• Animal Bioscience
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• v.35 no.11
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• pp.1635-1648
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• 2022

Thermal stress due to extreme changes in the thermal environment is a critical issue in cattle production. Many previous findings have shown a decrease in feed intake, milk yield, growth rate, and reproductive efficiency of cattle when subjected to thermal stress. Therefore, selecting thermo-tolerant animals is the primary goal of the efficiency of breeding programs to reduce those adverse impacts. The recent advances in molecular genetics have provided significant breeding advantages that allow the identification of molecular markers in both beef and dairy cattle breeding, including marker-assisted selection (MAS) as a tool in selecting superior thermo-tolerant animals. Single-nucleotide polymorphisms (SNPs), which can be detected by DNA sequencing, are desirable DNA markers for MAS due to their abundance in the genome's coding and non-coding regions. Many SNPs in some genes (e.g., HSP70, HSP90, HSF1, EIF2AK4, HSBP1, HSPB8, HSPB7, MYO1A, and ATP1A1) in various breeds of cattle have been analyzed to play key roles in many cellular activities during thermal stress and protecting cells against stress, making them potential candidate genes for molecular markers of thermotolerance. This review highlights the associations of SNPs within these genes with thermotolerance traits (e.g., blood biochemistry and physiological responses) and suggests their potential use as MAS in thermotolerant cattle breeding.

• Molecules and Cells
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• v.25 no.1
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• pp.20-29
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• 2008

Cytoplasmic male sterility (CMS), one of the most important traits in crop breeding, has been used for commercial seed production by $F_1$ hybrid cultivars of pepper (Capsicum annuum L.). To develop reliable molecular markers for allelic selection of the Restorer-of-fertility (Rf) gene, which is known to be a major determinant of pollen fertility restoration in peppers, a sequence of approximately 10 kb flanking an RAPD fragment closely linked to the Rf locus was obtained by genome walking. A homology search revealed that this sequence contained an LTR retrotransposon and a non-LTR LINE-like retrotransposon. Sequencing of this Rf-linked region to search for polymorphisms between a dominant and recessive allele revealed 98% nucleotide sequence identity between them. A third polymorphic haplotype of the Rf-linked sequence, which has 94-96% nucleotide sequence identity with the two previously isolated haplotypes, was identified among a large number of breeding lines. Utilizing polymorphic sequences in the haplotypes, PCR markers were developed for selection of particular haplotypes and used to examine the distribution of the haplotypes in diverse breeding lines, cultivars, and C. annuum germplasms. Surprisingly, the third haplotype was the predominant type in C. annuum germplasms, while its frequency in $F_1$ hybrid cultivars was relatively low. Meanwhile, analysis of breeding lines whose Rf allele genotypes and male-sterility phenotypes were already known revealed that the third haplotype was mainly present in exotic breeding lines that cause unstable male-sterility when combined with sterile cytoplasms.

• International Journal of Industrial Entomology and Biomaterials
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• v.13 no.2
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• pp.85-95
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• 2006

Seveval Chinese and Japanese varieties with good characters were used in the breeding. After 5 years (15 generations), a pair of robust and high quality silkworm variety with NPV resistance was bred by means of a combination of crossing and pedigree selection complemented by the selection of NPV resistance. The variety was identified jointly nationwide in 2003 and 2004, and appraised by National Mulberry and Silkworm Appraising Committee. Results are as follows: its cocooning rate is over 93%, shell rate 23-25%, filament length 1200-1300 meters, reelability 75-88%, Length of non-broken cocoon filament 900-1100 meters, raw silk rate 17-19%, neatness 95-97 points, and cocoon crop, cocoon shell weight and raw silk weight per 10000 larvae is higher than those of the control variety by 7-10%, 14-19% and 14-18%, respectively. The variety is not only robust, resistant to high temperature and NPV, easy to rear, uniform in hatching, molting and maturing, but also lays more eggs, and its fecundity is high. It is suitable to rear in the Yangtze River Basin, the Yellow River basin and the Pearl River basin of China.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.9
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• pp.1387-1392
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• 2018

