089 Inheritance of Powdery Mildew Resistance in Sweet Cherry (Prunus avium L.)

Most sweet cherry (Prunus avium L.) cultivars grown commercially in the Pacific Northwest U.S. are susceptible to powdery mildew caused by the fungus Podosphaera clandestina (Wall.:Fr.) Lev. The disease is prevalent in the irrigated arid region east of the Cascade Mountains in Washington State. Little is known about genetic resistance to powdery mildew in sweet cherry, although a selection (`PMR-1') was identified at the Washington State Unive. Irrigated Agriculture Research and Extension Center that exhibits apparent foliar immunity to the disease. The objective of this research was to characterize the inheritance of powdery mildew resistance from `PMR-1'. Reciprocal crosses between `PMR-1' and three high-quality, widely-grown susceptible cultivars (`Bing', `Rainier', and ëVaní) were made to generate segregating progenies for determining the mode of inheritance of `PMR-1' resistance. Progenies were screened for susceptibility to powdery mildew colonization using a laboratory leaf disk assay. Assay results were verified by natural spread of powdery mildew among the progeny seedlings in a greenhouse and later by placement among infected trees in a cherry orchard. Progenies from these crosses were not significantly different (P > 0.05) when tested for a 1:1 resistant to susceptible segregation ratio, indicating that `PMR-1' resistance is conferred by a single gene, which we propose to designate as PMR-1.

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Inheritance of Powdery Mildew Resistance in Sweet Cherry

HortScience ◽

10.21273/hortsci.36.2.337 ◽

2001 ◽

Vol 36 (2) ◽

pp. 337-340 ◽

Cited By ~ 7

Author(s):

James W. Olmstead ◽

Gregory A. Lang ◽

Gary G. Grove

Keyword(s):

Powdery Mildew ◽

Sweet Cherry ◽

Prunus Avium ◽

Powdery Mildew Resistance ◽

Single Gene ◽

Genetic Resistance ◽

The United States ◽

Washington State ◽

Irrigated Agriculture ◽

Mildew Resistance

Most sweet cherry (Prunus avium L.) cultivars grown commercially in the Pacific Northwestern states of the United States are susceptible to powdery mildew, caused by the fungus Podosphaera clandestina (Wall.:Fr.) Lev. The disease is prevalent in the irrigated arid region east of the Cascade Mountains in Washington State. Little is known about genetic resistance to powdery mildew in sweet cherry, although a selection (PMR-1) was identified at Washington State Univ.'s Irrigated Agriculture Research and Extension Center that exhibits apparent foliar immunity to the disease. The objective of this research was to determine the inheritance of powdery mildew resistance from PMR-1. Reciprocal crosses were made between PMR-1 and three high-quality, widely-grown susceptible cultivars (`Bing', `Rainier', and `Van'). Resultant progenies were screened for reaction to powdery mildew colonization using a laboratory leaf disk assay. Assay results were verified by natural spread of powdery mildew among the progeny in a greenhouse and later by placing them among infected trees in a cherry orchard. Segregation within the progenies for powdery mildew reaction fit a 1 resistant: 1 susceptible segregation ratio (P ≤ 0.05), indicating that resistance to powdery mildew derived from PMR-1 was conferred by a single gene.

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Pmr1, a Gene for Resistance to Powdery Mildew in Sweet Cherry

HortScience ◽

10.21273/hortsci.37.7.1098 ◽

2002 ◽

Vol 37 (7) ◽

pp. 1098-1099 ◽

Cited By ~ 3

Author(s):

James W. Olmstead ◽

Gregory A. Lang

Keyword(s):

Powdery Mildew ◽

Sweet Cherry ◽

Prunus Avium ◽

Powdery Mildew Resistance ◽

Single Gene ◽

The United States ◽

Pedigree Information ◽

Mildew Resistance ◽

Allelic State ◽

Sweet Cherry Cultivars

Most sweet cherry (Prunus avium L.) cultivars grown commercially in the United States are susceptible to powdery mildew, caused by the fungus Podosphaera clandestina (Wall.:Fr.) Lev. Recently, hybrid populations segregating for resistance to powdery mildew were developed by crossing a mildew-resistant sweet cherry selection, PMR-1, with the susceptible cultivars Bing, Rainier, and Van. Although segregation within these populations indicated a single gene was responsible for the powdery mildew resistance conferred by PMR-1, the gene action could not be determined. Therefore, a reciprocal cross between `Bing' and `Van' was made to determine the allelic state of the susceptible parents used previously. All progeny (n = 286) from this cross were susceptible to powdery mildew. This information, combined with results from previous segregation data, indicate the powdery mildew resistance gene is inherited in a dominant manner and is present in PMR-1 in the heterozygous allelic state. We have named this gene Pmr1. Furthermore, in combination with known pedigree information, we have been able to predict the susceptibility of more than 60 additional commercial and recently released sweet cherry cultivars.

