• KOREAN JOURNAL OF CROP SCIENCE
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• v.55 no.2
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• pp.98-104
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• 2010

Excess nitrogen (N) uptake of rice, which could cause much lodging, disease and reduction of rice quality, could be occurred at the paddy field with previous upland condition at which much soil N could be mineralized by soil-drying effect. N fertilizers of 0, 3, and 6 kg N $10a^{-1}$ were applied to early-maturity rice, cultivar Joanbyeo at the paddy field of first and second year after upland condition, and rice growth and nitrogen uptake were investigated to know the increase of rice N uptake at the paddy field with previous upland condition for one-year. Total dry matter (DM) and N uptake of rice at the paddy field with previous upland condition increased more than continuous paddy field. Total DM and N uptake of rice at the paddy field with previous upland condition increased linearly to N fertilizer 6 kg $10a^{-1}$ at the paddy field owing to vigorous growth compared to continuous paddy field. Rice N uptake was higher at the paddy field of the first year than the second year after upland condition in considering N uptake at the plot of no N fertilizer. Vigorous growth at the paddy field with previous upland condition resulted in higher rice yield which was related with high panicle and spikelet, but much N fertilizer as much as 6 kg $10a^{-1}$ at the paddy field with previous upland condition resulted in higher lodging and protein content of brown and milled rice. Particularly, protein content of brown and milled rice increased more when the same N fertilizer was applied two times splitly at transplanting and panicle initiation stage than when N fertilizer was applied one time at transplanting as basal N. N application with under 3 kg $10a^{-1}$ as only basal N was recommended at the paddy field with previous upland condition to obtain high quality rice without lodging.

• Korean Journal of Agricultural and Forest Meteorology
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• v.20 no.4
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• pp.296-304
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• 2018

The objective of this study was to analyze the impact of climate change on rice yield and quality. Experiments were conducted using SPAR(Soil-Plant-Atmosphere-Research) chambers, which was designed to create virtual future climate conditions, in the National Institute of Crop Science, Jeonju, Korea, in 2016. In the future climate conditions($+2.8^{\circ}C$ temp, 580 ppm $CO_2$) of year 2051~2060 according to RCP 8.5 scenario, elevated temperature and $CO_2$ accelerated the heading date by about five days than the present climate conditions, resulted in a high temperature environment during grain filling stage. Rice yield decreased sharply in the future climate conditions due to the high temperature induced poor ripening. And the spikelet numbers, ripening ratio, and 1000-grain weight of brown rice were significantly decreased compared to control. The rice grain quality was also decreased sharply, especially due to the increased immature grains. In the future climate conditions, expression of starch biosynthesis-related genes such as granule-bound starch synthase(GBSSI, GBSSII, SSIIa, SSIIb, SSIIIa), starch branching enzyme(BEIIb) and ADP-glucose pyrophosphorylase(AGPS1, AGPS2, AGPL2) were repressed in developing seeds, whereas starch degradation related genes such as ${\alpha}-amylase$(Amy1C, Amy3D, Amy3E) were induced. These results suggest that the reduction in yield and quality of rice in the future climate conditions is likely caused mainly by the poor grain filling by high temperature. Therefore, it is suggested to develop tolerant cultivars to high temperature during grain filling period and a new cropping system in order to ensure a high quality of rice in the future climate conditions.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.28 no.4
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• pp.391-418
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• 1983

