• Current Research on Agriculture and Life Sciences
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• v.6
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• pp.49-69
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• 1988

In order to develop a cropping system that can produce garlic in the period of short supply from March to April, effects of low temperature treatment of seed bulbs and planting dates, starting date of low temperature treatment, days of low temperature treatment on plant growth, maturity and yield were studied in Southern strain, 'Namhae' and in Northern strain, 'Euiseong' of garlic (Allium sativum). The results obtained were as follows. In Sorthern strain, sprouting was significantly enhanced by low temperature treatment only in Sep. 14, and Sep. 29 plantings. Days to sprout were least in 30 days of low temperature treatment of Sep. 14 planting and in 45 days treatment of Sep. 29 planting. When considering on the beginning date of low temperature treatment, a marked difference was observed between treatments started before July 31 and after Aug. 15. Sprouting was most enhanced in 45 days low temperature treatment of Aug. 15 and Aug. 30 plantings. In Northern strain, sprouting was en hanced by low temperature treatment in planting from Sep. 29 to Nov. 13 and low temperature treatment for 60 days was most effective. Effect of low temperature treatment on early plant growth was observed in Sep. 14 and Sep. 29 plantings, but the effect on plant growth at intermediate stage or thereafter was observed in up to Oct. 29 plantings. Optimun days for low temperature treatment on growth enhancement was 45 and 60 days in Southern strain and 60 days in Northern strain in each planting dates. In Southern strain, the longer the low temperature treatment and the later the planting date the less the number of leaves developed. In Northern strain, normal leaves were not developed in plantings from Sep. 14 to Nov. 13. In Southern strain, clove differentiation and bulbing were earlist in 45 and 60 days treatment of Sep. 14, Sep. 29, and Oct. 14 planting initiated on July 31 and Aug. 15. In Northern strain, clove differentiation and bulbing were earlist in 60 days treatment of Oct. 14 planting initiated on Aug. 15 and Aug. 30. In treatment initiated later than above, longer the low temperature treatment the earlier the clove differentiation and bulbing in both Southern and Northern strains. The earlier the initiation date and the longer of low temperature treatment, the earlier bolting in southern strain. In Northern strain, bolting was most enhanced in 45 and 60 days of low temperature treatment initiated on Aug. 15 and Aug. 30. The longer the low temperature treatment in plantings thereafter, the earlier the bolting. The earlier the planting date garlic bulbs. Harvest date was earliest in 45 and 60 days low temperature treatment started from July 31 to Aug. 30 in Southern strain, and it was in 60 and 90 days low temperature treatment initiated from July 31 to Aug. 30 in Northern strain. Bulb weight was heaviest in 45 days low temperature treatment of Oct. 14 planting and next was in 45 days treatment of Sep. 29 planting in Southern strain. In Northern strain, bulb weight was heaviest in 60 days treatment of Oct. 14 planting and next was in 45 days treatment of Oct. 14 planting. When considered in the aspect of the beginning date of low temperature treatment, bulb weight was heaviest in 45 days treatment started on Aug. 30 in Southern strain and in 60 days treatment started on Aug. 15 in Northern strain. A high negative correlation between days to harvest and plant height on January 12, and a high positive correlation between days to harvest and days clove differentiation were observed. This indicates that enhanced plant growth and clove differentiation induced by low temperature treatment advanced the harvest date. A high negative correlation between bulb weight and days to clove differentiation, days to harvest suggests that the enhanced clove differentiation result and in heavier bulb weight. From the above results, it suggested that early crop of garlic can be harvested by planting at the period of Sep. 29 to Oct. 14 after 45 days of low temperature treatment of seed bulbs of Southern strain. Then harvest date can be shortened by 30 days compared to control and garlic can be harvested in early April.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.26 no.1
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• pp.1-31
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• 1981

