• Korean Journal of Medicinal Crop Science
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• v.28 no.4
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• pp.298-309
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• 2020

Background: Safflower (Carthamus tinctorius L.) is a useful medicinal and oil crop in Korea. However, when safflower is cultivated, the flowering period overlaps with the rainy season, and seed maturation is poor. Therefore, this study aimed to use basic research data to develop superior varieties using agronomic characteristics and crossing method. Methods and Results: A total of 34 safflower germplasms were sown and their agronomic characteristics were investigated. Based on these investigations, the cultivar 'ui-san-hong-hwa' was selected as the mother plant, and 'Myanmar safflower' (Hsu Pan) was selected as the father plant. In addition, we developed a floret-protecting cap to cover florets after emasculation during the artificial crossing. When florets were protected by the cap, the seed setting rate increased in comparison to that in the non-covered florets. Conclusions: Agronomic characteristics can contribute to developing suitable varieties. The results suggest that the protection cap will be helpful in breeding without the floral organ drying. This study contributes an efficient breeding method to develop new safflower varieties.

• Journal of the Korea Concrete Institute
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• v.27 no.3
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• pp.265-272
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• 2015

In this study, a method to reduce temperature rise due to hydration in mass concrete is investigated. It is to use retarder (glucose) for reducing heat of hydration and to use calcium silicate hydrate (C-S-H) for compensating the retardation effect due to its role as a nucleation seed. For this purpose, the temperature rise of cement paste due to hydration was measured and the effect of using both C-S-H and glucose on setting and 28-day compressive strength of mortar specimens was investigated. According to the experimental results, using C-S-H and glucose caused the reduction in the maximum temperature but accelerated the time to reach the maximum temperature compared to that of retarded cement paste using glucose. In addition, using C-S-H and glucose did not show significant effect on 28-day compressive strength of mortar specimens, indicating that the method shown in this study can be a successful alternative to control maximum temperature rise in mass concrete.

• Plant Resources
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• v.5 no.3
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• pp.196-201
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• 2002

This study was conducted to investigate the relationships between yearly variations of climatic elements and yearly variations of productivity in sesame. In addition, correlation coefficients among yield and yield components were estimated. The data of yield and yield components were investigated for 10 years from 1992 to 2001. The meteorological data gathered at the Yeosu Weather Station for the same period were used to find out the relationships between climatic elements and productivity. Yearly variation of the amount of precipitation in July and September were large with coefficients of variation(c.v.) of 64.59, 92.47%, respectively, but the variation of the average temperature in June and August were relative small. Yield and plant height greatly with c. v. of 26.24, 23.41 %, respectively, 1, 000 grain weights show more or less c.v. of 3.83% and length capsule setting show still less variation. Correlation coefficients between maximun temperature in period of cultivation(from June to September) and yield are positively significant at the level of 5.1 %, respectively. Correlation coefficients amount the plant height, length capsule setting, number of capsules per plant, weight of 1, 000 grains and seed yield were positively significant at the level of 1 %, respectively. Simple linear regression equations by the least square method are estimated for number of capsules per plant(Y$_1$) and the maximun temperature in August(X) as $Y_1$=10.1255+0.1725X, and for yield(Y$_2$) and the maximun temperature in August(X) as $Y_2$=21.6151 + 1.3724X.

• Journal of Plant Biotechnology
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• v.45 no.4
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• pp.347-356
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• 2018

