• Korean Journal of Medicinal Crop Science
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• v.4 no.3
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• pp.187-192
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• 1996

This study was investigated to know about the stages of flower bud development and the effects of natural and artificial cold treatment on flowering of herbaceous peony. Developing buds of Paeonja lactㅑflora Pall. var. Taebaek were observed since Jun. 17 and peony plants were forced since Nov. 27 in the green house with two weeks interval, and other plants were forced after cold treatment in $5^{\circ}C$ for 1, 2, 4, 6weeks. Differentiation of vegetable part in peony buds was started in early June, and floral part was differentiated in September and their differentiation was continued to shooting in early spring. Buds of peony were sprouted and flowered when it was forced on Dec. 4. Days to shooting were decreased with delay of forcing time from early to late of December, significantly. Two weeks for cold treatment were enough to break dormancy of peony and days to shooting of the cold treated were significantly shorter than the untreated in the same forcing times

• Journal of Bio-Environment Control
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• v.23 no.4
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• pp.263-268
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• 2014

This research was performed to investigate the effect of light source and light quality in night break treatment on the growth and flowering of standard chrysanthemum. It was processed 4 hours (22:00-02:00) night break using LED 590, 610, 630, 660, 680nm and fluorescent lamp (mixed light of 480+540+610nm) in standard chrysanthemum 'Baekma' and 'Jinba' for 40 days from transplanting. The days to flower budding from short-day treatment of 'Baekma' were the longgest at fluorescent treatment (21.3 days) and were the shorttest at LED 590nm treatment (15.8 days) among all treatments. The days to flower budding from short-day treatment of 'Jinba' was longger with 18.0 days, 17.8 days, and 17.7 days at the fluorescent, LED 610nm, and 660nm treatments. And it was the shortest with 15.1 days in LED 590nm treatment. Similarly, the days to flowering from short-day treatment of 'Baekma' was the longgest with 56.9 days at fluorescent treatment, and was the shorttest in 51.6 days about LED 590 nm treatment. The days to flowering from short-day treatment of 'Jinba' was longer at fluorescent (56.0 days) and LED 660nm (56.7 days) treatments and was shortest at LED 590nm (52.9 days) among all treatments. Therefore, inhibition of flower bud initiation and flowering were the most effective under fluorescent treatment in case of 'Baekma', and fluorescent and LED 660nm treatments in case of 'Jinba'. The length and weight of cut flower of 'Baekma' and 'Jinba' were most excellent in fluorescent treatment in which the floral differentiation suppression effect was the best. Consequently, as to the growth and flowering of standard chrysanthemum, the treatment which was suitable as the light source and light quality for night break is regarded as the fluorescent lamp, and also under LED 660nm up to a certain level.

• Journal of Bio-Environment Control
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• v.28 no.2
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• pp.178-184
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• 2019

Strawberry ($Fragaria{\times}ananassa$) is one of the most important and popular fruit crops in the world, and 'Sulhyang' is one of the principal cultivars cultivated in the Republic of Korea for the domestic market. The growth and flower induction in strawberry is the process which influences directly on fruit bearing and yield of this crop. In this study, effect of benzyladenine (BA), gibberellic acid ($GA_3$), and salicylic acid (SA) on growth and flower bud induction in strawberry 'Sulhyang' was investigated. The 3-week-old runner plants, grown in 21-cell propagation trays, were potted and cultivated in growth chambers with $25^{\circ}C/15^{\circ}C$ (day/night) temperatures, 70% relative humidity (RH), and light intensity of $300{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ photosynthetic photon flux density (PPFD) provided by white light emitting diodes (LEDs). The runner plants were treated with one of three concentrations, 0 (control), 100, and $200mg{\cdot}L^{-1}$ of BA, $GA_3$, or SA solution. The chemicals were sprayed two times on leaves of runner plants at an interval of two weeks. After 9 weeks the results showed that the application of all chemicals caused reduction of root length and chlorophyll (SPAD) content as compared to the control. The lowest chlorophyll (SPAD) content was recorded in plants treated with $GA_3$. However, the treatment of $200mg{\cdot}L^{-1}$ $GA_3$ promoted leaf area, leaf fresh weight, and plant fresh weight. The greatest flower induction (85%) and number of inflorescences (4.3 inflorescences per plant) were observed in the treatment of $200mg{\cdot}L^{-1}\;SA$, followed by $100mg{\cdot}L^{-1}\;SA$. Overall, results suggest that foliar application of $GA_3$ solution could accelerate plant growth, while foliar application of SA solution could induce hastened flowering. Further studies may be needed to find out the relationship between $GA_3$ and SA solutions treated in a combination, and the molecular mechanism involved in those responses observed.

