• Journal of Practical Agriculture & Fisheries Research
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• v.16 no.1
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• pp.135-141
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• 2014

Olive flounder (Paralichthys olivaceus) has a great potential value for aquaculture in Korea. The theoretical sex ratio of this flounder is close to 1:1 as it is in many other type of fish. However, according to the size selection during artificial seedling production, there is a possibility of unbalanced sex ratio. The actual flounder culturing needs female seedlings because of faster growth than male in economically. However, little is known about the sex ratio of cultured flounder. The six populations consisted of three wild populations and three cultured populations were analyzed for investigating the sex ratio. The sex ratio of wild populations ranged from 1.10 to 1.93 in female and 0.52 to 0.91 in male. And the sex ratio of cultured populations ranged from 0.20 to 2.15 in female and 0.46 to 4.88 in male. This result indicated that the sex ratio of cultured flounder varies depending on the size selection method.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.4
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• pp.434-440
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• 1996

This experiment were conducted to elucidate the damage by viviparity during grain filling on grain quality and hulling recovery and to understand the varietal differences of viviparity and the effect of extractive from rice hull of hardly viviparous varieties on seed germination and seedling growth. Ten rice cultivars, such as three indica, four japonica and three Tongil-type rices, were used in this study. The brown rice yield was decreased along with increasing the artificial viviparous treatment periods. At six days after treatment, brown rice yield of Daeseongbyeo was reduce 20% as compared with control. The ratio of head rice was 41.3% at six days after viviparous treatment with $25^{\circ}C$ temperature and over 95% relative humidity, while it was 99.5% in control. Varietal differences of viviparity in three rice groups were ranged from 1.1 to 5.2% in indica rices, 9.2 to 79.7% in japonica rices and 2.1 to 63.7% in Tongil-type rices. Methanol extractives from rice hull of IR36, Shinunbongbyeo and Jungwonbyeo inhibited significantly the germination of Deaseongbyeo.

• Korean journal of applied entomology
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• v.12 no.1
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• pp.29-32
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• 1973

This experiment has been carried out to establish the most effective rearing method of rice stemborer, Chilo suppressalis (Walker) on artificial diets under the aseptic condition. The results obtained were summarized as follows: 1. Semi·synthetic diet was giving better results in the weight of matured larvae (96.4mg), emerging rate$(96.7\%)$ and number of egg masses (2.6) than other diets studied. 2. Number of egg masses and hatching rate were significantly increased on the semi-synthetic diet and chemically defned diet, and it may be due to the choline chloride in the diets, 3. Rice seedling was used as a convenient food material. However, it requires more labours and causes more damages of larvae in replacement of fresh seedlings. 4. A different result in larval weight and pupation rate was observed between simplified diet no. 1 and diet added with chlorella. 5. Simplified diet resulted in low hatchability in the second generation, which may be due to the mulnutrition of the diet for adults. 6. The pupation rate was significantly decreased by infection of microorganisms on matured larvae.

• Journal of Life Science
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• v.30 no.3
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• pp.291-297
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• 2020

This study was conducted to develop microsatellite markers in Seriola quinqueradiata using next-generation sequencing. A total of 28,873,374 reads were generated on an Illumina Hiseq2500 system, yielding 7,247,216,874 bp sequences. The de novo assembly resulted in 466,359 contigs. A total of 132 contigs (0.43%), including 60 microsatellite loci, were derived from 30,729 contigs longer than 518 bp. A total of 60 primer sets were designed from the 132 microsatellite loci. A total of 15 polymorphic nuclear microsatellite loci were chosen to evaluate population genetic parameters in the parents and offspring. The mean number of effective alleles was 18.5, ranging from 11 to 30. The observed heterozygosity (H_O) and expected heterozygosity (H_E) ranged between 0.431 and 0.972 with an average of 0.812 and from 0.782 to 0.949 with an average of 0.896, respectively. No significant linkage disequilibrium was observed after Bonferroni revision in any loci. The results show that the 15 polymorphic nuclear microsatellite markers can be used to study the population and conservation genetics of S. quinqueradiata in Korea. To ensure the success of artificial seedling production technology, genetic variations between the parent and offspring populations should be monitored, and inbreeding should be controlled.

