• KOREAN JOURNAL OF CROP SCIENCE
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• v.35 no.6
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• pp.532-538
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• 1990

This experiment was carried out to establish the efficiency of crop breeding on comparison of combination methods of single, 3-way, and double crosses and combination order of 4 winter wheat which were different in origin, source, and plant types, On comparison of 4 crossing modes, there appeared the earliest heading and the highest grain yield in double cross, and decreased in 3-way. single crosses. and parents in order, There showed the significant mean squares of GCA and SCA in 4${\times}$4 diallel analysis for grain yield and yield components. Grumil and Bezostaya 1 exhibited highest GCA effect of grain yield which appeared the actual highest grain yield. There appeared the highest SCA-effect in F$_1$ (Eunpamil/Bezostaya 1) showing 4.22. Of the 3 double crosses there exhibited the highest grain yield in F$_1$ (Grumil/Eunpamil/ /Lanota/Bezostaya 1). Two single crosses for this double cross ---F$_1$ (Grumil/Eunpamil) and F$_1$ (Lancota/Bezostaya 1) --- do not revealed directly for this yield, but combined each other by chromosome switch as combination of F$_1$ (Grumil/Lancota), F$_1$(Grumil/Bezostaya 1), F$_1$(Eunpamil/Lancota) and F$_1$(Eunpamil/Bezostaya 1) which appeared the higher grain yields and SCA-effects. Of the six 3-way crosses. F$_1$ (Lancota/Bezostaya 1/ /Eunpamil) expressed the highest grain yield. Its combinations were F$_1$ (Lancota/Eunpamil) and F$_1$ (Bezostaya 1/Eunpamil) combined by chromosome switch, which its grain yield and SCA-effect were higher.

• Korean Journal of Animal Reproduction
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• v.24 no.2
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• pp.209-216
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• 2000

This study was carried out to investigate the effects of breed, age of boar, season, parity and mating system on boar semen characteristics and fertilizing capacity. A total of 4181 sows and 199 boars of Durocs (D), Landraces (L), and Yorkshires (Y) were used for this experiment at Darby Artificicial Insemination Center from 1996 through 1999. Semen volume per ejaculate was largest in Landrace (266.8 $m\ell$), followed by Yorkshire, and was smallest in Duroc. Sperm motility did not show significant differences among the above breeds. Sperm concentration was lowest in Landrace (4.7$\times$10$^{9}$ sperm/$m\ell$) and was highest in Duroc (5.7$\times$10$^{9}$ sperm/$m\ell$). Semen volume per ejaculate according to the age of boars was largest at the age of 2 years, followed by the age of 4 and 3 years, and was smallest at the age of I year. Semen volume per ejaculate according to the season in boars was largest in winter (228.6 $m\ell$), followed by autumn and summer, and was smallest in spring. Sperm concentration was highest in spring (5.9$\times$10$^{9}$ sperm/$m\ell$), followed by summer and winter, and was lowest in autumn. The average litter weight at birth did not show any differences according to the mating type. But the number of pigs born alive per litter was largest (9.5 pigs) in the natural mating ＋ artificial insemination group, followed by the artificial insemination group (9.2 pigs), and was smallest (8.9 pigs) in the natural mating group (P＜0.01). The average litter weight at birth and number of pigs born alive per litter did not show any differences between the natural mating and artificial insemination. The L (♀)$\times$Y (♂) and L (♀)$\times$L (♂) matings show $\varepsilon$ d higher average litter weight at birth and number of pigs born alive per litter than the Y (♀) $\times$ Y (♂) and Y (♀) $\times$ L (♂) matings. The pigs in the 2~6th parities had higher average litter weight at birth and number of pigs born alive per litter than those in the 1 st and 7~9th parities.

• Korean Journal of Poultry Science
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• v.50 no.4
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• pp.203-212
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• 2023

