• Korean Journal of Poultry Science
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• v.40 no.1
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• pp.17-23
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• 2013

This work was carried out to investigate the performance of early laying period of large-type Korean native ducks. One hundred sixty eight ducks were used in this work and divided into A and B strains (6 replications/strain, 14 birds/replication). The days at first egg of A and B strains were the age of 154.5 and 154.7 days, egg weights were 69.1 g and 65.5 g, and body weights were 3,187 g and 3,105 g at the period of laying the first egg, respectively. The days at sexual maturity of A and B strains were the age of 175.8 and 171.5 days, egg weights were 75.2 g and 74.9 g, and body weights were 3,245 g and 3,225 g at the period of laying the first egg, respectively. There were no significant differences on the day of first egg, the day of sexual maturity, egg weight and body weight at first egg and the sexual maturity, average body weight, and daily feed intake between A and B strains (P>0.05). The day of the sexual maturity of B strain was earlier than that of A strain (P<0.05). However, weekly body weight was the highest at the age of 28 weeks (P<0.05), and weekly feed intake increased after 26 weeks old (P<0.05). Egg production (%) of B strain was higher than that of A strain at the age of 22~24 weeks (P<0.05), but there was no significant difference on egg production (%) the other weeks. A number of egg laid of B strain was higher than A strain at 22~24 weeks old (P<0.05). Feed conversion ratio of A and B strains were 10.7 and 6.53 at 24~24 weeks old, respectively, so feed conversion ratio of A strain was higher than that of B strain (P<0.05). Weekly feed conversion ratio wes the highest at 20~22 weeks old, and significantly decreased until 24~24 weeks old, but were lowly maintained from the age of 24 weeks to the age of 30 weeks. These results provided the basic data on the record of early laying period of large-type Korean native ducks.

• Korean journal of applied entomology
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• v.4
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• pp.29-32
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• 1965

1. The 30 isolates of Xanthomonas oryzae collected from various places in Korea were classified into 2 strains in A' and B, by the 4 kinds of Japanese bacteriophages as follow; A' strain; Susceptible to $OP_1$ and $OP_2$ but not to $OP_1h$ and $OP_1h_2$. B strain; Susceptible to $OP_1h$, $OP_1h_2$ and $OP_2$ but not to $OP_1$. Of these bacterial strains, A' strain, a little different to A strain in Japan, was susceptible to $OP_1h_2$, while A' strain was resistant to $OP_1h_2$, 2. A' strain was widely and commonly distributed throughout this country, In geographical distribution, it was generally known that A' strain was distributed in south of Kyunggi-Do, whereas B strain was distributed north of Suwon area. 3. No specific tendency was found in the distribution of these strains in same variety.

• Korean Journal of Poultry Science
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• v.40 no.3
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• pp.217-222
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• 2013

This work was carried out to investigate the performance of large-type Korean native ducks at middle laying phase (30 to 50 weeks). A total of one hundred and sixty eight laying ducks were divided into A and B strains (6 replications/strain, 14 birds/replication and fed practical diet, for 20 weeks). There was no significant difference in body weight, daily feed intake and average egg weight. With increasing rearing period, mean body weight tended to be decreased and showed the lowest value (2,649 g) at 42 weeks of age (P<0.05). Similar trend was observed for weekly feed intake and average egg weight which decreased with passing weeks and was lowest (190.5 g and 83.8 g, respectively) at the age of 42~46 weeks (P<0.05). Daily egg production of B strain was higher than that of A strain at the age of 46~50 weeks (P<0.05). Weekly egg production of A and B strains commenced to decrease from the age of 42 weeks, however, B strain recovered at 46~50 weeks of age (P<0.05). At the age of 30~38 weeks, the egg production in B strain was higher than A strain (P<0.05), whereas, there was no significant difference between both the strains during 38~50 week. Feed conversion ratio of A strain was higher than that of B strain at 46~50 weeks of age (P<0.05). Weekly feed conversion was highest at the age of 42~46 weeks (P<0.05). In conclusion, the present results provides the basic information of the performance record of large-type Korean native ducks for the middle laying phase.

