• 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.

• Journal of Biosystems Engineering
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• v.35 no.5
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• pp.316-322
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• 2010

The packaging of fruits is very important because appropriate packaging can optimize the maintenance of freshness of fruits during their distribution in low or normal temperatures until the products reach consumers. The focus of this study was on the use of functional packaging materials for the post-harvest maintenance of the freshness of fruits. Oak charcoal has excellent far infrared emission and ethylene absorption qualities, and we developed a charcoal-processing packaging linerboard to evaluate the possibility for the use of charcoal as a functional packaging material for pears. Oriental pears of the Niitaka cultivar used in this study account for about 70% of pears harvested every year, and are a very popular domestic fruit in Korea. Pears packaged in packaging materials processed with charcoal were of significantly higher quality (p<0.05) than those packaged with conventional packaging materials, suggesting that charcoal-processed packaging materials can be used as functional packaging material for extending the storability and distribution time of fruits. Charcoal-coated linerboard was shown to be the most appropriate packaging material based on its compression strength, ethylene absorption performance, and the firmness and minimal weight loss of pears.

• 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.

• Korean Journal of Plant Resources
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• v.36 no.1
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• pp.100-106
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• 2023

In order to control the fire blight disease, all plants within the radius of the diseased orchard were removed in the early stage of the outbreak, or antibiotics control was performed for prevention. Since the beginning of antibiotics use on plants, the potential for development of resistance to antibiotics by the plant pathogen and unintended detrimental effects on the fruit trees and environment has become a problem. The purpose of this study is to determine the degree of phytotoxicity to fruit trees caused by excessive spraying of the fire blight disease disinfectant and to establish basic data for safe disinfectant guide. We analyzed whether damage to the fruit tree and the maximum residual limit of fruit was exceeded when three kinds of the fire blight disease disinfectants were continuously sprayed in excess of the number of safe use during the growing season. There was no phytotoxicity in apple 'Fuji' and pear 'Niitaka', and oxolinic acid was detected beyond the limit of quantitation in 'Fuji' grown without a bag, and the other disinfectants were detected below the maximum residue limit. When these disinfectants are continuously sprayed in excess of the number of safe, phytotoxicity may remain on the fruit. Therefore, it is necessary to observe the prescribed dilution factor and observe the safe frequency and the timing of use.

• Korean Journal of Organic Agriculture
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• v.24 no.3
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• pp.557-570
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• 2016

Growth of 6-year old 'Niitaka' pear (Pyrus pyrifolia Nakai) trees and control of insect and disease occurrences were compared between fermented soybean extracts and rain-shelter system for two years. Foliar application of fermented soybean extracts was applied at 6 times as a pre-experiment in the open-field in 2013, with a rain-shelter system in 2014. Fermented soybean extract treatment increased foliar concentrations of approximately 0.46% T-N, 0.17% K, 0.19% Ca, and 0.06% Mg in 2013 compared to the control, with similar macro-nutrients between the control and soybean extract treatment observed in 2014. Rain-shelter system increased foliar concentrations of T-N, Ca, and Mg compared to the open-field. There were no significantly different between the control and soybean extract treatment for number of leaves per fruit, leaf dry weight, phytotoxicity, and completed shoot growth on August during the two years. Rain-shelter system increased leaf dry weight and did not affect phytotoxicity in the leaves. Fruit quality parameters were mostly similar to control and soybean extract treatment for two years, with higher fruit firmness observed for soybean extract treatment. Rain-shelter system advanced 4 days of harvest dates, and increased approximately 7.0 ton fruit yield per ha, 20 g mean fruit weight, and fruit soluble solid contents compared to open-field in 2014. Soybean extract treatment little suppressed occurrence of disease and insect on the leaves and fruits in both years. Rain-shelter system increased occurrence of Venturia nashicola on the leaves and to 63.8% of Gymnosporangium asiaticum on the fruits in 2014. Strong winds and storms in May elevated relative humidity in the rain-shelter system and caused high infection of the disease occurrence, requiring for an additional green control method. Soybean extract treatment little affected tree growth and would have initiated for a long-term study to evaluate tree physiological characteristics. Rain-shelter system improved fruit productivity and advanced harvest dates, which could have been more effective facility at a Thanks Giving Day between middle and end of September.

