• Journal of Bio-Environment Control
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• v.26 no.4
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• pp.378-385
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• 2017

In this study, we evaluated the changes of fruit quality indices during fruit development and ripening in Korean new pear cultivar 'Changjo', developed from a cross between 'Tama' and '81-1-27' ('Danbae' ${\times}$ 'Okusankichi') in 1995 and named in 2009, to determine appropriate harvest time and to enhance the market quality and broaden the cultivation area. The fruits of 'Changjo' pears harvested from 132 days after full bloom (DAFB) to 160 DAFB. Fruit growth and quality indices were monitored at 1 week interval by measuring fruit weight, length, diameter, firmness, and taste related quality indices. The calculated fruit fresh weight increased continuously with fruit development and reached to an average of 594g on Sep. 20 (160 DAFB). The ratio of length to diameter declines as fruit maturation progress, resulting in 0.898 for ripe fruit stage as a round oblate shape. Flesh firmness of 'Changjo' pears showed over 30N until 153 DAFB and then decreased abruptly with fruit ripening, reaching a final level of about 26.44N on 160 DAFB. Starch content of fruit sap was also decreased abruptly after 146 DAFB which decreased almost half of the fruits harvested at 139 DAFB. In parallel with the decrease of flesh firmness, ethanol insoluble solids (EIS) content decreased sharply with fruit ripens, only 50% of EIS was detected on the fruits harvested on 160 DAFB when compared to that of the fruits harvested on 139 DAFB (Aug. 30). The maximum value of soluble solids contents was observed in the fruits harvested on 153 DAFB, resulting in $14.2^{\circ}Brix$. The changes of skin color difference $a^*$ which means loss of green color occurred only after 139 DAFB, coincide with the decrease of SPAD value of the fruit skin. The sugars of the 80% ethanol soluble fraction consisted mainly of fructose, sorbitol, glucose and sucrose, also increased during maturation and ripening. Fructose and sucrose contents were larger than those of glucose and sorbitol in flesh tissues. These results were explained that stored starch is converted to soluble sugars during fruit maturation, mainly in fructose and sucrose increasing the sweetness of this cultivar. Total polyphenols were increased up to middle of fruit maturation (146 DAFB) and then decreased continuously until the end of fruit maturation. Consequently, our results suggested that the commercial harvest time of 'Changjo' pears should not be passed 153 DAFB and late harvest of this cultivar would not good for quality maintenance during shelf-life. As a result of the post-harvest low-temperature acclimation experiment during the short-term transportation period, fruits harvested at 146 DAFB tended to maintain higher firmness after 14 days of simulated marketing at $25^{\circ}C$ compared to fruits harvested at 153 DAFB regardless of temperature set. And, the slower the rate of decrease to the final transport temperature of $5^{\circ}C$, the higher the incidence of internal browning and ethylene production. Therefore, in order to suppress the physiological disorder and to maintain the fruit quality when exporting to Southeast Asia in the 'Chanjo' pears, it is desirable to lower the temperature of the fruits within a short time after harvest and to set the harvest time before 146 days after full bloom.

• KOREAN POULTRY JOURNAL
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• v.35 no.6 s.404
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• pp.67-71
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• 2003

• KLA journal
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• v.51 no.9
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• pp.22-32
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• 2010

• Horticultural Science & Technology
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• v.31 no.4
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• pp.407-414
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• 2013

