• Korean journal of applied entomology
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• v.59 no.3
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• pp.251-255
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• 2020

In 2019, the ash whitefly, Siphoninus phillyreae (Haliday, 1835), was firstly found on a pear tree in Jinju-si, Gyeongsangnam-do. From occurrence survey, we confirmed that S. phillyreae was occurred in seven cities, Busan, Changwon, Jinju, Gwangyang, Suncheon, Goheung, and Goseong. In addition, seven plants, such as Punica granatum, Pyrus pyrifolia, Cydonia oblonga, Prunus mume, Crataegus pinnatifida, Eriobotrya japonica, Photinia glabra, Pyracantha angustifolia, Lagerstroemia indica, and Malus prunifolia, were detected as hostplants. In this study, we present the first report of this species in Korea and describe the damage caused by S. phillyrease and its taxonomic information.

• Food Science and Preservation
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• v.10 no.3
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• pp.272-277
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• 2003

This study was conducted to determine the minimal processing characteristics as affected by the storage duration of whole Asian pears(Pyrus pyrifolia Nakai cv. Niitaka). Before and after storage for 4 months under air at 0$^{\circ}C$, whole pears were sliced, placed in unsealed plastic bags, and kept for 4 days at 10$^{\circ}C$. Storage of whole pears increased the initial levels of electrolyte leakage, total phenols and browning index and decreased the initial content of vitamin C in pear slices. Slices from stored pears maintained higher respiration rate compared with slices from non-stored pears during keeping. The increase of electrolyte leakage, browning index and microbial number and the decrease of total phenol in slices during keeping were more fast in slices from stored pears than in those from non-stored pears. These results suggest that the minimal processing characteristics of ‘Niitaka’ pears are depending upon storage duration.

• Food Science and Preservation
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• v.17 no.5
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• pp.595-601
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• 2010

We investigated the effects of 1-methylcyclopropene (1-MCP) treatment (0, 0.5, and 1.5 ppm) for 16 hours, followed by storage at ambient temperature, on the qualities of pears (Pyrus pyrifolia c.v. "Hwasan"). Color differences, as measured using the Hunter L, a, and b values, showed the greatest decreases before storage, and 8 weeks after storage, when fruit was exposed to 1.5 ppm 1-MCP. The sensory qualities of c.v. "Hwasan" pears were good until 4 weeks of storage after treatment with 0 ppm 1-MCP, until 6 weeks when 0.5 ppm 1-MCP was employed, and until 7 weeks when 1.5 ppm 1-MCP treatment was performed. Fruit and storage quality in terms of all of hardness, sugar content, PPO activity, respiration amount, and ethylene production increased in the 8 weeks after application of 1.5 ppm 1-MCP. Consequently, it seems that 1-MCP treatment, especially at 1.5 ppm, before storage of pears at ambient temperature, effectively improves the quality of pears of c.v. "Hwasan".

• 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.

• Korean Journal of Organic Agriculture
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• v.27 no.1
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• pp.33-44
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• 2019

This study was initiated to find possibility of substitute of gibberellin acid and to prevent negative girdling effect such as slow growth of 'Niitaka' (Pyrus pyrifolia Nakai) trees, a major pear cultivar, at harvest and at 60-, 90-, and 120-d after storage. Seasonal wiring with 3.0-mm-diameter were applied on the main branch at 70, 80, 90, 110, and 130 days after full bloom (DAF) to compare the fruit quality and storability. Fruit weight and sugar contents were the greatly increased by the wiring treatment at 110 DAF, with the lowest values observed for the wiring at 70 DAF. All the wiring treatments reduced fruit acidity but did not affect fruit firmness. a-value on fruit skin was the highest for wiring at 110 DAF and 130 DAF, advancing fruit ripening. The lowest fruit weight loss was occurred at wiring at 110 DAF. a-value on fruit skin was the highest for wiring at 90 DAF and 110 DAF. Wiring at 80 DAF the most increased floral bud diameter, resulting in the lowest L:D ratio of 1.74 observed. As for the mineral nutrients concentrations of floral buds, the concentration of K (0.63%) and Mg (0.31%) were the highest after 80 DAF wiring treatment, whereas Ca and P concentrations did not differ among treatment plots. The leaf K concentrations was the highest in the 130-day wiring treatment (0.76%) and in the control plot (0.78%), whereas there was no significant difference in the concentrations of either Ca or P among treatment plots. Short periods of wiring increased foliar Mg concentrations. In floral buds, carbohydrates showed a tendency for accumulating at a lower concentrations (7.75%) after 70 DAF wiring treatment, which was a relatively short treatment period. On the other hand, the carbohydrate concentrations in leaves showed a tendency for accumulating at lower concentrations after 130 DAF wiring treatment (2.51%), which is a long treatment period, and in the control plot (2.43%). Wiring increased the size and sugar content of fruits, and influenced fruit storability. For the wiring treatment period was delayed, the carbohydrate concentration in flower buds showed curvilinear correlation and the negative correlation with the carbohydrate in leaf tissue.

