• Korean Journal of Plant Resources
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• v.18 no.1
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• pp.148-153
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• 2005

With the increase in the level of national income, the interest and demand of the wild edible plants have been increased. Aralia elata Seem is highlighted as a new income source for farmers in Korea. This study was conducted to determine the optimum planting density enhancing the commercial yield and quality in Aralia elata Seem. Yield of new shoots per 10a was increased in the dense planting of $1m\times30cm$ by three years of planting, but it was decreased after four years of planting, which was mainly caused by the factors such as high mortality rate. The income per 10a in the planting density of $1m\times50cm$(2,000 plants/10a) was higher by $27\%$ than that in the planting density of $1m\times30cm$(3,300 plants/10a) which was 968,00won per 10a.

• Korean Journal of Plant Tissue Culture
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• v.27 no.3
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• pp.213-217
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• 2000

To investigate the cucumber regeneration from embryogenic calli, shoot tips of aseptically-grown cucumber seedlings were used as explants for establishing tissue cultures. Growth and differentiation of callus were studied by using Murashige and Skoog's (MS) medium containing 0.5 to 2 mg/L 2,4-D. Plantlets were induced from shoot tip culture on the plant growth regulators-free MS medium. Non-embryogenic calli and viscous calli were induced on the medium supplemented with 0.5 to 2 mg/L 2,4-D, but embryogenic callus was not induced on the same medium. Segments (ca. 5∼10 mm) of aseptically-grown hypocotyl from five to seven days old seedlings after germination were placed on MS medium supplemented with 1 mg/L 2,4-D for 50 days. Embryogenic calli and embryoids were induced only from the seedlings grown in dark condition, and hypocotyl was placed on the media explanted in light condition. Foully-five point one percent of white fragile calli and 0.6% yellowish compact calli formed roots. Yellowish callus lines were investigated to have a considerably higher concentration of crude proteins than white callus lines. Plantlets derived from embryogenic calli or embryoids have been transferred to pots containing sterile vermiculite and perlite. Normal fruits were harvested from nutrient culture on aggregated hydroponics in the F-clean house.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.34 no.4
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• pp.400-407
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• 1989

This experiment was carried out to study the effects of nitrogen concentration of cultural solution, Rhizobium inoculation, and planting density on the growth and yield of soybean cultivars, Hwanggeumkong, Jangbaegkong, Paldalkong, Clark, and non-nodulation isoline of Clark. Rhizobium inoculation increased the stem length, particularly in Hwanggeumkong, Jangbaegkong, and decreased it significantly in non-nodulation Clark. Stem length was increased by the increase in nitrogen fertilization by the 195ppm level and decreased by the increase in plant population density. Rhizobium inoculation also increased the shoot dry weight, but significantly decreased it in non-nodulation Clark. As nitrogen concentration in the cultural solution increased the shoot dry weight decreased in Jangbaegkong and paldalkong. However, the shoot dry weight was decreased by the increase in plant population density. Rhizobium inoculation and the increase in nitrogen concentration of cultural solution increased the ratio of shoot dry weight to root weight. The Rhizobium inoculation and the increase in nitrogen concentration of cultural solution increased the grain yield per pot in Hwanggeumkong and paldolkong, While non-nodulating Clark showed significant decrease in grain yield. Grain yield per pot was also increased by the increase of plant population density. Grain yield was significantly correlated with shoot dry weight, nodule number, and nitrogen content of the soybean plants. The correlation between nitrogen contents of the soybean plants and stem length, shoot dry weight, and nodulation was significant. The allantoin-N content in stem was also significantly correlated with nodulation.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.17
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• pp.45-78
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• 1974

