• Horticultural Science & Technology
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• v.18 no.3
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• pp.391-394
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• 2000

Girdling and girdling+pinching treatments on 'Sekaiichi' apple remarkably reduced June drop and accelerated fruit growth in early stage of fruit development. Girdling+pinching and pinching reduced bourse shoot growth compared with non-treated control. There were no significant differences in flower bud formation in the following year among treatments. It was assumed that the optimum period for girdling is between 5 days before full bloom and full bloom period.

• Journal of Ginseng Research
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• v.13 no.1
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• pp.79-83
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• 1989

This study was conducted to determine the effect of growth regulators, IBA, GA, and BA, on the adventitious bud formation, shoot differentiation, and inflorescence development in embryo culture of Korean ginseng. The adventitious bud formation and shoot differentiation were significantly promoted by application of a combination of 1 ma/l IBA and 5 mg/l GA. The adventitious buds had the primordial shoots and were differentiated as to plantlets. About 5 to 10 adventitious buds developed around the basal axis of the epicotyle of the ginseng embryo, and development of inflorescence was possible only after shoot differentiation. The MS medium supplemented with a combination of 3 mal 1 each of IBA, GA, and BA was most effective for in vitro inflorescence development, and the ratio of inflorescence formation was 18.4%.

• Journal of Forest and Environmental Science
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• v.34 no.6
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• pp.435-450
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• 2018

Phenological events of four Rhododendron tree species (viz. R. arboreum, R. arboreum ssp. delavayi var. delavayi, R. barbatum and R. kesangiae) was monitored in temperate mixed broad-leaved forests of Arunachal Pradesh, India. Phenological events like flower bud formation, flowering, fruit setting, fruit maturing, seed dispersal, leaf bud formation, leaf flushing, and leaf shedding were recorded. Indices i.e., phenophase sequence index (PSI), active phenophasic period of the species (APS) and index of reproductive/vegetative activity (RVA) were also calculated. Present study revealed that bark consistency, growth form and leaf pattern of the studied species have showed variations among the species. Rhododendron species exhibited the phenological events overlapping with other phenophases. The peak flower bud formation was observed during the winter; R. arboreum ssp. delavayi var. delavayi start flowering from December, while the flowering in rest three species exhibited during February to April. Fruit setting occurred during summer to autumn while fruit maturation revealed peak during November. Leaf bud formation illustrated two peaks in April and May, leaf flushing exhibited peak in June, while leaf shedding peaked during October to November. Active phenophasic period of the species were found 12 months, which revealed that species engage in various phenophase activities throughout the year. Phenophase sequence index ranged between 0.8 to 0.9 (PSI ${\geq}0.6$), signifies that species have a sequential arrangement of phenophases. Index of reproductive/vegetative activity of the species exemplified >1, indicate that the reproductive phenophases were dominance over vegetative phenophases. The study have provided substantial insight on the life cycle events of Rhododendron species and ecological approaches for further scientific study with recent climate change and effective management and conservation.

• FLOWER RESEARCH JOURNAL
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• v.19 no.2
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• pp.96-102
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• 2011

The objective of study was carried out to find a proper entrance date for breaking dormancy depending on cutting and entrance date into greenhouse investigating plant growth and flowering characteristics of chrysanthemum 'Baekma'. Days to visible bud formation and days to flowering were increased as cutting date was delayed. The flowering rate of cutting on September 18 was 100% while cutting on October 30 did not induce flower bud formation. Flower characteristics were surveyed after 'Baekma' and 'Jinba' rooted cuttings were planted on September 10. Branching formation rate of 'Baekma' was gradually increased as entrance date was delayed while that of 'Jinba' was about 70-80% regardless of entrance date. Lethality of 'Baekma' moving into greenhouse on December 20 was 1.5% by cold injury. 'Jinba' started to die on November 10 by cold injury and lethality of 'Jinba' moving into greenhouse on December 20 was 21.7%. Thus, lethality of 'Jinba' was about 5-14 times higher than that of 'Baekma'. Days to visible bud formation and days to flowering were decreased as entrance date was delayed in chrysanthemum 'Baekma'. Days to visible bud formation of entrance date on November 10 and December 10 were 67.9 and 50.3, respectively. On the other hand, that of 'Jinba' was increased until entrance date on December 10 and decreased on December 20. Based on these results, it was suggested that dormancy of 'Baekma' was started at late September and completed at late October.

