• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.3
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• pp.224-231
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• 2003

This study was conducted to investigate the varietal differences in leaf senescence during ripening stage and its relation to grain yield of rice. During grain filling period leaf senescence was evaluated by SPAD readings (an indirect indicator of chlorophyll content) for 74 varieties including local, improved domestic, and introduced varieties in the field condition. Leaf senescence was varied greatly among 74 varieties. Jodongji and Dadajo known as local rice varieties had significantly lower SPAD value than the other varieties and became senescent rapidly. However, SPAD value of the flag leaf and 2nd leaf of SNU-SG1 were much higher than the other varieties and leaves of SNU-SG1 also showed a tendency of delayed senescence compared to the other varieties. There were significantly positive correlation between cumulated SPAD value of upper leaf(flag leaf and 2nd leaf) during 35 days after heading and grain yield divided by sunshine hour during 40 days of grain filling and compensated for temperature effect, and cumulated SPAD value of the 4th leaf showed negative correlation with the yield. That is, the delayed senescence of the upper leaves and the rapid senescence of lower leaves were positively associated with grain yield increase.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.spc1
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• pp.67-72
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• 2006

This experiment was carried out to identify rice varieties suitable for growing under low N-fertilization levels. Eighteen rice varieties were grown at 5.5 kg and 11 kg/10a nitrogen levels in 2004-2005 in Taegu, Korea. Several varieties like Ilmibyeo, Nampyeongbyeo, Sindongjinbyeo, Dongjin 1 and Donganbyeo yielded more than 470 kg/10a. Low N-fertilization level (5.5 kg/10a) decreased yields of Junambyeo and Donganbyeo by more than 10%. However, the decrease in yield was not significant in Surabyeo and Hwayeongbyeo compared with the 11 kg/10a N-fertilizer treatment. Improved grain quality, chemical properties and palatability was noted in some rice varieties. In terms of rice yield and grain quality, Donganbyeo, Ilmibyeo, Ilpumbyeo, Dongjin 1, Saechoocheongbyeo and Saegyehwabyeo were selected as premising rice varieties for growing under low N-fertilization levels.

• Korean Journal of Plant Resources
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• v.11 no.3
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• pp.257-263
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• 1998

Fifteen varieties of Oryza sativa mainly includig those of Korean native rice were exactly cutted into three layers such as L$_1$ layer (the outer part of 90% from rice center), L$_2$ layer(the part of 81 ~ 91% from the rice center) and L$_3$ layer(the inner part of 80% from the rice center) and ferulic acid derivatives, which play an important role of antioxidative action, were quantitiavely analyzed by UV absorption spectrometric method at fixed 314nm. From this experiment, it was found that the more it enters from the surface into the rice center, the more those secondary metabolites contents were highly reduced. The varieties showing contents more than 20 mg/g were as follows: Hwasunchalbyeo(25.8mg/g), Jojeongdo(24.1mg/g), Suwon425(21.2mg/g), Daigolbyeo(20.6mg/g) and Nonglimna 1(20.2mg/g) by this order. Estimation onthe anthocyanin contents of both Suwon 425 and Sanghehanghyeolna revealed that its total. contents were very exactly close each other. However, it was charateristically differentiated in the contents of L$_2$ layer with respect to showing a considerably higher content of Suwon 425 than of Sanghaehanghyeolna. Conclusively, the selected Suwon 425 variety, which is coloured and flavour volatile one, showed relatively higher contents of anthocyanin, ferulic acid derivatives in the L$_2$ layer as well as L$_1$ layer when compared with Sanghaehangyeolna and even other varieties. This fact suggested that Suwon 425 could be a promising candidate for the development of health rice food.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.2
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• pp.183-192
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• 2004

