• Journal of Microbiology and Biotechnology
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• v.17 no.10
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• pp.1645-1654
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• 2007

The total methylotrophic population associated with rice plants from different cultivars was enumerated at three different stages: vegetative, flowering, and harvesting. The bacterial population in the leaf, rhizosphere soil, endophytic in the stem and roots, and epiphytic in the florets and grains were determined from four rice cultivars, Il-mi, Nam-pyeoung, O-dae, and Dong-jin, sampled from three different field sites. The methylotrophic bacteria isolated on AMS media containing 0.5% methanol as the sole carbon source uniformly showed three distinct morphologies, which were recorded as separate groups and their distribution among the various samples was determined using the ecophysiological index. The growth stage at the time of sampling had a more significant effect on the methylotrophic population and their distribution than the field site or cultivar. A similar effect was also observed for the PPFMs, where their population in different plant parts increased from V10 to R4 and then decreased towards stage R9. A canonical discriminant analysis of the PPFM population from different parts of rice showed clear variations among the cultivars, sampled sites, and growth stages, although the variations were more prominent among the growth stages.

• Journal of the East Asian Society of Dietary Life
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• v.4 no.3
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• pp.67-74
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• 1994

The sensory and instrumental characteristics of Jeung pyun made from varietal difference in physicochemical characteristics of rice grain were investigated to obtain the basis information for developing various rice cultivars adaptable to rice food processing. In sensory evaluation of Jeung pyun, aroma, springiness, and stickiness revealed significant difference between the rice cultivars. Acceptability of springiness was highly correlated with amylose content. And loaf volume of Jeung pyun was also highly correlated with the protein content of rice grain. In textural analysis, Jeung pyun made from the higher amylose content rice became harder during storage. Jeung pyun made from the lower alkali digestible rice showed the more sticky and elastic.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.4
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• pp.837-844
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• 1999

The textural properties and retrogradation of injeulmi(Korean traditional waxy rice cake) made from various waxy cultivars were examined to compare the varietal difference. Injeulmi made from Shinsun chalbyeo and Whasunchalbyeo were exhibited relatively soft texture, while Taichung Sen Glu I and Yuk donongrimna were shown high adhesivness. Intermediate or long grain rice such as Yukdonongrimna, Hangangchalbyeo and Taichung Sen Glu I had a tendency to be rapidly retrogradatated as compared with short grain rice, Shinsunchalbyeo and Whasunchalbyeo. Amylogram characteristics of these intermediate or long grain rice cultivars were shown high value in consistency and low value in setback. Studies per formed by various cookery procedure demonstrated that injeulmi made from cooked waxy rice was softer and delaying retrogradation than made from waxy rice flour.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.4
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• pp.309-315
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• 1999

Rice seedling test was conducted to check the loging tolerance at ripening stage through evaluating the root characters. Thirteen Korean and foreign rice cultivars with direct seeding adaptable or high quality characteristics were grown in a cell pot and under submerged paddy. The root characters and pushing resistance of rice hill were determined at seedling and ripening stage, respectively. The diameter of crown root at the 7th and 8th leaf stages was thicker in lodging tolerance cultivars than those of others and showed significant-positive correlation with both pushing resistance and crown root diameter of mature plants. Also, the tensile strength of crown root at the 7th and 8th leaf stage showed highly positive correlation with the tensile strength of crown root of mature plants. The number of crown root at 7th leaf stage was significant-positively correlated with that of mature plant. The diameter of seminal root was not significantly correlated with the diameter of crown root throughout the whole growth stage. These results indicate that the diameter, tensile strength and number of crown root associated with root lodging tolerance can be detected with the seedling at about 7th or 8th leaf stage, and the seedling test using the cell pot is an useful and practical method to select lodging tolerant cultivars or lines of rice based on root characters, especially diameter of crown root.

• KSBB Journal
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• v.6 no.2
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• pp.123-128
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• 1991

The production of bassinosteroid-like substances of two hybrid types of Korean rice, Jangseongbyeo, Taebackbyeo were investigated. The shoots at the maximum tillering stage were extracted and purified by solvent fractionation, silica gel adsorption chromatography Sephadex LH-20 chromatography, charcoal adsorption chromatography, Bondesil chromatography and HPLC of reverse phase, successively. Biological activities of each purification step were monitored by the rice lamina inclination test. Higher activities against the rice lamina inclination test in the each purification step showed that the shoots of two cultivars biosynthesize brassinosteroids. Two cultivars also showed a similar distribution of biological activities of endogenous brassinosteroids detected by HPLC.

• Korean Journal of Agricultural Science
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• v.46 no.4
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• pp.791-798
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• 2019

This experiment was conducted to find out the difference between roughage productivity and feed value by using two domestic forage rice cultivars in a mid-west reclaimed rice field in Korea. During the growing period, Na⁺ content in soil showed no significant difference between the two cultivars; however, the K⁺ content in the soil was significantly lower than that in which the Mogwo was grown. The tiller number was 45.5 to 58.8, which was higher than that of Mogyeong, and the leaf number was higher than that of Mogyeong. The dry matter yield per 10 a was 1,338 kg for Moggyang and 1,532 kg for Mogwoo. At the harvest time, the crude protein yield per 10 a produced 108 kg of Mogyang and 170 kg of Mogwoo, and the total digestion nutrient (TDN) yield per 10 a also produced about 617 kg of Mogyang and 880 kg of Mogwoo. To sum up the above results, Mogwo, which has many tiller numbers and leaf numbers, has a high dry matter production, a relatively low neutral detergent fiber (NDF) and acidic detergent fiber (ADF), and a high crude protein yield and TDN yield, and it was better when cultivating the forage rice cultivars in reclaimed land.