This study conducted a diallel-crossbreeding test using four Korean native chicken parent stock lines (YC, YD, CK, and CF) to develop a native commercial layer with high egg-laying performance. A total of 312 chickens in six combinations were examined for various traits, including livability, body weight, age at first egg-laying, hen-day, and hen-housed egg production, egg weight, and egg quality, from hatching to 60 weeks of age. The results showed that the average survival rate was 77.1±18.8% with the YDYC combination having the highest survival rate along with excellent specific combining ability. The YDYC combination exhibited significantly higher body weight compared to the other combinations (P<0.01). The average age at first egg-laying was 121.3±2.5 days, with no significant difference between the combinations. The average hen-day egg production was 74.0±6.4%, and the hen-housed egg production was 181.4±33.8 eggs with the YDCF and YCCK combinations demonstrating the highest laying performance, while the YDYC and CKCF combinations had the lowest (P<0.05). Laying performance was more influenced by specific combining ability than general combining ability. The eggs from the YDYC combination were significantly lighter and had the darkest shell color (P<0.01), whereas the YDCF combination exhibited the thickest eggshells. There was no difference in internal egg quality among combinations, except the YDCF combination had the darkest yolk color. Overall, we concluded that the YCCK combination, characterized by high laying performance and livability, and the YDCF combination with high laying performance and good egg quality are the most desirable combinations for Korean native commercial layers.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.6
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• pp.424-428
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• 2003

This study was conducted to find out the optimum cultural method for hybrid seed production of Chalok 2. Higher seed yield was obtained when KW3 was used as a seed parent (female). KW7 was shown Higher barren stalk occurrence which caused significant seed yield reduction when it was used as a seed parent (female). The ratio of female (KW3) to male (KW7) rows with 4 to 1 had higher seed yield than that of 2:1 or 3:1. In case of using KW3 toy a seed parent, KW3 was susceptible to stem and ear rotting disease. The 35th day after silking was optimal period to harvest due to higher 100-grain weight, lower rotten grain, and higher germination rate.

• Journal of Animal Science and Technology
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• v.49 no.2
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• pp.171-176
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• 2007

A total of 4,627 records on pre-weaning growth traits, birth weight(BW), weaning weight(WW) and pre-weaning daily gain(ADG) of Hanwoo’s born form 1970 to 2005 were collected from Hanwoo Experiment Station, National Livestock Research Institute. Variance components and heritabilities of BW, WW and ADG were estimated with two models; Model 1 included only direct genetic effect while Mode1 2 included direct genetic, maternal genetic and permanent environmental effects. Direct herit- ability estimates of BW, WW and ADG estimated by model 1 were 0.34, 0.26 and 0.20, respectively. In model 2, direct heritability and maternal genetic heritability estimates were 0.14 and 0.06 for BW, 0.07 and 0.04 for WW and 0.05 and 0.04 for ADG. Estimates of genetic correlation between direct and maternal effect for BW, WW and ADG were 0.58, 0.75 and 0.61, respectively. Genetic correlation coefficients between BW and WW, between BW and ADG, and between WW and ADG were 0.76, 0.62 and 0.99, respectively.

• Korean Journal of Breeding Science
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• v.41 no.4
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• pp.595-598
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• 2009

A new yellow gerbera (Gerbera hybrida Hort.) cultivar "Golden Time" was developed from a cross between '99-ga-2' and '99-na-7-6', followed by seedling and line selections at the Flower Research Institute, Gyeongnam Agricultural Research and Extension Services (ARES) in 2007. Detailed characteristics of the new cultivar were evaluated from 2004 to 2007. "Golden Time" has semi-double type large flowers in a good harmony with yellow (RHS, 17-B) ray floret and brown center. It has good, stable flower shape and strong peduncles, and its vase life was 12.3 days. The average flower yield of "Golden Time" was about 49.5 stems per plant/year in greenhouse trails during 2004 and 2007. This cultivar was registered to the Korea Seed and Variety Service (KSVS) for commercialization in 2009. Year-round production of this cultivar is possible in the greenhouse condition throughout the Korean climate.

• FLOWER RESEARCH JOURNAL
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• v.16 no.2
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• pp.124-127
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• 2008

A new orange-colored, cut flower gerbera (Gerbera hybrida Hort.) cultivar 'Sweety' was developed from a cross between 'Grandeur' and 'Songsongee', followed by selections of seedlings and lines at the Flower Breeding Research Institute, Gyeongnam Agricultural Research and Extension Services (ARES) from 1999 to 2004. Three time evaluations were conducted from 2003 for the detailed characteristics of the new cultivar. 'Sweety' has semi-double type mini- or medium-sized flowers in good harmony with orange(RHS, 38-A) ray florets and a green center. It has good, stable flower shape and strong peduncle, and its vase life was 10.4 days. The average flower yield was about 51.0 stems per plant/year in greenhouse trails during 2003 and 2004. This cultivar was registered to the Korea Seed and Variety Service for commercialization in 2006. Year-round production of this cultivar is possible in the greenhouse condition in Korean climate.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.1
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• pp.45-52
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• 1996

