• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.98-98
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• 2017

Leaf senescence is the process of aging in plants. Chlorophyll degradation during leaf senescence has the important role translocating nutrients from leaves to storage organs. The functional stay-green with slow leaf yellowing and photosynthesis activity maintenance has been considered one of strategy for increasing crop productivity. Here, we have identified two QTLs on chromosome 9 and 10 for leaf senescence with chlorophyll content of RIL population derived from a cross between Hanareum 2, early leaf senescence Indica-type variety, and Unkwang, delayed leaf senescence Japonica variety. Among these QTLs, we chose qPLS1 QTL on chromosome 9 for further study. qPLS1 was found to explain 14.4% of the total phenotypic variation with 11.2 of LOD score. Through fine-mapping approach, qPLS1 QTL locus was narrowed down to about 25kb in the marker interval between In/del-4-7-9 and In/del-5-9-4. There are 3 genes existed within 25kb of qPLS1 locus: LOC_Os09g36200, LOC_Os09g36210, and LOC_Os09g36220. Among these genes, transcript level of LOC_Os09g36200 was increased during the leaf senescence stage and the expression level of LOC_Os09g36200 in Indica was higher than in Japonica. Finally, we chose LOC_Os09g36200 as candidate gene and renamed it as OsPLS1-In and OsPLS1-Jp from Indica- and Japonica-type rice, respectively. OsPLS1-In and OsPLS1-Jp overexpressing transgenic plants showed both early leaf senescence phenotype. These results indicate that OsPLS1 functions in chlorophyll degradation and the difference of expression level of OsPLS1 cause the difference of leaf senescence between Indica and Japonica in rice.

• Korean Journal of Agricultural Science
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• v.16 no.1
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• pp.1-18
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• 1989

This experiment was undertaken to clarify derivation of resistance of Japonica type of rice varieties to rice blast in Korea and to classify Japonica type of rice varieties on the basis of their rice blast reaction in the blast nuisery test. 1. The resistance of Iljin, Kwancheok 9, Koshi, Baedal and Paldal, Jaekeon, Sinpung, Jinheung, Hokwang and Palkeum, and Gwangmyungbyeo and Yeongdeogbyeo to rice blast was derived from Kyudai Taicho Asahi 3, Futaba and 2067, respectively. 2. The resistance of Kwanok, Mankyeong and Nongbaek to the rice blast was derived from Kanto 55, Hokwang and Kusabue, and Ishigarisiroge, respectively. 3. The resistance of Seomjinbyeo, Sinseonchalbyeo, Donghaebyeo and Tamjinbyeo to the rice blast was derived from Milyang 20 and the source of resistance to the rice blast in Jinjubyeo and Daecheongbyeo was HR 769 or HR 1590. 4. The resistance of Dobongbyeo, Gwanagbyeo and Chiagbyeo to the rice blast was derived from Tjina, Kongo and Kuik 90, respectively. 5. The resistance of Seolagbyeo, Seonambyeo, Kihobyeo, Namyangbyeo, Samnambyeo, Seohaebyeo, Whaseongbyeo, Daegwanbyeo and Taeseongbyeo, and Sobaegbyeo, Odaebyeo and Unbongbyeo to the rice blast was derived from Fuji 280 and Fuji 269, respectively. 6. The source of resistance to the rice blast in Cheonmabyeo and Baegambyeo was BL 7 and Nongbaek, the resistance of Dongjinbyeo and Sangpungbyeo to the rice blast was derived from Satominori and Simokita, respectively. 7. Japonica type of rice varieties was classified into eleven varietal groups according to their reaction to the blast as follows. Eight varieties of Jinheung group, two varieties of Dongjinbyeo group, two varieties of Jinjubyeo group, three varieties of Gwanagbyeo group, four varieties of Sobaegbyeo group, one variety of Nongbaek group, two varieties of Baegambyeo group, five varieties of Sinseonchalbyeo group, five varieties of Seonambyeo group, two varieties of Taeseongbyeo group and some variety of Nagdongbyeo group.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.23 no.1
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• pp.81-85
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• 1978

Competitive ability was determined for two different varieties, Josaengtongil (early maturing indicajaponica type) and Jinheung (medium maturing japonica type), against Cyperus serotinus(nut sedge). An increase of rice density increased competitive ability of rice to C. serotinus. The results indicate that the use of tall and medium maturingvariety like Jinheung provides better competitive ability against C. serotinus than Josaengtongil, a semi-dwarf and early maturing type.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2005.11a
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• pp.95-105
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• 2005

