• Korean Journal of Agricultural and Forest Meteorology
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• v.17 no.2
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• pp.156-164
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• 2015

High temperature stress would affect rice production in the future as heat wave is expected to occur frequently under climate change conditions. The objective of this study was to obtain rudimentary information to assess the impact of heat stress on rice yield and its yield component in Korea. Two rice cultivars "Hwaseongbyeo" (Japonica) and "Dasanbyeo" (Tongil-type) were grown at different nitrogen fertilization levels in two seasons. These cultivars were grown in 1/5000a Wagner pot placed within four plastic houses where temperature was controlled at ambient, ambient$+1.5^{\circ}C$, ambient$+3^{\circ}C$ and ambient$+5^{\circ}C$ throughout the rice growing season in Suwon ($37^{\circ}16^{\prime}N$, $128^{\circ}59^{\prime}E$), Korea. The degree of temperature change affected grain yield whereas the level of nitrogen had little impact on grain yield. The number of panicle per pot and spikelet per panicle were not significantly different among temperature treatments in both cultivars tested. In contrast, 1000-grain weight and ripened grain ratio were decreased significantly under the treatments raising the air temperature to the level of $5.0^{\circ}C$ and $1.5^{\circ}C$ above the ambient air temperature in Dasanbyeo and Hwaseongbyeo, respectively. Reduction of 1000-grain weight and ripened grain ratio under the temperature treatments of $3.0^{\circ}C$ and $5.0^{\circ}C$ above the ambient air temperature resulted in significantly less grain yield for Dasanbyeo and Hwaseongbyeo, respectively. The greater sensitivity of grain yield to temperature increase in Dasanbyeo was attributable to the sharp decrease of 1000-grain weight and ripened grain ratio with the temperature rise above $23^{\circ}C$ during ripening period. On the other hand, Hwaseongbyeo had little variation of them in the temperature range of $23-27^{\circ}C$. These results suggested that grain yield would decrease under future climate conditions due to grain weight decreased by shorter grain filling period as well as the ripened grain ratio reduced by spikelet sterility and early abortion of rice kernel development. Thus, it would be essential to use cultivars tolerant to heat stress for climate change adaptation, which merits further studies for developing varieties that have traits to avoid spikelet sterility and early abortion of rice kernel, e.g., early morning flowering, under heat wave.

• Korean Journal of Plant Resources
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• v.31 no.5
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• pp.489-497
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• 2018

In Korea, common and Tartary buckwheat are cultivated mainly in spring and fall, however the available buckwheat varieties are still very limited. In this study, we have evaluated buckwheat germplasm for agronomic traits and compared flavonoids contents in different cultivation period and collection area. In common buckwheat, the number of days from sowing to flowering was 40 and 31 days and from sowing to maturity took 90 and 69 days in spring and fall cultivation, respectively. The number of nodes and branches were higher in spring cultivation while the hundred seed weight was higher in fall cultivation. The average flavonoids contents in common buckwheat were 0.20 mg/g dry weight (DW) and 0.40 mg/g DW in spring and fall cultivation, respectively. The highest flavonoids content was detected in Jeonnam accessions with 0.29 mg/g DW and 0.43 mg/g DW during spring and fall cultivation, respectively. The flavonoids contents were varied from 1.5 to 2.5 times according to the collection area. These results suggest that the agronomic traits and flavonoids contents were vary depending on the cultivation environment and germplasm collection area. Therefore, it is necessary to select the material by considering the characteristics of the germplasm for breeding of new varieties.

• Horticultural Science & Technology
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• v.32 no.4
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• pp.517-524
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• 2014

As an assessment of substantial equivalence and environmental risks of branchless chrysanthemum GM lines (LeLS69, LeLS76, LeLS80) developed in Korea, we investigated their degree of branchlessness and developmental characteristics including growth and flowering, as well as the stability of populations of insect pests and soil microbes. The GM lines were compared with a control variety, 'Jinba'. LeLS80 showed the highest level of branchlessness among the three GM lines, whereas abnormal axillary buds developed in lines LeLS76 and LeLS69. There were no significant differences between the growth characteristics of 'Jinba' and the GM lines. The branchlessness LeLS80 was increased during the summer season, suggesting that it is a useful germplasm for developing elite branchless cultivars. These GM lines showed no significant differences in the occurrence of five insect pests including aphids, mites, leaf miners, thrips, and whiteflies. Similarly, for soil microbes including bacteria and actinomycetes, there were no significant differences between 'Jinba' and the GM lines. However, there was a higher occurrence of fungi in the GM lines compared to 'Jinba'. Our findings suggest that 'Jinba' and the GM lines are substantially equivalent, although further monitoring studies are needed to confirm this.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.66 no.2
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• pp.120-129
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• 2021