This study was carried out to understand the physiological characteristics of 'Manpungbae' (Pyrus pyrifolia Nakai) pears through the seasonal changes of pericarp structure and anatomical differences between bagging and non-bagging treatment, and also fruit quality and peel coloration characteristics at the harvest time. The pericarp at full bloom was consists of outer epidermis, hypodermis, parenchyma cell, and inner epidermis from the exterior. The cell layers from the outer epidermis to vascular bundle increased rapidly 7-10 layers to 18-26 layers from full bloom (FB) to 77 days after full bloom (DAFB) and did not change significantly until maturity. Thus, the cell division period of 'Manpungbae' pear was until 77 DAFB and during this period, the thickness from hypodermis to vascular bundle increased from $73.1{\mu}m$ to $195{\mu}m$ in this period. Stone cells were formed from seven to 21 DAFB and stone cell clusters were formed around 49 DAFB. The cork cell layer was formed between 49 and 77 DAFB. 'Manpungbae' fruit pericarp was consists of 4.5 layers of the cork cell layers and seven layers of hypodermis which has the tannin at harvest time (161 DAFB). Comparison of the fruit enlargement and fruit structure development by bagging or non-bagging showed that 'Manpungbae' fruits without bagging had more than three cork cell layer than those with bagging at maturity. The size of stone cell clusters were varied in two treatments. Fruit weight was higher in the non-bagging treatment but there was no difference in soluble solid contents (SSC) between two treatments. The weight of the 'Manpunbae' fruit was distributed from 301 g to more 900 g and the average fruit weight was 677.2 g at harvest time, and fruits in the range of 551-800 g accounted for 71.6% of total production. The SSC, acidity and SSC/acidity ratio was $10.2-12.1^{\circ}Brix$, 0.10-1.24% and 9.76-14.31 respectively, and the SSC was higher in bigger fruit which had a very higher positive correlation with a fruit weight. However, the fruit firmness tended to be lower with fruit size which had a very higher negative correlation with the fruit weight and SSC. The cork cell layer numbers between yellowish brown and green pericarp were not different significantly, in 3.8 and 3.5 respectively.

• Horticultural Science & Technology
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• v.32 no.1
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• pp.33-40
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• 2014

This study was carried out to understand the physiological characteristics of early-matured 'Hanareum' (Pyrus pyrifolia Nakai) pears through anatomical structure and fruit characteristics and also the changes according to gibberellin (GA) treatment. The pericarp at full bloom consists of outer epidermis, hypodermis, parenchyma cell, and inner epidermis from the exterior and five types of vascular bundle tissues. Cork cell layer was formed at 70 days after full bloom (DAFB) in non-treated fruits and formed at 60 DAFB in GA treated fruits. Cell division period was from full bloom (FB) to 40 DAFB and then fruit enlargement was accomplished by the cell growth. Comparison of the fruit enlargement and fruit structure development by GA treatment or non-treatment showed that cell division of 'Hanaerum' fruits did not affect the GA treatment but fruit enlargement was affected cell growth. Fruit stalk of GA treatment fruits was larger than non-treated fruits from 40 DAFB which correspond to the period of the stop of cell division and 'Hanareum' was regarded GA treatment expedite of vascular bundle tissue growth and relatively increased nutrient transport to fruit. In addition to, average fruit quality between the non-treatment and GA treatment showed that fruit weight was higher in fruits treated by GA but firmness was lower and probably was effected fruit storing in 'Hanareum' pear.

• Horticultural Science & Technology
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• v.34 no.4
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• pp.528-536
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• 2016

This study was conducted to examine the effect of 0.4% of $CaCl_2$, $2H_2O$, $1mg{\cdot}L^{-1}$ of Calmodulin (CaM)-SH, 250-folds of coating agent (WE-36), 1,000-folds of $GA_{4+7}+BA$ and 3 types of paper bagging treatments on russet incidence and fruit quality attributes of 'Gamhong' apple. The pattern of russet occurrence was slightly different for 4 years (from 2012 to 2015) in 'Gamhong' apple. The russet occurrence was lowest in $GA_{4+7}+BA$ treatment at 20 days after full bloom (DAFB), compared with other treatments. The $GA_{4+7}+BA$ treatment increased fruit weight at 20 DAFB, while the other fruit quality attributes were not influenced. The russet occurrence was lower not only in a single bag application than in untreated ones but also in yellow bagging and discolored bagging applications than in a white bagging application. The russet occurrence in a bagging application was lower at 20 DAFB than at 30 and 40 DAFB, while fruit quality attributes were not affected by bagging applications. The russet incidence was lower in $GA_{4+7}+BA$ twice treatments at 20 and 30 DAFB, and calcium coated bag at 30 DAFB after $GA_{4+7}+BA$ treatment at 20 DAFB than in untreated fruit. The rate of russet incidence was lowest at equator region in $GA_{4+7}+BA$ treatment, compared with the other fruit regions. Overall, the results suggest that one and/or two applications of $GA_{4+7}+BA$ (1,000-folds) treatment at 20 DAFB should reduce the risk of russet incidence in 'Gamhong' fruit.

