdery Mildew ◽  
Resistance Genes ◽  
Powdery Mildew Resistance ◽  
Specific Resistance ◽  
Recessive Gene ◽  
Hordeum Vulgare L ◽  
Breeding Programs ◽  
Breeding Lines ◽  
New Varieties

Barley (Hordeum vulgare L.) is a major crop in Australia and powdery mildew (Blumeria graminis f. sp. hordei) is one of its most common diseases. Genes for resistance to powdery mildew were postulated for 86 Australian barley varieties and nine advanced breeding lines using 40 reference isolates of the pathogen. Fifty isolates collected in Australia in 2011 were used for additional tests of some varieties. In total, 22 known resistance genes [mlo, Mla1, MlaAl2, Mla3, Mla6, Mla7, Mla8, Mla9, Mla12, Mla13, Mlat, Mlg, MlGa, Mlk1, MlLa, Mlra, Ml(Ab), Ml(Ch), Ml(Dr2), Ml(He2), Ml(Lo) and Ml(St)] were detected. The most frequent genes were Mla8 and Mlg present in 43 and 34 varieties, respectively, while MlGa was found in 12 varieties. Each of the specific resistance genes Mla1, Mla3, Mla6, Mla9, Mla13, Ml(St) and the non-specific recessive gene mlo was found in one variety only. The varieties Maritime and Stirling appear to carry no specific resistance genes. Fifteen unknown resistances were detected. It is recommended that Australian barley breeding programs exploit European varieties possessing mlo to improve the resistance to powdery mildew in new varieties.

High diversity of powdery mildew resistance in the ICARDA wild barley collection

2017 ◽  
Vol 68 (2) ◽  
pp. 134 ◽  
Author(s):  
Antonín Dreiseitl
Keyword(s):  
Powdery Mildew ◽  
Resistance Gene ◽  
Powdery Mildew Resistance ◽  
Wild Barley ◽  
Agricultural Research ◽  
Specific Resistance ◽  
Durable Resistance ◽  
Barley Cultivars ◽  
The Given ◽  
Pathogenic Diversity

Powdery mildew caused by the fungus Blumeria graminis f. sp. hordei (Bgh) is a global disease of barley, and the wild subspecies Hordeum vulgare subsp. spontaneum (Hvs) is the closest relative of cultivated barley (H. vulgare subsp. vulgare). The responses to the pathogen of 363 Hvs accessions maintained by the International Center for Agricultural Research in the Dry Areas (ICARDA) gene bank were assessed. Thirty non-Israeli pathogen isolates representing the global pathogenic diversity were used for testing. Because of genetic heterogeneity within 146 accessions, the results from only 217 accessions are presented and discussed. Additional tests on 152 accessions with homogeneous responses in earlier tests were made by using six Israeli pathogen isolates. There were 154 resistance phenotypes among the set, 141 of which involved single accessions. The six most frequent phenotypes were recorded for 62 accessions, with the most frequent phenotype in 26 accessions that were resistant to all 30 non-Israeli Bgh isolates. The second most frequent phenotype, found in 16 accessions, was susceptible to all 30 non-Israeli isolates. The occurrence of specific resistance was high. The occurrence of specific resistance was high and for breeding barley cultivars the effective resistances can be combined with the resistance gene mlo. In such combinations, the mlo gene prevents rapid increase in the pathogen population from overcoming the given specific resistance, whereas the resistance gene will simultaneously prevent erosion of mlo resistance. A more effective method for achieving durable resistance is accumulation minor resistance genes that are also widely distributed in wild barley.

Identification and SSR Mapping of Two Powdery Mildew Resistance Genes in Wild Emmer (Triticum dicoccoides) Accessions IW3 and IW10

2009 ◽  
Vol 35 (5) ◽  
pp. 761-767 ◽  
Author(s):  
Gen-Qiao LI ◽  
Ti-Lin FANG ◽  
Hong-Tao ZHANG ◽  
Chao-Jie XIE ◽  
Zuo-Min YANG ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Resistance Genes ◽  
Powdery Mildew Resistance ◽  
Triticum Dicoccoides ◽  
Wild Emmer ◽  
Mildew Resistance

scholarly journals Variety resistance of winter barley to powdery mildew in the field in 1976−2005

2008 ◽  
Vol 43 (No. 3) ◽  
pp. 87-96 ◽  
Author(s):  
A. Dreiseitl
Keyword(s):  
Powdery Mildew ◽  
Disease Severity ◽  
Powdery Mildew Resistance ◽  
Specific Resistance ◽  
Winter Barley ◽  
Mildew Resistance ◽  
Average Resistance ◽  
The Difference ◽  
The Given ◽  
Resistance Of Varieties

The results of evaluation of powdery mildew resistance in winter barley varieties in 285 Czech Official Trials conducted at 20 locations were analysed. Over the period, the number of varieties tested per year increased from four to seven in 1976−1985 to 53−61 in 2002−2005. To assess the resistance of varieties, only trials with sufficient disease severity were used. In 1976−2000, six varieties (1.7% of the varieties tested in the given years) ranked among resistant (average resistance of a variety in a year > 7.5) including NR-468 possessing the gene <i>Mla13</i>, KM-2099 with <i>mlo</i> and Marinka with the genes <i>Mla7</i>, <i>MlaMu2</i>. In 2001−2005, already 33 varieties (16.9%) ranked among resistant, of which Traminer possessing the genes <i>Ml(St)</i> and <i>Ml(IM9 </i> dominated. The proportion of susceptible varieties (average resistance ≤ 5.5) did not change in the two mentioned periods. Two-rowed varieties began to be tested as late as in 1990 (the first variety was Danilo), however, no difference was found in the resistance of two- and six-rowed varieties. Using an example of two pairs of varieties (Dura-Miraj and Marinka-Tiffany) with identical genes for specific resistance but with different resistance in the field, the efficiency of non-specific resistance is discussed. The resistance of domestic and foreign varieties was similar in 1994−2000; however, in 2001−2005 the difference was 0.75 point to disadvantage of domestic ones.

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