This study was conducted to know how cold tolerance of rice is inherited. Several crosses were made between cold tolerant and susceptible varieties, and their progenies were evaluated for days to heading, spikelet number per panicle and spikelet fertility under both cold water and natural conditions. In F$_1$ and F$_2$ generations, earlier heading, more number of spikelet per panicle and higher spikelet fertility under the cold condition were dominance, and less delay or reduction in heading days and spikelets per panicle by cold treatment were over dominance or partial dominance, while less reduction in spikelet fertility by cold-water irrigation was complete dominance. Heritability in most characters by cold treatment was high and there was less difference of heritabilities in heading days and spikelets per panicle between cold treatment and natural conditions, while there was much difference of heritability in spikelet fertility between two conditions. Heterosis in spikelet fertility was considerably high, while those in heading days and spikelets per panicle were relatively low. Heterosis in remote crosses was especially larger under the cold-water treatment condition compare with that under natural condition.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.29 no.1
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• pp.1-10
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• 1984

The main objective of this experiment was to investigate the selection efficiency for clear rice by the application of the wx-carrier technique in rice. Twelve semi-dwarf waxy lines were bred through backcrosses to the two recurrent semi-dwarf parents, IR667 and IR1317, utilizing six different waxy cultivars as waxy donor parent. These waxy lines were crossed to three clear non-waxy varieties, IR24, Suweon 287 and Suweon294. Their F$_3$ seeds were separated into waxy and non-waxy and the clearness of non-waxy grains were counted. The results are summarized as follows: l. Mean clearness per plant for twelve waxy lines ranged from 3.7% to 78.9% at the 35 days after heading. It was higher in the lines which utilized IR 1317 as recurrent parent and it was lower in the lines which utilized IR667 as recurrent parent. Mean clearness per plant for recurrent parent, IRl317 and IR667 were 47.6% and 5.6% respectively. The clear non-waxy parents; Suweon287, IR24 and Suweon294 showed 83.7% 80.5% and 73.5% clearness respectively. 2. Mean clearness of F$_3$ seeds of the crosses between different waxy parents and IR24, Suweon 294 and Suweon 287 ranged 16.7-73.9%, 21.9-42.9% and 10.6-26.9%, respectively. IR24 crosses showed the highest mean clearness. 3. Highly positive correlation was found between the clearness of F$_3$ seeds of Suweon 287 crosses and those of Suweon294. 4. Significant differences were observed in mean clearness of F$_3$ seeds of the crosses between the different waxy lines, which was bred through the same number of backcrosses to the same recurrent parent, and a clear non-waxy parent. Crosses of IR1317 recurrent parent showed higher mean clearness than those of IR667 recurrent parent. 5. In some crosses, clearness was higher in homo-non-waxy than in hetero-non-waxy, but, in other crosses it was higher in hetero-non-waxy. Thus no distinct pattern in the segregation of clearness was observed along the homo-non-waxy or hetero-non-waxy. 6. From the results it was concluded that, the selection efficiency for the clear rice can be improved by choosing the proper waxy parent, as well as proper recurrent parent under the wx-carrier technique.

• Korean Journal of Breeding Science
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• v.42 no.4
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• pp.374-380
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• 2010

In order to select excellent cross parents in strawberry breeding, 11 varieties were self-pollinated and tested their progenies. Among the 11 varieties, 'Akihime', 'Maehyang' and 'Seolhyang' showed superior in plant vigor, disease resistance and yield. Combining ability was tested using 15 progenies obtained from crosses between 3 selected varieties as seed parents and 5 varieties as pollen parents. Plant vigor was the strongest when 'Akihime' was used as a seed parent while ripening time tended to the fastest when 'Seolhyang' as a seed parent. Average fruit weight of the crosses 'Seolhyang' ${\times}$ 'Tochiotome', 'Seolhyang' ${\times}$ 'Geumhyang', 'Seolhyang' ${\times}$ 'Wongyo 3111' and 'Akihime' ${\times}$ 'Wongyo 3111' were above 18 g for marketable fruits. Fruit hardness was superior at crosses of 'Maehyang' as a seed parents to other crosses combinations, especially 'Maehyang' ${\times}$ 'Tochiotome'. Soluble solid contents (SSC) was not significantly different among cross combinations. The best cross combination for marketable yield was 'Akihime' ${\times}$ 'Wongyo 3111', followed by 'Seolhyang' ${\times}$ 'Geumhyang', 'Maehyang' ${\times}$ 'Geumhyang', 'Akihime' ${\times}$ 'Tochiotome', in order.