• Korean journal of applied entomology
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• v.41 no.3
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• pp.199-204
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• 2002

Population fluctuation of O. kashmirica benefica, a major natural enemy of citrus red mite (Panonychus citri), was surveyed from 1997 to 2000 in yuzu orchards in Goheung region and, developmental periods, developmental threshold temperature (DT) and effective cumulative temperature (ET) were estimated. Under four constant temperatures of 15, 20, 25 and 30$\^{C}$, developmental periods from egg to adult of the beetles were 67.3, 31.4, 19.4 and 15.3 days, respectively. The period of each stage was long in the order of pupa> egg > 3rd larva> 2nd larva> 1st larva. Mean numbers of eggs oviposited by a female per day were 3.3, 5.6, 7.3 and 7.7 under the temperatures, respectively. The highest hatchability (92%) and adult emergence (60%) were shown under 25$\^{C}$. Adult longevity was 54.3 days for females, and 58.6 days for males. In natural condition, the sex ratio of the beetle was 0.58. Developmental thresholds (DT) for egg, 1st, 2nd, 3rd larva, pupa, and egg to adult were 12.7, 10.0, 10.8, 7.9, 10.1 and 10.6$\^{C}$, respectively. The effective cumulative temperatures (ET) were 41.4, 22.9, 22.7, 46.6, 165.3, 292.9 day-degree at the same development stage, respectively. The beetle occurred from early April to early December in yuzu orchards. The population peak of the beetles was dependent on the amount of prey mite (Panonychus citri), and the ratio of the predator to prey mite was 1 to 100-200 at predator peak stage in the field.

• Food Industry And Nutrition
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• v.19 no.2
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• pp.28-34
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• 2014

• Proceedings of the Korean Society of Plant Pathology Conference
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• 1999.10a
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• pp.55.1-55
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• 1999

• Proceedings of the Korean Society of Plant Pathology Conference
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• 1999.10a
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• pp.55.2-55
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• 1999

• Journal of Plant Biotechnology
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• v.29 no.3
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• pp.185-188
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• 2002

Off-white, friable embryogenic calluses were formed on the internal integument of mature seeds of yuzu (Citrus junos) cultured on Murashige and Skoog's basal medium at a frequency of 1.2%. Embryogenic calluses were proliferated when cultured on medium with 1 mg/L 2,4-D. Upon transfer to medium with 0.1 mg/L kinetin, embryogenic calluses produced numerous somatic embryos. Embryogenic suspension cultures were established by placing embryogenic calluses into liquid medium with 1 mg/L 2,4-D. When plated onto medium with 0.5 mg/L ABA, embryogenic cells developed into somatic embryos at a high frequency, and then regenerated into plantlets. Plantlets were successfully transplanted to potting soil and grown in a greenhouse.

• The Plant Pathology Journal
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• v.19 no.5
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• pp.248-252
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• 2003

This study was carried out to evaluate potential of Shiranuhi cultivar against inoculation of causal pathogen of citrus canker, Xanthomonas axonopodis pv. citri in Jeju Island by comparing degree of susceptibility of fruits and leaves/twigs, and analysis of incidence of canker disease. Progression of symptom, disease incidence, and percent area of lesion were surveyed for evaluation of resistance. In greenhouse condition, symptoms of bacterial citrus canker progressed more rapidly in sweet orange, a moderately susceptible cultivar, than in other four cultivars (satsuma mandarin, 'Kiyomi', 'Shiranuhi' and 'Yuzu'). At 20 days after inoculation, disease severity was the highest in sweet orange (5.0$\pm$0.0), and all tested leaves were distorted or had dropped. On the other hand, 'Yuzu' showed the lowest disease severity (2.6$\pm$0.47), followed by 'Kiyomi' (4.0$\pm$0.0), 'Shiranuhi' (4.0$\pm$0.82), and satsuma mandarin (4.3$\pm$0.47). Percent area of lesion per leaf 30 days after inoculation was the highest in sweet orange (8.31$\pm$1.78), followed by satsuma mandarin (1.51$\pm$1.25), 'Shiranuhi' (1.39$\pm$0.94), and 'Kiyomi' (1.1$\pm$0.9), while the lowest was in 'Yuzu' (0.26$\pm$0.17). Infield condition, percentage of diseased leaf in 'Shiranuhi' was very low, 5.2$\pm$2.9, compared with sweet orange, 71.0$\pm$ 11.5, while that of satsuma mandarin and 'Kiyomi' were 6.9$\pm$7.0 and 4.3$\pm$2.0, respectively. Percentages of diseased leaf was higher (17.4$\pm$7.1) than that of diseased fruit (3.2$\pm$2.5) in severely diseased trees of Shiranuhi cultivar, and the disease was not observed on twig in open field condition. Lesion sizes on leaves and fruits in open field condition were 4.1$\pm$2.2 mm2 and 5.1$\pm$5.6 mm2, respectively, while those in greenhouse condition were 8.7$\pm$5.7 mm2, 10.4$\pm$9.2 mm2 and 5.6$\pm$2.6 mm2 on leaves, fruits and twigs, respectively. The disease was observed in 5.6% out of total 107 farmers Shiranuhi fields under polyethylene film house, and average percentages of diseased tree in 31 fields of Shiranuhi cultivar and adjacent satsuma mandarin fields were 0.02% and 14.8%, respectively. Average percentage of diseased fruit was 1.6% in satsuma mandarin which was not observed in anyone of all the 31 Shiranuhi farmers fields. Therefore, it was concluded that 'Shiranuhi' cultivar is not potential against causal pathogen of citrus canker disease in Jeju Island because the cultivar has similar resistance as satsuma mandarin which occupies over 95% of total 25,000 ha in Jeju Island in polyethylene film houses protected from outside.