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Powdery mildew resistance in soybean PI 243540 is controlled by a single dominant gene

Canadian Journal of Plant Science ◽

10.4141/cjps09070 ◽

2010 ◽

Vol 90 (6) ◽

pp. 939-942 ◽

Cited By ~ 1

Author(s):

S.-T. Kang ◽

M.A. Rouf Mian

Keyword(s):

Powdery Mildew ◽

Powdery Mildew Resistance ◽

Dominant Gene ◽

Genetic Resistance ◽

Segregation Ratio ◽

Common Disease ◽

Growth Stages ◽

Single Dominant Gene ◽

Sources Of Resistance ◽

Mildew Resistance

Powdery mildew (Microsphaera diffusa Cooke & Peck) is a common disease of soybean in many countries of the world, including the northern United States of America and parts of Canada. The genetic resistance of soybean to M. diffusa is known to be controlled by a single locus with three alleles designated as Rmd, Rmd-c and rmd. Identification and characterization of sources of resistance is a prerequisite for the development of resistant cultivars. The objective of this study was to determine the inheritance of powdery mildew resistance in a plant introduction (PI) from Japan, PI 243540. The inheritance of powdery mildew was determined in a segregating population from a cross between powdery mildew susceptible Ohio cultivar Wyandot and PI 243540. The parents and the progeny showed a consistent response to powdery mildew for all growth stages of plants. The two parents, the F1, F2, and F2:3 families from the cross were screened in a greenhouse and field following inoculation with M. diffusa. All F1 plants were resistant to M. diffusa and χ2 analysis for segregation in the population of 343 F2 plants indicated a tight fit for a 3:1 (P = 0.78) ratio, indicative of a single dominant gene. In the next generation, the 334 F2-derived families fit an expected 1 resistant:2 segregating:1 susceptible segregation ratio (P =0.88), which confirmed the results obtained in the F2 generation. Our results indicate that the powdery mildew resistance derived from PI 243540 is controlled by a single dominant gene linked to the Rmd/ Rmd-c/rmd locus. The simple inheritance of this gene should make it relatively easy to find linked DNA markers and transfer the gene to susceptible elite cultivars using the backcross breeding approach.

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Selections from barley landrace collected in Libya as new sources of effective resistance to powdery mildew (Blumeria graminis f.sp. hordei)

Plant Soil and Environment ◽

10.17221/4229-pse ◽

2011 ◽

Vol 48 (No. 5) ◽

pp. 217-223 ◽

Cited By ~ 1

Author(s):

J.H. Czembor ◽

H.J. Czembor

Keyword(s):

Powdery Mildew ◽

Powdery Mildew Resistance ◽

Agricultural Research ◽

Genetic Resistance ◽

Recessive Gene ◽

Blumeria Graminis ◽

Hordeum Vulgare L ◽

Mildew Resistance ◽

Barley Landrace ◽

Barley Powdery Mildew

Powdery mildew on barley (Hordeum vulgare L.) caused by the pathogen Blumeria graminis f.sp. hordei occurs worldwide and can result in severe yield loss. Because agronomical methods to control the disease are not completely effective, cultivars with genetic resistance are needed. Therefore, there is a need to describe new sources of genes that confer resistance to barley powdery mildew. This study was conducted to determine the genetic basis of resistance to powdery mildew in three selections 995-1-1, 995-1-2, 995-1-3 from barley landrace 995 (ICB 112840) collected in Al Aziziyah district, Tripolitania, Libya. Landrace originated from InternationalCenter for Agricultural Research in the Dry Areas – ICARDA, Aleppo, Syria. To determine the number of genes, the types of genes action and the gene loci in tested lines two types of crosses were made: (1) the lines were crossed to the susceptible cultivar Pallas, (2) the lines were crossed with Pallas isoline P22 carrying gene mlo5. The parents and progeny F2 were evaluated with isolate R303.1 for the powdery mildew resistance. Based on segregation ratios we found that resistance in these three selections was determined by a single recessive gene allelic to the Mlo locus occurring in Pallas isoline P22. In addition tested lines showed resistance reaction type 0(4) characteristic only for genes mlo. The value of new identified sources of highly effective powdery mildew resistance to breeding programs and barley production is discussed.

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Powdery Mildew Resistance in Wheat Cultivar Mv Hombár is Conferred by a New Gene, PmHo

Phytopathology ◽

10.1094/phyto-03-16-0152-r ◽

2016 ◽

Vol 106 (11) ◽

pp. 1326-1334

Author(s):

Judit Komáromi ◽

Tünde Jankovics ◽

Attila Fábián ◽

Katalin Puskás ◽

Zengyan Zhang ◽

...

