• Korean Journal of Breeding Science
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• v.43 no.1
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• pp.56-61
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• 2011

Brown planthopper(BPH) is one of the most destructive insect pests of rice. The use of genetically resistant cultivars has proven to be a more economical, efficient and environment friendly means to combat this pest. This study was carried out to investigate the relationship between BPH resistant gene, Bph18 and yield components of rice using DH(doubled haploid) lines derived from 'Saenuri'/SR30071-3-7-23-6-1-1-1. SR30071-3-7-23-6-1-1-1 line has Bph18 gene derived from wild species, Oryza australiensis. BPH resistant gene, Bph18 shortened heading days, enlarged culm length and panicle length and reduced ratio of ripened grains of rice. The results indicate that backcrossing breeding is necessary to develop elite cultivars carrying Bph18 gene.

• Food Science and Preservation
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• v.24 no.3
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• pp.334-342
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• 2017

The content of bioactive substances and antioxidative activity in conventionally grown brown rice (CGBR) and organically grown brown rice (OGBR) were compared. Minerals (mg/100 g) such as magnesium (OGBR, $168.59{\pm}2.62$; CGBR, $121.43{\pm}2.22$), copper (OGBR, $0.50{\pm}0.06$; CGBR, $0.41{\pm}0.05$), and manganese (OGBR, $4.70{\pm}0.04$; CGBR, $2.49{\pm}0.02$) were higher in OGBR than in CGBR (p<0.05). In addition, levels of (${\mu}g/100g$) vitamins B2 (OGBR, $27.22{\pm}2.56$; CGBR, $22.12{\pm}2.24$) and B6 (OGBR, $46.32{\pm}2.66$; CGBR, $39.91{\pm}3.32$) were higher in OGBR than in CGBR (p<0.05). The contents (mg/100 g) of ${\beta}$-sitosterol (OGBR, $27.40{\pm}2.79$; CGBR, $24.75{\pm}1.06$), total phenolic (OGBR, $6.72{\pm}0.02$; CGBR, $6.64{\pm}0.02$), and ferulic acid (OGBR, $1.75{\pm}0.45$; CGBR, $1.11{\pm}0.14$) as well as the antioxidative activity (OGBR, $53.09{\pm}1.90%$; CGBR, $48.29{\pm}3.38%$) evaluated using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging assay were higher in OGBR than in CGBR, although no significant differences between samples were observed. In comparison to the control group, brown rice samples significantly inhibited cholesteryl ester hydroperoxide formation in rat plasma subjected to copper ion-induced lipid peroxidation. The inhibitory effect of OGBR was higher than that of CGBR. These results indicate that OGBR showed higher levels of bioactive substances and enhanced antioxidative activity than CGBR, although the differences were not statistically significant.

• Korean Journal of Soil Science and Fertilizer
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• v.31 no.1
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• pp.51-55
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• 1998

The experiment was conducted to elucidate the growth response of rice seedling to heavy metals, copper and zinc. The copper and zinc concentration in rice seedling was 50mg/l and 100mg/l, respectively. Germination. chlorophyll and organic compounds were investigated in seedling of rice with or without heavy metals. Root growth and germination were inhibited at 50mg/l Cu and at 100mg/l compared to control and such reduction in growth was more remarkable at 100mg/l Zn than at 50mg/l Cu. Chlorophyll content was slightly reduced at both 50mg/l Cu and 100mg/l Zn. Malic acid was remarkably increased at 50mg/l Cu compared with that at Zn 100mg/l regardless of rice cultivars. The content of organic acids such as succinic, citric, and malic acid and free proline was increased with treatment of copper and zinc.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.5
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• pp.397-403
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• 2015

