• Asian-Australasian Journal of Animal Sciences
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• v.30 no.8
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• pp.1074-1080
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• 2017

Objective: The growth, carcass and retail cut yield records on 1,428 Hanwoo steers obtained through progeny testing were analyzed in this study, and their heritability and genetic relationships among the traits were estimated using animal models. Methods: Two different models were compared in this study. Each model was fitted for different fixed class effects, date of slaughter for carcass traits and batch of progeny test live measurement traits, and a choice of covariates (carcass weight in Model 1 or backfat thickness in Model 2) for carcass traits. Results: The differences in body composition among individuals were deemed being unaffected by their age at slaughter, except for carcass weight and backfat thickness. Heritability estimates of body size measurements were 0.21 to 0.36. Heritability estimates of retail cut percentage were high (0.56 from Model 1 and 0.47 from Model 2). And the heritability estimates for loin muscle percentage were 0.36 from Model 1 and 0.42 from Model 2, which were high enough to consider direct selection on carcass cutability traits as effective. The genetic correlations between body size measurements and retail cut ratio (RCR) were close to zero. But, some negative genetic correlations were found with chest girths measured at yearling (Model 1) or at 24 months of age or with chest widths. Loin muscle ratio (LMR) was genetically negatively correlated with body weights or body size measurements, in general in Model 1. These relationships were low close to zero but positive in Model 2. Phenotypic correlation between cutability traits (RCR, LMR) and live body size measurements were moderate and negative in Model 1 while those in Model 2 were all close to zero. Conclusion: Therefore, the body weights or linear body measurements at an earlier age may not be the most desirable selection traits for exploitation of correlated responses to improve loin muscle or lean meat yield.

• Proceedings of the Botanical Society of Korea Conference
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• 1995.07a
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• pp.57-86
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• 1995

Molecular mapping of plant genomes has progressed rapidly since Bostein et al.(1980) introduced the idea of constructing linkage maps of human genome based on restriction fragment length polymorphism (RFLP) markers. In recent years, the development of protein and DNA markers has stimulated interest for the new approaches to plant improvement. While classical maps based on morphological mutant markers have provided important insights into the plant genetics and cytology, the molecular maps based on molecular markers have a number of inherent advatages over classical genetic maps for the applications in genetic studies and/or breeding schemes. Isozymes and DNA markers are numerous, discrete, non-deleterious, codominant, and almost entirely free of environmental and epistatic interactions. For these reasons, they are widely used in constructing detailed linkage maps in a number of plant species. Plant breeders improve crops by selecting plants with desirable phenotypes. However a plant's phenotyes is often under genetic control, positioning at different "quantitative trait loci" (QTLs) together with environmental effects. Molecular maps provide a possible way to determine the effect of the individual gene that combines to produce a quantitative trait because the segregation of a large number of markers can be followed in a single genetic cross. Using market-assisted selection, plants that contain several favorable genes for the trait and do not contain unfavourable segments can be obtained during early breeding processes. Providing molecular maps are available, valuable data relevant to the taxonomic relationships and chromosome evolution can be accumulated by comparative mapping and also the structural relationships between linkage map and physical map can be identified by cDNA sequencing. After constructing high density maps, it will be possible to clone genes, whose products are unknown, such as semidwarf and disease resistance genes. However, much attention has to be paid to level-up the basic knowledge of genetics, physiology, biochemistry, plant pathology, entomology, microbiology, and so on. It must also be kept in mind that scientists in various fields will have to make another take off by intensive cooperation together for early integration and utilization of these newly emerging high-techs in practical breeding. breeding.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.3
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• pp.328-333
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• 2015

A genome wide association study was conducted using estimated breeding value (EBV) for milk production traits from 1st to 4th lactation. Significant single nucleotide polymorphism (SNP) markers were selected for each trait and the differences were compared by lactation. DNA samples were taken from 456 animals with EBV which are Holstein proven bulls whose semen is being sold or the daughters of old proven bulls whose semen is no longer being sold in Korea. High density genome wide SNP genotype was investigated and the significance of markers associated with traits was tested using the breeding value estimated by a multiple lactation model as a dependent variant. As the result of significance comparisons by lactations, several differences were found between the first lactation and subsequent lactations (from second to 4th lactation). A similar trend was noted in mean deviation and correlation of the estimated effects by lactation. Since there was a difference in the genes associated with EBV for each trait between first and subsequent lactations, a multi-lactation model in which lactation is considered as a different trait is genetically useful. Also, significant markers in all lactations and common markers for different traits were detected, which can be used as markers for quantitative trait loci exploration and marker assisted selection in milk production traits.