• Journal of Bio-Environment Control
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• v.16 no.2
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• pp.135-141
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• 2007

Although the result of the tree height growth after water treatment, Fraxinus rhynchophylla has little affection by the artificial water treatment, the growth showed decreased tendency as the soil moisture decreased, and F. mandshurica showed high growth in relatively high soil moist $78{\sim}90%$ treated area. The growth of root collar diameter of F. rhynchophylla and F. mandshurica also showed decreased tendency as soil moisture decreased. The changes of biomass according to dry weight of root, stem, leaves of F. rhynchophylla demonstrating statistical significance as moisture contents of soil is lower showing decreased biomass tendency and in the treatment of $78{\sim}90%$(A) moisture content showed more than double the higher biomass compare to the treated area of $18{\sim}30%$(D) moisture contents. Also F. mandshurica showed statistical significance in A and D treatment demonstrating differences among each treatment. This can be purported to have physiological effects like weakening of seedling and softening of tissues including leaves as soil moisture decreased. Ultimately it is regarded to the main reason of unsatisfactory growth for F. rhynchophylla and F. mandshurica that are weak to drought resistance. SLA, which is one of the special traits of leaf area of F. rhynchophylla, didn't show statistical significance between moisture process, it demonstrated decreased tendency as the moisture content interval is minimal. LAR and LWR showed increased tendency while moisture content didn't show statistical significance between treatments as they are minimal.

• Journal of Aquaculture
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• v.11 no.2
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• pp.203-212
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• 1998

As seed production program is growing prosperously in various fishes in southern Korea, disease problems in larval and juvenile stages have emerged as a new research object. The following results were obtained from investigation about environmental factors related to mass mortalities of young Kinki red seabream, Pagrus major in process of artificial seedling production. Total length of red seabream larvae hatched was 2.93mm, and became 18.83~20.12mm at day 40. The first noticeable mortality of red seabream larvae (7.98~9.37mm) occurred in 25~30 day-old fish with the survival rates of 59.8~60.3%. Thereafter the mortality of larvae decreased, survival rate was 20.5~25.45% in day 40. After 20~30 days, the quality of pond water was bellow II class. During the experimental period COD, $PO_4$-P, $NO_2$-N, $NO_3$-N and $NH_$-N increased up to 3, 7, 34, 6 and 8 times, respectively, compared to initial ones. The number of viable bacteria in pond water and seabream larvae were $6.3{\times}10^6$~$2.3{\times}10^7$ cfu/ml, 4.3~$7.4{\times}10^6$ cfu/g in day 25, respectively. Among the isolated bacteria from the diseased red seabream in day 25, Vibrio spp. was considered to be the causative organism. External symptoms of this disease were floated, spined near the surface and inflated abdomen. When the isolated strain of the Vibrio was bathed to seabream larvae, $LD_50$ of seabream larvae was over $10^6$ cfu/ml of Vibrio spp.

• Journal of Korean Society of Forest Science
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• v.94 no.3 s.160
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• pp.178-182
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• 2005

To identify the seedlings from controlled pollination between one paternal tree and three maternal trees of Japanese red pine, cpSSR markers of the paternally inherited haploid genome were analyzed in two year old 114 seedlings of full sib families. Individual specific DNA fingerprint like haplotypes of the parental trees were determined by PCR with three cpSSR primers. Haplotypes of the 114 seedlings were also identified by PCR with the same primers. On the basis of the comparison of cpDNA haplotypes of the 114 seedlings with those of the parental trees, 14 seedlings revealed to have distinguished haplotypes from those of the paternal tree. It was tentatively concluded that they were generated via pollination with the non-paternal trees. A seedling of Gangwon30 revealing non-paternal haplotype might have been generated via self pollination with the pollens of maternal tree through improper emasculation or contamination during artificial pollination. DNA fingerprint like cpSSR profiles observed in this study could be successfully applied to the various plant forensic analyses, such as identification of siblings of individual trees, asexually reproduced ramets of a specific clone, vegetatively propagated individuals via tissue culture, and pure full sib progenies.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.54 no.3
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• pp.320-326
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• 2009