Transposon-mediated insertional mutagenesis provides one of the most powerful tools for functional studies of genes in higher plants. This project has been performed to develop a large population of insertional mutations, and to construct databases of molecular information on Ds insertion sites in rice. Ultimate goals are to supply genetic materials and information to analyze gene function and to identify and utilize agronomically important genes for breeding purpose. Two strategies have been employed to generate the large scale of transposon population in a Japonica type rice, Dongjin Byeo; 1) genetic crosses between Ac and Ds lines and 2) plant regeneration from seeds carrying Ac and Ds. Our study showed that over 70% of regenerated plants generally carried independent Ds elements and high activity of transposition was detected only during regeneration period. Ds-flanking DNA amplified from leaf tissues of F2 and T1 (or T2) plants have been amplified via TAIL-PCR and directly sequenced. So far, over 65,000 Ds lines have been generated and over 9,500 Ds loci have been mapped on chromosomes by sequence analysis. Database of molecular information on Ds insertion sites has been constructed, and has been opened to the public and will be updated soon at http://www.niab.go.kr. Detailed functional analysis of more than 30 rice mutants has been performed. Several Ds-tagged rice genes that have been selected for functional analysis will be briefly introduced. We expect that a great deal of information and genetic resources of Ds lines would be obtained during the course of this project, which will be shared with domestic and international rice researchers. In addition to the Japonica rice, we have established the tagging system in an rice line of indica genetic background, MGRI079. MGRI079 (Indica/Japonica) was transformed with Agrobacteria carrying Ac and Ds T-DNA vectors. Among transgenic lines, we successfully identified single-copy Ds and Ac lines in MGR1079. These lines were served as ‘starter lines’ to mutagenize Indica genetic background. To achieve rapid, large scale generation of Ds transposant lines, MGR1079 transformants carrying homozygous Ac were crossed with ones with homozygous Ds, and $F_2$seeds were used for plant regeneration. In this year, over 2,000 regeneration plants were grown in the field. We are able to evaluate the tagging efficiency in the Indica genetic background in the fall.

• Journal of the Korean Society of Food Science and Nutrition
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• v.16 no.2
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• pp.69-74
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• 1987

The effects of soaking temperature on hydration and cooking rates of Chunmabyeo(Japonica) and Kayabyeo(J/Indica) rice were investigated. Water uptake and volume increase rates of milled rice were increased as a function of soaking temperature$(4^{\circ}C{\sim}30^{\circ}C)$. The rate of volume increase of milled rice was greater than that of weight increase, which was more pronounced at low soaking temperature. The soaking of milled rice prior to cooking had a definite effect on the degree of gelatinization. The soaked milled rice was more easily gelatinized than unseated one. The water uptake rate, volume increase rate, degree of gelatinization and cooking rate of milled rice were faster in Kayabyeo than Chunmabyeo.

• Molecules and Cells
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• v.37 no.2
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• pp.149-160
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• 2014

Plant breeders have focused on improving plant architecture as an effective means to increase crop yield. Here, we identify the main-effect quantitative trait loci (QTLs) for plant shape-related traits in rice (Oryza sativa) and find candidate genes by applying whole genome re-sequencing of two parental cultivars using next-generation sequencing. To identify QTLs influencing plant shape, we analyzed six traits: plant height, tiller number, panicle diameter, panicle length, flag leaf length, and flag leaf width. We performed QTL analysis with 178 $F_7$ recombinant inbred lines (RILs) from a cross of japonica rice line 'SNU-SG1' and indica rice line 'Milyang23'. Using 131 molecular markers, including 28 insertion/deletion markers, we identified 11 main- and 16 minor-effect QTLs for the six traits with a threshold LOD value > 2.8. Our sequence analysis identified fifty-four candidate genes for the main-effect QTLs. By further comparison of coding sequences and meta-expression profiles between japonica and indica rice varieties, we finally chose 15 strong candidate genes for the 11 main-effect QTLs. Our study shows that the whole-genome sequence data substantially enhanced the efficiency of polymorphic marker development for QTL fine-mapping and the identification of possible candidate genes. This yields useful genetic resources for breeding high-yielding rice cultivars with improved plant architecture.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.354-354
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• 2017

