• KOREAN JOURNAL OF CROP SCIENCE
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• v.33 no.4
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• pp.370-374
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• 1988

The study was objected to compare the differential responses in photosynthesis and resipiration by selected cultivars as tolerant or susceptible to oxyfluorfen and bensulfuron-methyl. Clark-typed oxygen elect rude system (Rank Brothers Co., Bottisham. UK.) was used to detect the releasing oxygen from the leaf disks. By increasing oxyfluorfen concentrations. both cultivars were disposed to decrease in photosynthetic O$_2$ generation and increase in respiratory O$_2$ generation. Comparing of both rice cultivars. cv. Mushakdanti (selected at 10$\^$-3/M as the susceptible) failed down in photosynthetic O$_2$ generation as lower as 43% of the control but cv. Aichiasahi to 55%, respectively. However. no significant difference in respiratory O$_2$ generation were detected between both cultivars. As for bensulfuron-methyl. almost same tendency was conferable with general responses on O$_2$ generation between both selected cultivars, namely cv. IR 1846 failed down in photosynthetic O$_2$ generation as lower as 55% of the control but cv. Chinsurah Boro II to 77%. respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.33 no.4
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• pp.375-379
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• 1988

To identify the evidence in tolerance to oxyfluorfen between selected rice cultivars (cv. Chokoto as the tolerant and cv. Weld Pally as the susceptible), the differences in ehtylene evolution, chlorophyll contents and electro-conductivity as affected by various concentrations of oxyfluorfen were assessed. -Under 10$^{-5}$ M oxyfluorfen, the susceptible cultivar showed rapid and higher rate of ethylene evolution, and under 10$^{-4}$ M oxyfluorfen, less difference in ethylene evolution between both cultivars. -Upto 10$^{-6}$ M oxyfluorfen, no difference in chlorophyll contents of both cultivars, however, at 10$^{-5}$ ~10$^{-4}$ M, the susceptible showed as less chlorophyll contents as half of the tolerant. At 10$^{-3}$ M, both cultivars showed complete decomposition of chlorophyll. -At 10$^{-4}$ ~10$^{-3}$ M oxyfluorfen. both cultivars indicate the increased rate in electro-conductivity, and the susceptible cultivar released as much electrolytes as 10% of the tolerant.

• Proceedings of the Korean Journal of Food and Nutrition Conference
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• 2001.12a
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• pp.39-74
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• 2001

