• Proceedings of the Botanical Society of Korea Conference
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• 1987.07a
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• pp.191-211
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• 1987

Common usage of the concept of juvenility implies that there is one physiological phase, the juvenile phase, which manifests itself in the various morphological and physiological phenomena observed in juvenile higher plants. The juvenile phase is often defined as that time from seed germination until the plant attains the ability to flower regulating such behaviour. This definition precludes plants from flowering in the juvenile phase. It is of major interest, therefore, to identify the physiological controls(Bluehreife) regulating such behavior. The length of the juvenile period in higher plants ranges from one year to over 60 years in different species. The long juvenile period of seedling is the main cause of the long duration of the breeding process. I determined the length of the juvenile period in various plants and its control of phase changes in natural system in relation to factors such as plant size and age, shoot morphology, apex size, root system and phytohormonal and nutritional status is reviewed. From the own experimental and observational evidence available it appears that both hormonal and nutritional factors can be involved in control of juvenility but that a specific juvenile or flowering hormone is not involved. Grafting, ringing, scoring, root pruning and fertilization have been used to accelerate flowering, but in most cases these cultured treatments are only successful on plants that were passed the juvenile phase. It is suggested that there are intrinsic difference between the meristematic cells of the apieces of juvenile and adult shoot, which are thus determined with respect to there development potentialities. The problems associated with the maintenance of the determined state through mitosis are discussed. The properties of transitional forms of Ribes nigrum L. intermediate between the juvenile and adult phase, are descrived and there implications discussed. Analogies are drawn between juvenile phenomena in woody perennials and in herbaceous species.

• Korean Journal of Breeding Science
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• v.41 no.4
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• pp.560-563
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• 2009

A new spray chrysanthemum(Dendranthema grandiflorum) cultivar, "Golden Eye" was developed from a cross between "Rosa" and "Angaesoguk" by selection of seedlings and lines at the Flower Research Institute, Gyeongnam Agricultural Research and Extension Services(ARES) from 2004 to 2008. Its characteristics were investigated three times from 2006 to 2008 under condition of forcing culture in spring and retarding culture in autumn. The natural flowering time of "Golden Eye" was October 23th, and year-round production was possible by day length treatment. This cultivar was yellow in color, single in flower type for the spray type cut flower. Its capitulum was 2.4cm in diameter, and had 23.2 head per stem in autumn. Its ray floret was green central zone. The days to flowering under the short day treatment is about 49 days in spring season, and "Golden Eye" showed the vase life of 25.7 days in autumn. This cultivar was registered for a commercialization in 2008.

• FLOWER RESEARCH JOURNAL
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• v.18 no.4
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• pp.295-298
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• 2010

A new spray chrysanthemum(Dendranthema grandiflorum) cultivar, 'Biz' was developed from a cross between 'S03-117' and 'Angaesoguk' by selection of seedlings and lines at the Flower Research Institute, Gyeongnam Agricultural Research and Extension Services(ARES) from 2003 to 2008. Its characteristics were investigated three times from 2006 to 2008 under condition of forcing culture in spring and retarding culture in autumn. The natural flowering time of 'Biz' was October 26th, and year-round production was possible by day length treatment. This cultivar was white in color, single in flower type for the spray type cut flower. Its capitulum was 3.0 cm in diameter, and had 15.6 head per stem in autumn. Its ray floret was green central zone. The days to flowering under the short day treatment is about 42 days in spring season, and 'Biz' showed the vase life of 24.1 days in autumn. This cultivar was registered for a commercialization in 2008.

• Korean Journal of Breeding Science
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• v.42 no.6
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• pp.606-610
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• 2010

A new cultivars Dendranthema grandiflourm 'Dream Moon' was developed at Gyeonggi-do Agricultural Research and Extension Services (GARES), Korea in 2008. The cultivar 'Dream Moon' was derived from a cross between 'Patra', a spray cultivar with yellow single type, and 'Sei-rosa', a spray cultivar with pink single type in 2005. The cultivar has single type flowers with pink petals. Trial evaluation was conducted from 2006 to 2008 for a shading cultivation in summer and a retarding cultivation in spring. The flowering time of 'Dream Moon' is late October, and year-round flowering is possible by shade or light treatment. The diameter of flower is 56.0 mm. Numbers of flowers per stem and petals per flower are 16.4 and 24.6, respectively. After investing of specific characters from 2006 to 2008, it was finally selected and named 'Dream Moon'. It has resistance to white rust and the vase life is about 20.7days in autumn season.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.32 no.1
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• pp.97-102
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• 1987

The objective was to obtain the basic information for the changes of the alpha-acid content according to days after flowering. altitude and weather of Hoeongseong, Korea. The alpha-acid of hops reached the highest con-tent in sixty one days after flowering, and the optimum time for cone picking was noted as 11-15th August. The altitude for the highest alpha-acid content was 190-260m of Hoeongseong. The year-to-year variations in the alpha-acid content of hops were higher than the altitude variations. The higher alpha-acid content was associated with a higher temperature and more amounts of sunshine in late July. Alpha-acid content and yield had a significant positive correlation.

• Korean Journal of Agricultural and Forest Meteorology
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• v.16 no.4
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• pp.304-308
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• 2014

Accurate prediction of peak bloom dates (PBD) of flowering cherry trees is critical for organizing local cherry festivals and other associated cultural and economic activities. A two-step phenology model is commonly used for predicting flowering time depending on local temperatures as a result of two consecutive steps followed by chill and heat accumulations. However, an extensive computation requirement for parameter estimation has been a limitation for its practical use. We propose a sequential parameterization method by exploiting previously unused records of development stages. With an extra constraint formed by heat accumulation between two intervening stages, each parameter can then be solved sequentially in much shorter time than the brute-force method. The result was found to be almost identical to the previous solution known for cherry trees (Prunus ${\times}$ yedoensis) in the Tidal Basin, Washington D.C.

