• 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 Agricultural and Forest Meteorology
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• v.11 no.4
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• pp.213-220
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• 2009

In order to predict the risk of freeze injury for 'Changhowon Hwangdo' peach trees, we used the dormancy depth (i.e., the daily chill unit accumulation during the overwintering period) as a proxy for the short-term, physiological tolerance to freezing temperatures. A Chill-days model was employed and its parameters such as base temperature and chilling requirement were optimized for peach trees based on the 12 observational experiments during the 2008-2009 winter. The model predicted the flowering dates much closer to the observations than other models without considering dormancy depth, showing the strength of employing dormancy depth into consideration. To derive empirical equations for calculating the probabilistic freeze risk, the dormancy depth was then combined with the browning ratio and the budburst ratio of frozen peach fruit branches. Given the exact date and the predicted minimum temperature, the equations calculate the probability of freeze damages such as a failure in budburst or tissue browning. This method of employing dormancy depth in addition to freezing temperature would be useful in locating in advance the risky areas of freezing injury for peach trees production under the projected climate change.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.14
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• pp.173-189
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• 1973

The followings are the results obtained in a series of experiments concerning of the varieties, the short-day-treatment, the fertilizer application, and the planting space of soybean, which were carried out to investigate the methods best suited for cultivating green soybean as the preceding crop of the rice. in the paddy-field in the middle parts of Korea at the practice farm attached to Agriculture College of Kon Kuk University in 1972. 1. Though the varieties of soybean was planted on the hot-bed on March 15 and then set in the main plot, none of them did flower within May 15, which is the limit time of flowering in growing soybean as the preceding crop of the rice in the paddy-field without the short-day-treatment being applied during raising seedlings. 2. The earliest-maturing variety groups such as HOKKAl#l, WASEMIDORI, YAEHUSANARI, MIT AKARAHAKUCHO, and VERDE flowered within May 15 by the short-day-treatment during raising seedlings. 3. The optimum hours of the day length was known to be 7 to 9 in the medium-maturing and late-maturing variety groups and 7 to 11 in the early-maturing and the earliest-maturing variety groups in the case of appling the short-day-treatment for 10 days from the beginning of the primary regular compound leaf development. 4 The optimum days in appling the short-day-treatment for 11 hours a day was recognized to be about 10 days regardless of the maturity of varieties. 5. Reduction of days required to flower by the short-clay-treatment, that is, light-sensitivity was remarkably higher in the medium-maturing and the late-maturing variety groups than in the earliest-maturing and the early-maturing variety groups. 6. The yield showed an increase of about 17 per cent in the case of appling the standard amount of nitrogen(4.0 kg/10 a), but it tended to reduce on the contrary in appling the increased amount of nitrogen. 7. The application of increased amount of phosphate had less significant effect on the yield increase than in the case of application of its standard amount( 4.0 kg/l0 a). 8. When the number of transplantation plant was changed from 54 to 130 per 3.3 $m^2$, the yield in 130 plant plot was about two times so higher than in 54 plant plot that the effect of close planting cultivation on the yield was proved to be remarkable. 9. Conditions possible for cultivating green soybean as the preceding crop of the rice in the paddy-field in the middle parts of Korea are turned to be as follows: (a) to plant the earliest-maturing-variety groups on the hot-bed on March 15. (b) to apply the short-day-treatment by 11 hours a day for 16 days from April 16, which is about the time when the primary regular leaf begin to develop. And it was, found to be a most remarkable in the increased yield that apply nitrogen 4.0 kg, phosphate 4.0 kg, and potassium 6.0 kg per 10 a as basic manuring totally and apply the close planting by 130 plants per $3.3{m^2}$(50 cm $\times$ 5 cm).

• 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.

• Korean Journal of Breeding Science
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• v.50 no.4
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• pp.453-462
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• 2018