The endeavors enhancing the grain quality of high-yielding japonica rice were steadily continued during 1980s∼1990s along with the self-sufficiency of rice production and the increasing demands of high-quality rices. During this time, considerably great, progress and success was obtained in development of high-quality japonica cultivars and qualify evaluation techniques including the elucidation of interrelationship between the physicochemical properties of rice grain and the physical or palatability components of cooked rice. In 1990s, some high-quality japonica rice caltivars and special rices adaptable for food processing such as large kernel, chalky endosperm aromatic and colored rices were developed and its objective preference and utility was also examined by a palatability meter, rapid-visco analyzer and texture analyzer. The water uptake rate and the maximum water absorption ratio showed significantly negative correlations with the K/Mg ratio and alkali digestion value(ADV) of milled rice. The rice materials showing the higher amount of hot water absorption exhibited the larger volume expansion of cooked rice. The harder rices with lower moisture content revealed the higher rate of water uptake at twenty minutes after soaking and the higher ratio of maximum water uptake under the room temperature condition. These water uptake characteristics were not associated with the protein and amylose contents of milled rice and the palatability of cooked rice. The water/rice ratio (in w/w basis) for optimum cooking was averaged to 1.52 in dry milled rices (12% wet basis) with varietal range from 1.45 to 1.61 and the expansion ratio of milled rice after proper boiling was average to 2.63(in v/v basis). The major physicochemical components of rice grain associated with the palatability of cooked rice were examined using japonica rice materials showing narrow varietal variation in grain size and shape, alkali digestibility, gel consistency, amylose and protein contents, but considerable difference in appearance and torture of cooked rice. The glossiness or gross palatability score of cooked rice were closely associated with the peak. hot paste and consistency viscosities of viscogram with year difference. The high-quality rice variety “Ilpumbyeo” showed less portion of amylose on the outer layer of milled rice grain and less and slower change in iodine blue value of extracted paste during twenty minutes of boiling. This highly palatable rice also exhibited very fine net structure in outer layer and fine-spongy and well-swollen shape of gelatinized starch granules in inner layer and core of cooked rice kernel compared with the poor palatable rice through image of scanning electronic mcroscope. Gross sensory score of cooked rice could be estimated by multiple linear regression formula, deduced from relationship between rice quality components mentioned above and eating quality of cooked rice, with high Probability of determination. The ${\alpha}$ -amylose-iodine method was adopted for checking the varietal difference in retrogradation of cooked rice. The rice cultivars revealing the relatively slow retrogradation in aged cooked rice were Ilpumbyeo, Chucheongbyeo, Sasanishiki, Jinbubyeo and Koshihikari. A Tongil-type rice, Taebaegbyeo, and a japonica cultivar, Seomjinbyeo, shelved the relatively fast deterioration of cooked rice. Generally, the better rice cultivars in eating quality of cooked rice showed less retrogiadation and much sponginess in cooled cooked rice. Also, the rice varieties exhibiting less retrogradation in cooled cooked rice revealed higher hot viscosity and lower cool viscosity of rice flour in amylogram. The sponginess of cooled cooked rice was closely associated with magnesium content and volume expansion of cooked rice. The hardness-changed ratio of cooked rice by cooling was negatively correlated with solids amount extracted during boiling and volume expansion of cooked rice. The major physicochemical properties of rice grain closely related to the palatability of cooked rice may be directly or indirectly associated with the retrogradation characteristics of cooked rice. The softer gel consistency and lower amylose content in milled rice revealed the higher ratio of popped rice and larger bulk density of popping. The stronger hardness of rice grain showed relatively higher ratio of popping and the more chalky or less translucent rice exhibited the lower ratio of intact popped brown rice. The potassium and magnesium contents of milled rice were negatively associated with gross score of noodle making mixed with wheat flour in half and the better rice for noodle making revealed relatively less amount of solid extraction during boiling. The more volume expansion of batters for making brown rice bread resulted the better loaf formation and more springiness in rice bread. The higher protein rices produced relatively the more moist white rice bread. The springiness of rice bread was also significantly correlated with high amylose content and hard gel consistency. The completely chalky and large gram rices showed better suitability for fermentation and brewing. Our breeding efforts on rice quality improvement for the future should focus on enhancement of palatability of cooked rice and marketing qualify as well as the diversification in morphological and physicochemical characteristics of rice grain for various value-added rice food processings.

• Journal of Photoscience
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• v.9 no.2
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• pp.329-331
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• 2002

There is a difference in the inhibitory effects to supplemental UVB (wavelengths 280 to 320 nm) among Japanese rice (Oryza sativa L.), the cultivar Norin I is less resistant while the cultivar Sasanishiki is resistant. UVB induces photodamage in DNA. Cyclobutane pyrimidine dimer (CPD) is a major UV-induced DNA lesion. Photorepair, which is mediated by photolyase, is the major pathway in plants for repairing CPD. We have analyzed CPD induction and repair in Sasanishiki and its close relative Norin I using alkaline agarose gel electrophoresis. Norin I is deficient in CPD photoreactivation and excision, thus UV sensitivity correlates with deficient dimer repair [I]. The photorepair deficiency in Norin I results from a functionally altered photolyase with a photoflash analysis [2]. In this paper, we examined the UVB-sensitivity of several other UV-sensitive and -resistant cultivars and found that the CPD photolyase activity was deficient in UV-sensitive ones. It was also evident that there was a variation in the deduced amino acid sequences of CPD photolyases of the UV-sensitive and -resistant cultivars, whereas each deduced amino acid sequence of the UV-sensitive cultivars and of the UV-resistant ones was the same. These results suggest that the difference in the CPD photolyases of UV-sensitive and -resistant rice might be due to the structural alteration of CPD photolyase.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.2
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• pp.78-83
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• 2001

