• 한국작물학회지
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• 제48권1호
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• pp.44-49
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• 2003

In vitro culture of panicle has been the method to accumulate starch and protein in immature grains by providing nutrients after florets crossed between remote genotypes artificially. Grain filling means embryo development and sucrose translocation from photosynthetic source, and starch manufacture in endosperm. The concentrations of sucrose used to culture immature rice panicle were 5, 10, 15, 20% and glutamine was 20 mM. When immature rice panicles at 5 days after flowering were cultured in distilled water with different concentrations of sucrose, glutamine 20 mM and MS medium with different concentrations of sucrose, glutamine 20 mM for 30 days the later was effective on grain filling. The optimal concentration of sucrose on grain filling in vitro culture of rice panicle was 10% and the weight of grain cultured was 10.14 mg that was corresponded to 57% of intact plant. In the method of treating plant growth regulators, the culture of immature rice panicle adding in MS medium with Kinetin, IAA, $\textrm{GA}_3$ were effective on grain filling than the culturing of immature rice panicle after submerging in solutions of Kinetin, IAA, $\textrm{GA}_3$ for 1day. When immature rice panicle was cultured in MS medium with sucrose 10% and Kinetin 46.47 $\mu$M it was effective on grain filling, respectively. The weight of grain cultured was 13.1mg that was corresponded to 75% of intact and germination rate was 51 %. When immature rice panicles were cultured in medium with different concentrations combined with Kinetin 4.65, 46.47, 464.7 $\mu\textrm{M}$, IAA 5.71, 57.08, 570.80 $\mu\textrm{M}$ for 30 days and in medium with IAA 5.71, 57.08, 570.80 $\mu\textrm{M}$ for 15 days after culturing in medium with Kinetin 4.65, 46.47, 464.70 $\mu\textrm{M}$ for 15 days the effect on grain filling was similar.

• 생명과학회지
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• 제11권4호
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• pp.311-315
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• 2001

To identify the effects embryo developmental stage and gelrite concentration on plant regeneration in seed culture of rice, mature and immature seeds of rice were cultured on the $N_{6}$ medium supplemented with2 mg/$\ell$ 2.4-D and different levels of gelrite(0.2~1.0%). The calli formed immature embryos were produced more plants than those from mature embryos. The maximum frequency of plant regeneration was achieved in the culture of the calli of immature embryos which was harvested at the 21$^{th}$ day after pollination. The plant regeneration on the medium with gelrite was more accelerate than that on the medium with agar. The highest frequency(55%) of plant regeneration was obtained from the calli transferred to the medium with 6g/$\ell$ gelrite.

• 한국작물학회지
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• 제54권4호
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• pp.357-365
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• 2009

본 연구는 립선별기에서 미숙립 선별능력을 높임으로써 도정효율 증진과 완전미율 향상을 꾀하고자 품종특성을 고려한 립선별기 선별체 최적 조건 구명 시험이 수행되었고, 다음과 같은 결과가 얻어졌다. 1. 립선별기의 선별능력은 현미립 두께에 절대적으로 의존되었는데, 조사된 시험재료의 현미 평균 두께는 1.79(농안)-2.16 mm(대립벼1호)의 분포를 보였다. 2. 품종별 차이는 있었으나, 대체적으로 현미의 평균 립두께가 2.08 mm이상일 경우 1.9 mm 선별체, 2.00-2.08 mm 범위일 경우 1.8 mm 선별체, 1.90-2.00 mm 범위일 경우 1.7mm 선별체, 그 이하일 경우 1.7 mm 이하의 선별체가 정립 손실을 최소화하면서(0.1%이내) 완전미율을 향상시킬 수 있는 조건인 것으로 판단되었다. 3. 백미 품위에 미치는 선별체 분리효과는 미숙립 비율이 높은 품종일수록 크게 발휘되었다. 4. 현미선별 체 눈 크기를 0.1 mm씩 증가시킬 경우 품종별로 현미선벌체 통과물중에 정상립이 포함되어 발생되는 정상립 손실율이 0.5% 수준까지는 현미선별체 눈금크기 증가에 따라 미미하게 증가하였으나, 이 눈금 수준이상에서는 선별체 눈금 0.1 mm 증가에 따라 정상립의 손실율이 급격히 증가하는 것으로 보아 정상립 손실율 0.5% 수준의 눈금이나 그 보다 0.05~0.10 mm 아래 눈금의 선별체가 적당할 것으로 생각되었다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2007년도 춘계학술대회 논문집
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• pp.415-416
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• 2007

