• KOREAN JOURNAL OF CROP SCIENCE
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• v.22 no.1
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• pp.110-134
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• 1977

Effects of phosphorus, potassium and calcium applications on root activity and agronomic characters of paddy rice were studied in submerged paddy soil on which starch was applied to accelerate soil reduction and production of toxic substance during 1971～1973. Root activity at heading date was decreased in reduction accelerated soil by starch application. Effect of calcium application on root activity was differed along soil conditions, phosphorus or potassium levels. Single effects of phosphorus or potassium application were not significant on every observed characters. Calcium application when phosphorus or potassium was not used as basal but used as top dressing increased yield and yield components, especially filled grain ratio. Effect of calcium application along soil conditions was differed on agronomic characters, but calcium application with phosphorus or potassium was more effective to increase yield components and grain yield. Sufficient application of phosphorus, potassium and calcium could improve the nutritional situation of rice plant for panicle development and grain maturity in reduction accelerated paddy soil in which poor growing of rice plant after panicle formation is anticipated by the production of toxic substance from soil.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.68 no.4
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• pp.225-235
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• 2023

Critical temperature for grain filling of three Korean japonica rice varieties was analyzed by late transplantation to induce a low temperature during grain filling period in a field study. The grain filling percentage (GFP) and grain dry weight (GDW) showed a sigmoid development for the first and second transplants in 2020 and first to third transplants in 2021. For the third transplant in 2020 and fourth transplant in 2021, the GFP and GDW reached a peak at 42 days after heading (DAH), and then decreased or remained unchanged. In non-linear regression analyses, 95% of the final GFP and GDW appeared at 49 - 62 DAH for the second transplant in 2020 and at 37 - 46 DAH and 30 - 36 DAH for the second and third transplants in 2021, respectively. At these time points, the critical seven-day moving temperature (7dMovT) was 8.4~9.4℃ for the second transplant in 2020 and 9.4~10.9℃ for the second and third transplants in 2021, depending on the grain filling traits and varieties of rice. The lowest 7dMovT was 8.4 - 8.7℃ in the three varieties. The observed lowest 7-day mean temperature (7dMT) accompanying increases in the GFP and GDW was 9.4 - 10.1℃, depending on the varieties in the third transplant of 2020 and fourth transplant of 2021. In the two transplants mentioned above, the highest 7dMT that showed no increase or decrease in grain filling traits was 8.7 - 9.1℃. The critical temperature for grain filling of japonica rice was 8.4 - 8.7℃ based on the 7dMovT and 9.1 - 9.4℃ based on the 7dMT. The previous 7dMT of 10℃ is recommended to determine the marginal harvest time for safe rice cropping since the temperature was the highest among the lowest temperature that accompanied an increase in grain filling traits.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.29 no.4
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• pp.334-341
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• 1984

Yield response of 30 rice varieties widely grown during the past 70 years in Korea was examined at the six transplanting dates from May 10 to June 29 at the 10 day intervals in 1982. Early japonica varieties grown before 1960s showed the highest yield at the June 9 and 19 transplantings and yields decreased with earlier or later transplantings except the earliest transplanting of May 10. However, yield of recent japonica varieties grown after 1960s was similar among the transplanting dates from May 10 to June 19, but yield was lower at the June 29 transplanting. In the indica/japonica varieties grown after mid- 1970s, yield was highest at the May 10, 20, and 30 transplantings and it decreased with further delay of transplantings largely due to the decreased panicle number, percent ripened grains, and 1,000 grain weight. This may indicate that recently developed varieties may be more adaptable toearly transplanting than older varieties. The number of panicles per hill was variable among the transplanting dates in all varieties, but it decreased as transplanting dates delayed after June 9. In japonica varieties the number of spikelets per panicle, percent ripened grains, and 1,000 grain weight increased as transplanting was delayed. However, in indica/japonica varieties the number of spikelets per panicle was similar among the transplanting dates and percent ripened grains and 1,000 grain weight decreased as transplanting date was delayed after June 9. The percent ripened grains of japonica varieties decreased with increase in the number of spikelets per hill but increased as heading date delayed. However, in indica/japonica varieties the percent ripened grains was not affected by both the number of spikelets per hill and heading date except that of June 29 transplanting of which percent ripened grains was extremely low because of delayed heading although the number of spikelets per hill was low. Grain/Straw ratio was not affected by heading date in japonica varieties, but it decreased significantly as heading date was delayed in indica/japonica varieties.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.15
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• pp.99-113
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• 1974

