scholarly journals The effect of wood age on infection by Neonectria ditissima through artificial wounds on different apple cultivars

2017 ◽  
Vol 70 ◽  
pp. 97-105 ◽  
Author(s):  
N.T. Amponsah ◽  
R.W.A. Scheper ◽  
B.M. Fisher ◽  
M. Walter ◽  
J.M. Smits ◽  
...  
Keyword(s):  
Disease Progression ◽  
Disease Incidence ◽  
Age Effect ◽  
The Other ◽  
Lesion Length ◽  
Wood Age ◽  
Golden Delicious ◽  
Apple Cultivars ◽  
Glasshouse Experiment

The age of apple wood may affect its susceptibility to European canker (Neonectria ditissima). Therefore, a glasshouse experiment was conducted with potted trees of six apple cultivars (‘Braeburn’, ‘Scilate’, ‘Fuji’, ‘Golden Delicious’, ‘Jonathan’ and ‘Royal Gala’) grafted onto two rootstocks (‘M793’ and ‘M9’) to study the effect of 3-, 2- or 1-year-old wood on incidence and disease progression following inoculation with conidia of N. ditissima. Initial analyses of cultivars on ‘M793’ showed a significant wood age effect on disease incidence and lesion length, which was similar to cultivars grafted on ‘M9’. Three-year-old wood developed more and longer lesions than either the 2- or the 1-year-old wood. A significant cultivar effect was observed with ‘Royal Gala’ developing more lesions than the other cultivars tested. More than half of asymptomatic wounds placed onto apple sap-amended water agar for pathogen isolation yielded N. ditissima.

scholarly journals Effect of Leaf Wetness Duration, Temperature, and Conidial Inoculum Dose on Apple Scab Infections

Plant Disease ◽  
1999 ◽  
Vol 83 (6) ◽  
pp. 531-534 ◽  
Author(s):  
J. R. Hartman ◽  
L. Parisi ◽  
P. Bautrais
Keyword(s):  
Venturia Inaequalis ◽  
Disease Incidence ◽  
Apple Scab ◽  
The Other ◽  
Leaf Wetness ◽  
Leaf Wetness Duration ◽  
Inoculum Dose ◽  
Golden Delicious ◽  
Wetness Period ◽  
Series Of Experiments

Apple seedlings (2 months old, ‘Idared’ × ‘Golden Delicious’) were inoculated with conidia of Venturia inaequalis in order to study the effects of inoculum dose and leaf wetness duration on development of apple scab symptoms. For each experiment, the C3 curve (indicating heavy infection levels) was used as the basis for relating infection to temperature and leaf wetness duration. In one series of experiments, seedlings were treated with inoculum doses of 1.5, 5.4, 15.6, 32.2, 81.2, and 250 × 103 conidia/ml and leaves were kept wet during C3 infection periods at temperatures of 6, 11, 16, and 22°C. At all four temperatures, disease incidence (scab lesions/plant) increased with increasing inoculum doses up to about 81.2 × 103 conidia/ml. Disease incidence was lower at 22°C than at the other temperatures. In a second series of experiments, seedlings inoculated with 10 × 103 conidia/ml were kept moist for infection periods ranging from 0.6 to 2.0 times the C3 leaf wetness duration curve at 6, 11, 16, and 22°C. Disease incidence increased with increasing duration of leaf wetness and generally leveled off between 150 and 200% of the C3 curve. At this inoculum dose (10 × 103 conidia/ml), doubling the leaf wetness duration indicated by the C3 curve resulted in high disease incidence, similar to levels obtained with a higher inoculum (250 × 103 conidia/ml) and shorter wetness period (1.0 C3).

Phytotoxicity of methyl bromide fumigation to a range of apple cultivars

1977 ◽  
Vol 17 (88) ◽  
pp. 853 ◽  
Author(s):  
JB O'Loughlin ◽  
JE Ireson
Keyword(s):  
Methyl Bromide ◽  
The Other ◽  
Golden Delicious ◽  
Apple Cultivars ◽  
Storage Disorder ◽  
Different Levels

Two trials were conducted to study the phytotoxicity of methyl bromide fumigation to a range of apple cultivars. Crofton was highly susceptible, being injured by all concentration x temperature combinations studied. Democrat was moderately susceptible, being injured by 32, 48 and 64 g m-3. The cultivars Red Delicious, Jonathan and Granny Smith had a relatively low susceptibility as they were injured only slightly by 32 g m-3 methyl bromide at 15�C. The other cultivars, namely Legana and Golden Delicious, were not injured by any of the dosages. The amount of injury in Croftons and Democrats varied from orchard to orchard. Dosagehemperature combinations considered equivalent for efficacy purposes resulted in different levels of methyl bromide injury on these two cultivars. Spartan was the only cultivar in which any dosages of methyl bromide produced significantly more of the storage disorder internal breakdown than occurred in non-fumigated fruit.