Keyword(s):

Powdery Mildew ◽

Resistance Gene ◽

Powdery Mildew Resistance ◽

Recombinant Inbred Lines ◽

Fungal Growth ◽

Segregation Ratio ◽

Colony Development ◽

Powdery Mildew Resistance Gene ◽

Mildew Resistance ◽

Microscopic Studies

A new powdery mildew resistance gene designated as PmHo was identified in ‘Mv Hombár’ winter wheat, bred in Martonvásár, Hungary. It has exhibited a high level of resistance over the last two decades. Genetic mapping of recombinant inbred lines derived from the cross ‘Ukrainka’/Mv Hombár located this gene on chromosome 2AL. The segregation ratio and consistent effect in all environments indicated that PmHo is a major dominant powdery mildew resistance gene. The race-specific nature of resistance in Mv Hombár was shown by the emergence of a single virulent pathotype designated as 51-Ho. This pathotype was, to some extent, able to infect Mv Hombár, developing visible symptoms with sporulating colonies. Microscopic studies revealed that, in incompatible interactions, posthaustorial hypersensitivity reaction was the most prevalent but not exclusive plant defense response in Mv Hombár, and fungal growth was mostly arrested during haustorium formation or in the early stages of colony development. The delayed fungal development of the virulent pathotype 51-Ho may be explained by additional effects of other loci that were also involved in the powdery mildew resistance of Mv Hombár.

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Characterization of a Segregation Distortion Locus with Powdery Mildew Resistance in a Wheat-Thinopyrum intermedium Introgression Line WE99

Plant Disease ◽

10.1094/pdis-11-15-1352-re ◽

2016 ◽

Vol 100 (8) ◽

pp. 1541-1547 ◽

Cited By ~ 2

Author(s):

Pengtao Ma ◽

Hongxing Xu ◽

Guohao Han ◽

Qiaoling Luo ◽

Yunfeng Xu ◽

...

Keyword(s):

Powdery Mildew ◽

Powdery Mildew Resistance ◽

Single Gene ◽

Introgression Line ◽

Triticum Aestivum L ◽

Thinopyrum Intermedium ◽

Seedling Resistance ◽

Mildew Resistance ◽

Genotype Frequencies ◽

Chromosome Arm

Exploitation of host resistance is important for controlling powdery mildew of wheat (Triticum aestivum L.). In this study, a wheat-Thinopyrum intermedium introgression line, designated WE99, conferred seedling resistance to 47 of 49 Blumeria graminis f. sp. tritici isolates. Genetic analysis demonstrated that the resistance segregation deviated significantly from a single gene Mendelian ratio. However, marker analysis indicated that only a single recessive resistance gene, temporarily designated PmWE99, conferred powdery mildew resistance (Pm). PmWE99 was mapped to chromosome arm 2BS and linked to the three simple-sequence repeat markers Gwm148, Gwm271, and Barc55. Using race spectrum analysis, PmWE99 was shown to be significantly different from the documented genes Pm42 and MlIW170 located on chromosome arm 2BS and, thus, appeared to be a new Pm gene. Examination of the genotype frequencies in the F2:3 families showed that a genetic variation in the PmWE99 interval that favored the transmission of the WE99 allele could be the cause of the deviated segregation. Further investigation revealed that the abnormal segregation only occurred at the PmWE99 interval and was not common at other loci in this population. Identification of PmWE99 will increase the diversity of the Pm genes for wheat improvement.

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Genetics of Resistance to Wheat Leaf Rust, Stem Rust, and Powdery Mildew in Aegilops sharonensis

Phytopathology ◽

10.1094/phyto-98-3-0353 ◽

2008 ◽

Vol 98 (3) ◽

pp. 353-358 ◽

Cited By ~ 12

Author(s):

P. D. Olivera ◽

E. Millet ◽

Y. Anikster ◽

B. J. Steffenson

Keyword(s):

Powdery Mildew ◽

Leaf Rust ◽

Stem Rust ◽

Powdery Mildew Resistance ◽

Single Gene ◽

Adult Plant ◽

Mildew Resistance ◽

Aegilops Sharonensis ◽

Plant Stage ◽

Allelism Tests

Aegilops sharonensis (Sharon goatgrass) is a wild relative of wheat and a rich source of genetic diversity for disease resistance. The objectives of this study were to determine the genetic basis of leaf rust, stem rust, and powdery mildew resistance in A. sharonensis and also the allelic relationships between genes controlling resistance to each disease. Progeny from crosses between resistant and susceptible accessions were evaluated for their disease reaction at the seedling and/or adult plant stage to determine the number and action of genes conferring resistance. Two different genes conferring resistance to leaf rust races THBJ and BBBB were identified in accessions 1644 and 603. For stem rust, the same single gene was found to confer resistance to race TTTT in accessions 1644 and 2229. Resistance to stem rust race TPMK was conferred by two genes in accessions 1644 and 603. A contingency test revealed no association between genes conferring resistance to leaf rust race THBJ and stem rust race TTTT or between genes conferring resistance to stem rust race TTTT and powdery mildew isolate UM06-01, indicating that the respective resistance genes are not linked. Three accessions (1644, 2229, and 1193) were found to carry a single gene for resistance to powdery mildew. Allelism tests revealed that the resistance gene in accession 1644 is different from the respective single genes present in either 2229 or 1193. The simple inheritance of leaf rust, stem rust, and powdery mildew resistance in A. sharonensis should simplify the transfer of resistance to wheat in wide crosses.

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