• Journal of Power System Engineering
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• v.21 no.5
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• pp.20-28
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• 2017

The steady-state, incompressible and three-dimensional numerical analysis was performed to investigate the flow fields around the seabed tiller used for soil improvement in coastal fisheries and the pulling force and buoyancy generated by tiller operation. The turbulence model used in this study is a realizable $k-{\varepsilon}$. As a results, at a stationary current or a current speed of 1.2 knots, where rotor rotates in a clockwise direction, a typical vortex pair appears near the tip of the rotor except for the edge, and the strength of the vortex pair increases with the number of revolutions of the rotor. The pulling force of the tiller rotating in the counterclockwise direction increases with the number of revolutions. Also, when the current flows at 1.2 knots and the rotor rotates clockwise, the pulling force of the tiller acts on the upstream side irrespective of the number of rotations of the rotor, so that no force is applied. The buoyancy of the tiller acts on the seawater surface if the flow direction inside the rotor is the same as the direction of rotation of the rotor, regardless of the current velocity, otherwise it acts on the seabed.

• Journal of The Korean Society of Grassland and Forage Science
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• v.11 no.1
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• pp.6-11
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• 1991

In order to classify the varieties by the characters to evaluating potential winter hardiness was examined using the relationships between autumn growth of seedling plants and the dry weight of plant(DW), and yield components of 1st cutting in 16 varieties of perennial ryegrass grown under individual plant basis.The results are summarized as tollows:1. The dry weight of plant(L)W) was positively correlated with the number of tillers of seedling plants, but negatively correlated with seedling vigors of plants in autumn growth. 2. The dry weight of plant(L)W) indicated positively significant correlations with the dry weight of heading tillers(HDW), number of tillers per plant(NT), number of vegetative tillers(VNT), number of heading tillers(HNT), dry weight of a tiller(WT) and heading rates(HR) of 1st cutting.3. Relative tiller appearance rates(RTAK) corresponded with the seasonal patterns of tillering ability. Thevariety with a low values of relative tiller appearance rates(RTAR) showed vigorous tillering ability inautumn growth, but the variety with a high values of relative tiller appearance rates(KTAR) showedvigorous tillering ability in spring growth.4. The dry weight of plant per relative tiller appearance rates(DW/RTAR) indicated positively significant correlations with the dry weight of plant(DU7, plant length(PL), dry weight of heading tillers(HDW), number of tillers per plant(NT), number of heading tillers(HNrr), dry weight of a tiller(WT) and heading rates(HR) of 1st cutting.5. The varieties were classified into 2 groups by the dry weight of plant per relative tiller appearance rates(DW/RTAR). Thus. Manhattan, P-2, Tonga, Tove, Hella. I'eramo and Fiesta belong to the group of DW/RTAII>l. 0, and Maprima, Caliente, Tempo, Gambit, Magella, Prana. Reveille, Barlet and Bravo belong to the group of DW/RTAR

• Journal of Biosystems Engineering
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• v.29 no.2
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• pp.109-120
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• 2004

To obtain basic information for precision agriculture, spatial variability of rice growth condition was evaluated in 100m ${\times}$100m paddy field. The rice growth condition of four hundred locations in the field were investigated to analyze the spatial variability of their properties ; SPAD, plant length and tiller number. Geostatistical analysis was carried out to examine within-field spatial variability using semivariograms and kriged maps as well as descriptive statistics. Descriptive statistics showed that the coefficient of variation for SPAD, plant length, and tiller number exceeded 5.70 %, suggesting a relatively high variability. Geostatistical analysis indicated a high spatial dependence for all the properties except for the second tiller number. The range of spatial dependence was about 20 m for SPAD, plant length, and tiller number. Based on the results of spatial dependence, kriged maps were prepared for the properties to analyse their spatial distribution in the field. The results reflected the history of field management. In conclusion, the need for site-specific field management and possibility of precision agriculture were demonstrated even in an almost flat paddy field.

