• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.2
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• pp.207-214
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• 1996

This study was conducted to obtain fundamental information on forage sorghum breeding in forage crop field of Livestock Experiment Station at Suwon from 1986 to 1991. The charcterization of sorghum germplasm was performed through 1986 to 1987, and after parental lines were selected from diverse sorghum germplasm on the basis of flowering date, plant height and several morphological characters for forage sorghum Fl hybrids. The range of variation of 50% flowering date and plant height were greater in order of forage sorghum sudangrass and male sterile line of grain sorghum. The average flowering date was earlier in sudangrass and male sterile line of grain sorghum than forage sorghum lines from the tested sorghum germplasms. And the average plant height was tall in order of forage sorghum, sudangrass and male sterile lines of grain sorghum. There were remarkable morphological variations between sudangrass lines and male sterile lines of grain sorghum such as plant color, leaf midrib color, glume color, seed coat color, head compactness and shape, awns, grain covering and 100 seed weight.

• Current Research on Agriculture and Life Sciences
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• v.3
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• pp.158-165
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• 1985

The study was conducted to obtain some genetic information for breeding of mice. Average performance, heterosis and genetic variance were estimated with 362 progenies from a full diallel cross of four lines of mice (BALB/c, CBA, C3H and C57BL). The progenies were reared at the Experimental Animal Farm. College of Agriculture, Kyungpook National University from November, 1984 to February, 1985. Data for litter size. sex ratio, body weight and weaning rate were analyzed into heterosis effects, and genetic variance with Hayman's model. The results obtained are summarized as follows : 1. Average performance was 7.54 in litter size, 53.20 % in sex ratio, 1.55 g in birth weight, 10.45 g in weaning weight and 94.13 % in weaning rate. 2. The estimated heterois was 6.97% in litter size, 7.26 % in sex ratio, 6.08% in birth weight, 3.54% in weaning weight and 2.05% in weaning rate, respectively. 3. Additive gene effects were not observed in litter size, sex ratio, birth weight, weaning weight and weaning rate. In litter size and weaning weight, dominance effects were observed, which were shown due to individual crosses in litter size and were shown mean dominance effects of parental line in weaning weight. Mat-Maternal effects appeared in birth weight and weaning weight, and reciprocal effects were observed in weaning weight.

• Korean Journal of Agricultural Science
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• v.29 no.2
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• pp.43-52
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• 2002

This study was performed to provide the basic data for preservation and improvement of genetic resources according to finding genetic construction obtained from analysis of genetic characteristics of $\beta$-casein gene in Korean Native goat and Saanen using the PCR-RFLP. This study confirmed the amplified products of 481bp fragments obtained from the amplification of $\beta$-casein loci by PCR. The $\beta$-casein AB genotype showed 481, 284 and 197bp, and $\beta$-casein BB genotype showed 284 and 197bp fragments in Korean Native goat and Saanen. The frequencies of $\beta$-casein genotype in Korean Native goat were 6.25 and 93.75% for AA and AB and the frequencies of $\beta$-casein genotype in Saanen were 57.14 and 42.86% for AA and AB types. The frequencies of $\beta$-casein A and B alleles were 0.031 and 0.969 in Korean Native goat and the frequencies of $\beta$-casein A and B alleles are 0.286 and 0.714 in Saanen, respectively. The nucleotide sequence of $\beta$-casein gene of Korean Native goat was 97.71% higher homology with 11 nucleotide sequences difference of that of goat reported in GeneBank (M90556). Therefore, this study of molecular genetic characteristics by the analysis of genetic polymorphism and sequencing for $\beta$-casein gene should be used as basic and applying data for preservation and improvement of genetic resources in Korean Native goat breeding.

• Research in Plant Disease
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• v.22 no.4
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• pp.264-268
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• 2016

The nursery test against rice blast in Korea from 2014 to 2015 was analyzed. The average of disease severity of leaf blast in 12 sites showed $3.7{\pm}2.1$ in 2014 and $4.4{\pm}2.1$ in 2015. Disease severity of leaf blast in Icheon and Cheolwon was increased ranging from $2.8{\pm}2.2$ in 2014 to $6.3{\pm}1.8$ in 2015. Using a designation system, a total of 588 isolates collected those years were categorized into 34 races in 2014 and 51 races in 2015 based on the reaction pattern of Korean differential varieties. The blast isolates of 2015 were more diverse than those in 2014. The ratios of KI race to KJ race were 54:46 in 2014 and 70:30 in 2015; however, the predominant race population was KJ-301 as 16%, and KI-101 as 15% in 2014 and 2015, respectively. These results indicate that the distribution of the blast races is getting more diverse in Korea, therefore, this research would provide the possibility to predict race distribution and change to prevent the outbreak of rice blast and will also serve as a useful information for breeding of resistant rice cultivar against blast.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.32 no.1
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• pp.67-77
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• 1987