Relative Susceptibility of Selected Apple Cultivars to Powdery Mildew Caused by Podosphaera leucotricha

2009 ◽  
Vol 10 (1) ◽  
pp. 3 ◽  
Author(s):  
Alan R. Biggs ◽  
Keith S. Yoder ◽  
David A. Rosenberger
Keyword(s):  
Powdery Mildew ◽  
Disease Incidence ◽  
Cultivar Differences ◽  
Susceptible Cultivar ◽  
Chronic Effect ◽  
Podosphaera Leucotricha ◽  
Yield Data ◽  
Golden Delicious ◽  
Regional Project ◽  
Apple Cultivars

Apple powdery mildew thrives during dry spring and summer weather wherever apples are grown. The fungus perennates in buds, making it difficult to control and, although it can cause fruit russet, it primarily causes losses due to its chronic effect on tree vigor and yield. Data were collected over several years from 1995 (23 entries) and 1999 (22 entries) plantings of new apple cultivars and selections established at multiple locations as part of regional project NE-183. The cultivars Golden Delicious and McIntosh were the standards in both plantings. Incidence of powdery mildew on leaves and fruit was observed and data were analyzed to determine differences due to location and cultivar. One of the two planting group analyses indicated the significance of cultivar differences due to location. In general, the cultivars Ginger Gold, Suncrisp, GoldRush, Crimson Crisp, and Delblush, and the selection CQR10T17 were the most susceptible, whereas the cultivars Gala Supreme, Enterprise, Zestar, September Wonder, Hampshire, and the selections NY 75414-1 and NY 79507-72 exhibited the lowest incidences of mildew. Pinova was the most highly susceptible cultivar to mildew on fruit in Virginia, followed by Crimson Crisp and the selection NY 65707-19. Percent leaf area with mildew was related to incidence of mildew on leaves; however, fruit symptoms were not significantly related to disease incidence or severity on the foliage. Accepted for publication 11 September 2009. Published 19 November 2009.

scholarly journals Detached shoot treatments cannot replace whole-tree assays when phenotyping for apple resistance to Neonectria ditissima

2018 ◽  
Vol 71 ◽  
pp. 151-157 ◽  
Author(s):  
Reiny W.A. Scheper ◽  
Brent M. Fisher ◽  
Tara Taylor ◽  
Duncan I. Hedderley
Keyword(s):  
Interaction Effect ◽  
Disease Incidence ◽  
The Other ◽  
Lesion Length ◽  
Whole Tree

To develop a fast phenotyping method for European canker resistance of apple, detached-shoot assays were compared with whole-tree phenotyping methods. Disease incidence and lesion length in detached shoots and potted trees of six apple accessions were compared after inoculation with Neonectria ditissima conidia in a glasshouse. Detached shoots were placed in aerated water or in a Chrysal solution, with and without water changes. ‘Royal Gala’ trees had the highest disease incidence (90%) and ‘Robusta 5’ trees remained lesion-free. The treatment-accession interaction effect was significant, with higher disease incidence in detached shoots of ‘Robusta 5’ (4—32%) than ‘Braeburn’ (0—2%), while ‘Braeburn’ trees had a high disease incidence (64%). ‘Robusta 5’ had smaller lesions than the other accessions, but significant differences between accessions were observed on only one of three assessment dates. None of the detached-shoot assays resulted in a similar ranking of the accessions compared with the potted-tree assay, using disease incidence or lesion length. Detached-shoot treatments cannot replace whole-tree assays when phenotyping for European canker resistance of apple.