Objective: In a nucleus breeding scheme, the sire of dam's pathway plays an important role in producing genetic improvement. Selection proportion is the key parameter for predicting selection intensity, through truncating the normal distribution. Semen sexing using flow cytometry reduces the number of vials of sperm that can be obtained from a proved bull. In addition, a lower fertility of this kind of sperm is expected because of the lower sperm dosage in sex sorted semen. Both of these factors could affect the selection proportion in the sire of dam's pathway ($p_{SD}$). Methods: In the current study, through a deterministic simulation, effect of utilizing sex sorted semen on selection ($p_{SD}$) was investigated in three different strategies including 1: continuous use of sex sorted semen in heifers (CS), 2: the use of sex sorted semen for the first two (S2) and 3: the first (S1) inseminations followed by conventional semen. Results: Results indicated that the use of sex sorted semen has a negative impact on the sire of dams (SD) pathway due to increase in selection proportion. Consequently selection intensity was decreased by 10.24 to 20.57, 6.38 to 8.87 and 3.76 to 6.25 percent in the CS, S2, and S1 strategies, respectively. Conclusion: Considering the low effect of sexed semen on genetic improvement in dam pathways, it is necessary to consider the joint effect of using sex sorted semen on the sire and dams pathway to estimate about the real effect of sexed semen on genetic improvement in a nucleus breeding scheme.

• Korean Journal of Agricultural Science
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• v.48 no.4
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• pp.681-691
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• 2021

The estimated breeding value (EBV) and accuracy of Hanwoo steer (Korean cattle) is an indicator that can predict the slaughter time in the future and carcass performance outcomes. Recently, studies using pedigrees and genotypes are being actively conducted to improve the accuracy of the EBV. In this study, the pedigree and genotype of 46 steers obtained from livestock farm A in Gyeongnam were used for a pedigree best linear unbiased prediction (PBLUP) and a genomic best linear unbiased prediction (GBLUP) to estimate and analyze the breeding value and accuracy of the carcass weight (CWT), eye muscle area (EMA), back-fat thickness (BFT), and marbling score (MS). PBLUP estimated the EBV and accuracy by constructing a numeric relationship matrix (NRM) from the 46 steers and reference population I (545,483 heads) with the pedigree and phenotype. GBLUP estimated genomic EBV (GEBV) and accuracy by constructing a genomic relationship matrix (GRM) from the 46 steers and reference population II (16,972 heads) with the genotype and phenotype. As a result, in the order of CWT, EMA, BFT, and MS, the accuracy levels of PBLUP were 0.531, 0.519, 0.524 and 0.530, while the accuracy outcomes of GBLUP were 0.799, 0.779, 0.768, and 0.810. The accuracy estimated by GBLUP was 50.1 - 53.1% higher than that estimated by PBLUP. GEBV estimated with the genotype is expected to show higher accuracy than the EBV calculated using only the pedigree and is thus expected to be used as basic data for genomic selection in the future.

• Korean Journal of Plant Resources
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• v.32 no.3
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• pp.244-253
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• 2019

In crop breeding program, information about genetic dissimilarity on breeding resources is very important to corroborate genealogical relationships and to predict the most heterozygotic hybrid combinations and inbred breeding. This study aimed to evaluate the genetic variation in Kenyan sunflower breeding lines based on simple sequence repeat (SSR). A total of 83 alleles were detected at 32 SSR loci. The allele number per locus ranged from 2 to 7 with an average of 2.7 alleles per locus detected from the 24 sunflower accessions and the average value of polymorphic information contents (PIC) were 0.384. A cluster analysis based on the genetic similarity coefficients was conducted and the 24 sunflower breeding resources were classified into three groups. The principal coordinates (PCoA) revealed 34% and 13.38% respectively, and 47.38% of total variation. It was found that the genetic diversity within the Kenyan sunflower breeding resources was narrower than that in other sunflower germplasm resources, suggesting the importance and feasibility of introducing elite genotypes from different origins for selection of breeding lines with broader genetic base in Kenyan sunflower breeding program.

