• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.spc1
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• pp.51-55
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• 2005

The characters associated with the quality of rice and the factors involved in the production of high quality rice as the proper transplanting time was examined at Unbong the southern alpine area from 2002 to 2004. The rice cultivars tested were Samcheonbyeo (Early maturing one), Sangmibyeo (Sub-early maturing one). The number of spikelets were increased as earlier the transplanting date in all cultivar, The ripened grain rates were highest transplanted on May 21 for Samcheonbyeo, and May 1 for Sangmibyeo. The highest head rice yield was obtained when transplanted on May 21 and May 1 for Samcheonbyeo and Sangmibyeo, respectively. The optimum transplanting dates according to maturing types with respect to the yield of head rice, ripened grain rates and rice quality were May 21 for early maturing type and May 1 for sub-early maturing type.

• Journal of agriculture & life science
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• v.53 no.2
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• pp.87-95
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• 2019

This study was carried out to select the rice variety for high quality rice according to reducing N application level (7 kg/10 a) in medium altitude and plain of southern Korea. It was cultivated to seven varieties and ten varieties in medium altitude and plain region respectively in this study. In medium altitude region, the yield of head rice was higher in most varieties except for Borami (526 kg/10 a) than the control variety, Chucheongbyeo (533 kg/10 a). On the other hand, Borami, Gopumbyeo, and onnuri were lower in head rice rate than the other varieties. In addition, Borami and Chucheongbyeo shown a lodging risk but the other varieties were safe against lodging. The milled rice protein content of Chucheongbyeo was 6.1% and the other varieties protein content was similar or lower than that of control except for Borami(6.3%). In plain region, the head rice yield of Nampyeongbyeo (527 kg/10 a) was higher than that of control variety, Ilmibyeo (503 kg/10 a). Head rice rate was lower in Hopumbyoe, Sindongjin, and Chilbobyeo than the other varieties. The varieties contained lower protein content compared Ilmibyeo (6.1%) were Hopumbyeo (5.9%), Jinsumi (6.0%), Sindongjin (5.9%), Chilbobyeo (6.0%), Hwangeumnodeul (5.8%), Hopyeongbyeo (6.0%). Amylose content, whiteness, and palatability (Toyo value) were no significant difference among varieties in two different regions. In conclusion, considering head rice rate, yield of head rice, protein content, lodging resistance, ripening rate and palatability, Pungmi1ho, Saenuri, Chilbobyeo in medium altitude region and Jinsumi, Hwanggumnodul in plain region were selected as proper rice varieties for high quality rice production in southern Korea.

• Journal of Biosystems Engineering
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• v.32 no.5
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• pp.332-338
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• 2007

Yield mapping is necessary for precision farming. An on-site rice weighing system for a head-feed combine was developed to measure the total weight of rice grain harvested while the combine was operated. A load cell system was used to monitor rice weights accumulated into the combine grain tank using a load cell. This method gave cumulative grain weight readings as a function of time. The system consisted of a load cell, two supporting brackets, and a computer-based data acquisition system. The weights measured with the system from two fields were compared with those obtained with a commercially available electronic balance. The response of the load cell to varying grain weights was linearly modeled, showing a coefficient of determination of 0.998 and a standard error of ${\pm}4.09kg$.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.123-123
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• 2022

In order to evaluate the effect of nitrogen application levels on yield and protein content of rice varieties, a field experiment was conducted at National Institute of Crop Science of Korea in 2020. Five levels(0, 3, 5, 7, and 9 kg·10a^-1) of nitrogen fertilizer were treated to six Korean rice varieties. The nitrogen uptake amount, soil nitrogen content before and after rice cultivation, milled rice yield, and protein content in head rice were analyzed. As the treatment of nitrogen fertilizer increased, the nitrogen uptake amount of plants increased significantly. However, changes in nitrogen content in the soil before and after rice cultivation were different for each cultivar. The amount of nitrogen change in the soil decreased as the amount of nitrogen application increased in the three cultivars of Haepum, Gopum, and Odae, and the other three cultivars showed the opposite trend. As a result of correlation analysis of nitrogen application amount, nitrogen uptake amount, milled rice yield, and protein content of head rice, the five varieties except for Haepum showed a high correlation between these factors. The amount of nitrogen application and nitrogen uptake of plant showed a positive correlation about the milled rice yield and protein content of head rice. In particular, the protein content in head rice appeared to be more affected by nitrogen uptake amount than nitrogen application amount. As a result of this study, the yield and protein content of rice had positive correlations with the level of nitrogen fertilizer, and had a high correlation with the nitrogen absorption of plants.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.spc
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• pp.1-8
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• 2008

We carried out this study to analyze changes of rice grain milling properties according to the transplanting time and to identify genetic resources suitable for improving milling quality of rice in paddy field of Yeongnam area. We analyzed grain filling and milling quality of 30 rice varieties. In late transplanting (June 20), heading date was delayed for 6 days, compared to normal transplanting(June 5). The grain filling ratio (GFR), perfect kernel ratio of milled rice (PKR), and head rice recovery (HRR) were improved in late transplanting. There was no significant difference in head rice yield of two transplanting time, even though the milled rice yield in late transplanting was significantly smaller than that in normal transplanting because of the reduction of spikelet numbers per panicle. The uniformity of brown rice grain measured by selection sieve norm was improve in late transplanting. There was no significant difference of milling loss ratio between normal and late transplanting but there was a trend for a increase of milling necessary time in late transplanting. Thus, our result suggest that optimum transplanting time is June 10 to 15 to improve grain filling and milling quality and produce high head rice yield in the southern paddy plain of Yeongnam region. We selected promising 9 rice varieties which are Nampyeongbyeo, Ilmibyeo, Chucheongbyeo, Dongjinbyeo, Hopyeongbyeo, Malguemi, Chilbo, Hinohikari, and Cheongmu having high percentage of ripened grain and milling quality as genetic resources to improve milling characteristics of rice varieties. Chucheongbyeo, Dongjinbyeo, and Malguemi showed the highest grain filling ratio and Nampyeongbyeo had the highest perfect kernel ratio. Nampyeongbyeo and Ilmibyeo showed the highest head rice yield with more than 500 kg/10a.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.spc1
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• pp.30-34
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• 2006

