• Korean Journal of Agricultural Science
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• v.44 no.1
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• pp.23-29
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• 2017

This study was conducted to explore which pollen type could be an effective pollen source for self-incompatible 'Niitaka' pear (Pyrus pyrifolia Nakai), when different pollinizers were to be applied. The pollens of five different pears with similar flowering times were applied to bagged 'Niitaka' flowers grown in Cheonan city, Korea. Pollen types used were of different origins including Korean pears ('Wonhwang' and 'Chuhwangbae'), Japanese pears ('Chojuuro' and 'Okusankichi'), and Chinese pear ('Yali'). Results show that the amount of pollen produced by flowers of each cultivar was the largest in Korean pear 'Wonhwang' (234 g/100 flowers) and the smallest in Japanese pear 'Okusankichi' (126 g/100 flowers). A high proportion of large fruits (> 600 g), 71.4% of total production, was found in the fruits treated with 'Yali' pollen. However, these fruits showed an unfavorable external appearance. Based on individual fruit width differences, 'Chojuuro' treatment produced the smallest difference in fruit diameters (3.2 mm) and 'Yali' treatment' gave the largest (4.8 mm). Also, the difference in fruit length was the largest in 'Yali' (7.5 mm), which also produced the most uneven fruits among the pollinizers used. Meanwhile, the use of pollens of 'Wonhwang' and 'Chuhwangbae' improved productivity by increasing the fruit shape index and the ratio of bigger fruits in total production. Moreover, those pollens also decreased the development of lenticels on fruit skins which gave them a smoother appearance.

• Korean Journal of Agricultural Science
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• v.38 no.3
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• pp.405-411
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• 2011

In this study, we evaluated the changes of fruit quality indices during fruit development and ripening in Korean new pear cultivar 'Wonhwang' and 'Whasan' to determine appropriate harvest time and to enhance the marketability. The fruit of each cultivar harvested from 100 days after full bloom (DAFB) to 135 and 150 DAFB in 'Wonhwang' and 'Whasan', respectively. The fruit growth of both cultivars showed a typical single sigmoidal pattern. Flesh firmness of two cultivars decreased continuously with fruit development and ripening, reaching a final level of about 2.6 kgF at harvest stage. The starch content of fruit sap was much higher in the fruits of early development stage than the later stage of fruit ripening. In 'Wonhwang' pears, the starch level decreased coincide with fruit ripening (130 DAFB), while that of 'Whasan' decreased from very early stage of fruit development (120 DAFB), 30 days before full ripe. 'Whasan' pear showed much lower acidity level of about 0.13% during fruit development and ripening period compared with that of 'Wonhwang'. Therefore, the ratio of soluble solids to total acidity (TSS/acid) increased gradually with fruit development and ripening, reaching a final level of 80 and 98 in 'Wonhwang' and 'Whasan', respectively. There were no climateric rise of fruit respiration during fruit ripening periods in two oriental pear cultivar. The changes of skin color difference including hunter vale $a^*$ which means loss of green color occurred only after onset of ripening in two cultivars.

• The Korean Journal of Community Living Science
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• v.21 no.1
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• pp.71-79
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• 2010

This study was conducted to develop fresh-cut and processed pears. After treatment of citric acid (1%) or N-acetylcysteine (0.2 M), and co-treatment of citric acid (1%) and N-acetylcysteine (0.2 M) into the pears c.v. 'Wonhwang', the quality changes of pears during cold storage ($1^{\circ}C$) for 10 days were investigated respectively. Pear quality and the taste of pears increased much more in those treated with anti-browning agents than those in the control group at 10 days after anti-browning treatment and cold storage. Changes in Hunter b values of pears treated with 0.2 M N-acetylcysteine were insignificant. Those with Polyphenol oxidase (PPO) activity and ethylene production were had the most decreased effects and those with the phenolics compound contents were the most lowered. Firmness of fruits increased in treatment of 0.2 M N-acetylcysteine + 1% citric acid solution. The amount of respiration decreased in the application of 1% citric acid solution. Consequently, fruit freshness can be maintained more effectively by the treatment of the anti-browning agent compared to non-treatment, even if the effectiveness were different among different kinds of anti-browning agents.