• Korean Journal of Plant Resources
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• v.29 no.3
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• pp.331-338
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• 2016

The present study aimed to compare and investigate the morphological characteristics and yield components according to ploidy level of diploid and tetraploid Platycodon grandiflorum under vinyl-greenhouse and open field conditions. Plant height of diploid and tetraploid P. grandiflorum was 51.3 ㎝, 54.0 ㎝, respectively. The results revealed that the plants grown in the vinyl-greenhouse showed significantly higher growth compared to those grown in the open field. Regardless of the growing place, diploid and tetraploid of P. grandiflorum showed the rapid elongation of internodes after 4 and 3 internodes respectively and elongation tends to be decreased as entering the flower-bud differentiation period. The starting day of flowering in vinyl-greenhouse cultivation was found to be faster than that of the open field cultivation by 2∼3 days and tended to be delayed by about 5∼6 days in tetraploid P. grandiflorum compared to diploid. Fresh weight of roots from the vinyl-greenhouse cultivation showed a high quantity as 34.2g and 49.4g in diploid and tetraploid P. grandiflorum, respectively and especially tetraploid P. grandiflorum was found to be increased by approximately 44.4% compared to other plots.

• Journal of Bio-Environment Control
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• v.17 no.3
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• pp.221-225
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• 2008

Lilium formolongi 'Fl August' plantlets with scale-leaves and scale-bulb were treated at 10, 15, 20, $25^{\circ}C$ for 15, 30, or 45 days and planted in February, March, April and May. In the April planting, flowering percentage was below 10% and in the May planting no flowering occurred. Sprouting and flowering percentages were lower at the late planting times. Days to flowering of the April planting was 110.8 days compared to 128 days for the February planting. Plant height and numbers of leaves were reduced to 7.2 in May planting, compared to 40.5 leaves in February planting, and almost no flowers emerged in either the April or May plantings. Plantlets exposed to 10 or $15^{\circ}C$ flowered at 80 percent or higher at all treatment durations, but at 20 or $25^{\circ}C$ flowering percentages were lower, with 30% or less in the $25^{\circ}C$ treatment. In the $15^{\circ}C$ treatment days to flowering were less than 100 days, while the number of flowers and flower bud differentiation were greatest in the $15^{\circ}C$ treatment. Cytokinin and auxin were analyzed in bulblets grown at 15, 20 and $25^{\circ}C$. T-zeatin content was three times greater in the $15^{\circ}C$ treatment than at $25^{\circ}C$, but the content of indoleacetic acid (IAA) was less at $15^{\circ}C$ than at 20 and $25^{\circ}C$. In the $15^{\circ}C$ treatment, T-zeatin content was about twice the IAA content in the scale- bulblet. The auxin and cytokinin balance may affect flower bud differentiation. $15^{\circ}C$ with 30 days was most effective for flowering in scale-bulblet and planting of February and March were effective for flowering too.

• Korean Journal of Agricultural and Forest Meteorology
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• v.3 no.4
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• pp.185-198
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• 2001

This study was conducted to reveal the effects of local climatic conditions on reproductive growth in a mature stand of Korean white pine based on climatic estimates. For this, the reproductive growth such as production and characteristics of cone and seed were first measured and summarized for seven years from 1974 to 1980. The local climatic conditions in the study site were also estimated by both a topoclimatological method and a spatial statistical technique. The local climatic conditions were then correlated with and regressed on the growth factors to reveal the relationships between the climatic estimates and the reproductive growth. Average number of conelet formation per tree showed highly negative correlation with some climatic variables related to minimum temperature in the year of flower bud differentiation. Especially, the most significant negative correlation were found between average of the minimum temperature for June and July of flower bud differentiation year and the number of conelet formation. There was no significant correlation between the number of cone production and climatic variables. However, total precipitation from December of the flowering year to February of the cone production year showed the most high correlation (r=0.6036) with the number of cone production. It was found that significant climatic variables affecting the amount of cone drop and cone drop percentage were the sum of cloudy days from June of the flowering year to August of the cone production year. Positive correlation was significantly recognized between the average weight of empty seed per cone and total precipitation from December of the flowering year to February of the cone production year. For the percentage of empty seed, five climatic variables among 19 variables were significantly correlated at 10% level. The average weight of a cone showed negative correlation with total precipitation from June of the flowering year to August of the cone production year. It was also found that average weight of a seed had highly negative correlation with total precipitation from December of the flowering year to February of the cone production year. The average weight of cone coat was negatively correlated with two climatic variables derived from clear days, which are sum of clear days from November of the flowering year to March of the cone production year and sum of clear days from December of the flowering year to February of the cone production year. On the other hand, it showed positive correlation with mean temperature of May in the flowering year. The exactly same results were obtained in correlation analysis for the percentage of cone coat.

