• Korean Journal of Breeding Science
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• v.40 no.1
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• pp.26-30
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• 2008

Normal soybean seed contains three lipoxygenase isozymes called L-1, L-2, and L-3, respectively, which are responsible for the generation of undesirable grassy-beany flavors. Simple and effective methods for the detection of lipoxygenase isozymes were developed in soybean seeds. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) has been tried in separating these isozymes. It was done effectively on 7.5% separating gel and 4.5% stacking gel. However, no reliable method has been developed specifically for separating L-3, L-13 and L-23. Visual judging methods were based on the bleaching activities of lipoxygenase in contact with methylene blue and ${\beta}$-carotene. Sodium linoleate bleaching method was adopted to determine L-1 and L-2. Carotene bleaching and spectrophotometric methods were used to determine L-3. These systems were very rapid within one minute, furthermore only required a small piece of cotyledon (below 10 mg) and the other part could be used for generation advance after analysis. It was demonstrated that 200 seed samples could be analyzed per day by one laboratory assistant. The combination of visual judging methods and electrophoresis is suitable for breeding programs. It took 6.5 hours for analysis of 100 seed samples by one person.

• Korean Journal of Remote Sensing
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• v.38 no.6_1
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• pp.1101-1107
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• 2022

The leaf temperature is principally regulated by the opening and closing of stomata that is sensitive to various kinds of plant physiological stress. Thus, the analysis of thermal imagery, one of remote sensing technique, will be useful to detect crop physiological condition on smart farm system and phenomics platform. However, there are few case studies using a thermal imaging camera on the agricultural application. In this study, three cases are presented: the effect of lime fertilizer on the rice, the different physiological properties of soybean under shading condition, and the screening of soybean breeds for salinity tolerance characteristic. The leaf temperature measured by thermal imaging camera on the three cases was used effectively to the physiological change and characteristics. However, the thermal imagery analysis requires considering the accuracy of measured temperature and the weather conditions that affects to the leaf temperature.

• Korean Journal of Plant Resources
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• v.35 no.5
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• pp.586-593
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• 2022

Soybean (Glycine max (L.) Merr.) is a high-protein oilseed crop, cultivated worldwide. Soybean seeds are abundant in various secondary metabolites with physiologically active. Mature seeds of 25 soybean cultivars with various morphological and physiological characteristics analyzed for secondary metabolites, such as carotenoid, isoflavone, and soyasaponin. These secondary metabolites showed various content by genotype in 25 cultivars. Total carotenoid content ranged from 1.23 to 33.78 mg/g and three cultivars, such as IT177645, PI90763 and IT234975 with black seed coat showed high levels of total carotenoid. Total isoflavones content ranged from 20.28 to 276.35 mg/100g and were detected high levels in Savoy, PI90763 and KLG16001. In addition, total soyasaponins content ranged from 33.12 to 246 mg/100g and were detected high levels in PI90763, PI86490 and IT234975. The PI90763 was showed abundant content in all of the carotenoid, isoflavones and soyasaponins. These results could be valuable information for the development of new soybean cultivars and regulation of secondary metabolites biosynthesis in soybean.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.6
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• pp.528-533
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• 1992

Soybean seeds contain lipoxygenase, which is responsible for the objectionable beany flavors in soybean seeds. The isozymes of lipoxygenase (1$\times$1, 1$\times$2, 1$\times$3) were discovered in United States of America, Japan, and Korea, and the mode of inheritance of the mutant genes was determined. This investigation was conducted to screen lipoxygenase-1, 2, and 3 lacking soybean lines from the Korean soybean land race population. Two lipoxygenase-1lacking lines, KAS 610-8 and KAS 621-8 were found in this investigation. In general, lipoxygenase acking varieties were small in seed size and low in oil content. A severe pod borer damage was observed in the two selected lipoxygenase-1 lacking lines. Lipoxygenase lacking line was not found in Korean wild soybean population used in this study and the lipoxygenase lacking lines were found only in Kyung-Nam province and the results imply that lipoxygenase lacking mutants were induced recently in cultivars.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.4
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• pp.452-458
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• 1997

Seed characteristics such as seed size, seed shape and cotyledon color are important in relation to processing and cooking of soybean. Seed shape, water absorption rate, and alkali digestibility were evaluated for 28 local black soybean collections. Water uptake rate was low in small seed size at low temperature(5, 2$0^{\circ}C$). However, higher water absorption rate was observed at high temperature(40, 6$0^{\circ}C$) regardless of seed size. When seeds soaked up water, it reached to water absorption equilibrium after 10 hrs below 2$0^{\circ}C$, within 10 hrs at 4$0^{\circ}C$, and around 4 hrs at 6$0^{\circ}C$, respectively. Significant positive correlations were observed between 100 seed weight and length, width and thickness of seed, respectively. Alkali digestibility value(ADV) was higher in large seed group than in small seed group. Among seed characteristics, significant positive correlation was shown between ADV and 100 seed weight, length, width, thickness and hilum length of seed, respectively. Soybean seed with green cotyledon showed higher ADV than that with yellow cotyledon.

