• Journal of the Korean Society of International Agriculture
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• v.23 no.5
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• pp.520-530
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• 2011

This study was carried out to evaluate the possibility of rice double cropping in Korea by assessing the growth and yield performance of rice cultivars transplanted at the extremely-early date. When the transplanted rice seedling was exposed to low temperature below 0℃, the survival rate decreased drastically. However, short exposure to below 0℃ one or two times did not damage transplanted rice seedling so severely. Thus, the earliest transplanting in spring would be possible when minimum temperature rises above 0℃. Compared with the conventional seedling nursery tray (CSNT), seedling rearing with the potted nursery tray was more effective for increasing leaf age and seedling dry weight during nursery period. In the first rice cropping, rice cultivation with seedlings reared in PSNT showed shorter growth duration and cumulative temperature from transplanting to heading than that with seedlings reared in CSNT. The earliest heading date on July 4 in Jinbuolbyeo was earlier by two to three days than that of Dunaebyeo. If rice has not exposed to cold damage, the earliest heading date of Jinbujolbyeo can advance to June 30 or July 1. In this case, rice harvest would be possible on August 5, enabling the rice transplanting of the second rice cropping before August 10. At transplanting time with low temperature damage rice yield were less than 400 kg/10a while rice yield exceeded 400 kg/10a at transplanting time without low temperature damage.

• BMB Reports
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• v.30 no.4
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• pp.292-295
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• 1997

Exposure of seedling of rice (Oriza sativa cv.Dongin) to cold stress ($6^{circ}C$, 7day) induced differential gene expression. Differentially expressed polyadenylated RNA induced by low temperature were isolated and identified from the leaves of rice (Oriza sativa cv.Dongin) seedling by using the technique, differential display of reverse transcription through polymerase chain reaction (DDRT-PCR). Four bands of cDNAs were differentially displayed on the PAGE gel through DDRT-PCR, and among them three bands were those of overexpressed genes while one band was of an underexpressed gene One of the overexpressed cDNA was characterized. The size of the DDRT-PCR product was found to be about 200 bp. The sequence of the cloned DNA was compared with those of GenBank through a BLAST E-Mail server, and it was found to have no homologies in the nucleotide sequence with that of any known DNA: therefore, it was designated as RC101 The expression of the cold-stress induced-gene, RC101, was sustained with Northern Blot analysis by using the cloned DDRT-PCR product as a probe.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.3
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• pp.295-301
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• 1996

This study was carried out to clarify the effect of sprout length, burried depth of seed and CaO$_2$ seed coating on emergence, seedling stand and early growth of rice in puddled-soil drill seeding at Junbuk in 1995. The cultivar tested was Dongjinbyeo(Japonica type). Although the longer sprouted seeds were caused the better seedling stand, 4mm sprout length of seeds appeared to be appropriate for good seedling stand and seeding uniformity, while 6mm sprouted seed resulted in ununiform seedling establishment. Rapid emergence and increased seedling stand were obtained by CaO$_2$ seed coating, which had effect more on soaked seed than on sprouted seed, but the seedling stand of sprouted seeds significantly reduced at deeper than 1cm seeding depth and also emergence rate of sprouted seeds significantly reduced at deeper than 2cm seeding depth.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.57 no.4
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• pp.441-448
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• 2012

This study was carried out to evaluate the productivity of rice cultivation in extremely late season in Korea and to confirm the effects of pot-raising seedling culture in this case by assessing the growth and yield performance of rice cultivars that are well adapted to late culture. Suitable cultivars for extremely late culture should not have premature heading habit when transplanted around late July and also secure appropriate growth duration before heading. Geumobyeo 1 and Manjongbyeo showed small decrease in the emerged leaves in transplanting in late July or early August and heading occurred at the same time relatively without premature heading. At transplanting from late July to early August in extremely late rice cultivation, ripening was relatively good until transplanting on August 5. At transplanting on July 30, accumulated temperature from heading to the first frost was $853^{\circ}C$ and ripening was good enough. However, heading was delayed by low temperature at transplanting on August 10 and ripening was very poor due to low accumulated temperature of below $800^{\circ}C$, causing drastic decrease of rice yield. The rice yield increased in transplanting with pot seedling, especially the effects of pot seedling was higher in Geumobyeo 1, but panicle number was not enough to secure rice yield owing to short growth duration. In order to cultivate rice in extremely late season, we should select adaptive rice cultivars that have suitable growth duration and excellent ripening in low temperature. Here, pot-seedling did a great role to secure early growth and bigger growth amounts.

