• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.3
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• pp.180-183
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• 2001

This study was conducted to find out the effect of ripened grain and rice quality by the breeding of rice dust mite (Steneotarsonemus spinki). Growth temperature of sample (Suwon 441 and Ilpumbyeo) was maintained from 22$^{\circ}C$ (during night) to 26$^{\circ}C$ (during day) in a controlled phytotron. Plant hight and number of panicle could not showed the difference by the discoloration degree of leaf sheath. But number of spikelet was reduced affected by discoloration degree of leaf sheath. Ratio discoloration of grain was increased according to circumstances more discoloration degree of leaf sheath in Suwon 441 then Ilpumbyeo. The perfect rice grain was observed to similar Suwon 441 and Ilpumbyeo in the IV degree of ratio discoloration of grain, but less Suwon 441 than Ilpumbyeo in III and II, in such a case comparison between coloration and discoloration.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.1
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• pp.20-27
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• 1982

Two rice varieties were planted and four degrees of defoliated tiller num ber ratio and another four levels of defoliation-panicle removal tiller number ratio were made at heading stage of know the possibility of translocation of photosynthetic products between tillers during grain filling stage of rice plant. The more tillers defoliated in a hill, the less matured grain ratio and the less grain weight per panicle of normal tillers were found. But the matured grain ratio and the grain weight per panicle of tillers defoliated partly in a hill showed higher than those of tillers of completely defoliated plant. No differences of the matured grain ratio and the grain weight per panicle were found between different levels of defoliation-panicle removal tiller number ratio in a hill. But the matured grain ratio and the grain weight per panicle of tillers of completely defoliated plant were significantly lower than those of tillers of partly defoliation-panicle removal treatments. These results indicated that the translocation of photosynthetic products between tillers was possible during grain filling period in rice plant. Source-sink relationship can be applied to interpret the result obtained in this study.

• Korean Journal of Soil Science and Fertilizer
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• v.1 no.1
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• pp.125-128
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• 1968

The effect of number of leaf after heading time on the growth of residual part and translocation of carbohydrates were investigated with water culture condition. Mutual shading and root rot were prevented. The results may be summerized as follows; 1. The ratio of ripened grain in the plot of no-leaf, flag leaf, two-leaf(flag and 2nd leaf) and three-leaf (flag, 2nd and 3rd leaf) was 38.8, 74.7, 83.9 and 87.0% respectively. The thousand grain weight was 21.3g, as the lowest value in no-leaf plot and was 28.7g in all other plots. 2. The accumulation of carbohydrate translocated in culm was increased by increment of leave-cutting, whereas the weight of culm was decreased. 3. It was suggested that healthy flag and 2nd leaf can keep the ratio of ripened grain around 80 percent.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.29 no.1
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• pp.19-24
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• 1984

Experiment was conducted to know the interaction of temperature and solar radiation for spikelet formation of rice in different location. Under the Korea climatic conditions both number of spikelets and percentage of ripened grains affected yield of rice. Percentage of ripened grains was the most significant limiting factor in Tongil type rice varieties and the lower number of spikelets in japonica type varieties. The number of spikelets increased as amounts of solar radiation increased during the reproductive stage, as daily air temperature decreased from 23 to 28$^{\circ}C$, or as climatic consumption index (CCI) value decreased. CCI calculated with critical temperature of 1$0^{\circ}C$ and solar radiation was more closely correlated with the number of spikelets compared to CCI calculated with sunshine hours instead of solar radiation. CCI during the 15 days before heading was more closely related with the number of spikelets compared to CCI during the 30 days before heading.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.18
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• pp.54-87
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• 1975

