• Korean Journal of Breeding Science
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• v.51 no.4
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• pp.504-514
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• 2019

'Yechan' is a high grain quality mid-late maturing rice cultivar with lodging tolerance and multiple disease resistance. It was a derived from a cross between 'Hopum' and 'Iksan537' (cultivar name 'Haepum'). 'Hopum' is a high grain quality mid-late maturing rice cultivar with strong lodging tolerance and 'Haepum' is a high grain quality medium maturing rice cultivar with multiple disease resistance. To shorten the breeding period, another culture method was applied to the F₁ plants. 'Yechan' was selected through the pedigree method, yield trials, and local adaptability tests, with a high selection pressure for grain quality, lodging, and disease resistance. The heading date of 'Yechan' was August 14, one day later than that of 'Nampyeong'. 'Yechan' is a cultivar tolerant to lodging and it has short culms. It has multiple disease resistance against rice blast, rice stripe virus, and bacterial blight, including the K3a race, the most virulent race in Korea. The yield of 'Yechan' was similar to that of 'Nampyeong'. 'Yechan' showed excellent grain appearance, superior taste when cooked, and enhanced milling performance; thus, we concluded that it could contribute to the improvement of Korean japonica rice cultivar quality. 'Yechan', a high grain quality mid-late maturing rice cultivar with lodging tolerance and multiple disease resistance, would be suitable for cultivation in the southern plain area in Korea and has been utilized in the breeding programs aimed at enhancing the grain quality and stability for the cultivation of Korean japonica rice (Registration No. 7647).

• Journal of Practical Agriculture & Fisheries Research
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• v.21 no.1
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• pp.29-40
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• 2019

In Korea kiwifruit growing area is limited to southern coastal region and Jeju island, partly due to the lack of information on their cold hardiness in winter. This study was carried out to investigate cold hardiness of Korean kiwifruit cultivars in a period of dormancy for using it as preliminary data to expand the cultivation area of kiwifruit in Korea. A total of five kiwifruit cultivars in two species and hybrid, Actinidia deliciosa ('Hayward' and 'Garmrok'), A. chinensis ('Goldone') and A. arguta hybrid ('Bangwoori' and 'Skinny Green') were subjected to five freezing treatments of -12℃, -15℃, -18℃, -21℃ and -24℃. Cell membrane damage in all cultivars initiated in -18℃/32h and cell membrane stability was lost in -24℃ in most cultivars, except for 'Skinny Green'. Cold hardiness was estimated by 50% lethal temperature (LT₅₀) which was determined by triphenyl tetrazolium chloride (TTC) reduction. In branches, LT₅₀ was -15℃ in 'Hayward' and 'Garmrok', -18℃ in 'Bangwoori' and -21℃ in 'Goldone.' The LT₅₀ of buds on 'Hayward' and 'Garmrok' was 56 and 42 hours in -15℃ and 4 and 11 hours in -18℃, respectively; however, LT₅₀ of buds on 'Goldone' was 51 hours in -18℃ and that on 'Bangwoori' was 3 hours in -24℃. Cold hardiness results imply that it may be difficult for cultivars in A. deliciosa such as 'Hayward' and 'Garmrok' to be grown in the north of southern coastal region in Korea; however, it can be possible for several cultivars in A. chinensis and A. arguta hybrid to be grown in the northern part of Korean kiwifruit belt if cold tolerance in the thaw is confirmed.

• Journal of Practical Agriculture & Fisheries Research
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• v.20 no.1
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• pp.35-47
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• 2018