Securing a range of wheat resources is of particular importance with respect to wheat breeding, as it provides a broad genetic foundation. Although wheat breeders have used different wheat germplasms as material resources in current breeding systems, the traits of most germplasms collected from foreign countries differ from the unique traits that have evolved in the Korean environment. In this study, conducted over a 2-year period (2018 and 2019), we therefore evaluated the agricultural traits 1,967 wheat germplasms collected not only in Korea but also worldwide. During the period from sowing to February, the average temperature in 2019 was greater than 1℃, whereas from March to June, the average temperature was approximately 0.9℃ higher in 2018. Compared with the growth recorded in 2018, the stem length in 2019 increased by approximately 20 cm in 2019, and there were notable differences heading date and maturation between 2018 and 2019. In 2019, the heading dates of 973 and 713 wheat resources were earlier and later than those in 2018, respectively. Moreover, stem length was found to be highly correlated with the heading date and maturation. In Korea, where the rainy season and tine of rice transplantation overlap with the time of wheat harvest, early flowering time with high grain yield has been the most important selection target with respect to wheat breeding. We anticipate that the findings of this study will provide would use a foundation for the selection of elite materials and the development of resource core-sets for Korean wheat breeding programs.

• Journal of the Korean Institute of Landscape Architecture
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• v.49 no.1
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• pp.70-82
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• 2021

The purpose of this study is to reveal the tendency of planting design through the analysis of the planting of designer's gardens in the Suncheon Bay National Garden and to derive implications for future garden planting designs. The results of the study are as follows: First, the results of the study show that the practice of tree-based planting is still valid. Large growing trees such as 'Pinus densiflrora', 'Celtis sinensis', 'Zelkova serrata', 'Machilus thunbergii', 'Pinus strobus' overwhelmed the size of the designer's garden(150 to 390㎡). Second, the selection of trees tended to be made considering the designer's intention and the decorative effects rather than by considering the physiological and ecological conditions of the site. Third, among the herbaceous, the rate of the planting of perennials was high. Fourth, the flowering period of planted herbaceous was the most common in summer, followed by spring, fall, and winter. Fifth, the frequency color of the planted herbaceous was the most common in summer, followed by spring, fall, and winter. Fifth, in terms of flower color frequency, the most common was the yellow-series, followed by red-series, blue-series Sixth, average height herbaceous plants(20~60cm) were planted the most(47.4%). Seventh, structural plants that determined the garden's framework depended on trees, and the focal plants mainly utilized were evergreen trees, and the midrange plants were the planted herbaceous plants. The implications derived from the above findings are as follows: First, to ensure the garden's quality and sustainability, the selection of trees should be carefully considered, not considering only the artist's intention but also taking into account the physical and ecological conditions. Second, herbaceous plants can be used in various ways― the garden's focal plants, midrange plants, and ground covers, so more active herbaceous planting needs to be considered. Third, in consideration of the winter landscape, herbaceous planting using characteristics, such as fruits and stems, as well as flower colors should be considered. Fourth, blue and black color herbaceous plants have a noticeable effect even in a small amount, so it is necessary to plant them actively. Fifth, for the design of herbaceous planting, where the individual property of plants can be expressed, the design method should be considered.

• Journal of Bio-Environment Control
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• v.33 no.2
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• pp.88-98
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• 2024

This study provides basic data on the growth and production of seedlings produced in plant factories with artificial lighting by comparing seedling quality, growth and fruit characteristics, and production after transplanting cucumber seedlings according to environmental differences between plant factories with artificial lighting and conventional nurseries in greenhouse. The control group consisted of greenhouse seedlings (GH) grown in the conventional nursery before transplanting. Plant factory to greenhouse seedlings (PG) were grown for 9 days in a plant factory with artificial lighting and for 13 days in an conventional nursery. Plant factory seedlings (PF) were grown in a plant factory with artificial lighting for 22 days until planting. In terms of seedling quality, PFs had the highest relative growth rate and compactness and the best root zone development. After transplanting PFs tended to grow faster, the first harvest date was 2 days earlier than that of GHs, and the growing season ended 1 day earlier. The female flower flowering rate of the PFs was high, and the fruit set rate was of PF the lowest. The production per unit area was highest for PFs at 10.23kg Performance index on the absorption basis, the most sensitive chlorophyll fluorescence parameter, was highest at 4.14 for PFs at 4 weeks after transplantation. By comparing the maximum quantum yield of primary PS II photochemistry and dissipated energy flux per PS II reaction center electron at 4 weeks after transplantation, PFs tended to be the least stressed. PFs had the best seedling quality, growth, and production after planting, and fruit quality was consistent with that of greenhouse seedlings. Therefore, plant factory seedlings can be used in the field.