• Journal of Animal Science and Technology
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• v.53 no.1
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• pp.1-6
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• 2011

This simulation study was performed to investigate the accuracy of the estimated breeding value by using genomic information (GEBV) by way of Bayesian framework. Genomic information by way of single nucleotide polymorphism (SNP) from a chromosome with length of 100cM were simulated with different marker distance (0.1cM, 0.5cM), heritabilities (0.1, 0.5) and half sibs families (20 heads, 4 heads). For generating the simulated population in which animals were inferred to genomic polymorphism, we assumed that the number of quantitative trait loci (QTL) were equal with the number of no effect markers. The positions of markers and QTLs were located with even and scatter distances, respectively. The accuracies of estimated breeding values by way of indicating correlations between true and estimated breeding values were compared on several cases of marker distances, heritabilities and family sizes. The accuracies of breeding values on animals only having genomic information were 0.87 and 0.81 in marker distances of 0.1cM and 0.5cM, respectively. These accuracies were shown to be influenced by heritabilities (0.87 at $h^2$ =0.10, 0.94 at $h^2$ =0.50). According to half sibs' family size, these accuracies were 0.87 and 0.84 in family size of 20 and 4, respectively. As half sibs family size is high, accuracy of breeding appeared high. Based on the results of this study it is concluded that the amount of marker information, heritability and family size would influence the accuracy of the estimated breeding values in genomic selection methodology for animal breeding.

• Animal Bioscience
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• v.34 no.7
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• pp.1193-1201
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• 2021

Objective: According to market demand, meat duck breeding mainly includes 2 breeding directions: lean Pekin duck (LPD) and fat Pekin duck (FPD). The aim of the present study was to compare carcass and meat quality traits between 2 strains, and to provide basic data for guidelines of processing and meat quality improvement. Methods: A total of 62 female Pekin ducks (32 LPDs and 30 FPDs) were slaughtered at the age of 42 days. The live body weight and carcass traits were measured and calculated. Physical properties of breast muscle were determined by texture analyzer and muscle fibers were measured by paraffin sections. The content of inosine monophosphate (IMP), intramuscular fat (IMF) and fatty acids composition were measured by high-performance liquid chromatography, Soxhlet extraction method and automated gas chromatography respectively. Results: The results showed that the bodyweight of LPDs was higher than that of FPDs. FPDs were significantly higher than LPDs in subcutaneous fat thickness, subcutaneous fat weight, subcutaneous fat percentage, abdominal fat percentage and abdominal fat shear force (p<0.01). LPDs were significantly higher than FPDs in breast muscle thickness, breast muscle weight, breast muscle rate and breast muscle shear force (p<0.01). The muscle fiber average area and fiber diameter of LPDs were significantly higher than those of FPDs (p<0.01). The muscle fiber density of LPDs was significantly lower than that of FPDs (p<0.01). The IMF of LPDs in the breast muscle was significantly higher than that in the FPDs (p<0.01). There was no significant difference between the 2 strains in IMP content (p>0.05). The polyunsaturated fatty acid content of LPDs was significantly higher than that of FPDs (p<0.01), and FPDs had higher saturated fatty acid and monounsaturated fatty acid levels (p<0.05). Conclusion: Long-term breeding work resulted in vast differences between the two strains Pekin ducks. This study provides a reference for differences between LPD and FPD that manifest as a result of long-term selection.

