• Korean Journal of Environmental Agriculture
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• v.14 no.2
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• pp.246-249
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• 1995

This study was conducted to establish the optimal ratio of $NO_3^-$ and $NH_4^+$ for the nutrient culture of Gerbera hybrida Hort. The results were summarized as follows; 1. The growth of 'Volga' was best in 8 : 2($NO_3^-$ : $NH_4^+$) solution, while that of 'Mirage' was in 9 : 1 ratio. 2. The maximum quantity of cut flowers could be harvested in the 8 : 2 solution in 'Volga', whereas in 9: 1 solution in 'Mirage', but the differences between 9 : 1 and 8 : 2 were not significantly great. 3. In 'Volga', the qualities of cut flowers were not different among 10 : 0, 9 : 1 and 8 : 2, while those in 'Mirage' were not different among all treatments. 4. It turned out that the optimum ratio of $NO_3^-$ and $NH_4^+$ for the nutrient culture of gerbera in the farm house was 8 : 2, irrespective of cultivas.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.25 no.4
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• pp.1-9
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• 1980

To determine the optimum harvest time of recent rice varieties from Indica/Japonica remote crosses, leading varieties Suweon 264 and Milyang 23 were tested for the changes in dry matter weight and moisture content of grain, shattering, shelling ratio, milling ratio, and apparant physical quality during grain development at 5 day-intervals from 20 days to 55 days after heading. The results are summarized as follows: 1. Grain weight (dry matter) reached its maximum (physiological maturity) at 30 days after flowering (DAF) in Suweon 264, and at 35 days in Milyang 23, and thereafter it did not change significantly until 55 DAF. 2. Time course of decrease in grain moisture content (Y, %) during maturation (X, DAF) consisted of two linear phases, i.e. a fast and a slow period: Y=68.245-1.33X until 34DAF, and Y=23.025-0.470X until 55DAF after 34DAF in Suweon 264; Y=73.62-1.634X until 24.5DAF, and Y=33.59-0.570X until 55DAF after 24.5DAF in Milyang 23. Two varieties showed the same grain moisture content of 28% (wet basis) at physiological maturity in spite of the distinct differences in the heading date, time of physiological maturity and thereby ripening climate. 3. Force to shatter a grain ranged about 90 to 100g in Milyang 23, and about 200 to 250g in Suweon 264 and in a Japonica variety, Jinheung. The force, however, did not change significantly with harvest time from 35DAF to 50DAF. 4. The changes in the ratios of shelling, milling, broken rice and tinted rice with harvest time were insignificant during a period from 35DAF to 55DAF. However, ratios of green rice and white belly rice decreased significantly with delay in harvest time during 10 days after physiological maturity. 5. The best time of harvest for maximum yield and good quality is thought to be 10 days after physiological maturity, and grain moisture content at this time was about 20% on wet basis.

• Horticultural Science & Technology
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• v.19 no.3
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• pp.362-366
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• 2001

This survey was carried out to investigate the effect of flooding by heavy rain on growth characteristics and disease incidence of 'Fuji'/M.26 mature apple tree in 1998 at Kyongbuk province. The surveyed regions were Andong, Uisung, and Gunwi area. The six orchards were selected from one area, totally 18 orchards were surveyed. The flooded depth of surveyed orchards was from 70 to 350 cm, and the flooded duration was from 6 to 72 h. Defoliation ratio, number of abnormal budding, and flowering per tree were increased along with the increment of flooded depth and duration. Rooting ratio was decreased rapidly with the increment of flooded duration, and dead root ratio was 16.2% in flooded orchards. Marssonia blotch (Diplocarpon mali), white rot (Botryosphaeria dothidea) of fruit, and phytophthora fruit rot (Phytophthora cactorum) incidence were increased in flooded orchards. The analysis results of pearson correlation coefficient among surveyed items showed that higher relationship of abnormal growth characteristics and increment of disease incidence of 'Fuji'/M.26 apple trees with flooded duration than with flooded depth. With these results, the flooded depth was found to be the main factor for the abnormal growth characteristics and disease incidences of 'Fuji'/M.26 apple trees.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.6
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• pp.647-651
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• 1997

Flowering date of peanut variety, Daekwangtangkong and Daepungtangkong in non-mulching culture was delayed each 9 and 6 days. Seedling ratio was decreased each 3.7%, 16% and branch length was decreased each 24%, 17% more than polyethylene film mulching culture. But the number of branch in non-mulching culture was not reduced. No. of mature pods, kernel/pod ratio, 100-seed weight and kernel weight per plant was reduced extremely in non-mulching culture, nevertheless the kernel yield per 1 ha of Daekwangtangkong in non-mulching culture was similar to that of polyethylene film mulching culture but yield of Daepungtangkong was 26% higher than that of polyethylene film mulching culture owing to planting density. Protein content of Daekwangtangkong in non-mulching culture was increased 4% but that of Daepungtangkong was decreased 3% and oil content of both variety was decreased 7%, 9% respectively comparing to polyethylene film mulching culture. Oleic acid was increased but linoleic acid was decreased and O/L ratio was decreased in non-mulching culture.

