scholarly journals Mining new scab resistance alleles in apple (Malus × domestica Borkh.) germplasm of Kashmir: Towards breeding scab free apple cultivars

Author(s):  
Jahangir Ahmad Dar ◽  
Sajad Majeed Zargar ◽  
Rameez Nazir Rather ◽  
Aijaz A. Wani

Apple an important fruit crop in Kashmir ranks first in all the fruits grown here. It is commercially the most important horticultural crop grown in temperate parts of the world. To control scab in Apple a lot of fungicides are being used however, an alternative approach to fungicide application is the use of scab resistant cultivars as a genetic stock. Therefore, there is an urgent need to identify more cultivars resistant to scab with maximum genes and can be used for apple breeding. In view of this, one hundred apple cultivars grown in Kashmir Valley were screened for the presence of Vf gene conferring resistance against apple scab. Eight trait linked markers were used so for and among them three markers like AL07, AM19, and CH05e03 proved to be useful to distinguish the resistant cultivars from the other apple germplasm. These three markers have amplified resistant fragments in five cultivars. Thus out of the total of 100 cultivars investigated in the present study, only five cultivars namely Shalimar I, Shalimar II, Dubhour, Gold Spur, and Crab apple were found to harbour resistant alleles which may be resistant to some of the races of V. inaequalis. Among the five cultivars harbouring the scab resistant alleles for some races of V. inaequalis, three cultivars namely, Shalimar I, Shalimar II, and Dubhour, which contain the maximum number of scab resistance alleles can be used as parents in further breeding programms to develop more resistant apple cultivars with high market acceptance.

2017 ◽  
Vol 38 (SI 2 - 6th Conf EFPP 2002) ◽  
pp. 600-603
Author(s):  
B. Gelvonauskis ◽  
D. Gelvonauskienė

Apple cultivars were crossed according to the half-diallel and topcross mating design. Apple scab resistance of seedlings was estimated by using a 0–5 scale: 0 – no infection on leaves, 5 – more than 75% of leaf area infected. Percentage of scab resistant seedlings in crosses involving cultivars Prima varied from 35.8% to 67.6%, involving cultivars Florina and Arbat – 51.9–59.5% and 53.5–72.5%, respectively. Significant differences for resistance to scab were found among the crosses. Both general combining ability (GCA) and specific combining ability (SCA) were highly significant. The significance of GCA for scab resistance shows that genetic variability exists for this trait and selection should result in genetic progress, because the mean square for GCA was larger than that calculated for SCA. Therefore, selection of parents on its phenotype should be effective for development of resistant apple cultivars. The significant SCA estimates indicate that a large number of resistant seedlings from particular crosses should be selected.


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.


HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 619a-619
Author(s):  
Hong Y. Yang ◽  
Schuyler S. Korban ◽  
Jutta Kruger ◽  
Hanna Schmidt

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.


2018 ◽  
Vol 46 (1) ◽  
pp. 115-121 ◽  
Author(s):  
Viorel MITRE ◽  
Erzsébet BUTA ◽  
Lehel LUKÁCS ◽  
Ioana MITRE ◽  
Răzvan TEODORESCU ◽  
...  

The control of apple scab and powdery mildew is a challenge for organic fruit growing. Bicarbonate salts are already consecrate in reducing the attack of scab and powdery mildew in organic apple culture. In the current study the influence of some products accepted in organic apple production to control scab and powdery mildew (potasium bicarbonate, lime sulphur, wettable sulphur, potassium silicate, cooper ammonium-phosphate, potassium bicarbonate + potassium silicate, potassium bicarbonate + wettable sulphur) in comparison with untreated control, were used.  The biological material was represented by three scab resistant cultivars (‘Luna’, ‘Topaz’ and ‘Sirius’) and three scab susceptible cultivars (‘Elstar’, ‘Pinova’ and ‘Golden Delicious’). The experiments were carried out during 2014-2016 at Steluța LTD, Cluj-Napoca, N.W. Romania, as a bifactorial experiment arranged in randomized blocks. The trees were planted in 2011 at a density of 3,175 trees/ha. Depending of the year, a number of 18-22 treatments were made annually after each rain. It can be concluded that the combination of potassium bicarbonate + wettable sulphur significantly reduced the attack degree of scab and powdery mildew on leaves and fruits and increased the yield of the scab-susceptible and scab resistant cultivars. Good results were obtained in the case of treatment with potassium bicarbonate with potassium silicate, potassium bicarbonate and cooper ammonium phosphate. The treatments with the products used in the experiments did not register symptoms of phytotoxicity on leaves or fruits, except lime sulphur and wettable sulphur and cooper ammonium phosphates.


