• Korean Journal of Plant Resources
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• v.17 no.3
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• pp.304-313
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• 2004

This study was conducted to find out the scientific maize breeding protocol for developing high performing single cross hybrid using introduced U.S. elite inbred lines; the pattern of inheritance, heterosis and heritabilities of six agronomic traits were studied in the progenies derived from five crosses (Mo17/B14A, Va85/B73, C103/ND203, FR35/Oh43, Wf9/A632). Among the five cross combinations, the cross combination of Mo17/B14A showed the highest heterosis for the most agronomic traits. Among 6 agronomic traits, the grain yield showed the highest heterosis effect in most cross combinations. Most of the agronomic traits in this study showed more than 50% heritability for six cross combinations, with an exception of the ear length trait. In conclusion, since Mo17/B14A showed excellent performance for most of the agronomic traits, these inbred lines were desirable combination and regarded as superior germ plasm sources for F1 hybrid development. The results of current studies will be utilized for developing high performing single cross hybrid from maize inbred lines, and will be used for the further genetic analysis of agronomic traits and maize breeding programs.

• Journal of Mushroom
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• v.1 no.1
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• pp.9-14
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• 2003

To breed new superior strains, collected strains were characterized and then several white strains were selected as parents. Monokaryons from the parents were isolated and studied. All tested white strains showed same mating genotype. Growth rate of monokaryons were lower than collected dikaryons. New dikaryotic strains were derived from inbreeding method, which means mating between monokaryotic isolates from different white strains having same mating genotype. Some of them showed higher yields of fruitbody than their parents. Specially Fv 4-1 strain showed the best productivity. Furthermore some mating combination showed cytoplasmic effect, when they mated reciprocally.

• Korean Journal of Poultry Science
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• v.12 no.2
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• pp.75-82
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• 1985

This study was carried out to estimate combining abilities and heterosis in White Cornish and White Plymouth Rock. The data were obtained over an 8weeks period from 3rd Oct., 1984 to 28th Nov. 1984 at the Livestock Experiment Station. A total of 810 birds, composed of 369 pure strains, 270 two-way crosses, and 180 fourway crosses were average amount of heterosis expressed as a ratio was 1.63% for livability, 5.47% for body weight at 8 weeks, 5.57% for weight gain from day old to 8 weeks and -5.98% for feed requirement. Specific combining ability were statistically significant for all of the traits examined in this study. Although the general combining ability was not significant for any of the traits, strain A appears to be superior to other strains.

• Journal of Sericultural and Entomological Science
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• v.14 no.2
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• pp.61-65
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• 1972

The main purpose of this experiment is to select the best combining ability among KC${\times}$N13, and C20${\times}$N13 in view of the cocoon shell weight in Bombyx mori. In the spring of 1972, the author raised silkworms which were born from the crossing of the Chinese strain KC, C14, C20(female) with japanese strain N13 (male). Among each combining of crosses, the heritability of the cocoon shell weight was estimated by the method of variance analysis. The result of the experiment may he summarized as fellow; 1. For KC${\times}$N13 The cocoon shell was heavier than other combining crosses, but its heritability was lower than the others. The heritability of male moth was higher than that of female. 3. For C14${\times}$N13 The cocoon shell and the heritability was in medium value among the combining crosses, and the heritability of female moth was higher than that of male. 3. For C20${\times}$N13 The cocoon shell weigt was lower than the others, but its heritability was higher than that of others. In these combining crosses, C20${\times}$N13 is selected as a new race, which is much better than the commercial one, 103${\times}$104.

• Korean Journal of Poultry Science
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• v.45 no.2
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• pp.125-135
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• 2018

This study was conducted to evaluate the productivity and meat quality of three newly-developed crossbreds of Korean native chicken (2A, 2C, and 2D) as compared with commercial Korean native chicken (CKNC) and commercial broiler. Totally, 400 birds of different crossbreds were randomly allotted to eight pens, each with 50 birds. The birds were reared ad libitum and slaughtered at the age of 12 weeks. Fifty male chickens were slaughtered at the same day in the same slaughterhouse were selected for the comparison of meat quality. The crossbred 2C had greater body weight than that of CKNC (P<0.05), and had similar uniformity with lower death rate. Although shank length of 2C was the longest among the Korean native chicken breeds, the ratio of shank length to body weight was the lowest among them (P<0.05). The crossbred 2C had similar inosine 5'-monophosphate (IMP) content as that of CKNC in breast meat, and the highest IMP content in thigh meat (P<0.05). In a sensory analysis, the crossbred 2C generally showed, similar savory taste and texture as that of CKNC, and the overall acceptability of thigh meat was the highest in CKNC and broiler. Based on the present results, the possibility of commercialization of a newly-developed crossbred of Korean native chicken was confirmed.

• 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.

