• Korean Journal of Organic Agriculture
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• v.24 no.4
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• pp.849-857
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• 2016

In the growth of the Rubus coreanus Miquel fruits, the unripened (10 days) and ripened (25 days) fruits after flowering were harvested. The chemical characteristics of different maturational stages of the unripened and ripened fruits were investigated. Total amount of phenolic compounds was 4.00-7.56% in the unripened fruits and 3.78-5.57% in the ripened fruits, respectively. Furthermore, total amounts of organic acids such as malic, citric, succinic, and oxalic acids were 16.40 mg/100 g in the unripened fruits and 28.82 mg/100 g in the ripened fruits, respectively. In organic acids of the unripened and the ripened fruits, citric acid (8.76-15.47 mg/100 g) was the highest amount among other organic acids. Soluble sugars were significantly increased from 11.07 to 21.54% in the unripened and ripened fruits. Therefore, ripened fruits had the high levels of phenolic compounds, organic acids and soluble sugars. For the biological studies of R. coreanus, methanol extracts of R. coreanus leaves, fruits, and stems were evaluated for their insecticidal activities against Myzus persicae (Hemiptera: Aphididae), Plutella xylostella (Lepioptera: Plutellidae) and Spodoptera litura (Lepioptera: Noctuidae) by leaf dipping method. From these results, the extract of R. coreanus leaves revealed potent insecticidal activity against P. xylostella. However, the methanol extracts of R. coreanus fruits and stems had no any insecticidal activity against M. persicae, P. xylostella and S. litura. The R. coreanus leaves have promising potential as new insecticidal agent against P. xylostella.

• Journal of Bio-Environment Control
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• v.11 no.4
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• pp.193-198
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• 2002

Growth and tuber development of ‘Black Magic’calla lily as affected by the rain shelter with 50％ shading and the tuber size were investigated. Tubers of five grades in size were cultivated in the rain shelter or in the open field (control). Days to emergence of shoots in the rain shelter was accelerated by 4.2 days as compared to the open field. Emergence ratio was higher as the tuber was larger, tubers grown in the rain shelter showed the significance in the growth characteristics as compared to the control. There were no significant differences in the number of flowers per tuber between the rain shelter and the open field. Flower quality was 12.2 cm longer than that in the open field. flowering characteristics was improved with the increasing tuber size. Low infection of soft rot disease of 3∼22％ was found in the rain shelter as compared to the that of 19∼83％ in the open field. Thus tubers produced under the rain shelter showed improved quality, Even if the small tubers with diameters of 0.5∼1.0 cm were cultivated in the rain shelter, the weight and diameters of tuber harvested after approximately 7 months were 50.2 g and 5.7 cm, respectively.

• Journal of Bio-Environment Control
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• v.12 no.1
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• pp.1-6
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• 2003

This study was conducted under the condition of greenhouse to investigate the relationships between the period of long day (LD) treatment before short day treatment, the dry matter production and flower quality of cut chrysanthemum (Indicum group) cv. Reagan Improved at Wagenigen University in the Netherlands. Rooted cuttings of chrysanthemum (Indicum group) cv. Reagan Improved were transplanted on 6th, 13th, loth of September and all of them were treated with short-days (SD) on 21th September. The periods from planting until final harvest were 70, 77, 84 days after being planted for 1, 2, and 3 week-LD period, respectively. The time of flower initiation was similar in all treatments. The number of flowers per plant was greater in the plot of 3 week-LD period than that in the plot of 1 or 2 week-LD period. The fresh weight and dry weight of flowers also increased more in the plot of 3 week-LD period than that in the 1 week-LD period by 4g and 0.4g, respectively. The final dry matter production ($g{\cdot}m$^{-2}$ ) was greater in the treatment of 3 week-LD period than 1 or 2week-LD period. In this study, LD period before short day treatment did not affect the time of flower initiation and flower quality. As a result, 3 week-LD period before short day treatment was strongly recommanded for producing high quality cut flowers of greenhouse-grown chrysanthemum.