This experiment was carried out to find reasonable semi. hot seedbed system for early transplanting of "Tongil"rice cultivar. The quality of the young rice-plants, yield, and the occurrence of the reddish dry leaves were not significant differences between the seedbed with polyethylene tunnel and that of Rat covering. The per cent of healthy seedling of the soil preparation with the dry soil plowing was increased than that of the water soil plowing. The stability of the seedling cultivation of the thin layer straw mulching seedbed beneath the polyethylene film was higher than that of the common flat seedbed system.ed system.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.5
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• pp.662-669
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• 1995

To clarify the effect of temperature during ripening on grain quality, rice plant which was grown under normal natural conditions untill heading stage was subjected various temperature regimes during grain filling stage. Three varieties, Odaebyeo, Hwaseongbyeo and Dongjinbyeo were used. Grains on primary and secondary-rachis branches were harvested seperately and measured specific gravity, grain size and weight. The optimum daily temperature for grain filling of rice during ripening period was about 22$^{\circ}C$ and grain filling under alternating temperature(26/18$^{\circ}C$, day /night) was better than constant temperature (22 /22$^{\circ}C$) based on 1, 000-grain weight and yield. Grain size based on volume per grain was smallest under the constant temperature of 22 /22$^{\circ}C$. The size of secondary-rachis branches was smaller than primary-rachis branch. The difference in size between primary and secondary-rachis branches was biggest in Hwaseongbyeo, followed by Odaebyeo and Dongjinbyeo. The temperature regimes treated did not influence the grain size difference between branches so much. The 1000-grain weight was lighter under high temperature than low temperature in Odaebyeo, but reversed tendency was observed in Dongjinbyeo of secondary rachis-branches.

• Korean Journal of Agricultural and Forest Meteorology
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• v.2 no.4
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• pp.148-155
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• 2000

The typhoon and flooding injury in rice were investigated both the region of downpour at the middle of August and the region of typhoon 'Yanni' at the late of September, 1998 in Kyongbuk provincial of Korea. More than 10% of rice stem were buried by soil inundation, the heading was delayed and the high node tiller was brought out. Yield components were deteriorated and yield was reduced. As the clay in the muddy water was attached on grains of rice, the yield was greatly reduced by reason of low grain filling ratio and polished rice ratio. The injury of muddy water was less at yellow ripening stage than at early ripening stage. On the other hand, the muddy water injury was reduced by the fungicide 'Benomyl' and 'Daconil' treatments. The degree of lodging according to varieties and ripening stages was not made a great difference, while the lodging was mainly occurred in the early transplanting time. In a week after lodging, viviparous spikes were occurred in almost all varieties, the degree of viviparity was shown highly in order of early maturing, middle maturing and late maturing varieties in the field as well as in laboratory test. The viviperous spikes were greatly occurred in the lodging toward hill space within row than row space because the more grains were touched on the ground.

• Proceedings of the Korean Society of Organic Agriculture Conference
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• 2009.12a
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• pp.283-283
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• 2009

