• Korean Journal of Animal Reproduction
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• v.11 no.3
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• pp.170-180
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• 1987

This study was undertaken to determine the effects of HCG and trout pitutary on sexual maturation and ovulation in the Korean loach, Misgurnus anguillicaudatus. Sexual maturation was observed in the fish treated with 250＋125 IU HCG within 2-4 days following injections. Total ovary weight and GSI were significantly greater in the hormone-treated fish than in the control fish. Furthermore, in the hormone-treated fish body weight increased by about 4-9 percent in 2 days. The water content of the ovulated eggs of the fish treated with 250＋125 IU HCG was also greater than that in the control. Changes in both macroscopic & microscopic appearnce of Korean loach ovaries are describled, as well as changes in the gonadosomatic index. Oocytes pass through seven cytologically changes in the relative stages. By examining these stages, it was found that oogenesis occures in two broad phases. The previtellogenic phasebegins as a new oogonia continues to arise following spawning. These rapidly develop into early perinucleolus oocytes, which in turn develop into resting stage oocytes. Most oocytes remain in this stage when they develop into late perinucleolus oocytes. The vitellogenic phase begins as these late perinucleolus oocytes become transformed into early maturing oocytes through the accumulation of yolk. The cytoplasm completely fills with yolk as oocytes reach the late maturing stage. Shortly before spawning the final hyaline stage of developing is reached. Changes in the microscopic appearances of the ovaries were well correlated with changes in both gonadosomatic index and macroscopic appearance.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.2
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• pp.259-266
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• 2005

Steers (n=335) of known genetic backgrounds from four fundamentally different growth types were subjected to two production systems to study differences in carcass traits. Growth types were animals with genetic potential for large mature weight-late maturing, intermediate mature weight-late maturing, intermediate mature weight-early maturing and small mature weight-early maturing. Each year, in a nine-year study, calves of each growth type were weaned and five steers of each growth type were developed on pasture or feedlot and slaughtered at approximately 20 and 14 months of age, respectively. Data collected were pre-slaughter shrunk body weight (SBW); hot carcass weight (HCW); dressing percentage (DRESS); fat thickness at the $12^{th}$ and $13^{th}$ rib interface (FAT); percentage kidney, pelvic, and heart fat (KPH); longissimus muscle area (LMA); marbling score (MARB); quality grade (QG); and yield grade (YG). Year and growth type were significant for all carcass traits. The growth type${\times}$production system interaction was an important source of variation in SBW, HCW; FAT, YG and MARB. The same interaction was non-significant for DRESS, KPH, LMA and QG. Carcass differences in measures of fatness were greater in the feedlot system than in the pasture system. These data could aid producers in matching beef growth type to the production system most suitable for efficient use of resources.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.11
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• pp.1746-1753
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• 2007

Steers (n = 335) of known genetic background from four fundamentally different growth types were subjected to two production systems to study differences in cooking loss (CL), tenderness, and chemical composition. Growth types were animals with genetic potential for large mature weight-late maturing (LL), intermediate mature weight-late maturing (IL), intermediate mature weight -early maturing (IE), and small mature weight-early maturing (SE). Each year, in a nine-year study, calves of each growth type were weaned and five steers of each growth type were developed on pasture or feedlot and harvested at approximately 20 and 14 mo of age, respectively. Data collected were CL and Warner-Bratzler shear force (WBS) for the Longissimus dorsi (LM), Psoas major (PS), and Quadriceps femoris (QF) muscles. Chemical composition was also determined from the right fore- and hindquarter. Data were analyzed using least squares analysis of variance for unequal subclass numbers. The beef growth $type{\times}production$ system interaction was significant for CL and WBS of the LM and ash in the lean trim of the forequarter. Growth types of LL and IL had greater (p<0.05) mean percentage CL in the PS and QF muscles than did IE and SE steers. Growth type LL had the highest (p<0.05) mean for both moisture and protein in the fore- and hindquarters; while SE had the lowest numerical mean value for moisture and protein in the fore- and hindquarters. Shear force of the PS did not differ (p>0.05) among steers of the four growth types. Increasing challenges to the cattle feeding industry may dictate that pasture development play a larger role in future production regimes. Producers should strive to match genetic growth type with available resources in order to remain viable and continue producing a quality product.

