• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.5
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• pp.431-435
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• 1992

This experiment was carried out to evaluate Korean red rices as useful genetic resource. Semi-wild red rices were collected from farmer's field of the Korean peninsula from 1988 to 1991. The collected red rices were classified into two groups according to length /width ratio of paddy rice and ecological characters. One was long grain red rice and the other was short grain red rice. Those were evaluated in yield components, culm length and panicle length. Mean number of panicles per hill of collected long grain red rices was 21.5 and that of short grain was 11.8. Number of spikelets per panicile of the long and short grain red rices were 86.1 and 108.7, respectively. 1000 grains weight of long grain was 20.1g and that of short grain was 20.2g. Spikelet fertility of long and short grain were 80.4% and 79.4%, respectively. Culm length of long grain was 103.6cm and that of short grain was 94.8cm. Panicle length of long and short grain were 22.1cm and 21.3cm, respectively. Number of panicles per hill, number of spikelets per panicle and culm length were significantly different between the two groups, however no differences, in panicle, length and seed fertility were found between the two groups.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.5
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• pp.425-430
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• 1992

This experiment was carried out to collect the Korean red rices and to evaluate them as useful germplasm, 1,113 lines of weedy red rices were collected from farmer's field of the Korean peninsula from 1988 to 1991. The collected red rices were classified into two groups : One was long grain type with length /width ratio of 3.01$\pm$0.11 in paddy rice and the other was short grain type with length /width ratio of 2.28$\pm$0.12. Among the collected red rices 289 lines were long grain type and 824 lines were short. The red rices of long grain type were distributed in Nagdong and Seomjin river vallies of the southern part of the Korean peninsula, and the short ones were distributed all around of the peninsula. Among the collected long grain type red rices, 90.8% was red and 9.2% was white, and among the short grain type 88.8% was red, 10.6% was brown and 0.6% was white in pericarp color. 9.3% of the long grain type and 30.7% of the short grain type of the Korean red rices reacted to phenol solution. In the short grain type, 4.3% was waxy grained, but no waxy line was found in the long grain type. All the long grained Korean red rice showed easy shattering and no awn, however in the short grained red rices, 85.2% showed easy shattering and 49.6% was awned.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.1
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• pp.29-35
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• 2002

This study was carried out to investigate the characteristics of shattering habit and germination of offtype rice plants collected in Korea which were classified into seven groups based on grain characteristics. In the long-grain red rice group, the short-grain red rice group, the long-grain normal rice group, and the long-grain waxy rice group, the tensile strength of grain and primary rachis branch was relatively low and the fiber cell of the primary rachis branch was short. Characteristics of shattering-related traits and germination in relation to grain and esterase isozyme zymogram type of off-type rice plants. In most lines of the extremely late and sterile rice group, the tensile strength of grain was low, while that of primary rachis branch was high, and the fiber cell was long. However, in the type 1 esterase isozyme zymogram(EIZ) lines among the long-grain normal rice group and the type 6 and 5+6 EIZ plants among the extremely late and sterile rice group, the tensile strength of grain was relatively higher. The long-grain waxy rice group and the type 3 EIZ lines among the long-grain red rice group, showed higher germinability than did cultivars which are known to germinate well even in low-temperature. The other off-type rice group, except for the short-grain waxy rice group and type 1 and 7 EIZ lines among the long-grain normal rice group, had higher germination speed than that of the cultivars.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.2
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• pp.134-138
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• 1993

Four lines of the long grain and four lines of the short grain Korean red rices were grown at different nitrogen levels of 0, 7.5, 15.0, 22.5kg /10a. Nitrogen levels and red rice lines were arranged by the respective strip plot design for the long and short grain types. Yield components and yield were tested. Number of panicles per hill and number of spikelet per panicle increased along with the nitrogen levels. One thousand grain weight of the long grain red rices decreased by increasing the nitrogen levels, while that of the short grain red rices was not changed along with nitrogen levels. Grain yield of the long grain red rices increased to the nitrogen level of 22.5kg /l0a, however, that of the short grain red rices increased to the level of 7.5kg /l0a and was not changed over there.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.2
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• pp.128-133
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• 1993