• Korean Journal of Organic Agriculture
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• v.19 no.spc
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• pp.92-95
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• 2011

The initial investment of rice cultivation by mechanical technique was high. This was only due to the cost of planting machine. We analysed the overall cost (without machine cost) and benefits of the two methods, it manifested that the mechanical method is very much beneficial over traditional rice cultivation technique. We observed that the requirement of soil, irrigation water, number of seeds etc. decreased in mechanical cultivation technique while net income increase by 13.07% with 80% government subsidy. Furthermore, the initial rooting was quicker, growth and development of pot raised seedlings was better than the traditional technique. Hence, this technique can give better return to the farmers with the help of government subsidy.

• Korean Journal of Weed Science
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• v.14 no.2
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• pp.101-106
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• 1994

Factors affecting phytotoxicity of dithiopyr in rice such as transplanting depth, seedling age, soil texure were examined and mechanism of phytotoxicity in rice was also determined by absorption study of $^{14}C$-dithiopyr in rice seedlings under above conditions. Rice injury was occurred in shallow transplanting depth, young rice seedlings and sandy soil conditions. Higher amount of dithiopyr was absorbed in rice at shallow transplanting depth and sandy soil conditions which may related to phytotoxicity of dithiopyr.

• Korean Journal of Soil Science and Fertilizer
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• v.23 no.1
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• pp.34-39
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• 1990

The experiment was conducted in the pots of flooded saline paddy soil to evaluate influence of rice straw and gypsum application on germination and early growth status of directly sowed rice seedlings. 1. Germination percentage of rice seedlings were higher in treatment sowing at 1 day after submergence than that of treatment sowing at 21 days after submergence, and was severely interrupted by rice straw application. 2. Application of rice straw promoted the release of bicarbonate and volatile fatty acid of submerged water, while the amount of sulfate and soluble cations were decreased as compared to control. 3. Germination percentage of rice seedling had significant negative correlations with chemical characters of submerged water, and was highly affected by submerged water at 7 days after sowing. 4. Rice straw application interrupted germination of rice seedling by increasing pH of submerged water over critical level, and gypsum application depressed the early growth of young seedling dues to high salt concentration. 5. The relaease of bicarbonate was remarkedly increased with increasing pH over 7.5 of submerged water.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.57 no.4
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• pp.456-462
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• 2012

In the new changing scenario, the goal of agriculture is shifting from traditional to sustainable and environment-friendly agriculture. Therefore, in this experiment, we analyzed economic efficiency of two methods of rice cultivation i.e. new cultural method and conventional method, at farmers' fields. In the new cultural method, cost of materials and machines (rice-transplanting and sowing machine) was found 245% higher than the conventional method. Depreciation of cost and working hours were also higher in the new cultural method by 1.9 and 1.1 time, respectively. However, cost of seeds and seedbed soil were 44.0% and 49.2% lower and total material cost was 4.4% lower than the conventional method. In the new cultural method, overall working cost of nursery raising and transplanting per 10a was 229.8% higher than the conventional method. However, in spite of high input cost, yield of rice in new cultural method was higher by 6.7% than the conventional method. Our results showed that new cultural method was better than the conventional method except the input cost. If government provide 80% subsidy for machine cost then its input cost will be reduced by 45.4% than the conventional method.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.12
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• pp.55-62
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• 1972

In order to study the biolgiocal effects of dry back following EMS (Ethyl methane sulfonate) treatment on seeds of 'Dunghan Shali' that belongs to indica-type rice with various presoaking(24, 36, and 40 hrs respectivily) and treatment time(l, 2 and 3 hrs respectivily), this experiment was done. Seedling heights of wet seeds presoaked for 36 hrs was only greatly decreased with EMS treatment compared with other periods. In germination rate of wet seeds, all of these damage was not changed. For the drying back seeds, otherwise, seedling height and germination rate were greatly reduced depend upon the time of treatment and presoaking as well as storage effects after drying back. Reduction patterns, both seedling height and germination rate, between 1 week and 8 weeks after dry back were quite similar. The other experiment was carried out in order to study for the influences on the seedling growth as biological damage with EMS and MMS(Methyl methane sulfonate) treatments among different varieties. The indica-type rice varieties; Taichung Native No.1, Dunghan Shali and IR-8, were used as the experimental materials. From this trial some results were obtained as follows; 1. Both seedling growth and germination rate on all varieties, used, MMS, treatment showed more toxic effects than those of EMS treatment. 2. Seeding growth injury of rice seeds dried back was increased gradually, and then was approached the maximum at 6-8 days after storing. In IR-s variety, otherwise, growth damage was appeared a little. Germination rate of these were quite smilar, even though chemical used is different and storage period was prolonged. 3. It was showed clearly that varietal differences of chemical mutagene treatments were recognized.

• Proceedings of the Korean Society of Crop Science Conference
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• 2001.09a
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• pp.102-103
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• 2001