• Current Research on Agriculture and Life Sciences
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• v.31 no.1
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• pp.61-64
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• 2013

This study identified the effect of night time temperatures on the flowering period of spray-chrysanthemum during the summer season in South Korea. According to the results for 2005, the temperature at night time sustained more than $25^{\circ}C$ for 23.6 days during the short day period and delayed the flowering period for 22 days. Similar observations were reported in 2006, as the night time temperature sustained more than $25^{\circ}C$ for 23.6 days during the short day period and delayed flowering period for 23 days. The results for 2007 year showed that night time temperature sustained more than $25^{\circ}C$ for 31.9 days during the same period and delayed flowering for 31 days. In conclusion, based on the results for 2005 to 2007, a specific correlation was found between high night time temperatures and a delayed flowering period for the 'Euro' spray-chrysanthemum.

• Molecules and Cells
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• v.38 no.1
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• pp.81-88
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• 2015

Flowering time (or heading date) is controlled by intrinsic genetic programs in response to environmental cues, such as photoperiod and temperature. Rice, a facultative short-day (SD) plant, flowers early in SD and late in long-day (LD) conditions. Casein kinases (CKs) generally act as positive regulators in many signaling pathways in plants. In rice, Heading date 6 (Hd6) and Hd16 encode $CK2{\alpha}$ and CKI, respectively, and mainly function to delay flowering time. Additionally, the major LD-dependent floral repressors Hd2/Oryza sativa Pseudo-Response Regulator 37 (OsPRR37;hereafter PRR37) and Ghd7 also confer strong photoperiod sensitivity. In floral induction, Hd16 acts upstream of Ghd7 and CKI interacts with and phosphorylates Ghd7. In addition, Hd6 and Hd16 also act upstream of Hd2. However, whether CKI and $CK2{\alpha}$ directly regulate the function of PRR37 remains unclear. Here, we use in vitro pull-down and in vivo bimolecular fluorescence complementation assays to show that CKI and $CK2{\alpha}$ interact with PRR37. We further use in vitro kinase assays to show that CKI and $CK2{\alpha}$ phosphorylate different regions of PRR37. Our results indicate that direct posttranslational modification of PRR37 mediates the genetic interactions between these two protein kinases and PRR37. The significance of CK-mediated phosphorylation for PRR37 and Ghd7 function is discussed.

• Korean Journal of Agricultural and Forest Meteorology
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• v.16 no.4
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• pp.396-402
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• 2014

The spring season in Korea features a dynamic landscape with a variety of flowers such as magnolias, azaleas, forsythias, cherry blossoms and royal azaleas flowering sequentially one after another. However, the narrowing of south-north differences in flowering dates and those among the flower species was observed in 2014, taking a toll on economic and shared communal values of seasonal landscape. This study was carried out to determine whether the 2014 incidence is an outlier or a mega trend in spring phenology. Data on flowering dates of forsythias and cherry blossoms, two typical spring flower species, as observed for the recent 60 years in 6 weather stations of Korea Meteorological Administration (KMA) indicate that the difference spanning the flowering date of forsythias, the flower blooming earlier in spring, and that of cherry blossoms that flower later than forsythias was 30 days at the longest and 14 days on an average in the climatological normal year for the period 1951-1980, comparing with the period 1981-2010 when the difference narrowed to 21 days at the longest and 11 days on an average. The year 2014 in particular saw the gap further narrowing down to 7 days, making it possible to see forsythias and cherry blossoms blooming at the same time in the same location. 'Cherry blossom front' took 20 days in traveling from Busan, the earliest flowering station, to Incheon, the latest flowering station, in the case of the 1951-1980 normal year, while 16 days for the 1981-2010 and 6 days for 2014 were observed. The delay in flowering date of forsythias for each time period was 20, 17, and 12 days, respectively. It is presumed that the recent climate change pattern in the Korean Peninsula as indicated by rapid temperature hikes in late spring contrastive to slow temperature rise in early spring immediately after dormancy release brought forward the flowering date of cherry blossoms which comes later than forsythias which flowers early in spring. Thermal time based heating requirements for flowering of 2 species were estimated by analyzing the 60 year data at the 6 locations and used to predict flowering date in 2014. The root mean square error for the prediction was within 2 days from the observed flowering dates in both species at all 6 locations, showing a feasibility of thermal time as a prognostic tool.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.68 no.4
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• pp.304-312
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• 2023