• 한국농공학회지
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• 제17권1호
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• pp.3655-3665
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• 1975

This study was intended to develop a method for measuring the grain separating performance of threshers. The grain separating apparatus used for the experiment was designed and constructed, the function of which was to separate pneumatically mature and immature grain, chaff, straw, dust, and other impurities from the products of threshing. The apparatus has five material outlets where grains and impurities are fallen down by separation depending upon the specific gravity of the material white it moves above the outlets. The principle of design was to separate the mixture of mature grain, immature grain and chaff as distinct as possible, and to induce the mature grains onto the first outlet, the immature grains onto the second and the third, and the straw wastes onto the forth and the fifth outlets. The developed apparatus was tested to evaluate its separating performance with two rice varieties (Tongil and Mine-hikari) at different moisture levels and air velocities. The optimum conditions for operating the apparatus were found from experiment. The results are summarized as follows; 1. The degrees of separation, especially the amount of immature grain contained in the mature paddy, were dependent upon air speed delivered. The optimum air velocities for this apparatus for each levels of grain moisture contents were found from a series of experiments as follows; 14.7-15.3m/sec. for grain of 16 percent moisture content in wet basis, 15.3-16.0m/sec. for 20 percent, and 16.0-16.4m/sec for 24 percent. 2. Composition ratios determined based on the brine separating method was fairly well acted upon the developed apparatus, indicating its recollecting rate of the mature grains as 97.6 to 99.9 percent. The developed separatus acted similarly upon the two rice varieties which had different composition of immature paddy grain. In other words, the separating performance by the apparatus had a good correlation with the one by the brine separating method. 3. As immature grains were separated out unsatisfactory in these experiments than the brine separating method, further investigation may be needed to improve a separating performance of these materials. But the results obtained suggested a possibility of using the tester to replace the current hand separating method, ther eby enabling more consistent test results and also eliminating nearly all costly hand seperating operations.

• Animal cells and systems
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• 제2권3호
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• pp.309-313
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• 1998

We found some larvae of non-biting midges (Diptera: Chironomidae) that Injured rice crops by feeding on seeds and/or roots in the reclaimed rice fields in Seosan, Chungchongnam-do, Korea, in May 1997, Four instar larvae were collected and reared in the laboratory. This pest species of the rice plant was identified as a new species of Cricotopus, similar to C. sylvestris. The main differences are the color pattern of the abdominal tergites. Both adult and immature stages of the new species are described with illustrations.

• 한국환경농학회지
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• 제25권1호
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• pp.71-76
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• 2006

Environment friendly agriculture is nowadays a major fiend to sustain balanced agricultural ecosystem, keeping its productivity. This study was conducted to determine the optimum levels of nitrogen (N) application for improving rice productivity and reducing N loss through N application based on soil diagnosis. four levels of N were applied with 0, 50, 100 and 150% of recommended levels by soil testing in 4 different paddy soils (i.e. normal, sandy, ill-drained and immature soils). Across N treatments, the greatest grain yield was observed in sandy soil and the lowest in ill-drained soil. The grain yield tended to decrease with increasing N application from 50% to 150% of recommended levels, except ill-drained soil. To ensure maximum yield the optimum levels of N application were estimated at 120 kg, 153 kg and 173 kg $ha^{-1}$ in normal, immature and sandy soil, respectively.

