• Horticultural Science & Technology
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• v.19 no.1
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• pp.60-65
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• 2001

'Shinil' pear cultivar (Pyrus pyrifolia Nakai) which was originated in a cross between 'Shinko' (non-patented, released in 1941) and 'Hosui' (non-patented, released in 1972) in 1978 was released as a middle season harvest variety. Its usual picking time coincided with 'Chuseok' season which is one of the most famous national holiday in Korea. The fruit showed high soluble solids content and good appearance. The cultivar was preliminarily selected in 1991, and its regional adaptability was evaluated in the name of 'Wonkyo Na-13' at 9 sites for four years from 1992, and finally selected and named in 1995. 'Shinil' is medium in tree vigor like 'Hosui' and spreading in tree habit as 'Niitaka', a leading cultivar in Korea, and consistently very productive. It has high resistance to black rot caused by Alternaria kikuchiana and pear necrotic spot caused by pear necrotic spot virus. Its full bloom is one day earlier than that of 'Niitaka' cultivar and harvest time is September 25 at Suwon area which is 3 days later than that of 'Hosui'. Fruit is round in shape with a deep medium stalk cavity and medium calyx basin and has attractive light yellow brown skin color. The fruit weight ranges between 300 and 400 g, which is similar to 'Chojuro', 'Shinko', and 'Hosui'. Soluble solid content is approximately at the level of 13-14 Brix, which is higher than that of 'Chojuro'. The flesh is cream-white, very juicy, and light grit with soft and fine texture.

• Korean Journal of Environmental Agriculture
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• v.35 no.3
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• pp.175-183
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• 2016

BACKGROUND: There's a long rainy season during the Summer in Northeast Asia, including Korea. Heavy rainfall during this season causes harm to tree's root, and damped injury in the pear has been continuously reported. Pear Research Institute is breeding damp resistant rootstocks and investigating their mechanisms to relieve damped damages in the pear.METHODS AND RESULTS: Seedlings of Pyrus betulaefolia and P. calleryana were divided into two groups: control and damped, respectively. Damped group was treated by constant irrigation for 77 days and control group was maintained to keep the soil moisture pressure between 0 and -10 kPa. After the treatment, we analysed trees' growth rate, chlorophyll content, amino acids and total phenolic compounds. As a result, P. betulaefolia was sensitive to damped treatment while P. calleryana did not have significant differences between the control and damped treatment. It was observed that total contents for phenolic compounds were dramatically increased in P. betulaefolia while trees' growth rate, chlorophyll b and general amino acid contents were lowered by damping treatment.CONCLUSION: In some pear cultivars, growth habit is suppressed by damped damage. Pyrus calleryana displayed tolerances to damped damage in growth rate and some organic compound contents compared to P. betulaefolia. So we recommend to exploit P. calleryana as a pear rootstock rather than using P. betulaefolia.

• Journal of the Korean Society of Clothing and Textiles
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• v.38 no.2
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• pp.201-215
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• 2014

This study explores the kinds and types of dyes used in the Joseon Dynasty. Some literature including "Sanga Yorok", "Gyuhap Chongseo", "Imwon Gyeonjeji" were reviewed for this purpose. The findings are as follows. The colors obtained from the dyes were divided into seven color series, such as red, yellow and orange, green, blue, purple, brown, gray and black. These are practical color categories differed from abstract five cardinal colors [五方色]. The diachronic dyes used during the Joseon Dynasty were safflower and Japanese alder bark for red, indigo leaves for blue, gromwell for purple, chestnut tree bark for brown. The representative dyes used in the late Joseon Dynasty were safflower and sappan wood for red, wild pear tree bark and Pentapetes phoenicea for yellow and orange, indigo leaves for blue, sappan wood and gromwell for purple, mulberry tree for brown, and Chinese ink for gray. Common dyes used both in Joseon and China were safflower and sappan wood for red, pagoda tree blossom for yellow, a combination of pagoda tree blossom (or Amur cork tree) and indigo leaves (or sediment) for green, indigo leavers or sediment for blue, sappan wood and hollyhock for purple, and a combination of indigo leaves and Galla Rhois for gray and black.

• Korean Journal of Medicinal Crop Science
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• v.15 no.5
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• pp.335-338
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• 2007

Five samples (Bakwoonbae, Chungsilbae, Sandolbae, Dolbae, and Chuwhangbae) of Pyrus species differing in their origin of production were analyzed for total phenolic content, vitamin C content, and antioxidant activities. Two antioxidant activities were measured by the free-radical scavenging activity and reducing power method. Total phenolic content of the Chungsilbae extract (20.35 mg/g) was higher than those of other pears. Vitamin C content in five Pyrus species ranged from $420.32\;{\mu}g/g$ in Sandolbae to $659.75\;{\mu}g/g$ in Bakwoonbae. Chungsilbae also had the highest free radical scavenging activity (76.56%) and reducing power (0.35).

