scholarly journals Application of DNA markers for detection of scab resistant apple cultivars and selections

Author(s):  
H. Mattisson ◽  
H. Nybom

A DNA marker-based study was undertaken to identify the occurrence of major scab resistance genes in some apple cultivars and selections of importance for apple breeding. Unfortunately none of the RAPD-based markers previously reported to detect the Va, Vb, Vr and Vx genes produced unambiguous results. By contrast, the CAPS marker MI8 produced the expected three bands in all cultivars and selections already known or suspected to have the Vf gene, as well as in the Russian cultivar 'Antonovka Polotora Funtovaja' suspected to have Va resistance which however may be allelic to Vf. Vf-carrying selections and newly named cultivars 'Frida' and 'Fredrik' are grown successfully in Sweden without fungicides, suggesting that the Vr resistance breaking scab races 6 and 7 have not yet become a problem. The SCAR marker B12 detected the Vm gene in 'Prairifire', 'Rouville', clones 'OR45T132' and 'OR48T70', and selection '16-36-193'. The SSR locus 0102b10 detected one band at 118 by in 'Reka'. This is presumed to be identical to the Vr gene marker previously reported.

2004 ◽  
Vol 94 (4) ◽  
pp. 370-379 ◽  
Author(s):  
F. Calenge ◽  
A. Faure ◽  
M. Goerre ◽  
C. Gebhardt ◽  
W. E. Van de Weg ◽  
...  

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.


Italus Hortus ◽  
2021 ◽  
Vol 28 (1) ◽  
pp. 32
Author(s):  
Raffaele Testolin ◽  
Luigi Falginella ◽  
Alberto De Carli ◽  
Gloria De Mori ◽  
Guido Cipriani

Apple breeding is active worldwide and yet the apple crop is in a precarious state as it relies on few dominant cultivars and only the Rvi6 (formerly Vf) gene, that confers resistance to scab, has been extensively exploited in the cultivars entered the market in recent years. However, there are some 20 disease resistance genes described in apple and the apple germplasm includes thousands of accessions in the repositories. In this paper, a breeding programme is described, whereby 36 genotypes, including ancient and contemporary apple cultivars, were crossed to produce a new set of selections that combine extensive genetic resources with pyramided resistance genes to several apple diseases, such as scab and powdery mildew. The 110 cross combinations carried out successfully, of the 260 initially planned, produced 7,876 offsprings, reduced to 2,969 after screening with molecular markers associated with five resistance genes. Selections with three or two resistance genes and good agronomic characteristics were kept for further field observations with the aims of creating new cultivars for the market and new parents for future breeding projects


Author(s):  
Atifa Rasool ◽  
K. M. Bhat ◽  
H. U. Rehman ◽  
M. A. Mir ◽  
Shafia Zaffar ◽  
...  

The present investigation entitled “Allelic diversity in apple germplasm for fruit quality and scab resistance using SSR markers” was conducted in division of plant biotechnology, SKUAST-K, Shalimar during the year 2018. In the present study, four SSR markers namely Md-ACS-1, Md-ACO-1, ALO-7 and AM-19 were used for screening of 40 apple cultivars presently under cultivation in SKUAST-K for quality and scab resistance. The results revealed that out of 40 cultivars evaluated, 3 were found homozygous (ACS-1-2/2), 17 were heterozygous (ACS-1-1/2) and 10 were homozygous (ACS-1-1/1), while as no amplification of ACS-1 was found for 10 cultivars. Similarly, for Md-ACO-1, 3 cultivars were found homozygous, 35 as heterozygous and 2 did not show any amplification. As far as presence of Vf gene conferring resistance against scab disease, ALO-7 amplified at 820bp and 570bp alleles, 570 bp fragment was observed in resistant genotypes and was absent in susceptible genotypes, while the 820 amplicon was observed in both resistant and susceptible genotypes. The markers AM19 led to the amplification of 520 bp fragment in few cultivars.