• Applied Biological Chemistry
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• 제36권3호
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• pp.197-202
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• 1993

들깨에 존재하는 brassinosteroid 활성물질을 탐색하기 위하여 미숙종자를 MeOH로 추출하고, 이 추출물을 rice inclination test를 지표로, 용매 분획, silica gel adsorption chromatography, Sephadex LH-20 chromatography, charcoal adsorption chromatography, Bondesil chromatography 등의 수법으로 brassinosteroid 활성물질을 정제한 다음, silica gel 흡착 chromatography로 활성성분을 분리하고, 각 활성획분에 대해 HPLC에 의해 활성본체를 구명한 결과, main brassinosteroid로 castasterone이 그리고 minor brassinosteroid로 homodolicholide가 최초로 동정되었다. 들깨에 함유된 brassinosteroid의 함량은 brassinolide로 환산하여 생체중량 g당 $0.5{\sim}0.8\;ng$ 수준이었다.

• Journal of Plant Biotechnology
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• 제1권1호
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• pp.46-55
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• 1999

The expressed sequence tags(ESTs) from immature seed of rice, Oryza sativa cv Milyang 23, were partially sequenced and analyzed by homology. As of 1998, the partial sequences of about 6,600 cDNA clones were analyzed from normal and normalized immature seed cDNA libraries. About 2,200 ESTs were putatively identified by BLASTX deduced amino acid sequence homology analysis. About 20% of them were putatively identified as storage proteins. Also the clones were highly homologous to genes involved particularly in starch biosynthesis, glycolysis, signal transduction and defenses. Compared to 35% of redundancy in the ESTs of normal cDNA library, that from the substracted library was 15%. The Korea Rice Genome Network is maintained to provide the updated information of sequences, their homologies and sequence alignments of ESTs. For the stable expression of transgene in rice, diverse vectors were developed for overexpression, targeting and gene dosage effect with transit peptides (Tp) and matrix attachment region (MAR) sequence from chicken lysozyme locus. The rice calli were transformed via Agrobacterium tumefaciens LBA4404(pSB1) with the triparental mating technique and selected by herbicide resistance. The green fluorescent protein(GFP) gene in expression vector under the control of rbcS promoter-Tp was overexpressed upto 10 % of the total soluble protein. In addition, the Tp-sGFP fusion protein was properly processed during translocation into chloroplast. The expression of sGFP in the presence of MAR sequences was analyzed with Northern and immunoblot analysis. All the lines in which sGFP transgene with MAR sequence, showed position independent and copy number-dependent expression, while the lines without MAR showed the varied level of expression with the integration site. Thus the MAR sequence significantly reduced the variation in transgene expression between independent transformants.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.301-301
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• 2017

Subspecific difference of the percentage of white immature kernels (WIK) between japonica and indica rice cultivars was analyzed in relation to ripening temperature and yield characters. Thirty-three Chinese and 10 Japanese rice cultivars, including 32 japonica and 11 indica, were cultivated with three different cropping seasons for three years. The results were as follows: (1) Indica had less number of panicles, larger number of spikelets per panicle with higher yield, and longer and narrower kernels than japonica. In japonica, Chinese cultivars had less number of panicles and larger number of spikelets per panicle than Japanese cultivars. In addition, WIK was significantly higher in Chinese cultivars than in Japanese cultivars, because of the higher percentage of milky white kernels, even at similar temperature conditions during ripening. On the other hand, WIK in indica was not significantly different between the production areas and between the cropping seasons. (2) Regardless of subspecies, WIK in a large number of Chinese cultivars increased with increasing temperature during ripening within 20 days after heading, while this relation was uncommon in Japanese cultivars, showing the low temperature response. However, some Chinese cultivars had the low WIK with the low temperature response. (3) WIK in japonicawas positively correlated with 1000-kernel weight, spikelet density, kernel width and thickness, but negatively correlated with panicle length and grain filling percentage, while in indica it was positively correlated with panicle number per area, grain filling percentage, brown rice yield and kernel width, but negatively correlated with kernel length. These results indicated that WIK in both subspecies had a close relation to kernel size, and that WIK was high in japonica cultivars with wide and thick kernels and in indica cultivars with short and wide kernels.