• The Plant Pathology Journal
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• v.20 no.3
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• pp.220-223
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• 2004

Most plants of commercial poinsettia cultivars grown from cuttings develop mosaic and chlorotic dot symptoms on leaves. Reverse transcription-polymerase chain reaction (RT-PCR) test showed that they were infected with Poinsettia mosaic virus (PnMV). In a survey of commercially grown poinsettias conducted in Korea, PnMV was detected in ten of ten poinsettia cultivars sampled and in 100％ of 178 samples tested. The virus has isometric particles and about 29 nm in diameter. Crystalline virus particles were observed in cytoplasm of cells of diseased plants by transmission electron microscopy. Nucleotide sequence of coat protein gene of PnMV- Kl showed 97.3％ homology with that of a German isolate. This is the first report on PnMV in Korea.

• Horticultural Science & Technology
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• v.17 no.5
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• pp.581-583
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• 1999

This experiment was conducted to investigate the effects of uniconazole drench treatment on the growth and flowering of poinsettia and to suggest proper application dosage and time. Plant height, branch length, and leaf area were significantly restricted as the concentration of uniconazole increased. Application doses of 0.05 and 0.10 mg/pot effectively controlled the growth of poinsettia 'V-10 Amy'. Earlier soil drench of uniconazole resulted in more effective reduction in plant height, branch length, and leaf area. In all cases, no noticeable phytotoxicity by plant growth retardants tested was observed.

• Research in Plant Disease
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• v.17 no.3
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• pp.265-271
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• 2011

Seven phytoplasma diseases have been occurred on floricultural crops in Korea : Ph-ch1 and Ph-ch2 of chrysanthemum, Ph-lily of lily, petunia flat stem-Korean (PFS-K) of petunia, poinsettia branch inducing- Korean (PoiBI-K) of poinsettia, statis witches' broom-Korean (SWB-K) of statis and azalea witches broom (AWB). Classification of the seven phytoplasmal diseases based on 16S ribosomal RNA (rRNA) sequences showed that floricultural crop phytoplasma disease were widespread in order of aster yellow (AY), stolbur and X-disease in Korea. In phenotypic characters, the fasciation was occurred in both monocotyledon plant of lily and dicotyledon plants of petunia and poinsettia. Besides, the fascination was occurred in Ph-lily of stolbur, petunia PFS-K of AY and PoiBI-K of X-disease. This result indicated that phytoplasma classification based on 16S rRNA and symptoms are not consistently related. The comparison of 16S rRNA sequence of the seven floricultural crop phytoplasma with five tree phytoplasmal diseases of jujube witches' broom, paulownia witches' broom, wild jujube witches' broom, mulberry dwarf, golden rain phytoplasma occurred in Korea showed as high as 88.5-99.9% homology. Among them, especially mulberry dwarf showed the highest homology with the seven floricultural crop phytoplasms. Based on this result, floricultural crop phytoplasmas were assumed to be transmitted by insect vectors from tree phytoplasmas in Korea.

• Korean Journal of Breeding Science
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• v.42 no.6
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• pp.611-614
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• 2010

A new poinsettia cultivar 'Heidi' was bred by the National Institute of Horticultural and Herbal Science (NIHHS) in 2004. A cross was made between 'Freedom Rose', a variety with vigorously growing deep pink color, and 'Red Velvet', a variety with dark green leaves and red bracts in 2001. 'Heidi' was finally selected in 2004 after the investigation of the growth and flower characteristics from 2002 to 2004. It has velvety red colored elliptic bracts and transitional leaves, and medium intensity of rugosity between bract veins. Leaf blade is dark green, ovate shape and lobes are shallow. Petiole length is relatively short and stem color is reddish. 'Heidi' has free-branching ability and plant height is short. The bracts and transitional leaves are fully colored 7.5 weeks after short day commencement.