To obtain basic information concerning the soybean cultivar differences of physiological and ecological responses to soil pH to select and breed stably higher yielding cultivars, and to improve cultural management of soil differing in pH, the responses of soybean plants in growth, grain yield, nodule formation and its activity, and major chemical compositions of soybean plants were investigated using six cultivars and two levels of soil pH 5 and 7 of the pot and field experimental soil in Suwon, 1985. Acidic soil condition suppressed overall vegetative growth of soybean plants and thereby decreased stem length, number of nodes, leaf area, dry weight of the plants, root activity, nodulation and nodule activity, the content of allantoin nitrogen, total nitrogen, phosphorous, calcium, and magnesium of the plants. Due to the such responses of soybean plants to the acid soil, grain yield also decreased along with less grains per plant. However, the little difference in growth and yield of the cultivar Janbaeglcong in response to soil pH is considered to be a good source of breeding materials tolerant to acidic soil condition. In this regard Bongeui and Oialkong also were relatively stable in the growth and grain yield under the different soil acidity conditions.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.63 no.3
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• pp.257-264
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• 2018

The recent global climate change induced the drought, flooding, and insect pest outbreaks. These caused the severe damage to crop yield in the domesticated field and occurrence change of insect pest species. The sap-sucking insect pest, aphids are common in soybean [Glycine max (L.) Merr.] and cause serious yield losses. Thus, developing resistance cultivars is promising and efficient strategy to prevent the significant yield losses by aphid and screening germplasm is the essential procedure to achieve this goal. We tried to establish a resistance test indicator for foxglove aphid, Aulacorthum solani (Kaltenbach), in soybean and found that plant damage degree or infested plant damage is most suitable one. Also we screened around 1,200 of soybean germplasm including wild and cultivated species for its resistance to foxglove aphid from the various origins, and 67 soybeans, including PI 366121, showed antixenosis resistance, 31 germplasms among 67 antixenosis germplasms were showed antibiosis to foxglove aphid with non-choice test. The identified foxglove aphid resistant soybean resources showed significantly low rate in survival test. Furthermore, resistance type, (i.e., antibiosis or antixenosis) of each candidate were varied. In this research, we established the screening index for foxglove aphid resistance in soybean, and identified the resistance varieties. This result could be useful resources in breeding for new foxglove aphid resistance soybean cultivars, and provide fundamental information to investigate the resistance mechanism in soybean.

• The Korean Journal of Food And Nutrition
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• v.25 no.1
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• pp.132-141
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• 2012

This current survey was conducted to examine consumer attitudes toward factors determining beef purchasing and improving distribution systems. The frequency of beef purchasing was shown to reflect social and economic status, where inhabitants in large cities, such as Seoul, with higher salaries showed a higher frequency. In addition, consumers that were in their forties bought beef more frequently than consumers that were in their twenties. Consumers in Seoul and the megalopolis with a monthly income of higher than 200 million won preferred to purchase meat from department stores and discount markets. In contrast, people in small cities with lower incomes tended to buy meat from butcher shops and brand shops. In a question regarding unsatisfaction factors of retail beef, individuals that were in their thirties with a high income had concerns associated with packaging problems. For people under thirty with low income, the consistency of quality and price were the prime concerns. In regards to the beef grading system, consumer response varied between inhabitants, monthly income and age group, where consumers from small cities that were in their twenties and forties with a low income had a negative viewpoint. For the differential beef distribution system, housewives between the ages of 30 and 40 from a small city with an income higher than 200 million won had a positive response; however, a large number of consumers were not familiar with this system. The most demanding beef cuts were in the following order: loin, flank and rib. In addition, the most important factors determining purchasing beef were as follows: price, breed and portion.