• Korean Journal of Soil Science and Fertilizer
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• v.30 no.3
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• pp.257-264
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• 1997

To find out the influence of different rice varieties on the emission of methane in the soil and the exudation of carbohydrates from root, the experiment was conducted on a fine silty, mesic family of Aeric Fluventinc Haplaquepts (Jeonbug series). The varities of rise involved one early maturing variety of Japonica type(namweon) and three mid-to-late maturing varieties of Japonica type and one mid-to-late variety of Indica${\times}$Japonica crossed. The methane flux over the rice canopy was measured according to the closed chamber method modified by Shin and the methane concentration in the soil was measured using porous cup installed in the soil. The carbohydrate exudates from root were measured under nutrient solution culture. It was found that the methane flux tended to be lower in early maturing varieties than in the mid-to-late maturing varieties, lower in indica${\times}$Japonica crossed variety than in Japonica type varieties. There was positive correlation between the number of tillers and the weight of roots of rice plant and methane flux. The correlation, however, tended to be greater between the weight of roots and methane flux. There was no significant difference in the concentration of methane in the soil under different varieties of rice, excepting one variety, Kehwa under which methane concentration was highest. In case of carbohydrate exudation, early maturing variety tended to be higher than other varieties, although the opposite was the case in methane flux.

• Applied Microscopy
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• v.31 no.1
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• pp.19-35
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• 2001

Outlines for plasma $estradiol-17\beta$, components, electrophoretic patterns, and ultrastructural changes were obtained in female rainbow trout (Oncorhynchus mykiss) during the seasonal reproductive cycles. Plasma $estradiol-17\beta$ under the natural conditions, exhibited distinct seasonal variation, peaking very late in vitellogenic season during September, decreasing gradually the halt of spawning in December, and ultimately falling during the early stages of seasonal ovarian recrudescence in February and March. This change in $estradiol-17\beta$ appeared to stimulate vitellogenin production as evidenced by increases in plasma calcium, phosphorus, glucose, albumin and total protein levels. The electrophoretic patterns of late maturing or spawning oocytes were stained more intensively than those of late perinucleolus oocytes (molecular weights of approximately 70,000 and 200,000). Two protein bands were found in the SDS-PAGE separation, coincident with the $estradiol-17\beta$ hormone peak. Gonadosomatic indices (GSI) significantly increased from October to January, and showed the highest peak in January, coinciding with the numerically abrupt increase of ripe ova in female. A positive correlation (r=0.701, p<0.01) was established between plasma $estradiol-17\beta$ levels and the gonadosomatic index during the prespawning. The highest level of hepatosomatic index (HSI) observed in December. During the breeding season (December), the gonadotropes were large and filled with GTH-containing inclusions such as granules and globules. The vitellogenic phase began as late perinurleolus oocytes became transformed into early maturing oocytes through the accumulation of yolk, and oocytes reached the late maturing stages as the ooplasm was completely packed with yolk. Marked ultrastructural changed in the granulosa cells during nuclear migration involve the dilation of the rough endoplasmic reticulum and the appearance of the rod-shaped mitochondria with tubular cristae. Microvilli (finger-like projections), from the zona radiata and from the oocyte grew, and made contact with each other in the pore canals of the zona radials during vitellogenesis, but were withdrawn as the zona radiata became more compact and devoid of pore canals during oocyte maturation. The zona radiata grew to a tripartite structure such as an outer thin homogeneous layer, and two inner thick helicoidal layers (zona radials interna and zona radiata externa). Under the normal conditions, the ovarian follicle influenced the histological development and periodical secretion of the hormones , sufficient for a oogenesis and gonadal steroid production.

