• Horticultural Science & Technology
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• v.31 no.6
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• pp.666-676
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• 2013

The study was carried out to examine the initial point of dormancy, breaking time of internal dormancy, and to find out the accumulated hours of low temperature (under $7.2^{\circ}C$ from $0.0^{\circ}C$ to $7.2^{\circ}C$) for bud-breaking. Over-all, the chilling requirement for breaking of internal dormancy in the commercial apple cultivars ('Fuji' and 'Tsugaru') and apple cultivars bred in Korea ('Hongro', 'Sunhong', 'Honggeum', 'Hongan', 'Hongso', 'Gamhong', 'Summer dream') at the Gunwi region for 4 years (from 2009 to 2012) was investigated. Also, the breaking time of internal dormancy in the field at the Gunwi region and the breaking time of dormancy if air temperature of Gunwi region rises $4^{\circ}C$ higher than the current one were investigated using the same data. The initial point of dormancy was set at the time when the lateral bud breaking did not occurred (when heading back cutting was done in the middle of terminal shoots). The occurrence of the breaking of internal dormancy was decided if the breaking of the terminal bud of bourse shoot occurred within 15 days or not in growth chamber. About 100 bourse shoots were collected by cultivar classification in early December every year and were stored at $5.0^{\circ}C$, and they were placed in growth chamber at one week interval. The chilling requirement of cultivars was expressed in accumulated hours in the field and in the growth chamber under $7.2^{\circ}C$ and $0.0-7.2^{\circ}C$ from the initial point of dormancy to the breaking time of internal dormancy. The results showed that the initial point of dormancy in selected cultivars could occur at the end of September. The breaking time of internal dormancy could occur from the end of January to the early of February. The accumulated hours under $7.2^{\circ}C$ for breaking of internal dormancy were 1,600-2,000 hours, while those of $0.0-7.2^{\circ}C$ were 1,300-1,800 hours. In comparing the different apple cultivars, the chilling requirement of the early flowering cultivars seemed lower than that of the late-flowering cultivars. Based on these results, if the air temperature of Gunwi region rises about $4.0^{\circ}C$ higher than the current one, the breaking time of internal dormancy will be delayed by 2-4 weeks.

• Horticultural Science & Technology
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• v.17 no.3
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• pp.337-340
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• 1999

In order to evaluate stored apple pollen viability, in vitro germination test was performed on a microscope slide coated with the culture medium containing fluorescein diacetate (FDA). However, the inclusion of FDA to the culture medium declined pollen germination. Alternatively, the fluorochromatic reaction procedure was tested. The procedure involved dusting pollen grains onto drops of 10% sucrose solution containing 0.002% FDA and allowing them to accumulate fluorescein. Within 30 min after the fluorochromatic reaction, viable pollen grains clearly fluoresced under ultraviolet light. Both the in vitro germination test and the fluorochromatic reaction procedure revealed that stored apple pollen viability was not considerably decreased over storage up to at least 39 months. Of the cultivars examined by both methods, 'Fuji' and 'Senshu' pollen viability was highest, 'Tsugaru' was intermediate, and 'Jonagold' was lowest. The fluorescing percentages appeared approximately comparable to the germination percentages except for the 'Senshu' pollens stored for 3 months, although the fluorescing percentages was slightly higher than the germination percentages. Strong and highly significant correlations were found between the two methods. It can thus be concluded that the fluorochromatic reaction procedure provides a convenient and reliable evaluation of stored apple pollen viability.

• Korean Journal of Agricultural and Forest Meteorology
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• v.6 no.3
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• pp.170-176
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• 2004

This study was carried out to establish a spatial decision support system for evaluating climatic aspects of a given geographic location in complex terrains with respect to the quality apple production. Monthly climate data from S6 synoptic stations across South Korea were collected for 1971-2000. A digital elevation model (DEM) with a 10-m cell spacing was used to spatially interpolate daily maximum and minimum temperatures based on relevant topoclimatological models applied to Jangsoo county in Korea. For daily minimum temperature, a spatial interpolation scheme accommodating the potential influences of cold air accumulation and the temperature inversion was used. For daily maximum temperature estimation, a spatial interpolation model loaded with the overheating index was used. Freezing risk in January was estimated under the recurrence intervals of 30 years. Frost risk at bud-burst and blossom was also estimated. Fruit quality was evaluated for soluble solids, anthocyanin content, Hunter L and A values, and LID ratio, which were expressed as empirical functions of temperature based on long-term field observations. AU themes were prepared as ArcGlS Grids with a 10-m cell spacing. Analysis showed that 11 percent of the whole land area of Jangsoo county might be suitable for quality 'Fuji' apple production. A computer program (MAPLE) was written to help utilize the results in decision-making for site-selection of new orchards in this region.

