• KOREAN JOURNAL OF CROP SCIENCE
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• v.25 no.3
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• pp.21-30
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• 1980

This is the fourth report in serial studies on the botanical characters of Korean maize lines collected. Several plant characters and genetical nature of lines were investigated and compared among selfed, sibbed and test crossed lines. Inbreeding depression and heterosis, and homozygosity expressed in percent were calculated. Throughout the study a great extent of variation of plant characters and genetical variation expressed in terms of inbreeding depression and heterosis were observed. The observed plant and genetic variation of plant characters were assumed to be enough for providing new breeding materials for future maize breeding program. The degree of homozygosity of Korean local maize lines suggested that a great portion of maize grown by Korean farmers presently are near or close to inbred and presumed to show a great heterosis when crossed to divergent lines.

• Journal of Sericultural and Entomological Science
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• v.7
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• pp.43-47
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• 1967

The author studied on the character of next generation which was laid from poly copulated female moth. The obtained results are as follows; 1. In the three generous two copulation, selectivity of fertilization and copulating order of silkworm showed like the two generous double copulation and their intensity of fertilization was characterized in the next generation. 2. In the next generation of silkworm, new form and character were not occurred through polygenerous poly copulation. 3. Copulating time influenced on the next generation and the time was related closely tn the copulating type (copulating order) in the three generous two copulation which was differed each copulating time.

• Korean Journal of Poultry Science
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• v.39 no.3
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• pp.245-252
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• 2012

This study was carried out to investigate the performance of laying period of two-crossbred of Korean native chickens for producing laying hens. A total of four hundred eighty female 2-crossbred chicks that restored strains and were aboriginal at National Institute of Animal Science. There were four crossbreds (4 replications/crossbred, 30 birds/replication) as A) C strain ${\times}$ Y strain, B) C strain ${\times}$ L strain, C) C strain ${\times}$ G strain, and D) C strain ${\times}$ W strain, respectively. There were no significant difference on age at first egg among crossbreds (P>0.05). Egg weight and body weight of B crossbred at first egg was higher than other crossbreds (P<0.05). Body weight of B crossbred was the highest 20 to 72 weeks (P<0.05), and C and D crossbreds were lower compared to A and B crossbreds (P<0.05). Average feed intake of B crossbred was the highest among crossbreds (P<0.05), and that of A crossbred was higher compared to C and D crossbreds (P<0.05). Weekly feed intake of four crossbreds decreased from 50 weeks. Weekly egg weight of B crossbred was the highest and that of D crossbred was the lowest among crossbreds (P<0.05). Feed conversion ratio of A and B crossbreds was lower than that of C and D crossbreds. Hen-house egg production of C crossbred was the highest among crossbreds until 26 weeks old (P<0.05), but there was no significant difference among crossbreds from at the age of 26 weeks (P>0.05). Hen-day egg production decreased after at the age of 38 weeks. Weekly egg production of A and B crossbreds was higher compared to C and D crossbreds at the age of 68~72 weeks (P<0.05). These results suggested the basic data on the record of laying period of 2-crossbreed Korean Native Chickens for producing laying hens.

• Proceedings of the Korean Information Science Society Conference
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• 2010.06a
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• pp.130-133
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• 2010

본 논문에서는 유전 알고리즘의 성능 향상을 위해 교배(Crossover) 기법의 중요 매개변수인 교배 교차점(Crossover Point)의 수를 개체군(Population)의 진화 과정 중에 적응적으로 변화 할 수 있는 자기-적응형(Self-Adaptive) 교배 기법을 제안한다. 이를 위해 제안 교배 기법은 전체 개체군을 다수개의 작은 개체군들로 군집화(Grouping)하여 일차적으로 서로 다른 교차점을 갖는 교배 기법을 적용시키고, 그 후 각 군집의 개체(Individual)들의 선택률을 기반으로 군집들간의 경쟁을 수행한다. 이는 유전 알고리즘이 개체군의 진화 과정 중에 문제에 적합한 교차점을 갖는 교배 기법을 적응적으로 사용할 수 있도록 한다. 또한 제안 교배 기법은 진화 과정 중에 교차점이 지속적으로 변화되므로 알고리즘 초반에는 높은 탐색 능력을 보유하게 되고 후반에는 높은 부분-해(Building-Block) 보존 능력을 지니게 되어, 최적 해(Optimal Solution)로의 수렴 능력이 향상된다. Deceptive 문제를 통해 제안 자기-적응형 교배 기법과 기존 (고정 교차점) 교배 기법의 성능을 비교 하였으며, 실험 결과로부터 제안 교배의 성능 우위를 확인하였다.