• Korean Journal of Soil Science and Fertilizer
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• v.32 no.2
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• pp.164-170
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• 1999

This experiment was carried out to elucidate change of antioxidant enzymes activities subjected to water stresses in soybean plant. In this study, we measured the activities of ascorbate peroxidase(APDX), monodehydroascorbate reductase(MDHAR), dehydroascorbate reductase (DHAR), glutathione reductase(GR) subjected to drought or flooding stresses for 4days and following recovery for 3days. Leaves of two soybean lines subjected to drought or flooding showed premature senescence as evidenced by the decrease in water content and total soluble protein content but those of soybean leaves was increased when stresses were recovered for 3days. The activities of APDX and GR subjected to drought or flooding were the decrease but those of enzymes were recovered when water stress was recovered. The activities of MDHAR with drought or flooding were on the decrease, whereas those of DHAR were increased, respectively. Antioxidant contents decreased continually subjected to drought or flooding but it recovered after 3 days subjected to water stresses.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.29 no.3
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• pp.280-284
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• 1984

Association of SMV infection in soybean plants with seedcoat mottling and with seed transmission of SMV was examined. Seedcoat mottling was increased positively in proportion to the SMV severity in variety Clark. No correlation was found between the incidence of mottled seed and the seed's position on the plant. Susceptible variety with virus symptoms gave rise to mottled seeds but only a small percentage of these mottled seeds could transmit the virus. SMV could be transmitted even by nonmottled seeds harvested from SMV infected plants in similar rate with mottled seed. It seemed that the amount of mottled seed could be used as an indicator of the amounts of SMV infection in a seed production field.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.3
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• pp.257-265
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• 1996

To obtain the basic informations necessary to develop the production technology of vegetable soybean seeds, this study was conducted at the National Crop Experiment Station, RDA, Suwon, Korea in 1993. Seeds of three vegetable soybean varieties, 'Mikawashima', 'Hwaeomputkong', and 'Seokryangputkong' produced at Pyeongchang, a highland in Korea and introduced from Japan were planted on April 20 in the field. The emergence rate among varieties was significanlty different. Emergence rate of seeds produced at Pyeongchang was higher by 7% than that of the seeds from Japan. Rate of pod infection by Phamapsis spp., brown spot by Septaria glycines, soybean mosaic virus(SMV), and downy mildew by Peronospora manshurica in the field was not different between locations. The growth characteristics, yield components, and green pod and grain yields were not different between locations. Therefore, it was proved that the production of vegetable soybean seeds with the better quality and higher emergence is possible in highland, Korea. possible in highland, Korea.

• Korean Journal of Weed Science
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• v.2 no.2
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• pp.75-113
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• 1982

Studies were carried out 1) to define the shape and size of sampling quadrat and its number of observations for weed experiments, 2) to characterize the growth and community of major summer weeds under upland condition and 3) to investigate the factors influencing competition between weeds and soybeans under weed-free and weedy conditions in early and late season cultures. No significant difference was noted among different shapes of quadrat (regular, rectangular, band, and circular) in the sampling efficiency of weeds. The results also suggested that the minimum size of quadrat was 0.25$m^2$ and the minimum number of replication was 2 times per plot. The major dominant weeds were about 10 species in the experimental field and the total number of weeds was in the range of 70 - 1,600 plants per $m^2$. Among the weeds Digitaria sanguinalis and Portulaca oleracea were the most dominant species. Growth amount and reproduction capability were also measured by weed species. Five different weed communities were identified in the field. The degree of dispersion by weed species and association among weeds were investigated. Intra-(within soybeans) and inter-specific (between soybeans and weeds) competition were studied in early and late season cultures of soybeans. The average yield of soybeans per plant was significantly decreased in both season cultures due to intra-specific competition as the planting density of soybeans increased, On the other hand, the average yield of soybeans per l0a was proportionally increased to the increase of planting density and the rate of its increase was more significant under weedy than weed-free condition. Most of the agronomic characteristics of soybeans were affected by weeds and its degree was greater in sparse planting than in dense planting and in early season than in late-season culture. Digitaria sanguinalis was the most competitive to soybeans in early season and both of Digitaria sanguinalis and Portulaca oleracea affected primarily the growth of soybeans in late season with about the same competitiveness. The occurrence of weeds was significantly decreased in early season and slightly decreased in late-season by dense planting of soybeans. The total growth amount of weeds was also considerably decreased by increase of soybean planting density both in early- and late-season cultures. The occurrence of Digitaria sanguinalis which was the most dominant in both seasons, and its growth amount was significantly decreased as the planting density of soybean was increased. On the other hand, the occurrence of Portulaca oleracea which was only dominant in late-season culture did not show significant response to the planting density of soybeans.

• 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.