Experiments were conducted to investigate rice varietal response to low water and air temperatures at different growth stages from 1975 to 1980 in a phytotron in Suweon and in a cold water nursery in Chooncheon. Germination ability, seedling growth, sterility of laspikelets, panicle exertion, discoloration of leaves, and delay of heading of recently developed indica/japonica cross(I/J), japonica, and indica varieties at low air temperature or cold water were compared to those at normal temperature or natural conditions. The results are summarized as follows: 1. Practically acceptable germination rate of 70% was obtained in 10 days after initiation of germination test at 15\circ_C for japonica varieties, but 15 days for IxJ varieties. Varietal differences in germination ability at suboptimal temperature was greatest at 16\circ_C for 6 days. 2. Cold injury of rice seedlings was most severe at the 3.0-and 3.5-leaf stage and it was reduced as growth stage advanced. A significant positive correlation was observed between cold injury at 3-leaf stage and 6-leaf stage. 3. At day/night temperatures of 15/10\circ_C seedlings of both japonica and I/J varieties were dead in 42 days. At 20/15\circ_C japonica varieties produced tillers actively, but tillering of I/J varieties was retarded a little. At 25/15\circ_C, both japonica and I/J varieties produced tillers most actively. Increase in plant height was proportional to the increase in all varieties. 4. In I/J varieties the number of differentiated panicle rachis branches and spikelets was reduced at a day-night temperature of 20-15\circ_C compared to 25-20 or 30-25\circ_C, but not in japonica varieties although panicle exertion was retarded at 20-15\circ_C. The number of spikelets was not correlated with the number of primary rachis branches, but positively correlated with that of secondary rachis branches. 5. Heading of rice varieties treated with 15\circ_C air temperature at meiotic stage was delayed compared to that at tillering stage by 1-3 days and heading was delayed as duration of low temperature treatment increased. 6. At cold water treatment of 17\circ_C from tillering to heading stage, heading of japonica, I/J, and cold tolerant indica varieties was delayed 2-6, 3-9, and 4-5 days, respectively, Growth stage sensitive to delay of heading delay at water treatment were tillering stage, meiotic stage, and booting tage in that order, delay of heading was greater in indica corssed japonica(Suweon 264), japonica(Suweon 235), and cold tolerant indica(Lengkwang) varieties in that order. Delay of heading due to cold water treatment was positively correlated with culm length reduction and spikelet sterility. 7. Elongation of culms and exertion of panicles of rice varieties treated with low air temperature 17\circ_C. Culm length reduction rate of tall varieties was lower than that of short statured varieties at low temperature. Panicle exertion was most severaly retarded with low temperature treatment at heading stage. Generally, retardation of panicle exertion of 1/1 varieties was more severe than that of japonica varieties at low temperature. There was a positive correlation between panicle exertion and culm length at low temperature. 8. The number of panicles was increased with cold water treatment at tillering stage, but reduced at meiotic stage. As time of cold water treatment was conducted at earlier growth stage, culm length was shorter and panicle exertion poorer. 9. Sterility of all rice varieties was negligible at 17\circ_C for three days but 30.3-85.2% of strility was observed for nine-day treatment at 17\circ_C. Among the tested varieties, sterility of Suweon 264 and Milyang 42 was highest and that of Suweon 290 and Suweon 287 was lowest. The most sensitive growth stage to low temperature induced sterility was from 15 to 5 days before heading. There was positive correlation between sterility of rice plants treated with low temperature at meiotic and heading stage. 10. Percentage of spikelet sterility was greatest at cold water treatment at meiotic stage (auricle distance -15～-10cm) and it was higher in 1/1 (Suweon 264, Joseng tongil), japonica (Nongbaek, Towada), and cold tolerance indica(Lengkwang) varieties in the order. Level of cold water and position of young-ear affected on the sterility of varieties at meiotic stage; percentage of spikelet sterility of variety, Lengkwang, of which young-ear was located above the cold water level was high, but that of short statured variety, Suweon 264, of which young-ear was located in the cold water was lower. 11. Percentage of ripened grains was not reducted at 15\circ_C air temperature for three days at full heading stage in all varieties. However, at six-day low temperature treatment Suweon 287, Suweon 264 showed percentage of ripended grains lower than 60%, but at nine-day low temperature treatment all varieties showed percentage of ripened grains lower than 60%. Low temperature treatment of 17\circ_C from 10 days after heading for 20 days did not affect on the ripening of all varieties. 12. Uptake of nitrogen, phosphorous, potassium, calcium, and magnesium in whole plants was higher at average air temperature of 25\circ_C, but concentration of the elements was lower compared to those at 19\circ_C. However, both total uptake and concentration of manganese were higher at 19\circ_C compared to 25\circ_C. 13. Higher application of nitrogen, phosphorus, silicate, and compost increased yield of rice due to increased number of panicles and spike let fertility in cold water irrigated paddy.