The crops showing hard seed character have high seed viability after seed storage for long period. The low germination rate due to hard seed coat, however, cause a problem of low seedling establishment in field condition. Three legumes used in the experiment, lablab bean (Dolichos lablab L.), asparagus bean (Vigna sesquipedalis L. Fruwirth), and soybean (Glycine max L. Merr.), showed low germination rate (26, 17, and 5%, respectively) due to thick and hard seed coat. In this study artificial treatment for breaking dormancy was tested in hard seeds. The effect of proper treatment was various depending on species. The germination rate of lablab bean was highly improved up to 94% by soaking into water for 24 hours. In the case of asparagus bean, the rate was increased up to 90% by soaking for eight hours near boiling water until it cools. The germination rate of small hard seed soybean was increase to 96% by soaking into concentrated sulfuric acid for 10 minutes. Ultrastructural change revealed by scanning electron microscope (SEM) reflects that the structure of micropyle was changed and water uptake was facilitated with all treatments tested in the experiment. Especially, sulfuric acid treatment resulted in the degradation of micropylar tissue. These results demonstrate that the artificial treatment including sulfuric acid and (hot) water soaking treatment for promoting water uptake can be applied to improve seed germination in legume seed with thick and hard seed coat.

• Journal of Korean Society of Forest Science
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• v.55 no.1
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• pp.22-29
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• 1982

Two ectomycorrhizal fungi, Pisolithus tinctorius and Thelephora terrestris, were introduced form U.S.A. and inoculated to five pine species in Korea to evaluate the reported growth stimulation of host plants after inoculation. These fungi were grown as mycelial inoculum in large quantity and ioculated to the fumigated nursery soil just before seed sowing. At the end of the first growing season. Pisolithus stimulated the height growth of Pinus densiflora. P. thunbergii. P. rigida, and P. rigida x teada by55, 36, 69, and 37%, respectively, compared with control seedlings with no fumigation and no inoculation. When the growth stimulation was expressed with dry weight, Pisolithus increased dry weight of P. densiflora and P. rigida x taeda by 143% and 128%, respectively, over control seedling. Thelephora failed to stimulate growth of inoculated plants. Pinus koraiensis did not respond to the inoculation during the first growing season. It is concluded that artificial inoculation of nursery pine trees with selected mycorrhizal fungi should be seriously considered to improve the quality of planting stocks and to stimulate early plant growth. The potential for use of Pisolithus in reforestation on adverse sited is also discussed.

• Journal of Bio-Environment Control
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• v.27 no.4
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• pp.341-348
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• 2018

To investigate the effect of light sources on the growth and photosynthesis of the dwarf apple rootstock M.9 for the production of standard seedlings, the plants were cultivated in a controlled environment for 6 weeks. The sources of light are six treatments [Red (R), Blue (B), White (W), RBUV (R7B3 containing UV-A), RBW (R3B1W1), SMF (high pressure sodium + metal halide + fluorescent lamp) under $154{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$. Growth characteristics of apple seedlings varied depending on artificial light source at 3 weeks and 6 weeks. The plant height of apple seedling was high in the R, RBUV, RBW, and SMF light sources at 3 weeks, and in the R light at 6 weeks. There was no significant difference on stem diameter among the treatments at 3 weeks, but showed high in RBUV and RBW light at 6 weeks. Leaf number was the highest in RBUV light at 3 and 6 weeks. The chlorophyll content (SPAD value) was high in the B and RBUV light at 3 weeks, but it was not significant at 6 weeks. The growth rate to height of the R light (1.12mm/day) was the highest among the treatments, followed by RBUV, RBW, SMF, W and then B. Leaf area was the highest in RBUV and RBW lowest in B. Specific leaf area was high in W and fresh and dry weight were high in RBUV. The photosynthetic rate at 6 weeks was highest in the B and lowest in the R. Stomatal conductivity and transpiration rate were higher in the B and W compared to the other light sources. Therefore, we are considered that light sources for growth of dwarf apple rootstock M.9 seedlings are suitable the R, RBUV, and RBW light sources with a high mixing ratio of Red and Red +Blue.