• Korean Journal of Medicinal Crop Science
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• v.27 no.4
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• pp.271-277
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• 2019

Background: Rehmannia glutinosa (Gaertn.) Libosch. ex Steud. has long been used as a traditional medicinal plant in Korea. This study was carried out to investigate the emergence conditions during the seedling periods in R. glutinosa. Methods and Results: The rhizomes of R. glutinosa variety (Jihwang 1) were harvested in the 22, March, 2018. The rhizomes were sown on in 50-cell plug trays. The emergence rates of seedlings at $15^{\circ}C$, $20^{\circ}C$, $25-40^{\circ}C$, and $45^{\circ}C$ treatment seedling were 1.3%, 96%, 100% and 0%, respectively. Rhizome rot was occurred at the temperature of $15^{\circ}C$ and $45^{\circ}C$. The emergence rates of seedlings in high moisture (HM), moderate moisture (MM) and low moisture (LM) treatments at $35^{\circ}C$ were 99.3%, 100%, and 0%, respectively. Drought damage was recorded in plant with the LM treatment. Seedling quality surveys were carried out at 10-days intervals from 10 to 60 days after sowing (DAS). Leaf length and leaf width were increasing until 50 DAS and the number of leaves was increasing until 60 DAS. Root length was increasing until 40 DAS, and then, flowering occurred from 30 to 60 DAS. Lastly, at 40 DAS, leaf aging and root enlargement was observed. Conclusions: We concluded that the emergence of seedlings was possible in the range of 20 to $40^{\circ}C$. Considering drying and rotting damage, we concluded that the moderate level of moisture is most appropriate for seedling emergence. In addition, we concluded that optimal seedling periods are between 30 and 40 DAS.

• 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.

• Korean Journal of Weed Science
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• v.8 no.3
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• pp.309-316
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• 1988

Several experiments were conducted to investigate the achene viability and growth characteristics of Eclipta prostrata (L.) L. No dormancy and no after-ripening requirement were found for E. prostrata achenes. When achenes were stored at room temperature, germination did not decrease with up to 5 months storage. Large differences in loss of viability of E. prostrata achenes occurred when different dehydration methods were used. Immediate dehydration resulted in high viability, but slow dehydration resulted in severe loss of viability. Achene viability at shallow burial depths (5 and 10 cm deep) was lower under upland soil conditions than under lowland soil conditions. Seedling growth was greatly reduced when flooding to a depth of 10 cm occurred at or before the 4-leaf stage. Flooding after the 4-leaf stage stimulated stem elongation. Branching started from the second week and usually terminated at the tenth week. Leaf size was determined by the branch which are related to the assimilate supply. Flowering of E. prostrata started during the fifth week after emergence, and mature achenes were produced from the sixth week. Ten to 14 days were needed for the achenes to mature. About 14,000 achenes were produced on each plant. Achene production per week increased from the sixth week to the tenth week and thereafter it declined. The average number of achenes per inflorescence decreased with delay in flowering.

• Journal of Plant Biotechnology
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• v.39 no.3
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• pp.140-145
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• 2012

The flowering locus T (FT) gene, of which expression will be controlled at high temperature by heat shock promoter (it printed as to HSproFT), was introduced into spray-type chrysanthemum (Dendranthema grandiflorum (Ramat.) Kitamura) 2 cultivars ('Pink PangPang' and 'Pink Pride' by co-cultivation with Agrobacterium tumefaciens strain C58C1 harboring pCAMBIA2300 containing the HSproFT gene. After leaf segments of the 2 cultivars were infected with the A. tumafaciens with C58C1 as explants, shoots were regenerated from the explants cultured on the $1^{st}$ selection medium (MS basal salts + 1.0 mg/L BA, 0.5 mg/L IAA + 10 mg/L kanamycin + 0.7% plant agar, pH 5.8). The shoots were transferred into the $2^{nd}$ selection medium (MS basal salts + 1.0 mg/L BA, 0.5 mg/L IAA + 20 mg/L kanamycin + 0.7% plant agar, pH 5.8). One hundred seventeen plantlets from 'Pink PangPang' and 5 ones from 'Pink Pride' were confirmed as transformants by PCR analysis. Twenty six of the transformants and non-transformants were acclimatized and established well in a green house. Eights of 26 transgenic lines showed flower bud 1.7~10 days earlier than nontransgenic plants, and 24 of them flowered 1~6 days earlier than non- transgenic plants. The shape and color of flower of all HSproFT-transgenic lines were not different with those of non- transgenic plants.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.14
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• pp.1-40
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• 1973

