• Journal of Biosystems Engineering
• /
• v.6 no.1
• /
• pp.73-82
• /
• 1981

The physical properties of grain are very important for the design of handling, sorting, processing, and storage system. On the physical properties of grain, volume, bulk density, true density, specific gravity, and porosity arc the major factors affecting the thermal properties of grain. This study was conducted to determine experimentally the above physical properties of rough rice (3 Japonica-type, 3 Indica-type) and barley (covered, naked) as a function of moisture content ranged from about 10% to 25% (w.b). The results of this study are summarized as follows; 1. The volume of grain kernel increased with moisture content for both rice and barley. The volume of those grain kernel was in the range of $2.2068{\times}10^{-8}{\sim}3.3960{\times}10^{-8}m^3$ at the moisture content of 14%. 2. The bulk density of rice increased linearly with moisture content for Japonica-type rough rice and quadratically for Indica-type rough rice, but the bulk density of barley decreased linearly with moisture content. The bulk density of the grain was in the range of 501.14~689.13kg/$m^3$ at the moisture content of 14%. 3. The true density of whole grain decreased linearly with moisture content, and was in the range of 1019.49~1139.75kg/$m^3$ at the moisture content of 14%. 4. The porosity of rice decreased linearly with moisture content for Japonica-type rough rice and quadratically for Indica-type rough rice, but the porosity of barley increased linearly with moisture content. The porosity of the grain was in the range of 39.51~50.83% at the moisture content of 14%. 5. The regression equations of the physical properties such as volume, bulk density, true density, and porosity of the grain were determined as a function of moisture content.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.48 no.1
• /
• pp.44-49
• /
• 2003

In vitro culture of panicle has been the method to accumulate starch and protein in immature grains by providing nutrients after florets crossed between remote genotypes artificially. Grain filling means embryo development and sucrose translocation from photosynthetic source, and starch manufacture in endosperm. The concentrations of sucrose used to culture immature rice panicle were 5, 10, 15, 20% and glutamine was 20 mM. When immature rice panicles at 5 days after flowering were cultured in distilled water with different concentrations of sucrose, glutamine 20 mM and MS medium with different concentrations of sucrose, glutamine 20 mM for 30 days the later was effective on grain filling. The optimal concentration of sucrose on grain filling in vitro culture of rice panicle was 10% and the weight of grain cultured was 10.14 mg that was corresponded to 57% of intact plant. In the method of treating plant growth regulators, the culture of immature rice panicle adding in MS medium with Kinetin, IAA, $\textrm{GA}_3$ were effective on grain filling than the culturing of immature rice panicle after submerging in solutions of Kinetin, IAA, $\textrm{GA}_3$ for 1day. When immature rice panicle was cultured in MS medium with sucrose 10% and Kinetin 46.47 $\mu$M it was effective on grain filling, respectively. The weight of grain cultured was 13.1mg that was corresponded to 75% of intact and germination rate was 51 %. When immature rice panicles were cultured in medium with different concentrations combined with Kinetin 4.65, 46.47, 464.7 $\mu\textrm{M}$, IAA 5.71, 57.08, 570.80 $\mu\textrm{M}$ for 30 days and in medium with IAA 5.71, 57.08, 570.80 $\mu\textrm{M}$ for 15 days after culturing in medium with Kinetin 4.65, 46.47, 464.70 $\mu\textrm{M}$ for 15 days the effect on grain filling was similar.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.51 no.6
• /
• pp.523-526
• /
• 2006

When $GA_{4}$ was applied to heading stage, it was examined to understand the change of plant hormones and starch during grain filling and ripening. Exogenous gibberellin caused a dramatic decrease in endogenous ABA content. Endogenous $GA_{4}$ content in both superior and inferior part was more promoted in $GA_{4}-treated$ rice grain than in the control. $GA_{1}$ content of an inferior part was not detected in the control and $GA_{4}-treated$ rice otherwise $GA_{4}$ was detected in all grain parts. Ripened grain rate in $GA_{4}-treated$ rice grain was lower than that of the control plant. Amylopectin from $GA_{4}-treated$ grain contained more very short chains with degree of polymerization (DP) between 4 and 8 than amylopectin from the control plant. It suggests strongly that fine structure of rice endosperm may be changed by exogenously applied $GA_{4}$ in rice plants.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.44 no.3
• /
• pp.207-213
• /
• 1999

Thirty-eight glutinous rice varieties were classified into nine groups on the scatter diagram by the upper two principal components (56% contribution to the total information) based on eleven physicochemical characteristics including the viscograms and physical properties of cooked rice. The first principal component was the factor mainly associated with the viscogram characteristics of rice flour emulsion and the second was the factor chiefly related to the physical properties of cooked rice and water absorbability of rice grain. Indica glutinous rices were clearly distinguished from japonica ones by the first principal component score. Javanica glutinous rices were widely distributed on the intermediate zone between indica and japonica or on several japonica rice groups. Significant positive or negative correlations were found among water absorption rates of rice grain, physical properties of cooked rice, and viscogram characteristics of rice flour. Especially in japonica glutinous rices, the breakdown and setback viscosities of rice flour were closely associated with the alkali digestion value of milled rice and the stickiness of cooked rice. The frequency ratio of short glucose chains (A-chain) to intermediate glucose chains (B-chain), the ratio of B- chains to long glucose chains (C-chain) and the relative frequency of A- or B-chain fractions representing the amylopection structure of rice starch was closely associated with the breakdown and setback viscosities of rice flour.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.47 no.1
• /
• pp.36-41
• /
• 2002

