• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.2
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• pp.123-133
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• 1992

This study was conducted to clarify progressed changes of plant types and the effects of the physiological and ecological components on improving ideotype of winter wheat. 12 wheat varieties were planted at the experimental farm of Wheat and Barley Research Institute in Suwon in 1990. As results of intensive wheat breeding for early maturity since 1959, heading, flowering and maturing dates have been shortened by 17, 15 and 14 dagys, respectively. The shortened days from sowing to heading and from heading to flowering contributed to the early maturity to improved. Physiological factors associated with heading time of wheat could be reprsented by growth habit, photoperiod responses, earliness in narrow sense and winter hardiness. For improving an early maturity of winter wheat, it would desired to maintain some degree of winter habit(III-IV), and recombination of more insensitivity to short day length and more shortened earliness in narrow sense than that of Saemil and Chugoku 81, and higher degree of winter hardiness. For improving the early maturity the more effective way must be of shortened days from sowing to heading, and days from flowering to maturity than days from heading to flowering. Ideotype of wheat will be desired to recombine two semi-dwarf genes with erect plant type being about 70-80cm, less stem elongation by late spring, long spike and many grains per spikelet. Average spike weight ratio was about 45-49% in high-yielding varieties, stem fresh weight was lighter, but spike fresh weight was heavier in new one while leaf fresh weight was similar to each other during the maturing periods. Average spike dry weight ratio was higher about 40～48%, and stem and leaf blade dry weights were lower in the newly bred varieties. Stem dry weight was heavier than spike or leaf dry weight in the old varieties of Yungkwang, Jangwang and Jinkwang. Leaf area index for the varieties showed normal distribution curve as the maximum point in booting stage. The maximum point of this curve come in early maturing wheat, and late in old one. The maximum points of LAI were 6.4～6.8 in the high-yielding varieties. Totals of LAI in each period investigated of old one were higher than those of newly bred being 24.6～28.8. Chlorophyll content of the high-yielding varieties of Chokwang, Geurumil and Saemil as higher than that of the old varieties Jangkwang, Jinkwang, Wonkwang and Sinkwang from regrowing period to April 21. after then slightly and even after heading. Net assimilation rate (NAR) was higher in high-yielding varieties with good plant type, and lower in old ones. Grain yield of the newly released varieties increased rapidly but slowly in the old ones. Change in water content of grain at the growing stage in newly bred was lower than that of the old bred. Diminishing rate of water content of grain in establishment per day was 1.2% average that of the old varieties including Yungkwang was 1.5%, and those of the newly bred including Chokwang were 0.9～1.1%. Chokwang, Naemil, and Saemil were the highest-yielding varieties of the Korean cultivars. Yields were increased by spikes per m$^2$, grain weight for the varieties bred in Suwon, and by spikes per m$^2$ for the varieties bred in Milyang.

• Journal of The Korean Society of Grassland and Forage Science
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• v.5 no.2
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• pp.106-110
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• 1985

This trial was carried out to find out the optimum ridge and seeding rate for the seed production of Festuca arundinacea S. (variety Alta). It was composed of three ridge level (12, 18 and 24cm) and four seeding rates (10, 15, 20 and 25kg/ha) in a split-plot design with 4 replications. The experiment lasted from September 1979 to October 1981. 1. The beginning of heading state was May 12 and the date of full flowering stage was June 2. The optimum stage for the seed harvesting of Festuca arundinacea was about 43 days after beginning of heading stage. 2. The number of panicles were 157 per square meter from the best treatment 18cm ridge with 15kg seed/ha. And the 1000 grain weight was 2.79g for the treatment 12cm ridge with 10kg seed/ha. 3. The average seed yield for two years was 681kg/ha and the largest 831kg/ha for the treatment 18cm ridge with 25kg seed/ha. 4. the average germination rate of the harvested seed was 90.7 percent, and it showed a little higher germination rate from the lower level of seeding rate. 5. The average total DM production with two cuttings of aftermath was about 6715kg/ha. According to the increasing seeding rate and narrowing the ridge, DM yield was higher.

• Korean Journal of Medicinal Crop Science
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• v.2 no.1
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• pp.20-25
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• 1994

This study was carried out to investigate the effect of temperature and daylength on the bolting of Angelica gigas Nakai for decreasing the rate of bolting.Seedlings were transplanted on early December to the PVC pot(1 /1000) in the greenhouse con­trolled the temperature of 15, 20 and $25^{\circ}C$, and the daylength of 8, 12, and 16hrs. Growth of aerial parts, bolting rate and root characteristics of A. gigas were investigated. Seedlings of A. gigas untreated with low temperature were nomally emerged, bolted and flowered in maturing stage. In this results, it was assumed that A. gigas was low sensitive to low temperature. The early growth stage was good at $20^{\circ}C\;and\;25^{\circ}C$, but the late growth was effective at $15^{\circ}C\;and\;20^{\circ}C$. The bolting rate was the highest at $20^{\circ}C$ while the root weight was the lowest. Although the bolting rate was high at $15^{\circ}C$, the yield was increased by the delay of bolting and flowering stage. The bolting rate was increased in the longer daylength and showed more sensitive to the daylength condition than to the temperature. Thus, A. gigas cultivated in gully field with cool temperature or under the shading light could be reduced could the bolting rate.

