• Journal of the Korean Society of International Agriculture
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• v.30 no.4
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• pp.305-312
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• 2018

Clubroot, caused by Plasmodiophora brassicae, is one of the most crucial disease in Kimchi cabbage. Screening disease resistant genetic resources is necessary to develop disease resistant cultivars and conduct related research. We have evaluated the development of clubroot to the 120 genetic resources of Kimchi cabbage introduced from World Vegetable Center and five Asian countries using isolate of Plasmodiophora brassicae collected in Haenam fields in Jeollanam-do Province, Rep. of Korea. This isolate was determined race 2 using differential varieties reported by Kim et al., 2016. IT100384 and IT305623 showed strong resistance, lower than disease index (DI) 1.0. IT100385, 100439, and 135407 showed moderate resistance (1.0

• Journal of Sericultural and Entomological Science
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• v.9
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• pp.67-87
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• 1969

1. Objectives and Importance. Many silkworms have been damaged by nuclear polyhedrosis virus diseases thoughout the country every year causing a decease in cocoon production by approximately ten per cent per year. The damage caused by the infections virus has occured in spite of complete disinfection. In this respect, it is well known it is impossible, at the present time, to protect the silkworm from these virus infections through chemical and physical control methods. Therefore, this author has attempted to solve this urgent problem from the view point of heredity and breeding, discovering the different resistances and heritabilities among 120 stains collected from throughout the country, and selecting the ones with highest resistance for the basic materials in the silkworm breeding. 2. Results of work 1) The strains with strong resistance to the nuclear polyhedrosis virus diseases are N$_4$, N$\sub$15/, N$\sub$48/, C$\sub$55/ and Em. the log ED$\sub$50/ values of them vary between 0.799 and 1.611. The susceptible strains are N$\sub$20/, C$\sub$62/, N$\sub$76/, N$\sub$79/ and C$\sub$108/, the log ED$\sub$50/ values of them vary between 5.159 and 7.258. (Reference Table 4) The Japanese strain with a log ED$\sub$50/, value of 3.770 is the strongest, followed by the Chinese strain with a log ED$\sub$50/ value of 3.564. The weakest is the European strain with a log ED$\sub$50/ value of 3.3381. The direction coefficient of the regression equation of the susceptibility varies between 0.1 and 0.6, the uniformness of the resistance of the preserved strains of this country is comparatively low. The hereditary henomena of the resistance of each strain and the conerete method of its application for silkworm breeding main the subjects for later studies. 2) The content of water and ash in silkworm has not been correlated with the capability for resistance to the virus diseases(Reference. Table 8). but it is very significantly correlated with mortality rate (in common reaning). In the case of the silkworms which have just completed the fourth moulting the content of water and ash is not related to the mortality rate. In the case of the silkworms which have just completed the third moulting, however, the water( +0.326) and ash (+0.362) registered a high significance. The ash content in the first ($\div$0.520) and second ($\div$0.386) moults is highly significant but water content in both cases is not significant (Reference Table 7). 3) The No. 205 strain proved to be the best in character among the various F$_1$ hybrids. No. 204 was very good in strength but a little lower in cocoon character than the control. No. 212 was a little low in coccon character and mortality was average, but the cocoon harvest was the best among all the varieties offered for (Reference Table 9). 4), In short, the above mentioned strains which are known to have strong resistance to the virus disease are expected to provide basic data for breeding strong varieties. It is proposed that continued research should be conducted on the characteristics of various strains for a satisfactory preservation of various characteristics.research should be conducted on the characteristics of various strains for a satisfactory preservation of various characteristics.

