• Korean Journal of Poultry Science
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• v.50 no.4
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• pp.213-229
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• 2023

This study aimed to investigate the effects of beak trimming and crossbreeding-combinations on the productive performance and stress response levels of Korean native chickens. The study divided 248 individuals from six crossbreeding-combinations into two groups: one underwent beak trimming, and the other did not. The survival rate, body weight, egg production rate, egg quality, feather damage score, HSP-70 gene expression level, H/L ratio, and intracellular DNA damage rate were measured and analyzed. The results showed that the beak-trimmed group had significantly higher survival rates and hen-housed egg production compared to the non-beak-trimmed group (P<0.05). Feather damage and DNA damage rates were significantly lower in the beak-trimmed group (P<0.05). On the other hand, there were no significant differences between the two groups in adult body weight, hen-day egg production, egg quality, HSP-70 gene expression level, and H/L ratio. Among the crossbreeding-combinations, there were significant differences in survival rate, body weight, feather damage score, egg quality, and DNA damage rate (P<0.05), while egg production rate, HSP-70 gene expression level, and H/L ratio showed no significant differences. There was an interaction between beak trimming and crossbreeding-combinations in some traits. In conclusion, beak trimming in Korean native chickens has a positive impact on productive performance, and in terms of stress response, beak trimming may not act as a stress factor or may even reduce stress after the growing period. Furthermore, there were differences in productive performance and stress response levels among crossbreeding-combinations, but the effects of beak trimming were similar across these combinations.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.11
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• pp.1536-1540
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• 2006

Crossbreeding effects for wool quality traits viz. greasy fleece weight (kg), staple length (cm), average fibre diameter (${\mu}$) and medulation percentage were estimated using the Dickerson's and Kinghorn's models. The data analyzed involved 15 genetic groups including Nali purebred, $F_1$'s of two and three breeds, $F_2$'s and reciprocal crossbred obtained from the crossing of Nali (N), Merino (M) and Corriedale (C) breeds during 1980-96. Nali and Corriedale breeds had non-significant negative additive genetic effects (Dickerson's model) on greasy fleece weight, while effects of Corriedale were negative for staple length only from both models. In general additive genetic effects of all three breeds were non-significant for all the wool traits except medulation percentage. Non significant heterotic and recombination effects (epistatic loss) were estimated from both models. However, the estimates of crossbreeding effects varied between the models both in magnitude as well as in direction barring few exceptions. Undesirable positive heterosis was found on medulation percentage for all types of combinations involving three breeds. Comparison of least squares means of various genetic groups revealed that both two breed and three breed crosses were superior to the Nali breed for all wool quality traits. Fibre diameter of MN crossbreds was significantly less than CN crossbreds. Results also indicated that as the inheritance of Nali breed in a cross is decreased, the medulation percentage decreases which is desirable. Inter se mating of crossbreds (two breed, three breed) has not resulted in a decline in the wool quality traits. These results indicate that the synthetic population derived from three breeds can be stabilized easily for wool traits as there may not be epistatic loss on subsequent inter se mating of crossbreds.

• 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.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.6
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• pp.777-782
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• 2002

Reciprocal effects among local breeds and additive and heterosis effects were estimated for total milk production per lactation (TLP), lactation length (LL) and daily milk yield (DMY). Procedures for an optimum crossbreeding system were examined by comparing various crossbred combinations. Three data sets were chosen from the total records collected from 1962 to 1997. Data set I with a total of 5,938 records composed of 9 breed groups for reciprocal crosses, data set II with a total of 6,064 records composed of 5 breed groups for additive and heterosis effects and data set III with a total of 10,319 records composed of 42 breed groups for optimum crossbreeding system were analyzed. The least squares ANOVA was used. The reciprocal crosses between Red Sindhi and the Bangladeshi Local showed significant difference. When the Red Sindhi was used as cow, the cross was superior to the opposite in terms of the three performance traits. The results showed that additive breed effects on both TLP and DMY were positive and highly significant between Bos indicus and Bos taurus, whereas the individual heterosis effects were not significant. In general, any local breeds were improved two to three times by crossing with the Friesian once or twice. However, the effect was reduced when the grading up with the Friesian was repeated more than twice. On the other hand, when the local breed was crossed with the other breeds such as Holstein and Jersey, the improvement of TLP was less. Crossing the F1 cows with the Friesian bull gave further improvement. Almost the same trends were found also for LL and DMY. The local breeds and their crosses are raised mainly for draft animals, then it is recommended that the crossbreds between the local cows and Friesian are used for dairy purposes and more than 75% Friesian blood is used for beef.

