• Korean Journal of Ichthyology
• /
• v.5 no.1
• /
• pp.113-121
• /
• 1993

Cytogenetic studies and hybridization experiment using two populations of Oryzias latipes from Korea were conducted in order to examine their systematic positions. In the chromosome number of specimens examined. O. sinensis had 46 with a pair of large metacentrics and O. latipes had 48 chromosomes without a pair of large metacentrics. However, the diploid chromosome number of the hybrid between O. latipes and O. sinensis was 47 and they had a large metarcentric chromosome in their karyotype. In the $F_2$ hybrids, distribution of chromosome number was variable among individuals. Hatching rates showed little difference between control and hybrids. However, hatchiabilties of $F_2$ hybrids were decreased by 83.3% as compared with $F_1$ offspring. Incidence of abnormal larvae was increased by 15.3% as compared with their parents. These results indicate that the two karyotype populations formerly regarded as two subspecies would be two distinct allopatric sibling species O. sinensis, and O. latipes.

• Korean Journal of Plant Tissue Culture
• /
• v.24 no.5
• /
• pp.257-262
• /
• 1997

Intergeneric crosses over 34 cross combinations between genus Brassica and Raphanus were made. Ovules taken out of crossed were cultured on MS media supplemented with 1.0 mg/L GA and BA. Germination of embryo from ovule culture was not influenced by BA and GA in medium but by parental characters in its cross combination. Use of Raphanus sativus cv. Daibyosobudore and Jungkukcheongpi showed low embryo germination when they were used as male part. Cross combination with Brassica juncea as male parent showed slightly increased germination compared to other cross. These results indicated that embryo germination in ovule culture was not much influenced by casein hydrolysate, malt extract, BA, kinetin and glutamine in the medium, but parents in combination were key factor for increasing embryo germination.

• Journal of Aquaculture
• /
• v.9 no.2
• /
• pp.125-132
• /
• 1996

A study was carried out to test sex ratio of the progeny that were induced by the artificial fertilization between normal female and gynogenetic diploid eggs and sex-reversed gynogenetic diploid male sperm. Sex reversed gynogenetic diploid males were produced successfully in gynogenetic diploid female by immersion treatment with $17{\alpha}$-methyltestosterone at the concentration of 10 pub from $13.5{\pm}0.22$ mm to $57.6{\pm}5.1$ mm in total length. In $F_1$ progeny test, matings between normal females and sex-reversed gynogenetic males were not produced all female, but matings between gynogenetic diploid females and sex-reversed gynogenetic males were produced all female populations in six out of eight groups and two lots produced $96.9\%$ and $95\%$ female. These data showed that all-female populations were produced by crossing between gynogenetic diploid female and sex reversed gynogenetic diploid male.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.50 no.spc1
• /
• pp.112-117
• /
• 2005

This study was conducted to see the feasibility of breeding for sprout soybean cultivar with minimum benny flavor using lipoxygenase-less lines. Lipoxygenase-less cultivar Jinpumkong2 was crossed by lipoxygenase containing Gwangankong, Sebaeknamulkong, and Pureunkong as paternal parent and 24 lipoxygenase-less lines derived from those 3 combinations were selected and those lines were evaluated with their parental cultivars. Germination rate showed no difference between lipoxygenase-less lines and their parental cultivars, however, rates of normal sprout of those and Jinpumkong2 were 63 and $56\%$, and were lower than that of paternal parents. Hypocotyl length of those was same as Jinpumkong2, however, shorter than paternal parents. Texture characteristics including hardness, cutting force and mastication of 96 hour-cultured sprout of lipoxygenase-less lines showed higher value than that of their parental cultivars. Lipoxtgenase isozyme was not detected in the sprout cotyledon of lipoxygenase-less lines, however it was observed in the sprout hypocotyl of all the used genotypes. Though lipoxygenase activity in the seed of lipoxygenase-less lines was lower than that of Jinpumkong2(0.477, ${Delta}A$ 234 nm min-1 mg meal-1),2 lines revealed more than 0.5 value. Lipoxygenase-activity of 2 day-cultured sprout(both cotyledon and hypocotyl) was the highest, decreased in 3 days after culture and re-increased thereafter. Several lipoxygenase-less lines with lower lipoxygenase activity of sprout than Jinpumkong2 were selected and this suggested the possibility of breeding lines for soy-sprout with low benny flavor.

