• Applied Biological Chemistry
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• v.40 no.5
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• pp.438-441
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• 1997

The relatedness of naturalized Bradyhizobium japonitum populations with soil physico-chemical characteristics as affected by paddy rice-upland soybean rotation cropping with conventional and none fertilization in Chilgog clay loam soils were determined as follows. The populations of B. japonicum in soils were increased from about $10^1$ in continuous paddy upto $10^1cells/g.soil$ only in one-year rotation of upland use with soybean cropping. Compared to the densities in plots of conventional fertilization, those in none fertilization were high ranging from 1.9 to 10 fold in 2-year upland use rotation and both in 3-year upland use rotation and 4-year upland use, respectively. The populations were positively correlated with soil organic matter $contents(r=0.83^*),\;Ca/K(r=0.74^*),\;and(Ca+Mg)/K(r=0.72^*)$ and were negatively correlated with soil $hardness(r=-0.73^*)$. And the soil populations increased by paddy-upland rotation resulted in superior symbiotic potentials to those in continuous paddy use in terms of nodule mass, nitrogenase activity, and soy-bean shoot dry weight.

• Magazine of the Korean Society of Agricultural Engineers
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• v.35 no.3
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• pp.36-46
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• 1993

The purposes of this study are to develop three-layered Green-Ampt infiltration model considering temporal variation of physical properties of soil and to evaluate the model with field experiment on bare-tilled and soybean-growing soil plots under natural rainfalls. Infiltration tests were conducted on a sandy loam soil. The model has three-layered soil profile including a surface crust, a tilled layer, a subsoil and considers temporal variation of porosity, hydraulic conductivity, capillary pressure head on a tilled layer by natural rainfalls and canopy density variation of crop. Field measurement of porosity, average hydraulic conductivity and average capillary presure head on a tilled layer were conducted by soil sampler and air-entry permeameter at regular intervals-after tillage. It was found that temporal variation of porosity and average hydraulic conductivity might be expressed as a function of cumulative rainfall energy and average capillary pressure head might be expressed as a function of porosity of a tilled soil. The model was calibrated by an optimization technique, Hooke and Jeeves method using hourly surface runoff data. With the calibrated parameters, the model was verified satisfactorily.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.1
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• pp.7-11
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• 2004

Alfalfa (Medicago sativa L.) plants have been reported to be autotoxic as well as allelopathic. Laboratory and greenhouse experiments through petri-dish and pot test were conducted to determine autotoxic effects of alfalfa leaf and soil extracts on the germination or early seedling growth of alfalfa, and to evaluate allelopathic effects of alfalfa leaf residues on alfalfa, barnyard grass, com, eclipta and soybean. Alfalfa seed germination was delayed depending on aqueous extract concentration, with no difference in final germination after 48 hours. Alfalfa root length was more sensitive to the autotoxic chemicals from leaf extracts than was germination or shoot length. Root growth of alfalfa was significantly inhibited at extract concentration of more than 1 g dry tissue/L (g $\textrm{L}^{-1}$). Hypocotyl growth, however, was not affected by all the concentrations of leaf extracts. Soil extracts from 4-yr-old alfalfa stand significantly reduced alfalfa root length by 66%, while soil extracts from 0,1, and 3yr-old stand stimulated root length up to 14-32% over the control. Residue incorporation with dry matters of alfalfa leaf at 100 g $\textrm{kg}^{-1}$ reduced seedling length of several crop and weed species, ranging from 53 to 87% inhibition. Addition of nutrient solution into alfalfa leaf extracts alleviated alfalfa autotoxic effect. This result indicates alfalfa leaf and soil extracts or residues could exert autotoxic as well as allelopathic substances into soil environments during and after establishment.

• Journal of Life Science
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• v.8 no.5
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• pp.557-562
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• 1998

This study was conducted to investigate the influence of soil moisture on the photosynthetic rate, transpiration rate, stomatal conductance, leaf water content and its any correlation in soybean. Followings were achieved as a conclusion. At the soil moisture was moved from drought condition to saturation condition, the photosynthetic rate, transpiration rate, stomatal conductance and leaf water content were gradually increased on the period of re-watering treatment. The recovery of photosynthetic rate was faster than others. There were positive correlation with the photosynthetic rate and leaf water content, the stomatal conductance and leaf water content, the photosynthetic rate and stomatal conductance respectively, but the correlation coefficient of photosynthetic rate and leaf water content was high.