• Journal of Life Science
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• v.7 no.1
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• pp.59-65
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• 1997

In this experiment, gene actions were analysized for seven barley parents in order to obtain basic information on their genetic improvement by diallel crosses. The results obtained were summarized as follows. In analysis of variance, additive, dominant, maternal and reciprocal effects were observed significantly for culm length, tiller number, number of spiked per plant, culm diameter, awn length, leaf width, number of grains per spike, and 1000 grain weight. Over-dominance was shown by Vr-Wr graphic analysis in five characters such as tiller number, number of spikes per plant, length of flag leaf, number of grains per spike, and 1000 grain weight, and partial dominance in four characters such as culm length, culm diameter, awn length, and leaf width. Component of genetic varience analyzed for four characters such as culm diameter, awn length, length of flag leaf, and leaf width showed that additive effects were higher than dominant effects. Culm length, tiller number, number of spikes per plant, number of grains per spike, and 1000 grain weight showed dominant effects higher than additive effects. The narrow-sense heritability for awn length, leaf width, and number of grains per spike showed high values as more than 0.62, while broad-sense heritability for culm length, number of spikes per plant, culm diameter, awn length, leaf width, number of grains per spike, and 1000 grain weight showed high values as more than 0.65.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.2
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• pp.141-148
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• 1992

Field experiment was carried out to investigate the effect of plant growth regulator (PGR); IAA, GA, Kinetin to regrowth of sorghum and pearlmillet according to variety and plant growth stage. Kinetin application after cut increased tiller number and decreased dry weight of regrowth, but its application on sorghum stubble in water stress increased tiller number and leaf elongation rate, consequently increased regrowth dry weight. GA application reduced tiller production in both species, but tiller formation in pearlmillet was decreased more than in sorghum by promoting leaf elongation of old tiller. Nonstructural carbohydrate (NSC) of stubble during regrowth was consumed less at anthesis than at stem elongation stage because of senescence of tiller primordia. GA treatment reduced NSC content more than other PGR in both plant species, by consuming reserve NSC and stimulating rapid elongation of old tiller after cut. Dry matter increase during regrowth had high correlation with tiller number and tiller elongation a week after cut, while it did not have any correlation with NSC at cutting stage or with consumption of NSC during regrowth. Therefore, regrowth in sorghum and pearmillet must depend upon activity of tiller primordia more than upon amount of reserved NSC.

• Korean Journal of Plant Resources
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• v.25 no.6
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• pp.745-752
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• 2012

Compared to wide ranges of genetic variation of natural populations, very limited Miscanthus cultivar has been released. This study was the first report on the development of Miscanthus cultivar by means of radiation breeding. Seeds of M. sinensis were initially exposed to gamma rays of 250 Gy for 24 h, generated from a $^{60}Co$ gamma-irradiator. The irradiated seeds were sown and then the highly tiller-producing mutants were selected for this study. Biomass-related parameters including tiller number, plant height, stem diameter, and leaf number were measured. Ploidy level and internal transcribed spacer (ITS) were investigated to characterize the mutants compared to wild type (WT) Miscanthus. Plant height and tiller number were negatively related, where multi-tillering mutants were relatively short after 4 month growth. However stem diameter and leaf number were greater in mutants. All the materials used in this study were diploid, implying that the mutants with greater tiller numbers and stem diameter were not likely related to polyploidization. Based on the sequence of ITS regions, the mutants demonstrated base changes from the gamma irradiation where G+C content (%) was decreased in the ITS1, but increased in ITS2 when compared to WT sequence. ITS2 region was more variable than in ITS1 in the mutants, which collectively allows identification of the mutants from WT. Those mutants having enhanced tillers and allelic variations might be used as breeding materials for enhanced biomass-producing Miscanthus cultivars.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.60 no.4
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• pp.412-420
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• 2015

Even though phosphorus (P) is essential element for plant growth and development, it is not enough for crop production in soil. To breed more P deficient tolerance rice, screening and selection in rice population is needed. We tried to develop more simple and rough screening method for breeding of P deficient tolerance rice. In P deficient condition, tiller number was dramatically decreased among yield components in rice. Though this result, we confirmed tiller number could be the best marker in screening of P deficient tolerance rice. 480 rice genetic resources were cultivated in rice bed tray filled with P deficient soil for four weeks and each dry weight was measured. Among them, the 55 kinds of genetic resource were selected then cultivated in paddy field with 3 fertilizer conditions. Plant dry weight and tiller number in ripening stage were shown significant difference according to P condition. Plant dry weight and tiller number in ripening stage was highly correlated especially in P deficient condition. Furthermore, the tiller number in ripening stage and plant dry weight in rough screening were shown high degree correlation. Though these results, we might expect measuring of plant dry weight after cultivation in rice bed tray filled with P deficient soil could be a simple and effective screening method in selection of P deficient tolerance rice.

