• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.3
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• pp.202-208
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• 2001

Under the constant daylength of 13 hours and growth temperatures of 15$^{\circ}C$ to 27$^{\circ}C$, the final number of loaves (FNL) on the main culm was constant as 15 regardless of temperature in rice variety 'Kwanganbyeo'. Leaf appearance rate (LAR) increased with rising temperature and decreased with phenological development. Threshold temperature (T$_{o}$) was not constant across growth stages, but increased with phenological development. Effective accumulated temperature (EAT), which is calculated by the summation of values subtracting T0 from daily mean temperature, is closely related with number of leaves appeared (LA). LA was fitted to bilinear, quadratic, power and logistic function of EAT. Among the functions, logistic function had the best fitness of which coefficient of determination was $R^2$=0.995. Therefore, LAR prediction model was established by differentiating this function in terms of time: (equation omitted). where dL/dt is LAR, T$_1$ is daily mean temperature, L is the number of leaves appeared, and a, b, and c are constants that were estimated as 41.8, 1098.38, and -0.9273, respectively. When predictions of LA were made by LAR prediction model using data independent of model establishment, the observed and predicted LA showed good agreement of $R^2$$\geq$0.99.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.3
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• pp.195-201
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• 2001

Sowing date experiments were carried out by employing a rice variety "Kwanganbyeo" in both field and phytotron with natural daylength. In phytotron, temperatures were controlled at daily mean of 21$^{\circ}C$ and 24$^{\circ}C$. The responses of final leaf number and beading date were analyzed in relation to daylength during photo-sensitive period (PSP). Based on the component models predicting the final leaf number and leaf appearance rate, a rice phenology model was established and verified. Days from sowing to flowering (DSF) were shortened and final number of leaves (FNL) increased as sowing dates were delayed from 25 April to 5 June in field and phytotron. The increased leaf appearance rate (LAR) and the reduced FNL, respectively, due to the higher temperature and the shorter daylength in delayed sowings in the field brought about greater shortening of DSF than in the phytotron where only FNL was reduced by shorter daylength in delayed sewings. FNL showed very close relationship with the average daylength during PSP of six-leaf stage to panicle initiation, being well fitted to the following rational function ($R^2$=0.98):(equation omitted) where D is daylength and a, b, and c are the constants that were estimated as 14.694, -0.992, and -0.068 in Kwanganbyeo, respectively. The rice phonology model, which was composed of two component models for LAR and FNL, predicted DSF very accurately. The differences between the observed and predicted DSF was less than two days in the sewing date field experiments in 1999 and 2000 of which data were not used for the model construction.struction.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.26 no.3
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• pp.273-277
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• 1981

This study was carried out in 1979 to establish the proper mulching culture method for an aromatic tobacco, ST 375-4. Three different methods of mulching were employed: Improved mulching (I. M.), General mulching (G. M.) and Non-mulching (N. M.). The number of seedlings per hole was 5 for I. M., and one for G. M. and N. M. In comparison with N. M., I. M. had shortened final date of leaf harvest by 14 days, enabling curing leaves before the rainy season. It also reduced transplanting labour hours by 44.9%. Yield and price value increased with improved mulching culture. There was little difference in relative light intensity at leaves between N. M. and I. M.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.3
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• pp.245-255
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• 1994

Weak persistence of white clover (Trifolium repens L.) under continuous grazing management has been limited its availability in the mixture with grasses. The experiment was carried out to determine the effect of defoliation interval on the regrowth and morphological characters of the clover cultivars. Individual plants of Regal (large leaf), Grasslands Huia (medium-small leaf) and Aberystwyth S184 (small leaf) were grown in 15cm plastic pot containing a 1: 2: 1 soil:sand:Promix mixture for 55 days, and then clipped to remove all fully expanded leaves every 7, 14 or 28 days. For the analysis of the cultivar response, plants were sampled on the final harvest date(0), and 1, 3, 7, 14 and 28 days after the final harvest date. Harvested dry weight of all cultivars declined as defoliation interval was increased, and that of Regal was the highest compared to the other cultivars. During the regrowing period, increase of total plant dry weight was due to that of leaf and petiole dry weight, and that of Osceola was greater than the others. Although total leaf area and mean single leaf area were increased during the regrowing period, they were reduced with increased defoliation interval and those of Osceola were the greatest until 14-days regrowth. S184 possessed the most number of leaves and Osceola did the longest petiole since 14-days regrowth although the more defoliation, the less nunber of leaves per plant and the shorter petiole. Stolon length and growing tips of all cultivars increased steeply during regrowth, while they were decreased with increased defoliation interval and those of S184 were the highest. More frequent defoliation had detrimental effects on regrowth of white clover, although larger leaf type was productive but less persistent in a mixture with grasses than smaller leaf type.

• Journal of Bio-Environment Control
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• v.6 no.2
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• pp.92-96
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• 1997

This study was carried out to clarify the effects of number of branches per pot on the growth and yield in long term bag-culture of sweet pepper. Two plants were grown in pot with four, six, and eight branches. The results are summarized as the followings : 1. Plant height, stem diameter, leaf dry weight, root dry weight, and stem dry weight did not significantly differ among treatments, while the number of leaves and leaf area were the greatest In the treatment with eight branches per pot. 2. Although fruit length was not influenced by the number of branches per pot, fruit diameter and fruit weight were greater with four branches per pot. The yield of the four branches was 124.5ton/ha, which was not significantly different from the yield of the eight branches, 113.4ton/ha. Considering the average fruit weight, fruit quality, and labor saving, four branches per pot appears to be appropriate. 3. Although the yield of eight branches per pot during the first five months was higher, however, four branches per pot should be recommended for the long term bag- culture of sweet pepper because the yield of the four branches from April, which is the middle stage of growth to the final harvest was higher than the yields of the others.

