• Asian-Australasian Journal of Animal Sciences
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• v.25 no.6
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• pp.772-784
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• 2012

Marker-assisted gene pyramiding aims to produce individuals with superior economic traits according to the optimal breeding scheme which involves selecting a series of favorite target alleles after cross of base populations and pyramiding them into a single genotype. Inspired by the science of evolutionary computation, we used the metaphor of hill-climbing to model the dynamic behavior of gene pyramiding. In consideration of the traditional cross program of animals along with the features of animal segregating populations, four types of cross programs and two types of selection strategies for gene pyramiding are performed from a practical perspective. Two population cross for pyramiding two genes (denoted II), three population cascading cross for pyramiding three genes(denoted III), four population symmetry (denoted IIII-S) and cascading cross for pyramiding four genes (denoted IIII-C), and various schemes (denoted cross program-A-E) are designed for each cross program given different levels of initial favorite allele frequencies, base population sizes and trait heritabilities. The process of gene pyramiding breeding for various schemes are simulated and compared based on the population hamming distance, average superior genotype frequencies and average phenotypic values. By simulation, the results show that the larger base population size and the higher the initial favorite allele frequency the higher the efficiency of gene pyramiding. Parents cross order is shown to be the most important factor in a cascading cross, but has no significant influence on the symmetric cross. The results also show that genotypic selection strategy is superior to phenotypic selection in accelerating gene pyramiding. Moreover, the method and corresponding software was used to compare different cross schemes and selection strategies.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.9
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• pp.1192-1196
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• 2004

In order to detect the molecular mechanism of heterosis in pigs, the mRNA differential display technique was performed to investigate the differences in gene expression of pig's Longissimus dorsi between the high-parent heterosis cross combination Landrace${\times}$Large White and the mid-parent heterosis cross combination Large White${\times}$Meishan. Three pig purebreds, Large White, Meishan, and Landrace and four types of reciprocal $F_1$ hybrids were analyzed using nine 3'-end anchored primers in combination with ten 5'-end arbitrary primers and nearly 7,000 reproducible bands were examined. The patterns of gene expression of each cross combination were analyzed and eight common patterns (fifteen kinds) were found. When the results from the two cross combinations were put together and compared, eight different typical expression patterns were observed, these indicated that the patterns of gene expression of these two cross combinations had obvious differences. Gene expression correlation and cluster analyses of the two cross combinations indicated that the gene expression of the mid-parent heterosis cross combination was correlated with maternal effect, but in the high-parent heterosis cross combination, paternal effect acted in the gene expression of the hybrids or the gene expression of the hybrids was biased towards one parent.

• Journal of Sericultural and Entomological Science
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• v.37 no.1
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• pp.10-15
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• 1995

Genetic characterization of Sri Lankan silkworm bivoltine population has not been at-tempted so far, since its sporadic introduction of bivoltine strains into the island, starting from the 1950's. Genetic structure of Sri Lankan population of mulberry silkworm Bombyx mori was investigated through estimation of general (GCA) and specific combining ability(SCA) and heritability(${h^2}_B$), on the economic quantitative characters from leading 8 inbreds and their 28 F1's in a half diallel cross, in an attempt to utilize the estimates in determination of future breeding methods and to predict the breeding value over the phenotypic value. It was found that the breeding population of the bivoltine silkworm in Sri Lanka has still maintained considerable amounts of additive gene action as well as nonadditive. For some time in the future, both breeding strategies of "selection without inbreeding" and also "inbreeding followed by crossing" should therefore be effective in genetic improvement of economic characters investigated. In addition, superior combiners in general and in specific F1′s were identified for each of 6 economic characters, to be immediately utilized in selection and also in cross breeding programs in Sri Lanka.

• FLOWER RESEARCH JOURNAL
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• v.16 no.2
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• pp.149-151
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• 2008

A new Phalaenopsis cultivar 'Little Dew' has been developed by a cross breeding and a line selection at the Flower Breeding Research Institute, Gyeongnam ARES from 2000 to 2007. Characteristics trials for this cultivar was carried out three times from 2004 to 2006. 'Little Dew' developed from a cross between Phal. 'Timothy Christopher' and Phal. amabilis showed white miniature type flowers and a multiflora shape. It has 3~4 flower stalks and many flowers, and long life span of flowers. This new cultivar was registered for commercialization in 2007 and would be cultured well in greenhouse conditions in Korea.

• Communications for Statistical Applications and Methods
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• v.9 no.3
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• pp.675-682
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• 2002

In this study, we develop the statistical analysis program for genetic analysis of diallel crosses data by SAS/MACRO, SAS/IML. Genetic analysis is to estimate of genetics parameters and heredity with reciprocal cross and without reciprocal cross. Statistical analysis program solve the problem of the difficulties on the data analysis in field denetics and breeding Therefore the user whoever want to analysis of data on genetics and breeding easily conduct the work saving time and suffering.

