• Horticultural Science & Technology
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• v.32 no.1
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• pp.77-83
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• 2014

To improve the breeding efficiency of oriental pear, the inheritance of major fruit traits were analyzed using 4,035 seedlings of 15 cross combinations combined with 13 cultivars. Yearly variation of parental cultivars, broad-sense heritability of the traits, and frequency of seedlings with commercially acceptable characteristics by the mid-parent values were studied. Despite the heritabilities of traits related with pear the fruit texture were different depending on cross combination, the average narrow-sense heritability ($h^2$) for firmness, flesh hardness, flesh density and grit were over 0.6, a relatively high value. However fruit firmness showed different heritability among the cross combination and its value of cross combination between 'Niitaka' and 'Choju' was very low as 0.11. Positive correlation was not observed on fresh hardness, fresh density and grit but observed on firmness between mid-parent value and average value of offspring. Regression of offspring on firmness, fresh hardness, fresh density and grit between mid-parent value and average value of offspring were 0.778, 0.343, -0.273, 0.313, respectively. Frequency distributions of fruit texture in 15 cross combinations of pear seedling was influenced by parental characteristics. When fruit firmness was estimated as low, low ${\times}$ high and high ${\times}$ high values in parental fruits, firmness in their offspring exhibited low, medium and high, respectively. In addition, when parental grit by sensory evaluation were light ${\times}$ light and light-medium ${\times}$ medium-heavy, most of offsprings showed light and medium grit, respectively.

• Food Science and Preservation
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• v.16 no.3
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• pp.317-320
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• 2009

'Niitaka' (Pyrus pyriforia) has been the major cultivar of the Asian pear since the 1970s, and yielded about 70% of pear production in South Korea in 2002. When Chuseok (Korean Thanksgiving Day) is earlier than the fruit maturation period, farmers seek to advance the harvesting date to keep pace with the increase in consumer demand caused by the holiday. However, unripened fruit is of suboptimal marketable value because the flesh has a low soluble solid content, the fruit color is not attractive, and stone volume is high. Compost treatment can enhance soil microbial activity and affect soil chemistry, which may accelerate fruit maturation and allow an earlier harvesting date. Therefore, we examined the effect of 2 years of compost application on the fruit quality of Asian pear trees grown under conventional management conditions. The Hunter "L" and "a" values were higher in compost-treated fruit, which also showed greater sweetness and lower acidity than did conventional fruit. The stone volume was reduced and fruit calcium concentration was increased by compost treatment. Therefore, compost treatment may advance fruit harvesting owing to the increased marketability afforded by attractive skin color, sweetness, and reduced stone volume.

• Journal of the East Asian Society of Dietary Life
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• v.20 no.2
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• pp.239-247
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• 2010

This study was conducted to increase the keeping quality of the minimally processed pear slices during the cold storage. Korean pears, 'Shin-go (Niitaka)', 'Chu-hwang' and 'Won-hwang’ were immersed in 1% ascorbic acid, 0.1% calcium propionate, 1% citric acid, 0.2% N-acetyl cysteine and 0.5 M 4-hexylresorcinol solution for 3 three minutes and then stored at $1{\pm}0.5^{\circ}C$ for 10 days. We have also examined into the firmness and the color difference of pears slices as affected by the application of the anti-browning agents. The firmness of pears slices which that were immersed in 0.1% calcium propionate and 0.2% N-acetyl cysteine solution were not significant at did not differ significantly after 10 days after of cold storage. However, the ${\Delta}E^*$ values of 'Shin-go' slices which that were treated with 0.1% calcium propionate and 0.2% N-acetyl cysteine solution and stored for 10 days decreased by 3.18 and 3.83, when compared with that in of the control, which decreased by 6.36. The ${\Delta}E^*$ values of 'Chu-hwang' slices which that were treated with 0.2% N-acetyl cysteine and 0.1% calcium propionate solution had the slight difference by differed by only 2.09 and 2.14, when compared with that in of the control, which differed by 3.04. The ${\Delta}E^*$ values of 'Won-hwang' slices which that were treated with 1% citric acid and 0.5 M 4-hexylresorcinol were 4.49 and 5.83, respectively, while that in of the control decreased by 8.95. It was assumed that the anti-browning agent treatment had the different activities among varieties of the pear varieties slices, however, application of 0.2% N-acetyl cysteine and 0.1% calcium propionate application had greater the higher antibrowning activity.

