Testing of Czech cultivars and advanced selections of apples for fire blight (Erwinia amylovora) resistance

Following the first outbreak of fire blight caused by the bacterium Erwinia amylovora (Burrill) Winslow et al. in Hungary, we have started research with the aim to screen domestic gene sources, mostly historical Hungarian apple cultivars, for disease resistance as part of an apple breeding program for multiple resistance. The present study was conducted with the aim to choose the most tolerant historical apple cultivars among 25 selected cultivars by screening their behavior towards fire blight under controlled conditions. Six cultivars were shown to be the most disease tolerant: `Batul', 'London pepin', Nemes Sóvári Alma', `Sikulai', `Szemes alma', Wilmos renet'. We evaluated these cultivars by investigating both morphological- characteristics under original environmental circumstances and fruit quality. The cultivars had a remarkable degree of fire blight resistance compared to the control cultivars. These were not competitive with the commercially grown 'Jonathan M40' during cultivar tests but on the basis of certain characteristics they could serve as genetic sources for breeding new varieties.

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Historical apple cultivars that display high level of resistance to fire blight

International Journal of Horticultural Science ◽

10.31421/ijhs/10/3/498 ◽

2004 ◽

Vol 10 (3) ◽

pp. 19-23

Author(s):

K. Kása ◽

M. G. Tóth ◽

M. Hevesi

Keyword(s):

Disease Resistance ◽

Fruit Quality ◽

Fire Blight ◽

Erwinia Amylovora ◽

Morphological Characteristics ◽

Blight Resistance ◽

Multiple Resistance ◽

New Varieties ◽

Apple Cultivars ◽

High Level

Following the first outbreak of fire blight caused by the bacterium Erwinia amylovora (Burrill) Winslow et al. in Hungary, we have started research with the aim to screen domestic gene sources, mostly historical Hungarian apple cultivars, for disease resistance as part of an apple breeding program for multiple resistance. The present study was conducted with the aim to choose the most tolerant historical apple cultivars among 25 selected cultivars by screening their behavior towards fire blight under controlled conditions. Six cultivars were shown to be the most disease tolerant: `Batul', 'London pepin', Nemes Sóvári Alma', `Sikulai', `Szemes alma', Wilmos renet'. We evaluated these cultivars by investigating both morphological- characteristics under original environmental circumstances and fruit quality. The cultivars had a remarkable degree of fire blight resistance compared to the control cultivars. These were not competitive with the commercially grown 'Jonathan M40' during cultivar tests but on the basis of certain characteristics they could serve as genetic sources for breeding new varieties.

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Inflorescence blast and flower bud abnormalities of Spiraea × vanhouttei and their causes

Czech Journal of Genetics and Plant Breeding ◽

10.17221/1898-cjgpb ◽

2008 ◽

Vol 43 (No. 4) ◽

pp. 135-143 ◽

Cited By ~ 2

Author(s):

V. Kůdela

Keyword(s):

Seed Production ◽

Fire Blight ◽

Erwinia Amylovora ◽

Small Scale ◽

Flower Bud ◽

The Czech Republic ◽

Hybrid Species ◽

High Incidence ◽

The Subject ◽

Very High

In ornamental gardening, Spiraea × vanhouttei is a frequently planted spirea species in the Czech Republic. In 2003, there arose a suspicion of possible occurrence of fire blight caused by Erwinia amylovora on spirea shrubs in Prague and its environs. This suspicion was disproved for a certainty. The absence of the fire blight pathogen in symptomatic spirea plants stimulates a further effort to tackle the problem of a cause of conspicuous fire blight-like symptoms or inflorescence blast occurring on some spirea shrubs. The subject of this paper is: (i) to describe symptoms, incidence and severity of inflorescence blast, bud and flower abnormalities occurring in Spiraea × vanhouttei shrubs; (ii) to find out differences in the occurrence of blasted inflorescences between Spiraea species and cultivars with the intention of verifying the hypothesis that the blast inflorescence and sterility of some spirea species are associated with hybrid species. Symptoms of inflorescence blast are every growing season. No seed is produced by blasted inflorescences. Besides inflorescence blast, aborted floral buds appeared sporadically on a small scale. Spirea species were split into four categories according to the incidence of blasted inflorescences. Out of 52 species evaluated, 10% showed no or scarce incidence, 52% medium incidence, 27% high incidence and 11% very high incidence. The scarce incidence of blasted inflorescences was connected with the high seed production. And vice versa, very high incidence of blighted inflorescences was closely connected with no or low seed production or with high incidence of sterility. Fifteen out of the evaluated spirea species are the result of hybridization. These hybrids occur in each of the four categories of spirea species distinguished by the incidence of blasted inflorescence. However, it is remarkable that the highest incidence of hybrid spireas occurs in the category with the highest incidence of blasted inflorescence (83.33%). In the remaining three categories of spirea species, the proportion of hybrids ranged from 18 to 21%. It might indicate some connection of spirea hybrids with sterility.