• 전기의세계
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• v.13 no.4
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• pp.60-74
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• 1964

계통의 발전력 및 송전용량이 계통부하에 비하여 어느정도 여유를 가지게 될때 그 부하를 각 발전소에 어떻게 분담시키면 가장 경제적일가 하는 계통의 경제적 부하배분 문제가 커다란 의의를 가지게 된다. 그동안 우리나라에서 전원개발에 꾸준하게 노력한 결과 전력사정이 어느정도 유급의 균형을 잡을 수 있을 만큼 완화되었고 또 앞으로의 전망도 금년 여름부터라도 상기의 경제적 급전을 실시할 수 있는 단계에 이르렀다함은 퍽이나 반가운 일이다. 본 문은 불환 실시된 계통의 경제적 급전에 대비하여 그 기초재료로서 소요되는 loss formula coefficients (B constant)를 주로 digital computer를 이용하여 산정한 것이다. 사용한 계통원 및 각종 재료는 직접 한국전력에서 보내온 것이다.

• Korean Journal of Poultry Science
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• v.37 no.4
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• pp.399-404
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• 2010

This work was conducted to evaluate the hatching and growing performance of Korean native chicken (KNC) 3 strains crossbred. A total of 360 female pullets were produced from $\times$ (A), CL $\times$ C (B), CG $\times$ C (C) and CW $\times$ C (D) crossbred kept in National Institute of Animal Science, Korea. Hatchability of A, B, C and D were 69.8, 70.7, 75.5 and 77.4%, respectively. Livability were not significantly different by 20 weeks among 4 strains. Body weight B was high compared to other strains at 20 weeks. The feed conversion ratio of 4 strains was no significantly different among strains at 20 weeks. These results suggested the basic data that needed to develope the new strains.

• Korean Journal of Poultry Science
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• v.41 no.1
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• pp.69-75
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• 2014

This study was carried out to investigate the performance of laying period of A and B strains of Korean native ducks (KND). One hundred sixty eight ducks were used in this work and divided into A and B strains (6 replications/strain, 14 birds/replication). Ducks were fed with laying ducks' feedstuff (CP 15%, ME 2,900 kcal/kg) for the age of 20~80 wk old. There was no significant difference on body weight, feed intake and egg weight between A and B strains. Weekly body wt of KNDs was the lowest at the age of 40~48 wk old, and that of those was high at the age of 24~32 wk and 64~80 wk old (P<0.05). Weekly feed intake significantly decreased at the age of 36~48 wk and 68~72 wk old (P<0.05), but there was no significant difference at the age of 52~56 wk old. Weekly egg wt was the lowest at the age of 32~40 wk old. Egg production ratio of B strain was higher compared to that of A strain at the age of 24~28 wk, 60~64 wk and 20~80 wk old. Weekly egg production ratio was the highest at the age of 28~32 wk old, and was high maintained until the age of 48 wk old. However, weekly egg production ratio decreased from the age of 52 wk old to the age of 68 wk old. Number of egg of B strain (267.5) was higher than that of A strain (235.6) at the age of 20~80 wk old. There was no significant difference on feed conversion ratio between A and B strain at the age of 28~36 wk old, but feed conversion ratio of A strain was higher than that of B strain at the other weeks (P<0.05). These results provided the basic data on the record of laying period of Korean native ducks.

• Korean Journal of Plant Resources
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• v.35 no.5
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• pp.659-666
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• 2022

The effect of rye B chromosome (rye B) on chromosome association was investigated in meiosis of wheat addition line. The wheat addition line was with one Leymus mollis chromosome and one L. racemosus chromosome which are under homoeologous relationship. Chromosome behavior of the two Leymus chromosomes in wheat genetic background was revealed by genomic in situ hybridization. In the first metaphase, most of the two Leymus chromosomes showed univalent in the wheat addition line without rye B (98.1 ± 0.5%). On the other hand, the wheat addition line with rye B showed higher frequency of bivalent (10.3 ± 0.2%) than wheat addition line without rye B (1.9 ± 0.5%). The wheat addition line without rye B showed abnormal bivalents with abnormal structure while the wheat addition line with rye B showed normal bivalent in low frequency. By rye B, some bivalent was composed of wheat and L. racemosus, and some trivalent was composed of wheat bivalents with L. mollis chromosome. Also, some wheat bivalents showed hyper-crossover, so those wheat bivalents showed abnormal structure compared to other wheat bivalents with normal structure such as ring, rod, and pan.