• Korean Journal of Agricultural Science
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• v.13 no.1
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• pp.17-32
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• 1986

To obtain basic information needed for developing better pearl barley varieties, a total of 148 lines of pearl barley were collected from nationwide survey except for Kangwon and Chejoo provinces and classified by principal component analysis. The results are summarized as follows : 1. Variabilities of characters for all lines except for leaf width and 100 K. Wt.(Unpolished) were high enough to indicate variation of lines. 2. Correlation coefficients among 18 characters were high enough and they showed the shape of normal distribution, more or less, inclined toward positive values. 3. The lines could be classified into four groups by correlation coefficient for 18 characters : Group I was characterized as the lines composed of grain and plant type, Group II maturity, Group III the number of tillers, and Group IV the nature of germination, respectively. 4. About 60% of the total variation could be appreciated by the first four principal components and about 89% of the total variation by the first ten principal components. 5. Contribution of characters to principal components was variable and was high at upper principal components and low at lower principal components. 6. The value of eigen vector corresponding to those which had high significant correlation coefficient between characters was almost of the same value. 7. The lines were classified into four groups by principal component analysis. 8. The lines were also classified into four groups by taxonomic distance. Group I included 79 lines, Group II 40 lines, Group III 22 lines, and Group IV 7 lines, respectively. 9. Four groups classified by taxonomic distance could be characterized as follow : Group I : medium height plant, small kernels, medium maturity, and narrow and short leaf, Group II : short height plant, small kernels, early maturity, and narrow and short leaf. Group III : tall height plant, large kernels, late maturity, and broad and long leaf. Group IV : short height plant, large kernels, medium maturity, and narrow and short leaf.

• Korean Journal of Environment and Ecology
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• v.30 no.1
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• pp.19-38
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• 2016

This study was carried out to investigate the flora, vegetation and soil properties of serpentine area in Andong, Korea. The vascular plants identified during the seven-round field surveys were a total of 359 taxa: 88 families, 239 genera, 311 species, 6 subspecies, 33 varieties, 6 forms and 3 hybrids. 249 taxa were newly discovered in this region. The plant composition of serpentine area is the deciduous broad-leaved and conifer-mixed forest which is the common one in the middle part of the Korean peninsula. Four taxa of Korean endemic plants such as Clematis brachyura, Populus ${\times}$ tomentiglandulosa, Paulownia coreana and Aster koraiensis were collected. The vascular plants on the red list according to IUCN evaluation basis were found to be seven taxa: Near Threatened (NT) species of Hypericum attenuatum, Polygala tenuifolia and Senecio argunensis, Least Concern (LC) species of Penthorum chinense, Potentilla discolor and Acorus calamus, and Not Evaluate (NE) species of Scorzonera austriaca ssp. glabra. The floristic regional indicator plants found in this area were 19 taxa comprising two taxa of grade IV, five taxa of grade III, four taxa of grade II, and nine taxa of grade I. The naturalized plants were identified as 34 taxa and the percentage of naturalized index (NI) was 9.5 %, and urbanization index (UI) was 10.6 %. Forest soils contained high content of nickel and cadmium. The soil layer consists of loam and silt loam from the surface to a depth of 20 cm and loam and silt clay from a depth of 20 cm to 40 cm.

• Korean Journal of Environment and Ecology
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• v.32 no.5
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• pp.445-468
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• 2018

The purpose of this study was to investigate the distribution of vascular plants growing at the Mt. Daedun provincial park area in the boundary between Nonsan-si, Geumsan-gun, Chungcheongnam-do and Wanju-gun, Jeollabuk-do, Korea. We collected the vascular plants 9 times from May 2016 to July 2017. The flora of Mt. Daedun was classified as a total of 434 taxa comprising of 95 families, 278 genera, 388 species, 3 subspecies, 38 varieties and 5 forma. Among them, the endemic plants in Korea that the investigation found were 11 taxa including Broussonetia kazinoki Siebold, Clematis trichotoma Nakai, Thalictrum actaefolium var. brevistylum Nakai, etc. It also found rare plant species, as designated by the Korea Forest Service were 6 taxa including 5 grade LC taxa such as Eranthis stellata Maxim., Viola albida Palib., and Scopolia japonica Maxim. and 1 grade DD taxa, Scrophularia koraiensis Nakai. The special floristic plants were a total of 35 taxa such as 9 taxa in degree III (Eranthis stellata Maxim., Stewartia pseudocamellia Maxim., Acer palmatum Thunb., etc.), 7 taxa in degree II (Equisetum hyemale L., Potentilla dickinsii Franch.&Sav., Viola orientalis (Maxim.) W. Becker, etc.) and 19 taxa in degree I (Dryopteris crassirhizoma Nakai, Cephalotaxus koreana Nakai, Ulmus parvifolia Jacq., etc.) to provide basic data. No taxa in grade V or IV were found. The naturalized plants were 34 taxa including Rumex acetosella L., Phytolacca americana L. and Chenopodium album L., and the percentage of urbanization index was 10.6% while the naturalized plant index was 7.7%.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.2
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• pp.142-149
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• 1995