• Horticultural Science & Technology
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• v.35 no.1
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• pp.30-37
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• 2017

This study was conducted to determine the effects of various growth substrates on the growth and flowering of hydroponically grown Freesia hybrid 'Gold Rich'. Perlite, peat moss and a perlite: peat moss mixture (1 : 1 ratio, v / v) were used as the growing media. The greatest plant height before flower bud differentiation was attained using mixed medium compared to the others. The type of medium used did not influence leaf number, mineral content or SPAD value in leaves. Flowering began at 137 days after planting in mixed medium, which was 13 days earlier than in perlite medium. The whole plant fresh weight was 21.3 g heavier in mixed medium than in perlite medium (40.9 g). A similar result was obtained for shoot length, with the highest value (96.6 cm) obtained in mixed medium, i.e., 20 cm higher than in perlite medium (76.6 cm). Floret number per plant was also the highest in mixed medium (14.4), i.e., 1.7 - times higher than in perlite medium. Therefore, among the substrates tested in this experiment, we recommend using mixed perlite: peat moss medium (1 : 1 ratio, v / v) for hydroponic culture of freesia, as the use of this medium improved the physical properties of the plants, producing the best results in terms of plant growth and cut-flower quality.

• Horticultural Science & Technology
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• v.33 no.3
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• pp.448-452
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• 2015

'Seeberry' is a short-day $F_1$ hybrid strawberry for seed propagation, that was released by the Protected Horticulture Experiment Station (RDA, Republic of Korea) in 2013. Inbred lines derived from domestic germplasms and selected varieties were used to develop this cultivar. 'Seeberry' originated from a cross of two inbred lines: a male parent 'Wongyo 3115' with high firmness and a female parent 'Wongyo 3116' with excellent fruit shape and high yield. 'Seeberry' cultivar should be grown with a crown diameter of over 10 mm to reveal its unique characteristics. 'Seeberry' has an upright plant shape with elliptic leaves, 12-15 flowers per cluster, vigorless growth habit, and average flower bud differentiation compared to vegetatively propagated cultivars. Fruits of 'Seeberry' are conical, having light skin color and approximately 15-16 g in average weight. Yield of this cultivar is about 92% lower than that of 'Akihime', but 'Seeberry' has excellent taste, sugar content of $9.7^{\circ}Bx$, acidity of 0.6%, and good texture. With regard to disease and pest resistance, 'Seeberry' is sensitive to powdery mildew, aphids, and the two-spotted spider mite, and is resistant to anthracnose.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.33 no.3
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• pp.215-221
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• 1988

The hop yield prediction model developed based on meteorological elements in Hoeongseong was Y=6,042.846-17.665 $X_1$-0.919 $X_2$-96.538 $X_3$-138.105 $X_4$＋86.910 $X_{5}$ ＋ $X_{6}$ with MS $E_{p}$ of 25.258, $R_{p}$$^{2}$ of 0.9991, R $a_{p}$$^{2}$ of 0.9962 and $C_{p}$ of 7.00. The minimum air temperature at early growing stage ( $X_1$), the total precipitation at cone ripening stage ( $X_2$), the maximum air temperature at flower bud differentiation stage ( $X_3$) and the maximum air temperature at flowering stage ( $X_4$) influenced on hop yield as decrement weather elements. The average air temperature at early growing stage ( $X_{5}$ ) and the total sunshine hours at cone development stage ( $X_{6}$ ) influenced on hop yield as increment weather elements.lements.

• Korean Journal of Plant Resources
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• v.31 no.1
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• pp.90-94
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• 2018

The 'Hongsil' strawberry ($Fragaria{\times}ananassa$ Duch.) is a new cultivar released by Gyeongsangnam-do Agricultural Research & Extension Services in 2015. This cultivar originated from a 2011 cross between '802a312' and 'Okmae' and exhibited suitable fruit characteristics for export due to the high soluble solids content and firmness of the fruit. The breeding line '1116-74-15' was selected as an elite line after examining its characteristics and productivity from 2013 to 2014. A field trial of this line was conducted on a farm in 2015, and it was registered as 'Hongsil' thereafter. The 'Hongsil' strawberry demonstrates intermediate plant type and moderate vigor in growth. It is suitable for forcing culture due to its early flower bud differentiation and low chilling requirement. The soluble solids content of 'Hongsil' is $10.0^{\circ}Brix$, which is approximately $0.4^{\circ}Brix$ higher than that of 'Seolhyang' The Fruit firmness of 'Hongsil' is $13.1g{\cdot}mm^{-2}$, similar to that of 'Maehyang'. Fruits of 'Hongsil' are long conical having a red skin color and marketable yield is $4,269kg{\cdot}10a^{-1}$ which is 16% higher than that of 'Maehyang'. The 'Hongsil' cultivar is sensitive to powdery mildew, and it therefore warrants further investigation regarding disease control.