• Korean journal of applied entomology
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• v.9 no.1
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• pp.21-24
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• 1970

Effect of seed disinfectants for controlling the soybean anthracnose was investigated with percent of seedling infection to seed or soil and with inhibition zone on potato dextrose agar. The chemicals tested were as follows: Arasan, Orthocide, Phygon-XL, P.T.A.B. and Mercuron. In seed inoculation, all the chemicals used resulted in significantly less seedling infection than that obtained in control. In the case of soil infection, the result was similar to the above but percentages of the infection were lower than the seed inoculation. Percentages of seedling infection were not necessarily correlated to the inhibition zones on potato dextrose agar by the same chemicals.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.32 no.3
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• pp.268-276
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• 1987

Five soybean varieties were used to measure seed vigor according to the artificially different deterioration. A vigor index derived from the product of percent germination x hypocotyllength was used as the parameter in comparison of other tests for seed vigor. There were the varietal differences in initial vigor. The warm germination test was the best measurement for seed vigor at the advanced stages of seed deterioration. All other vigor measurements, except ATP and GADA measurements, showed highly significant correlations with the vigor index. Hypocotyl length, conductivity index and cold germination measurements for seed vigor were appropriate for predicting seed quality.

• Journal of The Korean Society of Grassland and Forage Science
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• v.17 no.2
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• pp.167-176
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• 1997

A field experiment was conducted in Chungiu and Jungwon to evaluate growth characteristics, root development, dry matter yield, crude protein yield and palatability according to nitrogen fertilizer level at intercropping cultivation of sorghum $\times$ sudangrass hybrid(hereinafier referred as SSH) and soybean. Nitrogen level was six treatment of Okg, 30kg 60kg, 90kg 120kg, and 150kg per hectare, and cutting date (sorghum $\times$ sudangrass and soybean) was july 28. 1. In the SSH, plant length was increased with increasing nitrogen fertilizer from 0kg/ha to 120kg/ha, but 150kgha treatment was decreased cornpared to 120kg/ha treatment. In the soybean, plant length did not show difference among 0kg, 30kg 60kg, and 90kg per hectare, but 120kg and 150kgfha treatment was on the contrary short. In the SSH, leaf length, leaf width and leaf number were the highest in 120kg/ha treatment, but soybean showed multifarious. 2. Stem diameter of SSH was increased with increasing nitrogen fertilizer. But soybean was thick from 0kg/ha treatment to 60kg/ha treatment, while above 90kg/ha treatment was on the contrary thin. Stem of SSH was hard with increasing nitrogen fertilizer, but soybean was soft with increasing nitrogen fertilizer. Root weight (Dry matter) of SSH was increased with increasing nitrogen fertilizer. On the contrary, soybean was decreased with increasing nitrogen fertilizer. 3. In the dairy cattle and Korean native cattle, palatability according to nitrogen fertilizer was the highest at 90kgha treatment, while 120kgha treatment and 150kgha treatment was the lowest. But in the deer, 30kg/ha treatment of low nitrogen fertilizer was the highest in palatability. 4. Nitrogen content of root of SSH was increased with increasing nitrogen fertilizer(P<0.01). But in soybean, 30kg and 60kg/ha treatment were higher than 0kg, 90kg, 120kg and 150kg/ha treatment(P<0.01). Total niwogen content of soil were high at 90kg 120kg 150kgha trea~ment(P<0.01). 5. Dry matter yield was high at the 90kg 120kg and 150kgha treatment as range from 15, 262kg/ha to 15, 614kg/ha without significant difference among those, but Okgha treatment was the lowest as 11, 183kg/ha (PC 0.05). Protein content of SSH was the highest at 90kg/ha treatment as 8.3 percentage. Soybean was highest at 60kgha treatment as 22.9 percentage. Protein yield was the highest at 90kg/ha treatment as 1, 547.6kg/ha, but Okgha treatment was the lowest as 1, 022.8kg/ha (P<0.01).