• Korean Journal of Poultry Science
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• v.48 no.3
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• pp.101-110
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• 2021

In this study, we performed a cross-combination test using offspring from two paternal and five maternal parent stock lines to produce a new synthetic breed of Korean native commercial chickens. The survival rate, body weight, feed intake, and feed efficiency were measured for 10 crosses, with 837 Hanhyup-3 chickens used as a control. Most chickens had brown-based feathers, and there was little difference in color phenotypes among combinations. The average survival rate of the combinations was 94.9%, which was significantly different from that of Hanhyup-3 at 75.3% (P<0.01). There was significant differences in body weight among the combinations at all weeks of age (P<0.01). At 10 weeks of age, the FHHY combination was the heaviest with 2,300 g, while the weight of Hanhyup-3 was 1,922 g. In addition, the weight difference between the male and female chickens was 458 g. As a result of regression analysis, the duration needed to reach 1.9 kg was about 61 days for the FHFY, FHHY, and HFFY combinations, and 70 days for Hanhyup-3, exhibiting a 9-day difference. The average feed conversion ratio of the combinations until 10 weeks was 2.42, which was significantly different from that of Hanhyup-3 at 2.97 (P<0.01). In conclusion, FHHY, FHFY, and HFFY were determined to be the best new breed combinations based on production capacity. When these combinations are used as new commercial breeds, they are expected to increase the average weight by 18% and improve feed efficiency by 19%, as compared to the existing Hanhyup-3 breed.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.1
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• pp.124-132
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• 2023

This study aimed to cross between Korean and Japanese pure lines of Neopyropia strains to establish cross breeding technology and identify a superior variety that harbors the strength of both parents. Four crossing combinations were tried using three methods, resulting in 1,476 single conchocelis colonies. The three co-dominant Cleaved Amplified Polymorphic Sequence (CAPS) markers (EF-1α/Mse I, TOP2/Mse I, car A/ApaL I) were used to distinguish heterozygotic sporophytes and their maternal lines obtained from the inter and intraspecific cross-fertilization within the wild type of Neopyropia strains. Of the 1,476 colonies, 26.9% (218) were heterozygotes obtained from the nuclear CAPS markers. Their maternal line was clearly confirmed using organelle CAPS marker and chimeric thallus was obtained from crossing experiment of Japanese N. yezoensis (♀) and Korean N. yezoensis (♂). The use of CAPS markers improved the efficiency of crossbreeding by quickly screening heterozygotes and maternal lines in the conchocelis phase, which otherwise required pigmentation mutants as genetic markers.

• Journal of Life Science
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• v.30 no.3
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• pp.239-249
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• 2020

Persimmon flowers are fruit-bearing female, pollen-bearing male, or hermaphrodite, containing both a pistil and a stamen. Using prominent PCNA persimmons as male parents is very important for breeding programs, as the selection procedure for new cultivars bearing male flowers requires a long time and a large field in a traditional crossbreeding method. To improve breeding efficiency through early selection of male flower-bearing plants at the seedling stage, analysis was performed on 88 major cultivars whose gender expressions are known, using two male flower selection markers recommended by Akagi et al. The OGI locus marker and DISx-AF4S marker results showed that 83 and 72 cultivars, respectively, matched in terms of gender expression and marker analysis. For the OGI locus marker, 890 plants were selected from 2,509 seedlings obtained from crossbreeding with the mother plant "Migamjosang," which was the breeding cultivar. Comparing the gender expression of the flowers and the marker with 1,186 crossbred seedlings, excluding the unfertilized and dead plants, inconsistencies were found in 401 plants (33.8%). For the DISx-AF4S marker, 636 plants were selected from 889 seedlings obtained from 12 cross-combinations. The results of the sex expression and marker analysis were compared to 379 plants, excluding the unfertilized and dead plants, and inconsistencies were found in 247 plants (65.2%). These results indicate that the examined DISx-AF4S and OGI locus markers would not be suitable for utilization in the breeding field.