• Journal of The Korean Society of Grassland and Forage Science
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• v.24 no.4
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• pp.301-308
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• 2004

This experiment was carried out to classify heading date of forage rye cultivars, and study agronomic characteristics, dry matter yield per ha and forage quality of winter rye cultivars in Suwon for 2 year from 2002 to 2003. The earliest cultivars among forage winter rye cultivars were Olhomil and Vitagrazer, which the heading date was April 21. The latest cultivar was Danko, which was May 5. Koolgrazer was April 26 and Homil 22 was April 30, respectively. Therefore, we classified the cultivars into three groups according to their heading date. The earliest group includes Olhomil, Vitagrazer, Paldanghomil, the middle group includes 5 cultivars which are Koolgrazer, Barrgazer, Maton, Wintergrazer and Homil22, and the latest group contains Humbolt and Danko. The number of tiller per $m^{2}$ of most cultivars were more than 1,000. The cultivar which has lowest tiller was Humbolt, which dry matter yield was the largest, and its tiller was 789. The lodging happened after each precipitation. Danko was the cultivar that has lowest lodging frequency. There has been little disease and insect and the difference in the quality of each cultivar. The yield of dry matters per ha of Humbolt was increased $123\%$, Vita grazer $121\%$, Maton $113\%$ comparing the standard cultivar, Kool grazer of 12,409kg, and Homil 22 was almost the same with the standard cultivar.

• Proceedings of the Korean Society of Grassland Science Conference
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• 1999.06a
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• pp.76-77
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• 1999

1996-1998년에 걸쳐 경기 수원, 경북 경산 및 제주에서 시험결과 우량품종으로 선발된 이탈리안 라이그라스의 생육특성과 건물수량 및 사료가치는 다음과 같았다. 월동률에 있어서 FL80(장려품종)이 중북부 지역인 수원에서 69%로 가장 낮았고 Marshall(장려품종) 및 Grazer 등이 가장 높았다. 숙기는 Grazer 및 FL80(장려품종)이 4월 중순에 출수가 시작되어 가장 조생종으로 평가되었다.(중략)

• ALGAE
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• v.32 no.1
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• pp.47-55
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• 2017

We explored feeding by the mixotrophic ciliate Mesodinium rubrum, heterotrophic nanoflagellates (HNFs), and small ciliates (<$30{\mu}m$ in cell length) on natural populations of heterotrophic bacteria in Masan Bay, Keum River Estuary, and in the coastal waters of the Saemankeum area, Korea when M. rubrum red tides occurred. We also measured ingestion rates of M. rubrum on cultured heterotrophic bacteria as a function of bacterial concentration in the laboratory. The ingestion rates of M. rubrum on natural populations of heterotrophic bacteria (2.3-16.8 bacteria $grazer^{-1}h^{-1}$) were comparable to or lower than those of co-occurring HNFs (10.7-41.7 bacteria $grazer^{-1}h^{-1}$), but much lower than those of co-occurring small ciliates (76.0-462.2 bacteria $grazer^{-1}h^{-1}$). However, the maximum grazing coefficient of M. rubrum ($0.245d^{-1}$) on natural populations of heterotrophic bacteria was much higher than that of small ciliates ($0.089d^{-1}}$), and slightly higher than that of HNFs ($0.204d^{-1}$). With increasing bacterial concentrations, ingestion rates of M. rubrum on cultured heterotrophic bacteria continuously increased, but became saturated at higher prey concentrations over $1-5{\times}10^6cells\;mL^{-1}$. The maximum ingestion rate of M. rubrum on cultured heterotrophic bacteria was 34.4 bacteria $grazer^{-1}h^{-1}$. Based on the present study, it is suggested that M. rubrum may be an important grazer of heterotrophic bacteria and sometimes have considerable grazing impact on natural populations of heterotrophic bacteria.

