• Journal of Sericultural and Entomological Science
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• no.12
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• pp.17-20
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• 1970

Occasionally, We make mistake of discrimination of sex since a pair of small spots around tile abdomen of 9th abdominal of males and posterior spots of females of the silkworms larvae are found at almost same position. As already have reported, more larvae which have the small spots were found in Chinese race than the Japanese. This research has been conducted in order to grasp the rate of appearance of the small spotted larvae hereditarily when hybridize with different race (F$_1$) 1. According to the first report, average 17,8％ of the small spotted larvae are found in the Japanese race and 57.0％ in the Chinese, but my re-invested data which was carried out recently shows that average 13.6％ in the former case and 37.8％ in the latter. Those new data are supposed to be come to a conclusion that the figures are flexible but in any case high frequency of appearance of the larvae were found in the Chinese race than the Japanese (Reference Table 1 ) 2. Miscalculated ratio of the larvae from males to females are 1.2-2.6％, and from females to males are found 0.5％-0.9％ in the Japanese race, In case of the Chinese race, 7.1-9.4％ in tile former and 2.9-3.4％ in the latter. Those data also shows that more of the larvae found in Chinese race. 3. The larvae of small spotted and non-spotted are also seperated when hlybridize with different mating types and races. 4. More small spotted larvae are seen when hybridize with less appeared of the small spots of females and males which have the small spots than more appeared of the small spots of females with none spotted of the males (Reference Table 2. C.G.)B.F.). 5. More larvae of the small spots and found in case of hybridize in a group of having small spots than none of the spots (H>E). 6. With the exception of the case (A.B), in the same type of cross breeding (C.D, E.F, G,H), more larvae of the smal1 spots are also found in case of hybridize with males of having the spots than none of the spots.

• 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.43 no.4
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• pp.207-212
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• 2016

This work was carried out to investigate the ability of thirteen crossbreds for production of commercial chicken (CC) of Korean native chicken to be cut out for Korean circumstance. Total of one thousand three hundred of crossbreds were divided thirteen groups (100 birds/group) that were twelve groups (1A, 1B, 2A, 2B, 3A, 3B, 4A, 4B, 5A, 5B, 6A, 6B) to crossbreed with two sires (A, B) and six dams (1, 2, 3, 4, 5, 6) of parent stock (PS) of Korean native chicken and one group (HH) as commercial Korean native chicken. Experimental diets were starter diet (0~7d; CP 22.0% ME 3,150 kcal/kg), early diet (8d~Wt 800 g; CP 19.0% ME 3,150 kcal/kg) and finished diet (Wt 800 g~12 wk; CP 18.0% ME 3,150 kcal/kg). Fertility of 1B group was higher than other groups. Hatchability per fertilization eggs and hatchability per setting eggs were 87.5~89% and 87.9~96.3%, respectively, and those of 4B and 6B groups were lower compared to other groups. Weekly body weight of HH group was lower than other groups. CV values of body weight of thirteen groups were showed over 12% as 12.5~18.2%, and especially, those of 2B, 3B, 5B, HH groups were lower compared to other groups. Weekly feed conversion ratios (FCRs) of 13 crossbreds were 1.7~2.3, 2.1~2.5, 2.4~2.7 and 2.7~3.2 at the age of 6, 8, 10 and 12 weeks, respectively. Weekly production indexes of 2A, 3A and HH groups were the lower than other groups and those of thirteen groups decreased following weeks. Feed costs per body weight gain (kg) were 1,069~1,255 won, 1,100~1,263 won, and 1.468~1,696 won at starter, earlier and finished period of broilers. These results leaded down to conclusion to be possible selection of new Korean native commercial chicken that have the excellent performance and economics.

• Korean Journal of Breeding Science
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• v.41 no.2
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• pp.106-114
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• 2009

In maize, knowledge of genetic diversity and genetic relationships among elite inbred lines is an significant impact on the selection of parental lines for hybrid varieties. Genetic diversity and genetic relationships among 11 parental inbred lines of Korean waxy and normal corn varieties were analyzed using 50 SSR markers distributed over the whole genome. A total of 171 allele bands were detected with an average of 3.4 alleles per locus. Number of allele bands per locus ranged from two to six and gene diversity varied from 0.165 to 0.900 with an average of 0.596 depending on the SSR loci. The cluster tree recognized three major groups with 61.6% genetic similarity. Group I includes 7 inbred lines (KL103, HW1, HW4, HW6, HW7, HW8, HW9), with similarity coefficients of between 0.616 and 0.730. Group II includes 2 inbred lines (HF1, HF2), with similarity coefficients of 0.959. Group III includes 2 inbred lines (HW3, HW5), with similarity coefficients of 0.713. The present study indicates that the SSR markers chosen for this analysis are effective for the assessment of genetic diversity and genetic relationships among 11 parental inbred lines.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.23 no.2
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• pp.25-33
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• 1978

7 parent varieties and 21 $_{x}\textrm{F}_1 and $_{x}\textrm{F}_2 hybrids from 7 X 7 partial diallel crosses were used as the materials, and degree of heterosis was studied in 9 agronomic characters of rice. Degree of heterosis was more remarkable in $_{x}\textrm{F}_1 hybrids than $_{x}\textrm{F}_2 hybrids. and significant differences were showed in many hybrid generations. and also over dominance could be shoo wed in eight characters except 1000 kernel weight of rice.

