• Journal of Crop Science and Biotechnology
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• v.10 no.4
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• pp.257-264
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• 2007

Rice is one of the world's staple crops and is a major source of carbohydrate. Rice is exported from several countries, providing a major source of income. There are many documents reporting that rice is a salt-sensitive crop in its developmental stages. The objective of this investigation is to evaluate the effective salt-tolerance defense mechanisms in aromatic rice varieties. Pathumthani 1(PT1), Jasmine(KDML105), and Homjan(HJ) aromatic rice varieties were chosen as plant materials. Rice seedlings photoautotrophically grown in-vitro were treated with 0, 85, 171, 256, 342, and 427 mM NaCl in the media. Data, including sodium ion$(Na^+)$ and potassium ion$(K^+)$ accumulation, osmolarity, chlorophyll pigment concentration, and the fresh and dry weights of seedlings were collected after salt-treatment for 5 days. $Na^+$ in salt-stressed seedlings gradually accumulated, while $K^+$ decreased, especially in the 342-427 mM NaCl salt treatments. The $Na^+$ accumulation in both salt-stressed root and leaf tissues was positively related to osmolarity, leading to chlorophyll degradation. In the case of the different rice varieties, the results showed that the HJ variety was identified as being salt-tolerant, maintaining root and shoot osmolarities as well as pigment stabilization when exposed to salt stress or $Na^+$ enrichment in the cells. On the other hand, PT1 and KDML105 varieties were classified as salt-sensitive, determined by chlorophyll degradation using Hierarchical cluster analysis. In conclusion, the HJ-salt tolerant variety should be further utilized as a parental line or genetic resource in breeding programs because of the osmoregulation defensive response to salt-stress.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.1
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• pp.38-45
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• 1993

Gel consistency data collected from various experiments in same location during 1988 to 1992 were analysed to clarify the degree of varietal and environmental variation in rice. Most of japonica and Tongil-type rice varieties were belonged to soft gel consistency, and average gel length of japonica rice was longer than that of Tongil-type varieties. Gel length of glutinous rice cultivars was extremely long, near 100mm. Year variation of gel consistency was recognized, but did not affect on varietal difference. Gel consistency of most rice varieties and pedigree lines tested varied slightly between different seeding dates or nitrogen levels, but gel length of two indica rice varieties were decreased with the later seeding dates or the higher nitrogen levels. Rice varieties belonged to extremely hard or extremely soft gel consistency showed less variation of gel length between different years, seeding dates or nitrogen levels compared with intermediate ones.

• Korean Journal of Food Science and Technology
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• v.22 no.2
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• pp.227-228
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• 1990

The cooking properties of waxy rice, Olchal (Japonica type) and Hangang-chalbyeo $(J{\times}\;Indica\;type)$, were studied. The values of cooking rate constant of Hanganchalbyeo were higher than those of Olchal. However, the activation energies were essentially the same. The activation energy for cooking at $80-100^{\circ}C$ was about 1.6 times greater than at $100-120^{\circ}C$. The Z-value and $Q_{10}$ calculated from the terminal point of cooking were also similar between waxy rices.

• Journal of Biosystems Engineering
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• v.14 no.1
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• pp.8-15
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• 1989

Agricultural materials do not react in a purely elastic manner, and their responses when subjected to stress and strain are appeared from a combination of elastic and viscous behavior. Various researchers have studied the mechanical and rheological properties of the many agricultural materials, but those properties are available mostly foreign varieties of agricultural products. Rheological properties of rice seedlings become important to formulate the principles governing their mechanical behavior. The objectives of this study were to experimentally determine the stress relaxation properties of rice seedlings such as three Japonica-type and one Indica ${\times}$ Japonica hybrid in the transplanting age. The results of this study are summarized as follows; 1. The stress relaxation behavior could be described by the generalized Maxwell model. 2. The phenomenon of stress relaxation happened abruptly just after loading and this phenomenon weakened with the loading time lapsed. 3. With increase of the initial stress, the stress relaxation intensity and residual stress increased, while the relaxation time was constant with increased, while the relaxation time was constant with increase of the level of initial stress. 4. With increase of loading rate, the stress relaxation intensity increased, while the relaxation time and residual stress decreased.

• Korean journal of food and cookery science
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• v.7 no.2
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• pp.1-6
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• 1991

The sensory properties and the change of lipid content of cooked rice were investigated to evaluate the effects of cooker (electric and pressure cooker) and variety ($Japonica and Indica\timesJaponica variety$). Overall preference of cooked rices were higher in the pressure cooker than the electric cooker. In the case of electric cooker, Japonica variety was prefered than $I\timesJ$ variety. Free lipid contents were reduced and bound lipid contents were increased after cooking. The bound lipid contents had a correlation with shiness of cooked rice(r=-0.69).