• Journal of Ecology and Environment
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• v.30 no.2
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• pp.143-149
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• 2007

To certify predictability for the times of phenological stages from cumulative air temperature in springtime, the first times of budding, leafing, flower budding, flowering and deflowering for 14 woody plants were monitored and air temperature was measured from 2005 to 2006 at Namsan. Year day index (YDI) and Nuttonson's Index (Tn) were calculated from daily mean air temperature. Of the 14 woody species, mean coefficient of variation was 0.04 in Robinia pseudo-acacia and 0.09 in Alnus hirsuta. However, mean coefficient of variation was 0.30 in Forsythia koreana and Stephanandra incisa and 0.32 in Zanthoxylum schinifolium. Therefore, the times of each phenological stage could be predicted in the former two species but not in latter three species by two indices. Of the five phenological stages, mean coefficient of variation was the smallest at deflowering time and the largest at budding time. In five phenological stages, mean coefficient of variation of YDI was in the range of $0.11{\sim}0.21$ but that of Tn was in the range of $0.15{\sim}0.26$. Therefore, the former was a better index than the latter. Of the species-phenological stage pair, coefficient of variation of YDI was 0.01 in Acer pseudo-sieboldianum - flower budding and below 0.05 in 11 pairs, whereas the YDIs over 0.40 were 4 pairs comprising of Prunus leveilleana - budding (0.51). Coefficient of variation of Tn was 0.01 in A. hirsuta - budding and below 0.05 in 8 pairs. The Tns over 0.40 were 5 pairs comprising of F. koreana - flower budding (0.66).

• Journal of Radiation Industry
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• v.4 no.3
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• pp.253-257
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• 2010

This experiment was carried out to investigate the effects of gamma-radiation on the rooting, growth, and color mutation in poinsettia. Using 10 poinsettia varieties ('Lollipop', 'Little Peace', 'Happy Day', 'Early Bird', 'Pixy Red', 'Happy Time', 'Heidi', 'Red Bell', 'Clara', and 'Scarlet') bred by National Institute of Horticultural and Herbal Science, 100 Gy of gamma ray was irradiated at the stage of callused cuttings. Four weeks after sticking cuttings in the rooting media, 8 cultivars showed 100% of root formation, but 'Early Bird' rooted 24.4% and even died off during the cutting propagation. After planting rooted cuttings, survival rate until flowering time varied among irradiated cultivars. While 'Pixy Red' and 'Heidi' survived about 98%, 'Clara', 'Happy Day', and 'Early Bird' survived lesser than 30%. All irradiated plants showed remarkably shorter plant height, lesser branch numbers than non-irradiated control plants. Thirty color mutants were obtained among 281 plants survived until flowering time. Nine mutants were complete color mutated branches, whereas 21 mutants were partially color mutated bracts and transitional leaves. Color patterns mutated by 100 Gy of gamma ray were divided into pink, hot pink, light red and spotted (pink spots with red main color). Pink mutants were commonly obtained. Complete color mutants were discovered from 4 plants of 'Pixy Red', 2 plants of 'Red Bell' and 3 plants of Lollipop.

• Korean Journal of Plant Resources
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• v.16 no.2
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• pp.123-129
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• 2003

This study was conducted to determine the germination characteristics, oil contents and fatty acid compositions of the different safflower accessions. The safflower accessions had nearly the same germination period of about 12-13 days and the germination rate was more than 87.5%. Plant height grew until 84 days after seeding. The number of leaves did not increase after 70 days from seeding. The accessions had a difference of six loaves from 17 to 23 loaves. Flowering time had a difference of 11 days from 79 days after planting to 90 days after planting. The Jangsung accession had the shortest flowering time of 79 days after planting. In the characteristics of bearing fruit, the number of branches including main stem are from 4.7 to 8.8. The number of head flowers had nearly the same number of branches which were 4.8-8.9, numbers of seed per head flower were 29.3-49.1 and the weight of 100 seeds were 2.9-3.9 g. The crude fat content was 21.8-33.9％ and fatty acid content was 66.6-77.6% containing mostly linolenic acid. Oeic acid content was 9.2-16.5% and it contained palmitic acid, stearic acid, venin acid, arachidonic acid etc. Results of this study, the accession Jangsung, which had the shortest flowering time and had the most crude fat content, was observed to be the best accession for the breeding of safflower.

• FLOWER RESEARCH JOURNAL
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• v.18 no.1
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• pp.33-37
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• 2010

Effects of cutting time of double flowered Hydragea serrata for. acuminata native to Korea on flowering and growth of following year were investigated in order to develop as a pot plant. Cuttings were carried out every 10th day from April to September in 2008. The cuttings were directly placed in 15 cm diameter pots. Longest plant was obtained from May cuttings and their average heights were 31.7 cm, and followed by April and July cuttings. Plant heights of August and September cuttings were 23.6 cm and 22.0 cm, respectively. In contrast, growth and height of June cutting were abnormally small. Leaf length, leaf width and petiole length of August and September cutting were reduced, but numbers of leaves were not changed. Average flower cluster numbers of May cuttings were 4 flower clusters, and July, August and September cuttings were 3 clusters while only 1 flower cluster per a plant was obtained during June. Biggest diameter of flower crown was observed from May cuttings and the size was 10.3 cm diameter; however, smaller flower crown size was observed after July cuttings. The best overall flower appearance was observed from May cuttings, and the worst was June cuttings. Even though plant height of August and September cuttings were reduced, flowering aspect and ornamental value were normal, but blooming times were retarded according to late cutting time.