Heavy metals reduce the photosynthetic efficiency and disrupt metabolic reactions in a concentration-dependent manner. Moreover, by replacing the metal ions in metalloproteins that use essential metal ions, such as Cu, Zn, Mn, and Fe, as co-factors, heavy metals ultimately lead to the formation of reactive oxygen species (ROS). These, in turn, cause destruction of the cell membrane through lipid peroxidation, and eventually cause the plant to necrosis. Given the aforementioned factors, this study was aimed to understand the physiological responses of rice to cadmium (Cd) and arsenic (As) toxicity and the effect of essential metal ions on homeostasis. In order to confirm the level of physiological inhibition caused by heavy metal toxicity, hydroponically grown rice (Oryza sativa L. cv. Dongjin) plants were exposed with $0-50{\mu}M$ cadmium (Cd, $CdCl_2$) and arsenic (As, $NaAsO_2$) at 3-leaf stage, and then investigated malondialdehyde (MDA) contents after 7 days of the treatment. With increasing concentrations of Cd and As, the MDA content in leaf blade and root increased with a consistent trend. At 14 days after treatment with $30{\mu}M$ Cd and As, plant height showed no significant difference between Cd and As, with an identical reduction. However, As caused a greater decline than Cd for shoot fresh weight, dry weight, and water content. The largest amounts of Cd and As were found in the roots and also observed a large amount of transport to the leaf sheath. Interestingly, in terms of Cd transfer to the shoot parts of the plant, it was only transported to upper leaf blades, and we did not detect any Cd in lower leaf blades. However, As was transferred to a greater level in lower leaf blades than in upper leaf blades. In the roots, Cd inhibited Zn absorption, while As inhibited Cu uptake. Furthermore, in the leaf sheath, while Cd and As treatments caused no change in Cu homeostasis, they had an antagonist effect on the absorption of Zn. Finally, in both upper and lower leaf blades, Cd and As toxicity was found to inhibit absorption of both Cu and Zn. Based on these results, it would be considered that heavy metal toxicity causes an increase in lipid peroxidation. This, in turn, leads to damage to the conductive tissue connecting the roots, leaf sheath, and leaf blades, which results in a reduction in water content and causes several physiological alterations. Furthermore, by disrupting homeostasis of the essential metal ions, Cu and Zn, this causes complete heavy metal toxicity.

• Korean Journal of Breeding Science
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• v.49 no.3
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• pp.280-284
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• 2017

'Hwaweon 6' was developed from a cross between 'Hwaseongbyeo' and a wild species, Oryza minuta L. (Acc. No. 101154) based on marker-assisted selection and backcrossing. The recurrent parent 'Hwaseongbyeo' is a high grain quality cultivar with medium maturity. Hwaweon 6 is nearly isogenic to Hwaseongbyeo except a small O. minuta introgressed segment on chromosome 7 harboring genes related with spikelets per panicle. The preliminary and replicated yield trial was conducted at Chungnam National University and Chungcheongnamdo Agricultural Research & Extension (CARES), Yesan in 2009 and 2010. The local adaptability test was carried out by the National Seed Management Office (NSMO) in 2011 and 2012. This cultivar was registered to NSMO with a cultivar designated as Hwaweon 6. This cultivar averaged 80cm in culm length and has a medium growth duration. Milled rice of Hwaweon 6 is translucent and the grain quality traits are comparable to those of the recurrent parent. The average yield potential of Hwaweon 6 in grain was about 6.57 MT/ha at the ordinary fertilizer level for two years about 3.0% higher than that of Hwaseongbyeo due to an introgression of the quantitative trait locus (QTL) for spikelets per panicle (qSPP7) from O. minuta. This variety is comparable to Hwaseongbyeo in low temperature germinability and cold tolerance. The qSPP7 QTL would be useful in enhancing yield potential in rice breeding program.

• Korean Journal of Breeding Science
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• v.42 no.5
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• pp.463-469
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• 2010

Rice is a staple food for more than 50% of the world's population. Embryo comprises only 2 to 3% of the weight distribution of the entire pericarp but has higher concentration of vitamins, proteins, and essential fatty acids than the other parts of grains. Moreover, ${\alpha}$-tocoperol, ${\gamma}$-oryzanol, phytic acid and ${\gamma}$-aminobutric acid that have nutraceutical value are abundant. Increasing the volume of embryo assures the fortification of nutritional value of rice grain. We developed new black waxy giant embryo rice, Milyang 263 by crossing Josaengheugchal, a black waxy rice variety, and $ge^t$, a giant embryo mutant generated by tissue culture. The nutrient contents and physical properties of Milyang 263 were compared with several giant embryo mutants and normal embryo rice varieties. Changes in the nutrient properties after germination were also observed. Results indicated that this new black waxy giant embryo rice, Milyang 263, offers a promising source for improving nutritional quality of rice especially anthocyanin, essential minerals, and GABA.