• Journal of Korean Society of Forest Science
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• v.47 no.1
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• pp.16-26
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• 1980

Soluble carbohydrates and free amino acids in the terminal buds of Pinus elliottii were analyzed to understand the nutritional status of the buds during the period of female strobilus initiation. Grafted, 18-year-old slash pine trees in a seed orchard were divided into two groups, abundant-flowering (AFG) and poor-flowering group (PFG) according to their flowering history. Four types of terminal buds, with two types from each group, were examined: (1) large buds in upper crown (female-producing buds) and small buds in lower crown (male-producing) in AFG, (2) large buds in upper crown (vegetative buds) and small buds in lower crown (male-producing) in PFG. Bud samples were collected four times from late July to early September. Free sugars and free amino acids (75% ethanol-soluble) were determined by gas chromatography and automatic analysis, respectively. Sugar content in the large buds of both groups was greater than in the small buds of the same group. Fructose and glucose were major sugars found in the bud tissue. Arginine was the most abundant amino acid in all four types of buds, with the concentration increased from 23% in late July to 60% in early September. Arginine and total amino acid content in the female-producing buds of AFG was much lower than three other types of buds. When female-producing buds and male-producing buds of AFG were compared in their arginine content, the former contained about same amount as the latter in late July, but showed one-fourth of the latter in early September. The low level of argining in the female-producing buds suggested a minimal or negative role of arginine in the initiation of female flower primordia. A higher sugar to amino acid ratio was observed with female-producing buds of AFG than with vegetative or male-producing buds of either flowering group. The low amino acid content in the female­producing buds suggested that initiation of female strobilus primordia was associated with temporary reduction in the metabolic activity of the buds.

• The Korean Journal of Ecology
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• v.16 no.3
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• pp.329-339
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• 1993

Effects of relative light intensity and N, P fertilization on the growth and ramet dynamics of the rhizomatous plants, Arundinella hirta, Miscanthus sinensi and Spdiopogon sibiricus were studied in Chuncheon, Kangweon-Do. Ramets emerged in one pulse a year, withered in one pulse at the end of the growing season in M. sinensis and S. sibircus stands, while the birth and death pulse in A. hirta stands were two times. Total births of ramet were 9 times and 3.6 times greater in the unshaded fertilized stands of A. hirta and M. sinensis than in the shaded, However, those of S.sibiricus were 2.1 times greater in the shaded stands. Flowering rates of A. hirta, M.sinensis and S.sibiricus I the unshaded fertilized stands were 1.8, 2.7 and 1.04 times greater than in the shaded unfertilized stands, respectively. Height of ramets of A. hirta and M.sinensis were the hightest in the unshaded fertilized stands. However, that of s.sibiricus was the highest in the shaded fertilized stand. Aboveground production of A.hirta in the fertilized stand was 2.4 times greater in the unshaded stand than in the shaded one. Results of inflorescence frequency, shoot height and the ratio of aboveground to belowground were smiliar to the total births. The added fertilizer markedly increased the ramet density and the shoot productivity of three rhizomatous plants, especially of A. hirta.

• Korean Journal of Agricultural Science
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• v.44 no.1
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• pp.23-29
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• 2017

This study was conducted to explore which pollen type could be an effective pollen source for self-incompatible 'Niitaka' pear (Pyrus pyrifolia Nakai), when different pollinizers were to be applied. The pollens of five different pears with similar flowering times were applied to bagged 'Niitaka' flowers grown in Cheonan city, Korea. Pollen types used were of different origins including Korean pears ('Wonhwang' and 'Chuhwangbae'), Japanese pears ('Chojuuro' and 'Okusankichi'), and Chinese pear ('Yali'). Results show that the amount of pollen produced by flowers of each cultivar was the largest in Korean pear 'Wonhwang' (234 g/100 flowers) and the smallest in Japanese pear 'Okusankichi' (126 g/100 flowers). A high proportion of large fruits (> 600 g), 71.4% of total production, was found in the fruits treated with 'Yali' pollen. However, these fruits showed an unfavorable external appearance. Based on individual fruit width differences, 'Chojuuro' treatment produced the smallest difference in fruit diameters (3.2 mm) and 'Yali' treatment' gave the largest (4.8 mm). Also, the difference in fruit length was the largest in 'Yali' (7.5 mm), which also produced the most uneven fruits among the pollinizers used. Meanwhile, the use of pollens of 'Wonhwang' and 'Chuhwangbae' improved productivity by increasing the fruit shape index and the ratio of bigger fruits in total production. Moreover, those pollens also decreased the development of lenticels on fruit skins which gave them a smoother appearance.