2021 ◽  
Vol 22 (3) ◽  
pp. 340-350
Author(s):  
A. V. Bakulina ◽  
L. S. Savintseva ◽  
O. N. Bashlakova ◽  
N. F. Sintsova

The genotypes of potatoes bred by Falenki Breeding station were studied for the presence of resistance genes markers to the following pathogens: Globodera rostochiensis, Globodera pallidа, Synchytrium endobioticum, potato virus X (PVХ) and potato virus Y (PVY). The method of multiplex PCR analysis was used. The varieties Shurminsky 2, Alisa, Viza, Chayka, Ognivo, Darik, Gloriya, Golubka, Virazh and a promising variety sample 56-09 were studied. In most (8 out of 10) genotypes, marker linked to the Sen1 gene of resistance to S. endobioticum was identified. DNA marker of the G. rostochiensis resistance gene (H1) and the G. pallida resistance gene marker (Gpa2) were found in six genotypes. The marker of the PVX resistance gene (Rx1) was detected in the varieties Shurminsky 2, Alisa, Chayka, Golubka, and Virazh. It has been established that none of the studied potato genotypes carries markers RYSC3, Ry186, YES3-3A linked to the PVY resistance genes. Although in the field, resistance was detected in the samples Chayka, Darik, Virazh, Alisa. Molecular markers linked to the largest number of resistance genes studied (H1, Gpa2, Sen1, and Rx1) were identified in the varieties Shurminsky 2, Golubka, and Virazh. Among the DNA markers used in the work, the data of potato genotype assessment using markers of virus resistance genes (PVX, RYSC3, Ry186, YES3-3A) were less consistent with field observations. The use of molecular markers makes it possible to determine the presence of resistance genes and assess the prospects of a sample in a short period of time, but, at the same time, requires careful choice of a DNA marker that is highly correlated with the manifestation of the trait.


2020 ◽  
Vol 56 (No. 4) ◽  
pp. 165-169
Author(s):  
Lefkothea Karapetsi ◽  
Irini Nianiou-Obeidat ◽  
Antonios Zambounis ◽  
Maslin Osathanunkul ◽  
Panagiotis Madesis

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.


Author(s):  
M. Tóth

An apple breeding program has been carried out at the Department of Fruit Science for more than a decade. Several apple selections have been released from the progenies of crosses in 1992 and 1993. Six candidates were submitted for national recognition out of the hybrids examined for more than a decade. The six selections are resistant against all the three most important apple diseases (apple scab, powdery mildew and fire blight). Scab resistance is controlled by the Vf gene originating from the species Malus floribunda 821 and transmitted by cultivar Prima. Heterozygote Vfvf genotype of the six cultivar candidates was proved by molecular genetic examinations of Dept. Genetics and Plant Breeding. Characteristics of these selections from 'Prima' progenies are shown on the base of our own observations.


Author(s):  
M. V. Makarkina ◽  
E. T. Ilnitskaya ◽  
S. V. Tokmakov

DNA-marker analysis of grape genotypes for the presence of downy mildew resistance genes Rpv3 and Rpv12 was performed. Table and seedless grapes varieties and forms carring these resistance genes were identified according to the DNA-marker evaluation.


Author(s):  
М.I. Dulov ◽  

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.


Plant Disease ◽  
2020 ◽  
Vol 104 (8) ◽  
pp. 2074-2081 ◽  
Author(s):  
Andrea Patocchi ◽  
Andreas Wehrli ◽  
Pierre-Henri Dubuis ◽  
Annemarie Auwerkerken ◽  
Carmen Leida ◽  
...  

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.


1996 ◽  
Vol 121 (5) ◽  
pp. 773-782 ◽  
Author(s):  
Dominique A.M. Noiton ◽  
Peter A. Alspach

Pedigrees of apple (Malus ×domestica Borkh.) cultivars were used to study worldwide genetic diversity among clones used in modern apple breeding. The most frequent founding clones were `Cox's Orange Pippin', `Golden Delicious', `Red Delicious', `Jonathan', and `McIntosh'. Coefficients of coancestry between 50 mainstream cultivars and these clones averaged 0.03, 0.12, 0.07, 0.06, and 0.02, respectively, but they were frequently as high as 0.25 with certain pairings. Among a group of 27 cultivars carrying the Vf gene for scab resistance, coefficients of coancestry with the five founding clones were of the same order. Although few of the cultivars sampled were substantially inbred, inbreeding could reach serious levels in their future offspring if current breeding practices are continued. The status effective number was 8 for the mainstream group and 7 for the Vf-carrier clones. This indicates clearly that apple breeders are operating with a population of greatly reduced genetic diversity. Careful consideration of pedigrees and increased size of the genetic base are needed in future apple breeding strategies.


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