• Journal of environmental and Sanitary engineering
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• v.15 no.1
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• pp.1-6
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• 2000

A milky gray scum was observed at some water area of the lake Daecheong in the summer of 1997 and 1998. To identify a causing organism of scum and affecting factors, we observed the scum material by a phase contrast microscope and surveyed the phsico-chemical water quality during the outbreak of scum. The scum was found out to be clogging cysts of amoeboid protozoan, Asterocaelum sp.(Protozoea Sarcodina Aconchulinida), grazer of filamentous cyanobacteria, Anabaena genus. The protozoan scum appeared during Anabaena bloom period, which continued for a while. This protozoan was presumed acting as a regulator of Anabaena bloom in the lake Daecheong during the summer season. Moreover this is the first report on Asterocaelum sp. a grazing filamentous cyanobacteria occurred in Korean freshwater.

• Journal of The Korean Society of Grassland and Forage Science
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• v.14 no.1
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• pp.34-41
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• 1994

This experiment was carried out to select the $Sorghum{\times}Sudangrass$ hybrid of high productivity suited for soiling, and growth characteristics and productivity of 9 cultivars of introduced $Sorghum{\times}Sudangrass$ hybrids have been evaluated at the experimental forage field, College of Natural Science of Kon-Kuk university in Chungju over three years. The results obtained are summarized as follows : 1. NC855, Sordan79 and T. E haygrazer were taller than the other varieties as range from 209cm to 213cm. while Supergrazer was the shortest type as 173cm. Among the nine varieties used, NC855 and Pioneer 988 were classified as early maturing varieties, but G83F, FP5 and Supergrazer were classified as lately maturing varieties. 2. The stem diameter of Supergnzer and Sordan79 were thicker than the other varieties, while NC855, Garst757 and FP5 were thin. 3. The tillers of $Sorghum{\times}Sudangrass$ hybrids were ranged from 3.1 to 4.0 and NC855 and FP5 had 4.0 tillers per plant. The dead stubble of Sordan79 was the lowest as 4.0 percentage, while Supergrazer was the highest as 9.8 percentage(P<0.05). 4. GW9110G and T. E haygrazer were susceptible to lodging(P

• Journal of The Korean Society of Grassland and Forage Science
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• v.35 no.2
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• pp.99-104
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• 2015

This study was conducted to evaluate on agronomic characteristics, dry matter (DM) and digestible dry matter (DDM) yields of summer sowing sorghum hybrids (Sorghum bicolor (L) Moench) at Seongju in Gyeongbuk from 2013 to 2014. The experiment was arranged in randomized complete block design with three replications. Sorghum hybrids were seeded $31^{st}$ of July, 2013 and 2014. Sorghum hybrids were harvested on $3^{rd}$ November, 2013 and $5^{th}$ November, 2014. The observed average heading date was October 5, 8 and 9 for Sordan79, Sprint and SX17 respectively. The DM yield of 'SX17', 'Sordan79', and 'Sprint' was 24.2, 23,9 and 23.4 ton/ha, respectively and DM yield of those were significantly higher (p<0.05) than other three cultivars in 2013. DM yield of 'SX17', 'Sprint' and 'Sordan79' was 20.8, 20.0 and 19.3 ton/ha, respectively and DM yield of those was significantly higher (p<0.05) than other three cultivars in 2014. The DDM yield of 'SX17', 'Sordan79', and 'Sprint' was also higher (p<0.05) than other three cultivars in 2013 and 2014. ADF content of sorghum hybrids was low, whereas DDM was high. The results of this study indicated that traditional sorghum-sudangrass hybrids ('SX17', 'Sordan79') and sudan grass-sudangrass hybrid ('Sprint') than late flowering sorghum-sudangrass hybrid ('PACF8350') and sorghum-sorghum hybrids ('SS405', 'Sugar grazer') would be recommended for DM and DDM yields in the southern Korea.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2001.11a
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• pp.198-200
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• 2001

Grager-Induced colony formation was examined using strains of green alga Scenedemus dimorphus (Turpin) Kutzing. Alga was cultured in a medium with or without filtered water in which Daphnia magna or Moina macrocopa had been reared. Colony formation was obviously promoted in S. dimorphus by exposure to zooplankton filtered water (ZFW), showing in proportion to the volume of zooplankton filtered water in cultured media. The particle volume as well as the number of cells per one colony of S. dimorphus increased between 24 and 48 hours after exposure to ZFW, which were caused by an infochemical released from from Daphnia or Moina probably as a part of defense mechanism against zooplankton grazing.