To provide useful information for developing new high yielding soybean varieties and for improving cultural practices, an investigation was made on variation of dry matter production and on relationship among several agronomic characters of soybean plants grown under different planting times and densities as well as under different fertilizer levels, using Kwang-kyo, Dong puk-tae, and Suke ＃ 51 as determinate types and Shelby, SRF-300 and Harosoy as indeterminate types at the Crop Experiment Station during the period of 1972 and 1973. The results obtained were summarized as follow: 1. The dry weight, CGR and LAI at the initial flowering stage were high in the high plant population irrespective of varieties, planting times, and fertilizer levels. However, those characters of the indeterminate type were lower than those of the determinate types. The same characters of the indererminate type at the terminal leaf stage were either same or higher than those of the determinate types. 2. The dry weight of the determinate type at the initial flowering stage was similar to the indeterminate, type, when planting times were May 21 or June 15. The dry weights of both types of varieties were low when planted on July 10. When fertilizer levels were increased, the CGR, dry weight and LAI at the initial flowering stages were also increased. 3. Even though significant differences of LAI were obtained among the varieties within the same plant type, the indeterminate type was in general lower than that of the determinate type regardless of planting time and densities, or fertilizer levels, while the yield of the indeterminate type was comparable to the yield of the determinate type. 4. The high degree of leaf- and petiole-fall at the greenbean stage was highly associated with early planting and high levels of fertilizers. However, less amount of leaf- or petiole-fall was found when planted on July 10 or under low plant population. 5. The percent of stem weight was high under higher plant population, while the percent of leaf weight was high under lower plant population. When planting time was late, the percent of stem and petiole weight were reduced, while the leaf weight was increased. 6. The percent of pod weight of the determinate type at the terminal leaf stage was about 2% when planted on May 21, about 8% when planted on June 15, and about 9% when planted on July 10. The percent of pod weight of the indeterminate type at the terminal leaf stage were about 6 % when planted on May 21, 14% when planted on June 15 and 21% when planted on July 10. 7. Kwang kyo showed less degree of leaf-fall even when lodged due to high levels of fertilizer applied, while SRF-300 showed great damage due to lodging. 8. High yields were obtained when planted on May 21, but there were little yield differences between yields from May 21 and June 15 plantings. The reduction of yield due to late planting of July 10 was less apparent in the determinate type of varieties, while it was high in the indeterminate type. 9. The optimum plant population per are for high yield was 1, 250 to 2, 500 plants when planted on May 21, 2, 500 plants when planted on June 15, and 3, 333 plants when planted on July 10. 10. High correlation coefficients were obtained between dry matter weight and LAI at the terminal leaf stages, and between the dry matter weight and yield at the greenbean stages. The optimum dry weight for high yield in the determinate type was expected to be 25 kg. per are at the initial flowering stage and 50 kg. per are at the terminal leaf stage. In the indeterminate type the LAI and dry weight at the greenbean stage were 4 to 5 and 80 kg. per are, respectively. 11. Under the high plant population plant height was increased, while the stem diameter and the number of nodes and branches were reduced. Consequently, the percent of mainstem to main stem plus branches were increased, and the length of internode was also elongated. The ratios of stem weight, number of nodes and pods, and yield of main stem were increased when high plant population was associated with the early planting. The percent of main stem to branches for the indeterminate type was higher than that of the determinate type. 12. Under the high plant densities and late planting, the percent of the pod number and yields of main stem were increased, indicating that varieties with no or less branches were better adaptable under such conditions. 13. High degree of simple correlation coefficients was obtained between the LAI at the initial flowering stage and terminal leaf stage, and the total node number, dry matter and dry stem weight of both determinate and indeterminate types. Even though no significant correlation was found between the LAI at the initial flowering stage of the determinate type and the stem length and pod number per are, highly significant correlation coefficients were obtained between such characters in the indeterminate type of varieties. 14. The dry matter was positively correlated with the LAI, CGR, stem length, and pod number, node number and dry stem weight per are, while no significant correlation was found between the dry matter and stem diameter. 15. The correlation coefficients between lodging index and the LAI, dry weight, stem length and dry stem weight were highly significant. Negative correlation was obtained for the indeterminate type between the stem diameter and lodging index. The correlation coefficient between the stem diameter and lodging index was non-significant for the determinate type, while positive correlation was obtained between the yield and lodging index in the determinate type. The lodging index was also positively correlated with average length of internode of main stem. 16. The 100 seed weight appeared to be lowered under the high plant population and no fertilizer condition, and when planted late. Apparent differences of 100 seed weight were found between main stem and branches, being higher for the main stem than for the branches. 17. No variation of protein content was found due to different cultural practices. However, the oil content was apparently reduced when planted late.