• Food Science and Preservation
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• v.17 no.4
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• pp.466-470
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• 2010

We investigated the effects of organic mulches on the tree and fruit qualities of "Niitaka" (Pyrus pyriforia) pear trees. Trees grown with rice straw mulch had significantly greater potassium (K), magnesium (Mg), and calcium (Ca) concentrations in leaves compared with control trees and those mulched using bark or polyethylene, but the concentrations were below the recommended levels for these nutrients in pear leaves. Bark mulch increased fruit firmness and soluble solid (SS) levels, compared with rice straw mulch. The fruit of trees grown with bark mulch had a higher ratio of SS to total acidity in fresh fruit, and the fruit was dark red in color. The K and Ca concentrations were highest in fruit grown on trees mulched with rice straw and bark, respectively, and competition between the levels of these cations was evident in fresh fruit. Bark and rice straw mulches increased overall fruit quality, and reduced fruit stone size, whereas a polyethylene mulch, devoid of organic material, resulted in a fruit stone size similar to that of the control.

• Korean journal of applied entomology
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• v.14 no.4 s.25
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• pp.215-219
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• 1975

The number of instars of pear sawfly larvae (Janus piri Okamoto) collected front field pear trees, were determined by measuring the width of head capsule, and the growth ratio in each instar was also studied. 1. The larval head width had six distinct peaks, which suggests that the larva of this insect passes six instars. 2. The head width tended to increase as the instars avdance, except in tile first and second instars. The coeffieient of variation decressed as the instars advanced. The growth ratio, which was similarly great in the first and second instars, decreased as the instars advanced. 3. Gains' and Campbell's formulae seemed to be more suitable than Dyer's for the determination of larval instars of this insect by the measurement of headwidth. 4. The larval instars could be inferred from the extent of damage to pear tree by this insect; that is the larvae in the second to fourth instars usually gave slight and invissible damage, while those in the fifth to sixth instars gave rapid and severe damage.

• 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 Environmental Biology
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• v.42 no.3
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• pp.232-240
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• 2024

Due to rapid spread of fireblight, the Rural Development Administration is supplying bactericides to farmers. However, research on inhibitory effects of main active ingredients in these bactericides on fireblight is lacking. Chlorophyll fluorescence analysis is a non-destructive method for analyzing the photosynthetic efficiency of plants, enabling time-series data analysis of pathogen progression and allowing for large-scale studies. Therefore, this study analyzed inhibitory effects of main active ingredients in bactericides on fireblight using chlorophyll fluorescence response analysis. Flowering pear trees (three-year-old 'Shingo' variety) were sprayed with control agents and fire blight pathogens on flowers. Chlorophyll fluorescence responses were then measured at seven-day intervals. Twenty-eight days after bactericide treatment, the fluorescence of the O-J transition stage in the untreated group was twice as high as in the average bactericide-treated group presumably due to inhibition of electron transport in the PSII donor side caused by pathogen infection, leading to leaf necrosis. Additionally, the electron transport efficiency (ET2o, RE1o) decreased, reducing the driving force of photosynthesis (DF total ABS) to 20% of the average bactericide-treated group, indicating chlorophyll damage and reduced photosynthetic capacity. In conclusion, chlorophyll fluorescence technology can be used to quantitatively evaluate the efficacy of fire blight control agents during the flowering period of pear trees.

• 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

• Korean Journal of Agricultural and Forest Meteorology
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• v.9 no.4
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• pp.228-233
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• 2007

Pear psylla, Caccopsylla pyricola (Homoptera: Psyllidae), is a serious insect pest in pear orchards. C. pyricola overwinters as adults under rough bark scales of pear trees. When the weather warms up in the spring, the overwintered adults become active, climb up to the tree branches, and inhabit on fruit twigs to lay eggs. This study was conducted to develop a forecasting model for the onset of upward-movement of overwintered C. pyricola adults to control them by timely spraying of petroleum oil. The adult population densities were observed under rough barks (B) and on fruit twigs (T) of pear trees. Relative upward-movement rates (R) were calculated as T/(B+T). Low threshold temperatures for the activation of overwintered C. pyricola adults were selected arbitrarily from 5 to $9^{\circ}C$ at a $1^{\circ}C$ interval. Then, the days (D) when daily maximum air temperatures were above each low threshold temperature were counted from 1 February until to the dates with R $\geq$ 0.8. The same methods were applied for the prediction of the first observation of eggs. The variation of coefficients (CV) for the mean Des were lowest with the low threshold temperature of $6^{\circ}C$. At this selected threshold temperature, the upward movement of C. pyricola adults occurred with 12 D and they started laying eggs with 25 D. In the field validation, the model outputs with the $6^{\circ}C$ threshold temperature reasonably well explained the observed data in Suwon and Cheonan in 2002. Practical usages of the model were also discussed.