scholarly journals FIELD EVIDENCE FOR A NEW RACE OF POWDERY MILDEW ON MELON

HortScience ◽  
2005 ◽  
Vol 40 (3) ◽  
pp. 888a-888 ◽  
Author(s):  
James D. McCreight ◽  
Michael D. Coffey ◽  
Thomas A. Turini ◽  
Michael E. Matheron
Keyword(s):  
Powdery Mildew ◽  
Powdery Mildew Resistance ◽  
Genetic Resistance ◽  
Podosphaera Xanthii ◽  
Sphaerotheca Fuliginea ◽  
Imperial Valley ◽  
Field Evidence ◽  
Race 1 ◽  
New Race ◽  
The U.S

Races 1 and 2 of Podosphaera xanthii (syn. Sphaerotheca fuliginea) were defined in Imperial Valley, Calif. 1938 when P. xanthii overcame genetic resistance in `PMR 45'. Race 3 was first observed in the U.S. in 1976 in Texas; 15 additional races of P. xanthii have been reported in the literature since 1996. Races 1 and 2 have been common in Arizona and California based upon the effectiveness of the powdery mildew resistance genes in commercially available melon cultivars grown in these states. Field data from 11 commonly used melon P. xanthii race differentials in 2001 and 2002 indicated the presence of race 1 in the Imperial Valley and San Joaquin Valley of California, and Yuma, Arizona. In spring 2003, the powdery mildew race situation changed. The first evidence was the occurrence of a severe and widespread infection of powdery mildew in a commercial cantaloupe field. The 11 powdery mildew race differentials were susceptible to powdery mildew in a nearby replicated field test. PI 313970, a melon from India, was resistant to this apparent new race of powdery mildew.

scholarly journals Genes for Resistance to Powdery Mildew Races 1 and 2U.S. in Melon PI 313970

HortScience ◽  
2003 ◽  
Vol 38 (4) ◽  
pp. 591-594 ◽  
Author(s):  
James D. McCreight
Keyword(s):  
Powdery Mildew ◽  
Cucumis Melo ◽  
Powdery Mildew Resistance ◽  
Dominant Gene ◽  
Recessive Gene ◽  
Sphaerotheca Fuliginea ◽  
Limited Data ◽  
Race 1 ◽  
Resistance Reaction ◽  
Greenhouse Tests

Powdery mildew is a major problem in melon (Cucumis melo L.) production worldwide. Three genes for resistance to Sphaerotheca fuliginea (Schlecht. ex Fr.) Poll. race 1 and race 2U.S. were identified in growth chamber and greenhouse tests in the cross of PI 313970 × `Top Mark'. A recessive gene conditioned resistance of true leaves to race 1. A recessive gene appeared to condition resistance of cotyledons to race 2U.S., although a second recessive gene may be involved. A semi-dominant gene conditioned resistance of true leaves to race 2U.S. Limited data suggested linkage of the recessive gene for resistance to race 1 and the semi-dominant gene for resistance to race 2U.S. The resistance reaction of PI 313970 to infection of true leaves by race 2U.S. included water-soaked spots and resistant blisters, but segregation data for the resistant blister reaction were inconclusive. Allelic relationships of these genes with previously reported melon powdery mildew resistance genes remain to be determined.

scholarly journals Melon-Powdery Mildew Interactions Reveal Variation in Melon Cultigens and Podosphaera xanthii Races 1 and 2

2006 ◽  
Vol 131 (1) ◽  
pp. 59-65 ◽  
Author(s):  
James D. McCreight
Keyword(s):  
Powdery Mildew ◽  
Virulence Factors ◽  
Cucumis Melo ◽  
Podosphaera Xanthii ◽  
Sphaerotheca Fuliginea ◽  
Race 1 ◽  
New Races ◽  
Race 2 ◽  
Serious Disease ◽  
Greenhouse Tests

Powdery mildew is a serious disease of melon (Cucumis melo L.) worldwide. Twenty-two melon cultigens have been used to define 22 reported races of the pathogen Podosphaera xanthii (sect. Sphaerotheca) xanthii (Castag.) U. Braun & N. Shish. Comb. nov. [syn. Sphaerotheca fuliginea (Schlecht. ex Fr.) Poll.]. Discrepancies in the reactions of eight cultigens to populations of P. xanthii races 1 and 2 in California, Japan, and Spain revealed genetic differences among them that can be used to differentiate P. xanthii race 1 and 2 populations in these countries. Implicit in these results is the existence of previously unknown virulence factors in these populations of P. xanthii races 1 and 2 that permit designation of new races of P. xanthii on melon. Synthesis of these results with previous reports resulted in the identification of 28 putative races of P. xanthii on melon that include eight variants of race 1 and six variants of race 2. Six of the cultigens exhibited resistant blisters in response to heavy infection by P. xanthii in field and greenhouse tests.