• Korean Journal of Soil Science and Fertilizer
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• v.17 no.2
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• pp.108-113
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• 1984

To find out the differences in micro-meteorological changes in the rice plant canopy at the different growing stages, Seokwang-byo, a high yielding variety, was cultivated with three planting densities of 50, 80 and 110 hills per $3.3m^2$ in 1982, and Seokwangbyo and Chucheong-byo, a local variety, were planted with a density of 80 hills per $3.3m^2$. Air temperature in plant canopies, water and soil temperatures were continuously monitored throughout the growing period. The relationship between solar radiation interception and leaf area indices at different height in the canopy also was studied. The results were as follows: 1. Air temperature in the densely planted canopy was 1 to $1.5^{\circ}C$ higher than that in the sparsely planted one at the early growing stage, but was inverted after 60 days of transplanting. The vertical distribution of temperature in the canopies showed that air temperature at 10 cm height from the ground was higher than that at 30 cm height. The temperature inversion occurred showing lower temperature at the 10 cm height than at the 30 cm height. 2. The highest temperature of a day in the canopy occurred at 14:00 to 15:00 Korean Standard Time same as that of air temperature, but approached to the solar noon time as the plants grew thick. 3. The air temperature in the canopy became higher than water temperature when the leaf area indices were 4.6 for Chucheongbyo and 5.2 for Seokwangbyo, and the light penetration ratios were 40 percents. 4. Light extinction coefficients of the 50 to 70 cm layer of the canopies were 0.3 to 0.5 but decreased at the lower layers. 5. Albedo of the canopies was 0.4 in the morning and evening while that was about 0.25 at noon. The difference in albedo between Seokwangbyo and Chucheongbyo could be recognized with the difference in leaf structure.

• Korean Journal of Agricultural Science
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• v.4 no.2
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• pp.283-316
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• 1977

In an attempt to obtain a basic information to develop an effective integrated system of controlling sheath blight of rice in Korea, the transition of this disease, the variation of cultural characters and pathogenicity of the pathogen, environmental conditions affecting the disease outbreak and varietal resistance have been investigated. 1. Rice sheath blight which has been minor disease in the past was widely spread, especially since 1971. This disease has promptly spread all over the country and infected 65.2% of total rice growing area in 1976. Various factors are considered to be related to such transition of this disease. Above all, increace of application of nitrogenous fertilizer, early season and earlier cultivation of rice, introduction of more susceptible "Tongil" varieties etc. must be important factors influencing the outbreak of this disease. 2. Great variations in cultural characteristics-such as mycelial growth rate, color of the medium, amount of the aerial mycelium, shape and color of the sclerotia- and in the pathogenicity of isolates of the pathogen, Thanatephorus cucumeris Dank were observed. The optimum temperature for mycelial growth also varied with isolates, from $25^{\circ}C$ to $30^{\circ}C$. There were not necessarily any correlation between curtural characteristics and pathogenicity of isolates of Thanatephorus cucumens. 3. Mycelial grow th of isolates of Thanatephorus cucumens on the PDA medium were correlated with the air temperatures of the region where the isolates were collected. The isolates from the regions with high temperature grew well on PDA medium at $35^{\circ}C$ than those from the region with low temperature, on the other hand, the isolates from the regions with the low temperature grew well on the same medium at $12^{\circ}C$ than those from the regions with high temperature. 4. Pectin polygalacturonase (PG) and cellulase (Cx) were most active on the 3rd day after inoculation on the leaves of rice plant with Thanatephorus cucumeris, whereas pectin methylestrase (PE) was most active on the 4th day after inoculation. Relationship between the activities of PE of isolates and the strength of pathogenicity of isolates was obtained, but PG and cellulase activities were not correlated with pathogenicity of isolates. 5. The tolerence of sclerotia from in-vitro culture to low temperature varied with their water content, the dried cultural sclerotia were more tolerent than wet ones, Dried cultural sclerotia maintained almost 100% germinability for 45 days at $-20^{\circ}C$, whereas wet sclerotia lost viability at $-5^{\circ}C$. The germination ratio of the sclerotia after overwintering changed from 18% to 70% according to the water content of the test paddy fields and the ratio was low in wet paddy condition. 6. To investigate the host range of this fungi in and near paddy field, 17 weeds were inoculated with fungi. The lesions of sheath blight disease was obserbed on Sagittaria trifolia L., Echinochloa crusgalli P. Beauv., Monochoria vaginal is Presl, Polygonum Hydropiper L., Eclipta prostrata L., Digitaria sanguinalis Scapoli. 7. When the level of nitrogen applied was doubled over standard level, total nitrogen content in rice sheath increased, ami when silicate was applied, starch content in rice sheath decreased, inducing the rice plants more susceptible to sheath blight disease. Increased dressing of potash ferilizer reduced the incidence of sheat blight disease. 8. The percentage of infected stems in the early period increased more in the narrow hill plot than in the wide hill plot, but in the late period this tendency was inversed; the percentage of infected stems as well as severity in the wide hill plot increased more compared to the narrow hill plot, and the disease severity in the one plant per hill plot was also low. The number of stems in the wide hill plot was more than the number of stems in the narrow hill plot. This indicates that the microclimate, such as the relative humidity, in the narrow hill plot was more favorable for the development of this disease. 9. There was a high negative correlation between the disease severity of varieties to the sheath blight and the maturity of the varieties, that is, the early varieties were more susceptible than the late ones, and much-tillering varieties usually showed more infection than less tillering varieties. 10. No relationship was obtained between the percentage of infected stems in the early period and the severity after heading, whereas a distinct relationship was obtained between former and latter after Aug. 10.