• Korean Journal of Food Science and Technology
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• v.31 no.5
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• pp.1275-1282
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• 1999

The quality changes by storage conditions were examined in order to establish the optimum CA storage conditions of unbagged and bagged 'Fuji' apples. The weight retention rate of apples was higher in CA than air storage, but there was no significant difference among CA conditions. Bagged apples had higher weight than unbagged apples under the same condition. The loss of flesh firmness, titratable acidity and green color of apples was retarded more effectively in 1% $O_2$ than 3% $O_2$ storage, and in $0^{\circ}C$ and 3% $CO_2$ than $2^{\circ}C$ and 1% $CO_2$ with 1% $O_2$ Titratable acidity tended to decrease more rapidly in bagged than unbagged apples. Soluble solid was not affected by storage conditions. Internal browning was developed within 2 months in 1% $O_2$ and 3% $CO_2$ storage, but there was no significant difference according to storage years and bagging treatment. At the sensory evaluation, unbagged apples were rated as higher quality than bagged apples after 8 months storage, and the hardness, juiciness, acidity and overall acceptability of apples stored in 1% $O_2$ were Higher than those in 3% $O_2$ but those of apples stored in 1% $O_2$ were not affected by $CO_2$(1, 3%) and temperature(0,\;$2^{\circ}C)$ differences. Above results suggest that the optimum CA storage condition of 'Fuji' apples is $0^{\circ}C,\;1%\;O_{2}+1%\;CO_2$.

• Korean Journal of Agricultural and Forest Meteorology
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• v.16 no.2
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• pp.131-136
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• 2014

This study was carried out to determine the effects of wind speed on physiological responses in 'Fuji' apple (Malus pumila Miller). Two levels of wind blowing (3 and $5m{\cdot}s^{-1}$) were produced by large electric fans. Photosynthetic rate was reduced by one-way wind blowing treatment at $5m{\cdot}s^{-1}$, compared to the mild wind control, and this reduction was more obvious with stronger wind and increasing duration of wind application. The reduction in photosynthesis by the wind treatments was correlated with that in the proportion of opened stomates and stomatal conductance. The one-way wind treatment at $5m{\cdot}s^{-1}$ caused a leaf browning and leaf fall, and this negative effect became more serious with increasing time of exposure to the wind treatments. The sap flux through stem increased in all wind treatments compared to the natural mild wind.

• Journal of Environmental Science International
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• v.19 no.10
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• pp.1293-1299
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• 2010

This study was carried out to compare and analyze the effect of Korean effective microorganism(KEM) and seafood amino acid fertilizer(SAF) application on apple on functional substances of fruit. Vitamin C in fruit of control and KEM/SAF treated were 29.3 and, 39.8 mg, respectively. Also active oxygen scavenging ability of those treatments measured with DPPH method were 40.6 and 54.1%, respectively. Vitamin E contents of those treatments were 2.51 and 2.50 mg, respectively. Sitosterol, a phytosterol, contents of those treatments were 4.79 and 5.41 mg, respectively. Proportion of sugars, fructose, glucose, and sucrose in the fruit of control were 36.1, 15.3 and 17.8%, respectively. Those of the fruit of KEM/SAF treated were 45.9, 13.2 and 18.8%, respectively. Malic acid contents of control and KEM/SAF treated fruits were 53.7 and 43.8%, respectively.

• Journal of Plant Biotechnology
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• v.37 no.4
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• pp.408-413
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• 2010

The paper reviewed research status and outlook of genetic transformation in fruit trees in Korea. Genetic transformation has been long considered as an alternative technique overcoming limitation of conventional breeding and conducted since early 1990's. An efficient genetic transformation was established with major cultivars of apple, even in Fuji and Gamhong, and some transgenic apple plants have been transferred into the greenhouse for further analysis of gene expression. A few successes of genetic transformation have been reported and application to a variety of cultivars tried in citrus and kiwifruit. Successful genetic transformation has not been reported in the other fruit trees including grapevine, yet and it is considered being at the level of research. Those factors including replacement of antibiotics as a selective agent, use of transgenic rootstocks and manipulation of gene expression at proper parts and developmental stages have been prerequisites for the rapid commercialization of transgenic fruit plants.