Plant breeding is a time-consuming process, mainly due to the limited annual generational advancement. A speed breeding system, using LED light sources, has been applied to accelerate generational progression in various crops. However, detailed protocols applicable to soybeans are still insufficient. In this study, we report the optimized protocols for a speed breeding system comprising 12 soybean varieties with various maturity ecotypes. We investigated the effects of two light qualities (RGB ratio), three levels of light intensity (PPFD), and two soil conditions on the flowering time and development of soybeans. Our results showed that an increase in the red wavelength of the light spectrum led to a delay in flowering time. Furthermore, as light intensity increased, flowering time, average internode length, and plant height decreased, while the number of nodes, branches, and pods increased. When compared to agronomic soil, horticultural soil resulted in an increase of more than 50% in the number of nodes, branches, and pods. Consequently, the optimal conditions were determined as follows: a 10-hour short-day photoperiod, an equal RGB ratio (1:1:1), light intensity exceeding 1,300 PPFD, and the use of horticultural soil. Under these conditions, the average flowering time was found to be 27.3±2.48 days, with an average seed yield of 7.9±2.67. Thus, the speed breeding systems reduced the flowering time by more than 40 days, compared to the average flowering time of Korean soybean resources (approximately 70 days). By using a controlled growth chamber that is unaffected by external environmental conditions, up to 6 generations can be achieved per year. The use of LED illumination and streamlined facilities further contributes to cost savings. This study highlights the substantial potential of integrating modern crop breeding techniques, such as digital breeding and genetic editing, with generational shortening systems to accelerate crop improvement.

• Korean Journal of Agricultural and Forest Meteorology
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• v.18 no.3
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• pp.162-169
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• 2016

The agrometeorological reference index means 'the agrometeorological damage possibility' or the possibility of the normal year climate condition to damage the crop cultivation in a certain region. It is a reference used to compare the cultivation risk of a crop by region. The global climate warming is expected to increase the winter temperature. At the same time, the frequency of extreme weather events will also increase. Therefore, people pay attention to the potential of low temperature-induced damages (e.g., frost damage and injury) to fruit trees under the future climate condition. However, simple damage projection based on climate conditions does not help the climate change adaptation in the practical aspect because the climate change affects the phenology of fruit trees as well. This study predicted the phenology of the pear, peach, and apple trees by using the climate change scenarios of major regions. Furthermore, low temperature induced agrometeorological reference indices were calculated based on the effects of temperature on each plant growth stage to predict the damage possibility. It was predicted that the breaking rest would delay more in the future while the bud-burst date and flowering date will be earlier. In Daegu, Jeonju, and Mokpo, the breaking rest delayed more as time passed. The bud-burst date and flowering date of Seoul and Incheon regions were later than other regions. Seoul and Incheon showed a similar pattern, while Daegu and Jeonju revealed a similar pattern. Busan and Mokpo also showed a similar pattern. All regions were safe from the frost damage during the dormancy period. However, plants were vulnerable to frost damage between the breaking rest and the bud-burst period. Regions showed different frost damage patterns between the bud-burst period and the flowering period. During the bud-burst and flowering period, the risk level decreased in general, although the risk of some areas tended to increase.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.3
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• pp.147-150
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• 2002

To investigate the effects of Harvesting time and additives on the quality of peanut silage, the silage was mixed in combination with peanut leaf and stem, rice and barley straw, inoculant etc. Harvesting time at peanut growth stage was the best at 90 days after flowering with 30 branches,81 g of 100-seed weight, and 77% of shelling rate with low diseases in leaf and stem. By delay of harvest, diseases and lodging were increased. The yield of forage was the highest at 90 days after flowering as 52 t/ha, and seed yield was at 110 days as 3.72 t/ha. The yields between forage yield and seed yield ($r^2$=0.62$^{**}$) were correlated positively. The value of silage as a forage came over 90 days after flowering in combination with peanut leaf+stem+vice straw+inoculant treatment. The treatment was increased dry matter (DM) yield and neutral detergent fiber (NDF), the coarse protein (CP), and total digestible nutrient (TDN) content of silage in comparing with control (peanut leaf+stem). The pH at the organic matter contents of silage in combination of peanut leaf+stem+rice straw+lactic acid treatment was 5.04 to 5.10, the content of butyric and lactic acid were 3.12 to 4.64%, 2.07 to 7.34%, respectively.y.