• Korean Journal of Ecology and Environment
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• v.38 no.spc
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• pp.17-21
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• 2005

We investigated the diel periodicity in the drift in relation to body size by field survey using the fourth instar grazing larvae of Micrasema quadriloba Martynov (Trichoptera, Brachycentridae) as a material. Although the larvae showed nocturnal drift periodicity, drift density in the nighttime was only twice that in the daytime. In both time periods, smaller individuals drifted significantly more, and the drift individuals in the daytime was the smallest in size (P< 0.05 in Sheffe's F). We discussed whether the drift of the fourth instar larvae drift behaviorally or accidentally considering larval size and food depletion.

• Journal of The Korean Society of Grassland and Forage Science
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• v.18 no.1
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• pp.35-42
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• 1998

Eleven Italian ryegrass cultivars were examined for their genetic polymorphisms and phylogenetic relationships using randomly amplified polymorphic DNA (RAPD) markers. In RAPD analysis of 34 random primers, 96 of total 162 bands obtained from 16 primers were polymorphic and sizes of polymorphic band ranged between 0.5 and 1.5kb. Number of bands amplified per primer was varied from 3 to 16 and average number was 14.8. Phylogenetic relationship among cultivars based on the RAPD analysis was examined using UPGMA computer program. In pairwise genetic similarity test of 11 Italian ryegrass cultivars, Grazer and Orlando showed highest coefficient of genetic similarity as 0.740, whereas Marshall and Orlando was lowest as 0.438. Eleven Italian ryegrass cultivars were grouped into 3 major clusters and genetic distance of clusters ranged between 0.567 and 0.646, indicating low level of genetic variation.

• Journal of The Korean Society of Grassland and Forage Science
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• v.27 no.4
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• pp.313-322
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• 2007

The object of this experiment was to investigate the food habits of dairy goats fed with various roughage sources. The experimental trials were conducted at Chungnam National University in 2007. The experimental roughages include five sources and 25 species in all; grass sources: 5 species (Lolium perenne, Festuca arundinacea, Poa pratensis, Agrostis alba and mixed grass, legume sources: 5 species (Trifolium pratense, Medicago sativa, Trifolium repens, Melilotus officinalis and Vicia villosa), browse sources : 5 species (Quercus serrata Thunb., Prunus jamasakura Sieb., Quercus aliena Blume, Robinia pseudoaccacia and Pinus densiflora), weed sources: 5 species (Artemisia princeps Pampanini, Erigeron canadensis, Alopecurus aegualis Sobolewski, Echinochloa crusgalli var. frumentacea (Roxb.) Wight and Rumex crispus), and native grass sources: 5 species (Zoysia japonica Steudel, Agropyron tsukushiense var. transiens (Hack) Ohwi., Arundinella hirta (Thunb.) Tanaka, Miscanthus sinensis Anderss and Phragmites comunis Trin). Ten dairy goats(Saanen) were selected which had nearly the same body weight(average 31kg). Experimental roughages were prepared by 0.5kg per 1 species fed to dairy goats, and the experiment was carried out from 09:00 to 18:00. The chemical composition and dry matter digestibility of each roughage source and species were significantly different at the sampling area, plant species, growth stages and cutting period. The dairy goats ate more roughages which had low fibrous contents, but high dry matter digestibility. Among all the 25 species of roughages, the favorite intake species order by dairy goat was observed like this: perennial ryegrass, tall fescue and red clover, respectively, and the lower intake species order was Rumex crispus. On the other hand, compared to each roughage source, total intake amount by dairy goats was showed as forage grasses (59.0%) which contained grasses(33.3%) and legumes (25.7%), browse (19.6%), weeds (15.9%) and native grasses (5.5%). Based on the result, the food intake type of dairy goats seems to be closer to grazer type.