• Research in Plant Disease
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• v.15 no.3
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• pp.230-235
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• 2009

Postharvest skin sooty dapple and decay disease of pear fruit often originates at small stain symptoms that occurred during harvest and handling. Experiments were conducted to characterize the effect of timing of application of disease control materials, and to evaluate sequential postharvest applications of fungicides or fungicides and bio-control agents. Fungicides and bio-control agents were increasingly less effective when the period between harvest and application was prolonged. Thiabendazole (TBZ) applied to fruit without artificial wounding or inoculation effectively reduced skin sooty and decay disease when applied within 3 weeks or 6 weeks in 2 years of study. TBZ, Fludioxonil and pyrimethanil were effective in controlling skin sooty and decay disease at artificial wounds inoculated with Cladosporium tenuissimum up to 14 days after inoculation. Application of TBZ at harvest followed 3 weeks later by application of Fludioxonil was superior to application of TBZ at harvest alone. Two bacterial biocontrol agents reduced skin sooty and decay disease at pear wounds inoculated with C. tenuissimum up to 14 days after inoculation with C. tenuissimum, but were ineffective when applied at 28 days after inoculation. Of possible sequential arrangements of fungicide and bio-control treatments, application of the most effective material promptly after harvest generally resulted in the highest level of disease control.

• Korean Journal of Food Science and Technology
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• v.30 no.5
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• pp.1006-1011
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• 1998

Volatile flavor components in three varieties (shingo(niitaka), mansamgil (okusankichi) and chuwhang pears) of Pear (Pyrus pyrifolia N.) were extracted for 24 hours with pentane-diethylether (1 : 1, v/v) using the LLEP (liquid-liquid extraction & perforation). Neutral fraction was separated from the extract and then analyzed by GC-FID and GC/MS equipped with a fused silica capillary column (Carbowax 20M, HP). Individual components were identified by mass spectrometry and their retention indices. The totals of 52, 47 and 22 volatiles were identified in shingo, mansamgil and chuwhang pears, respectively. Ethyl acetate, propyl acetate, hexanal, 1-hexanol, ethyl butanoate, ethyl-3-hydroxy butanoate, ethyl-2-hydroxy propanoate were the main components in each samples, though there were several differeces in composition of volatile compounds. Total contents of volatile components isolated in shingo, mansamgil and chuwhang pears were 6.972, 2.776 and 2.653 mg/kg of pears.

• Korean Journal of Organic Agriculture
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• v.20 no.1
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• pp.37-48
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• 2012

This study was conducted to evaluate the effects of ground cover treatments on the nutrient contribution in a 'Niitaka' pear ($Pyrus$ $pyriforia$) orchard. Treatments included; 1) sod culture, 2) winter cover crop [ryegrass+hairy vetch], and 3) winter [ryegrass+hairy vetch]+summer [greensolgo (sudan grass ($Sorghum$ $bicolor$ L.))+ nemajanghwang (crotalaria ($Crotalaria$ $juncea$ L.)] cover crops. Ryegrass and hairyvetch were seeded with 6.4 kg/10a and 3.0 kg/10a, respectively, on October 17 of 2008, and greensolgo and nemajanghwang were seeded with 2.0 kg/10a and 3.0 kg/10a, respectively, on June 4 of 2009 at a diligent farmer in Boseong in Chonnam. Winter+summer cover crops provided greater amounts of dry weight, followed by winter cover crop and sod culture. The difference of amounts of dry weight from the ground covers affected to the levels of total N, P, and K contents, which were greater nutrient levels than those of recommended nutrient requirement for satisfying 10- to 12-year-old pear tree growth. Greater amounts of dry weight from the ground covers increased organic matter and concentrations of K and Mg in soil. Foliar nutrient concentrations, as an indicator of nutrient status of a tree, were not affected by application of ground cover treatments.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.6
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• pp.721-730
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• 2017

This study determined the optimal mixing ratio of functional materials to enhance the functionality of batter for fish cutlets. An optimal mixing ratio of the hiziki Hizikia fusiformis, fig fruit Ficus carica L. and pear Pyrus pyrifolia Niitaka extracts (HFP extract) of 3:1:1 was found. The physicochemical properties of the mixture were as follows: total phelonic contents of $1187.29{\pm}41.55mg/L$, 1,1-diphenyl-2-picryhydrazyl (DPPH) radical scavenging activity of $61.50{\pm}2.33%$, ascorbic acid content of $23.68{\pm}0.02g/100g$, ${\beta}-carotene$ content of $51{\pm}3.92{\mu}g/100g$, and sugar content of $12.7{\pm}0.1Brix^{\circ}$. A mixture of the extract, Korean herbal powder, and wheat flour was prepared as the fish cutlet batter. The fish cutlet prepared with the batter had a hardness of $166-202g/cm^2$ and Hunter's color scale values L of $31.14{\pm}2.1$ to $34.62{\pm}1.3$, a of $-4.89{\pm}0.21$ to $-2.26{\pm}0.19$ and b of $-20.65{\pm}2.65$ to $28.93{\pm}3.14$. The FRAP (ferric reducing antioxidant power) and VBN (volatile basic nitrogen) of the fish cutlets were measured to evaluate functionality and determine the optimal mixing ratio for cold storage at $-12^{\circ}C$, $-18^{\circ}C$, and $-24^{\circ}C$. The optimum mixture ratio of extracts /Korean herbal powder/ wheat flour was 1:6:3.

