• Korean Journal of Agricultural and Forest Meteorology
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• v.8 no.2
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• pp.68-76
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• 2006

A thermal time-based two-step phenological model was used to project flowering dates of Japanese cherry in South Korea from 1941 to 2100. The model consists of two sequential periods: the rest period described by chilling requirement and the forcing period described by heating requirement. Daily maximum and minimum temperature are used to calculate daily chill units until a pre-determined chilling requirement for rest release is met. After the projected rest release date, daily heat units (growing degree days) are accumulated until a pre-determined heating requirement for flowering is achieved. Model calculations using daily temperature data at 18 synoptic stations during 1955-2004 were compared with the observed blooming dates and resulted in 3.9 days mean absolute error, 5.1 days root mean squared error, and a correlation coefficient of 0.86. Considering that the phonology observation has never been fully standardized in Korea, this result seems reasonable. Gridded data sets of daily maximum and minimum temperature with a 270 m grid spacing were prepared for the climatological years 1941-1970 and 1971-2000 from observations at 56 synoptic stations by using a spatial interpolation scheme for correcting urban heat island effect as well as elevation effect. A 25km-resolution temperature data set covering the Korean Peninsula, prepared by the Meteorological Research Institute of Korea Meteorological Administration under the condition of Inter-governmental Panel on Climate Change-Special Report on Emission Scenarios A2, was converted to 270 m gridded data for the climatological years 2011-2040, 2041-2070 and 2071-2100. The model was run by the gridded daily maximum and minimum temperature data sets, each representing a climatological normal year for 1941-1970, 1971-2000, 2011-2040, 2041-2070, and 2071-2100. According to the model calculation, the spatially averaged flowering date for the 1971-2000 normal is shorter than that for 1941-1970 by 5.2 days. Compared with the current normal (1971-2000), flowering of Japanese cherry is expected to be earlier by 9, 21, and 29 days in the future normal years 2011-2040, 2041-2070, and 2071-2100, respectively. Southern coastal areas might experience springs with incomplete or even no Japanese cherry flowering caused by insufficient chilling for breaking bud dormancy.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.14
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• pp.133-137
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• 1973

In order to classify the ecotypical and maturing groups 136 Korean local and 4 Japanese Perilla varieties were sown at Suwon on May 20, 1972, and investigations were made on days to flowering, days to maturing and growth duration. Results obtained were summarized as follows: 1. Ecotype was classified from 6 groups with combination of the long and short duration from sowing to flowering and maturing period. The classified symbols of groups were Ia, Ib, IIa, IIIa, and IIIb. I: long duration. to flowering II: medium duration to flowering III: short duration to flowering a: long duration to maturing b: short duration to maturing Korean local varieties were distributed 3 ecotypes of IIa, IIb and IIIa, however, Japanese varieties did 2 ecotypes of IIa and IIb, respectively. 2. Maturing group was classified from 3 groups with long (I), medium (II), and short (III) growth durations. Korean local varieties belong to II and III groups but Japanese varieties belong to I and II groups, respectively. 3. Three were highly significant positive correlation (0.685) between ecotypical and maturing group. Ecotype was more related with days to flowering and growth duration, however, maturing group was related with days to flowering, days for maturing, and growth duration. Korean local varieties, more distributed into ecotype than maturing group, were attributed to differences of environmental conditions and cultural practices at different provinces.

• Journal of agriculture & life science
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• v.45 no.1
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• pp.49-58
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• 2011

Characteristics of leaf unfolding and flowering of 31 chestnut varieties cultivated in southern Korea was conducted to provide basic data for chestnut varieties improvement. There were slight differences among varieties in leaf unfolding time and leaf unfolding was late in 2010 compared to 2008 and 2009. Leaf unlolding took about 8 days to complete in 2008 and 2009, but that took about two weeks to complete in 2010. In 2008 and 2009, flowering beginning and flowering end of staminate flower occurred in early May and June, those were detained by low temperature of April in 2010. Although pistallte flower in flowering characteristics showed very similar to flowering period of staminate flower, The flowering beginning for pistillate flower was earlier approximately 20 days than for staminate flower.

