DNA MARKING WHEN CREATING APPLE VARIETIES WITH STABLE SCAB RESISTANCE

2020 ◽  
pp. 94-99
Author(s):  
М.I. Dulov ◽  
Keyword(s):  
Resistance Genes ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
Genetic Resistance ◽  
Scab Resistance ◽  
Apple Breeding ◽  
Apple Varieties ◽  
Pcr Product ◽  
Fruit Flavor ◽  
New Generation

The use of chemical means of protection against Apple scab is associated with high material costs and causes great harm to the environment. Growing of apple varieties with stable resistance to scab (the pathogen Venturia inaequalis) will significantly limit the use of pesticides. On the territory of the Russian Federation, the Rvi6 gene is considered immune, which determines resistance to five scab races, including the most aggressive fifth. The country has scabimmune apple varieties created by scientists from VNIISPK, NCFSCHWWG, FRC named after I. V. Michurin , VSTISP and other scientific institutions. In recent years, the Rvi6 gene has been overcome by scab in many European countries, and the Rvi5 gene, which is immune to four scab races, has been overcome in Russia and Germany. When creating high-yielding apple varieties of a new generation, with good fruit flavor quality, long-term and stable resistance to scab, in addition to the rvi6 resistance gene, the most promising sources are the Rvi5, Rvi11, Rvi12, Rvi14 and Rvi15 genes. The Rvi2, Rvi4, Rvi6, Rvi7 and Rvi9 genes in the apple breeding process are best used in extended pyramids of genetic resistance to scab. This will allow you to combine several scab resistance genes that control the immune system in one apple genotype. The article describes the characteristics of DNA markers, the nucleotide sequence of primers, the size of target fragments of the PCR product, including the size of the dominant allele product for detecting Rvi genes of the Venturia inaequalis pathogen that are promising for apple breeding in varieties and hybrid material. Amplification programs were selected to identify resistance genes to various races of apple scab.

scholarly journals Field apple scab susceptibility of a diverse Malus germplasm collection identifies potential sources of resistance for apple breeding

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
David Papp ◽  
Liqiang Gao ◽  
Ranjita Thapa ◽  
Dan Olmstead ◽  
Awais Khan
Keyword(s):  
New York ◽  
Resistance Genes ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
Genetic Research ◽  
Germplasm Collection ◽  
Resistance Breeding ◽  
Scab Resistance ◽  
Sources Of Resistance ◽  
Apple Breeding

Abstract Background Breeding for resistance to apple scab (caused by Venturia inaequalis), the most devastating fungal disease of apples, relies on genetic resources maintained in germplasm collections. Methods To identify new sources of scab resistance, we evaluated 177 Malus accessions, including 27 primary and 13 hybrid Malus species from diverse geographical origins, in an orchard at Geneva, New York. We also screened a differential host set for 2 years to monitor for changes in the effectiveness of ten known scab resistance genes, which allowed us to confirm the presence of virulent pathogen races in the orchard. Results We found that ~ 37% of the wild Malus accessions and domesticated cultivars were resistant to apple scab in the field. Several of these accessions were unrelated to sources of previously known resistance genes and are promising for apple scab genetic research and resistance breeding. Cultivars carrying the Rvi6 (Vf) gene from Malus floribunda clone 821, e.g. ‘Liberty’ or ‘Florina’, remained resistant despite the breakdown of Rvi6. ‘Demir’, a Malus hybrid from Turkey, and ‘Chisel Jersey’, a traditional English hard cider cultivar, showed fewer symptoms than the Rvi6 resistant cultivar ‘Prima’. Races 1 to 7 and 9 of V. inaequalis were present in the orchard, but no scab was observed on the indicator host accessions for races 11 and 12. Conclusions Detailed and systematic screening of Malus germplasm identified resistant and moderately resistant donor accessions based on resistance reaction types. These accessions are promising for use in future genetic studies to identify novel sources of scab resistance alleles for apple breeding to develop cultivars with durable apple scab resistance.

scholarly journals Quantitative Trait Loci (QTL) Analysis Reveals Both Broad-Spectrum and Isolate-Specific QTL for Scab Resistance in an Apple Progeny Challenged with Eight Isolates of Venturia inaequalis

2004 ◽  
Vol 94 (4) ◽  
pp. 370-379 ◽  
Author(s):  
F. Calenge ◽  
A. Faure ◽  
M. Goerre ◽  
C. Gebhardt ◽  
W. E. Van de Weg ◽  
...  
Keyword(s):  
Quantitative Trait Loci ◽  
Resistance Gene ◽  
Resistance Genes ◽  
Quantitative Trait ◽  
Venturia Inaequalis ◽  
Scab Resistance ◽  
Breeding Programs ◽  
Apple Breeding ◽  
Trait Loci ◽  
New Races