A edible mushroom, Clitocybe maxima (Lentinus giganteusis) commercially cultivated in China and Taiwan. However, the researches of cultivation and cultural characteristics were not reported in Korea. In this study, we conducted on cultural characteristics and artificial cultivation of C. maxima. Six isolates were collected from China(3 isolates, commercial strain), Taiwan(1 isolate, commercial strain) and Korea(2 isolates, wild type). C. maxima and L. giganteus collected in China and Taiwan, respectively, are the same in China and are estimated to be of the same species as cultured characteristics. The mycelial growth of the collected strains was not significantly different in agar medium but it showed the best growth in YPMG in liquid culture. Optimum temperature for mycelial growth and induction of fruit body were 25℃ and 30℃, respectively. In order to artificial cultivation of C. maxima, cultural characteristics and artificial cultivation were carried out using agricultural by-products and forestry by-products materials. Mycelial growth was suitable in rice straw, cottonwood sawdust, corncob and rice seed medium, and it was selected as a cultivation medium. The suitable medium for artificial cultivation of C. maxima was selected to mixed medium 2(compounding ratio(v/v): 55% of hardwood sawdust, 5% of cottonseed pellets, 10% of cottonseed, 15% of beet pulp, 15% of swollen rice husks). It took about 30 days to be able to harvest, it was faster than oyster mushrooms. The cultivation period was about 30days. A isolate, CMA-002 was not initiation to fruit body primordiuma on the used cultivation substrate. Other 5 isolates were initiate and development to fruit body on the substrate used in this study. The strain CMA-003 was initiated to be fruiting body by 8~10 days after induction of fruiting body in all of the substrates. Isolate CMA-003 was generate to a bundle fruit body. Other isolates, however, were form fruit body individually. The CMA-003 strain was likely highly recommendable strains for farming. The optimum conditions for the induction and growth of C. maxima fruit body were 25~30℃, 8 hr illumination per day with white fluorescent lamp, 90~95% relative humidity, and 1,500 ppm of CO₂ concentration in a cultivation room.

• Journal of Practical Agriculture & Fisheries Research
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• v.18 no.1
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• pp.79-91
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• 2016

Quality factors which characterize 11 kinds of farm-manufactured apple Jangachi and commercial Jangachi, have been studied in order to provide a guideline to improve the quality and marketing strategy of farm-manufactured pickled apples. Moisture content ranged from 74% to 84% and 81% to 91% in Doenjang Jangachi and vinegar Jangachi, respectively; 38% to 64% in Kochujang Jangachi; 57% to 64% in radish Kochujang Jangachi. Moisture content was 89% in Doenjang Jangachi. Even though moisture content of apple Kochujang Jangachi indicated 48% which is lower than that of radish Jangachi, it was higher than that of a persimmon pickled in Kochujang (38%) and that of Japanese apricot Jangachi (49%). pH and titratable acidity, two indicators used to determine the appropriate ripening period of Jangachi, were pH 3.4~5.6, 0.03~0.14%, respectively. The pH ranged from 5.2 to 5.6 in radish Jangachi; 3.4 to 4.1 in Cucumber Jangachi. pH of persimmon Jangachi, Japanese apricot Jangachi and apple Jangachi showed 4.1, 3.5 and 4.1, respectively. Compared with the pH of traditional Jangachi (3.03~5.36), pH of all of the above Jangachi fall into an appropriate range. The brix of apple Jangachi (30%) was 12% to 18% higher than that of Kochujang radish Jangachi, but it was relatively lower than that of persimmon Jangachi (39%) and that of Japanese apricot Jangachi (49%). Salinity of Jangachi varied depending on which marinating material was used. Salinity in the descending order according to each marinating material demonstrated Kanjang (6% to 13%), Doenjang (7%), Kochujang (3% to 4%). Salinity of apple Jangachi was 3.28% which was relatively lower than that of commercial Jangachi which used either Kanjang or Doenjang as its marinating material. Chromaticity test shows that the brightness value of apple Jangachi (54.70) was similar to that of cucumber Jangachi (50.86, 56.02); the redness value and yellowness of apple Jangachi (16.21 and 26.78) were higher than the redness value (7.27 to 11.23) and the yellowness value (10.62 to 14.69) of radish Kochujang Jangachi. Sensory Characteristics value of apple Jangachi, along with radish and cucumber Jangachi in its color, odor and taste (7.00, 7.50, 7.00, respectively) placed high on the list implying higher preference. However, overall preference value of apple Jangachi was 6.83 which was lower than that of Japanese apricot Jangachi or that of radish Jangachi. The result can be explained by the tendency of people preferring crispy Jangachi and points out that the texture of apple Jangachi needs to be improved to gain popularity. Furthermore, for increased sales of apple Jangachi as a niche product, more rigorous market testing is required.

• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.3
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• pp.282-288
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• 2023

In this study, we analyzed the amount of roadside fine dust generated from newly constructed specially modified asphalt pavement and general asphalt pavement from existing roads. We collected the 1,000 g (100 g/day) of dust samples from the roadside of the express bus terminal and commercial facility area in Chungcheongnam-do's C site at three-day intervals during the summer of 2022 and 2023. The collected samples were separated from fine dust according to size in the 75-150 ㎛ range and, were separated only from Tire and Road Wear Particles through density separation. No.1-3 are general asphalt pavement section as an existing road. Fine dust and Tire and Road Wear Particles in No.1-3 were 24.27 g, 24.36 g, 0.53 g, and 0.53 g, respectively, and the quantitative results for 2022 and 2023 were similar. On the other hand, No.4-6 are newly constructed specially modified asphalt pavement section. Fine dust decreased by 14.8 % and tire and road wear particles decreased by 29.6 % in 2023 compared to 2022 in No.4-6. In addition, according to the results of thermogravimetric analysis, Tire and road wear particles in No.1-3 are tire and road components at 30 % and 70 %, respectively. And Tire and road wear particles in No.4-6 are tire and road components at 35 % and 65 % in 2023, respectively. From these results, it was confirmed that the newly constructed specially modified asphalt pavement can be effective in reducing roadside fine dust and Tire and Road Wear Particles. However, there may be some shortcomings in conclusive research results due to limited space and sample collection period. In the future, we plan to conduct various case studies.

• Journal of Wetlands Research
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• v.25 no.4
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• pp.306-314
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• 2023

Stream sediments are an important component of water quality management because they are receptors of various pollutants such as heavy metals and organic matters emitted from upland sources and can be secondary pollution sources, adversely affecting water environment. To effectively manage the stream sediments, identification of primary sources of sediment contamination and source-associated control strategies will be required. We evaluated the performance of machine learning models in identifying primary sources of sediment contamination based on the physico-chemical properties of stream sediments. A total of 356 stream sediment data sets of 18 quality parameters including 10 heavy metal species(Cd, Cu, Pb, Ni, As, Zn, Cr, Hg, Li, and Al), 3 soil parameters(clay, silt, and sand fractions), and 5 water quality parameters(water content, loss on ignition, total organic carbon, total nitrogen, and total phosphorous) were collected near abandoned metal mines and industrial complexes across the four major river basins in Korea. Two machine learning algorithms, linear discriminant analysis (LDA) and support vector machine (SVM) classifiers were used to classify the sediments into four cases of different combinations of the sampling period and locations (i.e., mine in dry season, mine in wet season, industrial complex in dry season, and　industrial complex in wet season). Both models showed good performance in the classification, with SVM outperformed LDA; the accuracy values of LDA and SVM were 79.5% and 88.1%, respectively. An SVM ensemble model was used for multi-label classification of the multiple contamination sources inlcuding landuses in the upland areas within 1 km radius from the sampling sites. The results showed that the multi-label classifier was comparable performance with sinlgle-label SVM in classifying mines and industrial complexes, but was less accurate in classifying dominant land uses (50~60%). The poor performance of the multi-label SVM is likely due to the overfitting caused by small data sets compared to the complexity of the model. A larger data set might increase the performance of the machine learning models in identifying contamination sources.

• Journal of The Korean Society of Grassland and Forage Science
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• v.43 no.4
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• pp.216-224
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• 2023

Since maize (Zea mays L.) originated in central and south America, it requires warm climate conditions throughout its growing season. Growth halts when night-time temperatures drop below 10℃, and the plant may die if temperature reach -1.7℃. Thus, temperature should be maintained between 10 and 30℃ from seeding to maturity. The germination temperature for maize should be at least 8-11℃, whit an optimal range 32-34℃. Since temperature significantly affects the germination rate and period, it plays a crucial role in maize growth. In this study, we evaluated the quantity and feed value of 11 major varieties to determine those best suited for maize cultivation as feed in higher latitude, specifically in Democratic People's of Republic of Korea, below 38 degrees north. A cultivation test was also conducted in Suwon in Republic of Korea, to assess adaptability in areas south of Mt. Suyang. Among the varieties tested, Shinhwangok2 reached silking the fastest, in 65 days, while Gwangpyeongok took the longest at 75 days. The stem length of all varieties exceeded 230 cm. Gwangpyeongok had the tallest stems, while Daanok and Shinhwangok2ho displayed the highest ear ratios. Dacheongok presented the highest values in both dry matter and TDN quantity, with 31,420 kg/ha and 21,66 kg/ha respectively. Pyeonggangok had the highest crude protein content at 8.0%. TDN (%) ranged from 57-68%, with Hwangdaok reaching up to 68%. Based on these findings, Dacheongok and Pyeonggangok appear to be the most suitable varieties for cultivation in terms of both quantity and feed value.

