• The Plant Pathology Journal
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• v.21 no.4
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• pp.377-382
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• 2005

Infection rate of Chrysanthemum stunt viroid (CSVd) in 64 commercial chrysanthemum cultivars cultivated in Korea ranged from 9.7 to 66.8$\%$. Symptoms on leaves of CSVd-infected chrysanthemum included yellow spots, chlorosis, vein clearing, vein bending and crumpling. CSVd induced flower malformation in 'Scot', color change in 'Sharotte', and color breaking in 'Sharon'. CSVd caused reduction of plant height, leaf size, flower size and the flowers number by $32-50\%,\;26-35\%$, $14-36\%\;and\;14-75\%$, respectively. In conclusion, CSVd affected plant height, leaf size and flower quality in chrysanthemum plants.

• Horticultural Science & Technology
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• v.16 no.4
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• pp.531-532
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• 1998

This study was conducted to investigate the optimum concentration and time of BA treatments for the improvement of flowering in Cymbidium encifolium 'Tekkotsusosin'. The flowering rate was increased by the higher concentration of BA treatment, and reached 100% by $400mg{\cdot}L^{-1}$ treatment. But high concentration induced the flower malformation. Therefore, the optimum concentration of BA for increased of flowering rate was about $300mg{\cdot}L^{-1}$. In the time of BA treatment, plants which were treated in June to August by BA $300mg{\cdot}L^{-1}$ were flowered, especially up to 100% in August. However, those treated in April, May, and September did not.

• Horticultural Science & Technology
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• v.17 no.6
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• pp.755-757
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• 1999

This study was conducted to investigate the optimum temperature after BA treatments for the indution of flowering in Cymbidium ensifolium 'Tekkotsusosin'. Flowering rate was 90% at $30/25^{\circ}C$ (day/night), 50% at $25/20^{\circ}C$ and the natural condition as control, and non flowering at $20/15^{\circ}C$. Malformation rate of flower shape was at $25/20^{\circ}C$, 4% at $30/25^{\circ}C$, and 9% in the natural condition. The length and number of flowering stalks per plant were most at $30/25^{\circ}C$ treatment. After BA spraying, the lowest air temperature for flowering was assumed to be about $20^{\circ}C$.

• The Plant Pathology Journal
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• v.24 no.3
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• pp.279-282
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• 2008

This study describes a phytoplasmal disease occurring in Petunia leaves grown in the glasshouse of the National Horticultural Research Institute, Suwon, Korea. Abnormal growth like flattened stem with flower malformation or phyllody was observed from the plant. The DNA extracted from the diseased leaves was amplified using a universal primer pair of P1/P6 derived from the conserved 16S rRNA gene of Mollicutes giving the expected polymerase chain reaction(PCR) product of 1.5 kb. In the nested PCR assays, the expected DNA fragment of 1.1 kb was amplified with the specific primer pair R16F1/R16R1 that was designed on the basis of aster yellows(AY) phytoplasma 16S rDNA sequences. The 1.1 kb PCR products were cloned and nucleotide sequences were determined, and the sequences of the cloned 168 rRNA gene were deposited in the GenBank database under the accession no. of EU267779. Analysis of the homology percent of the 168 rDNA of PFS-K showed the closest relationship with Hydrangea phyllody phytoplasma(AY265215), Brassica napus phytoplasma(EU123466) and AY phytoplasma CHRY(AY180956). Phytoplasma isolated from the diseased Petunia was designated as Petunia flat stem phytoplasma Korean isolate(PFS-K) in this study. Flattened stem occurring in Petunia was confirmed as infection of AY group of phytoplasma by determination of 16S rRNA gene sequences of phytoplasma and microscopic observation of phytoplasma bodies. This is the first report on the phytoplasmal disease in Petunia in Korea.