• Journal of Bio-Environment Control
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• v.20 no.3
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• pp.233-240
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• 2011

We evaluated the changes of fruit quality factors and the incidence of physiological disorders during the periods of high temperature environment in 'Wonhwang' and 'Whasan' pears to determine appropriate harvest time for exportation. In 'Wonhwang' pears, the fruits harvested at 130 days after full bloom (DAFB) showed 31.3 and 17.6N of flesh firmness after 5 and 10 days after simulated marketing at $30^{\circ}C$, respectively, while those of the fruits harvested at 135 DAFB lowered to 16.7 or 6.9N, respectively. Whereas, 'Whasan' pear showed higher firmness during 14 days of high marketing condition than 'Wonhwang' pears which represented 30.4, 26.5 and 21.6N in the fruits harvested 145, 150 and 155 DAFB, respectively. Higher soluble solid contents and lower acidity values observed in the late harvested fruits in both cultivar along with increased marketing period at $30^{\circ}C$. Late harvested 'Wonhwang' pears showed higher respiration rate and ethylene production than early harvested ones, while those of 'Whasan' pears showed lower values regardless of fruit maturity which represented less than 50% of 'Wonhwang' pears. The incidence of physiological disorders such as internal browning, water soaking, flesh spot decay, core breakdown and pithiness appeared more severely in the fruits of 'Wonhwang' in accordance with the progress of high temperature marketing and fruit maturity. Whereas, those symptoms were occurred only after 14 days of prolonged marketing time in 'Whasan' pears. Consequently, it was needed to pay more attention to determine the ripeness when the fruits exported to the country with high temperature environment, especially in the fruits of 'Wonhwang' pears showing rapid quality loss and severe physiological disorders.

• Horticultural Science & Technology
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• v.18 no.3
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• pp.353-359
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• 2000

'Yumyeong' is one of the most popular peach varieties in Korea. This study was conducted to monitor the developments of cells and tissues, and the changes in sugar contents during fruit growth and development. At bloom, there were two rows of vascular tissues, and the number and the position of internal vascular bundles were consistent during the fruit growth, however, the number of vascular tissues were increased and the distribution was irregular in the flesh tissues. The tissues between the inner integument and the internal vascular bundles showed different development characteristics from other parenchyma cells which were consisted of small and dense cells containing tannins. Such observation suggested that the stone of peach was consisted of inner epidermis and cells in the internal vascular tissues. The outer epidermis consisted of single layer cells at bloom differrentiated into 1-2 layers by horizontal cell divisions on 14 days after full bloom. On 30 days after full bloom, the epidermis was consisted of 5-6 layers by vertical cell divisions. The cell layers consisting the outer epidermis were gradually decreased to 1-2 layers at maturity. The observations on the changes in the epidermis confirmed that some of the cells consisting the hypodermis of peach fruit were originated from the cells of outer epidermis. Tylosis was observed from 35 days after full bloom and the size and number of tylosis were increased until full fruit maturity. The sucrose content showed the tendency of sharp increase from 50 days to 120 days after full bloom then decrease slightly. After when stone hardening ended, other solids showed a gradual decrease tendency from 80 days after full bloom.

• Journal of Korean Society of Forest Science
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• v.110 no.3
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• pp.322-340
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• 2021

Due to climate change and its consequential spring temperature rise, flowering time of Robinia pseudoacacia has advanced and a simultaneous blooming phenomenon occurred in different regions in South Korea. These changes in flowering time became a major crisis in the domestic beekeeping industry and the demand for accurate prediction of flowering time for R. pseudoacacia is increasing. In this study, we developed and compared performance of four different models predicting flowering time of R. pseudoacacia for the entire country: a Single Model for the country (SM), Modified Single Model (MSM) using correction factors derived from SM, Group Model (GM) estimating parameters for each region, and Local Model (LM) estimating parameters for each site. To achieve this goal, the bloom date data observed at 26 points across the country for the past 12 years (2006-2017) and daily temperature data were used. As a result, bloom dates for the north central region, where spring temperature increase was more than two-fold higher than southern regions, have advanced and the differences compared with the southwest region decreased by 0.7098 days per year (p-value=0.0417). Model comparisons showed MSM and LM performed better than the other models, as shown by 24% and 15% lower RMSE than SM, respectively. Furthermore, validation with 16 additional sites for 4 years revealed co-krigging of LM showed better performance than expansion of MSM for the entire nation (RMSE: p-value=0.0118, Bias: p-value=0.0471). This study improved predictions of bloom dates for R. pseudoacacia and proposed methods for reliable expansion to the entire nation.

• The Korea Beekeeping Bulletin
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• s.331
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• pp.44-44
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• 2008