• Korean Journal of Agricultural and Forest Meteorology
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• v.22 no.4
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• pp.268-278
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• 2020

Flowering time has been put forward due to the recent abnormally warm winter, which often caused damages of flower buds by late frosts persistently. In the present study, cumulative chill unit and cumulative heat unit of Niitaka pear, which are required for releasing the endogenous dormancy and for flowering after breaking dormancy, respectively, were compared between flowering time prediction models used in South K orea. Observation weather data were collected at eight locations for the recent three years from 2018-2020. The dates of full bloom were also collected to determine the confidence level of models including DVR, mDVR and CD models. It was found that mDVR model tended to have smaller values (8.4%) of the coefficient of variation (cv) of chill units than any other models. The CD model tended to have a low value of cv (17.5%) for calculation of heat unit required to reach flowering after breaking dormancy. The mDVR model had the most accurate prediction of full bloom during the study period compared with the other models. The DVR model usually had poor skills in prediction of full bloom dates. In particular, the error of the DVR model was large especially in southern coastal areas (e.g., Ulju and Sacheon) where the temperature was warm. Our results indicated that the mDVR model had relatively consistent accuracy in prediction of full bloom dates over region and years of interest. When observation data for full bloom date are compiled for an extended period, the full bloom date can be predicted with greater accuracy improving the mDVR model further.

• 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.

• Food Science and Preservation
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• v.16 no.3
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• pp.305-310
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• 2009

This study was conducted using 8-year-old 'Niitaka' (Pyrus pyriforia) pear trees to investigate the effect of different organic fertilizers on fruit quality and level of total phenolicsin a conventionally managed orchard. Trees were treated with one of five different fertilizers: 1) control (60 g of chemical fertilizer [16N-11P-12K] per tree) 2) rice bran (RB, 10 kg per tree); 3) coffee bran compost (CBC, 10 kg per tree); 4) chitin-incubated compost (CIC, 10 kg per tree); or 5) RCC (RB+CBC+CIC, 30 kg per tree). Soluble solid content, hardness, and titratable acidity were significantly higher in fruit from RCC-treated trees compared with fruit from trees exposed to other treatments. Overall, control fruit had smaller stones and lower calcium concentration than had organically fertilized fruit. Also, control fruit showed a reduced level of total phenolic compounds and lower antioxidant activity in both peel and flesh than did organically fertilized fruit. Compost-treated trees yielded fruit of enhanced edibility and with longer shelf-life owing to a reduction in stone size and increased calcium concentration, respectively. Overall, fruit from trees treated with organic fertilizers was of higher quality and had greater antioxidant levels compared with fruit from trees treated with chemical fertilizer.

• Korean Journal of Organic Agriculture
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• v.19 no.2
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• pp.229-243
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• 2011

Consumers' interest and government's support for the fruits rapidly increased organic fruit productions. This study was examined to compare the soil physicochemical and microbial properties of orchards soil in conventionally and organically management systems. Organic cultivation had lower soil bulk density, solid phase, and penetration resistance than the conventional cultivation. Soil pH and organic matter contents increased from March to August, and the values were greater in the organic cultivation than the conventional cultivation. Total nitrogen (N) and phosphorous concentrations decreased from March to August, and the organic soils had greater N but lower phosphorous concentrations than the conventional soils. Soil microbial carbon biomass increased 36% and 15% for organic and conventional cultivations, respectively, from March to August. Soil microbial N biomass was greater in June than March or August, and the organic cultivation had a greater biomass N compared to the conventional cultivation. Soil dehydrogenase and chitinase activities were greater in June than in March or August. ${\beta}$-glucosidase activity declined in both cultivations, while the phosphatase activity increased. Organic cultivation had greater enzyme activities in March, June, and August, except for the acid phosphatase activity in June.

• Korean Journal of Organic Agriculture
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• v.25 no.1
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• pp.85-99
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• 2017

The study was compared for ability to supply macro-nutrients between time and height of mowing to establish alternate technique of a chemical fertilizer with 9-year old 'Niitaka' pear (Pyrus pyrifolia Nakai) trees in a pesticide-free orchard in 2009. Rye and hairy vetch were sown together during fall 2008. Four types of mowing time treatments were included; mowing on April 18+May 28, on April 28+June 8, on May 8+June 18, and on April 18+May 18+June 18. Mowing height treatment included mowing at $3{\pm}1cm$, $7{\pm}1cm$, and $13{\pm}1cm$ on April 18 or June 8. Mowing on May 8+June 18 increased the most dry weight of ground cover and vegetation to 14,480 kg per ha among the mowing time treatments, resulting in the greatest production of T-N (total nitrogen; 292 kg) and K (396 kg) per ha on the soil. Mowing at $7{\pm}1cm$ decreased the most dry weight of ground cover and vegetation to 11,970 kg per ha among the mowing height treatments, resulting in the lowest production of T-N (265 kg), P (111 kg) and K (333 kg) per ha in a soil. Ground cover treatments increased soil organic matter contents, regardless of mowing treatment methods.