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Fire Blight Resistance of Budagovsky 9 Apple Rootstock

Plant Disease ◽

10.1094/pdis-92-3-0385 ◽

2008 ◽

Vol 92 (3) ◽

pp. 385-391 ◽

Cited By ~ 6

Author(s):

Nicole L. Russo ◽

Terence L. Robinson ◽

Gennaro Fazio ◽

Herb S. Aldwinckle

Keyword(s):

Fire Blight ◽

Erwinia Amylovora ◽

Growth Habit ◽

Blight Resistance ◽

Apple Rootstock ◽

Apple Rootstocks ◽

Phenotypic Differences ◽

Age Related ◽

Multiple Trials ◽

High Level

Erwinia amylovora, the causal agent of fire blight, can cause a fatal infection of apple rootstocks known as rootstock blight. Budagovsky 9 (B.9) apple rootstock is reported to be highly susceptible when inoculated with E. amylovora, although results from multiple trials showed that B.9 is resistant to rootstock blight infection in field plantings. Conflicting results could stem from genetic variation in the B.9 population, appearing as phenotypic differences in rootstock material. However, genetic testing, using 23 microsatellite loci, confirmed the clonal uniformity of B.9 in commerce. Variation in growth habit between B.9 rootstocks originating from two nurseries also has been discounted as a source of disease resistance. Instead, results indicate a possible novel resistance phenotype in B.9 rootstock. B.9 rootstock was susceptible to leaf inoculation by E. amylovora, statistically similar to the susceptible rootstock Malling 9 (M.9). Conversely, inoculation assays targeting woody 4- to 5-year-old tissue revealed a high level of resistance in B.9, whereas M.9 remained susceptible. Although the mechanism by which B.9 gains resistance to E. amylovora is unknown, it is reminiscent of age-related resistance, due to an observed gain of resistance in woody rootstock tissue over succulent shoot tissue. Durable fire blight resistance correlated with tissue development could be a valuable tool for rootstock breeders.

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Resistance of apple varieties and selections to Erwinia amylovora in the Czech Republic

Plant Protection Science ◽

10.17221/19/2008-pps ◽

2008 ◽

Vol 44 (No. 3) ◽

pp. 91-96 ◽

Cited By ~ 7

Author(s):

J. Korba ◽

J. Šillerová ◽

V. Kůdela

Keyword(s):

Czech Republic ◽

Fire Blight ◽

Erwinia Amylovora ◽

Relative Resistance ◽

Lesion Development ◽

The Czech Republic ◽

Apple Cultivars ◽

Moderately Resistant ◽

Resistant Genotypes ◽

Experimental Plots

Sixty-four apple cultivars and selections of potential interest to apple producers and plant breeders in the Czech Republic were tested for their relative resistance to the fire blight pathogen over six years. Level of fire blight resistance was evaluated according to the extent of lesion development on the shoots tips after artificial inoculation in experimental plots under insectproof nets. Cultivars Quinte (resistant) and Yellow transparent (high susceptible) were included in the tests. Of 64 apple cultivars and selections tested, none were high resistant, 3.1% were evaluated as resistant, 10.9% moderately resistant, 57.8% moderately susceptible, 21.9% susceptible and 6.3% high susceptible. Resistant apple genotypes, showing blight necrosis of shoots of 11–12%, were only cultivars Selena and Quinte. Moderately resistant genotypes (blight necrosis 13.1–25.0%) were Kordona, Golden Smoothee, Julia, HL 323, Melodie, HL 421 and S 634/3. High susceptible genotypes (blight necrosis more then 80.1%) were comprised cultivars Vesna, Topas, Yellow transparent and Vanda. The remaining genotypes were moderately susceptible (blight necrosis 26.1–60.0%) and susceptible (blight necrosis 60.1–80.0%). During six experimental years, quantitative variability was recorded in the blight score. Differences between cultivars in susceptibility to fire blight were often statistically significant.

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