• Applied Biological Chemistry
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• v.15 no.1
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• pp.35-40
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• 1972

The contents of free amino acids in deembryod brown rice of two varieties were investigated by amino acid autoanalizer in relation to specific gravity grade. The analytical methods of free amino acid were also discussed. 1) The lower the specific gravity of the unhulled rice the higher the content of total free amino acids in the deembryod brown rice, and the similar trend appears to hold on each amino acids. 2) Main free amino acids were serine+asparagine, glutamic acid, aspartic acid, alanine and valine, and maximum values of them were 7.3, 5.1, 4.0, 3.4, 0.9mg/100g rice, respectively. They consist about 85% of total free amino acids in most cases. 3) The contents of soluble nitrogen and free amino acids appear to be lower in high protein variety (IR 667) than in low protein variety (Jinhung). The percentage of free amino acid nitrogen to soluble nitrogen, however, appears to be higher in high protein variety (IR 667). 4) Alanine was much lower than aspartic acid in IR 667 having Indica blood while alanine appears to be higher than aspartic acid in Jinhung (Japonica rice) suggesting varietal difference in amino acid metabolism. 5) Threonine peak was overlaped with glutamine, and serine was with asparagine in this study.

• Journal of Plant Biotechnology
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• v.44 no.4
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• pp.349-355
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• 2017

The amino acid composition of rice is a major concern of rice breeders because amino acids are among the most important nutrient components in rice. In this study, a genetic map was constructed with a population of 134 recombinant inbred lines (RILs) from a cross between Dasanbyeo (Tongil-type indica) and TR22183 (temperate japonica), as a means to detect the main and epistatic effect quantitative trait loci (QTLs) for the amino acid content (AAC). Using a linkage map which covered a total of 1458 cM based on 239 molecular marker loci, a total of six main-effect QTLs (M-QTLs) was identified for the content of six amino acids that were mapped onto chromosome 3. For all the M-QTLs, the TR22183 allele increased the trait values. The QTL cluster (flanked by id3015453 and id3016090) on chromosome 3 was associated with the content of five amino acids. The phenotypic variation, explained by the individual QTLs located in this cluster, ranged from 10.2 to 12.4%. In addition, 26 epistatic QTLs (Ep-QTLs) were detected and the 25 loci involved in this interaction were distributed on all nine chromosomes. Both the M-QTLs and Ep-QTLs detected in this study will be useful in breeding programs which target the development of rice with improved amino acid composition.

• Applied Biological Chemistry
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• v.27 no.3
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• pp.204-210
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• 1984

Hydration of twelve japonica (j) and nine j x indica rice varieties was analyzed in terms of mathematical rate equation and a tentative classification of milled rice was attempted primarily on the basis of water uptake race of rice grain at room temperature. No two rice varieties had the same water uptake rate or diffusion coefficient. The rice samples could be classified into three groups. Rices which are considered as having good eating quality had lower water uptake rate.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.633-636
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• 2007

The objective of this study is to measure backscattering coefficients of paddy rice using L, C, X-bands scatterometer system during a rice growth period. The measurement was conducted at an experimental field located in National Institute of Agricultural Science and Technology (NIAST), Suwon, Korea. The rice cultivar was a kind of Japonica type, called Chuchung. The scatterometer system consists of dual-polarimetric square horn antennas, HP8720D vector network analyzer (20MHz ${\sim}$ 20GHz), RF cables, and a personal computer that controls frequency, polarization and data storage. The scatterometer system is calibrated using a calibration kit (3.5mm, 85052D). The backscattering coefficients were calculated by applying radar equation for the measured at incidence angles between $20^{\circ}$ and $60^{\circ}$ for four polarization (HR, VV, HV, VH), respectively, and compared with rice growth data such as plant height, stem number, biomass, dry weight and LAI that were collected at time of each scatterometer measurement simultaneously.

• Applied Biological Chemistry
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• v.28 no.3
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• pp.142-148
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• 1985

Pasting properties of 35 traditional (Japonica) and 23 high-yielding (J/Indica) rice varieties having various hydration rates at $23^{\circ}C$ were investigated. Amylograms showed that high-yielding rice varieties had higher values for peak (P), hot-paste (H) and cold-paste (C) viscosities than those for traditional rice varieties. P had a highly negative correlation with H/P, C/P and C/H. P of traditional rice varieties was positively and negatively correlated with protein amylose contents, respectively. However, H and C showed no correlation with protein or amylose content. No correlation was observed between amylograph indices and hydration rate of rice grain.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.1
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• pp.45-54
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• 1994