• Korean Journal of Organic Agriculture
• /
• v.23 no.1
• /
• pp.43-58
• /
• 2015

This study is conducted in order to select the varieties that can supplement problems related with organic cultivation of bulb onion (Allium cepa L.). 15 test varieties were selected considering rural preference, breeding line, breeding company, open-pollinated cultivar, F1 hybrid cultivar of either domestic or foreign products. Onion varieties were assessed in 5 criteria which are : growth of plants in low temperature, freezing injury resistance, resistance to physiological disorder such as bolting and doubled bulb, lodging index during harvest, and marketable yield. As a result, e-Joeun, Katamaru, Pop, Art, Singihan among F1 hybrid cultivars and Changnyeongdaego, Seouldaego, and Chunjujunggo among open-pollinated cultivars were selected as more suitable varieties for the organic cultivation. Although Sunpower cannot be selected in varieties those are suitable for organic cultivation, it showed excellent traits in the bulb characteristics. No significant differences were found between open-pollinated cultivar and F1 hybrid cultivar except growth of plants in low temperature (plant sheath diameter) and lodging index during harvest (May 24th). And no significant differences were recognized between domestic varieties and foreign varieties except missing plant ratio after wintering.

• Journal of Embryo Transfer
• /
• v.18 no.1
• /
• pp.61-68
• /
• 2003

Considerable attention has been focused on the cryopreservation of semen and estrus induction in dog, as consequence of poor productivity caused by long anestrus period, in order to enhance the productivity of youngs and to preserve the breeds. The objectives of this study were to improve reproductive efficiency of artificial insemination with fresh- and frozen-semen following estrus induction in dog. Fifty infertilie dogs (age 2~3 years) were selected fur the study and divided into three different estrus induction treatment groups. Group 1 : dogs (n=15) were given clomifene (0.1 mg/kg) orally f3r five days at 12 hr intervals. Croup 2: dogs (n=15) were given bromocriptine (50 $\mu$g/kg) orally for five days at 12 hr intervals, followed by single injection intravenously of 500 IU GnRH (Croup 3, n=20) when pro-estrus occurred. After being treated, the dogs were evaluated fur the rates of estrus induction and time interval lapses from treatment to beginning of the pro-estrus. The rates of pregnancy in estrus inducted dogs mated naturally compared to those inseminated artificially with ejaculated fresh semen and frozen-thawed semen. Estrus detection was performed using the method of vaginal smear and confirmed by the plasma progesterone assay. Pregnancy was confirmed by ultrasonograpy on day 25, 35 and 55 post insemination. The ejaculated semen was exposed to a mixture of Tris extender with cryoprotectant (Trisma, 81 mM; TES, 209 mM; citric acid, 6 mM; glucose, 5 mM; glycerol, 8%) and cryopreserved gradually by slow-cooling at 17 co above the surface of liquid nitrogen (L$N_2$) for 23 min. The use of fresh semen, the pregnancy rates were observed 66.6, 66.6, 75.0 and 83.3% in natural estrus, clomifene induced, bromocriptine induced and a combination of GnRH and bromocriptine, respectively. The use of frozen-thawed semen, the pregnancy rates were observed 66.6, 33.3, 50.0 and 60.0% in natural estrus, clomifene induced, bromocriptine induced and a combination of GnRH and bromocriptine, respectively. No difference was observed in the number of offspring produced among natural estrus and treated groups inseminated with fresh or frozen-thawed semen. In conclusion, there was no significant differences in the pregnancy rate of dogs between group treated with a combination of GnRH and bromocriptine and group treated clomifene or bromocriptine only. However, frozen-thawed semen can be used successfully fur artificial insemination in dog.

