Shoot and Blossom Susceptibility to Fireblight of Apple Cultivars

Lezec, M. Le; Paulin, J.P.; Lecomte, Pascal

doi:10.17660/actahortic.1987.217.54

Cited by 10 publications

(11 citation statements)

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“…In most cases, resistance/susceptibility levels agreed with previously reported levels (Aldwinckle & Preczewski, ; Le Lezec et al ., ; Aldwinckle et al ., ; Mohan et al ., ; van der Zwet et al ., ). For example, Jonathan consistently developed severe symptoms of fire blight in both years whereas Russian seedling #12740‐7 consistently showed HR responses.…”

Section: Discussionmentioning

confidence: 99%

“…Multiple cultivars in this study consistently showed similar or more resistance than Delicious, indicating the potential for increasing resistance to fire blight. This study confirmed the resistance of several cultivars including Empire, Enterprise, Fiesta, Liberty, Prima and Redfree, which have previously demonstrated moderate to high levels of resistance in other studies (Aldwinckle & Preczewski, ; Le Lezec et al ., ; Aldwinckle et al ., ; Mohan et al ., ; van der Zwet et al ., ; Harshman et al ., ). Fiesta and Splendour had intermediate to MR responses; however, these two cultivars had slightly higher est.…”

Section: Discussionmentioning

confidence: 99%

“…Through pedigree-informed analysis, van de Weg et al (2018) determined that the favourable resistance allele FB_F7 of the major QTL was derived from Cox's Orange Pippin; however, without the presence of additional putative QTLs, the effect of FB_F7 was relatively minor. Cox's Orange Pippin has been classified as MS (Le Lezec et al, 1987). Fiesta was classified as MS to MR whereas Enterprise was HR.…”

Section: Discussionmentioning

confidence: 99%

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Novel metrics to classify fire blight resistance of 94 apple cultivars

2019

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Fire blight (Erwinia amylovora), a potentially devastating disease in apple, can cause floral, fruit and structural damage and even tree death. Most commercial apple cultivars are susceptible and the resistance/susceptibility of many modern cultivars has not been evaluated. Fire blight resistance/susceptibility is difficult to phenotype due to quantitative resistance, impacts of tree vigour and environment on susceptibility, and the erratic nature of the disease. Resistance/susceptibility levels were determined for 94 apple cultivars and important breeding parents. In 2016 and 2017, multiple actively growing shoots per tree (about three trees per cultivar) were challenged with E. amylovora Ea153n via a cut‐leaf inoculation method. Proportion of current season's shoot length blighted (SLB) was calculated for each shoot. To classify cultivar responses, estimated marginal SLB means were compared to four controls, representing highly susceptible (HS) to highly resistant (HR), via Dunnett's tests. Cultivar responses ranged from HS to HR with estimated marginal SLB means of 0.001–0.995 in 2016 and 0.000–0.885 in 2017. Most cultivars demonstrated similar resistance/susceptibility levels in both years (ρ = 0.657, P < 0.0001). K‐means clustering was used to classify cultivars into three resistance/susceptibility groups based on incidence, average severity (SLB), and maximum severity values (maximum SLB and age of wood infected). Sixteen cultivars were consistently moderately resistant (MR) to HR while the remainder ranged from HS to MR. An updated comparison of susceptibility of important cultivars is provided. Resistance/susceptibility information gained could be used to identify genetic loci associated with resistance/susceptibility and/or inform parental selection in apple scion breeding programmes.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Novel metrics to classify fire blight resistance of 94 apple cultivars

2019

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“…Several researchers reported the relative field resistance of apple cultivars from orchard evaluations in natural epidemics or following controlled inoculation (see van der Zwet and Keil, 1979 for an extensive review of cultivar comparisons and also den Boer and Green, 1995;Bonn and Elfving, 1990;Fischer and Schaefer, 1990;Fischer et al, 1983a;Gardner et al, 1980a;Le Lezec et al, 1987;Thomas and Jones, 1992). The inheritance of fire blight resistance in apple has been studied mainly following inoculation with single or mixed strains of young juvenile seedlings in greenhouses (Aldwinckle and Cummins, 1979;Fischer, resistance under these conditions to aid in determining if this germplasm can be enhanced for fire blight resistance via selection.…”

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confidence: 99%

Field Resistance to Fire Blight in a Diverse Apple (Malus sp.) Germplasm Collection