• Microbiology and Biotechnology Letters
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• v.37 no.3
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• pp.213-218
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• 2009

The goal of this study was to develop new functional pear wine using six Asian pears (Pyrus pyrifolia, Nakai), namely Wonhwang, Niitaka, Whangkeumbae, Whasan, Gamcheonbae and Chuwhangbae. To select optimal yeast and pear, we investigated the physicochemical properties of the pear wines from fermentation of musts of six pear cultivars at $25^{\circ}C$ for 7 days by several yeasts. $11.2%{\sim}12.4%$ of ethanol from musts of 'Wonhwang', 'Whangkeumbae' and 'Whasan' were produced by Saccharomyces cerevisiae K-7 and 12.8% of ethanol was also produced from 'Niitaka' by commercial Saccharomyces cerevisiae C-2. 9.9% and 11.4% of ethanol were produced from musts of 'Gamcheonbae' and 'Chuwhangbae' by Saccharomyces cerevisiae KCTC 7904, respectively. Among several pear wines, Niitaka pear wine showed the best acceptability in the sensory evaluation, and Niitaka pear wine and Whangkeumbae pear wine showed 31.1% and 27.8% of antihypertensive angiotensin I-converting enzyme(ACE) inhibitory activity, respectively. However, the other functionalities were not detected or very low. Furthermore, Niitaka-strawberry mixed fermentation wine was showed the excellent acceptability and high antihypertensive ACE inhibitory activity of 64.9%.

• Food Science and Preservation
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• v.23 no.2
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• pp.174-179
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• 2016

This study was to prepared vinegars using three kinds of pear cultivar with different maturities, 'Wonhwang', 'Niitaka', and 'Chuhwangbae', and investigate their physicochemical characteristics and antioxidant activities. Result showed that the firmness of 'Wonhwang' was much lower than other pear cultivars. No significant difference in soluble solid content was found among three pear cultivars. The total acidity of 'Chuhwangbae' pear vinegar was 4.89~7.98%, which was higher than that those of 'Wonhwang' and 'Niitaka' vinegars. The color of 'Niitaka' vinegar had a lower lightness and redness values, but a higher yellowness value, compared with the other two vinegars. The free sugar contents were mainly composed of fructose, glucose, and sorbitol, with the greatest content of sorbitol in all three peer vinegars. The total phenolics and flavonoids contents were 35.2~55.3 and 8.4~14.4 mg/100 mL, respectively. Antioxidant activity had a positive correlation with total phenolic contents. The DPPH free radical scavenging and $ABTS^+$ radical scavenging activity were 45.0~62.1% and 73.8~78.2%, respectively. From these results, we confirmed that immature pear cultivars such as 'Wonhwang', 'Niitaka' and 'Chuhwangbae' could be used as a raw materials to prepare vinegar regardless of maturity.

• Korean Journal of Agricultural Science
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• v.40 no.2
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• pp.79-86
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• 2013

We investigate the effect of preharvest spray of aminoethoxyvinylglycine (AVG), an inhibitor of ACC synthase activity, on fruit quality of 'Wonhwang' pear (Pyrus pyrifolia Nakai). And the effects were compared with ethephon which releasing ethylene to elucidate treatment efficacy of ethylene biosynthesis inhibitor on Asian pears. Chemicals were sprayed on 30 days before harvest with AVG (75 and 150 mg/L) and ethephon (100 mg/L), respectively. Highest flesh firmness during 21 days of shelf-life at $25^{\circ}C$ after 30 days of cold storage was attained in the fruit treated with 150 mg/L AVG (26.5N) when compared with untreated control (16.7N), while the fruits treated with 100 mg/L ethephon completely lost their marketability within 14 days of shelf-life by mass drop of firmness down to 11.6N. Low incidence of physiological disorders including pithiness and core browning were attained at the fruits treated with 150 mg/L AVG when we compared with untreated control. No occurrence of mealiness found in the fruits treated with AVG but ethephon treated fruits showed 36.4% during 14 days of shelf-life. Consequently, AVG spray at the concentration of 150mg/L on Asian pear 'Wonhwang' fruit regarded as useful preharvest management approach for keeping quality during marketing period after simulated exportation.