Rice grain yield is determined by crop dry matter production that is sensitive to temperature. Our objective was to determine whether the difference in temperature between years had an impact on the relationship between yield components and grain yield. Field experiments were conducted under machine transplanting cultivation by using yield data of two japonica rice varieties, Odaebyeo (early maturing) and Nampyeong (mid-late maturing), in 2013 to 2016 in Suwon, Korea. Plant height, dry weight, and yield components were examined by analysis of variance, correlation. The milled rice yield of the two varieties were the highest in 2016, however the lowest yields were observed in the different years. In 2016, Odaebyeo produced $0.96t\;ha^{-1}$ greater milled rice yield than in 2015, and Nampyeong produced $1.11t\;ha^{-1}$ greater yield than in 2013. The correlation analysis indicated that spikelet per panicle (R = 0.53) was associated with grain yield of Odaebyeo. In Nampyeong, biomass at heading date (R = 0.74), 1000-grain weight (R = 0.71), spikelet per panicle (R = 0.58), and panicle number per $m^2$ were associated with grain yield. Sink size (spikelet number per $m^2$) of the two varieties responded to accumulative temperature from transplanting to panicle initiation stage. In this experiment, optimal accumulative temperature before panicle initiation has effect on increased spikelet number and/or number of panicle that were mainly responsible for yield difference. Rice production research to increase grain yield should consider all yield components, but increased emphasis on biomass production before heading is also necessary as well as grain ripening conditions.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.6
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• pp.565-570
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• 2006

The viviparous germination (VG) with lodging caused the yield reduction and quality deterioration in rice. We carried out the evaluation of VG tolerance (on the 40th day after heading) and mapping QTLs associated with VG tolerance using the recombinant inbred lines (M/G RILs) from a cross between Milyang 23 (japonica/indica) and Gihobyeo (japonica). The VG rates of Milyang 23 and Gihobyeo were 0.0 and 7.0%, respectively. The averaged VG rate of 162 M/G RILs was 7.7%, and their range was from 0.0 to 50.9%. Of the 162 RILs, 144 lines were tolerant less than 10%, and 18 lines were susceptible more than 10%. Using the M/G RIL Map, three QTLs associated with the viviparous trait were detected on chromosome 2 (qVG 2-1 and qVG 2-2) and 8 (qVG 8). qVG 2-1 was linked to RM 32D and RZ 166, and had LOD score of 2.97. qVG 2-2 was tightly linked to E13M59.119-Pl and E13M59.M003-P2, and showed higher LOD score of 3.41. qVG 8 was linked to RM33 and TCT116, and had LOD score of 2.67. The total phenotypic variance explained by the three QTLs was about 24.4% of the total variance in the population. The detection of new QTLs associated with VG tolerance will provide important informations for the seed dormancy, low temperature germination, or comparative genetics.

• Korean journal of applied entomology
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• v.15 no.2 s.27
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• pp.89-93
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• 1976

The present report is dealt with the spiders which are caught within a space of $1m^2$ of rice paddy field where was harvested the rice crops in Jeonbug district, from November 4 to 11, to 1975. 1. Twenty-one species of spiders were caught at the area during the period. Of these the dominant species were Gnathonarium dentatum, Pirate subpiraticus, Gnathonarium gibberum, Oedothorax insecticeps etc. 2. Average density of spiders within a space of $1m^2$ of rice paddy field where rice crops was harvested was as follows: 125 at Iri, 102 at Jinan, 133 at Buan, and 58 at Daejang. 3. The scientific names of spiders which were caught in rice paddy field for the first time in Korea were Gnathonarium gibberum, Enoplognatha japonica, Erigone prominens, Erigonidium graminicola, Theridion octomaculatum, Lycosa pseudoannulata, Dolomedes angustivirgatus. As the result of this survey, fifty-five species of spiders were recorded in rice paddy field of Korea.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.4
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• pp.434-439
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• 2008

The amount of salt to make seed sorting solution of the specific gravity of 1.13 was reconsidered and determined as 3.8 kg salt in 18 L water, which is lower amount than currently used. Five rice cultivars were examined. Percent germination and seedling emergence were not similar. Seedling emergence rate of Japonica varieties, Nampyungbyeo and Daerypbyeo-1 were 87% and 95% under specific gravity of 1.13, respectively. Seedling emergence rate of Tongil type variety, Dasanbyeo was as high as 67% in specific gravity of 1.06. Seedling emergence rate of waxy rice, Hwasunchalbyeo and Aranghangchalbyeo were examined. Seedling emergence rate was 94% in both cultivars in specific gravity of 1.04. Seedling emergence rate was same in specific gravity of 1.08 which is generally used for selecting seed currently. Early growth (plant height, leaf number, and dry weight) were not significantly different by specific gravity within species. In all cultivars except waxy rice, highest seedling emergence rate was observed in specific gravity of 1.13 which is currently used for selection and decreased as specific gravity is lowed. However, considering total amount of seeds in each group of specific gravity, amount of seed in lower specific gravity group is relatively small and total seedling emergence rate within variety dose not show big difference. However, if seeds with low speicific gravity are produced due to the bad grain filling condition and consequently total seed content of low specific gravity increases, results will be differnt. Reduction in total growth and yield could occur. It will be important to comply with the seed sorting criterion of 1.13 for Japonica, 1.06 for Tongil, and 1.04 for waxy rice variety to ensure the maximum rice growth and yield.