• The Korean Journal of Applied Statistics
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• v.14 no.1
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• pp.59-70
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• 2001

이면교배 실험은 식물이나 동물의 교배를 통해 자식계통의 유전적인 성질을 조사하는데 중용한 역할을 한다. 이면교배에 관한 기존의 연구에서는 p개의 자식계통은 하나의 집합에 속하는 것으로 간주하였다. 이와 달리 새로 육성된 자식계통의 유전적 성질을 평가하고자 하는 경우에는, p개의 자식계통이 각각 p$_1$과 p$_2$개의 자식계통을 갖는 두 개의 집합으로 분리되는 형태의 교배실험을 사용한다(단, p=p$_1$+p$_2$). 이에 본 연구에서는 자식계통이 두 집단으로 분리된 경우에 대해서 Kempthorne의 합동식을 이용하여 두 군간 교배에 대한 블록디자인을 설계하고, 이에 대한 평균효율인자를 계산하는 방법을 제안하고자 한다.

• Journal of Sericultural and Entomological Science
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• v.7
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• pp.39-42
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• 1967

The author studied on the eggs laying order of silkworm eggs which was laid by double copulation. The results can be summarized as follows; 1. Fertilized eggs were not laid in order like the copulating order. Author supposes that the sperms of the first copulated moth and second's moth were mixed in the receptaculum seminis. 2. Intensity of fertilization was mainly affected by silkworm races and copulating order, but some other factors may be acted on the double copulation.

• Korean Journal of Poultry Science
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• v.38 no.4
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• pp.293-304
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• 2011

The current work was carried out to investigate the effect of crossbred Korean native chickens (KNC) on performance and meat quality. A total of 720 chicks (1d of age) was used in this work and were divided into groups by crossbreds (A, B, C and D) and sex (male and female). Crossbreds were A) (KNC egg-meat type C strains ${\times}$ KNC meat type S strains) ${\times}$ Ross broiler, B) (KNC egg-meat type C strains ${\times}$ KNC meat type H strains) ${\times}$ KNC meat type S strains, C) (KNC native R strains${\times}$KNC meat type S strains)${\times}$KNC meat type H strains and D(White Semibroiler Chickens). Experimental diets consisted of 3 phases such as starter (0~5 weeks; CP 20.0%, ME 3,050 kcal/kg), earlier (5~8 weeks; CP 18.0%, ME 3,100 kcal/kg) and finisher (8~12 weeks; CP 16.0%, ME 3,150 kcal/kg). They were fed the broiler diets for 12 weeks at the flat house and thirty six chickens were slaughtered at week 5 and 10. There was no significant difference on the fertility of crossbred KNCs, and the hatchability of B crossbred was low compared to other crossbreds. On body weight (BW), D crossbred resulted in a higher BW after 5 weeks (P<0.05). Body weight gain (BWG) and feed intake (FI) of A crossbred were also significant higher compared to the other crossbreds for all periods. On carcass ratio (CR), A crossbred showed higher CR at 5 weeks, there was no significant among crossbreds at 10 weeks. The partial meat ratio(ala, breast, neck, leg) of C crossbred was the lowest among other crossbreds (P<0.05), but the back meat ratio was not difference among treatments at 5 and 10 weeks. pH of meats have no difference among crossbreds at 5 week, and A crossbred was high compared to other crossbreds at 10 week (P<0.05). The moisture content of D crossbred meat and the protein content of B crossbred meat were high compared to other crossbreds at 5 week. Chemical compositions of meats have no difference among crossbreds at 10 week. Lightness and redness have not significance among crossbreds at 5 week, and redness of A crossbred was the highest among all crossbreds (P<0.05). Shear force and cooking loss of A crossbred were high at 5 week, and cooking loss of A crossbred was low compared with other crossbreds at 10 week. These results suggested the basic data that needed to develope the new strains.