Urea and ammonium sulfate without and with sulfur group, respectively, were compared with respect to their nutritive effects on the rice plants, Suweon 264 and Jinheung, under the nursery trial on the protected upland and lowland seedbed, the pot trials with their various combination ratios and with added sodium sulfate to urea and the trials on the paddy fields which have undergone urea and ammonium sulfate application for many years. The rice seedlings fertilized with ammonium sulfate surpassed those with urea in growth performance and nutrients absorption of the rice seedlings at nursery period. Such stimulating effect of ammonium sulfate on the growth and nutrients uptake was more remarkable under the upland nursery than under the lowland one. The pot trial with the various combination ratios of urea and ammonium sulfate revealed that the chlorophyll content in leaf blade increased with the increment of sulfate ratio in the combination and the sole application of urea caused the chlorosis of leaf which was more conspicuous in Suweon 264 than in Jinheung. Fertilized with the same active ingradient amount of nitrogen, the rice plants supplied with ammonium sulfate surpassed those with urea in the chlorophyll content consistently under the nursery, the pot and the paddy field trials. The photosynthesis of flag leaf at heading stage increased with the combination rate of ammonium sulfate in the pot trial. The sulfur applicated as supplementary element of nitrogen in the nursery, the pot and the field trials were observed to be in positive relationship to the nitrogen and potassium content, but to be in negative correlation to the calcium content. The sulfur content in the rice plants was higher at early growth stage and decreased with the advance in growth stage. The nitrogen content also showed a similiar tendency to the sulfur content, and the N/S ratio was higher at early growth stage than at later one. The N/S ratio was negatively correlated with the chlorophyll content. In the field experiment, ammonium sulfate surpassed urea in the number of productive tiller, dry matter production and unhulled rice yields, but much stimulating effect of ammonium sulfate on the grain production was shown to be less effective than that on the straw production. The nitrogen and major nutrients content in the rice straw at harvest were higher in the paddy field with long-term ammonium sulfate application than in that with long-term urea application, suggesting that the former might have greater potentiality in nutrients supply than the latter.

• Korean Journal of Agricultural Science
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• v.8 no.1
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• pp.3-10
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• 1981

In order to analyze growth and yield of rice population at the stand point of productive ecology, productive structure and growth rate of rice plants and effects of their related factors were studied. The results obtained were summarized as follows: 1. High crop growth rate was maintained throughout growing season when rice plants grew in population compared to a single rice plant. Since crop growth rate in rice stands were also higher at ripening stage, higher yields were obtained. 2. Higher crop growth rate of rice plants in population was maintained by the increase of leaf area rather than by net assimilation rate. 3. As the overgrowth of upper leaves of plant population in some rice varieties transmission of light into lower leaves was inhibited and thus most of them were eventually died before flowering. 4. In the case of rice population, the ratio of productive organ to non-productive organ, light transmission rate and nitrogen contents of active leaf blade were lower than individual rice plants under isolated condition.

• Korean Journal of Medicinal Crop Science
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• v.11 no.2
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• pp.167-170
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• 2003

'Jinsun', a new variety of safflower(Carthamus tinctoris L.), was developed by Kyonggi-do Agricultural Research and Extension Services in 2000. It was bred with pure line selection from Namwon local variety population. Jinsun is relatively resistant to Gleosporium carthami and has more flower head and higher ripened grain ratio. Its flowering date was June 22 in Hwaseong, Gyeonggido and contains more protein and linoleic acid relatively in grain compared with Cheongsu, check variety. Grain yield of Jinsun was 11% higher than Cheongsu.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.31 no.2
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• pp.226-230
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• 1986

Two near-isogenic lines with dark and pale green leaves, derived from the F$\_$7/ generation of wxl26 cross were compared on photosynthetic capacity, growth parameters, grain yield and yield-related characters. Dark green-leaved lines contained much greater content of chlorophyll a and b than pale green-leaved ones, but chlorophyll a to b ratio showed no difference between them. The photosynthetic nte per unit leaf area was higher in dark green-leaved lines than in pale green-leaved ones in the flag leaves at heading stage, but that per unit chlorophyll content showed reversed result. The crop growth rate from transplanting to heading was consistantly higher in the dark green-leaved lines, resulting from their greater net assimilation rate. Dark green-leaved lines produced greater number of panicles and spikelets per hill, out yielding pale green-leaved lines, but ripened grain ratio and 1000-grain weight showed no differences between those lines.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.18
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• pp.1-27
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• 1975