• Korean Journal of Plant Taxonomy
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• v.39 no.1
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• pp.4-11
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• 2009

Anatomical features of both leaves and stems of the four mistletoes in Korea (Viscum album var. coloratum, Korthalsella japonica, Loranthus yadoriki, L. tanaka) and of their secondary haustorial structure within several host plants were investigated. Among the four mistletoes, there were diagnostic characters of the anatomy of leaves and stems which enabled us to distinguish the four taxa. Leaves were observed to have three distinct characters including unifacial or bifacial leaves, the number of vascular bundles in the midveins, and the level of development of sclerenchyma cells. There were four diagnostic characters of stems: overall morphology of stems in transverse view, degree of cuticle development, arrangement of vascular bundles, and features of the sclerenchyma and pith. In order to determine secondary haustorial traits, the research focused on the seven host plants of L. yadoriki and on the five host plants of K. japonica. The following features were found to be important: presence or absence of an aerial runner root, the shape of the haustorial strand and flange, the degree of penetration into host tissues, and their development of shaft in transverse view, the development both of secondary haustorial cells and short tracheid in hyphae. Korthalsella japonica and L. yadorki were clearly distinguished by these characters. The secondary haustorial forms in each host were somewhat different, due to varying degrees of development in the strength of the host plants' wood. However, qualitative characters like the final position of the secondary haustorial penetration into host tissues and the development of short tracheid cells were not only affected by the degree of development of the host plants, but also useful for the systematic study.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.30 no.3
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• pp.314-319
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• 1985

In order to observe the differences of several characters related to earliness, seven barley varieties were tested under two different photoperiodic conditions. Final leaf number per main stem under long day did not vary among varieties, but ranged 6 to 7 in early group and 9 to 10 in late group under shortday. Shoot apex of early varieties, Jogangbori and Oweolbori reached to X stage at 24 days, but that of late variety, CI 15446 did to X stag at 32 days after transplanting under short day. Spike length reached to maximum length at 39 days in early group, but at 51 days in late group. Saeolbori, CI 15446 and Hangmi were photo-sensitive, but Jogangbori and Oweolbori were photo-insensitive. Therefore, the photoperiodic response to short day was most responsible to heading time. Those results showed that early heading varieties had the characteristics with less variation of final leaves, less retardation of shoot apex development and spike elongation, and shorter period to flag leaf emergence under short day.

• Journal of agriculture & life science
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• v.44 no.3
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• pp.1-6
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• 2010

The influence of sodium hypochlorite and ethephon on the germination of narrow-leaved purple coneflower (Echinacea angustifolia) was investigated. Treatment of seeds with ethephon (1 mM) for 2 h followed by soaking in 0.525% sodium hypochlorite greatly increased germination (>90%). The treatment of seed with a combination of sodium hypochlorite and ethephon shortened number of days required to reach 50% of the final germination ($T_{50}$) from 4.2 days in control to 1.1 days. Seedlings grown from ethephon-treated seeds had shorter and thicker hypocotyls and roots with higher dry weights compared to the control. The same trend was observed during seedling emergence from soil. Ethephon treatment longer than 2 h resulted in weaker seedlings, probably due to leaf senescence. Anthocyanin content in seedling leaves increased linearly from 0.04 mg/g fresh weight in control to 3.72 mg/g fresh weight in 24 h treatment as the time of seed exposure to ethephon increased. Seed treatment with bleach and ethephon may well be practiced to facilitate the establishment of E. angustifolia in the field.

• Korean Journal of Agricultural and Forest Meteorology
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• v.24 no.2
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• pp.78-82
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• 2022

Phenology determines the timing of crop development, and the timing of phenological events is strongly influenced by the temperature during the growing season. In process-based model, leaf area is simulated dynamically by coupling of morphology and phenology module. Therefore, the prediction of leaf appearance rate and final leaf number affects the performance of whole crop model. The dataset for the model equation was collected from SPA R chambers with five different temperature treatments. Beta distribution function (proposed by Yan and Hunt (1999)) was used for describing the leaf appearance rate as a function of temperature. The optimum temperature and the critical value were estimated to be 26.0℃ and 35.3℃, respectively. For evaluation of the model, the accumulated number of onion leaves observed in a temperature gradient chamber was compared with model estimates. The model estimate is the result of accumulating the daily increase in the number of onion leaves obtained by inputting the daily mean temperature during the growing season into the temperature model. In this study, the coefficient of determination (R²) and RMSE value of the model were 0.95 and 0.89, respectively.

• Journal of Bio-Environment Control
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• v.11 no.4
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• pp.205-216
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• 2002

This study was conducted to examine the effect of long-day (LD) period before short-day (SD) treatment on the vegetative growth of greenhouse-grown cut chrysanthemum cv. Reagan Improved at Wageningen Agricultural University, The Netherlands. Rooted cuttings of cut chrysanthemum cv, Reagan Improved were transplanted on 6th, 13th, 20th of September and all of them were treated with LD before SD treatment on 27th of September, The periods from transplanting until final harvest were 70, 77, and 84 days for 1, 2, and 3 week-LD treatment, respectively. The final plant height increased in the plot of 3 week-LD period and decreased in the plot of 1 week-LD period before the SD treatment. Total fresh weight and the leaf area were increased more in the plot of 3 week-LD period than that of 1 week-LD period, but the absolute growth rate after SD treatment was the same on plant growth rate and increase of the number of leaves in all treatments. The final dry matter production (g.m$^{-2}$ ) was increased more in the plot of 3 week-LD period than that of 1, 2week-LD period before SD treatment. Plant height and fresh weight were followed by the condition of LD period. In addition, dry mass production was highest in 3 week-LD period.