• Journal of Life Science
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• v.15 no.2 s.69
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• pp.211-214
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• 2005

The studies were conducted to obtain basic informations on inheritance of some quantitative characters in kidney bean (Phaseolus vulgaris L.). Seven parents (Felibon, Renka, Processor, Kaboom, $BO_{22}$, Local variety $\#1$ and Local variety $\#2)$ and $F_1$ hybrids of 21 crosses from a set of diallel cross among varieties were used to estimate combining ability for eight agronomic characters such as days to flowering, days to maturity, stem length, pod numbers per plant, pod length, grain numbers per plant, 100-grain weight and grain weight per plant. General combining ability (GCA) and specific combining ability (SCA) were significantly different among all characters, and values of GCA were greater than those of SCA in all characters except number of grains per plant. In effect of GCA, Felibon expressed high GCA effect for days to flowering and number of grains per plant. Local variety $\#1$ showed high GCA effect for 100-grain weight and stem length. Local variety $\#2$appeared to high GCA effect for 100-grain weight and grain weight per plant. Processor expressed high GCA effect for days to maturity and grain weight per plant. Kaboom showed high GCA effect days to flowering and days to maturity. $BO_{22}$ appeared high GCA effect for all characters except for days to flowering, days to maturity and stem length. In the SCA effect, crosses of Felibonx Renka and Local variety $\#2{\times}Processor$ exhibited in high negative effect for days to flowering. Thus, these crosses were evaluated to useful for breeding early maturing variety. Crosses of breeding high yield variety were considered of $Felibon{\times}Local$ variety $\#1$, $Felibon{\times}Renka$ and Local variety $\#2{\times}BO_{22}$.

• Korean Journal of Plant Resources
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• v.24 no.3
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• pp.292-297
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• 2011

This experiment was carried out to investigate the appropriate chilling requirements for breaking dormancy by treating the dormant plant of Hanabusaya asiatica with low temperature ($4^{\circ}C$) for different time periods. The rates of sprouting and flowering were higher with longer treatment periods at low temperature. In addition, the growth and flowering of the plant were better when it was potted after treatment at a low temperature for 90 days. The abscisic acid levels and polyphenoloxidase activity of the dormant plant increased during the low temperature treatment, reached a climax 90 days and decreased thereafter. The catalase activity was the lowest after the low temperature treatment for 90 days and increased subsequently. The peroxidase activity increased and showed a sharp rise after the low temperature treatment for more than 90 days. Considering the physiological activities of the enzymes, the changes in the abscisic acid levels, and the characteristics of growth and flowering after sprouting of the plant, the appropriate cold periods required for breaking dormancy could be 90 days.

• Korean Journal of Agricultural and Forest Meteorology
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• v.18 no.1
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• pp.42-54
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• 2016

It is highly anticipated that warming temperature resulting from global climate change will affect the phenological pattern of kiwifruit, which has been commercially grown in Korea since the early 1980s. Here, we present the potential impacts of climate change on the variations of flowering day of a gold kiwifruit cultivar, Haegeum, in the Jeonnam Province, Korea. By running six global climate models (GCM), the results from this study emphasize the uncertainty in climate change scenarios. To predict the flowering day of kiwifruit, we obtained three parameters of the 'Chill-day' model for the simulation of Haegeum: $6.3^{\circ}C$ for the base temperature (Tb), 102.5 for chill requirement (Rc), and 575 for heat requirement (Rh). Two separate validations of the resulting 'Chill-day' model were conducted. First, direct comparisons were made between the observed flowering days collected from 25 kiwifruit orchards for two years (2014-15) and the simulated flowering days from the 'Chill-day' model using weather data from four weather stations near the 25 orchards. The estimation error between the observed and simulated flowering days was 5.2 days. Second, the model was simulated using temperature data extracted, for the 25 orchards, from a high-resolution digital temperature map, resulting in the error of 3.4 days. Using the RCP 4.5 and 8.5 climate change scenarios from six GCMs for the period of 2021-40, the future flowering days were simulated with the 'Chill-day' model. The predicted flowering days of Haegeum in Jeonnam were advanced more than 10 days compared to the present ones from multi-model ensemble, while some individual models resulted in quite different magnitudes of impacts, indicating the multi-model ensemble accounts for uncertainty better than individual climate models. In addition, the current flowering period of Haegeum in Jeonnam Province was predicted to expand northward, reaching over Jeonbuk and Chungnam Provinces. This preliminary result will provide a basis for the local impact assessment of climate change as more phenology models are developed for other fruit trees.

