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 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 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 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 Farm-scale evaluation of two widely used sanitation practices for reducing primary inoculums of apple scab in organic apple production

2013 ◽  
Vol 19 (3-4) ◽  
Author(s):  
I. J. Holb ◽  
A. Rózsa ◽  
F. Abonyi
Keyword(s):  
Primary Infection ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
Apple Orchard ◽  
Scale Level ◽  
Scale Evaluation ◽  
Farm Scale ◽  
Apple Cultivars ◽  
Apple Production ◽  
Fallen Leaves

Effects of two widely used sanitation practices were evaluated at farm-scale level on leaf degradation and primary infection by Venturia inaequalis in an organic apple orchard (Eperjeske) on two apple cultivars (Jonathan and Prima) from 2011 to 2013. The tested sanitation practices were eradication of fallen leaves by collection and disc cultivation. Treatments of eradication of fallen leaves by collection and disc cultivation reduced signifi cantly (P< 0.001) leaf litter density with 70–85 and 40–55%, respectively, compared to untreated plots in both years. Above treatments in the same order reduced spring scab incidence with 40–50, and 10–20%, respectively, compared to untreated plots. Incidence of leaf scab in autumn was not signifi cantly lower (P< 0.05) in the treatments in the years.

scholarly journals A Molecular Marker Linked to a Scab Resistance Gene (Vf) in Apple

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 619a-619
Author(s):  
Hong Y. Yang ◽  
Schuyler S. Korban ◽  
Jutta Kruger ◽  
Hanna Schmidt
Keyword(s):  
Resistance Gene ◽  
Venturia Inaequalis ◽  
Dominant Gene ◽  
Apple Scab ◽  
Scab Resistance ◽  
Polymorphism Analysis ◽  
Recurrent Parent ◽  
Specific Primers ◽  
Apple Cultivars ◽  
Donor Parent

Apple scab, caused by Venturia inaequalis (Cke.) Wint., is the most serious disease of apple trees. Resistance to V. inaequalis, derived from the small-fruited species Malus floribunda 821, is determined by a major dominant gene Vf. Our major objective is to identify RAPD markers linked to the Vf gene. The approach in this paper is based on the introgression of the Vf gene from M. floribunda into commercial cultivars. Almost 200 random sequence decamer-primers have been used to screen a pair of bulked samples and the donor parent M. floribunda clone 821 for markers linked to the Vf gene conferring resistance to apple scab. A single primer has been identified which generated a PCR fragment, OPK16/1300, from the donor parent M. floribunda clone 821 and the scab-resistant selections/cultivars bulk, but not from the scab-susceptible recurrent parent bulk. Co-segregation analysis using a segregating apple progeny and polymorphism analysis of individual scab-resistant Coop selections/cultivars have confirmed that this marker is linked to the scab-resistance gene Vf. OPK16/1300 has since been cloned and sequenced. Sequence-specific primers of 25 oligonucleotides based on the marker have been synthesized and used to screen further M. floribunda clone 821, scab-susceptible apple cultivars, scab-resistant apple cultivars, and scab-resistant Coop selections. The sequence-specific primers have identified polymorphisms of OPK16/1300 based on the presence or absence of a single band.

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 Effect of pruning on disease incidence of apple scab and powdery mildew in integrated and organic apple production

2005 ◽  
Vol 11 (1) ◽  
Author(s):  
I. J. Holb
Keyword(s):  
Powdery Mildew ◽  
Production System ◽  
Production Systems ◽  
Venturia Inaequalis ◽  
Disease Incidence ◽  
Apple Scab ◽  
Organic Production ◽  
Environmentally Benign ◽  
Apple Cultivars ◽  
Apple Production

In a three-year study, the effect of two winter pruning treatments (strong and weak) on apple scab (Venturia inaequalis) and powdery mildew (Podosphaera leucotricha) was evaluated on six apple cultivars (`Rewena', `Elstar', 'Liberty', 'Gala', 'Pilot' and `Jonica') in two environmentally-benign apple production systems (integrated and organic). Results on apple scab showed that compared to the integrated production system, the pathogen caused significantly more infection on the leaves of cvs. `Elstar', 'Gala' and `Jonica' in the organic production system. The effect of pruning treatments on apple scab was mainly detectable on the cultivars susceptible to the disease such as cvs. 'Gala' and `Jonica'. The weak pruning correlated with a higher level of apple scab infection than the strong pruning, especially in the organic production system. Primary mildew infection was very low in both protection systems (below 2 %), therefore, effect of pruning on primary mildew infection could not be analysed. Low secondary mildew incidence was detected in the organically treated orchard part; however, incidence of powdery mildew was significantly higher (P> 0.05) on cvs. 'Elstar', 'Pilot' and `Jonica' in the integrated orchard part compared to cvs. 'Gala', 'Rewena' and 'Liberty'. The highest incidence of mildew was on cv. 'Elstar'. Pruning had very low effect on incidence of secondary mildew infection on leaves.

scholarly journals New North American isolates of Venturia inaequalis can overcome apple scab resistance of Malus floribunda 821

2019 ◽  
Author(s):  
David Papp ◽  
Jugpreet Singh ◽  
David Gadoury ◽  
Awais Khan
Keyword(s):  
New York ◽  
Genetic Structure ◽  
Population Genetic Structure ◽  
Population Genetic ◽  
Venturia Inaequalis ◽  
Durable Resistance ◽  
Apple Scab ◽  
Scab Resistance ◽  
Breeding Programs ◽  
Malus Floribunda

AbstractApple scab, caused by Venturia inaequalis (Cke.) Wint., is a destructive fungal disease of major apple cultivars worldwide, most of which are moderately to highly susceptible. Thus, development of scab resistant cultivars is one of the highest priorities of apple breeding programs. The principal source of resistance for breeding programs has been the scab resistance gene Rvi6 that originated from the Japanese crabapple Malus floribunda (Sieb.) sel. 821. Isolates of V. inaequalis able to overcome Rvi6 have been identified in Europe, but have not yet been reported on the American continents. We recently discovered scab infection on M. floribunda 821 trees in a research orchard at Geneva, New York, USA, where approximately 10% of the leaves bore profusely sporulating apple scab lesions, many of which had coalesced to cover entire leaves. Chlorosis and pinpoint pitting symptoms typical of failed infections by V. inaequalis on hosts bearing the Rvi6 and Rvi7 genes were also observed. We assessed genetic diversity and population genetic structure of six V. inaequalis isolates collected from M. floribunda 821, one isolate from ‘Nova Easygro’, one isolate from ‘Golden Delicious’ and two isolates from Europe (11 isolates in total) using 16,321 genome-wide SNPs. Population genetic structure and PCA separated the isolates into distinct European and USA groups. The forgoing suggests that the new Rvi6 virulent isolates emerged within USA populations, rather than being transported from Europe. The overcoming of resistance in M. floribunda 821 but not in descendant cultivars suggests that durable resistance to apple scab will require a more comprehensive understanding of Rvi6 mediated resistance in diverse genetic backgrounds.

Sign in / Sign up

Export Citation Format

Share Document