• Journal of Life Science
• /
• v.16 no.3 s.76
• /
• pp.527-533
• /
• 2006

The purpose of this study is to improve the culturability of a indica type rice cultivar, IR 36, using DNA marker associated with the ability of plant regeneration in anther and seed culture. The varietal difference of ability of callus formation and plant regeneration was investigated in anther and seed culture of 8 rice cultivars. Three japonica rice cultivars showed to have better culturability than those of tongil and indica type genotypes. But two indica/japonica lines, 'MGRI 079' and 'MGRI 036', which were selected to have good culturability in previous study showed the highest regenerability (20%) in anther culture of 8 rice cultivars. Thirty four $BC_2F_4$ lines were selected by marker screening using RZ400 for 100 $BC_2F_4$ lines derived from a cross $'MGRI\;079/IR\;36^{^*3}'$. The frequency of callus formation of 30 $BC_2F_4$ lines was higher than those of 'IR 36' in anther culture of the selected $BC_2F_4$ lines. The ability of plant regeneration of 15 lines was higher than that of 'IR 36' in the seed culture of 34 $BC_2F_4$ lines. A promising line, $BC_2F_4-28$, was selected to have better culturability in the anther and seed culture of the $BC_2F_4$ lines. The heading date and grain shape of the $BC_2F_4-28$ was similar to 'IR 36'. In seed culture of 50 $BC_4F_3$ lines derived from a rice cross $'MGRI\;079/IR\;36^{^*5}'$, 11 lines including $BC_4F_3-3$ showed to have higher regenerability compared with 'IR 36'. The highest frequency of plant regeneration (11%) was obtained from $BC_4F_3-46$ in seed culture of the $BC_4F_3$ lines.

• Korean Journal of Agricultural Science
• /
• v.8 no.1
• /
• pp.51-63
• /
• 1981

The results of a crossbreeding experiment with a total of 315 litters and 325 pigs of Berkshires, Hampshires, Durocs, Landraces, Large Whites, eight different two-breed crosses and twelve different three-breed crosses, produced at Livestock Experiment Station from 1975 through 1979, are summarized as follows. 1. Number born alive per litter was largest in the D♂${\times}$(Lw♂${\times}$L♀) $F_1$ ♀ mating, followed by the D♂${\times}$(H♂${\times}$L♀) $F_1$ mating, and smallest in the Hampshires. The pigs in the 3rd-6th parities had larger litter size at birth than those in other parities. 2. Birth weight of pig was heaviest in L♂${\times}$Lw♀ mating and lightest in the Large White. The total litter weight at birth was heaviest in the D♂${\times}$(Lw♂${\times}$L♀) $F_1$ ♀ mating, followed by D♂${\times}$(H♂${\times}$L♀) $F_1$ ♀ and Lw♂${\times}$L♀ matings, and was smaller in Hampshires and Birkshires. 3. Litter size at weaning was largest in the D♂${\times}$(Lw♂${\times}$L♀) $F_1$ ♀ mating, followed by D♂${\times}$(H♂${\times}$L♀) $F_1$ ♀ and Lw♂${\times}$L♀ matings, and was smaller in Durocs and Hampshires. The pigs in the 3rd-6th parities had larger litter size at weaning than those in other parities. 4. The total litter weight at weaning was heaviest in the D♂${\times}$(Lw♂${\times}$L♀) $F_1$ ♀ mating, followed by H♂${\times}$(Lw♂${\times}$L♀) $F_1$♀ and Lw♂${\times}$L♀ matings, and was lighter in Durocs and Hampshires. The weaning weight of pig was largest in D♂${\times}$(Lw♂${\times}$L♀) $F_1$ ♀ mating and lightest in L♂${\times}$H♀ mating. 5. Survival rate at weaning was highest in L♂${\times}$Lw♀ mating, followed by D♂${\times}$(L♂${\times}$H♀) $F_1$ ♀ and D♂${\times}$(H♂${\times}$L♀) $F_1$ ♀ mating, and was lowest in Durocs. 6. The three-breed cross from D♂${\times}$(H♂${\times}$L♀) $F_1$ ♀ mating had the highest average gain and lowest feed requirement per unit gain, followed by the D♂${\times}$(Lw♂${\times}$L♀) $F_1$ ♀ and H♂${\times}$(Lw♂${\times}$L♀) $F_1$ ♀ matings. The Birkshires and Landraces ranked lowest among the 25 mating groups compared for both of the traits. Males had higher average daily gain than females by about 0.06kg and had lower feed requirement by about 0.14. 7. The three-breed crosses from D♂${\times}$(H♂${\times}$L♀) $F_1$ ♀, D♂${\times}$(Lw♂${\times}$L♀) $F_1$ ♀ and H♂${\times}$(Lw♂${\times}$L♀) $F_1$ ♀ matings reached 90kg body weight at younger age than the other groups. The D♂${\times}$(H♂${\times}$L♀) $F_1$ ♀ group reached 90kg at younger age than the Landrace by 39 days. 8. The dressing percentage and lean meat percentage tended to be higher in H♂${\times}$(Lw♂${\times}$L♀) $F_1$ ♀, H♂${\times}$L♀ and L♂${\times}$B♀ matings compared to the other mating groups. The loin-eye area was largest in the Lw♂${\times}$L♀ mating and smallest in the B♂${\times}$L♀ mating. Males had higher dressing percentage, higher lean meat percentage and lion-eye area than females. The backfat was thinnest in purebred Hampshire and was thickest in B♂${\times}$L♀ mating. 9. The results obtained in this study suggest that the two-breed cross from Lw♂${\times}$L♀ mating, and the three-breed crosses from D♂${\times}$(Lw♂${\times}$L-♀) $F_1$ ♀ and D♂${\times}$(H♂${\times}$L♀) $F_1$♀ matings are superior crossbreds for reproductive and pork prodnction performance.