The major scab resistance gene Vf, extensively used in apple breeding programs, was recently overcome by the new races 6 and 7 of the fungal pathogen Venturia inaequalis. New, more durable, scab resistance genes are needed in apple breeding programs. F1 progeny derived from the cross between partially resistant apple cv. Discovery and apple hybrid ‘TN10-8’ were inoculated in the greenhouse with eight isolates of V. inaequalis, including isolates able to overcome Vf. One major resistance gene, Vg, and seven quantitative trait loci (QTL) were identified for resistance to these isolates. Three QTL on linkage group (LG)12, LG13, and LG15 were clearly isolate-specific. Another QTL on LG5 was detected with two isolates. Three QTL on LG1, LG2, and LG17 were identified with most isolates tested, but not with every isolate. The QTL on LG2 displayed alleles conferring different specificities. This QTL co-localized with the major scab resistance genes Vr and Vh8, whereas the QTL on LG1 colocalized with Vf. These results contribute to a better understanding of the genetic basis of the V. inaequalis-Malus × domestica interaction.

scholarly journals Molecular Markers for the Scab Resistance (Vf) Region in Apple

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 855C-855 ◽  
Author(s):  
Minou Hemmat ◽  
Norman F. Weeden ◽  
Susan K. Brown
Keyword(s):  
Molecular Markers ◽  
Bulk Segregant Analysis ◽  
Rapd Markers ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
Genetic Resistance ◽  
Scab Resistance ◽  
Tight Linkage ◽  
Commercially Important ◽  
The Relationship

Apple scab, Venturia inaequalis (Cke.) Wint., is one of the most damaging diseases of apples. Although fungicide sprays have been used to control the disease, genetic resistance in existing commercially important varieties would be desirable. Identification of molecular marker(s) would be helpful in devising biotechnological approaches to control the disease. We used bulk segregant analysis to identify RAPD markers that cosegregate or display a tight linkage with Vf gene in Prima × Spartan cross. Using this approach, we are saturating the region around the scab resistance gene for the purpose of bracketing the locus. We have identified several markers associated with the Vf locus. The closest markers have been isolated and sequenced to be used as SCARs. The relationship and distances of the markers with the Vf locus and other previously reported markers will be discussed.

scholarly journals Molecular screening of domestic apple cultivars for scab resistance genes in Greece

2020 ◽  
Vol 56 (No. 4) ◽  
pp. 165-169
Author(s):  
Lefkothea Karapetsi ◽  
Irini Nianiou-Obeidat ◽  
Antonios Zambounis ◽  
Maslin Osathanunkul ◽  
Panagiotis Madesis
Keyword(s):  
Resistance Genes ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
Scab Resistance ◽  
Molecular Screening ◽  
Polygenic Resistance ◽  
Main Target ◽  
Efficient Control ◽  
Apple Cultivars ◽  
Efficient Breeding

Apple scab caused by Venturia inaequalis has the most destructive effects among other phytopathogens in apple crops all over the world. The integration of resistance genes from local and domestic cultivars is a prerequisite for the efficient control of this disease and is a main target in efficient breeding approaches. Across Greece, many domestic apple cultivars are reported without deep knowledge about the presence and diversity of scab resistance genes. In this study, the presence of five resistance genes (Rvi2, Rvi4, Rvi6, Rvi8 and Rvi11) was evaluated across twenty local and domestic apple genotypes, employing twelve molecular markers closely linked to known apple scab resistance loci. Significant differences and polymorphisms among the tested cultivars were detected suggesting that some of them carry a sufficient number of resistance genes. This observed genetic diversity could be exploited in ongoing breeding approaches as a natural source of polygenic resistance against apple scab.

scholarly journals Ten Years of VINQUEST: First Insight for Breeding New Apple Cultivars With Durable Apple Scab Resistance

Plant Disease ◽  
2020 ◽  
Vol 104 (8) ◽  
pp. 2074-2081 ◽  
Author(s):  
Andrea Patocchi ◽  
Andreas Wehrli ◽  
Pierre-Henri Dubuis ◽  
Annemarie Auwerkerken ◽  
Carmen Leida ◽  
...  
Keyword(s):  
Resistance Genes ◽  
Venturia Inaequalis ◽  
Durable Resistance ◽  
Apple Scab ◽  
Resistance Breeding ◽  
Scab Resistance ◽  
Data Points ◽  
Resistance Breakdown ◽  
Apple Cultivars ◽  
Apple Production