• Journal of Environmental Science International
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• v.31 no.5
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• pp.413-422
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• 2022

To identify rice (Oryza sativa L.) cultivars suitable for Italian ryegrass (Lolium multiflorum Lam.)-rice double cropping systems, we investigated the yield and grain quality of four different midseason maturing rice cultivars ('Daebo', 'Haepum', 'Haiami', and 'Samdeog') and four midseason-to-late maturing rice cultivars ('Hyunpoom', 'Saeilmi', 'Saenuri', and 'Samkwang') in single rice cropping and Italian ryegrass-rice double cropping systems in paddy fields of Miryang, South Korea. We found that organic matter and available P₂O₅ content slightly decreased, whereas Na content increased, in the soil where Italian ryegrass was cultivated during winter compared to that in the soil that remained fallow during winter. The pH, electrical conductivity, organic matter, and contents of K⁺, Ca²⁺, Mg²⁺, and Na⁺ decreased, whereas the available P₂O₅ content slightly increased, in the soil where rice was harvested in both single and double cropping systems. However, compared to the optimum soil conditions for rice cultivation, available P₂O₅ and K⁺ content were high and Mg²⁺ content was low in both single and double cropping systems. At the heading stage, the culm length and leaf color slightly increased in most of the rice cultivars, whereas the panicle length and number slightly decreased, in the double cropped system. After harvesting, spikelet number and milled rice yield did not show a significant difference between single and double cropping systems. However, the ripened grain rate and weight per thousand grains increased slightly in the 'Saeilmi' and 'Samkwang' cultivars but remained either stable or slightly low in other cultivars in the double cropping system. The milled rice yield was high (> 500 kg/10a) in 'Daebo' and 'Haepum' among midseason maturing rice cultivars, and in 'Saeilmi' and 'Saenuri' among midseason-to-late maturing rice cultivars, in both single and double cropping systems. The head rice rate was high in midseason maturing rice cultivars in the double cropping systems, reaching > 70% in 'Haepum' and 'Haiami' cultivars, whereas it decreased in most midseason-to-late maturing rice cultivars (excluding 'Samkwang' cultivar), in double cropping systems. Particularly, it exceeded > 70% in the 'Saenuri' cultivar in both single and double cropping systems. The protein content in milled rice increased, whereas the amylose content either remained stable or slightly increased, in double cropping systems. The Toyo taste value decreased in all midseason-to-late maturing rice cultivars and slightly increased in the 'Daebo' and 'Haiami' cultivars among midseason maturing rice cultivars in double cropping systems. However, Toyo taste values in the 'Haepum', 'Haiami', and 'Saenuri' cultivars exceeding > 80% in both single and double cropping systems. Therefore, we recommend 'Haepum', 'Haiami', and 'Saenuri' cultivars as candidates for Italian ryegrass-rice double cropping systems due to high yield, head rice rate, and Toyo taste value.

• Journal of The Korean Society of Grassland and Forage Science
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• v.27 no.4
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• pp.257-262
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• 2007

The objective of this research was to develop a high yielding, early and medium-late flowering new hairy vetch(Vicia villosa Roth) varieties derived from an accession in Korea. Most vigorous early and medium-late flowering hairy vetch lines were selected and crossed by open pollination and their seeds were bulked and plants were reselected at Seongju in the Keongbuk and at Sacheon in the Keongnam. A performance trial was conducted to evaluate agronomic characteristics, forage quality and dry matter(DM) yield of new hairy vetch early-maturing 'Cold green' and medium-late maturing variety 'Cheong pa' at Seongju and Sacheon. 'Cold green' and 'Cheong pa' are hair but 'Haymaker plus' and 'Latigo' are nearly hairless. 'Cold green' has purple flowers while 'Cheong pa' has violet. The cold tolerance of 'Cold green,' 'Cheong pa' and 'Latigo' was higher than 'Haymaker plus' at Seong-ju, Keongbuk province, in inland region but there were a little differences at Sacheon, Keongnam province in southern coast region. Fifty percent-flowering dates of 'Cold green' and 'Haymaker plus' had earlier than others and 'Cheong pa' was earlier than 'Latigo'. The DM yield of 'Cold green' was higher than that of others, but 'Cheong pa' and 'Haymaker plus' had higher than 'Latigo' at Seong-ju(P<0.05). In Sacheon, The DM yield of 'Cold green' and 'Haymaker plus' was higher than others and 'Cheong pa' had higher than 'Latigo'.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.243-245
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• 2007