Experiment I: A field experiment was conducted in an attempt to find the effect of top-dressing at heading time in different levels of nitrogen application and of different positioned leaf blades formed by the treatment of leaf defoliation at heading time on the ripening and the yield of rice. The results obtained are as follows: 1. Average number of ears per hill and average number of grains per ear in different levels of nitrogen application were increased as the amount of nitrogen applied was increased. while the rate of ripened grains the yield of rough rice and the weight of 1, 000 kernels of brown rice were decreased respectively as the amount of nitrogen applied was increased. 2. The rate of ripened grains and the weight of 1.000 kernels of brown rice in different levels of nitrogen, top-dressing at heading time were larger than those in control and increased. The yield of rough rice although statistically significant differences were not recognized, were numerically increased. 3. The rate of ripened grains, the yield of rough rice, the weight of 1, 000 kernels of brown rice and the rate of hulling in different treatments of leaf defoliation were remarkably decreased as the degree of leaf-defoliation became larger. 4. The rate of ripened grains, the yield of rough rice, the weight of 1, 000 kernels of brown rice and the rate of hulling in different combinations of number of remained leaves positioned differently, formed the order of $L_1(flag leaf)>L_2>L_3>L_4$ when only one leaf blade was remained, and were increased as the positions of leaves were higher when two leaf blades. were, remained. 5. In case of decrease in the number of leaf blades positioned differently, by the treatment of leaf. defoliation, rate of ripened grains, the yield of rough rice, the weight of 1, 000 kernels of brown rice and the rate of hulling were increased as the area of remained leaves became larger and the nitrogen content of a leaf blade was increased. 6. There was a tendency that the increase in the amount of fertilizer application made the rate of ripened grains and the weight of 1, 000 kernels of brown rice reduced in any number of remained leaf blades, but the application of top-dressing at heading. time resulted in the reverse tendency. The yield of rough rice showed a tendency to be increased as the amount of basal dressing and top-dressing increased and for the application of top-dressing at heading time, the yield of rough rice was less at the smaller number of those. 7. The productivity effect of the rate of ripened grains and the yield of brown rice covered by leaf blades was more than 50 per cent and that of the. weight of 1, 000 kernels of brown rice was not more than 1.0 percent. As the amount of nitrogen application increased the. effect of leaf blades on the rate of ripened. grains and the weight of 1, 000 kernels of brown rice was increased. The effect of leaf blades on the weight of brown rice was increased as the amount of basal dressing-application, but the effect was decreased as the amount of top-dressing at heading time increased, 8. The productivity effects of different positioned leaf blades on the rate of ripened grains, the yield of rough rice and the weight of 1, 000 kernels of brown rice were in order of $L_1(flag leaf)>L_2>L_3>L_4$ the productivity effects of $L_1$ and $L_2$ had a tendency to be increased as the amount of nitrogen applied was increased. Experiment II: A field experiment was done in order to disclose the effect of the time of nitrogen application on yield component and the effect of different positioned leaves formed by leaf defoliation at heading time on the rate of ripened grains and the yield of rice. The results obtained are as follows: 1. Average number of ears per hill was increased in the treatment of nitrogen application from basal dressing to 22 days before heading and in the treatment of application distributed weekly. Number of grains was increased in the treatment of nitrogen application from 36 days to 15 days before heading. The rate of ripened grains was, lower in the treatment of nitrogen application from top-dressing to 15 days before heading than in that of non-application, was higher in the treatment of nitrogen application within 8 days before heading, and was the lowest in that of application 29 days before heading. The yield of rough rice was the highest in the treatment of nitrogen application from 29 days to 22 days before heading. The weight of 1, 000 kernels of brown rice was a little high in the treatment of application from 29 days to 8 days before heading. 2. The rate of ripened grains the yield of rough rice, the weight of 1, 000 kernels of brown rice and the rate of hulling in different treatments of leaf defoliation were remarkably decreased as the degree of leaf defoliation got larger and there were highly significant differences among treatments. There was also a recognized interaction between the time of nitrogen application and leaf defoliation. 3. In relation to the rate of ripened grains, the weight of 1. 000 kernels of brown rice and the rate of hulling in different numbers of remained leaves positioned differently and their combinations, the yield components were in order of $L_1(flag leaf)>L_2>L_3>L_4$ when only one leaf was remained, which indicated that the components were increased as the leaf position got higher. When two laves were remained, the rate of ripened grains, the yield of rough rice and rate of hulling were high in case of the combinations of upper positioned leaves, and the increase in the weight of 1, 000 kernels of brown rice appeared to be affected most]y by flag leaf. When three leaf blades were remained similarly the components were increased with the combination of upper positioned leaf blades. 4. In case of decreased different positioned leaf blades by treatment of leaf defoliation, there was a significant positive regression between the leaf area, the dry matter weight of leaf blades and the nitrogen contents of leaf blades, and rate of ripened grains and the yield of rough rice, but there was no constant tendency between the former components and the weight of 1. 000 kernels of brown rice. 5. The closer the time of fertilizer application to heading time, the more the rate of ripened grains and the weight of 1, 000 kernels was decreased by defoliation, and the less were the remained leaf blades, the more remarkable was the tendency. The rate of ripened grains and the weight of 1. 000 kernels was increased by the top-dressing after heading time as the number of remained leaf blades. When the number of remained leaf blades was small the yield of rough rice was increased as the time of fertilizer application was closer to heading time. 6. Discussing the productivity effects of different organs in different times of nitrogen application, the productivity effect of a leaf blade on the rate of ripened grains was higher as the time of nitrogen application got later, and in the treatment of non-fertilization the productivity effect of a leaf blade and that of culm were the same. In the productivity effect on the yield of brown rice, the effect of culm covered more than 50 percent independently on the time of nitrogen application, and the tendency was larger in the treatment of non-fertilizer. The productivity effect of culm on the weight of 1. 000 kernels of brown rice was more than 90 percent, and the productivity effect of a leaf blade was increased as the time of application got later. 7. The productivity effect of a leaf blade in different positions on the rate of ripened grains, the yield of rough rice and the weight of 1, 000 kernels of brown rice had a tendency to be increased as the time of application got later and as the position of leaf blades got higher. In the treatment of weekly application through the entire growing period, the rate of ripened grains and the yield of rough rice were affected by flag leaf and the second leaf at the same level, the but the weight of 1, 000 kernels of brown rice was affected by flag leaf with more than 60 percent of the yield of total leaves.