• 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.

• Animal cells and systems
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• v.14 no.4
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• pp.305-313
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• 2010

Pacific abalone Haliotis discus discus is an important fisheries resource in Jeju, Korea. For basic information about its current genetic status in relation to stock enhancement, the level and distribution of genetic variation between wild and released stocks of Pacific abalone in Jeju were examined at nine cross-species microsatellite markers including the use of two novel primers. High levels of polymorphism were observed between the two populations. A total of 146 different alleles were found at all loci, with some alleles being unique. The allelic variability ranged from five to 27 in the wild population and from four to 16 in the released sample. The average observed and expected heterozygosities were estimated to be 0.74 and 0.84 in the wild sample and 0.70 and 0.78 in the released sample, respectively. Although a considerable loss of rare alleles was observed in the released sample, no statistically significant reductions were found in heterozygosity or allelic diversity in the released sample compared to the wild population. Low but significant genetic differentiation was found between the wild and released populations. These results suggest that the intensive breeding practices for stock enhancement may have resulted in a further decrease in genetic diversity, and that the cross-species microsatellite markers used in this study represent a potentially efficient means for further genetic studies, providing beneficial information for the protection and management of H. discus discus.

• Korean Journal of Breeding Science
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• v.43 no.5
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• pp.368-374
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• 2011

Apricot (Prunus armeniaca L.) cultivars show a gametophytic self-incompatibility (GSI) system, like other fruit species of Rosaceae family. Thus, it is necessary to determine their S-genotypes in order for stable fruit set in commercial cultivation. S-genotypes of apricots were determined by PCR and test crosses. Three sets of consensus primers designed from Prunus S-RNases were used to amplify fragments containing the first and second S-RNase intron, respectively. Through the results obtained from the 3 PCRs, we could identify SI genotypes of 33apricot cultivars. Several cultivars such as 'Heiwa', 'Yamagata No.3' and 'Shinsuoomi' had the self-compatible (Sc) allele. Self-pollination tests revealed that cultivars with Sc allele were self-compatible. Cross-pollination tests confirmed that there was cross-incompatibility between the cultivars with the same S-genotypes. These results might be very useful for growers for effective pollination and for breeders using these in cross breeding programs.

• Journal of Radiation Industry
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• v.5 no.4
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• pp.285-295
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• 2011

Mushrooms belonging to macrofungi have been consumed by humans for their nutritional and medicinal values for centuries throughout the world. Mushroom farming is practiced in more than 100 countries of the world, with production increasing at a rate of 7% per annum. High yield and good quality are always the principal goals for agriculturally important crops, including mushrooms. Several breeding methods are employed for strain improvement such as mass selection based on the natural chance mutation and induced mutation (mutation breeding), protoplast fusion technology, cross breeding and transgenic breeding. However, mutation breeding has shown prominent success in crop plant improvement. Though several-hundred mutant crop varieties have been developed around the world, the mutation breeding of mushrooms is limited. This review paper explores the potential application of radiation on the development of mutant varieties of mushrooms for breeding with desired traits such as better quality and productivity.

• Journal of Veterinary Clinics
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• v.34 no.2
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• pp.126-131
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• 2017

This study investigated the incidence rate of umbilical hernia (UH) in pig farms and examined the effect of using them as breeding pigs on reproductive traits. The occurrence of UH ranged from 0.1% to 3.0% in pig farms investigated. UH pigs were found in almost all farms except for a single farm in Jeju Island. Spontaneously occurring UH pigs were selected and used for cross breeding tests. UH-related crosses and their progeny showed significant (P < 0.05) differences in gestation period, the numbers of piglets born and alive, and body weights at birth and $21^{st}$ day comparing to those of the control population. UH-related crosses showed longer gestation period, reduced numbers of piglets, and lighter body weights than those from the control population. Interestingly, reduced number of piglets was about one fourth, suggesting that UH inheritance might play a critical role as a lethal gene during embryogenesis. In addition, UH incidence rate in UH-related crosses was significantly (P < 0.05) higher than that in the control except for UH-cross3. However, in the progeny of control cross, a pig also had UH appearance, indicating that porcine UH might be inherited in recessive inheritance mode. Taken together, the results of this study indicate that UH is one of recessively inherited genetic defect that occurs at ordinary times in pig farms, suggesting that the use of UH animals as sire and/or dam may lead to economic losses due to increased gestation period, reduced numbers of piglets born and alive, and lower growth rates after birth of pigs.