• Food Science and Preservation
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• v.14 no.5
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• pp.457-461
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• 2007

We investigated the effects of both $CaCl_2$ treatment and modified atmosphere packaging (MAP) (compared with non-packaging on 'Fuji' apples from the Young-Joo region of Korea. Apples were dined into 5% (w/v) $CaCl_2$ solution for 15 min and then packaged with or without LDPE film (thickness: 0.025 mm) before cold storage at $0^{\circ}C$. Weight loss of applies in film packaging was lower than that of non-packaging applies, and the apple firmness resulting from $CaCl_2$ treatment and MAP was better than that of apples receiving control treatment. Also, $CaCl_2$ treatment and MAP resulted in improvements in titratable acidity, soluble solid content (SSC), and decay rate compared to control treatments. However, no significant differences in vitamin C content were found amongst apples receiving various treatment. the results suggest that a combination of postharvest calcium dipping and plastic film packaging may effectively preserve 'Fuji' apples, and that the combined treatment are better than either individual treatment.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.02a
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• pp.445-450
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• 2000

• Korean Journal of Environmental Agriculture
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• v.42 no.3
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• pp.239-252
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• 2023

Most apple trees in South Korea are grafted on M.9 and M.26 rootstocks; however, these rootstocks are susceptible to fire blight. Although M.7 rootstocks are moderately resistant to fire blight, they tend to exhibit excessive vigor, which is unsuitable for high-density planting, unless weak cultivars are used. This study investigated the vegetative growth, yield, and fruit quality of apple trees grafted onto M.7, M.9, or M.26 rootstocks to assess the feasibility of establishing high-density apple orchards domestically using the M.7 rootstock a period of seven years (1-7 years after planting). Rootstocks were tested using three cultivars with contrasting induced vigor and harvesting times: vigorous and late-maturing 'Fuji,' moderate vigor and middle-maturing 'Hongro,' and low vigor and early-maturing 'Sansa.' The planting density was maintained constant, with 190 trees per 10 a. Primary thinning (leaving only the king fruit on clusters) was performed, whereas secondary thinning (controlling crop load) was not. Vegetative growth, accumulated yield per 10 a, and yield efficiency varied depending on cultivars and rootstocks; however, the cultivars had a more notable effect on fruit quality than the rootstocks. Biennial bearing often occurred in the M.26 rootstock. 'Fuji'/M.7 was overly vigorous for high-density planting. The fruit quality and accumulated yield per 10 a of M.7 were similar to those of M.9 with the 'Hongro' and 'Sansa' cultivars. In particular, 'Hongro'/M.7 did not show tree vigor reduction due to heavy crop load, and the degree of biennial bearing in 'Sansa'/M.7 was not particularly high. These results indicated that high-density apple planting using the M.7 rootstock was achievable using the 'Hongro' and 'Sansa' cultivars.

• The Korean Journal of Mycology
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• v.51 no.2
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• pp.111-120
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• 2023

Three fungal strains designated as KNUF-23-MG32, KNUF-23-YC8, and KNUF-23-MJ82 were isolated from the abnormal symptomatic apple trees during screening fungal pathogens collected in Jeollanam-do and Gyeongsangbuk-do, Korea. These fungal strains were found to have similar cultural and morphological characteristics close to the genus Botryosphaeria. Morphological characteristics were matched with B. kuwatsukai CBS 135219 but different with B. dothidea KACC 45481 and B. sinensis HMAS 246714^T. Pathogenicity tests of strain KNUF-23-MG32 showed that this strain causes rot in Fuji apples. Molecular phylogenetic analysis based on the sequences of the internal transcribed spacer (ITS) regions, translation elongation factor 1-alpha (TEF1α), and partial β-tubulin (TUB2) showed that these strains are B. kuwatsukai. To the best of our knowledge, this is the first report of an apple ring rot fungus Botryosphaeria kuwatsukai in Korea.

• Horticultural Science & Technology
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• v.30 no.1
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• pp.50-55
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• 2012

This study was carried out to evaluate the effect of pre-harvest factors on fruit quality and the incidence of storage disorders in 'Fuji' apple during CA storage. Incidence of storage disorders varied, depending on the growing regions, field conditions, and altitude of the orchards. Results indicated that fruit maturity may play a crucial role in the incidence and severity of flesh browning and watercore. The incidence of these storage disorders increased with fruit maturity until 180 days after full bloom (DAFB). In addition, occurrence of watercore was correlated with the incidence of flesh browning during CA storage. The incidence of flesh browning was positively correlated with the sum of the diurnal temperature range from September through October and amount of precipitation from August to October in 1996-1999 growing years. These results suggested that 'Fuji' apple should be harvested no later than 180 DAFB because the late harvested fruits were prone to development of watercore which was correlated with the incidence of flesh browing during CA storage in Korea.

• Food Science and Preservation
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• v.14 no.1
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• pp.105-108
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• 2007

This study tested customer preferences for "Fuji" apples stored using functional modified atmosphere film (30m) for 16 weeks at $0^{\circ}C$. Customers were 20-60 years of age and lived in either Seoul or Geochang. The freshness, texture, chewiness, and purchase attractiveness of apples in film packaging were judged to be significantly higher than control apples by those aged 20-29 years. The freshness, sourness, flavor, and purchase attractiveness of apples in film packaging were judged to be significantly higher than control apples by those aged 30-39 years. The flavor and sweetness of apples in film packag ing were judged to be significantly higher than control apples by those aged either 40-49 or 50-59 years (${\alpha}=0.05$). In the overall preference tests, apple freshness (P=0.0011), apple flavor (P=0.0002), and apple purchase attractiveness (P=0.0018) of apples in film packaging were judged to be significantly better than control apples by all age groups (those aged 20-59 years).