• Horticultural Science & Technology
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• v.33 no.2
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• pp.202-209
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• 2015

In this study, we investigated the cumulative effect of low temperature on bud dormancy release and bud break characteristics in 'Campbell Early' grapevine (Vitis labruscana B.) cuttings grown in water culture. Additionally, we observed the development of buds while exposed to low temperatures in an attempt to improve our understanding of dormancy and bud break. The shoots were collected 120 days after full bloom (DAFB; leaf abscission period), and the accumulated chill unit (CU) value was calculated by reducing the temperature to $7.2^{\circ}C$ at 125 DAFB. The rate of bud break was 100% in shoots collected at 150 DAFB, The period until the first bud break was two times longer than in the shoots collected 165 DAFB, and bud break speed was significantly reduced. These results indicate that buds are released from endodormancy after 165 DAFB, because at this point the bud break was complete (bud break rate 100%) and it occurred in a very short time period. During this period, when the low-temperature accumulated value was 321h and 442CU according to the CH and Utah models, respectively. Furthermore, the survival rate of main buds decreased rapidly after 165 DAFB, and survival rate of accessory buds was maintained at more than 90% without seasonal differences. The rate of flower bud formation of main buds was much higher than in accessory buds (1:0.23) before the release from endodormancy at 150 DAFB. The final ratio of accessory buds to main buds was high, 1:1.54, at 255 DAFB. Correlation analysis of each investigated factor revealed that bud survival rate and bud formation rate were related only for the main buds, and there was a close relationship between the survival rate of main bud and time. In addition, the survival rate of main buds was positively correlated to the rate of flower bud formation.

• Journal of Korean Society of Forest Science
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• v.57 no.1
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• pp.45-51
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• 1982

The environmental influence on cone crop of Pinus koraiensis has been studied by means of correlation and regression analysis of number of 1-year-old cone and meteorological data. A positive effect on cone crop is brought about by low air temperature during the year of flower bud differentiation and much sunshine duration for the year and the winter before flower bud differentiation. The weather of June before flower bud differentiation is very important for cone production.

• Journal of Ginseng Research
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• v.33 no.1
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• pp.65-71
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• 2009

This experiment was done to determine the optimum conditions for the induction of tetraploidy in Panax ginseng C. A. Meyer using bud length, temperature and plant growth regulator pretreatments. Highest callus formation was obtained when the medium was inoculated with flower bud in the size of 2-3 mm in length. The optimum temperature for the callus formation was high when treated at $4^{\circ}C$ for 4-5 days. Among the treatments of growth regulators and different concentration, highest callus formation was observed in combination of 5 mg/L 2,4-D and 1 mg/L kinetin for P. ginseng. As a result of flow cytometer analysis, all 7 adventitious roots were confirmed as tetraploidys. Cytological analysis revealed that the chromosome number of tetraploid roots was 96, while that of diploid roots was 48. Tetraploid ginseng roots were inoculated to flower bud size of 2-3 mm in length. The callus formation was optimum when treated with 1 mg/L 2,4-D at $4^{\circ}C$ for 5 days. Compared with control roots, tetraploid roots were thicker and longer and had few lateral branches. Fresh weight of tetraploid roots was relatively higher than the control roots.

• Korean Journal of Medicinal Crop Science
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• v.11 no.2
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• pp.97-101
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• 2003

The purpose of this experiment is to improve the ratio of female flower in Schizandra chinensis Baillon. The experiment was carried out in two purposes. One was to understand the development stages on bud formation and determining sex after bud formation by stage. The other was to investigate characteristics of flowers forming on spring when summer pruning was taken place in different cutting part and timing in S. chinensis Baillon. The outcome was that on 7th of June the flower bud was found next to leaf primordium in branch of this year and no changes were found in shape for two weeks by 26th July. On 26th of June, an ovule that forms organ was observed and then, an ovule was found after sex was determined on 6th of July. Second experiment was carried out to find out when the sex was determined by adapting different pruning methods; cutting the branch at 6th node on June 1, June 15, and July 1; cutting the branch at 10th node on June 15, and July 1. The result was that the re-growth ratio on the branch 6th node was cut on June 1 and June 15. July 1 was 34-56% and, however, the number of setting flowers and mail flowers were fewer than the normal branches. More over, even though the re-growth ratio of branches were 34-25% when the cutting was taken place at 10th node on June 15 and July 1, the number of setting flowers and mail flowers were the same as the non treated branch. As a result, it is assumed that cutting controlling in this plant to increase the number of female flowers has no effect.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.26 no.1
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• pp.69-89
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• 1981

