• Korean Journal of Medicinal Crop Science
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• v.13 no.4
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• pp.186-189
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• 2005

Plant flowering should be mainly affected by temperature and daylength. The study was carried out to measure the effect of temperature during winter on growth and floret flowering of Orostachys japonicus grown under 2 hour night break. Temperature was controlled above $10^{\circ}C$ and $20^{\circ}C$ as heating boilers were run below them to compare the natural temperature. Night-break treatment was done on August 25 and afterward samples were taken every 4 weeks to check growth, morphological and flowering related characters. Plant height, inflorescence length, number of leaves including bracts and stem diameter were increased in heating temperatures of > $10^{\circ}C$ compared to natural temperature although similar in the two heating ones. Leaves and bracts, florets, stem, root, shoot and total dry weights showed the same response as the above morphological and flowering related characters. Florets were more formed but less flowered with higher temperatures. Anthesis rates of individual plant were 100% in natural temperature, 25% in > $10^{\circ}C$ heating temperature but none in > $20^{\circ}C$ heating temperature.

• Korean journal of applied entomology
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• v.52 no.1
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• pp.23-27
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• 2013

Investigations were conducted to prevent entrance of Bemisia tabaci (Gennadius) with very fine mesh nets. B. tabaci vectors tomato yellow leaf curl virus in tomatoes. B. tabaci could be completely prevented to penetrate into an 83 mesh net, though few of them passed the 60 mesh net. An independent 60 mesh net cage was built within one of the three interconnected common plastic greenhouse ($21.0{\times}18.3m$) in order to find its usefulness as a crop protection tool from insect pests. TYLCV infected tomato plants were not detected, though a few eggs of B. tabaci and mines of Liriomyza trifolii (Burgess) were detected locally at the entrance of the sliding door. There were practically no significant differences between treatments of nets and the conventional plant height, leaf length and width, number of floret clusters, sugar brix, and product yield. In viewpoints of commercialization, it could be considered highly prospectful to apply to the nets to glasshouses or other greenhouses in which the growing period of crops is long, if the nets were used in the openings of sides, ceilings, and entrances of the greenhouse. However, it might be necessary to take preventive measures for occurrences of insect pests living in soil, temporarily or permanently, as well as high humidity diseases.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.31 no.1
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• pp.97-103
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• 1986

In order to investigate the important morphological traits, and grain yield and its components on basis of regional variation of barley plant, Olbori was tested at 3 locations Suwon, Daejeon and Jinju for 3 years. It needed seven days around 15$^{\circ}C$ of daily average temperature for seed emergence. 104 to 144 days for Daejeon and 135 to 142 for Jinju after sowing are needed for productive tillers according to the different sowing dates, and % of productive tillers were ranged on 37-77%, showing higher value at the southern region. Young spike elongated slowly at early stage, and after floret differentiation it appeared rapid development with 1.05-1.95 mm elongating per day. Analysis of variance indicated that only number of kernels/spike showed significant differences among locations, but every traits related to grain yields revealed the significant differences among different sowing dates. Little differences between locations existed on grain yield but its large variation appeared between sowing dates, especially indicating more variation at northern regions.

• Horticultural Science & Technology
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• v.32 no.6
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• pp.794-802
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• 2014

The aim of this study was to determine the effect of day-length extension treatment using LED lighting (blue, green, red, or 3 mixed) on vegetative growth and flowering of freesia 'Yvonne', in comparison to that using glow lamps and metal halide lamps. Lighting treatments were imposed from 5 PM to 8 PM for 150 days from after flower bud differentiation to flowering end. For the period from leaf emergence to floral bud formation, no light source affected plant height but the number of leaves was decreased by the metal halide lamp. The highest SPAD value in the flower bud developing period occurred in the metal halide lamp treatment. The time of flowering was advanced by blue or green LED treatment compared to the no lighting control. The green LED lighting advanced flowering by 6 and 8 days compared to no lighting and metal halide lamp treatment, respectively. The blooming period tended to be shortened by the red LED treatment. As for the flower characteristics of 'Yvonne', floret length and width, and the weight of cut flowers were highest in the metal halide lamp treatment. Red LED decreased corm width and weight of 'Yvonne' while glow lamp decreased height and weight. Starch contents in corm were not influenced by the lighting source. Our results indicate that the green LED lighting advanced the time of flowering and the metal halide lamp was good for cut-flower quality.

• 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.34 no.6
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• pp.966-976
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• 2016

A new bright yellow gerbera (Gerbera hybrida Hort.) cultivar, 'Joyful', was released by the Flower Research Institute of Gyeongsangnam-do Agricultural Research & Extension Service in 2013. 'Joyful' was developed in Changwon from 2005 to 2006 and is a cross between 'Chowoo', a semi-double type gerbera cultivar with yellow-orange colored flowers, and 'Focus', a semi-double type cultivar with yellow colored flowers. The characteristics trials for selection were conducted from 2007 to 2009. 'Joyful' has large, semi-double type flowers with yellow (RHS, 12-A) ray florets and a brown central part. It also has a stable flower shape, strong peduncles, and a vase life of 12.8 days. The average flower yield of 'Joyful' was determined in greenhouse trials carried out from 2008 to 2010 and is 49.2 stems per plant per year. 'Joyful' was demonstrated to be a new cultivar based on ploidy tests and RAPD analysis and was registered (Grant No. 4574) to the Korea Seed and Variety Service (KSVS) for commercialization in 2013.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.5
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• pp.600-607
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• 1995