• Journal of Korean Society of Forest Science
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• v.98 no.6
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• pp.696-702
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• 2009

Yellow poplar (Liriodendron tulipifera L.) is an insect-pollinated tree species with large, perfect flower, and its seed sets average only about 10 percent naturally. In its controlled pollination, pollination bags are usually taken to prevent unwanted pollination, but bagging is an expensive and time-consuming process. Therefore, this study was conducted to determine the need of pollination bag by estimating how much unintended pollination would occur when different cross methods were applied. Five different pollination methods were applied as follows: 1) natural open pollination (i.e. insect pollination) as a reference, 2) self-pollination; no removing reproductive organs with bagging, 3) open pollination; emasculated(removing sepal, petal and stamen) without bagging, 4) controlled pollination; emasculated with bagging and 5) controlled pollination; emasculated without bagging. Very low value of full seed rate (0.2%) was observed in method 3, it was suggested that removing stamen and petal restrict the activity of pollen vectors like bee. Difference in the full seed rate between method 4 and method 5 was not significant (27.9% versus 24.0%, respectively). Consequently, controlled pollination without bagging might be an alternative method for extensive breeding and mass production of seeds in yellow poplar.

• The Korean Journal of Mycology
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• v.49 no.4
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• pp.487-495
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• 2021

Lentinula edodes is a tetrapolar basidiomycete and its mating type is determined by two unlinked genetic loci, A and B. Theoretically, one dikaryotic strain could produce basidiospores with four different mating types in a 1:1:1:1 ratio. Previous studies have described the skewed segregation ratio of mating types among basidiospores of L. edodes. However, they were based only on morphological characteristics, such as clamp connection, to determine mating types. To clarify whether the segregation distortion of mating types is a general phenomenon in L. edodes, we analyzed the mating types of basidiospores obtained from three cultivars of L. edodes using recently developed DNA markers. We found that the skewed segregation of mating types was strain-specific, as reported previously. Among the three cultivars, one cultivar showed balanced segregation, while the other two displayed distorted segregation. We also examined the relationship between mating type and mycelial growth rate of monokaryons derived from each basidiospore. It was found that the monokaryotic mycelial growth rate was related to the A mating type but not to the B mating type. Therefore, homeodomain transcription factor genes that reside on the A locus or other genes linked to the A locus affect the growth rate of monokaryotic mycelia. Considering the importance of mating types in mushroom breeding, this study is informative for establishing an efficient breeding strategy as well as for understanding the mechanism of monokaryotic mycelial growth.

• Korean Journal of Poultry Science
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• v.39 no.2
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• pp.133-141
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• 2012

This study was carried out to investigate the performance of laying period of two-way crossbred of Korean native chickens. A total of four hundred eighty female 2-crossbred chicks that restored strains and were aboriginal at National Institute of Animal Science. Treatments were four crossbreds (4 replications/crossbred, 30 birds/replication) as A) C strain ${\times}$ S strain, B) C strain ${\times}$ H strain, C) R strain ${\times}$ S strain, and D) L strain ${\times}$ H strain, respectively. There were no significant difference on age, egg weight, and body weight at first egg among crossbreds (P>0.05). Body weight of D crossbred was lower compared to other crossbreds at the age of 24, 32, 40 and 60 week (P<0.05). Feed intake of A crossbred was highest among crossbreds (P<0.05). Weekly egg weight of A crossbred was the highest among crossbreds all laying period except 48~52 and 60~64 weeks. Hen-house egg production of A and B crossbreds was higher than that of C and D crossbreds (P<0.05). Hen-day egg production decreased after at the age of 36 weeks. Weekly egg production of A and B crossbreds was higher compared to C and D crossbreds (P<0.05). These results suggested the basic data on the record of laying period of 2-crossbreed Korean Native Chickens.