• Korean Journal of Organic Agriculture
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• v.23 no.1
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• pp.91-101
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• 2015

'Chuhwangbae' pears (Pyrus pyrifolia Nakai) were investigated on how types of paper bag and harvesting dates influenced on skin blackening before harvest as well as fruit quality after harvest. Experiments included four different types of paper bags (NP/YP, GP/YP, NP/BP, and NP/RP) and five different harvesting dates [160, 170, 180, 190, and 200 days after full bloom (DAFB)]. NP/YP and GP/YP indicated for newspaper- and gray paper-outer bag, respectively, with yellow paper-inner bag of the both. NP/BP and NP/RP indicated for newspaper-outer bag of the both with black paper- and red paper-inner bag, respectively. The NP/YP (newspaper/yellow paper) showed high absorbance and air and water vapor permeability in the bags, while the NP/RP (newspaper/red paper) resulted in poor physical properties in the bags. Fruit enclosed with NP/YP resulted in the absence of skin blackening, but fruit with NP/RP bags had the highest skin blackening (12.7%). Occurrence of skin blackening was concentrated on the middle and calyx end-part of fruit region. NP/RP bag treatment was likely to increase fruit weight, firmness, titratable acidity, and fruit surface color. Harvest at high relative humidity in air increased skin blackening of fruit. Later fruit harvest, such as 190 and 200 DAFB, increased skin blackening, fruit weight, and sugar content while decreasing fruit firmness and titratable acidity.

• Horticultural Science & Technology
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• v.32 no.5
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• pp.645-654
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• 2014

This study was conducted to investigate the effect of 1-methylcyclopropene (1-MCP, $1.0{\mu}L{\cdot}L^{-1}$), a known ethylene action inhibitor, on fruit quality and incidence of physiological disorders during a simulated marketing period at $25^{\circ}C$ for 20 days in early-season Asian pear (Pyrus pyrifolia Nakai) 'Hanareum' that had been treated with 0, 0.5, 1.2 or 2.4% $GA_{4+7}$. Weight loss of stored fruits increased with $GA_{4+7}$ concentration, and the 1-MCP treatment slightly reduced the weight loss rates during the marketing period. Flesh firmness decreased abruptly in all 1-MCP-untreated fruits as the storage period extended to 10 d, whereas the firmness of 1-MCP-treated fruits remained high (> 30 N) during 15 days shelf-life. The effect of 1-MCP was significantly reduced when fruits were subjected to increased GA concentration. Higher soluble solids content and acidity during extended shelf-life were also apparent in 1-MCP-treated 'Hanareum' pears. The L-values (lightness) and hue angles of 1-MCP treated samples were higher than those of controls during 20 days shelf-life, but the a-value (redness) was lower in 1-MCP treated fruits. 1-MCP treatment did not decrease the level of ethylene evolution regardless of $GA_{4+7}$ concentration during shelf-life in early-season Asian pear 'Hanareum'. By contrast, 1-MCP treatment decreased the respiration rate significantly during shelf-life. The efficacy of 1-MCP was greatest in the GA-untreated fruit and was reduced as the $GA_{4+7}$ concentration increased. 1-MCP treatment influenced the severity of physiological disorders including core browning and mealiness: 1-MCP treatment completely blocked the incidence of core browning of during 15 days shelf-life, and reduced the severity of mealiness during 20 days shelf-life regardless of $GA_{4+7}$ concentration. Based on our results, we conclude that the use of $1{\mu}L{\cdot}L^{-1}$ 1-MCP can be of great benefit for maintaining quality and preventing physiological disorders in early-season pear cultivar 'Hanareum' pear, whereas its efficacy decreases with the concentration of $GA_{4+7}$ whereas its efficacy gradually decreases when the concentration of $GA_{4+7}$ paste increased.