• Journal of Bio-Environment Control
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• v.22 no.1
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• pp.13-18
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• 2013

This study was conducted to examine the effect of temperature and relative humidity (RH) that might affect the pollen germination rate and pollen tube length in oriental melon. The experiment was performed using three cultivars namely 'Mallijangseong', 'Ohbokggul', and 'Joeundae' wherein environmental conditions were controlled by three different temperatures $15^{\circ}C$, $25^{\circ}C$, and $35^{\circ}C$ and also three RH levels 30%, 60%, and 90%. Based on the results in terms of temperature, true to all cultivars, plants exposed to $25^{\circ}C$ had the highest pollen germination rate while plants exposed to $15^{\circ}C$ had the lowest. Among the three cultivars, 'Mallijangseong' had the highest in terms of pollen germination rate, followed by 'Ohbokggul', and lastly was 'Joeundae' that showed the lowest germination rate. In the case of pollen tube length, pollen exposed under $35^{\circ}C$ showed the longest tube length, followed by pollen under $25^{\circ}C$, and pollen under $15^{\circ}C$ remarkably had the shortest tube length. Across the three cultivars 'Ohbokggul' had the longest pollen tube length. In the case of RH, pollen germination response among three cultivars depends on the humidity conditions but based on the results, there was no significant differences although high germination rate was observed in highest humidity condition. Between each cultivar, 'Ohbokggul' had the lowest pollen germination rate compared with 'Mallijangseong' and 'Joeundae' after exposure to different RH conditions wherein pollen germination showed significant differences among treatments. The pollen collected under 60% RH had the longest pollen tube length, followed by 30%, and the shortest was under 90% RH. In general, 'Ohbokggul' had the longest pollen tube length while 'Joeundae' had the shortest among the three cultivars.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.1
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• pp.44-49
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• 2003

In vitro culture of panicle has been the method to accumulate starch and protein in immature grains by providing nutrients after florets crossed between remote genotypes artificially. Grain filling means embryo development and sucrose translocation from photosynthetic source, and starch manufacture in endosperm. The concentrations of sucrose used to culture immature rice panicle were 5, 10, 15, 20% and glutamine was 20 mM. When immature rice panicles at 5 days after flowering were cultured in distilled water with different concentrations of sucrose, glutamine 20 mM and MS medium with different concentrations of sucrose, glutamine 20 mM for 30 days the later was effective on grain filling. The optimal concentration of sucrose on grain filling in vitro culture of rice panicle was 10% and the weight of grain cultured was 10.14 mg that was corresponded to 57% of intact plant. In the method of treating plant growth regulators, the culture of immature rice panicle adding in MS medium with Kinetin, IAA, $\textrm{GA}_3$ were effective on grain filling than the culturing of immature rice panicle after submerging in solutions of Kinetin, IAA, $\textrm{GA}_3$ for 1day. When immature rice panicle was cultured in MS medium with sucrose 10% and Kinetin 46.47 $\mu$M it was effective on grain filling, respectively. The weight of grain cultured was 13.1mg that was corresponded to 75% of intact and germination rate was 51 %. When immature rice panicles were cultured in medium with different concentrations combined with Kinetin 4.65, 46.47, 464.7 $\mu\textrm{M}$, IAA 5.71, 57.08, 570.80 $\mu\textrm{M}$ for 30 days and in medium with IAA 5.71, 57.08, 570.80 $\mu\textrm{M}$ for 15 days after culturing in medium with Kinetin 4.65, 46.47, 464.70 $\mu\textrm{M}$ for 15 days the effect on grain filling was similar.

• Journal of The Korean Society of Grassland and Forage Science
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• v.43 no.3
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• pp.156-161
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• 2023

This study was conducted to determine the appropriate seeding dates by verifying the difference in winter survival and productivity of alfalfa according to fall sowing dates in the central area of South Korea. The experiment was conducted for 2 years (2020 and 2021) at the field in the Department of Animal Resources Development, NIAS located in Cheonan. Sowing dates started from September 18 to November 8 with 10 days of intervals during 2020 and 2021; SO1 (September 18), SO2 (September 28), SO3 (October 8), SO4 (October 18), SO5 (October 28), and SO6 (November 8). After sowing, the winter survival rate was measured in the spring of the following year, and the dry matter yield was measured by harvesting at 10% flowering and harvesting five times a year. SO6 failed to winter survival, and SO5 also had a lower winter survival rate than SO1~4 (p<0.05). The average annual dry matter yield of alfalfa linearly decreased with delaying sowing dates (p<0.05). The feed value did not differ in the same year by delaying the sowing date in the same year. These results suggest that sowing date should be started before October 18 to increase winter survival and productivity of alfalfa in the central area of South Korea.