The effects of various weather factors on yield components of rice, year variation of yield components within regions, and regional differences of yield components within year were investigated at three Crop Experiment Stations O.R.D., Suweon, Iri, Milyang, and at nine provincial Offices of Rural Development for eight years from 1966 to 1973 for the purpose of providing information required in improving cultural practices and predicting the yield level of rice. The experimental results analyzed by standard partial regression analysis are summarized as follows: 1. When rice was grown in ordinary seasonal culture the number of panicles greatly affected rice yield compared to other yield components. However, when rice was seeded in ordinary season and transplanted late, and transplanted in ordinary season in the northern area the ratio of ripening was closely related to the rice yield. 2. The number of panicles showed the greatest year variation when the Jinheung variety was grown in the northern area. The ripening ratio or 1, 000 grain weight also greatly varied due to years. However, the number of spikelets per unit area showed the greatest effects on yield of the Tongil variety. 2. Regional variation of yield components was classified into five groups; 1) Vegetation dependable type (V), 2) Partial vegetation dependable type (P), 3) Medium type (M), 4) Partial ripening dependable type (P.R), and 5) Ripening dependable type (R). In general, the number of kernel of rice in the southern area showed the greatest partial regression coefficient among yield components. However, in the mid-northern part of country the ripening ratio was one of the component!; affecting rice yield most. 4. A multivariate equation was obtained for both normal planting and late planting by log-transforming from the multiplication of each component of four yield components to additive fashion. It revealed that a more accurate yield could be estimated from the above equation in both cases of ordinary seasonal culture and late transplanting. 5. A highly positive correlation coefficient was obtained between the number of tillers from 20 days after transplanting and the number of panicles at each(tillering) stage 20 days after transplanting in normal planting and late planting methods. 6. A close relationship was found between the number of panicles and weather factors 21 to 30 days, after transplanting. 7. The average temperature 31 to 40 days after transplanting was greatly responsible for the maximum number of tillers while the number of duration of sunshine hours per day 11 to 30 days after transplantation was responsible for that character. The effect of water temperature was negligible. 8. No reasonable prediction for number of panicles was calculated from using either number of tillers or climatic factors. The number of panicles could early be estimated formulating a multiple equation using number of tillers 20 days after transplantation and maximum temperature, temperature range and duration of sunshine for the period of 20 days from 20 to 40 days after transplantation. 9. The effects of maximum temperature and day length 25 to 34 days before heading, on kernel number per panicle, were great in the mid-northern area. However, the minimum temperature and day length greatly affected the kernel number per panicle in the southern area. The maximum temperature had a negative relationship with the kernel number per panicle in the southern area. 10. The maximum temperature was highly responsible for an increased ripening ratio. On the other hand, the minimum temperature at pre-heading and early ripening stages showed an adverse effect on ripening ratio. 11. The 1, 000 grain weight was greatly affected by the maximum temperature during pre- or mid-ripening stage and was negatively associated with the minimum temperature over the entire ripening period.

• Korean Journal of Agricultural Science
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• v.1 no.1
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• pp.9-26
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• 1974

1. Results in Nursery This experiment was carried out on the effect of the seed treament, soil preparations, kinds of covering soil and inside covering methods in two rice varieties, 'Tongil' and 'Akibare' to find out the most reasonable model of the flat nursery bed, with which lower cost is required comparing with the tunnel nursery. The results obtained are as follows: (1) The seedling of all plots of the ordinary seed were very poor compared to the plots of sprouted seed. (2) In case that the variety 'Tongil' was cultivated on the dry nursery bed, the good seedling percentage and the plant height rat io were significantly increased but the other characteristics of the seedling were not noticeable. (3) The kinds of the covering soil had not an effect on the seedling growth significantly. (4) Inside straw mulching was seemed effective for the protection in the case of the extreme high temperature and heavy rain fall, even though there was not significant differences between inside straw mulching and no treatments at the flat type nursery. (5) Difference of seedling growth between the flat type nursery and the tunnel type nursery was not significant. And it's reason was thought that the covering period of polyethylene film was short in semi hot nursery for the common early transplanting cultivation of rice. (6) The percentage of good seedling was higher at 'Akibare' than 'Tongil', variety but the number of seedling leaf and the seedling growth ratio in height were significantly increased in the variety 'Tongil'. The other seedling characters between there two varieties were not significantly different. 2. Results after transplanting This experiment was conducted to study on the ripening percentage, rice yield and disease, appearance of the seedling from sprouted seed plots including common irrigated nursery as check plot after transplantnig. The results obtained are summarized as follows: (1) The rice yield, the yield components and the appearance of leaf discoloration of both varieties, 'Tongil' and 'Akibare' were slightly betterat the plot of the standard tunnel nursery than that of the flat nursery with inside mulching or the among these three plots. (2) For 'Tongil' variety, the ripening percentage and the rice yield were significantly decreased at the common irrigated nursery compared with semi hot nursery. (3) The ripening percentage and the rice yield of 'Akibare' contrasted with 'Tongil' were significantly decreased at thesemi 'hot-nursery compared with common irrigated nursery. The main reason was thought to be the injury of the rice stripe disease (Rice stripe disease virus). Considering above mentioned experimental result, the seedling of 'Tongil' must be cultivated on the semi bot nursery for better ripening percentage as well as rice yield and for prevention of red discoloration. And as a model of semi hot nursery, the polyethylene covering nursery of standard tunnel type is most desirable but that of flat type with inside straw mulching is thought to be desirable too.