Chionanthus retusus is a small deciduous tree that is widely used in landscaping due to its beautiful white spring flowers and ornamental value. Conventional propagation through seeds requires one to two years of breaking dormancy. The objective of this study was to determine the conditions of in vitro germination in C. retusus. In vitro embryo culture was carried out to investigate the effects of six factors: basal media (McCown Woody Plant Medium (WPM) and Murashige and Skoog (MS)); plant growth regulators (different combinations and concentrations of naphthaleneacetic acid (NAA), 6-Benzylaminopurine (BA), and gibberellic acid ($GA_3$)); embryo age (collected weekly beginning 36 days after fruit setting); low temperature pretreatment (storing $4^{\circ}C$ for 1, 2, 3, and 4 weeks); coconut additives (100, 200, and $300ml{\cdot}L^{-1}$); and genotype (grouping plants depending on their flowering nature). The basal medium used in this study was WPM with $2mg{\cdot}L^{-1-1}\;GA_3$, $20g{\cdot}L^{-1}$ sucrose, and $6g{\cdot}L^{-1}$ Agar. WPM medium mixed with $GA_3$, resulted in higher germination rate as compared to when using a combination of auxin and cytokinin. $GA_3$ at $2mg{\cdot}L^{-1}$ was the most effective of all combinations and concentrations of PGRs. WPM medium with $2mg{\cdot}L^{-1}GA_3$ resulted in better and faster germination (75.93%). Embryos collected at 57 days after fruit setting had the highest percent of germinated seeds (87.04%) while low-temperature pretreatment of fruits at $4^{\circ}C$ for two weeks produced the highest germination (95.37%). These results of this study could be an open ground for development of an efficient protocol for commercial production of the ornamental tree.

• Journal of Forest and Environmental Science
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• v.34 no.6
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• pp.435-450
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• 2018

Phenological events of four Rhododendron tree species (viz. R. arboreum, R. arboreum ssp. delavayi var. delavayi, R. barbatum and R. kesangiae) was monitored in temperate mixed broad-leaved forests of Arunachal Pradesh, India. Phenological events like flower bud formation, flowering, fruit setting, fruit maturing, seed dispersal, leaf bud formation, leaf flushing, and leaf shedding were recorded. Indices i.e., phenophase sequence index (PSI), active phenophasic period of the species (APS) and index of reproductive/vegetative activity (RVA) were also calculated. Present study revealed that bark consistency, growth form and leaf pattern of the studied species have showed variations among the species. Rhododendron species exhibited the phenological events overlapping with other phenophases. The peak flower bud formation was observed during the winter; R. arboreum ssp. delavayi var. delavayi start flowering from December, while the flowering in rest three species exhibited during February to April. Fruit setting occurred during summer to autumn while fruit maturation revealed peak during November. Leaf bud formation illustrated two peaks in April and May, leaf flushing exhibited peak in June, while leaf shedding peaked during October to November. Active phenophasic period of the species were found 12 months, which revealed that species engage in various phenophase activities throughout the year. Phenophase sequence index ranged between 0.8 to 0.9 (PSI ${\geq}0.6$), signifies that species have a sequential arrangement of phenophases. Index of reproductive/vegetative activity of the species exemplified >1, indicate that the reproductive phenophases were dominance over vegetative phenophases. The study have provided substantial insight on the life cycle events of Rhododendron species and ecological approaches for further scientific study with recent climate change and effective management and conservation.

• Korean journal of applied entomology
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• v.18 no.2 s.39
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• pp.101-106
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• 1979

Present studies were carried out to get a basic information for biological control of soybean rod borer, Grapholitha glycinivorella Matsumura, causing main injury in soybean cultivation in Korea. 1474 native strains were cultivated in field to evaluate the pod borer damage. Pubescence density and color, maturity group, seed coat color, aphid and general leaf damage and seed damage by pod borer were investigated, and determined among their relationships. As another basic study for ecological control of insect, 6 leading varieties were planted on different planting date with 3 levels of plant spacing, on which pod borer damage and some related agronomic characters were studied. The results obtained one summarized as follows: Average injury of soybean pod borer was $5.2\%$ ranging $0-38\%$ in 1474 strains planted on 20 May. Non-significant correlations were found between pod borer damage and pubescence density and color, while pod borer damage closely related with maturity groupand aphid damage at $5\%$ level ofttests. Most severe damage was found in green seed coast color and maturity group V. Late and sparse plantings tend to have more damages to the pod borer than those of early and dense plantings. Pod setting date and period of pod maturing seemed related with pod borer damage. Bongeui and Chungbuk-baik cultivars were resistance to soybean pod borer, while Clark and Kumkang-daerip were susceptible in field tests.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.32 no.4
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• pp.392-402
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• 1987