• Korean Journal of Medicinal Crop Science
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• v.15 no.3
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• pp.152-156
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• 2007

The Condonopsis lanceolata Trautv. was planted in field to investigate the effect of afterwards shading in the condition of sun light of fifty six percent on the characteristics of photosynthesis according to leaf position at flowering stage. The vine length and leaf area were increased with shading treatment in comparison with that of non-shading. Dry weight of leaf and vine indicate opposite tendency with the result above. SLA (specific leaf area) was much more increased in shaded leaves than that obtained from non-shading treatment. The shaded leaves of plant show a higher SPAD value than that of non-shaded leaves. The net photosynthetic rate and stomatal conductance were increased as the PAR was increased. And it is the maximum valve (PAR of 700-1000 ${\mu}$mol/m$^2$/s of PAR) of all leaves. Overnurse and light saturation point of the Condonopsis lanceolata Trautv. shading-treated was improved in comparison with control as net photosynthetic rates of leaves positioned on each part of the stem was increased.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.4
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• pp.331-336
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• 2004

Changes in the level of metabolites in leaves and pods were examined with respect to the seed chemical composition in black soybean. There was no further increase in pod length after 42 days after flowering (DAF). Pod weight, however, persistently increase until 73 DAF, thereafter the weight was slightly lowered. The seed storage protein, however, increased drastically as the increasing rate of pod weight was lessened at 61 DAF. The accumulation of seed storage proteins was occurred conspicuously as the increasing rate of pod weight was slowed down. The chlorophyll content both in leaves and pods was drastically decreased after 50 DAF. The beginning of drastic reduction in chlorophyll content was occurred concomitantly with the reduction of soluble protein content in leaves. The sugar content in leaves showed similar tendency with chlorophyll and soluble protein content. The starch level in leaves, however, showed different changing pattern during seed development. The starch content in leaves was increased persistently until 66 DAF, thereafter the content was decreased drastically to about $55\%$ of maximal value at 66 DAF. Total phenolics content in leaves and the anthocyanins content in seeds were stable without noticeable increase until 66 DAF. The contents were increased dramatically after 66 DAF showing the synchronized pattern with the decrease in starch level in leaves. The levels of the selected metabolites in leaf and seed suggested that the accumulation of chemical components of black soybean seed is launched actively at 66 DAF. The profile of storage proteins was nearly completed at 61 DAF because there was no large difference in densitometric intensity among protein subunits after 61 DAF. In soybean, chemical maturation of seed begins around 61 to 66 DAF at which most metabolites in vegetative parts are decreased and remobilized into maturing seeds.

• Korean Journal of Medicinal Crop Science
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• v.27 no.3
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• pp.167-172
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• 2019

Background: Angelica acutiloba Kitagawa belongs to the flowering plant family Apiaceae. Its young leaves are consumed as a vegetable, and its roots have medicinal properties. This study was conducted to analyze the seed germination characteristics of A. acutiloba according to its ripening stages. Methods and Results: The seeds were harvested from a research farm managed by the Department of Herbal Crop Research, Rural Development Administration in 2018 and were divided into six groups according to their specific gravities. In particular, we studied the effect of harvesting periods and umbel orders on seed characteristics. The results showed that the rates of germination, emergence, and early growth improved as the specific gravity of the seeds increased. In addition, the germination rates of the seeds harvested in mid July and early August were significantly higher than those harvested in the other seasons, and the seeds obtained from the first floret had the greatest mass and weight. Conclusions: In this study, we demonstrated that it is possible to improve the germination rate by appropriate selection of seeds and harvesting period both of which are closely related to seed maturity.

• The Korean Journal of Ecology
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• v.12 no.3
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• pp.171-182
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• 1989

The structure, clonal grwoth, shoot modules dynamics and rhizome respiratory rate of the Phragmites longivalvis circular patch were studied in a 15-year-old reclaimed land on Mado of the western Korea for two growing seasons. Clonal growth by P. longivalvis resulted in subpopulations of shoot modules which may be separated into pioneer, mature and senile growth phase. The radial growth of circular patch was 208 cm per a year. The shoot phytomass, shoot height and spike frequency were the lowest in the senile phase, and were the highest in the mature phase. The maximum shoot phytomass of pioneer, mature and senile phase in August was 347, 536 and 195g/$\m^2$ for the first year, and 609, 748 and 248g/$\m^2$ for the second year, respectively. The birth rates of shoot modules were the highest during the early spring. Of all modules, the percemtage of spring cohort of pioneer, mature and senile growth phase were 52, 82 and 70% for the first year, and 83, 88 and 85% for the second year, respectively. The flowering shoots were only derived from spring cohorts. The death rates of shoot modules of the pioneer and mature phase were the highest in October. The module is an annual semelparous plant though the genet is a perennial iteroparous plant. Their survivorship curve was negatively (Deevey type I). The density of shoot modules of the pioneer, mature and senile growth phase increased as much as 4.0, 1.6 and 2.3 times for one year, respectively. The respiratory rate was the highest in the lowest in the senile growth phase.