The effect of N-fertilization on yield, milling characteristics and quality of Samcheonbyeo, an early maturing rice variety, was investigated in 2002 to 2004. The study was carried out in the southern alpine area of Un-bong Sub-Station, Honam Agricultural Research Institute. Higher nitrogen levels increased number of panicle and grain per unit area, but lowed ripening rate and decreased 1,000-grain weight. Higher nitrogen levels of up to 90 kg/ha also increased head rice yield. A nitrogen level of 90 kg/ha was found optimal for increasing ripening rate and head rice yield, and rice palatability.

• Mycobiology
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• v.46 no.3
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• pp.283-286
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• 2018

Fusarium graminearum causes the devastating plant disease Fusarium head blight and produces mycotoxins on small cultivated grains. To investigate the timeframe of F. graminearum infection during rice cultivation, a spore suspension of F. graminearum was applied to the rice cultivars Dongjin 1 and Nampyeongbyeo before and after the heading stage. The disease incidence rate was the highest (50%) directly after heading, when the greatest number of flowers were present, while only 10% of the rice infected 30 days after heading showed symptoms. To understand the mechanism of infection, an F. graminearum strain expressing green fluorescent protein (GFP) was inoculated, and the resulting infections were visually examined. Spores were found in all areas between the glume and inner seed, with the largest amount of GFP detected in the aleurone layer. When the inner part of the rice seed was infected, the pathogen was mainly observed in the embryo. These results suggest that F. graminearum migrates from the anthers to the ovaries and into the seeds during the flowering stage of rice. This study will contribute to uncovering the infection process of this pathogen in rice.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.59-59
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• 2022

The transplanting date of rice affects grain yield and quality, and it is changed by the environment during cultivation. Thus, it is important to provide the optimal transplanting dates for rice growers under global warming environment. In this study, transplanting date experiments with thirty-day-old seedlings of three cultivars (early, mid, and mid-late maturity) were conducted at the National Institute of Crop Science in Suwon from 2018 to 2021 to determine the optimal transplanting dates for and quantify the effect of planting dates on yield and quality. Transplanting date was strongly associated with culitvar across every year. Clear relationships between transplanting date and head rice yield in early and mid-late maturing rice varieties were observed, and the highest head rice yields were observed during transplantings in mid and late June for early maturing cultivar and mid June for mid-late maturing cultivar. It is obvious that the optimal rice transplanting dates have been shifted and are better later than the optimal transplanting dates in 2002-2004. Days to heading was also strongly associated with the transplanting date and cultivar with 89% of the variation explained. Days to heading was reduced in the later transplanting dates. Grain yield was strongly associate with biomass production during ripening(R²=0.85), however translocated biomass from leaf and stem showed little association with grain yield. The results from this study reconfirmed the importance of shifting optimal transplanting dates to maximize head rice yield for the Mid-plain area in South Korea.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.261-261
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• 2017

This study was carried out to provide basic data for spreading rice direct seeding by inducing stabilization of seedlings, yield and quality according to sowing times in rice direct seeding cultivation. In 2016, 'Sukwang' was seeded 3 times by 10 days interval on May. 10, 20, 30 and 6kg/10ha of seeding rate respectively in Iksan. In summary, the number of rice seedling establishment was higher than the optimum seedling establishment level at all sowing periods and the seeding rate was better as the sowing period was delayed. Weed development by sowing was the highest at early sowing, May 10, and decreased at late sowing. Heading dates were delayed by 3days for sowing on May 10, 7days for sowing on May 20, and 11 days on sowing on May 30. Rice yield increased with the delay sowing time and compared to the transplanting. It was 84% in sowing on May 10, 94% in sowing on May 20, and 99% in sowing on May 30. In addition, head rice ratio and head rice yield increased according to delayed of seedling.

• Korean Journal of Agricultural Science
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• v.42 no.3
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• pp.151-158
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• 2015

This study was conducted to know the variation and relationship of rice grain quality and starch pasting properties by transplanting times. Two early maturing rice cultivars which accounted for the most area of early maturing rice cultivar in Chungnam province were used. The experiment was laid out in a split-plot design with 3 replications. The main plot consisted of three transplanting times viz. early (April 25), ordinary (May 25) and late (June 25) with sub-plots containing two cultivars. According to the transplanting times, most of rice grain quality and starch pasting properties showed significant difference and Joami showed higher grain quality than Unkwang in all transplanting times. Especially, rice grain quality was improved when transplanted late, showing high head rice and glossiness of cooked rice due to the lower mean temperature during grain filling stage. Glossiness of cooked rice was positively correlated with head rice ratio, amylose content and setback value, and negatively correlated with chalky rice ratio and protein content. The highest positive and negative correlation were observed between breakdown value and peak viscosity ($r=0.98^{**}$), and breakdown and setback ($r=-0.94^{**}$), respectively. These results provide some information for rice researchers and producers producing cultivars with an improved quality, suggesting that rice quality is highly influenced by temperature at grain filling stage, and transplanting times is crucial in improving rice quality. In addition, starch pasting properties are useful for determining rice quality because rice grain quality and starch pasting properties are dependent on each other.