This experiment was carried out to evaluate the germination characteristics of Korean red rice seeds. Ten lines of the long grain and ten lines of the short grain Korean red rices were tested for dormancy, shoot emergence rate at different water and soil depth. Both the long and short grain type seeds of Korean red rice germinated over than 99% immediately after harvest, so that no dormancy was observed in the Korean red rices. Shoot emergence rate of the long grain red rices at 7cm of water depth and that of the short grain red rices at 11cm were 83.3% and 83.5% respectively, while those of the indica check Samgangbyeo and japonica check Seomjinbyeo were 0%. Shoot emergence rates of the long and short grain red rices at 7cm of soil depth were 71.1% and 73.9% respectively, while those of the check varieties Samgangbyeo and Seomjinbyeo were 40.0% and 28.0% respectively. Thus, the Korean red rices were expected to be useful germplasm source for direct seeding.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.3
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• pp.170-175
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• 2001

This study was carried out to investigate the distribution and characteristics of off-type rice plant in farmer's paddy field. The ratio of the field contaminated by off-type rice was highest in the southwestern area, followed by the southeastern area, the central area in Korea. The occurrence density of off-type rice was higher in the southern area than the central area. The short-grain red rice was the most dominant off-type rice group, followed by extremely late and sterile rice group and long-grain red rice group in Korea. The long-grain red rice group was dominant in Jeonnam and Kyongnam, and the extremely late and sterile rice group was dominant in Jeonbuk, and the short-grain red rice group in the other provinces. The culm length of most off-type rice groups growing in the farmer's paddy fields was longer than the farmer's cultivars, and the long-grain red rice group and the short-grain red rice group were especially longer. The number of spikelets per panicle of the off-type rice groups were generally greater than the farmer's cultlvars, and in particular, the extremely late and sterile rice group and the long-grain normal rice group had more spikelet per panicle. Most of the off-type rice groups were extremely sterile.

• Journal of Biosystems Engineering
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• v.12 no.2
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• pp.38-43
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• 1987

An experimental study was conducted to develop a thin-layer rewetting equation of short grain rough rice of Akihikari variety. Four thin-layer rewetting equations were experimentally determined from $25^{\circ}C$ to $45^{\circ}C$ and 70%RH to 85%RH conditions. Diffusion, Henderson, Page, and Thompson equations widely used as thin-layer drying equations were selected. Experimental data were fitted to these equations using linear regression analysis except diffusion equation. The diffusivity in the diffusion equation was determined by optimization method. Four equations were highly significant. In order to compare the goodness of fit of each equation, the error mean square of each equawas calculated. The diffusion model was not a very good model because the error mean square was very large. The other three models showed the same level or error mean square and could predict satisfactorily the rewetting rate or short grain rough rice.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.10
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• pp.1726-1734
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• 2004

Response surface methodology on sensory evaluation was used to optimize cooking condition of cooked short grain rice (CSR) and cooked short grain rice containing grainy sea-tangle patch (CSTR). Texture profile analysis and nutritional evaluation were also performed. For maximizing overall acceptability, it can be predicted sea-tangle patch 14%, added water 1.67 times of rice and sea-tangle amount and steeping time 47 min as optimum cooking conditions from sensory evaluation conducted by the forties panelist. Hardness of pressure cooked short grain rice containing grainy sea-tangle patch (CSTR) were lower than cooked short grain rice (CSR), but it showed similar as CSR in adhesiveness, chewiness and higher in springiness and cohesiveness. In addition CSTR was delayed retrogradation compared with CSR. The nutritional Quality of CSTR showed higher level in total dietary fiber, protein, ash than CSR, but lower in protein digestibility, C-PER, gelatinization degree compared with CSR.

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

• 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.