Orostachys japonicus, called Wasong and used as anti-tumor medicinal plant, was cultivated in plastic house. The experiment was done to clarify the effect of long-day and night-break treatment at the timing of bolting on its morphological characters, organ dry weight and flowering of florets. After grown in 15cm plastic boxes containing 2:1 soil:peat moss mixture for about 4 months, long-day of 16 hours and night-break of 2 hours around midnight were treated from Sept. 9. The plants were sampled 5 times at 2-week interval after the treatments. Long-day and night-break treatment delayed the growth of inflorescence and showed greater stem diameter on the last sampling and no. of leaves and bracts than the natural daylength. The treatments also had greater leaf and bract dry weight since 2 weeks, and the other fraction and total dry weights since 4 weeks but less floret dry weight from 4 to 6 weeks after the treatments than the natural daylength. The treatments, however, decreased no. of flowered florets and ratio of flowering plants although all the treatments showed nearly the same no. of total florets per plant until 6 weeks after the treatments, late October, which resulted in the modification of source to sink or vice versa. In the natural daylength, the florets were functioned as sink, while root, leaf and bract as source, but in the long-day and night-break treatments stem and florets were done as sink.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.5
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• pp.503-514
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• 1997

The morphogenesis of panicle and spikelet in paddy rice has been studied in high yielding Indica$\times$Japonica hybrid cultivar, Milyang 23 and a Japonica type cultivar, Koshihikari. Germinated seeds planted in $5000^{-1}$ a pots filled with submerged soil and cultured under natural conditions. The young panicle of main stem were continuously dissected and observered by Cryo-SEM from the panicle initiation stage until heading stage. Although the date of panicle differentiation and heading in Koshihikari earlier than those of Milyang 23. the sequence of panicle development in two cultivars begins when first bract primordium at opposite side of flag-leaf primordium differentiated, synchronously followed by growth of the primary branch primordia (PBPs) and secondary branch primordia (SBPs), spikelet primordia(SPs), glumes as lateral organs on rachilla and organs composing single floret, and successive sporogenesis in the young spikelets continue after the enclosure by lemma and palea. The PBPs are acropetally initiated from the base of the panicle primordium, and the SBPs alternately differentiate from the base of upper PBP which differentiate later than the lower PBP. Spikelet development starts at the top of upper side PBP of the young panicle and continue basipetally even though SBPs continue to develop at the lower primary branch. Each PBP, SBP and SP differentiate with differentiation bract or bract hair cell around the base of each their primordia. The observation could confirm that Milyang 23 has not only 2~3 more defferentiated PBPs, but also more SBPs and SPs especially from middle-lower primary branch, at end of their differentiation stages, as compared to those of Koshihikari.

• Korean Journal of Plant Taxonomy
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• v.38 no.4
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• pp.477-502
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• 2008

Morphological characters of inflorescence, spikelet, rachilla, glume, lemma and palea about 17 taxa of Korean Poa L. were investigated to evaluate their taxonomic significances. The bulbil present or not, inflorescence shape, callus shape of lemma and surface shape of palea were thought to be the subgenus characters. The keels shapes of palea, the number of lower glume, lateral nerve shape of lemma were thought to be the section characters. The number of floret, rachilla present or not, the number of lower glume, nerve shape of glume, surface shape of lemma were thought to be the species characters. Consequently, 17 taxa of the Korean Poa L. is classified into 3 subgenus (Ochlopoa, Stenopoa, Stenopoa), 7 section(Arenariae, Ochlopoa, Homalopoa, Poa, Pandemos, Tichopoa, Stenopoa). 6 taxa, P. ullungdoensis, P. takeshimana and P. matsumurae, P. nipponica, P. radula, P. viridula, not included in the existing classification system, were suggested to their taxonomic category in infragenic rank, and P. nemoralis, had been included in section Stenopoa of subgenus Stenopoa, was proposed to move to section Poa of subgenus Poa. P. ullungdoensis, reported as new species in 1955, was grasped its taxonomic identity.

• Korean Journal of Medicinal Crop Science
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• v.15 no.6
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• pp.429-433
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• 2007

Shoot weight of Orostachys japonicus should determine its profitability. The study was carried out to measure the effect of nitrogen (N) fertilization level (0, 5, 10, 20kg/10a) on its growth, morphological characters, and flowering. Night-break treatment of 2 hours at midnight were done since Aug. 25 when afterward samples were taken every 4 weeks to Nov. 16. Growth, morphological and flowering related characters were measured from each sample. Plant height, inflorescence length, number of leaves including bracts and stem diameter were decreased with increased N levels. Leaf and bract, floret, shoot and total dry weights as well as withering rate showed similar response to the above morphological characters. Florets were less formed with increased N levels but were not flowered due to the night-break treatment, meaning that N fertilization had little effect on its growth and anthesis of the florets.