• Korean Journal of Medicinal Crop Science
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• v.5 no.2
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• pp.95-101
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• 1997

This study was conducted to investigate how a labor saving for conventional hand sowing and respond to major agronomic traits under different planting density in 1993 and 1994. Each trial was a randomized block split plot with row spacing as the main plots and hill spacing as subplots. Sowing rate appeared lower in 20 or 25cm hill spacing using machine seeder than in hand sowing. Sowing time required reduced more 121 hours per hectare in 60cm row, 20cm hill spacings using machine seeder than in hand sowing. Increasing row and hill spacings reduced number of seedling stand per unit $area(m^2)$. Both number of pods per plant and grain weight per plant and showed highly increase in wide planting. Best yield obtained in 60cm row, 20cm hill spacing using machine seeder. Accumulative mean air temperature was positively correlated with stem height, number of pods per plant and yield, otherwise accumulative rainfall was negatively correlated with ones. A highly significant negative correlation was showed between number of seedling stand per unit $area(m^2)$ and number of branches, number of pods per plant, grain weight per plant and yield. Yield was positively correlated with number of branches, number of pods per plant and grain weight per plant.

• Journal of Plant Biotechnology
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• v.50
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• pp.155-162
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• 2023

Radish (Raphanus sativus L.), a root vegetable grown worldwide, is consumed in several ways. In the cross between parental lines to produce F1 seeds of radish, the problem of low purity may arise because of pollen contamination. Therefore, we aimed to establish conditions for callus induction and regeneration so that in vitro cultured plants could be used for the propagation of stock seeds. The most effective hormone combination containing various concentrations of 2,4-D, TDZ, and kinetin was selected for callus induction using radish hypocotyl, and the induced calli were transferred to two types of hormone media to investigate the optimal conditions for shoot regeneration of the callus. The combination of 1 mg/L 2,4-D + 0.05 mg/L kin was the most effective for callus induction of RA2 and RA10, 1 mg/L 2,4-D + 0.1 mg/L kin + 0.025 mg/L TDZ of RA4, and 1 mg/L 2,4-D + 0.2 mg/L kin of RA30. Shoot regeneration of the RA4 callus occurred in both shoot regeneration media, but the frequency was much higher in the 5H+1B medium (1 mg/L NAA + 0.1 mg/L 2,4-D + 1 mg/L IPA + 0.02 mg/L GA3 + 2 mg/L zeatin + 1 mg/L BA). For the in vitro micropropagation of radish, the conditions selected in this study can assist in the propagation and maintenance of stock seeds to produce F1 seeds.

• 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.