• Journal of Crop Science and Biotechnology
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• v.10 no.4
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• pp.281-286
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• 2007

Gibberellins are growth hormones that play a pivotal role in the growth and development of plants. Present investigations were carried to check the effect of nitrogen(N) and silicon(Si) on bioactive $GA_1$ and its immediate precursor $GA_{20}$ at different growth stages of two rice cultivars with different maturity traits. It was observed that the endogenous bioactive $GA_1$ level gradually increased during vegetative stage and anthesis stage of both Junghwabyeo(early flowering cultivar) and Daesanbyeo(late flowering cultivar). However, the $GA_1$ and $GA_{20}$ content start decreasing during the seed filling stage in both rice cultivars, which indicated a possible relationship of bioactive $GA_1$ and floral development. Our results also confirmed that early 13-hydroxylation pathway was operated at all developmental stages of rice plant. Variation in the levels of the endogenous gibberellins in rice shoots were measured by GCMS-SIM using $^2H_2$-labeled gibberellins as internal standards. Combined application of N and Si enhanced growth parameters and reduced lodging index of both rice cultivars. It was thus concluded that the level of physiologically active $GA_1$ increased during vegetative and early reproductive stage, but starts declining at seed filling stage.

• Journal of Crop Science and Biotechnology
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• v.10 no.1
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• pp.45-49
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• 2007

Silicon is one of the key elements for healthy growth and development in rice crops. We analyzed the effect of silicon(Si) on some growth parameters, plant mineral contents, and bioactive gibberellins in three rice cultivars. Silicon was applied at the rates of 0 kg/0.1ha(control), 40 kg/0.1ha, and 80 kg/0.1ha throughout the course of experiment. Plant growth parameters were enhanced by the application of elevated Si, though plant height and culm length were more favorably affected than the respective dry weights. The plant mineral contents analyzed also increased in treatments where Si was applied without potassium, demonstrating that Si application promotes the absorption of these minerals in rice crops. The endogenous gibberellins measured in our study showed that $GA_1$ is the only bioactive GA form present in rice seedlings. The endogenous $GA_1$ and its precursor $GA_{20}$ contents increased after Si application. However, this increase in endogenous $GA_1$ and $GA_{20}$ contents, and plant growth parameters were different according to the rice cultivars. Our results indicate that Si is a beneficial element in rice nutrition and that different cultivars of Oryza sativa show differential responses to Si nutrition in terms of their growth and development.

• Korean Journal of Agricultural Science
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• v.49 no.3
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• pp.511-520
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• 2022

Insect-resistant transgenic rice (Bt-T) expresses a toxic protein (mcry1Ac1) derived from the soil bacterium Bacillus thuringiensis found in the rice cultivar Dongjin with an insecticidal property against rice leaf roller (Cnaphalocrocis medinalis). In this study, to investigate the impact of Bt-T on non-target organisms, the feed and oviposition preferences and biological parameters of brown planthopper (Nilaparvata lugens Stål) were comparatively analyzed in four rice cultivars: Dongjin (parent variety), Ilmi (reference cultivar), Chinnong (brown planthopper resistant cultivar) and Bt-T. In the Bt-T and Dongjin cultivars, the feed preferences were 32.4 ± 8.3 and 34.1 ± 6.8%, and the oviposition preferences were 32.5 ± 5.1 and 30.0 ± 5.3% respectively, and there was no statistical significance between these rices. Additionally, in the Bt-T and Dongjin cultivars, the total lifespans from egg to adult were 39.5 ± 6.9 and 40.0 ± 5.8 days, and the weights of adult females were 1.78 ± 0.14 and 1.72 ± 0.16 mg, respectively. Therefore, there was no statistical difference in the biological parameters between these two varieties. Overall, the results indicate that the insect-resistant transgenic rice (Bt-T) did not negatively affect the reproduction and life cycle of brown planthopper, a non-target organism.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.31 no.4
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• pp.403-407
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• 1986

The rice leaf color, which was one of main factors to determine application time of fertilizers, was analyzed in visible region, while the distinction of photosynthetic pigments controlling the rice leaf color was separated by T.L.C. The light absorption peaks of ethyl ether extracts of rice leaf blades were occurred in 413, 432, 453 and 662nm. Especially, the maximal light absorption was 432nm in blue and 662nm in red region. The both light absorption ratios (blue to red region) was not greatly different among rice ecotypes, whereas decreasing tendency in increased fertilization was observed. There was a significant negative correlation between the both light absorption ratios and the values of color chart, and the content of chlorophyll in rice leaf blades. The composition ratio of chorophyll was larger than that of carotenoid at heading stage, and the carotenoid was larger than the chlorophyll at 30 days after heading. The composition ratio of chlorophyll among photosynthetic pigments according to rice ecotypes, Japonica x Indica cultivars were larger than Japonica cultivars at heading stage, and Japonica cultivars were larger than Japonica x Indica cultivars at 30 days after heading, while carotene was vice versa.