• Journal of Animal Science and Technology
• /
• v.51 no.5
• /
• pp.353-360
• /
• 2009

When 14 microsatellite (MS) markers were applied in the identifying test for 480 Hanwoo, the discriminating power was estimated as $3.43{\times}10^{-27}$ based on the assumption of a random mating group (PI). This rate is 1,000 times higher than that of 60 single nucleotide polymorphism (SNP) markers. On the other hand, the power of the 60 SNP markers was estimated as $4.69{\times}10^{-20}$ and $8.02{\times}10^{-12}$ on the assumption of a half-sib mating group ($PI_{half-sibs}$) and a full-sib mating group ($PI_{sibs}$), respectively. These powers were 10 times and 10,000 times higher than those of the 14 MS markers. The results indicated that the total number of alleles (MS vs SNP = 146 vs 120) acted as a key factor for the discriminating power in a random mating population, and the total number of markers (MS vs SNP = 14 vs 60) was a dominant influence on the power in half-sib and full-sib populations. In the Hanwoo population, in which it was assumed that the entire population is the enormous half-sib group formed by the absolute genetic contribution of a few nuclear bulls, there will be only a 10 times difference in the discriminating power between the 14 MS markers and the 60 SNP makers. However, the probability of not excluding a candidate parent pair from the parentage of an arbitrary offspring, given that only the genotype of the offspring ($PNE_{pp}$) was 1,000 times higher as shown by the 14 MS markers than that by the 60 SNP markers. The strong points of SNP makers are the stability of the variation (low mutation rate) and automation of high-throughput genotyping. In order to apply these merits for the practical and constant Hanwoo identity test, research and development are required to set a cost-effective platform and produce a homemade apparatus for SNP genotyping.

