• 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.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.33 no.4
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• pp.386-391
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• 1988

Five barley crosses and their progenies (F$_2$, F$_3$, and F$_4$) were evaluated the potentiality of hybrid populations to segregate superior yielders in later generation. Four characters used for evaluation were number of spike, number of grain, spike weight and grain weight per plant. Superiority value (Y) of number of spike was best in SB76588${\times}$SB72648 and average of superior plants in F$_4$, was excellent in this cross. Milyang 6${\times}$Suwon 203 showed high Y value and average of F$_4$ superior plants in the number of grain. Spike weight showed the highest Y value and excellent averages of superior plant in Milyang 6${\times}$Suwon 203. Superiority value of grain weight per plant coincided with average of F$_4$ superior plants in 3 crosses and SB76588${\times}$SB72648 was the best among the crosses.

• 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.

• Horticultural Science & Technology
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• v.34 no.5
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• pp.761-770
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• 2016

This study investigated the variation in fruit characteristics between different triploid progenies derived from a cross between tetraploid and diploid grape cultivars, with the aim of developing high quality, labor-saving triploid grapes. No differences were found in fruit quality traits such as soluble solids content and titratable acidity, whereas significant variation was noted in cluster weight induced by a one-time application of GA3 (100 ppm) on the triploid progeny of different cross combinations. The cluster weight was higher in progeny obtained from 'Kyoho' ${\times}$ 'Sekirei' than for offspring derived from other cross combinations; deviation in the mean cluster weight was also small for 'Kyoho' ${\times}$ 'Sekirei' progeny. These results suggest that specific cross combinations, such as 'Kyoho' ${\times}$ 'Sekirei', can be used to efficiently breed new, labor-saving seedless grape cultivars.

• 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 Plant Tissue Culture
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• v.25 no.3
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• pp.165-169
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• 1998

Anthers of three cross combinations of hot-pepper(Capsicum annuum L.) were cultured on Dumas De Vaulx medium supplemented with some growth regulators. The embryo production efficiency and the diversity for agronomic traits in $A_2$ lines were investigated. The embryo production frequencies of hybrid combinations were ranged from 16.4% to 43.4%, the highest embryo induction combination was DGSH $\times$ C-NH with 43.4% embryogenic efficiency. Among total 275 $A_2$ lines, phenotypic variants were found in six lines, 2.1% variant frequency. The diversity of $A_2$ lines derived from anther culture was different according to the cross combinations. Fruit color was within parental range, no transgressive variation was observed. However leaf color showed transgressive variation. In fruit length, fruit width and fruit weight, one C-HC $\times$ DGSH and DGSH $\times$ C-NH showed great diversity compared with doner parents while Cheokjo 1 $\times$ C-NH crossed with Cheokjo 1 with big fruit shape showed small diversity. Stem length to 1st branch was relatively similer to or longer than donor parents. Stem thick exhibited remarkable diversity. Node number to 1st branch distributed alomost within the range of donor parents in C-HC $\times$ DGSH combination, however great transgressive variations were observed in DGSH $\times$ C-NH and Cheokjo 1 $\times$ C-NH combinations.

• Journal of Korean Society of Forest Science
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• v.75 no.1
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• pp.55-66
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• 1986

A complete diallel cross using ten varieties of Corylus avellana was made to select the best general combiners and the best specific combiners for each characteristic of each variety. The variety "Barcelona" showed the best general combining ability in kernel yield per hectare and the combinations, between Kara and Badem, between Badem and Barcelona, between Sivri and Barcelona, between Sirri and Barcelona, between Palaz and Barcelona, between Tombul and Kara, between Barcelona and Sivri, between Fiukuken2 and Hukuken3, and between Hukuken3 and Hukuken2, showed the best specific combining abilities in kernel yield. The other characteristics such as fruiting rate, pericarp thickness, weight/nut, kernel weight/nut, kernel ratio, and kernel yield per tree or hectare were also compared between the combinations.

• Korean Journal of Poultry Science
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• v.38 no.4
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• pp.331-338
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• 2011

The study was conducted to evaluate the production and the performance test of egg-type commercial Korean Native Chickens. A total of 360 female layers were produced from CY${\times}$C (A), CL${\times}$C (B), CG${\times}$C (C) and CW${\times}$C (D) crossbreds kept at National Institute of Animal Science, Korea, and breed during 20~64 weeks to investigate the productivity and the performance. Layers were divided into 4 crossbreds (6 replications/crossbred, 15 heads/replication). Age and egg weight at first egg was no significantly different among crossbreds. Body weight (BW) at first egg of D crossbred was significantly lower compared to that of other crossbreds (P<0.05). Weekly BW of B crossbred was the highest at 20, 30 and 40 weeks of age, but BW of D crossbred was the lowest among crossbreds. Feed intake (FI) of B crossbred was significantly higher compared to the other crossbreds at 20~24, 32~44 and 52~60 weeks of age. FI of D crossbred was significantly lower compared to other crossbreds after the age of 44 weeks (P<0.05). Average egg weight of B crossbred was significantly higher than the other crossbreds at the age of 24~60 weeks (P<0.05). Egg production ratio (%) of C crossbred was significantly higher compared to the other crossbreds for whole test periods (P<0.05). Hen-housed egg production number at 64 weeks of age for A, B, C and D crossbreds resulted in 241.4, 235.6, 232.3 and 227.0, respectively. Feed conversion ratio of A and C crossbreds was lower compared to the other crossbreds at the age of 20~24 weeks and C crossbred was the lowest among the crossbreds at the age of 60~64 weeks. These results provide the basic data which will be helpful to develope the new strains of commercial Korean Native Chickens.

• Korean Journal of Poultry Science
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• v.6 no.2
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• pp.75-81
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• 1979

This study was carried out to select superior dual purpose hens which could spread to poultry farming for subsidiary work and general farmhouse. Three hundred and fifty chicks of 7 kinds of 2-way crossbred from mating of Rhode Island Red, New Hampshire and Australorps were tested for dual purpose performance. The results obtained were as follows: 1. The average viability of brooding, rearing and laying Period hen were 92.3% 98.3% and 93.1% respectively. There was significant difference at 1% level among crossbreds for brooding viability, but other viabilitys were no significant difference. 2. The average body weight of 8 weeks was 854.41g, but there was no significant difference among crossbreds, respectively. Average body weight at 300 days, 500 days were 2507.15g, 2632.25g respectively, but there was significant difference at 1% level among crossbreds. 3. Sexual maturity of individual and 50% egg production were 173.7 days and 199.4 days, respectively. There was significant difference at 5% level among crossbreds. 4. The average hen day egg production was 65.3% and the highest was R.N crossbred (70.5%). There was significant difference at 5% level among crossbreds and average hen housed egg Production was 20.2 eggs and the highest was 220.4 eggs in R.A. crossbred. 5. The average egg weight was 57.36g and the highest was A.N crossbred (58.3g). Therc was no significant difference among crossbreds. 6. The average feed consumption per hen per day by stag. was 42.9g (brooding period), 83.7g (rearing period), 131.1g (laying period). Average feed requirement per 1kg. egg production was 3.79 and th. R.A. crossbred was superiority (3.42). 7. On the basis of the results of this study, the R.A and R.N crossbreds were best for superior dual commercial chicks under farming management conditions.

• 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.