• Journal of the Korean Institute of Landscape Architecture
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• v.37 no.4
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• pp.64-71
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• 2009

Excessive soil organic matter (SOM) is detrimental to turfgrass quality when used intensively in sand-based root zones, thereby affecting the sustainability of turfgrass systems. As part of a major project examining the sustainable management of SOM on golf greens, microbial decomposition on soil organic matter accumulation with depth was assessed and the effect of soil air-condition improvement and Ca fertilization was investigated by soil microbial respiration (SMR). Three soil samples from three depths(0~5, 5~10, and 10~15cm) of 5 year and 30 year old green were analyzed for SOM content. In 30 year old green, SMR and dehydrogenase activity(DHA) were analyzed to assess the soil microbial decomposition with depth. It was then divided into 4 plots: untreated as a control, dolomite-treated, 0~5cm deep section-removed, and 0~5 cm deep section-removed+dolomite-treated. After treatment, three soil samples were taken at 1, 2 and 4 weeks by the above-mentioned method, and analyzed for SMR to better understand SOM decomposition. SOM accumulation in the 0~5cm depth of golf greens can be controlled by intensive cultivation such as coring, but below 5cm is more difficult as the results showed that SOM content below 5cm increased over time. Soil microbial decomposition of organic matter will be necessary to reduce SOM accumulation, but SMR below 5cm was low and wasn't significantly altered by increasing exposure to air and fertilizing with Ca. As a result, aeration treatments such as coring and Ca fertilization might not be effective at improving soil microbial decomposition below 5cm depth in aged greens.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.2
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• pp.399-404
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• 2004

This study was conducted to investigate the effect of monosodium glutamate (MSG) and fermentation methods (C-I; fermented for 5 days at 1$0^{\circ}C$ after 2$0^{\circ}C$ fermentation for 2 days, C-II; fermented for 7 days at 1$0^{\circ}C$, M-I; kimchi with MSG fermented for 5 days at 1$0^{\circ}C$ after 2$0^{\circ}C$ fermentation for 2 days, M-II; kimchi with MSG fermented for 7 days at 1$0^{\circ}C$ on fermentation and free amino acid content. Fermentation of M-I and M-II was slightly delayed compared to C-I and C-II. Total microbe of C-I and C-IIwere lower than those of M-I and M-II, and lactic acid bacteria of C-I and C-II were lower than those of M-I and M-II respectively. The major free amino acids were alanine, asparagine, homocystine and valine in C-I, especially, glutamic acid and ornithine were high in C-II. Homocystine, alanine, asparagine and valine in M-I, glutamic acid, alanine, hydroxyproline, asparagine, homocystine, ornithine and valine were the major free amino acid in M-II, respectively. The sour taste of M-I and M-II was lower than those of C-I and C-II, respectively, and the effect of delaying fermentation at 1$0^{\circ}C$ did not showed in the C-I and M-I. The crispy taste of the M-I and M-II was higher than those of C-I and C-II, which was the opposite results of sour taste. Palatable and overall taste of M-I and M-II were higher than those of C-I and C-II, respectively These results suggest that the MSG in kimchi affect not only increment of free amino acid content but also shelf-life and taste improvement, and continuous fermentation at 1$0^{\circ}C$ also enhance the content of free amino acid and shelf-life of kimchi.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.35 no.4
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• pp.352-361
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• 1990

The reducing effect of wind injury was investigated using several wind-break nets in Youngdeok province where cold-wind damage is often occurred during rice growing season. The white-head damage of rice have been often occurred by typhoon during the period between August 15 to September 10 in the cold wind area of the eastern coastal during the last 11 years (1979-1989). This may suggest that the critical period for heading will be by August 15 in the regions. High evaporation coefficient, more than 250 due to typhoon passage over the regions resulted high injury of white head. Generally, the wind injury have been caused by warm and dry westerlies through Fohn apperance in Taebaeg mountains and by cool-humid wind which blows from coast to inland. The frequency of occurrence of the two types of typhoons were 25, 20%, respectively during rice cultivation. The instalation of wind-break net significantly reduced the wind blowing speed, depending on the net mesher with the higher effect in dence net. The distances between the net and cropping area also affect the wind speed: 23% reduction at 1m distance. 34% at 10m and 28% at 20m, respectively. The reducing effect was also observed even at 10 times height of the wind-break net. The instalation of wind-break net gave several effects on climate factor, showing that temperature increased by 0.8$^{\circ}C$(maximum), 0.7$^{\circ}C$(minimum), 0.6$^{\circ}C$(average) : water temperatures increased by 0.5$^{\circ}C$(maximum), 0.6$^{\circ}C$(minimum), 0.5$^{\circ}C$(average) : soil temperature increased 0.4$^{\circ}C$. The earlier heading and increasing growth rate, use of light, culm length, panicle number per hill, spikelet number per panicle, fertility and 1,000 grain weight were observed in the fields with the wind-break nets resulting in 10-15% increase in rice yield using 0.5${\times}$0.5cm nets. The increasing seedlings per hill gave higher grain yield by 13% in the cold wind damage regions of eastern coastals. and the wind-break was more significant in the field without the wind-break net. Wind injury of rice plant in the cold wind regions of eastern coastals in korea could be reduced by selection of tolerant varieties to wind injury, adjustment of transplanting time, and establishment of wind-break nets.