• 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.60 no.3
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• pp.257-265
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• 2015

This experiment was carried out to determine the optimum planting density for rice pot seedling cultivation in wheat-rice double cropping system in Honam plain area. A mid-late maturing rice variety 'Chinnong' was raised in pot seedling tray and conventional tray for 30 days, and then transplanted on June 25 in 2012 and 2013. Four different planting densities (15.2, 18.9, 21.6, and 25.3 hills per $m^2$) in pot seedlings were applied as treatment. Conventional tray seedling was implicated as control at a single planting density of 27.8 hills per $m^2$. In this experiment, the number of effective tillers was increased as planting density increasing, but stem diameter was decreased. Pot seedling showed higher stem diameter and effective tillers than the control. Heading dates of pot seedling plots were not significantly different between the planting densities but 2 days faster than the control. Culm length, number of panicles, panicle length, and ripening grain ratio were higher in pot seedling compared to the control, but 1000-grain weight showed no significant difference. Milled rice yields in pot seedlings ranged from 5.19 to $5.43\;t\;ha^{-1}$, and the highest yield was observed in 21.6 hills per $m^2$. Head rice ratios in pot seedlings and the controls were not significantly different. Above results on planting density of rice pot seedling cultivation would be applicable to wheat-rice double cropping and also to late transplanting cultivation of rice single cropping.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.4
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• pp.398-410
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• 1982

Summer crops grown in uplands are greatly diversified and show a large variation in difference with year and location in Korea. The principal factor for the variation is weather, in which precipitation and temperature play a leading role and such a weather factors as wind, sun lights also influence production of the summer crops. Since artificial control of weather conditions as a main stress factor for crop production is almost impossible, it must be minimized only by an improvement of cultivation techniques and crop improvement. Precipitation plays a role as one of the most important factor for production of the summer crops and it is considered in two aspects, drought and excess moisture. This country, which belongs to monsoon territory, necessarily encounter one of this stress almost every year, even though the level is different. Therefore, the facilities for both drought and excess moisture are required, but actually it is not easy to complete for them. On this account, crops tolerant to drought, excess moisture and pests should be considered for establishing summer crops. For the districts damaged habitually every season, adequate crops should be cultured and appropriate method of planting, drainage and weed control should be applied diversely. Injuries by temperature is mainly attributed to lower temperature particularly in late fall and early spring, although higher temperature often causes some damages depending upon the kind of crops. Sometimes, lower temperature in summer season playa critical role for yield reduction in the summer crops. However, certain crops are prevented to some extent from this kind of stress by improving varieties tolerant to cold, hot weather or early maturing varieties. As is often the case, control of planting time or harvesting is able to be a good management for escaping the stress. Lodging, plant diseases and pests are considered as a direct or indirect damage due to weather stress, but these are characters able to be overcome by means of crop improvement and also controlled by other suitable methods. In addition, polytical supports capable of improving constitution of agriculture into modern industry is urgently required by programming of data for the damages, establishment of damage forecasting and compensation system.