• KOREAN JOURNAL OF CROP SCIENCE
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• v.68 no.4
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• pp.262-275
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• 2023

This study aimed to assess the preferences of African, American, and Asian panels, in comparison to a Korean panel, for various Korean rice varieties, including three japonica, two indica, and one Tongil-type, all developed by the Rural Development Administration in Korea. Regarding rice appearance, most panelists, except for the Koreans, favored long and slender rice varieties like 'Hanyeol', 'Hyangyeol', and 'Amissal'. In contrast, the Koreans preferred wider varieties like 'Sindongjin' and 'Deuraehyang'. Notably, the overseas panelists consistently favored rice varieties with high appearance quality in sensory evaluations of cooked rice. Both overseas and Korean panelists strongly preferred the indica rice variety 'Hanyeol' in terms of appearance quality and sensory evaluations. However, Korean rice varieties like 'Amissal' and 'Sindongjin' scored high in appearance quality with overseas panelists but received low ratings in sensory aspects, including shape, stickiness, and taste, compared to those for 'Hanyeol'. This suggests that considering sensory characteristics is important when exporting Korean rice varieties. Regarding taste characteristics preferred by the panelists derived from the correlation analysis between taste traits, Africans preferred rice with a smooth texture and no stickiness, especially favoring long-grain rice. Americans leaned towards rice with a slightly firm texture, some stickiness, and late aging characteristics. Asians preferred rice with a smooth texture, low stickiness, and long-grain varieties. In contrast, Koreans favored round rice with a glossy appearance, a slightly firm texture, late aging traits, and some stickiness. These research findings can serve as valuable data for the development of rice varieties for overseas markets and are expected to contribute to securing competitiveness in international markets.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.24 no.3
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• pp.7-12
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• 1979

Seven hundred and forty eight rice cultivars were screened for drought tolerance at seedling stage in a special green house. A number of cultivars such as Wonkiljo, Hanyangdo, YR 52-$_{x}\textrm{BF}_7-67, Satominori, Mamoriaka, Akanomochi 114, Thkebenimochi, IR 937-55-3, IR2735-F_3B-6-2, IR 2871-53-2, $_{x}\textrm{BFI76}^9/Dwan, Khoo lliok Mali-4-2-105, Os6, Palawan, IRAT10, TOS 2583 and H-l05 seemed to be tolerant to drought at seedling stage. There was negative correlation between drought resistance score and growth of plant height and water content of culm and leaf after drought treatment, and highly positive correlation between resistance to blast and resistance to drought at seedling stage. There was no relationship between drought resistance and germination speed, plant height before drought treatment.

• Korean Journal of Food Science and Technology
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• v.10 no.2
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• pp.157-161
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• 1978

Physicochemical properties of rice starches from Paldal(japonica type) and Tongil(indica type) were investigated. There were no significant differences in water-binding capacity, blue value and amylose content between the two starches. Paldal starch showed a higher value for-swelling power than Tongil starch. Amylograph data showed that both Paldal and Tongil starches had similar paste viscosities except setback in which Tongil starch showed a higher value. No significant differences were observed for intrinsic viscosity and glucose units per segment between Paldal and Tongil amylopectin fractions. However, the intrinsic viscosity for Tongil amylose was considerably higher than Paldal amylose. The rate of retrogradation of Tongil starch gels at $21^{\circ}C$ was faster than Paldal starch gels.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.32 no.1
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• pp.5-9
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• 1987

In order to investigate the occurrence status of tiller at the upper node of rice, this trial was conducted with different eco-typed and 23 cultivars in 1983 and testified the effect of fertilizer levels with Indica x Japonica cultivars in 1984. In occurring of tiller at the upper nodes, upper 2nd, 3rd node and lower 2nd, 3rd node rose simultaneously. The tillering rates of the upper nodes of Japonica x Indica cultivars were more than Japonica cultivars and early maturing cultivars were more than medium or late maturing cultivars, respectively. Highly negative correlations were found between the tillering rate of upper nodes and days from transplant-ing to heading and bending angle degree of 2nd node. The tilleriiig rate of the upper nodes treated with different levels of fertilizer increased with non-fertilizer than those of standard (N-P-K =15-11-13kg/10a) or heavy (N-P-K =25-15-18kg/10a) levels.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.2
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• pp.103-107
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• 2003

Phosphorus (P) is a macronutrient playing important roles in many plant processes. Significant interest has been devoted to search and utilize genotypic variations in P use efficiency in rice but with little effort to understand its physiological and biochemical bases. In this study, we examined responses to P deprivation of some primary and secondary traits in 3-week-old seedlings of the three genotypes, Sobi-byeo (japonica), Dasan-byeo (japonica $\times$ indica) and Palawan (indica). In general, percent weight due to root was increased up to 26%, but amounts of root protein and proteins secreted from roots were decreased by 11 to 19% and 31 to 51 %, respectively, by 3 to 21 days of P deprivation in the three genotypes. Interestingly, however, responses of Palawan to short-term P deprivation were contrasting to those of Dasan-byeo and Sobi-byeo in seedling weight and contents of shoot protein, chlorophyll and anthocyanin. Seedling weight was not decreased, but shoot protein content was decreased in P-deprived seedlings of Palawan. Contents of chlorophyll in leaves and anthocynin in roots were increased in Dasan-byeo and Sobi-byeo, but decreased in Palawan. The results suggest that responses of protein and pigment synthesis to P deficiency are different in modem and traditional varieties and the difference may at least in part be due to the selection for high yield under highly fertilized conditions.