• Journal of The Korean Society of Grassland and Forage Science
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• v.4 no.3
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• pp.206-211
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• 1984

The influence of fertilizer on the growth characteristics in Korean lawn grass was studied from June through October in a experiment. The results were as follows: 1. Maximum dry matter weight of Korean lawn grass was achieved in early in early August when it was $64.3g/m^2$ without fertilizer and $157.9g/m^2$ with fertilizer. On the other hand, the dry matter weight of whole plant including Korean lawn grass reached the maximum in late September, which was late, to some extent, compared with that if pure Korean lawn grass, presumably associated with seed maturing period of $C_4$ type plants. 2. Notable positive effect on leaf blade and non-leaf part weight in Korean lawn grass was also detected. However, the rate of dry matter occupied by non-leaf part was markedly increased by fertilizer application. 3. The dry matter portion occupied by Korean lawn grass the in total dry matter weight of whole plant was significantly decreased as time went by, particularly in case of fertilizer application. 4. Fertilizer, which might imply an increased potential of tiller numbers according to fertilizer. 5. In general, the seasonal change pattern of the rhizome of Korean lawn grass coincided with that of the aboveground organs: Its maximum dry matter weight achieved from late August to early September was $194.2g/m^2$ with nil fertilizer, and, with fertilizer, $259.7g/m^2$, of which figures were equivalent to be increased to 33.7%, compared to that with nil fertilizer. Applying fertilizer increased the weight of root: The highest values were $36.7g/m^2$ with nil fertilizer and $80.9g/m^2$ with fertilizer.

• Korean Journal of Soil Science and Fertilizer
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• v.17 no.4
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• pp.389-398
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• 1984

The effect of N forms ($NO_3{^-}-N$, $NH_4{^+}-N$) and concentrations (4, 8, $16meq/{\ell}$) which were changed at head formation stage on the tip-burn incidence of chinese cabbage was studied under the three levels (0, 8, 16 meq/l) of Ca. All of the plants grown on $NH_4{^+}-N$ showed the symptoms of tip-burn and low yields regardless of Ca levels. Roots of plants grown on $NH_4{^+}-N$ were severely damaged. The pH of the leachate from $NH_4{^+}-N$ pot was decreased to below pH 5. Plants which had been grown on $NH_4{^+}-N$ before the head formation stage, but changed to $NO_3{^-}-N$ were recovered from abnormal growth. But, the reverse showed the tip-burn symptoms. $NH_4{^+}-N$ treatments increased the T-N contents, but lowered K and Ca contents of inner leafblades. Icreased applications of Ca did not affect the T-N and K contents of the inner leafblades. $NH_4{^+}-N$ suppressed Ca translocation into the inner leaves from outer leaves after the head formation stage, but $NO_3{^-}-N$ accelarated it. Ca contents were much lower in leaves showing tip-burn symptoms than in healthy leaves. Internal rot which is a tip-burn symptom occuring after head formation were noted in plants applied with high concentration of $NO_3{^-}-N$ both before and after the head formation stage. Ca contents correlated well with the rates of Ca application, but there was no correlation between ca conents and internal rot incidence. Chinese cabbage tip-burn is not caused by Ca deficiency, as is commonly believed, but rather by the water stress (95% water contents in $NO_3{^-}$-fed plants, 91% in $NH_4{^+}$-fed plants) resulting from root damage caused by ammonium toxicity. Internal rot is also caused by excess applications of nitrogen, and is unaffected by calcium levels.