Apple scab, caused by Venturia inaequalis, is a major fungal disease worldwide. Cultivation of scab-resistant cultivars would reduce the chemical footprint of apple production. However, new apple cultivars carrying durable resistances should be developed to prevent or at least slow the breakdown of resistance against races of V. inaequalis. One way to achieve durable resistance is to pyramid multiple scab resistance genes in a cultivar. The choice of the resistance genes to be combined in the pyramids should take into account the frequency of resistance breakdown and the geographical distribution of apple scab isolates able to cause such breakdowns. In order to acquire this information and to make it available to apple breeders, the VINQUEST project ( www.vinquest.ch ) was initiated in 2009. Ten years after launching this project, 24 partners from 14 countries regularly contribute data. From 2009 to 2018, nearly 9,000 data points have been collected. This information has been used to identify the most promising apple scab resistance genes for developing cultivars with durable resistance, which to date are: Rvi5, Rvi11, Rvi12, Rvi14, and Rvi15. As expected, Rvi1, together with Rvi3 and Rvi8, were often overcome, and have little value for scab resistance breeding. Rvi10 may also belong to this group. On the other hand, Rvi2, Rvi4, Rvi6, Rvi7, Rvi9, and Rvi13 are still useful for breeding, but their use is recommended only in extended pyramids of ≥3 resistance genes.

scholarly journals MOLECULAR SCREENING OF SOME ROMANIAN APPLE CULTIVARS FOR SCAB RESISTANCE GENES

2020 ◽  
Vol 36 ◽  
pp. 5-11
Author(s):  
Mădălina Militaru ◽  
Monica Sturzeanu ◽  
Adina Iancu
Keyword(s):  
Molecular Markers ◽  
Resistance Genes ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
Scab Resistance ◽  
Research Station ◽  
Breeding Center ◽  
Fruit Growing ◽  
Apple Cultivars ◽  
Almost All

Apple scab, incided by the fungus Venturia inaequalis (Cke.) Wint., is a devastating disease of apple reported from almost all apple producing Romanian areas, which causes up to 70% losses of production. Molecular markers were used for detection of scab resistance genes in 22 old and introduced apple cultivars ('Romus 3', 'Romus 5', 'Rebra', 'Rustic', 'Nicol', 'Colmar', 'Colonade', registered by Research Institute for Fruit Growing Pitesti; 'Generos', 'Iris', 'Irisem', 'Luca', 'Ciprian', 'Cezar', 'Remar', 'Valery', 'Real', registered by Research Station for Fruit Growing Voinesti, Dambovita; 'Aura', 'Starkprim', 'Ionaprim', 'Bistritean', registered by Research Station for Fruit Growing Bistrita and old cultivars: 'Domnesc', 'Cretesc'). The presence of scab resistance genes were detected using the molecular markers: AL-07 (SCAR), AM19 (SCAR), VfC for Rvi6 (Vf) gene, AD13 (SCAR) for Rvi4 (Vr1) gene, OPL19 (SCAR) for Rvi2 (Vh2) and Rvi8 (Vh8) genes and OPB12 (STS) for Rvi5 (Vm) gene. The Rvi6 gene was detected in 17 cultivars from different breeding center. The marker AD13 presents in genome of 8 cultivars, such as 'Romus 3', 'Romus 5', 'Generos', 'Iris', 'Irisem', 'Cezar', 'Remar', 'Aura'. The Rvi5 gene was revealed in 3 cultivars ('Nicol', 'Generos', 'Irisem'), only.

scholarly journals Identification of apple scab and powdery mildew resistance genes in Czech apple (Malus × domestica) genetic resources by PCR molecular markers

2011 ◽  
Vol 47 (No. 4) ◽  
pp. 156-165 ◽  
Author(s):  
J. Patzak ◽  
F. Paprštein ◽  
A. Henychová
Keyword(s):  
Molecular Markers ◽  
Powdery Mildew ◽  
Genetic Resources ◽  
Resistance Genes ◽  
Powdery Mildew Resistance ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
Scab Resistance ◽  
Mildew Resistance ◽  
Apple Cultivars