Two rice cultivars of the japonica type, ozone-resistant Ilpumbyeo (IL) and ozone-susceptible Keu-mobyeo#l (KM) were exposed to ozone ($O_3$) at 0.15 ppm for 30 days. The available nutrient regimes were varied by doubling the supply of nitrogen (N), phosphorus (P) and potassium (K) within a basic fertilizer status (N, P, K; 15, 12, 12 kg l0$a^{-1}$). There was little difference on plant height between ozone-treated and nontreated plants. The most significant ozone stress on tiller number was shown on the 30th day of ozone exposure. Slight recovery from ozone stress was noted on the 60th day. On the 30th day, tiller number was greatly decreased by 40.8% in IL and 64.6% in KM, whereas at a high nitrogen supply regime (2N), it was decreased by 21.4% in IL and 42.7% in KM as compared to the control not treated with ozone at basic fertilizer status. The inhibition of tiller production caused by ozone exposure was alleviated on the 60th day. In both cultivars, number of spikelets per plant and weight of 100 grains were affected little by the ozone treatment irrespective of nutrient regime. However, the number of panicles per plant and yield were reduced significantly. In both cultivars, yield of ozone-treated plants with 2N status was 12.4-16.1 % higher than that of the ozone-treated plants with basic nutrient status. A significant yield decrease of 47.8% and 33.4% was observed for IL and KM, respectively, in ozone-treated plants with higher potassium (2K) status.

• Journal of the East Asian Society of Dietary Life
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• v.14 no.2
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• pp.145-155
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• 2004

From the cooking data, Japanese rice showed higher water uptake but lower expansion volume, pH and iodine blue value than those of Korean rice. Japanese rice had higher maximum viscosity, breakdown viscosity and pasting temperature but lower final viscosity and setback viscosity than those of Korean rice by RVA analysis. Japanese rice had higher LC (low compression) hardness, U stickiness and HC (high compression) stickiness, LC balance and HC balance, but had lower HC hardness and thickness in the tensipresser data. Also Japanese rice had higher stickiness and balance, and lower hardness from the texturometer analysis. Japanese rice showed higher a cooked taste score than that of the Satake cooked taste machine. The various mean values of Japanese rice after cooking showed better cooking characteristics than the Korean rice. These results might be caused because Japanese rice had a little lower amylose and protein content, but higher tat acidity content.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.58 no.4
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• pp.367-375
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• 2013

The rice bran, a by-product of rice milling process, is well known for various functional components, such as tocopherol, tocotrienol, ${\gamma}$-oryzanol, carrying antioxidant activities. This study was conducted to investigate the antioxidant components and antioxidant activities in rice bran of different Korean rice cultivars. The 8 isomers of vitamin E, ${\gamma}$-oryzanol, flavonoids, and polyphenolics in rice bran from 16 Korean premium and high quality rice cultivars were quantified. DPPH and ABTS radical scavenging activities and reducing power of the ethanol extracts of rice bran were measured. 'Hopum' showed the highest total vitamin E content, $221.47{\mu}g/g$ among the cultivars, and 'Hanseol' showed the lowest content. The rice bran showed different compositions of ${\alpha}-$, ${\beta}-$, ${\gamma}-$, ${\delta}-$ tocopherol and tocotrienol among rice cultivars. The antioxidant contents were also different by cultivar; the ${\gamma}$-oryzanol contents ranged from 1.99 mg/g (Unkwang) to 4.30 mg/g (Chilbo), the polyphenol contents ranged from 427.22 mg gallic acid eq./100 g (Odaebyeo) to 775.80 mg gallic acid eq./100 g (Hopum). 'Hopum' also had the highest DPPH and ABTS free radical scavenging activities, 9.82% and 187.5 AEAC mg/100 g, respectively. In vitro, the rice bran extracts from 'Hopum' had significantly higher antioxidant activities than that of other cultivars.