• Journal of Life Science
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• v.26 no.10
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• pp.1218-1223
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• 2016

Abalones are gastropod mollusks belonging to the genus Haliotis. Fishery products are continuously declining worldwide while abalone production from aquatic farms has considerably increased. Although abalones are regarded as very important marine resources and considered to have big potential in sea-food farming industry around world, the slow growth rate of Pacific abalones is considered to be one of the most serious problems. For the genetic improvements in cultured abalone, advances in various breeding techniques for abalone have been reached through the introduction of selection, crossbreeding, hybridization, and polyploidy in several commercially important abalone species. Six species of abalone have been reported to be distributed along the coasts of Korea: Haliotis discus hannai, Haliotis discus discus, Haliotis madaka, Haliotis gigantea, Haliotis diversicolor diversicolor, and Haliotis diversicolor supertexta. The hybridization between these abalones may be one of the advanced technologies, and the preliminary experiments of interspecific hybrids between abalone species distributed in northern pacific areas including Korea, China, and Japan have been conducted. In this study, we reviewed the phylogenetic relationship of northern pacific abalone species which have the potential traits for aquaculture in Korea and their identifications. We also examined the development of molecular markers and some other aspects of the genetic approaches for successful development of hybrids.

• Journal of Life Science
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• v.15 no.1 s.68
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• pp.33-37
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• 2005

Sasa borealis Makino is distributed in East Asia such as Korea, Fushun in China, and Japan. Especially the species is only found in the high altitude (above 600 m) at mountain of cold regions including The Korean Peninsula. The level of genetic diversity and population structure of this species was surveyed using starch gel electrophoresis at putative five enzyme loci from three natural populations in Korea. Results from twelve loci indicated that genetic diversity was low. In addition, analysis of fixation indices revealed a substantial heterozygosity deficiency in some populations and loci. The reasons for the deficit of heterozygosity may be partly considered inbreeding, small population sizes, and mating of demes. S. borealis can reproduce extensively by producing rhizomes and potentially by sexually produced seeds. Rhizomes are generally long, prostate stems rooting at the nodes.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.2
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• pp.175-184
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• 1995

In order to substitute sweet and super sweet maize hybrid seeds which are introduced at current, and to meet national demand for human consumption, inbreds and hybrids of waxy maize were developed by using Korean native lines, Six inbreds were used to produce 15 hybrids in a diallel cross, Six inbreds used were significantly different in tasseling dates, plant and ear heights, leaf area, and shank length, The inbred line, Bosung showed the longest shank length among the lines used, The ear characters like ear length and diameter, 100 kernel weight, row number, and kernel number per ear varied among lines, The inbred line Bosung was again significantly different from other lines in ear length and diameter, row number and 100 kernel weight. However, ]ewon had the highest kernel yield per 100. Hybrids were also different in plant and ear characteristics depending upon the inbreds used. The hybrids of Bosung showed the longest ear length and the heaviest kernel weight. Highest kernel yield per unit area was obtained by the hybrids crossed with Dangjin, The general combining ability(GCA) of Dangjin was found very effective in reducing plant and ear height of hybrids. The GCA of Jewon was very effective in increasing tiller number per plant. The inbred line Bosung was effective in increasing ear length and 100 kernel weight and in decreasing row number. The hybrid which showed the highest specific combining ability in ear length and 100 kernel weight was Jewon Chilbo.

• The Korean Journal of Mycology
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• v.24 no.4 s.79
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• pp.237-245
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• 1996

Esterase isozyme band patterns were compared between the wild strain and commercial strain of Flammulina velutipes. Monospores were isolated from wild strain. ASI4019 and their mating types were determined. We investigated the relationship between pigmentation on the plate and fruitbody color to understand genetic relationship among F. velutipes strains. Dikaryotic strains mated between nonpigmenting strains produced white fruitbodies. However dikaryon obtained from mating between nonpigmenting monokaryon and brown pigmenting monokaryon produced brown fruitbody as the dikaryon obtained from mating of brown pigmenting monokaryons. The white fruitbody from wild strain was distinguished from that of commercial strain. When the nonpigmenting wild monokaryon was mated with commercial monokaryon, pale brown mushroom was produced. The BC1F1 was obtained by mating the above mentioned $F_1$ with commercial monokaryon. Fruitbody color of BC1F1 shared two types; one strain with all pale brown fruitbodies, and the other strain with separated eight pale brown and two mixed type involving pale brown and white fruitbodies.

• Korean Journal of Poultry Science
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• v.41 no.1
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• pp.39-44
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• 2014

The goal of this study was to evaluate the growth performance of crossbred strains using Korean native chicken (KNC). The data were collected from 2012 through 2013 at Poultry Science Division, National Institute of Animal Science, Korea. The number of chicks analyzed in this study was 375. Crossbred were (A) $R{\times}S$, (B) $D{\times}H$, (C) $D{\times}S$, (D) $C{\times}Y$ and (E) $Y{\times}H$. The fertility rates of strains were 94.9% in crossbred A, 91.9% in crossbred B, 91.8% in crossbred C, 89.7% in crossbred D and 93.8% in crossbred E, respectively. The fertility was highest in crossbred A, but crossbred C showed the lowest (p<0.05) based on the hatchability. The crossbreds B and C exhibited a superior performance on body weight gains during growing stages but crossbred D showed the lowest (p<0.05). The feed intake was to the pattern of body weight. The feed intake of crossbred D was significantly lower than other crossbreds. Also, feed conversion ratio of crossbred D showed the lowest (p<0.05). Egg production ratio of crossbred D was significantly higher compared to the other crossbreds. These results suggest that the development of new crossbreds of commercial Korean Native Chickens should be required for better performance.