• FLOWER RESEARCH JOURNAL
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• v.18 no.3
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• pp.157-164
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• 2010

In Chrysanthemum ${\times}$ morifolium, 30 days of continuous short days (SD) are required for flowering. The effects of alternating short day (SD) - long day (LD) - SD treatments was tested in 5 daisy-like single cultivars, 'Limelight', 'Sunlight', 'Candle Light', 'Firebrand', and 'Twilight', Thee other decorative type cultivars, 'Spirit', 'SunburstSpriit', 'Mandalay', and 'Illini Harvest' was also included. Short day treatment was given for 30 days (control: 30SD) and 5 or 10 LD were interposed following 5 or 10 SD. Different responses were noticed when data from all cultivars were combined, showing that flowering was delayed and the number of ray florets were increased by 5 SD-10 LD-25 SD. The number of ray florets, 40 florets in 'Firebrand' and 60.8 florets in 'Candlelight' was increased significantly by 5 SD-10 LD-25 SD as compared to the control. There were no adverse effects by SD-LD-SD treatment, except for the delay in flowering time from 6 to 7 days. The number of ray florets in 'Illini Harvest' and 'Limelight' were, however, not increased by any SD-LD-SD treatments. Cultivar dependent responses should further be investigated in other newly available cultivars, and this information could be used to breed new cultivars.

• Korean Journal of Medicinal Crop Science
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• v.4 no.1
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• pp.74-77
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• 1996

This experiment was conducted to evaluated the effect of CM (plant growth regulator) treatment on flowering, pod maturing and root yield components of Astragalus membramaceus Bunge. Three dilution rates (60, 70 and 80 times) were sprayed at $3{\sim}4$ leave stage. As the results, flowering was delayed $25{\sim}35$ days than August 13 of control and higher dilution rates was more effective to delay flowering. At the havesting time, be compared with non-treatment, plant height reduced $7.6{\sim}18.9\;cm$ and number of matured pods were decreased $50.6{\sim}76.1$ by increasing dilution rates. However, weight of dry root per plant was increased to 29% and dry root yield per 10a was increased to 28% in dilution rates 70 compared with non-treatment.

• Journal of Physiology & Pathology in Korean Medicine
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• v.18 no.2
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• pp.359-370
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• 2004

Before the current western medicine was spreaded out in the world as the main stream, each country had treated diseases with the medicine of their own and the traditional medical books, which are so characteristic, are handed down. Considering the earnest assignment to do in Korean medical of this age and one of the tendencies of medical circles in the world is putting together the current medicine with the traditional medicine, the production and spread of the classification system for the technical books which is contained the characteristic of traditional chinese medicine, the present condition of modern chinese medicine, and the future of it, must be settled without delay. The classification system for oriental medicine section developed in the range of the simple system before the time of flowering, since then the western medicine had grew as the main current in medicine in Korea. But until now the rational and realistic classification system based on the changeable time isn't be established, so setting up one of the classification systems for medicine section, it is classified according to the principle of classification system for medicine section. Hereupon, the result was made after researching the changes of modern classification system for korean and studying on the changes of classification system for oriental medicine section of the Korean decimal classification.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.25 no.4
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• pp.1-9
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• 1980

To determine the optimum harvest time of recent rice varieties from Indica/Japonica remote crosses, leading varieties Suweon 264 and Milyang 23 were tested for the changes in dry matter weight and moisture content of grain, shattering, shelling ratio, milling ratio, and apparant physical quality during grain development at 5 day-intervals from 20 days to 55 days after heading. The results are summarized as follows: 1. Grain weight (dry matter) reached its maximum (physiological maturity) at 30 days after flowering (DAF) in Suweon 264, and at 35 days in Milyang 23, and thereafter it did not change significantly until 55 DAF. 2. Time course of decrease in grain moisture content (Y, %) during maturation (X, DAF) consisted of two linear phases, i.e. a fast and a slow period: Y=68.245-1.33X until 34DAF, and Y=23.025-0.470X until 55DAF after 34DAF in Suweon 264; Y=73.62-1.634X until 24.5DAF, and Y=33.59-0.570X until 55DAF after 24.5DAF in Milyang 23. Two varieties showed the same grain moisture content of 28% (wet basis) at physiological maturity in spite of the distinct differences in the heading date, time of physiological maturity and thereby ripening climate. 3. Force to shatter a grain ranged about 90 to 100g in Milyang 23, and about 200 to 250g in Suweon 264 and in a Japonica variety, Jinheung. The force, however, did not change significantly with harvest time from 35DAF to 50DAF. 4. The changes in the ratios of shelling, milling, broken rice and tinted rice with harvest time were insignificant during a period from 35DAF to 55DAF. However, ratios of green rice and white belly rice decreased significantly with delay in harvest time during 10 days after physiological maturity. 5. The best time of harvest for maximum yield and good quality is thought to be 10 days after physiological maturity, and grain moisture content at this time was about 20% on wet basis.