• Korean Journal Plant Pathology
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• v.14 no.1
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• pp.83-91
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• 1998

Gladioli (Gladiolus hybridus) showing flower colour breaking leaf mosaics, notched leaf, and dwarfing or lack of visible symptoms were collected from gladioli growing areas in Taegu and Kyungpook province, Korea. The three viruses isolated from the naturally infected gladioli were identified as broad bean wilt virus (BBWV), cucumber mosaic virus (CMV), and tobacco rattle virus (TRV) by their host range, immunosorbent electron microscopy (ISEM), enzyme-linked immunosorbent assay (ELISA), direct tissue blotting immunoassay (DTBIA), and intracellural symptoms. By DTBIA and ISEM, TRV was detected in gladiolus showing notched leaf, while CMV was frequently detected in gladioli with dwarfing, color breaking and malformation of flowers. BBWV was also often detected in many symptomless gladiolus plants, but TRV was detected in notched-leaf of gladiolus. Electron microcopic examination of negatively stained preparations showed that BBWV and CMV are spherical particles of 28 nm and 30 nm in diameter, and TRV is rigid rod-shaped particles of 40∼200 nm in length. The rigid rodshaped virus particles reacted positively with TRV antiserum in ISEM and DTBIA, respectively.

• The Plant Pathology Journal
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• v.21 no.4
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• pp.383-386
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• 2005

In 2003 typical phytoplasma symptoms of witches' broom and flower malformation were observed on statice (Limonium sinuatum) plants grown at commercial greenhouses in Busan, South Korea. The DNA extracted from the infected leaves was amplified using universal primer pair of Pl/P6 derived from conserved 16S rRNA gene of Mollicutes giving the expected Polymerase chain reaction (PCR) product of 1.5 kb. In the nested PCR assays, the expected DNA fragment of 1.1 kb was amplified with the specific primer pair 16Fl/Rl that was designed on the basis of aster yellows (AY) phytoplasma 16S rDNA sequences. The 1.1 kb PCR products were cloned and nucleotide sequences were determined. The sequences were identical to that of Onion yellows OY phytoplasma (GenBank accession no. D12569) isolated from Onion in Japan. Electron microscopy of thin sections of leaf veins showed phytoplasma bodies in the phloem. Statice witches' broom symptom occurred on statice in commercial greenhouses in Korea was confirmed as infection of AY phytoplasma by transmission electron microscopy observation, and by determination of 16S rRNA gene sequences of phytoplasma.

• Horticultural Science & Technology
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• v.32 no.4
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• pp.571-575
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• 2014

'Dream Song' is a cultivar of Gypsophila paniculata developed by the Jeollabuk-do Agricultural Research & Extension Services in 2010 for cut-flower production. This hybrid was bred from 121 seedlings collected from an open-pollinated population of 'Gyp06-11'. It has novel morphological characteristics of upright plant type, lanceolate leaves, double florets with a few bright white-colored petals of obovate shape, truncate petal tips, and cup-shaped calyces. Furthermore 'Dream Song' has desirable cultivation characteristics including narrow branching angle, and moderate resistance to powdery mildew, thrips and leaf miners. Moreover it produces more primary branches, and longer internodes and flower stalks than reference cultivar 'Bristol Fairy' during summer cultivation in a subalpine area (500 m over the sea level). Flowering in 'Dream Song' is delayed by about 17 days as compared to 'Bristol Fairy'. 'Dream Song' produces normal flowers with 2 pistils and an average of 10.4 stamens, with fewer malformed flowers than 'Bristol Fairy'.

• Horticultural Science & Technology
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• v.31 no.6
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• pp.714-719
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• 2013

The bent peduncle phenomenon (BPP) is known as a kind of physiological disorders found in cut rose plants, which causes the reduction of cut flower yields. As yet unknown mechanisms, however, it has not been easy to find solutions for BPP. To address this challenge, this study was conducted to investigate the characteristics of floral morphology, growth, and endogenous phytohormone level of BPP shoots in cut rose plants (Rosa hybrida L. 'Beast'). Morphological observation confirmed the fact that BPP was accompanied by the early formation and being phyllody of a specific sepal among five sepals, which gave rise to peduncle bending in the upper part of the phyllody with fasciation. Year-round BPP frequency in 'Beast' cultivar was in the range of 5 to 20% with seasonal change, increasing rapidly with an average temperature rise in summer. Except bent peduncle, the BPP shoots appeared to grow normally in terms of speed and size of floral development in comparison with normal. However, carbohydrate distribution to the floral part in BPP shoots was significantly reduced. The level of endogenous IAA (3-Indoleacetic acid) within the floral part in BPP shoots was highly maintained during floral development, in contrast to normal shoots. $GA_3$ contents were not significantly different between normal and BPP shoots. This study indicates that BPP would be induced by a series of courses: abnormally early formation of a specific sepal relative to high temperature, being phyllody of the sepal with fasciation, and continuous supply of endogenous IAA by phyllody.