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.


2020 ◽  
Vol 36 ◽  
pp. 5-11
Author(s):  
Mădălina Militaru ◽  
Monica Sturzeanu ◽  
Adina Iancu

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.


2011 ◽  
Vol 47 (No. 4) ◽  
pp. 156-165 ◽  
Author(s):  
J. Patzak ◽  
F. Paprštein ◽  
A. Henychová

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.


1997 ◽  
Vol 122 (1) ◽  
pp. 47-52 ◽  
Author(s):  
Hong Y. Yang ◽  
Schuyler S. Korban ◽  
Jutta Krüger ◽  
Hanna Schmidt

Almost 200 random sequence decamer primers were used to screen a pair of bulked samples of apple (Malus ×domestica Borkh.) DNA and that of the donor parent Malus floribunda Sieb. clone 821 for molecular markers linked to the Vf gene conferring resistance to apple scab [Venturia inaequalis (Cke.) Wint.]. Identified was a single primer that generated a polymerase chain-reaction (PCR) fragment, OPAR4/1400, from the donor parent M. floribunda clone 821 and the scab-resistant selections/cultivars bulk, but not from the scab-susceptible recurrent-parent bulk. Cosegregation analysis using a segregating apple progeny and polymorphism analysis of individual scab-resistant selections/cultivars confirmed that this marker was linked to the scab-resistance gene Vf OPAR4/1400 was then cloned and sequenced. Sequence-specific primers of 25 oligonucleotides based on the marker were developed and used to screen further M. floribunda clone 821, scab-susceptible apple cultivars, scab-resistant apple cultivars, and scab-resistant Purdue, Rutgers, and Univ. of Illinois apple breeding program selections. The sequence-specific primers identified polymorphisms of OPAR4/1400 based on the presence or absence of a single band. This molecular marker is at a distance of about 3.6 cM from the Vf gene.


HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 462g-463
Author(s):  
Richard E. Durham ◽  
Schuyler S. Korban

DNA was extracted from leaves of various Malus genotypes and used to screen synthetic decamer oligonucleotide primers. Samples from the following two groups were bulked: 1) seven scab-susceptible apple cultivars, and 2) 15 scab-resistant apple genotypes derived by introgressive hybridization from the previous group of cultivars. A third sample consisted of DNA extracted from Malus floribunda Sieb. clone 821, the original source of apple scab resistance for all genotypes in the second group. A total of 59 primers from kits A, L, and R (Operon Technologies) were screened. Amplified fragments were obtained for 93% of the primers tested, while random amplified polymorphic DNA (RAPD) fragments were detected among samples for 76% of the primers. One primer, A15, amplified a unique band in both M. floribunda clone 821 and the bulked scab-resistant sample. This RAPD marker, designated OA15900, identifies an amplified, introgressed fragment that likely corresponds to a region of the genome that may serve as a modifier for the scab resistance gene block V, derived from M. floribunda clone 821.


2020 ◽  
Vol 10 ◽  
Author(s):  
Nishu Yadav ◽  
Rohan Aggarwal ◽  
Monika Targhotra ◽  
P. K Sahoo ◽  
Meenakshi K. Chauhan

Abstract:: Psoriasis is an autoimmune disease of the skin that is chronic, inflammatory, recurring, and affects about 2-5 percent of the population of the world. For treating psoriasis, ample drugs and molecules are available. However, none are safe and efficient for treating the disease without sacrificing the compliance of the patient. Also, existing medications are intended to mitigate the signs and symptoms and 100% cure is not achieved. They do, however, concentrate on treating the illness and relieving the symptoms. Therefore, finding a delivery mechanism that can treat psoriasis safely and efficiently without sacrificing patient enforcement remains a critical task. Nano based formulations present a high prospect of overcoming the weakness of traditional formulations by providing dose reductions, reduced side effects, and dosage frequency with improved efficacy while herbal medicinal products can also be used as potential drugs against psoriasis as they are easily available and are safe. This review focuses primarily on the traditional strategies and recent discoveries of a range of anti-psoriatic drugs in metallic, polymer, and herbal-based formulations. Nanocarriers such as nanoparticles, dendrimers, micelles, nano-capsules, solid lipid nanoparticles (SLN), ethosome, liposomes have been elaborated. Also, studies relating to the use of phyto based plants in psoriasis has been discussed. Nano and herbal based formulations, in a nutshell, remain known as a promising approach for treating psoriasis.


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