• Journal of Crop Science and Biotechnology
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• v.11 no.2
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• pp.91-100
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• 2008

Melting curve analysis of fluorescently labeled DNA fragments is used extensively for genotyping single nucleotide polymorphism(SNP). Here, we evaluated a SNP genotyping method by melting curve analysis with the two probe chemistries in a 384-well plate format on a Roche LightCycler 480. The HybProbe chemistry is based on the fluorescence resonance energy transfer(FRET) and the SimpleProbe chemistry uses a terminal self-quenching fluorophore. We evaluated FRET HybProbes and SimpleProbes for two SNP sites closely linked to two quantitative trait loci(QTL) for southern root-knot nematode resistance. These probes were used to genotype the two parents and 94 $F_2$ plants from the cross of PI 96354$\times$Bossier. The SNP genotypes of all samples determined by the LightCycler software agreed with previously determined SSR genotypes and the SNP genotypes determined on a Luminex 100 flow cytometry instrument. Multiplexed HybProbes for the two SNPs showed a 98.4% success rate and 100% concordance between repeats two of the same 96 DNA samples. Also, we developed a HybProbe assay for the Rcs3 gene conditioning broad resistance to the frogeye leaf spot(FLS) disease. The LightCycler 480 provides rapid PCR on 384-well plate and allows simultaneous amplification and analysis in approximately 2 hours without any additional steps after amplification. This allowed for a reduction of the potential contamination of PCR products, simplicity, and enablement of a streamlined workflow. The melting curve analysis on the LightCycler 480 provided high-throughput and rapid SNP genotyping and appears highly effective for marker-assisted selection in soybean.

• Korean Journal of Soil Science and Fertilizer
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• v.12 no.1
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• pp.43-46
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• 1979

Curing the studies on the mechanism of the nodule formation and the infection of rhizobia using the continously cultured plant cell tissues, it was found that some calluses possess high nitrogen fixation activity. This experiment was conducted to know the differences among the calluses and the Rhizobia. The results obtained were as follows; 1) In a single inoculation the nitrogenase activity of soybean cell cultures-rhizobium was moderately higher than non-leguminous cell cultures, however, in the mixing inoculation that was reversely found. 2) Host factor, which was characteristics for the nodule formation and the nitrogenase activity, was not appeared generally in the plant cell cultures except for Kuamusume and Toyozuzu in soybean, and Datura in non-leguminous cell cultures. 3) In the 012 rhizoblium cultured on soybean cell cultures and in the 010, 023 and 024 rhizobia cultured on non-leguminous cell cultures the nitrogenase activity higher than the others.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.33 no.3
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• pp.254-261
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• 1988

Lysimeter and field experiments were conducted in Sandy Loam to establish a simple estimation model for evapotranspiration (ET) of soybean for three years (l984-1986). Potential ET (PET) could be estimated by the eq.1 using Pan-evaporation (Eo) and was ranged from 1.1 to 4.6 mm/day during the experiments. PET (mm/day)=1.348＋0.573 Eo …(1) Crop coefficient (Kc=maximum ET/PET) could be estimated by the eq.2 using Growth degree (G=days after planting/total growing days) and was ranged from 0.2 to 1.1 and from 0.6 to 1.4 for monoculture cropping and double cropping followed by barley, respectively, during the experiments. Monoculture : Kc=0.016＋3.719 G-3.224 G$^2$…(2), Double cropping : Kc=0.609＋2.014 G-2.120 G$^2$…(2). However, the maximum Kc was shown when G was about 50% and 40% for the monoculture and the double cropping, respectively. Soil water coefficient (f=AET/maximum ET) could be estimated by the eq.3 using soil water tension (Ψ) in 15cm depth. and it was decleased to 0.2 when Ψ was 10 bar. f=0.755-0.537 log │Ψ│…(3) Consequentially, the model to estimate the Actual ET (AET) of soybean was determined as eq.4 with the correction coefficient of -0.380. AET(mm/day)=PETㆍKcㆍf -0.380 …(4) The estimated AET were compared with the measured AET to verify the model established above. The average deviation of the estimated ET(AET) was 0.5782$\pm$0.338 (mm/day), and it would be within reasonable confidence range.