• Journal of Plant Biotechnology
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• v.43 no.4
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• pp.486-491
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• 2016

The aim of this research is to establish shoot regeneration system for 'Wonhwang' pear (Pyrus pyrifolia L.) using various concentrations of 1-Naphthaleneacetic acid (NAA) 0.01, 0.05, 0.1, 0.5 mg/L in combination with benzylaminopurine (BA) 3, 5, 10 mg/L. Medium containing 4.4 g/L of Murashige and Skoog (MS) medium with vitamins containing 8 g/L of plant agar and 30 g/L of sucrose with NAA 0.05 mg/L and BA 3 mg/L showed 13.3% of shoot regeneration rate. 'Wonhwang' showed no root growth on existing rooting media of P. pyrifolia cv. Niitaka, 'Whang-keumbae' and 'Bae Yun No. 3'. We evaluated the effect of concentration and kinds of plant growth regulators and carbon source to establish efficient rooting condition for 'Wonhwang' pear. In the result of using various concentrations of NAA 0.5 mg/L and 1.0 mg/L in combination with indolebutyric acid (IBA) 3, 5, 10 mg/L, rooting rate of 24% was observed using 1/4 Linsmaier and Skoog (LS) medium supplemented with 7.5 g/L glucose as carbon source and IBA 1.0 mg/L with NAA 1.0 mg/L.

• 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.32 no.2
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• pp.193-201
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• 2014

We investigated the effect of preharvest spray of aminoethoxyvinylglycine (AVG) on the fruit quality and incidence of physiological disorders during shelf-life of 'Hanareum' and 'Wonhwang' pear (Pyrus pyrifolia Nakai). AVG applications (0, 75, 150 and $300mg{\cdot}L^{-1}$) made 30 days before anticipated harvest of respective cultivar. AVG did not influence the fruit development and quality parameters including starch content, soluble solids and acidity at harvest time in two pear cultivars although the flesh firmness of the fruits treated with $300mg{\cdot}L^{-1}$ AVG were higher than that of control in 'Hanareum' pear. Among the three AVG concentrations, only $300mg{\cdot}L^{-1}$ AVG showed effectiveness on maintaining flesh firmness in 'Hanareum' pear during shelf-life. Meanwhile, competitive high flesh firmness was attained in 'Wonhwang' pear treated with $150mg{\cdot}L^{-1}$ AVG (27.7 N) and $300mg{\cdot}L^{-1}$ AVG (28.2 N) when compared with untreated control (17.8 N) during 21 days of shelf-life at $25^{\circ}C$. AVG did not cause any significant difference at skin color development relative to control in two pear cultivars. AVG decreased ethylene production and respiration rate at $300mg{\cdot}L^{-1}$ level in two pear cultivars during the entire shelf-life. During shelf-life, low incidence of physiological disorders including internal and core browning and mealiness were attained in the fruits treated at $300mg{\cdot}L^{-1}$ AVG in two cultivars when we compared with the untreated control.

• Korean Journal of Agricultural Science
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• v.40 no.2
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• pp.107-113
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• 2013

We tested fruits quality and skin coloration of two pear cultivar 'Wonhwang' and 'Whasan' produced by bagging with different kinds of paper bags in the Cheonan area, Chungnam Province, Korea. The fruits were bagged at 35, 45, 55 or 65 days after full bloom (DAFB) with 3 kinds of double layer paper bag which consisted of grey color, yellow color and newspaper for outer layer. The great extent of light interruption was observed in grey colored outer paperbag among three kinds of paperbag which showed only 0.46% of lowest light transmittance when compared with 43.7% and 40.0% of yellow paper and newspaper, respectively. The development of skin redness ($a^*$) increased with the delay of bagging time in two pear cultivars. But the fruits treated at 65 DAFB showed uneven coloration and excessive development of redness which represented low fruit external appearance value. Uniform flesh firmness was attained at the fruits bagged with grey outer color paperbag regardless of bagging time, although the fruit quality indices including soluble solids and titratable acidity did not change significantly by using different kind of fruit bags and bagging time in two pear cultivar. Based on our results, it was explained that the grey-colored fruit bag had positive effect on the development of skin coloration without any detrimental effect on fruit quality factors in 'Wonhwang' and 'Whasan' pears.