• Asian Journal of Turfgrass Science
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• v.15 no.2
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• pp.51-64
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• 2001

Summer stress is one of the serious problems on cool-season grass at the soccer fields in Korea during heavy rainy season. This study was conducted to intestigate the effect of shade net with regard to its percent (0, 50, 75), color (black, green), height (0 cm, 30 cm) and time (7 hr, 24 hr) on turf canopy temperature, light intensity, leaf color, turf performance, clipping yield and root dry weight of cool-season turfgrass. Turf canopy temperature was 6~13$^{\circ}C$ under black and green shade net when temperature was over 4$0^{\circ}C$. Light intensity was also decreased from 40 to 94% under black and green shade net compared to control. Black shade net was more effective than green net in reduction of temperature and light intensity. Green shade net was found to be better for photosynthesis of cool-season grass. Leaf color, turf performance, clipping yield, and root dry weight were better and increased under 50% and 75% shade net. 50% black shade net with 30cm height and 7 hr treatment showed the best turf performance. It can be concluded that 50% and 75% green shade net can be used fur reducing summer stress on cool-season grass after soccer marches during heavy rain season. The shade net decreased the turf canopy temperature and reduced heating damage of cool-season turfgrass.

• Korean journal of applied entomology
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• v.26 no.4 s.73
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• pp.229-237
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• 1987

In order to study the biological control of soil-borne disease of sesame, antagonistic isolates of Trichoderma , Bacillus sand streptomyces to Fusarium oxysporum and Rhizoctonia solani were isolated from the rhizosphere soils of sesame plants and some other habitats. Out of the isolates of microorganisms collected a strain of Trichoderma viride was selected as a biological control agent for the study and its effect on the control of damping-off and the seedling growth of sesame was investigated. The results obtained are as follows: 26 percents of Bacillus spp. isolated from the rhizosphere soil of sesame plants showed antagonism to two pathogenic fungi. Important species were B. Subtilis and B. polymyxa. Streptomyces species isolated from the rhizosphere soils of sesame lysed the cell wall of hyphae and conidia of F. oxysporum and reduced conspicuously the formation of macroconidia and chlamydospores of the fungus. 84 percents of Trichoderma spp. isolated from the rhizosphere soil of sesame plants were antagonistic to F. oxysporum and 60 percents of the isolates were antagonistic to both F. oxysporum and R. solani. Trichoderma viride TV-192 selected from antagonistic isolates of Trichoderma spp. was highly antagonistic to F. oxysporum and soil treatment with the isolate reduced notably damping-off of sesame. T. viride TV-192 showed better growth in crushed rice straw, barley straw and sawdust media than F. oxysporum. Sawdust was selective for the growth of T. viride. Supplementation of wheat bran and mixtures of wheat bran and sawdust inoculated with T. viride TV-192 in the soil reduced remarkably damping-off of sesame by F. oxysporum but high density of the fungus TV-192 caused the inhibition of seed germination and seedling growth of sesame. Inhibitory effects of Trichoderma species on seed germination and seedling growth of sesame were different according to the isolates of the fungus. Normal sesame seedlings on the bed treated with the fungus showed better growth than not treated seedlings.

• Journal of Plant Biotechnology
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• v.42 no.3
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• pp.215-222
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• 2015

The radish (Raphanus sativus L.) is an important Brassicaceae root vegetable crop worldwide. Several studies have been conducted concerning radish breeding. There are major challenges to prevent premature bolting in spring plantings. Here, we performed the characterization of two inbred radish lines which vary in bolting time. "Late bolting radish" (NH-JS1) and "early bolting radish" (NH-JS2) were generated by a conventional breeding approach. The two inbred lines showed different bolting phenotypes depending on vernalization time at $4^{\circ}C$. NH-JS1, the late bolting radish, was less sensitive to cold treatment and the less sensitivity was inversely proportional to the duration of the vernalization. We also measured gene expression levels of the major bolting time related genes in the NH-JS1 and NH-JS2 lines. RsFLC1 plays a central role in the timing of flowering initiation. It is a strong repressor and it's transcript is highly expressed in NH-JS1 compared to NH-JS2 under no treatment and vernalization conditions. RsFRI, a positive regulator of RsFLC, is also highly expressed in NH-JS1 compared to NH-JS2 regardless of vernalization. In contrast, RsSOC1, suppressed by FLC as a floral integrator gene, showed the most difference, a 5-fold increase, between NH-JS1 and NH-JS2 under vernalization conditions. From these results, we conclude that NH-JS1 showed a late flowering phenotype after cold treatment due to the expression differences of flowering time regulator genes rather than difference sensitivity to cold. These results may be useful to understand the control mechanisms of flowering time and may help identify molecular markers for selecting late bolting trait in radish.