• Korean Journal of Breeding Science
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• v.42 no.4
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• pp.413-418
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• 2010

A total of 424 plants was regenerated from the seed-culture of a rice cultivar, 'Ilpum'. The regenerated plants were grown in a greenhouse. The 297 plants with high fertility were selected among 424 plants. The harvested seeds from each plant were planted to each line at experiment field in 2008 and 2009. The each line was evaluated for the agronomic and morphological traits, also. The 64 lines (21.5%) showed significant differences in agronomic and morphological traits from donor cultivar 'Ilpum' among 297 lines. The heading date different from donor cultivar 'Ilpum' showed highest frequency in 297 lines, and accounts for 9.1% (29 lines). The phenotype of opaque endosperm and rolling leaf account for 1.7% and 1.3% in 297 lines, respectively. The genetic segregation was observed in dwarf/semi-dwarf, rolling leaf and opaque endosperm at $S_1$ generation, but not in $S_2$ generation. These results suggest that the mutant derived from a tissue-culture will be one of the promising genetic resources, due to its wide variation and high frequency of mutation, comparatively.

• Korean Journal of Breeding Science
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• v.43 no.5
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• pp.464-469
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• 2011

Virus diseases often cause serious damage to rice production in Asia. The lack of information on virus resistance genes has been a major obstacle for the breeding of resistant varieties. In order to identify DNA marker associated with resistance against rice stripe virus (RSV), the quantitative trait locus (QTL) was carried out using advanced backcross population developed from a cross between RSV-resistant tongil type cultivar Shinkwang and susceptible japonica cultivar Ilpum. A RSV resistance QTL $qSTV11^{SG}$ explaining 44.2% of the phenotypic variation was identified on chromosome 11 of Tongil type rice cultivar 'Shingwang'. $qSTV11^{SG}$ was tightly linked to DNA marker RM6897. The RM6897 divided as resistance type allele and susceptible type alleles. Twenty seven resistant varieties showed the resistant-type allele and 23 susceptible varieties were susceptible-type allele to the marker of RM6897. This results and the molecular markers presented here may be useful in rice breeding for improving RSV resistance in japonica rice.

• Korean Journal of Breeding Science
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• v.43 no.4
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• pp.304-310
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• 2011

In previous studies, we reported QTLs for grain weight (GW), qGW3 and for spikelets per panicle (SPP), qSPP3 linked to RM60 on chromosome 3 using advanced backcross lines derived from a cross between Oryza sativa ssp. Indica cv. Milyang 23 and O. glaberrima. The O. glaberrima alleles at this locus increased GW and spikelets per panicle in the Milyang 23 background. To further confirm and narrow down the position of the QTLs on chromosome 3, substitution mapping was performed using five lines containing the target O. glaberrima segment on chromosome 3. The size and position of the O. glaberrima segment on chromosome 3 were different in each line. These lines possessed 3-10 non-target O. glaberrima introgressions in the Milyang 23 background. These five lines were evaluated for seven agronomic traits including 1,000 grain weight and spikelets per panicle and also genotyped with seven SSR markers. Four lines were informative in delimiting the position of QTLs, qGW3 and qSPP3. Two lines with the O. glaberrima segment flanked by SSR markers, RM60 and RM523 displayed significantly higher values than Milyang 23 in GW and SPP whereas two lines without that O. glaberrima segment displayed no difference in GW and SPP compared to Milyang 23. The result indicates that two QTL, qGW3 and qSPP3 are located in the interval between RM60 and RM523 which are 1.2-Mb apart. Introgression lines having QTLs, qGW3 and qSPP3 would be useful materials not only to indentify the relationship between these two yield QTLs, but also to develop high yielding variety via marker-aided selection technology.

• Korean Journal of Organic Agriculture
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• v.26 no.4
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• pp.629-647
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• 2018

This study was carried out to investigate the economic value of organic rice production using gelatin chitin microorganisms in eco-friendly complex, Gongsan, Naju city. The soil condition of experiment paddy field was Jeonbuk series and silt loam with a slightly poor drainage. Except for the high effective silicate, the chemical characteristics of soils used were included in the optimum range of paddy soils in Korea. In growth, plant length, tiller number, ear number, and ear length were observed to be higher in conventional paddy fields than organic paddy fields. However, number of grain per panicle and grain filling ratio (%) were higher in organic paddy fields than conventional paddy fields. Incidences of diseases and insect pests were slightly higher in the organic paddy fields. Water weevil, sheath blight, rice leaf roller and rice blast were more occurred in organic paddy field. On the other hand, false smut was higher occurred in conventional paddy field. There was a significant negative correlation between rice sheath blight and rice leaf roller, and rice yield. In the milled rice quality, the quality of organically cultivated milled rices was lower by the increase of broken rice than that of conventionally cultivated milled rices. The quality and palatability of rice were higher in organic cultivation with decreasing of protein content. Net income of conventionally and organically cultivated rice was 360,000 won/10a and 610,000 won/10a, respectively. Premium net income of the organically cultivated rice was 68%.