• Journal of the Korean Society of Earth Science Education
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• v.16 no.3
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• pp.319-327
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• 2023

This study involved 22 students in one class of 4th year science intensive course at B College of Education. We investigated the changes in the acquisition of knowledge in the field of geology and the perception of geological exploration among pre-service teachers. For this study, a period of four weeks was designated for a semester to a geological field trip. For the geological exploration, the Geoparks of City B (Geumjeongsan Mountain, Amnam Park, Igidae, Dusong Peninsula, Jangsan, Taejongdae, and Hwangnyeongsan Mountain) were designated. The concept of geology and rocks has been extracted from the concepts that can be found in the Geopark. The composition of the group was composed of one group of four members autonomously. The other two of the pre-service teachers joined a group of friends with whom they had an affinity. After the geological field trip, the materials were organized by group and PPT presentations were made during the lecture time where all the members could listen. The extent to which the pre-service teachers acquired the concepts of geology and rocks after conducting the geological field trip was interpreted as the result of pre- and post-statistical processing. In addition, we interpreted what kind of perception the pre-service teachers had after the geological field trip as a result of the statistical processing before and after. Based on the results of the study, the following conclusions were drawn: First, it was effective for the pre-service teachers to acquire the concepts of strata and rocks after the geological field trip. The reason for this is that the experience of the pre-service teachers in conducting geological field trips has changed their perception of geological field trips. In addition, it is interpreted that these results were obtained because the pre-service teachers had a high level of interest in geology and rocks. Second, the pre-service teachers were able to gain confidence after the geological field trip. This reason is interpreted as the fact that they were able to gain confidence in geological exploration by exploring and experiencing the sites of the Geopark for each group.

• Korean Journal of Agricultural and Forest Meteorology
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• v.25 no.4
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• pp.359-367
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• 2023

Grapes are one of the most important fruit trees both domestically and globally. Recently, changes in plant phenology and frequent low temperatures due to climate change are increasing the possibility of damage to grape shoots in spring, which is a serious threat to grape production. This study was conducted to investigated the severity of shoots damage and the change of free sugar content in the plant organs by phenological stage, especially, from germination to leafing period. Furthermore, in order to compare the cold hardiness among grape varieties including 'Campbell Early', 'Kyoho' and 'Shine Muscat' widely grown in Korea, lethal temperature (LT₅₀) and free sugar content by grape variety were analyzed. Shoot damage by low temperatures continued to increase as the phenological stage progressed gradually, from the bud burst to the fourth leafing stage. On the other hand, the free sugar content of each organ except leaves continued to decrease, showing pattern to similar to cold hardiness. This indicates a close relationship between free sugar content and cold hardiness. In terms of cold hardiness comparison among grape varieties, 'Shine Muscat' showed the highest cold resistance in the leafing stage with the lowest LT₅₀ and the highest total free sugar content. Next was 'Kyoho' and 'Campbell Early'. There are clear differences in cold hardiness depending on the variety. However, it is not the same at all growth stage. It may change according to phenological stage and influenced by free sugar content at that time.

• Journal of The Korean Association For Science Education
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• v.43 no.6
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• pp.549-562
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• 2023

The current society is in the VUCA era, where various risks produced by humans are spread along with the development of science and technology. There is a need to increase the level of risk literacy of citizens to strengthen their daily preparedness to respond to these risks. For this on, it is necessary to reconsider the role of science education so that risks can be perceived and responded to scientifically and objectively. Accordingly, in order to investigate the role of science education in a risk society, this study reviewed the history of risk perception and response related to science and analyzed its characteristics. In this process, perception and response to risks arising from blood pressure were analyzed in three contexts (historical context, curriculum context, textbook context). For historical context, journals registered in SCIE were selected as research subjects among journals where research related to the history of knowledge of the heart and cardiovascular system was conducted. Papers with the keywords 'hypertension' and 'history' were selected from the journals, and changes in perception and responses related to blood pressure were compared and analyzed by period. The curriculum context is analyzed from the 1st national curriculum to the 2022 revised curriculum, and content elements and achievement standard related to blood pressure were compared and analyzed. It was confirmed that risks arising from blood pressure were not included from the 1st to the 6th national curriculum, and that risks arising from blood pressure were included from the 7th national curriculum (excluding the 2009 revised curriculum). For the textbook context, the 7th national curriculum BiologyⅠ, the 2015 revised curriculum Life ScienceⅠ, and Health were selected, and through text mining, keywords that representing curriculums and textbooks were selected, and the presentation of risk perception and response was analyzed based on the keywords. And by analyzing the figures and tables presented in the textbook, the characteristics of risk perception and risk response were derived. This study is meaningful in that it was able to confirm the role of risk perception and response in science education.