• Current Research on Agriculture and Life Sciences
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• v.31 no.2
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• pp.75-82
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• 2013

Haploids are plants with a gametophytic number of chromosomes in their sporophytes. Androgenesis occurs from asymmetric division of pollen grains into generative cells and vegetative cells, followed by re-entry of the vegetative cell during S-phase, which causes microspores progress into G2/M transition in culture. One of the most interesting features of haploids is the possibility to produce doubled haploid (DH) individuals. Doubled haploidy is extremely useful to plant breeders because it enables shortened breeding periods and efficiency in selection of useful recessive agronomic traits. Doubled-haploid technology is not only applicable to breeding, but also to transformation programs of desired genes. In addition to practical breeding programs, DH lines provide useful materials of fundamental genetics including exploitation of QTLs and genes conferred with various agronomic traits by establishing DH populations. This paper provides historical overviews on androgenesis and describes several mechanisms associated with pollen embryogenesis, including mode of actions in pollen embryogenesis, mechanisms of chromosome doubling and factors affecting androgenesis. We also discuss recent progress in application of haploids to breeding, genes associated with in vitro response and drawbacks to anther culture for application of doubled haploids in crop breeding.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.25 no.1
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• pp.39-46
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• 1980

A male sterile facilitated recurrent selection population was developed by the barley breeding team of Yeongnam Crop Experiment Station. To breed this population, three composite cross populations and a composite population of breeding lines in our country were used as the materials. This population was developed in order to breed early maturing, wet-soil tolerant and high yielding barley varieties, adapted for double cropping with rice in southern part of Korea. The population was named by RSPYB#l which means Recurrent Selection Population No.1. of Yeongnam Barley.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.2
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• pp.180-186
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• 1994

Lipoxygenase activity of soybean seeds of approximately 507 genotypes as well as its inheritance and selection efficiency in early breeding generation was measured in the Department of Agronomy, Seoul National University to facilitate breeding for low lipoxygenase activity of soybean. Average seed lipoxygenase activity of 507 cultivars and strains was 350 unit (unit: $\Delta$0.01 /min. /mg at 234nm) and ranged from 50 to 670 unit. There was no difference in mean lipoxygenase activity according to apparent seed characters such as seed coat and embryo color. But early mature soybean genotypes had fairly low lipoxygenase activity. Lipoxygenase activity was inherited quantitatively, in which additive effect was greater than dominant one and proportion of gene with positive effects was similar to that with negative ones. Estimated narrow- and broad-sense heritabilities were 0.78 and 0.86 for lipoxygenase activity, respectively. Heritability measured from selection in early breeding lines for high or low lipoxygenase activity was 64~76% or 54~62%, respectively. And selection for high lipoxygenase activity increased by 29.7~44.7%, whereas that for low ones decreased by 21.8~27.3%, respectively, when compared to random population. Clear effect in selecting of lipoxygenase activity was present in early generation.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.12
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• pp.1667-1673
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• 2012

The objective of this study was to estimate economic weights of Hanwoo carcass traits that can be used to build economic selection indexes for selection of seedstocks. Data from carcass measures for determining beef yield and quality grades were collected and provided by the Korean Institute for Animal Products Quality Evaluation (KAPE). Out of 1,556,971 records, 476,430 records collected from 13 abattoirs from 2008 to 2010 after deletion of outlying observations were used to estimate relative economic weights of bid price per kg carcass weight on cold carcass weight (CW), eye muscle area (EMA), backfat thickness (BF) and marbling score (MS) and the phenotypic relationships among component traits. Price of carcass tended to increase linearly as yield grades or quality grades, in marginal or in combination, increased. Partial regression coefficients for MS, EMA, BF, and for CW in original scales were +948.5 won/score, +27.3 $won/cm^2$, -95.2 won/mm and +7.3 won/kg when all three sex categories were taken into account. Among four grade determining traits, relative economic weight of MS was the greatest. Variations in partial regression coefficients by sex categories were great but the trends in relative weights for each carcass measures were similar. Relative economic weights of four traits in integer values when standardized measures were fit into covariance model were +4:+1:-1:+1 for MS:EMA:BF:CW. Further research is required to account for the cost of production per unit carcass weight or per unit production under different economic situations.