본 연구에서는 2008년 전라남도 나주시 반남지역과 노안지역 두 곳의 벼 농가포장에서 유기재배 및 관행(일반)재배 시험을 수행하고 벼 병충해발생, 생육 및 수량, 그리고 쌀의 품위 및 품질을 비교 분석하였다. 시험의 연구결과를 요약하면 다음과 같다. 1) 벼 병충해 방제는 노안지역 관행재배는 2회, 반남지역 관행재배는 4회 실시하였으며 유기재배는 노안, 반남지역 모두 2회 실시하였다. 포장에서 벼 병해충은 줄무늬잎마름병, 잎도열병, 이삭도열병, 잎집무늬마름병, 흰잎마름병, 혹명나방, 멸구류가 주로 발생하였다. 벼 병해충 중 잎도열병, 이삭도열병, 혹명나방은 관행재배보다 유기재배에서 발생이 많았다. 2) 벼생육상황은 간장이나 수장은 관행재배에 비해 유기재배에서 약간 짧은 경향이었다. 노안지역은 유기재배의 경우 관행재배에 비해 주당수수는 0.6개 정도 많았으나 수당입수, 등숙비율, 정현비율, 현미 천립중이 낮았다. 반면 반남지역은 유기재배의 경우 관행재배에 비해 주당수수는 0.8개 정도 적었으나 수당입수와 등숙비율은 높았고 정현비율은 낮았다. 전체 수량은 유기재배가 관행재배에 비해 노안지역은 84% 수준이고, 반남지역은 94% 수준이었다. 3) 쌀의 품위는 노안지역과 반남지역 두 지역 모두 완전립율이 관행 재배보다 유기재배에서 낮은 경향을 보였다. 쌀의 품질은 반남지역의 경우 유기재배시 기비로 사용한 질소가 관행재배에 비해 많아서 늦게 비효가 발현되어 이삭도열병, 혹명나방 피해가 발생하여 관행재배에 비해 단백질, 취반미 윤기치값이 낮았다. 반면 노안지역의 경우 유기재배시 기비로 사용한 질소가 관행재배에 비해 적어서 관행재배보다 단백질, 백도, 취반미 윤기치 값 등에서 양호하게 나타났다. 이상의 연구 결과를 소비자들에게 홍보하여 이들로부터 소비를 촉진케 함으로써 벼 유기재배 농가의 소득증대에 기어코자 한다.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.30 no.1
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• pp.26-32
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• 1985

Ten recommended rice varieties were cultivated in paddy area affected by air-pollutants and in normal area to select varieties adaptable to air-pollution environment. Rice plants grown in pollution site showed higher contents of total sulfur and fluorine in leaf through the whole growing period compared with those in non-pollution site, and rice leaves destroyed by air-pollutants were found only in pollution site. Rice grain yield and four yield components of ten rice varieties grown in pollution site were lower than those in normal area. Five rice varieties among ten were selected as adaptable to air-pollution environment, based on their yielding potential in pollution site and grain yield ratio between two sites. Rice varieties adaptable to pollution showed little variation of percent ripened grains and number of panicles per hill between two sites. Chlorophyll content in flag leaf of rice plants grown in pollution area was lower than in non-pollution area. No relationship was found between grain yield ratio (pollution/non-pollution site) of ten varieties and total sulfur content ratio, fluorine content ratio, chlorophyll content ratio between two sites, and percent destroyed leaf in pollution site, respectively. This result suggest that varietal adaptability to air-pollution environment is not related with the amount of pollutants absorbed, but with the degree of response to pollutants.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.19
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• pp.25-31
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• 1975

In order to increase the rate of ripening during the grain-forming stage the partial dressing was introduced with the ordinary dressing comparatively. Two different rice varieties, Bong-kwang(early) and Nong-kwang (moderate), grown at the fine sand alluvial soil of River, Han Kimpo, were investigated. To evaluate the photosynthetic ability of these treatments assimilation rate of Carbon-14 was effectively carried out with the active leaves of rice at the maturing stage, and the inorganic constituents of leaves, stem, leaf sheath and grain were analyzed. All the data on the photosynthetic ability, inorganic constituent and yield determining were discussed with the point of continual phloem translocation between those plant organs.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.36 no.1
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• pp.34-40
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• 1991

The study aimed to investigate the relationship between the rates of leaf senescence and photosynthate translocation at post-anthesis. Seven barley varieties were observed at Suweon in 1988-89. The varieties differed significantly in the number of leaves survived and the rate of photosynthate transolcation with the progress of grain filling. The rate of grain filling was higher in the fast leaf sene-scencing varieties than the slow senescencing ones. There was a close coincidence between the rates of grain filling and $\^$14/c translocation into grains. Photosynthesis was higher in the fast leaf senescencing varieties at early stage of grain filling, but the reverse phenomenon was observed at the late stage of grain filling. The grain yield of fast senescencing varieties was higher than that of slow ones.