• Proceedings of the Korean Society of Crop Science Conference
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• 2000.11a
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• pp.147-148
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• 2000

• Proceedings of the Korean Society of Crop Science Conference
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• 2001.05a
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• pp.248-249
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• 2001

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2006.06a
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• pp.23-24
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• 2006

• Proceedings of the Korean Society of Crop Science Conference
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• 2018.10a
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• pp.173-173
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• 2018

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.274-274
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• 2022

• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.3
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• pp.214-220
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• 1999

Rice production in Korea has markedly increased during the last two decades due to newly developed high yielding varieties and improved production technology. This experiment was conducted to determine the potential of tropical japonica germplasm in enhancing the yield of temperate japonica. The yield performance of two tropical japonicas (IR 65597-29-3-2 and IR66154-52-1-2) and one temperate japonica (Dongjinbyeo) was compared at different plant densities and nitrogen levels under Korean environmental conditions. Although tropical japonicas showed low tillering habit and large panicles, they had similar leaf area index and dry weight at heading stage to Dongjinbyeo of the high tillering type indicating that there was not much difference between tropical and temperate japonica in terms of biomass production. The highest milled rice yield of 6.15 t/ha was obtained from Dongjinbyeo at a high nitrogen level with less planting density (220 kg N/ha and 30 $\times$ 15 cm). However, those of the two tropical japonicas were 5.36 t/ha at the condition of 165 kg N/ha and 30 x 10 cm planting density and 5.06 t/ha at the condition of 165kgN/ha and 15 x 15 cm planting density, respectively. Ripened grain of tropical japonicas ranged from 65 to 87%, while that Dongjinbyeo ranged from 82 to 97% under Korean conditions.

• Korean Journal of Food Science and Technology
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• v.40 no.5
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• pp.516-521
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• 2008

This study was conducted to optimize the analysis condition and quantify the 2-acetyl-1-pyrroline (2AP) in the brown aroma rice. Extraction effect of the solvent for 2AP was the order of ethanol>acetonitrile>methanol in the range from 30 to $90^{\circ}C$. In the extraction time of 15, 30, 60, and 90 min, the 30 min had the highest 2AP concentration, and it was decreased according to lapse of time. At grinding time, 5 sec resulted in highest 2AP concentration. It was recommended that five sec grinding time, using ethanol, at $90^{\circ}C$ for 30 min was the optimization conditions to quantify the 2AP. Hyangmibyeo2ho and Aranghyangchalbyeo were mild aroma. In the foreign aroma rice, 11 of 19 accessions of Indica types and 2 of 6 accessions of Japonica types were more than mild aroma. Finally, 30 accessions of aroma rice were selected based on their 2AP concentration and agronomic traits.

• Korean Journal of Agricultural Science
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• v.48 no.2
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• pp.283-297
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• 2021

Investigation of genetic diversity and molecular characterization in high yielding rice varieties is important for their identification. The experiment was conducted during 2016 - 2017 to analyse the genetic diversity of fifteen high yielding rice varieties in Bangladesh by using random amplification of polymorphic DNA (RAPD) markers. Polymorphism was revealed in 12 RAPD primers out of 30, whereas no other reaction was detected on the remaining 18 primers. The 40 out of 45 bands (88.89%) polymorphics were produced by the primers and ranged from 50 to 100%. The maximum number of polymorphic bands was produced by the primer OPB-18 whereas the lowest number of polymorphic bands belonged to OPC-12. The genetic similarity coefficients were determined with the RAPD data, which ranged from 0.47 to 0.94. The unweighted paired group of arithmetic means (UPGMA) dendrogram presented the studied rice varieties into two major clusters. Moreover, the value of Nei's genetic diversity is 0.26 and the Shanon information index is 0.41. The study produced distinct positions, suggesting that the genotypes were different from each other. The results indicated that these markers could be efficient for comparing the genetic relationships, patterns of variation, and measurement of genetic distance among rice varieties. Considering all of these results, RAPD analysis is found to be an effective tool for estimating the genetic diversity of different rice varieties. The outcomes of this research may contribute to the germplasm data of rice accessions and a future breeding program of rice genotypes.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2021.04a
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• pp.38-38
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• 2021

The seeds of rice with variable status were examined the germination rate after 10 years of long-term storage (-18℃) conservation. For seeds of wild relatives, 2 accessions were examined and germination rate of all accessions showed no changed after freezing conservation. For seeds of native germplasm, 1,259 accessions were examined and germination rate of 696 accessions was increased or showed no change after 10 years of long-term storage. Germination rate of 432 accessions was decreased with below 15% of initial germination rate. For 79 accessions of native germplasm, germination rate of seeds was decreased with above 15% of initial germination rate after 10 years of long-term storage, which is needed to be rejuvenated. For seeds of developed varieties, 873 accessions were examined and germination rate of 486 accessions of developed varieties was increased or showed no change after 10 years of long-term storage. Germination rate of 251 accessions was decreased with below 15% of initial germination rate. For 25 accessions of developed varieties, germination rate of seeds was decreased with above 15% of initial germination rate after 10 years of long-term storage, which is needed to be rejuvenated. For seeds of developed line, 2,131 accessions were examined and germination rate of 1,245 accessions of developed line was increased or showed no change after 10 years of long-term storage. Germination rate of 588 accessions was decreased with below 15% of initial germination rate. For 96 accessions, germination rate of seeds was decreased with above 15% of initial germination rate, which is needed to be rejuvenated.

• Plant Resources
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• v.6 no.1
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• pp.16-26
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• 2003

Molecular markers are useful tools for evaluating genetic diversity and determining cultivar identity. Present study was conducted to evaluate the genetic diversity within a diverse collection of rice accessions used for Korean breeding programs. Two hundred eighty-seven rice cultivars, composed of temperate japonica, tropical japonica, indica, and Tongil-type of Korean crossing parents were evaluated by means of 15 simple sequence repeat (SSR) markers. A total of 99 alleles were detected, and the number of alleles per marker ranged from 4 to 11, with an average of 6.6 per locus. Polymorphism information content (PIC) for each of the SSR markers ranged from 0.2924 to 0.8102 with an average of 0.5785. These results, with the result that use of only 15 SSR markers made all rice cultivars examined could be uniquely distinguished, imply the efficiency of SSR markers for analysis of genetic diversity in rice. Cluster analysis was performed on similar coefficient matrics calculated from SSR markers to generate a dendogram in which two major groups corresponding to japonica (Group I) and indica and Tongil type rice (group II) with additional subclasses within both major groups. The narrowness of the Korean breeding germplasm was revealed by the fact that most of the Korean-bred and Japan-bred temperate japonica cultivars were concentrated into only 2 of the sub-group I-1 (143 cultivars) and I-2 (58 cultivars) among six sub-groups in major group of japonica. This is because of the japonica accessions used in this study was a very closely related ones because of frequent sharing of the crossing parents with similar genetic background with synergy effect of the inherited genetic difference between indica and japonica. A rice breeding strategy with the use of molecular markers was discussed for overcoming of genetic vulnerability owing to this genetic narrowness.