• Food Science and Preservation
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• v.13 no.4
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• pp.427-431
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• 2006

The research was conducted to measure the effect of pressure cooling of 'Fuji' apple during of 24 weeks. Weight loss in pressure cooling was lower than control at 24th week, and firmness in pressure cooling was higher than control. Titratable acidity in control and pressure cooling was 0.0823% 0.1103% in 24 weeks, respectively. Soluble solid content (SSC) in pressure cooling were higher than control. Decayed rate in control and pressure cooling was 46.4% 34.5% in 24 weeks, respectively. Total ascorbic acid contents were decreased in control and pressure cooling during 24 weeks. Therefore, it could be suggested that pressure cooling is more effective than control in storage of 'Fuji' apple.

• Korean Journal of Environmental Agriculture
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• v.41 no.3
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• pp.199-205
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• 2022

BACKGROUND: The freezing injury by pruning can be reduced by suspending pruning work when severe cold weather (-23 to -49℃) is forecast. Minimum air temperature of the study area, Gunwi region at February 3, 2012 was -21.9℃, and the subzero temperature continued until April 8, 2012. This study was conducted in two years to investigate the effect of delaying winter pruning until full bloom on shoot growth and fruit quality of 'Fuji'/M.9 apple trees. METHODS AND RESULTS: The time of pruning were March 26 for dormant, April 3 for bud break, and May 2 for full bloom. The winter pruning at full bloom significantly reduced fruit weight for two years compared with the control (winter pruning at dormant), and shoot growth was reduced only in the following year. There was no significant effect of delaying winter pruning at bud break on soluble solid content, fruit red color, return bloom, and pruning weight for two years compared with the control. CONCLUSION(S): These results indicated the delaying winter pruning at bud break of 'Fuji'/M.9 apple tree did not offer any disadvantage over comparable dormant pruning, since the fruit quality was not affected. The delayed pruning at full bloom resulted in decreased fruit weight, though shoot growth, fruit quality, and return bloom were not affected by the delayed pruning. So, the delayed pruning should be considered carefully only for the fruit tree orchards in diseases.

• Korean Journal of Environmental Agriculture
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• v.42 no.2
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• pp.104-111
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• 2023

As apple trees mature, it is important to maintain good light distribution within the canopy to produce marketable fruits. Tree thinning is the selective removal of a proportion of trees growing in the orchard to provide more growing space and a good light environment for the remaining trees. This study was conducted over 3 years (14-16 years after planting) to investigate the influence of tree thinning on vegetative growth, yield, fruit quality, and blooming in the 14 years old slender spindle 'Fuji'/M.9 apple trees planted with the tree space of 3.2×1.2 m. The trees were placed in a control group (no thinning; 260 trees per 10 a) or a tree thinning group (thinned 50% of the control; 130 trees per 10 a). The tree thinning successfully improved light penetration, yield per tree, fruit red color, and yield efficiency for 3 years, and the tree thinning controlled the occurrence of biennial bearing. However, tree thinning significantly decreased accumulated yield per 10 a compared with the control. The vegetative growth, yield per tree, soluble solid contents, and blooming were not clear by the occurrence of biennial bearing in the control. These results indicated that tree thinning was a good method for improving light penetration and preventing biennial bearing in the old 'Fuji'/M.9 high-density apple orchards.

• The Plant Pathology Journal
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• v.19 no.6
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• pp.269-273
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• 2003

A total of 57 isolates of Colletotrichum gloeosporioides were recovered from diseased tissues of Hall's crab apple (Malus haliana), 3 cultivars of edible apple (M. pumila var. dulcissima), red pepper (Capsicum annum), and grapevine (Vitis vinifera) fruits. All isolates showed strong virulence on their own host plants. Isolates from edible apple exhibited high level of cultivar specificity in pathogenicity tests. Ten isolates from apple cultivar 'Fuji' were virulent on 'Jonathan' and 'Rall's Genet'. However, 12 isolates from 'Jonathan' and 'Rall's Genet' were not virulent on 'Fuji'. Among the 24 isolates from red pepper, only seven and two isolates were infective on edible apple and grapevine fruits, respectively. All six isolates from grapevine were only virulent on their own host. These isolates were grouped into five vegetative compatibility groups (VCGs), A, B, C, D, and E, by demonstrating heterokaryosis through complementation using nitrate-nonutilizing (nit) mutants. Among them, isolates belong to VCG-A and VCG-D accounted for 24 and 17 isolates； those in VCG-A exhibited wide host range involving Hall's crab apple, all three edible apple cultivars, and red pepper. On the other hand, isolates of VCG-D and VCG-E showed limited host range specific to red pepper and grapevine, respectively. Taken together, the data suggest that among C. gloeosporioides isolates, the concepts of pathotype and/or forma specialis may exist, and that three is a relationship between host specificity and VCG grouping among C. gloeosporioides isolates.