Stevia (Stevia rebaudiana Bertoni) is a perennial herb widely distributed in the mountainous area of Paraguay. It belongs to the family Compositae and contains 6 to 12 percent stevioside in the leaves. Stevioside is a glucoside having similar sweetening character to surgar and the degree of sweetness is approximately 300 times of sugar. Since Korea does not produce any sugar crops, and the synthetic sweetenings are potentially hazardous for health, it is rather urgent to develop an economical new sweetener. Consequently, the current experiments are conducted to establish cultural practices of stevia, a new sweetening herbs, introduced into Korea in 1973 and the results are summarized as followings: 1. Days from transplanting of cuttings to the flower bud formation of 6 stevia lines were similar among daylengths of 8, 10 and 12 hours, but it was much greater at daylengths of 14 or 24 hour and varietal differences were noticable. All lines were photosensitive, but a line, 77013, was the most sensitive and 77067 and Suweon 2 were less sensitive to daylength. 2. Critical daylength of all lines seemed to be approximately 12 hours. Growth of plants was severely retarded at daylengths less than 12 hours. 3. Cutting were responded to short daylength before rooting. Number of days from transplanting to flower bud formation of 40-day old cuttings in the nursery bed was 20 days and it was delayed as duration of nursery were shorter. 4. Number of days from emergence to flower bud formation was shortest at short day treatment from 20 days after emergence. It was became longer as initiation of short day treatment was earlier or later than 20 days. 5. Plant height, number of branches, and top dry weight of stevia were reduced as cutting date was delayed from March 20 to May 20. The highest yield of dry leaf was obtained at nursery duration of 40-50 days in march 20 cutting, 30-40 days in April 20 cutting, and 30 days in May 20 cutting. 6. An asymptotic relationship was observed between plant population and leaf dry weight. Yield of dry leaf increased rapidly as plant population increased from 5,000 to 10,000 plants/10a with a reduced increasing rate from 10,000 to 20,000 plants/l0a, and levelled off at the plant population higher than 20,000 plants/l0a. 7. Stevia was adaptable in Suweon, Chengju, Mokpo and Jeju and drought was one of the main factors reducing yield of dry leaf. Yield of dry leaf was reduced significantly (approximately 30%) at June 20 transplanting compared to optimum transplanting. 8. Yield of dry leaf was higher in a vinyl house compared to unprotected control at long daylength or natural daylength except at short day treatment at March 20. Higher temperature ill a vinyl house does not have benefital effects at April 20 transplanting. 9. The highest content of stevioside was noted at the upper leaves of the plant but the lowest was measured at the plant parts of 20cm above ground. Leaf dry weight and stevioside yield was mainly contributed by the plant parts of 60 to 120cm above ground but the varietal differences were also significant. 10. Delayed harvest by the time of flower bud formation increased leaf dry weight remarkably. However, there were insignificant changes of yield as harvests were made at any time after flower bud formation. Content of stevioside was highest at the time of flower bud formation and earlier or later harvest than this time was low in its content. The optimum harvesting time determined by leaf dry weight and stevioside content was the periods from flower bud formation to right before flowering that would be the period from September 10 to September 15 in Suweon area. 11. Stevioside and rebaudioside content in the leaves of Stevia varieties were ranged from 5.4% to 14.3% and 1.5% to 8.3% respectively. However, no definit relationships between stevioside and rebaudioside were observed in these particular experiments.

• Journal of Bio-Environment Control
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• v.17 no.2
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• pp.176-180
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• 2008

In days to calyx-flex stage test, flower development affected by light intensity, light duration and the prevailing temperature. As, 'Jacaranda' variety shorter in under 46 days of flower bud formation and 13 days of calyx-flex stage than the other variety with 'Queen Elizabeth' control variety. About cut flower only 'Grand Vicki Brown' (as within 46 days of flower formation, 13 days of calyx stage and 'Jacaranda', both with shorter plants than the other varieties produced cut flower classified as short and medium-stemmed cut flowers. 'Jacaranda', 'Vicki Brown', 'Golden Times', 'Champagne', 'Osiana', and 'Queen Elizabeth (control variety)' flowered earlier from 46.7 to 50.8 days from pruning. Flower development was likewise faster in all the above mentioned cultivars; while 'Tineke' had significantly delayed flower development reaching calyx-flex stage from 0.5 cm bud size after 51.0 days. The top ten high yielding varieties were 'American Orange', with a net income of P3,081,676.00; 'Yellow Island' with P1,572,874.00; 'Frosty Pink' with P1,085,183.00; 'Champagne' with P980,620.00; 'Coral Pink' with P959,669.00; 'Lara Pink' with P918,444.00; 'Lara Orange' with P714,252.00; 'Grand Gala' with P705,787.00; 'Golden Times' with P806,489.00; and 'Lady X' with P778,060.00 net returns.