This study was begun to classify the paddy fields by the rice varieties and to monitor the temporal change in rice growth using SAR backscatter coefficients $({\sigma}^{circ})$. For nine fine-beam mode images of Radarsat-1 SAR, a growing period time-series of backscatter coefficients was set up from April to October in 2005, and was compared with the field-measured rice growth parameters such as LAI (leaf area index), plant height, fresh and dry biomass, and water content in grain and plant for 45 parcels in Dangjin-gun, Chungcheongnam Province, South Korea. The average backscatter coefficients for early-maturing rice varieties (13 parcels) were ranged from -18.17dB to -6.06dB and were lower than for medium-late maturing rice varieties during most of the growing season. At around the heading stage (July 30) for early-maturing rice, both rice crops showed the highest backscatter coefficient values and the difference was the greatest before harvesting early-maturing rice. The temporal difference in backscatter coefficients between rice varieties was expected to play a key role to identify early-maturing rice fields. On the other hand, comparison with field-measured rice growth parameters showed that the backscatter coefficients decreased or stayed on the plateau after heading stage even though the growth of rice canopy advanced.

• Journal of Aquaculture
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• v.2 no.1
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• pp.21-32
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• 1989

This study was undertaken to understand development stage of ovary and changes of hormone concentrations in the Israeli carp, Cyprinus carpio from Ferbruary to May. The results obtained in these experiments are as follows: 1. Serum LH levels began to increase sharply in March, coinciding with the onset of rapid ovarian development. 2. LH levels were well correlated with changes in gonadosomatic index. 3. Dramatic increase in gonadosomatic index occured during the months of March. 4. Ripe stage(Stage VII) rapidly increase in March. 5. Early perinucleolus oocyte rapidly develop into late perinucleolus oocytes in March. 6. The vitellogenic phase begins as these late perinucleolus oocytes become transformed into early maturing oocytes through the accumulation of yolk. 7. The cytoplasm completely fills with yolk as oocytes reach the late maturing stage. 8. Changes in the microscopic appearances of the ovaries were well correlated with changes in both gonadosomatic index and macroscopic appearance. 9. It is concluded from these observations that LH plays a major role in sexual maturating of the Israeli carp.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.5
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• pp.418-424
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• 1993

In order to test combining ability of the cytoplasmic-genetic male sterile(CGMS) and restorer lines with backgrounds of Korean japonica rice varieties, diallel crosses were made among the early maturing CGMS lines Sobaegbyeo A, Odaebyeo A, Gwanagbyeo A and Daeseongbyeo A, and the restorer lines Sobaegbyeo R, Odaebyeo R, Gwanagbyeo Rand Daeseongbyeo R, and among the medium maturing CGMS lines Hwajinbyeo A, Paldal A, Suwon 224 A and Iri 386 A and the restorer lines Hwajinbyeo R, Paldal R, Suwon 224 Rand Iri 386 R, and among the late maturing CGMS lines Nagdongbyeo A, Palkweng A, Hwacheongbyeo A and Milyang 97 A and the restorer lines Nagdongbyeo R, Palkweng R, H wacheongbyeo Rand Milyang 97 R. The fourty eight combinations of the hybrids, their parents and the maintainers were grown in field condition in 1992. General combining ability, relative specific combining ability and relative combining ability for yield of the CGMS and restorer lines were tested. Combining ability of the CGMS lines Odaebyeo A, Iri 386 A, Nagdongbyeo A and Palkweng A, and of the restorer lines Odaebyeo R, Hwajinbyeo R, Hwacheongbyeo Rand Palkweng R was relatively high. Heterobeltiosis for grain yield over the better parent of the early maturing hybrids ranged from -17 % to 15%, and that of the medium maturing ones from -4% to 22%, and that of the late maturing ones from -46% to 30% respectively, Standard heterosis over the standard variety of the early maturing hybrids ranged from -13 % to 12 %, and that of the medium maturing ones from 0 % to 26%, and that of the late maturing ones from -38% to 26% respectively, Positive and negative heterosis for grain yield of the hybrid rices were observed depending on cross combinations, In the positive heterosis hybrids, number of panicles per hill and number of spikelets per panicle contributed mostly to grain yield, while in the negative heterosis hybrids, spikelet fertility and 1000 grain weight were closely correlated to grain yield. Amylose content of the hybrid rices, maintainer and restorer lines was mostly lower than 20 %, and alkali digestion value was higher than 6.0. Grain appearance of the hybrids tested was similar to the korean japonica rice varieties.