• Korean journal of applied entomology
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• v.44 no.3 s.140
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• pp.169-175
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• 2005

The occurrence of tobacco whiteflies, Bemisia tabaci, in greenhouses was monitored in Korea in 2005. Bemisia tabaci occurred in the rose, sweet pepper, tomato, and cucumber greenhouses of Chungbuk, Chungnam, Gyongnam, and Jeonnam Provinces, but not in Jeonbuk and Gyongbuk Provinces. The biotypes and genetic differentiation of the whiteflies collected in each regions were analyzed by mitochondrial 16S DNA sequences. The 16S DNA sequences of Jincheon (Chungbuk Province) samples were similar to DNA data reported from Japan and Israel which were known as the B biotype. However, the DNA sequences of the Buyeo (Chungnam), Geoje (Gyongnam) and Boseong (Jeonnam) collections, which were 100% homologous showed over 99% similarity to the DNA of Q biotype from Spain and Egyrt. Here we report the first founding of the Q biotype in Korea. It is assumed that, unlike the B biotype reported from Jincheon since 1998, the Q biotype might have been introduced recently from the certain foreign region/country to the greenhouses in those provinces.

• Proceedings of the KIEE Conference
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• 2007.11b
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• pp.156-158
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• 2007

전력계통의 단락 용량의 증가는 고장 발생시 계통의 안정성을 저해하고 심각한 전압 강하를 유발시킨다. 계통운영을 안정적으로 도모하기 위해서는 고장 전류의 억제가 무엇보다 중요하며 초전도 한류기의 설치의 필요성에 관한 연구가 활발히 진행되고 있다. 초전도 한류기를 계통에 적용하기 위해서는 우선 투입 시 계통에 미치는 영향의 검토가 우선되어야한다. 본 논문에서는 EMTP-RV 를 사용하여 배전 계통 및 초전도 한류기(SCFCL)를 모델링하고, 초전도 한류기 투입 위치에 따라서 계통의 영향을 모의 하고 분석 하였다.

• Korean Journal of Poultry Science
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• v.20 no.1
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• pp.1-9
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• 1993

This study carried out to build up new synthetic egg production lines which had sex-linked gene for feather color sexing and also superior combining ability for producing the best commercial chicks. The closed flock breeding method was utilized to improve the general performances in the first experiment and combining ability for heterosis was tested for new synthetic line in the second experimental year. In order to test for the egg production ability in cross breeds synthetic lines, the crossing of B$\times$4 B$\times$C, two imported strains and two domestic strains as controls were compared for the general performances. There was on difference in mortality, body weight to 56 weeks of age. Sexual maturity was delayed about 10 days by comparing with other reports, except 153 days of the Manina White, but no difference among mating systems in this experiment. The hen housed egg production in B$\times$A, B$\times$C was 186.3, 191.3 respectively and it was better than the other controls, except ISA imported lines. The hen-day egg production of B$\times$A, B$\times$C was better than other controls, with 75.7%, 76.8% respectively. In the average egg weight, the B$\times$C cross breed was highest with 64.5g. As the sex of hatching chicks was identified by difference of feather color, the genetic composition of synthetic lines must be homogenized. The feather color of female chicks was brown and that of male was silver (99%), In conclusion, the egg production ability of B$\times$A, B$\times$C cross breeds was superior to the imported and domestic lines. Therefore, it suggest that the synthetic lines with sex-linked gene might be utilized for improving egg production performances.