Luby¹,

Alspach²,

Bus³

et al. 2002

jashs

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Incidence and severity of fire blight [Erwinia amylovora (Burr.) Winslow, Broadhurst, Buchanan, Krumwiede, Rogers, and Smith] following field infection were recorded using families resulting primarily from open-pollination of Malus sylvestris (L.) Mill. var.domestica (Borkh.) Mansf. cultivars and a few other Malus Mill. sp. The families were structured as three sublines, planted in three successive years (1992 to 1994), of a diverse population of apple germplasm established at HortResearch, Hawkes Bay, New Zealand. The incidence of fire blight varied among the sublines with the oldest planting exhibiting more fire blight. Flowering trees were more likely to be infected than nonflowering trees, in terms of both incidence and severity. Furthermore, the level of fire blight was related to flowering date, with later flowering trees having higher levels. Thus, family means and narrow-sense heritability estimates were computed after first adjusting the fire blight score for flowering date by fitting a linear model. Provenance of origin of the maternal parent explained little variation except that M. sieversii Lebed. families were more resistant than M. sylvestris var. domestica families in one subline. Family means computed using all trees, and those from only flowering trees were highly correlated. Families from open-pollination of M. honanensis Rehder and M. xhartwiggii Koehne females were among the more susceptible. Those from several European M. sylvestris var. domestica cultivars as well as from M. baccata (L.) Borkh. and M. toringoides (Rehder) Hughes females were among the more resistant families. Narrow-sense heritability estimates ranged from 0.05 to 0.85 depending on the subline, with most estimates between 0.12 and 0.36. They were higher in the two older sublines that consisted primarily of open-pollinated families from M. sylvestris var. domestica, and lower in the younger subline that consisted primarily of M. sieversii, due to lower incidence and severity in the latter subline. Breeders who consider potential complications of juvenility, tree size, and flowering date in relation to infection periods should be able to exploit field epidemics to perform effective selection.

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“…Shoot necrosis of apple cultivars was expressed as the percentage of total shoot length in cm (Le Lezec & Paulin, 1984; Le Lezec et al ., 1987) 28 days after inoculation. Classes of resistance were defined by modifying the proposal of Gardner et al .…”

Section: Methodsmentioning

confidence: 99%

Traditional and commercial apple and pear cultivars as sources of resistance to fireblight¹

Hevesi¹,

Göndör²,

Kasa³

et al. 2004

EPPO Bulletin

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In Hungary, fireblight research programmes were initiated on pear in 1999 and on apple in 2000, with the aim of evaluating the susceptibility or resistance of commercial cultivars. Sources of resistance for future breeding were also sought among traditional apple cultivars collected from Ukraine and pear cultivars in the Hungarian gene bank (Szigetcsép). Experiments were done under secure conditions. Inocula were mixtures of characteristic Erwinia amylovora isolates from pear and apple in Hungary. Host responses (symptom development, disease severity and multiplication rate of bacterial cells in host tissues) were assessed on shoots, flowers and fruits. About 30 pear and 30 apple cultivars, and 35 apple hybrids, were tested and grouped into four categories for pear and three for apple. Of the pear cultivars tested, 50% were susceptible, 30% moderately susceptible and only 10% of low susceptibility. Different plant organs occasionally displayed different responses. Members of the last two groups might serve as useful candidates for growing under IPM conditions. Among the traditional Hungarian varieties tested, we found high resistance in 'Sikulai' and 'Szemes alma', which could be used as sources of fireblight resistance in breeding programmes and also grown in organic orchards. Furthermore, among the offspring of the apple 'Prima' (scab-resistant), we have found highly resistant lines.

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Shoot and Blossom Susceptibility to Fireblight of Apple Cultivars

Cited by 10 publications

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Novel metrics to classify fire blight resistance of 94 apple cultivars

Novel metrics to classify fire blight resistance of 94 apple cultivars

Field Resistance to Fire Blight in a Diverse Apple (Malus sp.) Germplasm Collection

Traditional and commercial apple and pear cultivars as sources of resistance to fireblight¹

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Shoot and Blossom Susceptibility to Fireblight of Apple Cultivars

Cited by 10 publications

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Novel metrics to classify fire blight resistance of 94 apple cultivars

Novel metrics to classify fire blight resistance of 94 apple cultivars

Field Resistance to Fire Blight in a Diverse Apple (Malus sp.) Germplasm Collection

Traditional and commercial apple and pear cultivars as sources of resistance to fireblight1

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Traditional and commercial apple and pear cultivars as sources of resistance to fireblight¹