Two rice varieties, 'Oochikara' with large grain and 'Hwayeongbyeo' and their progenies (F$_1$, F$_2$, B$_1$ and B$_2$) were tested to understand gene action of morphological traits of rice grain and their relationships. The evaluated traits were 1,000-grain weight, grain length, width, thickness, length-width ratio and chalkiness of brown rice. Correlation between grain weight and chalkiness was highly significant in the all progenies, and grain length were not associated with width and thickness in an F$_2$ population. Scaling test and jonit scaling test revealed that inheritance of grain traits were fitted to additive-dominance model without epistasis. Additive effects for the traits were much greater than the dominance effects.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.51 no.1
• /
• pp.14-25
• /
• 2006

Response of grain yield and milled-rice protein content to nitrogen (N) rates at various growth stages is critical for quantifying real-time and real-amount of applied N requirement for target grain yield and protein content. An experiment including 10 N rate treatments at transplanting, tillering and panicle initiation stages with four rice cultivars in 2003, 6 N treatments with two rice cultivars in 2004 and 2005 was conducted. Increase of N rates at PIS significantly increased both grain yield and milled-rice protein content but increase of N rates at tillering stage significantly increased grain yield but not milledrice protein content. Therefore, high grain yield and low milled-rice protein content would be difficult to obtain only by adjusting N rates at PIS. Internal N use efficiency (INUE) was 60.5 kg grain/kg N accumulation on an average over N treatments, cultivars, and experimental years, showing considerable reduction especially at high shoot N accumulation in the experimental year of low sunshine duration. Milled-rice protein content tended to increase almost linearly with increasing shoot N accumulation, but it revealed big variation even at the same shoot N accumulation at harvest. Milled-rice protein content decreased with increasing INUE. N accumulation in the milled rice increased at an almost constant proportion of 45.5 percent of the shoot N accumulated at harvest, showing slight decresing proportion with the increasing shoot N accumulation.

• Applied Biological Chemistry
• /
• v.20 no.1
• /
• pp.156-170
• /
• 1977

Some of the recent developments and studies in the area of rice protein are reviewed. Protein content and amino acid composition of rice are briefly described. Emphasis is given to characterization of rice protein fractions, effects of protein content on grain properties and lysine content of rice, occurence of protein in rice grain and biosynthesis of protein during grain development.

• Korean Journal of Breeding Science
• /
• v.41 no.4
• /
• pp.429-436
• /
• 2009

We conducted a QTL analysis of grain quality traits using 117 $BC_3F_4$ and $BC_3F_5$ lines developed from a cross between Ilpumbyeo and Moroberekan. Genotypes of 117 $BC_3F_5$ lines were determined using 134 simple sequence repeat (SSR) markers. A linkage map constructed using 134 SSR markers was employed to characterize quantitative trait loci (QTL). The 117 $BC_3F_4$ and $BC_3F_5$ lines were evaluated for eleven grain quality traits in 2005 and 2006. A total of 18 QTLs were identified for eleven traits, and the phenotypic variance explained by each QTL ranged from 9.9% to 35.2%. Moroberekan alleles contributed positive effects in the Ilpumbyeo background at two QTL loci for 1,000 grain weight. Four QTLs, two for chalky rice and one each for 1,000 grain weight and head rice were consistently detected in two consecutive years indicating that these QTLs are stable. Clusters of QTLs were observed in three chromosome regions. One cluster harboring five QTLs including head rice and brown rice ratio near SSR markers RM190 and RM314 was detected on chromosome 6. Another cluster harboring grain weight and white belly was detected on chromosome 2. Increase in white belly at this locus might be due to the increase in grain weight due to the presence of the Moroberekan allele. The Moroberekan alleles at two QTL loci, gw3 and gw4 associated with increased grain weight might be useful in breeding programs to develop high-yielding cultivars.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.46 no.6
• /
• pp.429-433
• /
• 2001

This study was carried out to investigate the occurrence and characteristics of off-type rice plant according to agronomic conditions. The occurrence density of the off-type rice plant in farmer's paddy field was greater as the years of self-produced seed use increased, and in the direct sowing paddy field it was twice as much as in the transplanting paddy field. When the long-grain red rice and the short-grain red rice in the cultivated field of cultivar were artificially sown, in the direct sowing on a flooded paddy surface culture rather than in the machine transplanting culture the off-type rice plant occurred much more, the culm length was longer, and the number of productive culm per plant increased. These characteristics were more conspicuous in the long-grain red rice than in the short-grain red rice. In the transplanting farmer's paddy fields, the off-type rice plant that occurred outside of the hills of the cultivar rice ranged 0 to 6%. Whereas in was 70.6 to 91.9% when the long-grain red rice and short-grain red rice were artificially sown. Therefore, it was assumed that most of the off-type rice plants occurred in the farmer's paddy fields was caused by seed contamination.

• Journal of Biosystems Engineering
• /
• v.15 no.1
• /
• pp.33-43
• /
• 1990

Spectral reflectance of paddy, brown rice, milled rice, greenish grain, yellow grain and denatured grain were measured over the range of 340 to 820 nm with "Double Beam Spectrophotometer(Model UV-180)". Variation in the reflectance depending on milling degree of milled rice appeared greatest over the range of 420 to 500 nm, and that between white rice and other rice samples appeared greatest near 500 nm. On the basis of the above results, a whiteness meter to measure milling degree of rice was manufactured using tungsten lamp, photodiodes and amplifier, and its performance was compared with the existing whiteness meters (KETT and Z-II optical sensor). There were very high correlations among those whiteness meters.