• Horticultural Science & Technology
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• v.16 no.1
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• pp.27-29
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• 1998

Artificial pollination (AP) and gibberellin A4+7 plus benzyladenine (promalin) were applied alone and together. AP was applied at 10% flowering time with 'Senshu' pollen (Malus domestica cv. Senshu). 12mg/L promalin was applied at 0, 10 and 20 days after falling of central flowers, respectively. In promalin treatment with or without AP application methods, fruit length, weight and length/diameter (L/D) were higher than those of control and AP. However, in AP and AP+ promalin application, the number of seeds and seed weight were higher than those of control and promalin. In AP+ promalin treatment, 78.6% fruits showed their uniform fruit shape and so significantly enhanced fruit uniformity compared to other treatments. Also cortex and core thickness of fruits were greater at the apex than that of other treatment. Fruit with L/D ratio over 0.87 were highly produced by applications of AP+promalin and promalin than control and AP only. 'Fuji' apples in good shape can be produced by using of AP + promalin together.

• Horticultural Science & Technology
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• v.19 no.2
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• pp.174-178
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• 2001

Absorption potential of oak charcoal was estimated using simulated static and dynamic systems to establish a model for practical application of the charcoal in modified atmosphere (MA) packaging and during the storage of 'Fuji' apples. Practical MA packaging was performed using $60{\mu}m$ PE film zipper bags in which five apples were placed. Absorption potential of oak charcoal was $58.4{\mu}L/100g$ charcoal for ethylene and 583 mg/100 g charcoal for carbon dioxide. Effects of enclosing a 100 g-charcoal packet inside a MA package seemed not to last long enough for quality maintenance of 'Fuji' apples stored at $0^{\circ}C$ for three months. During extended storage, ethylene and $CO_2$ levels were not significantly reduced by charcoal treatment. Nevertheless, absorption of carbon dioxide appeared to alleviate the incidence of $CO_2$-related internal browning disorder. Modelling study of practical storage and marketing procedure indicates that 0.19 kg charcoal/day is required to offset $CO_2$ production from 15 kg of apples at $0^{\circ}C$. The amount of charcoal should be increased to 3.10 kg/day if ethylene is a target gas. From the practical point of view, the results suggest that charcoal could be used only for small unit packages for a short period.

• Korean Journal of Soil Science and Fertilizer
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• v.11 no.1
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• pp.9-16
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• 1978

In order to establish a better combination of nutrients of complex fertilizer for apple tree a boron-enriched complex fertilizer ($N-P_2O_5-K_2O-B_2O_5-MgO$: 10 10-0.2-2.0) was compared with various treatments using urea superphosphate, potash muriate, usual complex fertilizer (22-22-11) and borax in its effect on the various growth status such as total leaf weight per tree and shoot growth of dwarf Fuji (1 year old) and super type Starcreamson (3 year old) grown at comparatively poor soils. For Fuji grown on sandy red soils the boron-enriched complex fertilizer (BC) was best and followed by-usual complex fertilizer NPK only, NPK only+Boron, BC+high boron (17times) and no phosphorus in the order. For Starcreamson grown on heavy clayey soils CB+high boron and phosphorus was best and followed by BC, usual complex fertilizer, NPK only, BC+high boron, NPK+boron and no phosphorus in the order. Without compost in the poor heavy clayey soil the growth was worse with high boron and best with NPK+boron and followed by BC Growth was poor with high boron alone but better with phosphorus and high boron, and it was thought that boron was effective when it was distributed in soil with N.P.K. Fertilizer response of apple tree was well appeared on leaf length, new shoot length and total leaf weight per tree. Suitable formulation of a boron-enriched complex fertilizer for apple tree appeared as 10-20-10-0.6 ($N-P_2O_5-K_2O-B_2O_5$) for poor fields and fields with moderate fertility. Chemical analysis of leaves suggested Mg effect on the increase of leaf weight. Effect of Fe was similar to thatof of Mg.