To know the effect of presowing seed soaking with some growth substances (kinetin, IAA, ethrel and salicylic acid) on vegetative growth and yield contributing parameters in soybean [Glycine max (L.) Merrill] the investigation was undertaken. The salient features from the study are;-All the treatments showed the enhancement effect on vegetative growth, viz. seediling emergence, germination percentage, plant height, number of leaves and branches per plant as compared with control, whereas salicylic acid delayed the seedling emergence process and lowered the germination percentage.-Nodule initiation, number of nodules and nodule weight were hastened and increased respectively under all the treatments whereas IAA showed an opposite effect on all the parameters at the early stages of nodule development.-Kinetin, IAA and ethrel showed the significant enhancement effect on the levels of biochemical parameters throughout the time of seed development whereas salicylic acid and water showed the tendency similar to that of control.-Yield and its components, viz. number of flowers, pods and seeds per plant were significant increased under all the treatments but they didn't show any significant enhancement effect on number of seeds per pod and pod setting rate. One hundred seed weight was lower under all the treatments, indicating the dilution effect resulting from incapability of increased number and size of source to provide the increased size of sink with assimilates.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.3
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• pp.495-508
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• 1994

A backcalculation procedure to determine the layer moduli of flexible pavement structure is developed using matrix solution technique. Forward calculation computer program adopted in this backcalculation procedure is SINELA which is one of layered elastic computer programs. Data base system is used as a tool for setting initial seed moduli and depth to virtual bedrock in backcalculation procedure. The validity and applicability of the proposed backcalculation procedure are verified through various numerical model tests. From the results of comparison analysis with FPEDD1, it is found that the proposed procedure gives more efficient and accurate results.

• Korean Journal of Agricultural Science
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• v.44 no.2
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• pp.188-195
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• 2017

Biotech crops can only be commercialized after they receive safety approvals, which require thorough risk assessments of their release to the environment. Environmental release experiments are indispensable for environmental risk assessments, and each country has been preparing its own regulations for the safety management of experiments on the environmental release of biotech crops in confined fields. In this study, we compared and analyzed the safety management regulations of the environmental release of biotech crops in Korea, USA, Japan, European Union, and China. Each country had safety management regulations for the environmental release of biotech crops, and these regulations were generally not much different from the Korean regulations. However, there was a difference amongst the USA, Japan, and China in regulations for isolation distances to prevent gene diffusion through pollen-flow during environmental release experiments of biotech crops. In order to establish the isolation distance regulation suitable for the Korean environment, relevant data were collected and presented. For setting the isolation distance for environment release of biotech crops, it is suggested to refer to the isolation distance information provided in the Guidance of Seed Management in Korea. The results of this study are expected to help establish the safety management of biotech crops in Korea.

• Research in Plant Disease
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• v.24 no.2
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• pp.99-112
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• 2018

Certain agrochemicals may be tuned for increased effectiveness when downsized to nanoparticles (NPs), where one dimension is less than 100 nm. The NPs may function as fertilizers, pesticides and products to improve plant health through seed priming, growth promotion, and induction of systemic tolerance to stress. Formulations will allow targeted applications with timed release, reducing waste and pollution when compared to treatments with bulk-size products. The NPs may be a single component, such as nano-ZnO as a fertilizer, or be composites of compatible materials, for example where N, P, and K plus micronutrients are available. The active materials could be loaded into porous carriers or tethered to base nanostructures. Coatings could include such natural products alginate, chitosan, zein, or silica. Certain NPs are taken up and transported in the plant's phloem and xylem so systemic effects are feasible. Timed and targeted release of the active product could be achieved in response to changes in pH or availability of ligands within the plant or the rhizosphere. Global research has revealed the many potentials offered by NP formulations to aid sustainability in agriculture. Current work will provide information needed by regulatory agencies to assess their safety in the agricultural setting.