• Horticultural Science & Technology
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• v.19 no.4
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• pp.568-573
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• 2001

The effects of foliar spray and soil drench application of triazole chemicals (diniconazole, myclobutanil, difenoconazole, tebuconazole, bitertanol, hexaconazole) on growth and flowering control in zinnia were investigated. For foliar spray application of tebuconazole, diniconazole and bitertanol on 'Dream Land Rose', plant height was decreased but tebuconazole gave the best result for dwarfing. Diameter, fresh and dry weights of flower were markably decreased at high concentration of tebuconazole. However, days to flowering was not affected by chemicals tested. For 'Dream Land Scarlet', plant height was decreased with all chemical treatments. Tebuconazole severely decreased plant height, in particulas. Diniconazole hastened flowering. For soil drench of 'Dream Land Rose', plant height was decreased by diniconazole and mycrobutanil, but diniconazole was more effective for plant height decrease. Flowering was hastened by diniconazole in both 'Dream Land Rose' and 'Dream Land Scarlet'. Plant height of 'Dream Land Scarlet' was decreased by all chemicals tested. Flowering was not occurred at $300mg{\cdot}L^{-1}$ myclobutanil with severe suppression of stem growth.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.69 no.1
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• pp.61-69
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• 2024

Considering the threats of climate change, this study was conducted to investigate the influence of temperature and day-length on soybean growth and yield when sown late in comparison to the optimal sowing time in the southern region of the Korean Peninsula. Sowing was executed in 10-day intervals, including on July 1, 10, 20 and 30 and August 10, considering that the optimum sowing time of the three soybean varieties with different ecotypes is June 20. Emergence rates did not differ significantly between late-sowing and optimal sowing in all ecotypes; however, the number of days to emergence, flowering, and maturity was smaller after late sowing. A multiple-regression approach was used to test the effect of temperature and day length on the number of growing days after late sowing compared to the optimal sowing time. This analysis revealed that the number of days required from sowing to flowering was positively correlated with both day length and temperature, and the number of days from flowering to harvest was positively correlated with day length and negatively with temperature. A multiple regression equation can be calculated as follows: the number of days required from sowing to flowering (Y) = 3.177 + (0.030 × (sum of day length + sum of temperature)), and the number of days required from flowering to maturity (Y) = 20.945 + (0.021 × (sum of day length + sum of temperature)). Multiple growth parameters were significantly correlated with yield components, depending on growing days. Optimal sowing resulted in the best yield, while later sowing decreased yield compared to optimal sowing. To avoid a significant decrease in yield, early-maturing species should be sown by July 20, while late-maturing species should be sown by July 10.

• Atmosphere
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• v.25 no.4
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• pp.693-706
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• 2015

A shift of first fowering date (FFD) of spring blossoms (cherry, peach and pear) over the northest Asia under global warming is investiaged using dynamically downscaled daily temperature data with 12.5 km resolution. For the study, we obatained gridded daily data with Historical (1981~2010), and Representative Concentration Pathway (RCP) (2021~2100) 4.5 and 8.5 scenarios which were produced by WRFv3.4 in conjunction with HadGEM2-AO. A change on FFDs in 21st century is estimated by applying daily outputs of WRFv3.4 to DTS phonological model. Prior to projection on future climate, the performances of both WRFv3.4 and DTS models are evaluated using spatial distribution of climatology and SCR diagram (Normalized standard deviation-Pattern correlation coefficient-Root mean square difference). According to the result, WRFv3.4 and DTS models well simulated a feature of the terrain following characteristics and a general pattern of observation with a marigin of $1.4^{\circ}C$ and 5~6 days. The analysis reveals a projected advance in FFDs of cherry, peach and pear over the northeast Asia by 2100 of 15.4 days (9.4 days). 16.9 days (10.4 days) and 15.2 days (9.5 days), respectively, compared to the Historical simulation due to a increasing early spring (Februrary to April) temperature of about $4.9^{\circ}C$ ($2.9^{\circ}C$) under the RCP 8.5 (RCP 4.5) scenarios. This indicates that the current flowering of the cherry, peach and pear over analysis area in middle or end of April is expected to start blooming in early or middle of April, at the end of this century. The present study shows the dynamically downscaled daily data with high-resolution is helpeful in offering various useful information to end-users as well as in understanding regional climate change.

• Horticultural Science & Technology
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• v.28 no.5
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• pp.895-898
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• 2010

A new light pink spray-mum, 'Noble ND' was bred by crossing 'Mona Lisa', a white anemone type flower, and 'Dark Weldon', a pink anemone type flower in October, 2004. The growth and flowering characteristics were investigated in forcing, natural, and retarding cultures from 2006 to 2007. The 'Noble ND' was a medium-flowering fall-mum with light pink anemone type flower and had 9.2 flowers per stem, with 4.8 cm flower diameter in natural culture. The number of days to flowering and flowers per plant was 57 and 7.4, respectively, in forcing culture of 'Noble ND', whereas the number of days to flowering was 48 in retarding culture.