• Korean journal of applied entomology
• /
• v.12 no.1
• /
• pp.1-21
• /
• 1973

Some experiments were conducted to investigate the effects of the chemosterilant, hempa, on the biology of the rice weevil, Sitophilus oryzae L., and the transmission of the lethal factors in the progeny. One to three days old adult males were fed on the wheat grains treated with concentrations of 0.0625, 0.125, 0.25, and $0.5\%$ of hempa water solution. The effects of the treatment on the mortality, longevity, and the performance of oviposition were examined for the Pl generation, and the hatchability and mortality in the postembryonic development were also tested in the $F_1,\;F_2,\;BC_1,\;F_3,\;and\;BC_2$ generations to analyze the inheritance of the lethal factors. The results obtained were summarized as follows. (1) The average longevity of the treated males were ranged from 26.6 to 30.4 days, and indicated no statistical differences. (2) The mortality of the treated males were ranged between $3.3\%\;and\;13.3\%$ and showed no statistical significance. (3) The overall mean number of eggs laid by a female mated to a treated male with concentrations of 0.0625, 0.125, 0.26 and $0.5\%$ were 3.78, 4.05, 3.75 and 3.61 for the respective treatments, and they were not differ significantly from those of control which were 3.60 per female per 3 day period. The unmated female laid 1.91 in the same period, and significantly differ from those in other experimental groups. (4) The overall mean hatchability of the eggs laid by the females mated with males that had been treated with various concentrations of hempa were 86.82, 64.77, 53.47, 40.33 and $24.78\%$ for the respective concentrations of 0, 0.0625, 0.125, 0.25 and $0.5\%$. The hatchability decreased with the increasing concentrations. (5) The minimum hatchabilities were obtained from the eggs laid in the period of 10-12 days after treatment, then the hatchability increased showing some recovery. The recovery seemed to be very much delayed for the males which had been treated with the greater concentrations. Such a difference in hatchability might be related with the sensitivity of the developmental stages of the sperms, and broader spectrum in the stages and severer effects seemed to be associated with the increased concentrations. (6) The overall mean of larval mortality in the $F_l$ generation were 6.55, 17.89, 27.40, 35.42 and $52.17\%$ for the respective concentrations of 0,0.0625, 0.125,0.25 and $0.5\%$. And there was a tendency to increase in the mortality with the increase of concentrations. (7) The correlation coefficients between per cent sterile eggs and larval mortality for the experimental plots of 0.125, 0.25 and $0.5\%$ treatments showed r=+0.83 and +0.85, respectively, and it seemed to be close correlation between the lethal effects on the embryonic and post-embryonic developments. (8) Since the $SC_{50}$ of the sterile eggs was $0.133\%$ and $SC_{50}$ of the larval mortality was $0.565\%$, it was considered that tile lethal factors expressed more in the egg stages than the larval stages. (9) The ratio of female to male in the $F_l$ adults showed 100 : 125, 100 : 108 and 100 : 124 for the plots of 0.125, 0.25 and $0.5\%$ treatments, respectively. And it n·as considered that the sex ratio distortions might occur with the higher concentrations. (10) When the F, males originated 1.on the eggs had been laid by p, in the period of 16-18 days after treatment, were crossed to normal females $(BC_1)$ and made sib matings $(F_2)$, the per cent sterile eggs of the $BC_1$ generation were 13.88 and $33.04\%$ , and were 31.01 and $38.73\%$ for the $F_2$generation with the plots of 0.0625 and $0.125\%$ treatment, respectively. And these seemed to be a results of the $F_1$ individuals are carrying some chromosomal aberrations (11) The larval mortality was the highest in the $F_2$ plot and followed the female backcross plot, and the least in the male backcrosses. (12) The proportions of 1st and 2nd instar larvae among the larval development at tile 17th day after oviposition were 10.98, 27.26, 32.98 and $15.73\%$ in the normal female $\times$ normal male, $F_1$ female$\times$normal male, normal $female \;\times F_1$ male and $female \;\times F_1$ male plots, respectively. It was considered that the larval development might be delayed by the treatment in the 2nd generation. (13) Per cent larval mortality and sterile eggs were greater in the $F_2$ sib mating plots $(F_3)$ than both of $F_2$ backcrosses. Therefore, it seemed that some of the recessive lethal mutations might affect in the further generations. (14) The sterility, induced by the treatment of chemosterilant, hempa, was considered as the result of the dominant lethal mutations due to chromosomal aberrations such as translocation and/or deletion. The effects of these lethal factors seemed to be inherited tip to 3rd generation after treatment.