The presence of genes for resistance to scab (Venturia inaequalis) and powdery mildew (Podosphaera leucotricha) was studied using molecular markers in a sample of 279 apple cultivars from the Czech collection of apple genetic resources. The sample comprised 37 cultivars supposed to have the Vf gene for scab resistance, 97 reference world cultivars and 145 old and local cultivars. Six PCR molecular markers for the scab resistance genes Vf, Vm, Vbj, Vr and Vh and three PCR molecular markers for the powdery mildew resistance genes Pl-w, Pl-1 and Pl-d were used. The marker for the major scab resistance gene Vf was detected in all cultivars supposed to have Vf, except in Romus 1, and in the three small-fruited cultivars Malus Evereste, Golden Gem and Hilleri. The markers of the Vr and Vh scab resistance genes were detected in 22 cultivars in combination with the marker for Vf, in 56 reference world cultivars and in 82 old and local apple cultivars. PCR molecular markers for one or two of the powdery mildew resistance genes were detected in the small-fruited cultivars Malus Evereste, Golden Gem, prof. Sprengeri and Hilleri; and in the larger fruited cultivars Hagloe Crab, Borovinka and Tita Zetei. We did not find markers for the scab resistance genes Vm and Vbj in any of the studied cultivars. They are absent also in the remaining part of the Czech collection of apple genetic resources. PCR molecular markers are useful tools for the identification of resistance genes within apple germplasm collections and can be used to increase the number of sources for disease resistance in breeding programmes.

scholarly journals Virulence Characterization of Venturia inaequalis Reference Isolates on the Differential Set of Malus Hosts

Plant Disease ◽  
2015 ◽  
Vol 99 (3) ◽  
pp. 370-375 ◽  
Author(s):  
Valérie Caffier ◽  
Andrea Patocchi ◽  
Pascale Expert ◽  
Marie-Noëlle Bellanger ◽  
Charles-Eric Durel ◽  
...  
Keyword(s):  
Resistance Gene ◽  
Resistance Genes ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
Scab Resistance ◽  
Reference Set ◽  
Major Resistance Gene ◽  
Differential Hosts ◽  
Major Resistance Genes

A set of differential hosts has recently been identified for 17 apple scab resistance genes in an updated system for defining gene-for-gene (GfG) relationships in the Venturia inaequalis-Malus pathosystem. However, a set of reference isolates characterized for their complementary avirulence alleles is not yet available. In this paper, we report on improving the set of differential hosts for h(7) and propose the apple genotype LPG3-29 as carrying the single major resistance gene Rvi7. We characterized a reference set of 23 V. inaequalis isolates on 14 differential apple hosts carrying major resistance genes under controlled conditions. We identified isolates that were virulent on at least one of the following defined resistance gene hosts: h(1), h(2), h(3), h(4), h(5), h(6), h(7), h(8), h(9), h(10), and h(13). Sixteen different virulence patterns were observed. In general, the isolates carried one to three virulences, but some of them were more complex, with up to six virulences. This set of well-characterized isolates will be helpful for the identification of additional apple scab resistance genes in apple germplasm and the characterization of new GfG relationships to help improve our understanding of the host-pathogen interactions in the V. inaequalis-Malus pathosystem.

scholarly journals Tagging and Mapping Scab Resistance Genes from R12740-7A Apple

2002 ◽  
Vol 127 (3) ◽  
pp. 365-370 ◽  
Author(s):  
Minou Hemmat ◽  
Susan K. Brown ◽  
Norman F. Weeden
Keyword(s):  
Resistance Genes ◽  
Genetic Basis ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
Scab Resistance ◽  
Apple Seedling ◽  
Foliar Resistance ◽  
Segregation Ratios ◽  
Chlorotic Lesion ◽  
Dominant Genes

The genetic basis of resistance to apple scab [Venturia inaequalis (Cke.) Wint.] in the Russian apple seedling R12740-7A (Malus Mill. sp.) was investigated. Segregation ratios obtained in crosses with susceptible cultivars suggested that at least two genes were involved, and three foliar resistance reactions (chlorotic, stellate necrotic, and pit type) were observed after inoculation. DNA markers were identified for both the stellate necrotic (Vr) and pit type (no locus designation, Vx suggested) resistance phenotypes. Comparison of resistance phenotypes with marker segregation demonstrated that only two major dominant genes were present in R12740-7A, one producing the stellate necrotic lesion and the other the pit-type lesion. The chlorotic lesion could be attributed to either unclear expression of the resistance phenotype or to susceptible genotypes not contracting the disease. These markers along with a previously published marker for Vf were used to analyze inheritance of resistance in a Vr × Vf cross in advanced breeding material. The markers identified successfully all susceptible progeny, as well as apparent escapes and individuals possessing both Vf and Vr. Thus, the markers should be useful in future screening of segregating progeny and in the pyramiding of scab resistance genes in new cultivars.

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