There is a general tendency to increase nitrogen level in rice production to insure an increased yield. On the other hand, percentage of ripened grains is getting decreased with such an increased fertilizer level. Decreasing of the percentage is one of the important yield limiting factors. Especially the newly developed rice variety, 'Tongil' is characterized by a relatively low percentage of ripened grains as compared with the other leading varieties. Therefore, these studies were aimed to finding out of some measures for the improvement of ripening in rice. The studies had been carried out in the field and in the phytotron during the period of three years from 1970 to 1972 at the Crop Experiment Station in Suwon. The results obtained from the experiments could be summarized as follows: 1. The spikelet of Tongil was longer in length, more narrow in width, thinner in thickness, smaller in the volume of grains and lighter in grain weight than those of Jinheung. The specific gravity of grain was closely correlated with grain weight and the relationship with thickness, width and length was getting smaller in Jinheung. On the other hand, Tongil showed a different pattern from Jinheung. The relationship of the specific gravity with grain weight was the greatest and followed by that with the width, thickness and length, in order. 2. The distribution of grain weight selected by specific gravity was different from one variety to another. Most of grains of Jinheung were distributed over the specific gravity of 1.12 with its peak at 1.18, but many of grains of Tongil were distributed below 1.12 with its peak at 1.16. The brown/rough rice ratio was sharply declined below the specific gravity of 1.06 in Jinheung, but that of Tongil was not declined from the 1.20 to the 0.96. Accordingly, it seemed to be unfair to make the specific gravity criterion for ripened grains at 1.06 in the Tongil variety. 3. The increasing tendency of grain weight after flowering was different depending on varieties. Generally speaking, rice varieties originated from cold area showed a slow grain weight increase while Tongil was rapid except at lower temperature in late ripening stage. 4. In the late-tillered culms or weak culms, the number of spikelets was small and the percentage of ripened grains was low. Tongil produced more late-tillered culms and had a longer flowering duration especially at lower temperature, resulting in a lower percentage of ripened grains. 5. The leaf blade of Tongil was short, broad and errect, having light receiving status for photosynthesis was better. The photosynthetic activity of Tongil per unit leaf area was higher than that of Jinheung at higher temperature, but lower at lower temperature. 6. Tongil was highly resistant to lodging because of short culm length, and thick lower-internodes. Before flowering, Tongil had a relatively higher amount of sugars, phosphate, silicate, calcium, manganese and magnesium. 7. The number of spikelets of Tongil was much more than that of Jinheung. The negative correlation was observed between the number of spikelets and percentage of ripened grains in Jinheung, but no correlation was found in Tongil grown at higher temperature. Therefore, grain yield was increased with increased number of spikelets in Tongil. Anthesis was not occurred below 21$^{\circ}C$ in Tongil, so sterile spikelets were increased at lower temperature during flowering stage. 8. The root distribution of Jinheung was deeper than that of Tongil. The root activity of Tongil evaluated by $\alpha$-naphthylamine oxidation method, was higher than that of Jinheung at higher temperature, but lower at lower temperature. It is seemed to be related with discoloration of leaf blades. 9. Tongil had a better light receiving status for photosynthesis and a better productive structure with balance between photosynthesis and respiration, so it is seemed that tongil has more ideal plant type for getting of a higher grain yield as compared with Jinheung. 10. Solar radiation during the 10 days before to 30 days after flowering seemed enough for ripening in suwon, but the air temperature dropped down below 22$^{\circ}C$ beyond August 25. Therefore, it was believed that air temperature is one of ripening limiting factors in this case. 11. The optimum temperature for ripening in Jinheung was relatively lower than that of Tongil requriing more than $25^{\circ}C$. Air temperature below 21$^{\circ}C$ was one of limiting factors for ripening in Tongil. 12. It seemed that Jinheung has relatively high photosensitivity and moderate thermosensitivity, while Tongil has a low photosensitivity, high thermosensitivity and longer basic vegetative phase. 13. Under a condition of higher nitrogen application at late growing stage, the grain yield of Jinheung was increased with improvement of percentage of ripened grains, while grain yield of Tongil decreased due to decreasing the number of spikelets although photosynthetic activity after flowering was. increased. 14. The grain yield of Jinheung was decreased slightly in the late transplanting culture since its photosynthetic activity was relatively high at lower temperature, but that of Tonil was decreased due to its inactive photosynthetic activity at lower temperature. The highest yield of Tongil was obtained in the early transplanting culture. 15. Tongil was adapted to a higher fertilizer and dense transplanting, and the percentage of ripened grains was improved by shortening of the flowering duration with increased number of seedlings per hill. 16. The percentage of vigorous tillers was increased with a denser transplanting and increasing in number of seedlings per hill. 17. The possibility to improve percentage of ripened grains was shown with phosphate application at lower temperature. The above mentioned results are again summarized below. The Japonica type leading varieties should be flowered before August 20 to insure a satisfactory ripening of grains. Nitrogen applied should not be more than 7.5kg/10a as the basal-dressing and the remained nitrogen should be applied at the later growing stage to increase their photosynthetic activity. The morphological and physiological characteristics of Tongil, a semi-dwarf, Indica $\times$ Japonica hybrid variety, are very different from those of other leading rice varieties, requring changes in seed selection by specific gravity method, in milling and in the cultural practices. Considering the peculiar distribution of grains selected by the method and the brown/rough rice ratio, the specific gravity criterion for seed selection should be changed from the currently employed 1.06 to about 0.96 for Tongil. In milling process, it would be advisable to bear in mind the specific traits of Tongil grain appearance. Tongil is a variety with many weak tillers and under lower temperature condition flowering is delayed. Such characteristics result in inactivation of roots and leaf blades which affects substantially lowering of the percentage of ripened grains due to increased unfertilized spikelets. In addition, Tongil is adapted well to higher nitrogen application. Therefore, it would be recommended to transplant Tongil variety earlier in season under the condition of higer nitrogen, phosphate and silicate. A dense planting-space with three vigorous seedlings per hill should be practiced in this case. In order to manifest fully the capability of Tongil, several aspects such as the varietal improvement, culural practices and milling process should be more intensively considered in the future.he future.