This study was conducted to investigate the relationships between yearly variation of climatic components and yearly variations of productivity in monoculture cotton. In addition, correlation coefficients among yield and yield components were estimated. The data of yield and yield components from the four varieties(Kinggus, Yongdang local. 113-4, 380) were collected from 1978 to 1992 in Mokpo area. The meteorological data gathered at the Mokpo Weather Station for the same period were used to find out the relationships between climatic components and productivity. Yearly variation of the amount of precipitation and number of stormy days in July are large with coefficients of the variations(C.V)84.89 and 97.05%, respectively, while yearly variation, of the average temperature, maximum temperature, minimum temperature from May to Sep. are relatively small. Seed cotton yield before frost in Sep. and Oct. very greatly with C.V. of 68.77, 78.52%, respectively. Number of boll bearing branches and lint percentage show more or less small in C.V. with 11.77 and 19.13%, respectively and flowering date and boll opening date show still less variation. Correlation coefficients between precipitation in May and number of boll bearing branches, duration of sunshine in July and number of bolls per plant, maximum temperature in July and total seed cotton before the frost in Sep., Oct., and Nov. evaporation in Aug. are positively sig-nificant at the 1% level. There are highly significantly positive correlated relationships among yield(total seed cotton) and yield components. Total seed cotton yield(Y) can be predicted by multiple regression equation with independent variables of climatic factors in July such as monthly averages of average temperature($X_1$), maximum temperature($X_2$) and minimum temperature($X_3$), monthly amount of precipitation ($X_4$), evaporation($X_5$), monthly average of relative humidity($X_6$), monthly hours with sunshine($X_7$) and number of rainy days($X_8$). The equation is estimatedas Y =-1080.8515 + 144.7133$X_1$+15.8722$X_2$ + 164.9367$X_3$ + 0.0802$X_4$ + 0.5932$X_5$ + 11.3373$X_6$ + 3.4683$X_7$- 9.0846$X_8$. Also, total seed cotton yield(Y) can be predicted by the same method with climatic components in Aug., Y =2835.2497 + 57.9134$X_1$ - 46.9055$X_2$ - 41.5886X$_3$ + 1.2559$X_5$ - 21.9687$X_6$ - 3.3763$X_7$- 4.1080$X_8$- 17.5586$X_9$. And the error between observed and theoretical yield were less with approached linear regression.

• Journal of Korean Society of Forest Science
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• v.30 no.1
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• pp.30-41
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• 1976

The workers involved in breeding the growth of forest trees as well as in the efficiency of breeding work wish to find out the evidence that juvenile-mature correlations are high and that therefore early tests can be profitably employed in relation work. Juvenile-mature correlation denotes in general sense the interdependence between qualitative or quantitative data collected at different intervals during the life cycle. The correlation can also be obtained through the stem analysis if there is the possibility of cutting sample trees needed amount. In the present study, the juvenile-mature correlation coefficients are calculated from the stem analysis data. The every possible values of correlation coefficient between the 5-year age groups as to diameter, height, and volume growth of Pinus koraiensis S. et Z. and Larix leptolepis Gord. grown in the middle district of Korea were calculated. All the sample trees were cut from the man made plantation. The correlation coefficients are presented in tables and figures. In Pinus koraiensis S. et Z., the values of correlation coefficient between the successive age groups of heights growth are lower in general than those values pertaining to diameter growth. This tendencies are indifferent to site quality. In Larix leptolepis Gord., the values were lower thant these of Pinus koraiensis S.etZ. In any species and characteristics studied, the implications that at least 15 years growth character are related to 35 or 40 years size with reliability could be deduced. Through the relative ranking studies of diameter, height and volume growth of Larix leptolepis Gord., the large varieties among individual trees are appeared during 5-year to 35 year old.