• Journal of Mushroom
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• v.18 no.4
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• pp.331-338
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• 2020

This study was conducted to cultivate new Lepista nuda varieties with shorter cultivation period and better fruiting body compared to that of wild strains, for mass production and commercial application. Eighteen genetic resources of L. nuda were collected and grown in boxes using rice straw-fermented growth medium. Four lines with fruiting bodies were formed and selected as cross-breeding lines. Although 657 combinations were crossed through monospore crossing, only 17 combinations were bred between the 'CBMLN-19' line and the 'CBMLN-30' line. Among them, 8 lines with fast mycelial growth and high density were selected. After inoculating the rice straw-fermented growth medium with 14 genetic resources and 8 cross-breeding lines, their incubation period was investigated. Six of the cross-breeding lines completed their incubation in 20 days, while 7 of the 14 genetic resources took more than 40 days to complete their incubation, reducing the incubation period by more than 20 days in most cross-breeding lines. After the incubations were completed, the clay loam soil was covered with for post-cultivation, and when the mycelial cultivation was complete, the formation of fruiting bodies was induced after scraping the mycelial bodies under these environmental conditions: 14℃, 95% relative humidity or higher, and 1,500 to 2,000 ppm CO2 concentration. The temperature was reduced to 6℃ at night, resulting in a low temperature shock. Thus, 4 lines of fruiting bodies occurred from two genetic resources 'CBMLN-31' and 'CBMLN-44' and two cross-bred lines 'CBMLN-96' and 'CBMLN-103'. After inoculation, the longest period for fruiting bodies to occur was 100 days for the control:, the genetic resource 'CBMLN-31', and the shortest period (45 days) was observed for the cross-breeding line 'CBMLN-103'. The result of the investigation of the fruiting body characteristics shows that the cross-bred line 'CBMLN-103' showed a small form with 1.9 g of individual weight and 123validstipes per box, which was the highest incidence among the four lines. Another cross-bred line, 'CBMLN-96', had an individual weight of 5.5 g, which is larger than that of 'CBMLN-103'; however, the number of valid stipes per box was 30 less than that of 'CBMLN-103'. Quantity analysis showed that the control, 'CBMLN-31', had the highest quantity of 783 g per box, followed by the cross-bred line, 'CBMLN-96' with 165 g per box, and then the 'CBMLN-103' with 232 g. The quantity of the two crossbred lines was lower than that of the control 'CBMLN-31'; however, the amount of fruiting bodies was higher, and the cultivation period was shortened by 32 to 33 days. Therefore, these two lines would be selected as superior lines.

• Research in Plant Disease
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• v.16 no.2
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• pp.153-157
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• 2010

This study was examined to identify the race differentiation and distribution of mating type on Phytophthora capsici population in Korea. One hundred forty three isolates of P. capsici were collected from several locations of Korea in 2005-2007. In 2005, 20 isolates of P. capsici were collected and surveyed as A1 mating type of 75% and A2 mating type of 25%. In 2006, a total of 91 isolates were collected and separated as A1 mating type of 49.0%, A2 mating type of 42.9% and S type (sterile) of 3.3%. Isolates obtained in 2007 were similar to 2006 results. Totally, ratio of mating type of 153 isolates was confirmed that A1 type was 56.6%, A2 type was 39.2%, and S type was 4.2%. Thirteen pepper cultivars with different pathogenic response to 3 typical isolates having different mating were screened among 50 pepper cultivars and determined as race differential cultivars for investigation. The 11 races of P. capsici were found by using 13-race differential cultivars. These results indicated that at least 11 races of P. capsici are existed and confirmed race differentiation of P. capsici in pepper.

• Horticultural Science & Technology
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• v.33 no.5
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• pp.712-721
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• 2015

To improve the breeding efficiency of oriental pear, heritability, correlation and frequency distribution of fruit ripening date were analyzed using 4,035 seedlings obtained from 15 families between 13 parental cultivars. Although variation of fruit ripening time was higher in most early-ripening parental cultivars than in late-ripening parental cultivars, according to analysis of average, standard deviation, and coefficient of ripening variation for ten years, fruit ripening time obtained from all parental cultivars was inherited narrower and more stable variation than others fruit trait, with 0.92-3.41 in coefficient of variation. The heritability of fruit ripening time was calculated to be over 0.8 in almost all crosses and average fruit ripening time of seedlings from cross combinations could be predicted based on that of the parental cultivars due to its superior heritability relative to other fruit traits. The average ripening time was earlier than the mid-parental value in families obtained from cross combinations using at least one late-ripening cultivar as parent, indicating that the early-ripening trait was more likely to be dominant compared to the late-ripening trait. By contrast, average ripening time was clustered in families of crosses not only between mid-season and early-season cultivars, but also between mid-season and mid-season cultivars. There was highly significant relationship (at 0.68) between mid-parental and progeny mean fruit ripening time. The correlation between fruit ripening time and fruit weight was also highly positive and thus, the mid-parental fruit ripening time could be a potent criterion for indirect selection of fruit weight.

• The Korean Journal of Mycology
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• v.51 no.4
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• pp.389-396
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• 2023

In this study, dikaryotic strains of Lentinula edodes were generated by mono-mono hybridization using mating type analysis and their fruiting body characteristics were investigated. Approximately 100 monokaryotic strains were isolated from the basidiospores of Sanbaekhyhang, and homokaryotic strains were isolated from Chungheung 1ho using protoplast isolation and regeneration. Their mating types were evaluated and a total of 60 dikaryotic strains were hybridized. Using these strains, fruiting bodies were produced and their characteristics were examined after cultivation on sawdust media. The results indicated that the rate of hybridization was 100% and that 55 of 60 strains formed fruiting bodies. These showed normal pileus and gill structures; however,10 strains also produced fruiting bodies with abnormal pileus and gill structures. The weight and size of the fruiting bodies differed depending on the strains. Overall, further studies are needed for predicting the characteristics of hybridized strains based on their parental strains.