This study was carried out to investigate the utilization value of legume crops collected in tropical and subtropical areas. We examined agronomic traits to assess domestic adaptability and evaluated useful components of foreign legumes. We used a total of 201 genetic resources of three legumes, consisting of 68 lentils, 72 chickpeas and 61 guars. The average number of days to flowering of the three legumes ranged from 56.7 to 60.8 days; the shortest in guar and longest in chickpea. The average number of days to growth of the three legumes ranged from the shortest 86.8 days in lentil, to the longest 163.9 days in guar. The maturation period of the three legumes lasted from the end of May until mid-September, based on sowing in March. However, the average yield of lentil was very low, ranging from 0.5 g to 30.6 g, with an average 16.4 g based on 10 plants per accession. The average 100 seed weight of the three legumes was 2.2 g for lentil, 22.9 g for chickpea, and 3.8 g for guar. The crude protein content ranged from 14.1% to 32.4% with an average of 20.4%, the highest for guar and the lowest for chickpea. The average crude oil content in the three legume crops was generally low, ranging from 0.8% in lentil, to 4.3% in chickpea. The average dietary fiber content in the three legume crops varied from 15.7% to 50.7%. Guar was the highest source of fiber, followed by chickpea (19.3%) and lentil (15.7%). From the agricultural traits analysis, chickpea and guar could grow domestically. However, lentil was difficult to flower and fruit normally during the warmer season after May. Therefore, lentil should be considered for late summer cropping during the cool season. The physicochemical properties of the three legumes seem to be useful as they are similar to, or better than, those of the control common bean.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.3
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• pp.534-544
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• 2017

In order to use the sea flowering plant, Zostera marina, as a cosmetic ingredient, this study was conducted to evaluate its antioxidant effect. We confirmed the formulation stability of the emulsion containing Zostera marina extracts. We studied the antioxidant activity of the dissolved Zostera marina extracts through the DPPH (1,1-Diphenyl-2-picrylhydrazy) radical scavenging activity assay and SOD (superoxide dismutase)-like activity assay. Also, the pH, viscosity and particle dispersion of the emulsion containing Zostera marina extracts were measured using a Turbiscan LAB. The emulsions were measured at one-week intervals in a thermostat chamber ($25^{\circ}C{\pm}1^{\circ}C$, $40^{\circ}C{\pm}1^{\circ}C$) for 28 days. The extracts of Zostera marina showed a DPPH radical scavenging rate of 86.21% and SOD-like activity of 99.24% at 5.00 mg/ml and exhibited a dose-dependent increase in their antioxidant activity. We measured the stability of the pH, viscosity and emulsion particles using the Turbiscan LAB in a thermostat chamber for 28 days. The formulations to which the Zostera marina extracts were added were considered to be stable, due to their negligible physical property changes over time during storage. The results suggest that the Zostera marina extracts with 70% ethanol (v/v) could be used in cosmetics as an antioxidant for the anti-aging of skin.

• Korean Journal of Organic Agriculture
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• v.11 no.4
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• pp.103-115
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• 2003

In order to investigate the possibility for use to control environmental pollution, Kenaf(Hibiscus cannabinus L.) was used to obtain information of their growth and $CO_2$ response under different temperatures and $CO_2$ concentration. The highest percentage of germination and aboveground dry mass of Kenaf were found at 30$^{\circ}C$ and 35$^{\circ}C$ by 89.0% and 3.2g, respectively under different temperatures. The amount of $CO_2$ absorption and aboveground dry mass production of Kenaf were higher than those of maize during the whole growing period and the last sampling of aboveground dry mass of Kenaf and maize were 252.9g and 200.8g, respectively. The highest plant height was found at 400ppm by 131.0cm and the next was in the order of 600ppm by 1293cm, and 800ppm by 108.8cm. Leaf area was higher in the order of 400ppm > 600ppm > 800ppm, whereas leaf dry mass was in the order of 800ppm > 600ppm > 400ppm under different $CO_2$ concentration, showing that leaf became thicker as $CO_2$ concentration was increased. Days from seeding to flowering became shorter by 13 days in 35/25$^{\circ}C$ compared with 25/15$^{\circ}C$ between two temperature regimes and they also became shorter as $CO_2$ concentration was increased. Aboveground dry mass was higher in 35/25$^{\circ}C$ than that of 25/15$^{\circ}C$ between two temperature regimes. while it was increased in the order of 800ppm > 600ppm > 400ppm as CO2 concentration was increased. Temporal changes of leaf dry mass during growth period showed no difference between $CO_2$ concentration in 25/15$^{\circ}C$ , but the highest of it was found at 800ppm in 35/25$^{\circ}C$. The highest temporaI increase of root dry mass was found at 800ppm in 25/15$^{\circ}C$, but 35/25$^{\circ}C$ showed no difference between different $CO_2$ concentration.