• Korean Journal of Environmental Biology
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• v.29 no.4
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• pp.296-304
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• 2011

This study was carried out to investigate the relation between water quality and structure of the aquatic ecosystem in the Lake Gachang from February to December in 2010. The annual mean COD (Chemical Oxygen Demand) in Lake Gachang was 3.5 mg $L^{-1}$, indicating, level II of environmental standards and the trophic state was mesotrophic. The seasonal succession of phytoplankton showed that Bacillariophyceae was mostly dominant species throughout the year except August. In case of zooplankton, rotifers dominate in the most seasons, but copepod (Nauplii) in August. The macrophyte plants showed diverse species composition consisted of 9 varieties, 77 species, 64 genera, 34 families and 24 orders. Surveyed species of macroinvertebrates were classified into 1 phyla, 2 classes, 4 orders, 7 families, 9 species. The macroinvertebrates showed FFG (Functional Feeding Groups) such as GC (Gathering-Collector) and SH (Shedder). A total of 42 species of fish was collected including $Zacco$ $koreanus$ and $Coreoperca$ $herzi$. In this study, we investigated environmental factors including pollutant source, load, water quality and distribution characteristics of biota such as phytoplankton, zooplankton, macrophyte plants, macroinvertebrates, fish.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.4
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• pp.485-495
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• 2020

Melon (Cucumis melo L.), one of the most important fruit crop species, is cultivated worldwide. In this study, a total of 206 melon accessions conserved at the National Agrobiodiversity Center (NAC) in RDA were characterized for nine morphological characteristics according to the NAC descriptor list. In addition, to confirm the genetic composition of each melon accession, genetic profiling was performed using 20 SSR markers. Among the 206 melon accessions, 159 (77.2%) were collected from Asia. The color of fruit flesh and skin were mostly 'white' (56.0%) and 'green' (49%), respectively. Days to female flowering (FD) and maturity (MD) of the accessions ranged from 58 to 72 and 17 to 63, respectively. The fruit length and width of the accessions ranged from 6.0 to 29.3 and 3.6 to 17.2 cm, respectively. The sugar content (SU) ranged from 2.5% to 13.2% with an average of 7.0%. In correlation analysis, SU showed positive and negative correlations with MD and FD, respectively. The accessions were classified into four clusters by cluster analysis. From the results of genetic profiling using 20 SSR markers, three accessions (K189118, K100486, and K190292) were expected to be inbred lines among 206 melon accessions. These results could expand the knowledge of the melon germplasm, providing valuable material for the development of new melon varieties to suit consumer tastes.

• Journal of The Korean Society of Grassland and Forage Science
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• v.22 no.4
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• pp.265-272
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• 2002

Forage breeding laboratory of National Livestock Research Institute, R.D.A. has made interspecific hybrids of Lolium multiflorum $\times$ L. pratensis and intergeneric hybrids of Lolium $\times$ Festuca since 1984, and has collected ecotypes of Italian ryegrass since 1991. Growth characteristics of these hybrids and ecotypes were researched, and then these clone lines were named. Among these clone lines, the several clones that have polen fertility, high cold-tolerance, and similar heading time were used for making synthetics, Naehan 6, 7, 8, 9, with polycrossing method in 1997. Field experiments were carried out to compare the mophological and agronomical characteristics and forage productivity and quality of the synthetics with those of Italian ryegrass varieties, Barmultra and Hwasan 101. in Suwon and Yonchun from 1999 to 2000. Heading time of the synthetics were 22th to 24th May that belong to late-mature types to be similar to that of Barmultra and Hwasan 101 in Suwon. The synthetics were 101 to 106 c3n in plant length, medium or thick in thickness of stem, dark peen in leaf color, broad and long in flag leaf, strong in lodging resistance, and excellent in regrowth. Winter survivals of the synthetics were no different from that of Barmultra or Hwasan 101 in Suwon, but better than that of Barmultra or Hwasan 101 in Yonchun where was -10 to -12$^{\circ}C$ of minimum average air temperature in January or February. Dry matter(DM) yields of the synthetics were similar to DM 8,238kg per ha of Barmultra in Suwon, but in Yonchun, were more 7 to 13% than DM 7,291kg per ha of Barmultra. Forage qualities, IVDMD, ADF, NDF and TDN of the synthetics were lower than those of Hwasan 101, but higher than those of Barmultra.