• Journal of Plant Biotechnology
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• v.32 no.1
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• pp.45-50
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• 2005

Virus-free stocks was produced by the combination of the heat treatment of virus infected plant and shoot-tip grafting (STS). To produce virus-free stocks, the plants infected with citrus viruses were used for virus-free stock production using the modified method of STG in thermotherapy at $40^{\circ}C$ for 16 hours in the light, and at $30^{\circ}C$ for 8 hours of darkness for 4 weeks. Trifoliate orange (P. trifoliata) were used as rootstock seedling for STG. Percentages of virus-free stocks against citrus tristeza virus (CTV), satsuma dwarf virus (SDV) and citrus tatter leaf virus (CTLV) were $75.7\%,\;100.0,\%\;82.6\%$ respectively. Shoot tip size for successful STG were as small as possible. Less than $0.3\;\cal{mm}$ of shoot tips gave the hight efficiency of virus free plants but survival rates were low. And, survival rate after shoot-tip culture was analyzed and the rates were dependant on the cultivars; Yuzu cultivar showed the hight survival rate ($74.6\%$) and early satsuma mandarin (Iwasagi) was $13.3\%$ as the lowest cultivar. But citrus trees were not succeed to grown, turned brown, and died.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.124-124
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• 2003

Citrus canker is very important disease in international trade of citrus. The disease was usually take place from late of June, and severe middle of July to middle of August, though disease occurrence was affected by environmental conditions. In pathogenicity test, three varieties, orange, lemon and kiyomi among 7 varieties, were succeptible, two varieties, satsuma mandarin and iwasachi, intermediate resistant. On the other hand, shiranuhi and yuzu were resistant relatively. The pathogen, Xanthomonas axonopodis pv. citri, grew well in PD broth adjusted to pH 7.0 at 26$^{\circ}C$. It's growth was best in medium containing group of monosaccharide as a carbon source and group of ammonium as a nitrogen source. Tow isolates were resistant to streptomycin among 11 isolates isolated from diseased leaves in field in Jeju-Do. The streptomycin sensitives isolate was controlled by in greenhouse test. On the other hand, the resistant and sensitive isolates were controlled by treatment with copper sulfate, the control value is 88.7％ and 90.6％, respectively.

• The Korean Journal of Food And Nutrition
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• v.3 no.1
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• pp.69-79
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• 1990

Koryo(918-1352) made a certain progress in her culture and agriculture except the latter part of the era when the development in social economy were retarded due to military dictatorship and Mongol invasion. Despite of these external conditions, cultivations and kinds of horticulture foods were expanded With the help Of many king's agriculture first policy and the advancement in cultivating method . Among the horticulture foods, fruits such as peach, plum, Japanese apricot, apricot, cherry, pear, persimmon, pomegranate, crab apple, Jujube, grape, Chinese quince, walnut, orange, yuzu, chestnut, ginkgo nut(silvernut), pine nut, nutmeg nut, and fiat were crowed, and vegetables such as Chinese cabbage, turnip, radish, garlic, welsh onion, gynmigit, scallion, taro, malva, cucumber, white gourd, bottle gourd, water melon, eggplant, Japanese ginger, ginger and litchi were cultivated, while semi, water shieled and bamboo sprouts were taken in natural. Fruits were taken in natural or through dry, and particularly grapes were used to make wine, Flowers of Japanese apricots, some fruit trees, and chrysanthemum were also made into wine. Certain fruits were used as medicine owing to its medicinal nature. Vegetables were used to make Kimchi or to boil soup, sometimes they were dried to be kept in storage to be used in rare season and also used as medicine Increase in kinds of horticulture foods does not have any direct relation with the reform of social economy, but the fact that so many kinds of horticulture foods were cultivated and used in Koryo era shows that they elevated people's life and dietary culture.

• The Korean Journal of Food And Nutrition
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• v.36 no.4
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• pp.334-339
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• 2023

To suppress mold generation of yujacheong, Penicillium chrysogenum LB31 was cultured, and spores were harvested and put into yujacheong. Antioxidant activity, useful ingredients, mold size and incidence were investigated while storing yujacheong for 30 days, after sterilization with different methods (nontreatment, ozone gas emission, heating after ozone gas emission and heating). The results showed that the content of narirutin, naringin, hesperidin, or neohesperidin, which are functional components of yuzu, increased as the storage period increased in all the treatment units. In addition, mold generation was not observed until the 15th day in the heat treatment group after ozone gas emission. As the treatment group emitted ozone gas. molds of 34.8 and 112 mm2 in size were observed on the 30th day. These results suggested that ozone sterilization can prevent microbial contamination, further extending the shelf life of yuzacheong and maintaining a fresh state.