• Journal of Bio-Environment Control
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• v.11 no.1
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• pp.1-4
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• 2002

The occurrence rate of russet in 'Whangkeumbae' pear showed significant difference by years because the russet occurrence is greatly affected by the amount of rainfall. This study was conducted to analyse the relationship between rainfall and russet occurrence by artificial treatment of high humidity. Under high relative humidity condition, stomatal resistance decreased and average fruit weight was higher since the increased net photosynthesis rate accumulation accelerated fruit growth. The russet occurrence began on July 25, when the growth speed of fruit weight and fruit surface is the most fast. Russet occurrence rate was higher in high relative humidity condition because the fruit growth was accelerated. Since the fruit calcium concentration change is extreme in late July, it is assumed that the deceased calcium content is related to the occurrence of russet in 'Whangkeumbae' pear, When the high relative humidity condition is maintained after rainfall, the amount of net photosynthesis rate increase and fruit growth is accelerated. Therefore, the unbalance in the amounts of transferred photosynthesis assimilation product, water and mineral elements would be one of the reasons for the russet occurrence in 'Whangkeumbae' pear.

• 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%.

• The Plant Pathology Journal
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• v.17 no.6
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• pp.382.3-382
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• 2001

• 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.

• Horticultural Science & Technology
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• v.34 no.4
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• pp.655-661
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• 2016

To develop scab-resistant pear (Pyrus spp.) varieties with fruits that are as crisp and juicy as Asian pears, a cross was made between 'Whangkeumbae' and 'Bartlett' varieties (P. pyrifolia ${\times}$ P. communis) at the Pear Research Institute of the National Institute of Horticultural & Herbal Science, Rural Development Administration, in 1994. Among the 285 seedlings, 'Greensis' was first selected in 2006 for its good eating quality and named in 2012 after regional adaptation tests in nine regions and ten experimental plots from 2007 to 2012. The tree showed a vigorous growth habit and semi-spreading characteristics, like 'Whangkeumbae'. The optimum fruit harvest date was also around Sept. 26 and fruit was round in shape and green in skin color at maturity. Average fruit weight was 470g, and the soluble solids content was $12.4^{\circ}Brix$. The flesh was very crisp and juicy, and had good eating quality. Its' leaf size was similar with 'Bartlett' and smaller than 'Whangkeumbae'. The average of full bloom date of 'Greensis' was determined as Apr. 26, which was six days later than 'Whangkeumbae' and similar with 'Bartlett'. S genotypes of 'Greensis' were identified as $S_4S_e$ by S-allele PCR product sequencing analysis. It seems that the $S_4$ allele was inherited from 'Whangkeumbae' and the Se allele from 'Bartlett'. 'Greensis' displayed strong resistance to scab disease caused by Venturia nashicola, similar to European pear cultivars like 'Beurre Hardy' and, 'Conference'. 'Greensis' was also highly resistant to black leaf spot (Alternaria kikuchiana) in the field

• Journal of agriculture & life science
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• v.43 no.6
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• pp.59-65
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• 2009

Combinations of plant growth regulators, darkness treatments, and the order of expanding leaves for explants were evaluated for optimizing in vitro shoot regeneration rate of 'Whangkeumbae' pear. In a MS medium, supplemented with $8.88{\mu}M$ 6-benzylaminopurine (BA) and $0.49{\mu}M$ indole-3-butyric acid (IBA), green foci were observed on the surface of the callus 8 days after culture initiation. Some adventitious buds were later induced from those green foci, resulting in the appearance of normal shoots. In a medium containing $22.20{\mu}M\;BA$, the surface of the callus became compact and greenish, and many adventitious buds were formed over the entire area of the callus surface. When comparing BA concentration via histological observation, the section which had been treated with $22.20{\mu}M\;BA$ exhibited closer cell aggregation than those with $8.88{\mu}M\;BA$. The darkness treatment enhanced the formation of adventitious shoots for up to 3 weeks. The youngest two expanding leaves, proximal to the shoot apex, were proved to be the most regenerative, and yielded the highest shoot number per regenerating leaf. A fourth strength MS medium, which was supplemented with $0.54{\mu}M\;NAA$, yielded good quality plantlets, with regard to root number and root length.