• Magazine of the Korean Society of Agricultural Engineers
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• v.11 no.4
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• pp.1775-1782
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• 1969

The results of the study on the consumptine use of irrigated water in paddy fields during the growing season of rice plants are summarized as follows. 1. Transpiration and evaporation from water surface. 1) Amount of transpiration of rice plant increases gradually after transplantation and suddenly increases in the head swelling period and reaches the peak between the end of the head swelling poriod and early period of heading and flowering. (the sixth period for early maturing variety, the seventh period for medium or late maturing varieties), then it decreases gradually after that, for early, medium and late maturing varieties. 2) In the transpiration of rice plants there is hardly any difference among varieties up to the fifth period, but the early maturing variety is the most vigorous in the sixth period, and the late maturing variety is more vigorous than others continuously after the seventh period. 3) The amount of transpiration of the sixth period for early maturing variety of the seventh period for medium and late maturing variety in which transpiration is the most vigorous, is 15% or 16% of the total amount of transpiration through all periods. 4) Transpiration of rice plants must be determined by using transpiration intensity as the standard coefficient of computation of amount of transpiration, because it originates in the physiological action.(Table 7) 5) Transpiration ratio of rice plants is approximately 450 to 480 6) Equations which are able to compute amount of transpiration of each variety up th the heading-flowering peried, in which the amount of transpiration of rice plants is the maximum in this study are as follows: Early maturing variety ; Y=0.658+1.088X Medium maturing variety ; Y=0.780+1.050X Late maturing variety ; Y=0.646+1.091X Y=amount of transpiration ; X=number of period. 7) As we know from figure 1 and 2, correlation between the amount evaporation from water surface in paddy fields and amount of transpiration shows high negative. 8) It is possible to calculate the amount of evaporation from the water surface in the paddy field for varieties used in this study on the base of ratio of it to amount of evaporation by atmometer(Table 11) and Table 10. Also the amount of evaporation from the water surface in the paddy field is to be computed by the following equations until the period in which it is the minimum quantity the sixth period for early maturing variety and the seventh period for medium or late maturing varieties. Early maturing variety ; Y=4.67-0.58X Medium maturing variety ; Y=4.70-0.59X Late maturing variety ; Y=4.71-0.59X Y=amount of evaporation from water surface in the paddy field X=number of period. 9) Changes in the amount of evapo-transpiration of each growing period have the same tendency as transpiration, and the maximum quantity of early maturing variety is in the sixth period and medium or late maturing varieties are in the seventh period. 10) The amount of evapo-transpiration can be calculated on the base of the evapo-transpiration intensity (Table 14) and Tablet 12, for varieties used in this study. Also, it is possible to compute it according to the following equations with in the period of maximum quantity. Early maturing variety ; Y=5.36+0.503X Medium maturing variety ; Y=5.41+0.456X Late maturing variety ; Y=5.80+0.494X Y=amount of evapo-transpiration. X=number of period. 11) Ratios of the total amount of evapo-transpiration to the total amount of evaporation by atmometer through all growing periods, are 1.23 for early maturing variety, 1.25 for medium maturing variety, 1.27 for late maturing variety, respectively. 12) Only air temperature shows high correlation in relation between amount of evapo-transpiration and climatic conditions from the viewpoint of Korean climatic conditions through all growing periods of rice plants. 2. Amount of percolation 1) The amount of percolation for computation of planning water requirment ought to depend on water holding dates. 3. Available rainfall 1) The available rainfall and its coefficient of each period during the growing season of paddy fields are shown in Table 8. 2) The ratio (available coefficient) of available rainfall to the amount of rainfall during the growing season of paddy fields seems to be from 65% to 75% as the standard in Korea. 3) Available rainfall during the growing season of paddy fields in the common year is estimated to be about 550 millimeters. 4. Effects to be influenced upon percolation by transpiration of rice plants. 1) The stronger absorbtive action is, the more the amount of percolation decreases, because absorbtive action of rice plant roots influence upon percolation(Table 21, Table 22) 2) In case of planting of rice plants, there are several entirely different changes in the amount of percolation in the forenoon, at night and in the afternoon during the growing season, that is, is the morning and at night, the amount of percolation increases gradually after transplantation to the peak in the end of July or the early part of August (wast or soil temperature is the highest), and it decreases gradually after that, neverthless, in the afternoon, it decreases gradually after transplantation to be at the minimum in the middle of August, and it increases gradually after that. 3) In spite of the increasing amount of transpiration, the amount of daytime percolation decreases gadually after transplantation and appears to suddenly decrease about head swelling dates or heading-flowering period, but it begins to increase suddenly at the end of August again. 4) Changs of amount of percolation during all growing periods show some variable phenomena, that is, amount of percolation decreases after the end of July, and it increases in end August again, also it decreases after that once more. This phenomena may be influenced complexly from water or soil temperature(night time and forenoon) as absorbtive action of rice plant roots. 5) Correlation between the amount of daytime percolation and the amount of transpiration shows high negative, amount of night percolation is influenced by water or soil temperature, but there is little no influence by transpiration. It is estimated that the amount of a daily percolation is more influenced by of other causes than transpiration. 6) Correlation between the amount of night percoe, lation and water or soil temp tureshows high positive, but there is not any correlation between the amount of forenoon percolation or afternoon percolation and water of soil temperature. 7) There is high positive correlation which is r=+0.8382 between the amount of daily percolation of planting pot of rice plant and amount and amount of daily percolation of non-planting pot. 8) The total amount of percolation through all growin. periods of rice plants may be influenced more from specific permeability of soil, water of soil temperature, and otheres than transpiration of rice plants.