• Korean Journal of Soil Science and Fertilizer
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• v.21 no.3
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• pp.272-279
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• 1988

A pot experiment was conducted to define the effect of various soil phosphorus fractions for soybean yield and the relations of between various soil phosphorus fraction and each other in 11 upland soils with different capacities of phosphorus fixation and physico-chemical properties of soils. The effect of phosphorus fertilization was high in soils with high capacities of phosphorus fixation and low available phosphorus, and soybean yield was showed significant relationship with available phosphorus and inorganic soil phosphorus fractions. Fractional recovery of added phosphorus in soils were showed various range of 2.5-91.7%, and mean value of soils was 48.5%. In the relationships among the soybean yield, plant phosphorus content, phosphorus uptake and available phosphorus, inoganic phosphorus at flowering stage, soybean yield were showed significant relationship with available phosphorus content, phosphorus uptake were all showed significant correlation without Fe-P, but Fe-P was showed except Jeju soil. Al-P/Fe-P ratio was increased by phosphorus fertilization in soils at flowering stage, and in the relationships between Al-P/Fe-P ratio and soybean yield, phosphorus uptake, soil and plant phosphorus were showed high significant correlation, but Fe-P was not showed at flowering stage. P sorbed by soils from P 20ppm solution was decreased by phosphorus fertilization, and then decreasing rate was higher in soils with low capacity of phosphorus fixation then high phosphorus fixing soils. Also P sorbed was showed negatively high significant correlation with available phosphorus, plant phosphorus, phosphorus uptake and soil inorganic phosphours except Fe-P, and soybean yield was not showed.

• Journal of the Korean Society of Tobacco Science
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• v.10 no.2
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• pp.109-116
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• 1988

Oriental tobacco (KA 101) was transplanted from Mar. 25 to May 5 with 10 days interval in 1984 and 1985, and its agronomic characteristics, chemical properties ware compared to determine the Proper transplanting time of aromatic tobacco In Korea. As the transplanting was delayed, days to flowering of plant was shortened, length and width of largest leaf, leaf area index tended to decrease. Yield was highest for the Apr. 5th transplanting followed by Mar. 25th planting, then decreased as the planting date was delayed. Quality by price decreased as the transplanting was delayed later than Apr. 25. Delaying transplanting increased nicotine, total nitrogen and ash content, but decreased reducing sugar and petroleum ether extract of cured leaves, The content of volatile organic acids such as 3-methyl pentanoic acid was lower when it was transplanted later than Apr. 25th. Neophytadiene content increased as the transplanting was delayed, but there were no trends with the content of alcohols, aldehydes esters and ketones. Several quality indices including the ratio between the content of volatile organic acids plus petroleum ether extract and ash content plus pH was higher for the Apr. 5th transplanting.

• Journal of the Korean Society of Tobacco Science
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• v.18 no.2
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• pp.132-137
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• 1996

This experiment was conducted to investigate varietal responses to cool temperature (18℃) and short photoperiod (8 hours a day) in a controlled room of phytotron. Five burley tobacco varieties (Nicotiana tabacum L.), Awelius (very early flowering type), Burley 21 and KB 103 (medium), Banket Al and MB 1 (slightly late) and TC 681 (late) were compared in number of leaves per plant and day to flower in different treatment periods (10, 15, 20, 25 and 30 days). The days to flower decreased significantly than the control (in the phytoron with 14hr photoperiods and a minimum temperature 20'c) when the treatment periods were over 15 days for the varieties Aurelius, Burley 21 and KB 103, and 20 days for TC 681, and 30 days for Banket Al, respectively. And also the number of leaves decreased significantly than that of the control when the periods of treatment were over 10 days for Burley 21 and Aurelius, 15 days form 103, and 20 days for TC 681 and Banket Al, and 30 days for MB 1, respectively. The decreasing ratio in the number of leaves per plant under cool temperature and short photoperiod treatments was the lowest in Banket Al and MB 1. Key words : Nicotiana tabacum, cool temperature, short photoperiod.