• Korean Journal of Environmental Agriculture
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• v.26 no.2
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• pp.171-178
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• 2007

Diffusion and accumulation of ethoprophos in fruit such as apple and two types of pears were examined by dipping them into the solution of ethoprophos. The effective diffusivities of ethoprophos at the skin and flesh of apple and pear were determined by simulation their experimental accumulation curves with calculated ones from the model assuming consecutive diffusion of ethoprophos from skin to flesh. Its effective diffusivity at the flesh with higher content of water were higher, $\sim10^{-10}\;m^2/s$, regardless of the types of fruits, while that at the skin was small, $\sim10^{-12}\;m^2/s$ and increased with the order of 'Niitaka' pear < 'Whangkeumbae' pear < 'Fuji' apple. The variation in the concentration of ethoprophos in its solution did not induce any change in affecting its effective diffusivity at the flesh of 'Whangkeumbae' pear, but the increase in the concentration caused the increase in its effective diffusivity at the skin. The penetration rate of ethoprophos at the skin was an important factor in determining its accumulation rate in fruit.

• Journal of Plant Biotechnology
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• v.39 no.4
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• pp.288-294
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• 2012

In order to establish an efficient adventitious shoot regeneration conditions from leaf explants for Asian pear 'Whangkeumbae', the effect of concentration and kinds of plant growth regulator and carbon source was investigated. Leaf explants of cultures grown on Murashige and Skoog (MS) medium containing 8 g/L plant agar were used. When the medium contained 0.25 mg/L thidiazuron (TDZ) and 0.3 mg/L indolebutyric acid (IBA), the adventitious shoot regeneration rate (ASRR) was greater as 61.1% than others treated and higher TDZ concentrations (2.5 and 5 mg/L) treatment significantly reduced the ASRR. As the effect of IBA and indoleacetic acid (IAA) concentration on the ASRR, 0.5 mg/L TDZ plus different concentration of IAA exhibited relatively high ASRR and 0.5 mg/L TDZ plus 0.3 mg/L IAA showed the highest ASRR of 76.7%. Also the effect of sucrose and sorbitol as carbon source on regeneration was examined. The highest ASRR and the most shoots per explants averaged 94.4% and 3.49 by treatment of 30 mg/L sorbitol, respectably. Sorbitol is considered better carbon source than sucrose for shoot regeneration of 'Whangkeumbae' pear.

• Horticultural Science & Technology
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• v.19 no.1
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• pp.43-47
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• 2001

This study was conducted to investigate the integrated control strategy against pear black leaf spot disease. Using indicator plant PS-95 we selected six virus-free trees (cv. Niitaka) from commercial orchards in the major pear production area. Disease symptom by pear black leaf spot in the shoot of pear (Niitaka) has been successfully inhibited by heat treatments for 3 weeks at temperature of $40^{\circ}C$ (day) and $32^{\circ}C$ (night) or 4 weeks at $37^{\circ}C$ and $30^{\circ}C$, respectively. However, survival rate of the shoot tips on stocks was low. Seven cultivars Niitaka, Imamura- aki, Waseaka, Nijisseiki, Wasenijisseiki, Shinsetsu and Whangkeumbae produced visible symptoms in the first year after inoculation with the virus. Other 11 selections remained symptomless. Two resistant cultivars Suwhangbae and Gamcheonbae were selected, which showed high fruit quality. It is recommended that these cultivars could be top-grafted onto the infected Niitaka trees to overcome the damage caused by the disease in the orchard.

• Horticultural Science & Technology
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• v.18 no.1
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• pp.22-27
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• 2000

National plant quarantine inspector of exporting country should inspect agricultural products according to the quarantine requisites of counterpart country when the commodities are shipped. Export of pear fruits was held because quarantine pests including Conogethes punctiferalis were found at the point of entry in Canada. In order to examine the problems in detail, the inspected pear fruits were stored at a low temperature for 43 days, almost the same period necessary for fruit sorting, quarantine procedures, and transportation by ship. Dead larvae of fruit moths, C. punctiferalis and Grapholita molesta were found during cold storage. Quarantine pathogens were not found, but non-quarantine ones such as Penicillium sp. was infected through wounds by bruises and stabs resulted from sorting procedures. Because of the wounding problem during export procedures, pear fruits with thin exocarp, such as fruits of P. pyrifolia Nakai cv. Whangkeumbae, are required more careful handling during fruit sorting and conveyance.