• Journal of The Korean Society of Grassland and Forage Science
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• v.4 no.1
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• pp.13-17
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• 1983

This experiment was carried out in order to know the relationship between morphological characters and dry matter yield at vegetative growth stage in Meadow fescue grown under plant basis. 1. The dry weight of a plant (PW) indicated positive significant correlation with plant height (pH), leaf area (LA) and stem area (SA). It means that increase in dry of a plant was resulted from interactions among above morphological characters. 2. Stem area (SA) is an important morphological character for increasing the dry weight of a plant. 3. The varieties could be classified into 3 types based on plant type index (PTI, dry weight of a plant/ (no. of tiller)$^2$), it were M in tiller weight type, Leto, First and Trader in medium type and, Bundy and Tammisto in tiller number type, respectively. 4. The variety with tiller weight type had more havier tiller and larger stem thickness than those of variety with tiller number type. But, tiller number type showed higher plant height. 5. In order to obtain the highest yield in tiller weight type, there were necessary to increasing the number of tillers and higher plant height.

• Asian Journal of Turfgrass Science
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• v.7 no.1
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• pp.5-12
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• 1993

This experiment was conducted to study on the morphological change and growth retardation of Korean Lawograss (Zoysia japonica Steud.) under various shading degrees. Dada of plant height, No. of tiller, No. of stolon, No. of rhizome and fresh weight were measured on the l47days after transplanting in 1991. The results are summarized as follows. Plant height was increased at 30% shading degree or over, Maximum plant height was observed at 60% shadeing degree which was 24.2 cm. while full sunlight(control) was most shorted as 10.1 cm. Plant height rapidly was increased as to shading degree increase. The decreasing rate was lower in tiller number and stolon number(top parts of plant) compared with the rhizome number(under ground part) was severely decreased at 30% to 60% of shading. To increase the shading degree, rhizome number was most severely decreased under shading degrees. As degree of shading increase to 30%, 60% and 90%, fresh weight decrease to 66%, 44%, 22% to full sunlight, respectively. Relative growth retadation of Korean lawngrass was decreased by the order of number of rhizome, fresh weight, number of tiller, number of stolon. And these characters were highly significant accord-ing to the different shading degrees.

• Journal of The Korean Society of Grassland and Forage Science
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• v.13 no.2
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• pp.78-85
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• 1993

This experiment was carried out to select for the varieties with high environmental adaptability in mountainous pastures of Taekwalyong area, and the evaluation was based on the data of varietal differences of dry matter production and yield components in Tall fescue cutting at various developmental stages in growth period of autumn. The results were summarized as follows; 1. The varieties with high number of tillers per plant(NT) showed a high dry weight of plant(DW) in all autumn cuttings. These varieties(Barce1 and Fuego) may be more adaptable to mountainous pastures of Taekwalyon area than other varieties. 2. The number of tillers per plant(NT) was significantly positive correlated with dry weight of plant (DW), but dry weight of tiller(WT) was not significantly correlated with dry weight of plant(DW) in all autumn cuttings. 3. The multiple regression equations of autumn cutting stages with mean dry weight of plant(DW) and number of tillers per plant(NT) can be used to estimate the cutting time to obtain maximum mean dry weight of plant(DW) and the highest number of tillers per plant(NT). The maximum mean dry weight of plant(DW) and the highest number of tillers per plant(NT) was estimated at the time of 21 Oct. and 26 Oct, respectively. 4. Dead leaves tended to increase greatly after the 2nd cutting(l4 Oct.) in growth period of autumn. 5. The number of tillers per plant(NT) was an important yield component before tiller density achieved equilibrium, but dry weight of tiller(WT, including dead leaves) was of most significant as a yield determinant after maximum tiller density reached in growth period of autumn.