Cooking characteristics of ninety five non-glutinous and twenty six glutinous varieties were checked for understanding the varietal variation and interrelationship between the cooking and physicochemical properties of rice grain. The greatest variation in non-glutinous and glutinous rice varieties was observed in iodine blue value and the next large variation was recognized in amount of soluble solid in cooking water. Average values of volume expansion rate, iodine blue value and amounts of soluble solid in cooking water were different among domestic-bred japonica, Korean local and foreign rice varieties. Korean-bred japonica rice cultivars can be classified into several groups having same cooking quality such as <Jangan.·Seoan>, <Jinmi·Ilpum· Daeseong>, <Seohae·Namwon·Yeongduk>, <Chucheong·Bongkwang>, <Odae·Keumo> and <Hwacheong·Donghae·Palgong> by the distribution on the plane of 1st and 2nd principal components contracted from four cooking characteristics. Glutinous rice cultivars can be grouped into several different cooking quality types such as <Nonglimna 1·Suwon 357·Jodo·Inbujinado>, <Sangnambatbyeo·Jeokdo>, <Mujudo·Daigol-mochi>, <Daegoldo·Jindo>, <Jinbuchal·Colored Daegoldo>, <Shinseonchal·Hung-Tsan> and <Agudo·Irakdo> by the same analysis. Positive correlation was found between volume expansion rate and water absorption rate at 21℃. Iodine blue value was correlated negatively with amounts of soluble solid, and positively with amylose content in non-glutinous rices. In glutinous rices volume expansion rate showed positive relationship with iodine blue value, amounts of soluble solid and gel consistency. Iodine blue value was also positively correlated with alkali digestion value in glutinous rice.

• Current Research on Agriculture and Life Sciences
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• v.27
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• pp.21-28
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• 2009

The purpose of this study was to improve the culturability of 'IR 36', a indica type rice cultivar using DNA marker associated with the ability of plant regeneration in anther and seed culture. The culturability of 6 rice cultivars and 2 indica/japonica lines ('MGRI 036', 'MGRI 079') were investigated in anther and seed culture. The culturability of 3 japonica rice cultivars were much higher than tongil and indica rice cultivars, and 'MGRI 036' and 'MGRI 079' has high culturability with 20% regenerability, also. 34 $BC_2F_4$ 4 lines were selected by marker screening using RZ400 among 90 $BC_2F_4$ lines derived from a cross between 'MGRI 079' and 'IR 36'. The frequency of callus formation of 10 $BC_2F_4$ lines were higher than 'IR 36' in anther culture among selected 34 $BC_2F_4$ lines. The ability of plant regeneration of 10 lines were higher than 'IR 36' in the seed culture among selected 34 $BC_2F_4$ lines. A promising line, $BC_2F_4$-28, was selected to have better culturability in the anther and seed culture among selected 34 $BC_2F_4$ lines. The heading date and grain shape of the $BC_2F_4$-28 was similar to 'IR 36'. Using the RZ400 DNA marker associated with the culturability will be useful method for improving of indica rice culticvar's culturability in rice breeding program.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.3
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• pp.244-249
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• 1992

To investigate the varietal variations in absolute density of milled rice grain and its relations with other grain characters, the 235 rice varieties which consist of 30 Tongil type rices, 72 Japonica rices and 133 Indica rices were tested on grain size, volume, hardness, chalkiness and 1000 grains weight of brown rice, ADV, amylose content, starch composition on SEM and absolute density of milled rice grain using completely ripened grains. Average absolute density of milled rice grain was 1.496g / cm$^3$ in Tongil type rices, 1.506g / em in Japonica rices, and 1.500g / cm$^3$ in Indica rices. It was correlated positively with days to heading and grain hardness, and negatively with chalkiness, volume, grain weight and grain length of brown rice. Regression analysis indicated that grain volume and weight were the major characters affecting the density. However, since the absolute density of milled rice grain did not show great varietal variations it might not seem important as one of the characters contributing to the grain yield, while it could be a factor affecting the grain quality because there were definite varietal differences even though small. The microscopic feature of starch composition on SEM revealed differences between clear and chalky parts of the grain in shape and compactness of starch composition but did not discriminate between high and low-density grains.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.36 no.3
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• pp.271-279
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• 1991

The changes in fat acidity of brown rice and eating quality of rice during long term grain storage of unhulled rice were evaluated for the government managed rices. The Tongil type rice grains had consistently significantly lower fat acidity during three and half year storage than the Japonica type rice. On sensory evaluation of the fresh milled cooked rice the eating quality of the long term stored rices, 1987, 1988, and 1989 produce Tongil did not differ much each other even though increase in fat acidity by year of storage. The Japonica rices produced in 1989 and 1990 in different locations and stored there also did not differ much in eating quality. The grains stored in storehouses of super grade did not differ significantly from those stored in the first grades, but the grains stored (4 $^{\circ}C$, RH 50%) grains have kept the eating quality almost same as the fresh grains even after two and half years. A higher degree of milling did not improve significantly the sensory taste of cooked rice of the grains long term stored.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.52 no.4
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• pp.375-379
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• 2007

This study was carried out to examine the effects of storage duration on physico-chemical properties of milled rice. Rough rice of three rice ecotypes(Japonica, Tongil and F1 hybrids with Tongil back-ground) was stored for 4, 16, 28 and 40 months without artificial environmental control in seed warehouse. And this materials were investigated for seed germination rate, brown rice hardness, alkali digestion value(ADV), contents of protein, amylose, total sugar, and reducing sugar. Seed germination rate was significantly reduced with storage duration increased regardless of rice ecotypes : 66.7% from 16 months storage, 2.5% from 28, and nil from 40 months storage in Japonica rices. And 54.0%, 67.9% in Tongil, and F1 hybrid after 40 months storage, respectively. Brown rice hardness was not significantly affected by storage duration but showed significant genotypic differences. As the storage duration prolonged, sugar content and alkali digestion value increased, protein content declined while amylose content did not show clear tendency. Total and reducing sugar contents showed sharp increase upto 16 months storage and thereafter steady in crease, and the percentage of reducing sugar content out of total sugar content increased with extended storage duration.