Variation of Phytochemicals Content in Pulp and Skin of Seven Romanian Apple Cultivars

2017 ◽  
Vol 68 (3) ◽  
pp. 474-477
Author(s):  
Lacramioara Oprica ◽  
Doina Atofanei ◽  
Vladimir Poroch
Keyword(s):  
Antioxidant Activity ◽  
Ascorbic Acid ◽  
Anthocyanin Content ◽  
Colour Intensity ◽  
Total Polyphenol ◽  
Valuable Source ◽  
Golden Delicious ◽  
Apple Cultivars ◽  
Apple Fruits

The amounts of anthocyanins, flavonoids, total polyphenol and ascorbic acid in seven apple cultivars from Romania were investigated. The amounts of polyphenol and flavonoids in pulp and skin of apple cultivars ranged between 17.18�7.52 mg GAE/g DW and 20.10�11.06 mg CE/g DW as well as 3.64�1.18 mg GAE/g DW and 10.31�5.57 mg CE/g DW, respectively. The highest and smallest values of ascorbic acid both in the skin and the pulp were observed in the cultivars Mutsu and Starkrimson. The anthocyanin content is positively correlated with the colour intensity of the apple epicarp, being about three-fold higher in Prima than Golden Delicious cultivar. The better antioxidant activity provided by the content of polyphenol, ascorbic acid and flavonoids was in apple fruits of Mutsu cultivar and for this reason it should be regarded as a valuable source of antioxidants.

scholarly journals Seven-year orchard performance of eleven new apple cultivars from Holovousy in comparison with some commonly grown ones

2011 ◽  
Vol 33 (No. 4) ◽  
pp. 131-139 ◽  
Author(s):  
J. Blažek ◽  
J. Křelinová
Keyword(s):  
Early Summer ◽  
Trunk Diameter ◽  
Chemical Protection ◽  
Biennial Bearing ◽  
Fruit Samples ◽  
Golden Delicious ◽  
Apple Cultivars

 In an orchard trial that was established in the spring of 1999 on M 9 rootstock at the spacing of 4 × 1 m, eleven new apple cultivars bred in Holovousy (Angold, Julia, Nabella, Primadela, Produkta, Resista, Rubinstep, Rucla, Selena, Vysočina and Zuzana) were evaluated in comparison with three standard varieties (Gala, Golden Delicious and Jonagold) and another two with resistance to scab (Rosana and Topaz). In the first three years, the incidence of scab and mildew was evaluated under limited chemical protection. In 2000–2005 on each of 10 randomly selected trees of each cultivar, the time of flowering and optimum harvest ripening were recorded, flower set and fruit sets were rated, yield per tree and weight of 10 fruit samples were measured. Trunk diameter was measured between 2002 and 2005. The early summer apple Julia had the healthiest state and it was recommended for organic growing. Selena was the most precocious, the least vigorous and had the highest crop efficiency. The highest annual yields per tree were recorded with Produkta, but this cultivar had the highest proportion of trees with biennial bearing. Primadela achieved the highest cumulative yields, whereas Angold brought the largest fruits on average. With the obtained results, the evaluated cultivars were characterised by some important features or recommendations for growers.  

scholarly journals Variability in Postharvest Decay Among Apple Cultivars

Plant Disease ◽  
1999 ◽  
Vol 83 (11) ◽  
pp. 1051-1054 ◽  
Author(s):  
R. A. Spotts ◽  
L. A. Cervantes ◽  
E. A. Mielke
Keyword(s):  
Botrytis Cinerea ◽  
Fungal Pathogens ◽  
Decay Resistance ◽  
The Other ◽  
Penicillium Expansum ◽  
Epidermal Layer ◽  
Apple Industry ◽  
Mucor Piriformis ◽  
Apple Cultivars ◽  
Potential Decay

The level of resistance to decay caused by four fungal pathogens, the force required to break the epidermis, and the extent of open sinuses as measures of potential decay resistance were determined for the fruit of several apple cultivars. No single cultivar was the most resistant to each of the four pathogens in this study. In addition, each cultivar that was the most resistant to one pathogen also was the most susceptible to one of the other pathogens. However, Royal Gala was the most resistant to the wound pathogens Botrytis cinerea, Penicillium expansum, and Mucor piriformis. Fuji and Oregon Spur II were more resistant than other cultivars to Pezicula malicorticis. The epidermis (skin) of Fuji and Granny Smith were the most resistant to puncture, requiring an average of 81.5 and 87.0 Newtons, respectively, to break the epidermal layer. Fuji had the highest percentage of fruits with open sinuses, with a mean of 38%, whereas Braeburn had 0% of fruit with open sinuses. The cultivar information presented herein may be a valuable measure of decay resistance and may be of use to the apple industry.

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