The effect of eight varieties of grain and forage type whole crop rice (Oryza sativa L Japonica) each harvested at four stages of maturity were investigated for morphology and yield, proportion of botanical fractions, fermentatability and chemical composition in an $8{\times}4$ factorial experiment. All crops were sown in 1997 at Saitama Prefecture, Japan under identical condition and harvested on 10, 22, 34 and 45 days after flowering in 1998. Total DM yield of forage type varieties was similar to that of the highest yield of grain type varieties. However, while yield of forage type varieties was attributed to higher proportion of straw than head, the reverse was in the case of grain type varieties. Yield in line with the proportion of head increased (p<0.001), but in contrast proportion of straw decreased (p<0.001) with the increase in maturity. Silage fermentability of grain type varieties was better than forage type varieties. Fermentability improved with the increase (p<0.001) in maturity suggesting that the moisture content should be reduced to improve fermentation quality. Forage type varieties contained higher (p<0.001) ash, crude fat (EE), organic cell wall (OCW) and acid detergent fiber (ADF), but contained lower crude protein (CP), organic cell content (OCC), CP in OCC and nitrogen-free cell wall extract (NCWFE) than the grain type varieties. The ash, CP, EE, Oa (60% digestible OCW), Ob (40% digestible OCW), OCW, ADF and acid detergent lignin (ADL) decreased (p<0.001), but OCC and NCWFE increased (p<0.001) with the increase in maturity. It is concluded that stage of maturity not only increases yield and proportion of head, but also improved the fermentation quality and increases quality chemical composition (except CP) of whole crop rice. Forage type varieties may be as good as grain type varieties in terms of yield, but fermentation quality and chemical composition may not be as good as that of grain type varieties.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.3
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• pp.357-366
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• 1997

Rice quality is considered to have two general meanings; 1) milling, cooking, and processing quality, which refer to suitability of the grain for a particular end-use; and 2) physical quality, which means cleanliness, soundness, and freedom from foreign materials. Grain type is associated with specific milling, cooking, and processing characteristics. Thus, this experiment was conducted to classify the grain type categories and marketing grades for Korean leading rice varieties. Length: width ratio of brown rice kernel ranged from 1.57 to 2.25 and most of varieties belonged to short grain except Tongil type rice varieties. Mean of length: width ratio of brown rice kernel was 1.77 and coefficient of variance was 4.79％ in short grain type varieties. Grain shape could be further classified into 5 types by length:width ratio of brown rice kernel; 1 type(less than 1.75), 2 type(1.76∼1.80), 3 type(1.81∼1.90), 4 type(1.91∼2.00), and 5 type (greater than 2.00). For 1 and 2 type of varieties, woven wire sieve having 1.7mm openings showed better whole-kernel yields for special marketing grade, and sieve having 2.0mm openings for 3 and 4 type of varieties. Grain type which classified into 5 categories was not associated with physicochemical and cooking characteristics of rice grain, but sensory evaluation of cooked rice showed better score for 1 type varieties in terms of appearance, gloss, flavor, texture, stickiness, and taste.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.1
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• pp.113-119
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• 1995

This excperiment was conducted to investigate relation on seed dormancy and vi-viparous germination with sucrose content, fatty acid composition and abscisic acid content of rice seeds. The following results were obtained by this experiment. Sucrose content of brown rice harvested at 20 and 40 days after heading was higher in Japonica and Sare type varieties than in Tongil and Indica type rices. Positive relationship was found be-tween sucrose content of brown rice and viviparous germination rate of rice varieties tested.J aponica and Sare type rice varieties showed low proportion of oleic acid and higher proportion of linoleic acid in brown rice harvested at 20 and 40 days after heading than Tongil and Indica rices tested. Viviparous germination was negatively correlated with the proportion oleic acid and positively with that of linoleic acid. Abscisic acid content in hull of rice seeds stored for 30 days at 25/15$^{\circ}C$ fluctuation temperature condition was decreased more rapidly than 4$^{\circ}C$, and Japonica varieties tested showed lower con-tent of abscisic acid in rice hull than Tongil and Indica varieties used.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.1
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• pp.191-198
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• 1999

Fifteen varieties of Oryza sativa mainly including those of Korean native rice were exactly cutted into three layers such as L1 layer(the outer part of 92% from rice center), L2 layer(the part of 81∼91% from the rice center) and L3 layer(the inner part of 80% from the rice center) We biologically evaluated the antioxidative effect on the every layer(L1, L2 and L3) of all the varieties, by observing malondialdehyde (MDA) produced by galactosamine in the mouse. L1 layer of some varieties showed significant antiox idative effect, while L2 and L3 layer didn't show the activity. It was also suggested that coloured rice(Suwon 425 and Sanggaehangbyeolna) showed stronger activity than other general rices, probably due to high contents of anthocyanins. Successively, we evaluated antihepatotoxic effect, based on the determination of serum ALT and AST activity. Some varieties of only L1 layer, except for L2 and L3 layer, significantly decreased the serum ALT and AST activity. This finding indicate that oral diet of some raw rice are able to protect hepatotoxicities. Among all the samples tested, L1 layer of Suwon 425 showed the strongest antihepatotoxic effect. From quantitative analysis on ferulic acid derivatives, it was found that the more it enters from the surface into the rice center, the more those secondary metabolites contents were highly reduced. These findings above suggested that Suwon 425 could be a promising candidate for the development of health rice food.