• Korean Journal of Environmental Agriculture
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• v.16 no.3
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• pp.245-248
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• 1997

The study was carried out to elucidate the changes of ${\alpha}-amylase$ activity and free proline content for zinc toxicity in two rice cultivars(Ilpumbyeo and Namchunbyeo) during germination and early growth stages. Plant height in all kinetin treatments was promoted but zinc 120ppm treatment was decreased. Soaking treatment of kinetin $10^{-3}M$ increased germination rate of both cultivars, Ilpumbyeo and Namchunbyeo by 95% and 96% as compared with zinc 120ppm. Chlorophyll content of Ilpumbyeo was higher than that of Namchunbyeo. Activity of ${\alpha}-amylase$ in kinetin $10^{-3}M$ of both rice cultivars was most highest in the 3days after treatment of zinc 120ppm. Free proline content in all rice cultivars of zinc 120ppm treatment was sharply increased at the 3days after treatment of zinc 120ppm. As a result, the effects of kinetin treatment were recognized to promote the plant height and germination rate under zinc toxicity(120ppm) during rice seed germination and early growth stages.

• Korean Journal of Food Science and Technology
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• v.35 no.4
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• pp.696-701
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• 2003

Rice seeds of 4 cultivars including Whachung and Nampung, of the non-waxy rice cultivars, and Shinsunchalbyeo and Whachungchabyeo, of the waxy rice cultivars, were germinated at $27^{\circ}C$ for 3 days to compare the changes in some physico-chemical properties of the starch granules and the starch-hydrolysing enzyme activities during germination, respectively. With the starch granules, the amount of long glucose chains from amylose molecules were reduced in the non-waxy rices, while the chain length increased in the waxy rices. In the distribution profile of the glucose chain length from amylose molecules, we could observed that the chain length with DP (degree of polymerization) ranged 33 to 66 increased with the decreasing rate of the chain length with that above 130, regardless of the waxiness of rices. In addition, we observed that in contrast to a increase in chain length with DP ranged 14 to 33, the amount of short chains from A chain fraction decreased. Germination induced slight reduction in the polymerization rate of starch granules, and decrease in both initiation and termination temperatures for the gelatinization. ${\alpha}-Amylase$ activity of rices germinated for 3 days found to he higher than that of malt. Especially, the activity of Shinsunchalbyeo was revealed to be highest, about two fold higher than that of malt. In contrast, ${\beta}-amylase$ of the waxy rice found to be considerably less active than malt, although the waxy showed prevalent activity as compared to the non-waxy rices.

• Proceedings of the Korean Society of Crop Science Conference
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• 2000.11a
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• pp.28-45
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• 2000

It was unusual crop weather for 1998 and 1999 compared with normal in Korea. The consecutive days of the optimum ripening period for rice plant that had daily mean temperature 21-23C for 40 days after heading, increased with long anomalies in 1998-99. The air temperature during ripening period was much higher than the optimum temperature and lower sunshine hour than normal in the local adaptability tests of newly developed rice lines during those years. In response of rice cultivation to warming and cloudy weather during crop season, the yield shall be decreased. Most scientists agree that the rate of heating is accelerating and temperature change could become increasingly disruptive. Weather patterns should also become more erratic. Agrometeorologists could be analyzed yearly variations of temperature, sunshine hour and rainfall pattern focused on transient agroclimate change for last a decade. Rice agronomists could be established taking advantage of real time agricultural meteorology information system for fertilization, irrigation, pest control and harvest. Also they could be analyzed the characteristics of flowering response of the recommended and newly bred rice cultivars for suitable cropping plan such as cultural patterns and sowing or transplanting date. Rice breeders should be deeply considered introducing the characteristics of basic vegetative type of flowering response like Tonsil rices as prospective rice cultivars corresponding to global warming because of the rices needed higher temperature at ripening stage than Japonica rices, photoperiod sensitive and thermo-sensitive ecotypes