• Korean Journal of Agricultural Science
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• v.2 no.1
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• pp.111-123
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• 1975

6 years data on the plant growth and grain yield of 13 rice varieties were investigated to define the relations between meteological conditions and plant growth of rice including grain yield. The results obtained are summarized as follows; 1. Variation of average temperature by years showed great number at early and middle July, middle August and early November, however smallest figure at late June and late July. And that of sunshine hours by years were least at late June and late July, and largest at middle July. 2. Among rice yield components variation of panicle number per hill by years was biggest and that of 1000 grain weight least. Rate of variation of plant growth and rice yield was different by rice varieties. 3. Direct effects on rice yield was greatest at maturing ratio and next at 1000 grain weight. The effects of yield factor on the rice yield wers different by years. 4. Higher temperature and longer sunshine delayed the miaxmum tillering stage but shortened the days from seeding to heading. 5. A significant negative correlation was recognized between the number of panicles per hill and average temperature of 11 to 40 days after transplanting, and number of grains per panicle was correlated with the average temperature of 11 to 70 days after transplanting. High temperature before heading time showed atime decreased maturing ratio. 6. Accumulated temperature was highly correlated with 1000 grain weight in all season. Highest positive correltaion was recognized between grain yield of rice and average temperature of 61 to 70 days after transplanting but correlations between rice yield and average temperature after heading stage were negative. 7. Highly significant correlations were confirmed between maturing ratio and sunshine hours of 31 to 50 days as well as 61 to 70 days after transplanting, and maturing ratio was highly correlated with accumulated hours of sunshine. Correlation between rice yield and hours of sunshine was significant at 51 to 60 days after transplanting.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.23 no.2
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• pp.61-67
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• 1978

Drainage furnished air to provide favorable soil environment forfice growth at the late stage. A heavier fertilizer application and a denser plant density increase. Yield and yield component element by root activities and various substence productive element under sub-drainage.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.33 no.3
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• pp.222-228
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• 1988

This experiment was carried out to investigate the effects of N levels (0,10,20,30kg/10a) and N split rates [the rates of basal＋top dressing 15 days after transplanting (DAT) : top dressing 25 days before heading (DBH) was 100 : 0, 80 : 20, 60 : 40 ] on the growth, yield, yield components, and N uptake of Seomjinbyeo (J) and Samgangbyeo (I${\times}$J). The maximum tillering stage occurred in the middle of July in both varieties, but Samgangbyeo showed the second maximum tillering stage in the middle of August probably due to the retarded early growth caused by low temperature in the tillering stage and to favoring temperature in August. Grain yield of Seomjinbyeo was similar among the N levels from 10 to 30 kg/10a without occurrence of rice blast and lodging, but that of Samgangbyeo increased as N level increased upto 30 kg/10a. Grain yield of Seomjinbyeo was higher when N was applied three times (basal and two top dressings 15 DAT and 25 DBH) compared with two times (basal and top dressing 15 DAT), but that of Samgangbyeo was not different among the N split rates. Total N uptake and the proportion of fertilizer N to the total N uptake increased as N level was higher. N uptake tended to be higher as proportion of basal＋top dressing 15 DAT increased in early growth stage, but it was higher as proportion of N applied 25 DBH increased in the late growth stage. The N efficiency to produce grain per absorbed N unit decreased as N level decreased in Seomjinbyeo, but similar in Samgangbyeo.

• The Journal of Natural Sciences
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• v.5 no.1
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• pp.15-28
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• 1992

토양에 20년간 3요소+생고를 처리하였을때 토양의 화학적 성분, 공극율, 입단구조가 잘 발달되었다. 또한 이 처리에 의하여 CGR은 영화분화기때 가장 높았으나 무처리구나 3요소단용구에서는 전생육기간을 통하여 계속 증가하는 경향을 띈 반면 3요소+생고처리구에서는 영화분화기이후 계속 감소 하는 추세을 나타내고 있다. 현미수량에 있어서는 3요소+생고처리에 의하여 11%의 증가효과가 있었으며 이것은 주로 이삭의 일.이차기경의 분화수가 증가하였기 때문이었다. 또한 미립형태에 있어서도 완전미의 비율이 높았는데 이것은 등숙속도와 매우 밀접한 관계가 있어서 등숙속도가 빠를수록 심백미, 복백미 및 동할미가 많았다. 3요소 + 생고속도는 40DAH이었다.