• The Korean Journal of Pesticide Science
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• v.17 no.4
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• pp.440-447
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• 2013

F. occidentalis (WFT, western flower thrips) is a major pest in artificial chrysanthemum houses. Nnumber of WFT attracted to yellow sticky trap was highest at trap plant and lowest at 15 and 20m places away from trap plant. Number of WFT attracted to yellow stick trap when trap plant was placed in chrysanthemum house 30 days after planting (resident WFT) was 4.4~7.7 times more than at 5 and 10 m places away from trap plant and when trap plant was placed in chrysanthemum house immediately after planting (resident WFT) was 5.7~9.4 times more at 5 and 10 m places away from trap plant. Number of WFT between the place trap plant located and unlocated was undifferent when cultured chrysanthemum formed flower. In case of the plot that trap plant and natural enemy was used simultaneously, number of WFT was highter then chemicals plot. In case of the plot that trap plant and chamicals (chemicals was sprayed on trap plant only) WFT was controlled in trap plant place only but density of WFT on 5m and 10m places away from trap plant was increased. Therefore, WFT could be controlled effectively by use of trap plant (flowering yellow chrysanthemum) and natural enemy simultaneously.

• Korean Journal of Weed Science
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• v.6 no.1
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• pp.1-6
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• 1986

The growth, development, and morphological characteristics of Echinochtoa colons (L.) Link were determined through one life cycle. E. colons emerged 2 to 3 days after seeding (DAS) and reached the two leaf stage by 8 DAS. During the early growth stages, root length was greater than plant height, but the relationship was reversed from 4 weeks after seeding (WAS). Tillering started from the third leaf of the main culm as the sixth leaf on the main calm emerged. The unfolding of the leaves and tillering followed a regular pattern during the vegetative growth period. This resulted in the production of 19 tillers (5 primary, 12 secondary, 1 tertiary, and I nodal) at the 14-leaf stage. Shoot-root weight ratio was highest just before panicle initiation. The second spike from the top of the panicle was the shortest and produced the fewest seeds. Thereafter, spike length and the number of seeds per spike generally increased, the lower the position of the spike on the panicle. Seeds on the lower spikes weighed less and had lower germination ability than those from the upper spikes. Adventitious roots arose from the leaf sheath bases of a flowering stalk. The ability to produce adventitious roots was greater in a younger stalls than in an older stalk.