• Proceedings of the Korean Society of Applied Entomolohy Conference
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• 2001.11a
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• pp.60-60
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• 2001

• Journal of Forest and Environmental Science
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• v.11 no.1
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• pp.81-101
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• 1995

Random amplified polymorphic DNA (RAPD) technology, a recent approach in molecular genetics, is much usable to select the elite trees and to maximize the genetic gain in forest tree breeding program, providing a clue to determine the genetic marker-trait correlation. This review intorduces research on bark thickness and breeding strategy in Pinus elliottii, Pinus caribaea and their hybrid by Queensland Forest Service and ForBio Research Pty Ltd, University of Queensland, which employ RAPD technology. Genetic linkage map of $F_1$ hybrids includes 186 RAPD markers and 16 linkage groups (1641 cM long in total) and 6 quantitative trait loci are located putatively for bark thickness. Following recent research results and experiences in pine breeding programs, the forseeable stages in the application and development are proposed for marker assisted selectin; stage 1-determination of species specific markers for genes controlling traits of commercial interest, and stage 2-determination of marker-allele association for specific allelic variants within pure species. As pines inherit their megagametophytes from the seed parent and zygotic embryos from both male and female parents, the determination of marker-trait correlation is possible even in embryo stage, eventually making ways for the early selection of elite individuals.

• Asian-Australasian Journal of Animal Sciences
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• v.10 no.6
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• pp.567-570
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• 1997

A multiple trait animal model having milk yield and lactation length was used to estimate genetic parameters using data from four institutional herds and four field recording centers. Response to selection for milk yield alone and in combination with lactation length was estimated by using principles of genetic theory. Lactation records (n = 2,353) adjusted for age at calving to 60 months were utilized. Milk yield was 17% heritable with repeatability of 0.44. Lactation length had a low heritability of 0.06 with repeatability of 0.16. Genetic correlation between the two traits was 0.70. Selection response in milk yield can be improved slightly (103.8 vs 102.8 kg) when information on covariance with lactation length is used together with the information on milk yield.

• International Journal of Industrial Entomology and Biomaterials
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• v.4 no.2
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• pp.121-126
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• 2002

Breeding programme was initiated during November, 1995 with the main objective to breed productive multivoltine breeds/ hybrids with suitable genetic constitution to suit the fluctuating tropical climate prevailed in India. Two multivoltine breeds viz., BL-24 and BL-27 selected were as breeding resource materials from the silkworm germplasm maintained at Central Sericul-tural Research and Training Institute, Mysore. By adopting hybridization, backcrossing inbreeding and selection, a new multivoltine breed namely BL-67. This breed spins light greenish yellow cocoons and cocoon shape is oval with medium to coarse grains. The evolved breed was crossed with five tropical bivoltine breeds viz., NB4D2, CSR2, CSR5, CSR18 and CSR101 to study the combining ability, and identified a superior hybrid, BL67 ${\times}$ CSR101, named as CAUVERY, The hybrid is characterized by high pupation rate (>95%), high shell weight (> 35 cg), high cocoon shell ratio (> 20%), longer filament length (> 900 m) and high neatness (93) with a renditta of 6.5 producing 2A-3A grade silk. The hybrid is selected for Race Autho-rization test of Central Silk Board.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2020.12a
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• pp.59-59
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• 2020

Salix gracilistyla has a characteristic of fast growth especially in the river side or infertile soil, showing a lot of lateral branches and a strong root system among the Salix. spp. On the basis of results observed, we provide several growth characteristics of S. gracilistyla among some selected provenances. In two-year results, root collar diameter ranged from 33.5 mm to 56.7 mm. Taeback showed the lowest value, and Jeongseon and Hoengseong were higher than the other areas in the traits above. Height growth was the lowest in Samcheok and the highest in Wonju. To examine growth and development of lateral branches is important because S. gracilistyla has a lot of lateral branches which account for high biomass production. Length of lateral branch showed high variation, in which the highest number was observed in Yeongwol and the lowest in Samcheok. Many lateral branches were shown in Wonju. Preliminary study on biomass resources evaluation, we analyzed correlation between volume and length, and volume and root diameter. High correlation was observed between root diameter and plant volume. And we compared the observed volume with the caculated volume by regression formula. To evaluate Salix species as biomass resources, it is needed to survey growth characteristics continuously and adopt selection of individuals or families of high biomass and caloric values by reliable data. In addition, Salix spp. can be also applicable to selection breeding regime because of feasible propagation and fast growth.