• Journal of The Korean Society of Grassland and Forage Science
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• v.9 no.3
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• pp.179-186
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• 1989

According to the results from the experiments of selecting a suitable variety of forage rape and comparing productivity and nutrient quality between forage rape and oil seed rape, Velox appeared to be the most suitable variety in terms of productivity and nutrient quality at the southern area of Korea among the varieties used in the experiments. Consequently, Velox was grown under two different cultural methods, individual culture and population culture, and productivity and variation of nutrient quality during the growth period were observed and compared between the cultural methods. The results from the experiment are summarized as follows: 1. Although variations were great in plant fresh weight and plant dry matter weight among plants, individual culture showed significantly higher value in these characters at the 1 % level than population culture. Plant fresh weight and plant dry matter weight were largely dependent upon the amount of branches in case of individual culture. However, in population culture, they were equally dependent upon the amount of branches and main stem. There was no significant difference in dry matter percentage between cultural methods, and main stem showed highest dry matter percentage. 2. Content of crude protein was decreasing gradually as plants continued to grow. Individual culture showed higher content of crude protein than population culture from 90 to 120 days after sowing but vice versa from 180 days after sowing to flowering stage. Contents of fiber such as NDF, ADF, cellulose and lignin was low at the early stage of growth. It was increasing gradually as plants grew older and at the latter stage of growth plants under individual culture showed higher values in contents of fiber. 3. In vitro dry matter digestibility (IVDMD) of both stems and leaves was decreasing gradually as plants grew older. Plants under individual culture showed higher IVDMD of stems than plants under population culture, but no significant difference in IVDMD of leaves was observed between cultural methods.

• Journal of The Korean Society of Grassland and Forage Science
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• v.39 no.1
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• pp.9-16
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• 2019

This study was carried out to investigate the effects of seeding dates and cultivated period on the growth characteristics, dry matter yield and feed value of Teosinte new variety "Geukdong 6"[Zea mays L. subsp. mexicana (Schrad.) H. H. Iltis]for feed. The experimental design was arranged in a randomized block design with three replications. Treatments consisted of five time seeding dates, 10 May(T1), 25 May(T2), 10 June(T3), 25 June(T4) and 10 July(T5), and same time harvesting, 22 October. Therefore, growing period were 164 days(T1), 149 days(T2), 134 days(T3), 119 days(T4) and 103 days(T5), respectively. In growth stage at harvest time, T1, T2, T3, T4 and T5 were early flowering, end heading, middle heading, early heading and early heading stage, respectively. Plant length and dead leaf were highest in T1, but leaf width and number of leaf were highest in T2 than others (p<0.05). Leaf length, stem diameter and number of tiller were not significantly different among the treatments (p<0.05). Stem hardness was higher in order of T1(2.0)> T2(1.9) > T3=T4(1.7) > T5($1.2kg/cm^2$). Fresh yield and dry matter yield showed significantly higher as the sowing time was faster and the cultivation period was longer (T1 > T2 > T3 > T4 > T5, p<0.05). Crude protein, crude fat and TDN content were highest in T5, but ADF and NDF content were highest in T1 than others (p<0.05). T1, T2 and T3 showed significantly higher crude protein yield compared to T4 and T5 (p<0.05). Total digestible nutrients yield were higher in order of T1 > T2 > T3 > T4 > T5 (p<0.05), and relative feed value were higher in order of T5 > T4 > T3 > T2 > T1 (p<0.05). Based on the above results, seeding dates could be recommended from the early May to the late May, and it is efficient that the cultivation period is over 150 days for dry matter yield, crude protein yield and total digestible nutrients yield.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.1
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• pp.64-69
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• 2008

The objective of experiment was to investigate the effects of planting density on growth and yield of vegetable soybean, and to clarify the optimum planting density of vegetable soybean in the middle west region of Korea. The field experiment with 4 levels of planting density was carried out at Yesan area in $2005{\sim}2006$. The days from seeding to flowering and the days from seeding to harvesting and lodging were not significantly different among planting distance. The stem length was increased as planting distance was shortened but the number of node, branch, pod per branch, pod per individual, weight of stem and pod, one hundred pod weight and rate of 2+3 seed per pod were decreased as planting density was increased. The size of vegetable soybeans was not significantly different among planting distance, but the harvest index of vegetable soybean was decreased as planting distance was shortened. Yield of vegetable soybean was increased as planting distance was decreased. However, the approriate densities for stem and pod weight per a plant, number of pod per a branch and the vegetable soybean yield of 2+3 seed per pod were different from that density. The optimal planting distance of varieties was $60{\sim}25\;cm$ in Sunheukkong and Ilpumgeomjeongkong and was $60{\sim}35\;cm$ in Galmikong.