• Journal of the Korean Geographical Society
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• v.38 no.1
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• pp.48-69
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• 2003

Colonialism heretofore described merely as a political economic phenomenon denotes another aspect, namely, an ecological imperialism that accompanies the biological implantation of human beings, crops, weeds, domestic animals, and pathogens onto colonized lands. Foremost, the Korean Peninsula during the colonial period served as a testing ground for the transplanted Japanese varieties of rice. Near the mid-1940s, the new varieties came to dominate over 90% of cultivated rice paddy. The speedy diffusion of transplanted rice was attributable to the aggressive promotion of agricultural institutions led by the Institute of Agricultural Tests and Experiments. Various policies and tactics were also instrumental to the nationwide distribution of new varieties, and they included naming recommended varieties, sponsoring rice contests, establishing crop inspection offices, educating young farmers at training camps, and publishing newsletters for agricultural societies. The forward and backward linkages that came along with the new varieties of transplanted rice helped to consolidate colonial status quo and to create hybrid agricultural landscapes in the Korean countryside.

• Journal of Crop Science and Biotechnology
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• v.11 no.3
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• pp.205-214
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• 2008

Blast disease caused by the fungal pathogen, Magnaporthe oryzae, is one of the most damaging diseases in rice. The use of resistant varieties is an effective measure to control the disease, however, many resistant varieties were broken down to their resistance effects by the differentiating of new virulent isolates. This study was done to analyze the haplotypes of 31 microsatellite markers linked to five major R genes and two QTLs and to identify the alleles for the putatively novel genes related to durable resistance to blast in 56 Korean japonica and four indica varieties. The 31 microsatellite markers produced 2 to 13 alleles(mean = 5.4) and had PICi values ranging from 0.065 to 0.860(mean=0.563) among the 60 rice accessions. Cluster analysis based on allele diversities of 31 microsatellite markers grouped into 60 haplotypes and ten major clusters in 0.810 genetic similarity. A subcluster IV-1 grouped of early flowering varieties harboring Piz and/or Pi9(t) on chromosome 6 and Pita/Pita-2 gene on chromosome 12. The other subcluster V-1 consisted of four stable resistance varieties Donghae, Seomjin, Palgong and Milyang20. The analysis of putative QTLs associated with seven blast resistance genes using ANOVA and linear regression showed high significance to blast resistance across regions and isolates in the markers of two genes Piz and/or Pi9(t) and Pita/Pita-2. These results illustrate the utility of microsatellite markers to identify rice varieties is likely carrying the same R genes and QTLs and rice lines with potentially novel resistant gene.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.3
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• pp.261-272
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• 2008

This study was conducted to provide the fundamental data based on the agronomic characteristics of domestic aroma rice, widely cultivated domestic rice and foreign aroma rice for breeding of functional aromatic rice. Among the 104 varieties, all of domestic aroma rice and widely cultivated rice varieties were headed, 24 of 84 varieties of foreign aroma rice were not headed. The average heading date of domestic aroma rice Japonica types of domestic rice was later as 136 day, and Tongil types of domestic aroma rice were faster as 122 day. The average culm length of Indica types of foreign aroma rice was longer as 130 cm, and Tongil types of were shorter as 74 cm. The average panicle length of domestic aroma rice and traditional rice were about 21 cm, and Indica types of foreign aroma rice were longer as 29.5 cm. The average 1,000 grain weight of Tongil types of domestic aroma rice and was not a difference with the domestic aroma rice and was more 2.5 g than the Indica types of foreign aroma rice. The average ratio of grain width and length of Indica types of foreign aroma rice were highest as 3.29 (W/L), and the domestic traditional rice was lowest as 1.7 (W/L). The average fertility rate of the domestic aroma rice, the widely cultivated domestic rice, and the Japonica types of foreign aroma rice were above 89.7%, but the Indica types of foreign and the Tongil types of domestic aroma rice were below 65.4%. The average germination rate of foreign aroma rice were above 83.7%, and domestic aroma rice were above 90.4%. The non-glutinous rice were 64 varieties (84.2%) of total 104 accessions of material rice and the waxy rice were 7 varieties (1%). In the domestic aroma rice, Hyangmi2ho and Aranghyangchalbyeo has a mild aroma grade. In the foreign aroma rice, 22 of 40 varieties of Indica types and 9 of 16 varieties of Japonica types has a lightly aroma grade. And 13 varieties of widely cultivated domestic rice has a non-aroma grade.