• Food Science of Animal Resources
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• v.31 no.6
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• pp.921-927
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• 2011

To compare pork quality from different pig species domesticated for Korean consumers, the meat quality characteristics of 5 different pure breeds of Landrace (L), Yorkshire (Y), Duroc (D), Berkshire (B), and Chester White (C) were determined from the 3 parts of loins, butts, and bellies. The fat content of loins was higher in breed D than in the other breeds, while that of butts and bellies was higher in breed B. The CIE color $a^*$ and $b^*$ values of the loins and butts from breed C were lower than those of the other breeds, but the color values of the belly part did not significantly differ by breed due to the high fat accumulation. The drip loss and cooking loss significantly differed depending on meat parts: breeds D and B were inferior in loins and butts but superior in bellies. The lipid oxidation of raw meat did not increase during the 7 d storage. The cooked butts of breed C had less thiobarbituric acid-reactive substances values than those of the other breeds at 7 d, and the cooked bellies of breeds D and B had less. Moreover, there were only minimal differences in fatty acid compositions by pork breed and part. From the view points of the physicochemical and organoleptic analysis of pork from different pig species, it is estimated that breed D had better meat quality in the loin part and breed B had better meat quality in the butt. The belly meat quality of breed C showed the least value. Although the meat quality of pig species differed depending on the parts and it was difficult to compare the meat quality of a part using the meat quality parameters of another part, the result of this study could provide basic information that can be used to improve the meat quality of different parts of pig species.

• The Korean Journal of Pesticide Science
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• v.15 no.3
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• pp.246-253
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• 2011

This experiment was carried out to examine the residual amount variation of carbendazim and chlorpyrifos in fruit parts of red pepper according to the open field and/or the rain shelter house. It was shown higher residual amounts of agrochemicals in the field than the house condition at two hours (0 day) after chemical application, but it was shown higher residual amounts in the house at 5 days and 10 days. Although the residual amount in the field was higher than in the house at the beginning, the chemicals fast degraded in field condition. Carbendazim and chlorpyrifos remained as time passed in order of receptacle, but the residual amounts of two chemicals in leaf at $5^{th}$ day. Carbendazim and chlorpyrifos were lessened until 10 days after chemical application, and reduction rate were 19.1% and 66.4% in flesh, 45.2% and 62.3% in receptacle, and 41.6% and 72.0% in the stalk, respectively. The reduction rate at 15 days showed 31.1%, 75.3% in flesh, 43.5%, 81.7% in receptacle, and 47.7%, 82.8% in stalk, respectively. Therefore the reduction rate of carbendazim showed receptacle > stalk > flesh, and that of chlorpyrifos showed stalk > receptacle > flesh in order. The calculated half-life of carbendazim showed 29.6 days in flesh, 13.6 days in receptacle, and 16.0 days in stalk, but that of chlorpyrifos showed 8.3 days in flesh, 8.3 days in receptacle, and 6.3 days in stalk. In conclusion, the half-life of carbendazim was longer than that of chlorpyrifos in even part, and especially was longest in flesh part of fruit.

• Journal of Animal Science and Technology
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• v.46 no.4
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• pp.509-516
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• 2004

This study is to investigate the amount of biased estimates for heritability and genetic correlation according to data structure on marbling scores in Korean cattle. Breeding population with 5 generations were simulated by way of selection for carcass weight, Longissimus muscle area and latent values of marbling scores and random mating. Latent variables of marbling scores were categorized into five by the thresholds of 0, I, 2, and 3 SD(DSI) or seven by the thresholds of -2, -1, 0,1I, 2, and 3 SD(DS2). Variance components and genetic pararneters(Heritabilities and Genetic correlations) were estimated by restricted maximum likelihood on multivariate linear mixed animal models and by Gibbs sampling algorithms on multivariate threshold mixed animal models in DS1 and DS2. Simulation was performed for 10 replicates and averages and empirical standard deviation were calculated. Using REML, heritabilitis of marbling score were under-estimated as 0.315 and 0.462 on DS1 and DS2, respectively, with comparison of the pararneter(0.500). Otherwise, using Gibbs sampling in the multivariate threshold animal models, these estimates did not significantly differ to the parameter. Residual correlations of marbling score to other traits were reduced with comparing the parameters when using REML algorithm with assuming linear and normal distribution. This would be due to loss of information and therefore, reduced variation on marbling score. As concluding, genetic variation of marbling would be well defined if liability concepts were adopted on marbling score and implemented threshold mixed model on genetic parameter estimation in Korean cattle.