• Horticultural Science & Technology
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• v.30 no.5
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• pp.534-542
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• 2012

This study was conducted to investigate the effect of 1-methylcyclopropene (1-MCP) on fruit quality and incidence of physiological disorders for keeping freshness during marketing period in Asian pear (Pyrus pyrifolia Nakai) 'Wonhwang' and 'Whasan'. Fruits were treated with $1{\mu}L{\cdot}L^{-1}$ 1-MCP for 12 hours at $25^{\circ}C$, at two or three stages of ripeness as determined by days after full bloom (DAFB). Fruits were harvested at 130 and 140 DAFB in early season cultivar 'Wonhwang' and 135, 145, and 150 DAFB in mid-season cultivar 'Whasan', respectively. Fruits were stored at $25^{\circ}C$ for 21 days and measured the flesh firmness, weight loss, soluble solids, acidity, ethylene, respiration and severity of physiological disorders at week interval. 1-MCP treatment to 'Wonhwang' pears harvested at 130 and 140 DAFB effectively delayed firmness loss during storage at $25^{\circ}C$. Untreated fruits of 'Wonhwang' pears harvested at 130 DAFB showed 32.3 and 10.1N of firmness after 14 and 21 days of shelf-life at $25^{\circ}C$, respectively, while those of the 1-MCP treated fruits showed 39.4 and 33.1N during same period. In the fruits harvested at 140 DAFB, the firmness of untreated fruit was lowered to 14.8 and 6.6N after 14 and 21 days, respectively, but those of 1-MCP treated fruit were 35.0 and 33.3N, respectively. Whereas, 1-MCP treatment delayed firmness loss only in the fruit harvested late (150 DAFB) in 'Whasan' pears. Higher soluble solids content and acidity during extended shelf-life were apparent in 1-MCP treated 'Wonhwang' pears, while those of 'Whasan' pears were little changed. 'Wonhwang' pears showed a relatively high ethylene production (maximum $0.58{\mu}l{\cdot}L^{-1}$) in the fruits harvested late than early harvested one. 'Whasan' pears showed little amount of ethylene production regardless of extended shelf-life. 1-MCP treatment to 'Wonhwang' pears decreased respiration rate following shelf-life, 42 and 50% reduction were observed at 14 days of shelf-life when compared with those of untreated ones harvested at 130 and 140 DAFB, respectively. No reduction of respiration rate by the treatment of 1-MCP was detected in 'Whasan' pears which showed considerably low respiration rate compared with 'Wonhwang' pears. Harvest time influenced the level of physiological disorders together with extension of shelf-life in both the cultivars. 1-MCP treatment completely blocked the incidence of internal browning of 'Wonhwang' pears harvested at 130 DAFB, and reduced the incidences of pithiness and core browning, while it promoted the flesh spot decay disorder regardless of harvest time. 1-MCP treatment was of little benefit for the prevention of physiological disorders in 'Whasan' pears compared with those of 'Wonhwang'.

• Food Science and Preservation
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• v.17 no.2
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• pp.169-173
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• 2010

Although fruit grown under sustainable farming conditions is believed to be healthier for humans than is fruit grown by conventional cultivation, little scientific information on the characteristics of fruit produced using these two farming systems is available in Korea. Therefore, weinvestigated fruit quality, total polyphenolic contents, and anti-oxidant activities in 'Niitaka' pears grown under sustainable and conventional farming management systems. Treatmentsincluded use of a chitin compost admixed with liquid chitin fertilizer (plot A), and use of a chitin compost admixed with liquid chitin fertilizer treated by infrared radiation (plot B). Plots C and D used conventional management systems. Fruit qualities at harvest differed between both sustainable plots A and B and the conventional plots C and D. The average values of firmness and total polyphenolic content in fruit harvested from sustainable plots were not significantly greaterthan those of fruit grownin conventional plots, after 60 days of storage. Fruit grown in all plots had low polyphenol oxidase (PPO) activity at harvest but this increased during storage. Fruit from sustainable plot B showed an increased electron donating ability compared with fruit grown using the other systems.

• Korean Journal of Food Science and Technology
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• v.35 no.5
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• pp.865-870
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• 2003

The effects of storage atmosphere on the physicochemical and organoleptic properties of Asian pears (Pyrus pyrifolia Nakai cv. Niitaka) were investigated. The pears were stored at $0^{\circ}C$ for up to 8 months under CA conditions (3 kPa $O_2$＋1 kPa $CO_2$, 1 kPa $O_2$+5 kPa $CO_2$, 1 kPa $O_2$+1 kPa $CO_2$) controlled by a static system or air (21 kPa $O_2$+0 kPa $CO_2$). CA conditions retarded the loss of weight, flesh firmness, organoleptic properties (appearance, aroma, sweetness, texture), and the development of injuries in the fruits during storage. Low $O_2$ plus high $CO_2$ conditions maintained the highest flesh firmness. In addition, low $O_2$ reduced injuries more than the other conditions. Skin color (lightness, chroma, hue), soluble solids, titratable acidity, pH and vitamin C were unaffected by storage atmosphere.