• Horticultural Science & Technology
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• v.34 no.6
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• pp.959-965
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• 2016

In 1994, a new cultivar 'Joyskin' was created from a cross between the cultivars 'Whangkeumbae' and 'Waseaka' at the Pear Research Institute of the National Institute of Horticultural and Herbal Science, Rural Development Administration. In 2006, the 'Joyskin' was selected from among the 317 seedlings resulting from the cross for its skin and taste qualities. Regional adaptation tests were conducted in nine regions and in ten experimental plots from 2006 to 2011. The cultivar was named in 2011. 'Joyskin' showed a vigorous growth habit and semi-spread characteristics similar to 'Whangkeumbae'. The average full bloom date for 'Joyskin' was April 21st, which was also similar to 'Whangkeumbae'. The optimum fruit ripening time was September 6-8th, which was six or eight days earlier than 'Whangkeumbae'. The fruit was round in shape and the skin was a golden yellow color at maturity. The average fruit weight was 320 g and the flesh firmness was $2.5kg/8mm{\varphi}$. The firmness of the fruit skin determined by a blade-type plunger of texture analyzer was 22.9 N, which was significantly different from that of 'Whangkeumbae' 29.9N. Stone cell analysis of 'Joyskin' by phloroglucinol-HCl, showed that 'Joyskin' stone cells were small in size and few in numbers cpmpared to those of cultivars of was 'Manpungbae', 'Niitaka', and 'Whangkeumbae'. The patent application for 'Joyskin' was submitted in April, 2012 (Grant No. 2012-337). In 2016, 'Joyskin' (Grant No. 5895) was registered as a separate record, with uniformity and stability per Korean Seed Industry Law.

• Korean Journal of Agricultural Science
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• v.16 no.2
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• pp.225-238
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• 1989

These studies were conducted to investigate the extraction, purification and characterization of oriental pear (Niitaka. Pyrus pyrifolia Nak.) protease, and the results obtained were as follows: 1. Oriental pear protease was effectively extracted by the method of homogenizing pear pulp with 0.7 volume of 0.1M-sodium phosphate buffer, pH 6.5 containing 5mM-cysteine, 40mM-2-mercaptoethanol and 2mM-EDTA at 10,000 rpm for 5 min. 2. The protease was purified by ammonium sulfate fractionation, Sephadex G-100 filtration and DEAE-Sephadex A-50 column chromatography, and the purified enzyme gave a single protein band on polyacrylamide gel electrophoresis. 3. The specific activity of purified enzyme was 29.65 unit/mg protein and the yield was 7.22%. 4. The moecular weight of the protease was estimated to be about 51,000 by SDS-polyacrylamide gel electrophoresis, and the enzyme had Km value of 54.5 mg/ml for casein. 5. The purified enzyme had a maximum activity at pH 6.0 and $50^{\circ}C$, and was stable from pH 5.5-6.5 and at temperatures below $50^{\circ}C$ 6. Casein was a better substrate for this protease compared to hemoglobin. 7. The enzyme activity was markedly inhibited by p-chloromercuribenzoic acid and heavy metal salts such as $HgCl_2$ and $MnSO_4$ also considerably inhibited the enzyme activity.

• Journal of Plant Biotechnology
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• v.42 no.1
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• pp.25-33
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• 2015

A PyrcpPR-10 gene with differentially expressed was isolated by using the suppression subtractive hybridization assay between '93-3-98' (highly resistant against scab caused by Venturia nashicola) and 'Sweat Skin'(highly susceptible) and analyzed the expression pattern according to organs and cultivars. The full length of PyrcpPR-10 was cloned as 743bp with 480bp's ORP, and was determined to encode a protein of 159 amino acid residues. On analyzing PyrcpPR-10 gene sequence compared with resistant and susceptible cultivars, 'Hwangsilri' (resistant), 'Gamcheonbae' (moderately resistant), 'Wonhwang' (moderately susceptible), 'Niitaka' (highly susceptible), and 'Sweat Skin' (highly susceptible) had identical gene sequence but 'Bartlett' (highly resistant) showed partly different sequences. The deduced amino acid sequence showed 64 ~ 98% homology and had the GXGGXG motif to known amino acid of other plants PR-10 by the BLAST X analysis. Among several organs or tissues, petal was showed highest expression level of PyrcpPR-10 gene followed by leaf, floral axis, bud, and bark. The expression level of PyrcpPR-10 gene was dramatically increased at 24 hr after inoculation in all cultivars and also up-regulated in accordance with resistant degree of cultivars. While resistant cultivars ('Bartlett', '93-3-98', and 'Hwangsilri') induced relatively high expression level of PyrcpPR-10 gene, susceptible cultivars ('Niitaka', and 'Sweat Skin') showed low expression level. PyrcpPR-10 gene is assumed that it is directly connected with defense mechanisms to pear scab.