• Applied Microscopy
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• v.36 no.3
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• pp.195-208
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• 2006

Using light and scanning electron microscopy morphological studies of pollens were conducted to determine the sectional boundary and the relationships among eight species of section Zygophyllidium and its five related species of subg. Poinsettia. Pollen characters of 13 species were described, and their diagnostic keys were presented here. Based on the sculpturing patterns and the results of numerical analysis using 10 pollen characters 13 species were divided into four Pollen types: type I, having micro-reticulate shaped pollen (E. hexagona, E. lagunensis, E. hexagonoides and E. bilobata), type II, having reticulate shaped pollen (E. delicatula, E. extipulata, E. dentata, E. heterophylla, E. pulcherrima and E. cyathophora), type III, micro-reticulate shaped pollen with platten muri (E. lacera), and type IV, haying foveolate shaped pollen grains (E. chersonesa and E. eriantha). The results of pollen morphological studies suggest that the sect. Zygophyllidium should be delimited based on only four species, E. hexagona, E. lagunensis, E. hexagonoides and E. bilobata, E. delicatural and E. exstipulata of sect. Zygophyllidium must be transferred to subg. Poinsettia based on pollen morphology. E. eriantha and E. chersonesa having forveolate sculpturing pattern of pollen grains seem to be closely related with species from subg. Agaloma, and additional studies of these species are needed to determine the species relationships within Agaloma group.

• Korean Journal of Plant Taxonomy
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• v.38 no.4
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• pp.389-403
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• 2008

Seed morphological studies of 12 species of sect. Zygophyllidium and related Poinsettia using light and scanning electron microscopy were conducted to test the hypotheses of the sectional boundaries and species relationships. Characteristics of seeds, and the keys of identification of 12 species were presented. Seeds of 12 species were divided into 6 types based on the UPGMA tree from numerical analyses using nine seed characters. Type I, including E. uniglandulosa, is characterized by the foveolate seed with granulate testa cells. Type II, including species E. exstipulata, E. lagunensis, E. bilobata, E. hexagonoides and E. chersonesa, was recognized by the presence of inter-cellular granules among testa cells. Type III, including E. cyathophora, has a seed with acute apex, and concentric circles on the surface of testa cells. Type IV, including species of E. dentata and E. pentadactyla, has a seed with caruncle and lacking inter-cellular granules among testa cells. Type V, including E. hexagona, was characterized by the ovate seeds and lacking inter-cellular granules. Type VI, including E. eriantha and E. lacera, was recognized by the seeds with rectangular shape with caruncle. Based on the seed morphology, sect. Zygophyllidium should be defined only species with E. exstipulata, E. lagunensis, E. bilobata, E. hexagonoides and E. chersonesa. E. hexagona, traditionally included in this section, was closely related to E. dentata from Poinsettia.

• Proceedings of the Plant Resources Society of Korea Conference
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• v.18 no.1
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• pp.106-107
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• 2005

• Journal of Bio-Environment Control
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• v.13 no.2
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• pp.107-111
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• 2004

This study was conducted to examine the possibility of producing poinsettia with various growing media containing used perlite and rockwool slabs as medium components. Pot plants of Euphorbia pulcherrima 'Freedom Red' were grown in 10 media containing used perlite and particles of rockwool slabs at various ratios including 1:1 and 1:3 (v/v). Medium containing used perlite and peatmoss at 1:3 (v/v) was employed as the control treatment. Height, root length, length of the longest branch, number of roots, leaf area, and width and length of the largest bract of plants grown in media containing used perlite were significantly greater than those in the control. Stem diameter and bract count were not affected by the medium composition. From the results, used perlite and rockwool slabs were proved to be a practically useful materials as medium components for pot production of poinsettia plants.

• 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 Breeding Science
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• v.41 no.1
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• pp.32-35
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• 2009

A new poinsettia cultivar "Early bird" was bred by the National Institute of Horticultural and Herbal Science (NIHHS) in 2007. A cross was made between 'Ichiban', a variety with deep lobed transitional leaves and bright red bracts, and 'Freedom Red', a vigorously growing dark red colored variety in 2004. "Early bird" was finally selected in 2007 after the investigation of the growth and flower characteristics from 2005 to 2007. "Early bird" has bright red colored, wide obovate bracts. Leafblade is dark green and ovate. Plant height is short and stem color is greenish. Response to short day is early and its bracts and transitional leaves are fully colored 6.5 weeks after short day commencement.