Molecular Markers for Powdery Mildew in Pea (Pisum sativum L.): A Review

2021 ◽  
Author(s):  
Reginah Pheirim ◽  
Noren Singh Konjengbam ◽  
Mayurakshee Mahanta
Keyword(s):  
Disease Resistance ◽  
Powdery Mildew ◽  
Powdery Mildew Resistance ◽  
Genetic Resistance ◽  
Disease Resistance Gene ◽  
Breeding Programs ◽  
Biotic Stresses ◽  
Pisum Sativum L ◽  
Development And Utilization ◽  
Mapping Populations

Powdery mildew is caused by an obligate parasite Erysiphe pisi and considered as one of the most important constraints causing yield reductions in pea. Development and utilization of genetic resistance is acknowledged as the most effective, economic and environmental friendly method of control. Therefore, development of cultivars with improved resistance to biotic stresses is a primary goal of plant breeding programs throughout the world. Three monogenic sources er1, er2 and Er3 have been described to govern the powdery mildew disease resistance. Several markers have been reported linked to resistant genes at varying distances in different mapping populations. Genetic markers linked to the disease resistance gene make the breeding process more efficient for the use of Marker Assisted Selection (MAS) strategy to aid in obtaining a complete powdery mildew resistance in pea.

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

HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 404A-404
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 ◽  
Segregation Ratio ◽  
Washington State ◽  
Irrigated Agriculture ◽  
Mildew Resistance

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.

scholarly journals Occurrence of Powdery Mildew Caused by New Race 2F of Podosphaera xanthii on Cucumber in Korea

2020 ◽  
Vol 26 (3) ◽  
pp. 183-189
Author(s):  
Young-Ah Kim ◽  
A-Ram Jeong ◽  
Min Jang ◽  
Chang-Jin Park
Keyword(s):  
Powdery Mildew ◽  
Podosphaera Xanthii ◽  
New Race

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

2011 ◽  
Vol 48 (No. 5) ◽  
pp. 217-223 ◽  
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.

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 First report of powdery mildew caused by Podosphaera xanthii race 1 on watermelon in China

2021 ◽  
Author(s):  
Haonan Cui ◽  
Zicheng Zhu ◽  
Zhuo Ding ◽  
Yuanzuo Lv ◽  
Lei Sun ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Podosphaera Xanthii ◽  
First Report ◽  
Race 1

scholarly journals Evaluation of Watermelon and Related Species for Resistance to Race 1W Powdery Mildew

2007 ◽  
Vol 132 (6) ◽  
pp. 790-795 ◽  
Author(s):  
Angela R. Davis ◽  
Amnon Levi ◽  
Antonia Tetteh ◽  
Todd Wehner ◽  
Vincent Russo ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Citrullus Lanatus ◽  
Plant Introduction ◽  
The United States ◽  
Common Disease ◽  
Podosphaera Xanthii ◽  
Sphaerotheca Fuliginea ◽  
Wild Type ◽  
Intermediate Resistance ◽  
Cultivated Species

Powdery mildew [Podosphaera xanthii (Castagne) Braun & Shishkoff (syn. Sphaerotheca fuliginea auct. p.p.)] is now a common disease on watermelon [Citrullus lanatus (Thunb.) Matsum. & Nakai] in the United States. In this study, the entire available U.S. Plant Introduction collection of Citrullus Schrad. ex Eckl. & Zeyh. species was evaluated for resistance to P. xanthii race 1W. The collection consists of four Citrullus species and one Praecitrullus Pangalo species [C. lanatus var. citroides (L.H. Bailey) Mansf., C. colocynthis (L.) Schrad., C. rehmii De Winter, and P. fistulosus (Stocks) Pangalo]. Wild-type accessions tended to be more resistant more often than the cultivated species, C. lanatus var. lanatus. None were immune, eight of the 1573 accessions exhibited high levels of resistance, and another 86 demonstrated intermediate resistance. Stem and leaf disease severity were weakly correlated (r 2 = 0.64, P = 0.001). The majority of accessions having resistance were collected in Zimbabwe. Resistance was found in four species.

scholarly journals Reaction of families and lines of melon to powdery mildew

2011 ◽  
Vol 29 (3) ◽  
pp. 382-386 ◽  
Author(s):  
Rui Sales Júnior ◽  
Glauber HS Nunes ◽  
Sami J Michereff ◽  
Elaíne WL Pereira ◽  
Izabel M Guimarães
Keyword(s):  
Powdery Mildew ◽  
Genetic Variability ◽  
Podosphaera Xanthii ◽  
Severity Scale ◽  
Simple Lattice ◽  
Randomized Design ◽  
Race 1 ◽  
Completely Randomized Design ◽  
Brazilian Northeast ◽  
Important Disease

Powdery mildew, caused by Podosphaera xanthii, is an important disease of melon in the Brazilian Northeast. The objective of this work was to evaluate the reaction of families, lines and cultivars of melon to P. xanthii. Two experiments in simple lattice were carried out under field conditions in the municipalities of Mossoró and Baraúna to evaluate 144 families. In a greenhouse, an experiment was carried out in a completely randomized design to evaluate 19 lines and the cultivars Yellow Queen, Chilton and Hy Mark. Disease was assessed by a severity scale. There was genetic variability among families. The families 4, 5, 11, 14, 18, 23, 33, 42, 101, 112 and 140 were identified in both sites as resistant. The lines LOF-027, LOF-105, LPS-124, MEL-008 and cultivar Chilton showed resistance to race 1 of the fungus.

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