• Title/Summary/Keyword: high-temperature tolerance

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Molecular Characterization of a Novel 1,3-α-3,6-Anhydro-L-Galactosidase, Ahg943, with Cold- and High-Salt-Tolerance from Gayadomonas joobiniege G7

  • Seo, Ju Won;Tsevelkhorloo, Maral;Lee, Chang-Ro;Kim, Sang Hoon;Kang, Dae-Kyung;Asghar, Sajida;Hong, Soon-Kwang
    • Journal of Microbiology and Biotechnology
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    • v.30 no.11
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    • pp.1659-1669
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    • 2020
  • 1,3-α-3,6-anhydro-L-galactosidase (α-neoagarooligosaccharide hydrolase) catalyzes the last step of agar degradation by hydrolyzing neoagarobiose into monomers, D-galactose, and 3,6-anhydro-L-galactose, which is important for the bioindustrial application of algal biomass. Ahg943, from the agarolytic marine bacterium Gayadomonas joobiniege G7, is composed of 423 amino acids (47.96 kDa), including a 22-amino acid signal peptide. It was found to have 67% identity with the α-neoagarooligosaccharide hydrolase ZgAhgA, from Zobellia galactanivorans, but low identity (< 40%) with the other α-neoagarooligosaccharide hydrolases reported. The recombinant Ahg943 (rAhg943, 47.89 kDa), purified from Escherichia coli, was estimated to be a monomer upon gel filtration chromatography, making it quite distinct from other α-neoagarooligosaccharide hydrolases. The rAhg943 hydrolyzed neoagarobiose, neoagarotetraose, and neoagarohexaose into D-galactose, neoagarotriose, and neoagaropentaose, respectively, with a common product, 3,6-anhydro-L-galactose, indicating that it is an exo-acting α-neoagarooligosaccharide hydrolase that releases 3,6-anhydro-L-galactose by hydrolyzing α-1,3 glycosidic bonds from the nonreducing ends of neoagarooligosaccharides. The optimum pH and temperature of Ahg943 activity were 6.0 and 20℃, respectively. In particular, rAhg943 could maintain enzyme activity at 10℃ (71% of the maximum). Complete inhibition of rAhg943 activity by 0.5 mM EDTA was restored and even, remarkably, enhanced by Ca2+ ions. rAhg943 activity was at maximum at 0.5 M NaCl and maintained above 73% of the maximum at 3M NaCl. Km and Vmax of rAhg943 toward neoagarobiose were 9.7 mg/ml and 250 μM/min (3 U/mg), respectively. Therefore, Ahg943 is a unique α-neoagarooligosaccharide hydrolase that has cold- and high-salt-adapted features, and possibly exists as a monomer.

A New High-yielding Rice Variety developed from an Interspecific cross, 'Hwaweon 6' (벼 중생 다수성 중간모본 '화원6호')

  • Kang, Ju-Won;Kim, Dong-Min;Yun, Yeo-Tae;Lee, Hyun-Sook;Park, In-Kyu;Ahn, Sang-Nag
    • Korean Journal of Breeding Science
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    • v.49 no.3
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    • pp.280-284
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    • 2017
  • 'Hwaweon 6' was developed from a cross between 'Hwaseongbyeo' and a wild species, Oryza minuta L. (Acc. No. 101154) based on marker-assisted selection and backcrossing. The recurrent parent 'Hwaseongbyeo' is a high grain quality cultivar with medium maturity. Hwaweon 6 is nearly isogenic to Hwaseongbyeo except a small O. minuta introgressed segment on chromosome 7 harboring genes related with spikelets per panicle. The preliminary and replicated yield trial was conducted at Chungnam National University and Chungcheongnamdo Agricultural Research & Extension (CARES), Yesan in 2009 and 2010. The local adaptability test was carried out by the National Seed Management Office (NSMO) in 2011 and 2012. This cultivar was registered to NSMO with a cultivar designated as Hwaweon 6. This cultivar averaged 80cm in culm length and has a medium growth duration. Milled rice of Hwaweon 6 is translucent and the grain quality traits are comparable to those of the recurrent parent. The average yield potential of Hwaweon 6 in grain was about 6.57 MT/ha at the ordinary fertilizer level for two years about 3.0% higher than that of Hwaseongbyeo due to an introgression of the quantitative trait locus (QTL) for spikelets per panicle (qSPP7) from O. minuta. This variety is comparable to Hwaseongbyeo in low temperature germinability and cold tolerance. The qSPP7 QTL would be useful in enhancing yield potential in rice breeding program.

Enhancement of Plant Growth and Drying Stress Tolerance by Bacillus velezensis YP2 Colonizing Kale Root Endosphere (Bacillus velezensis YP2 균주의 근권 정착에 의한 케일의 생육 촉진 및 건조 스트레스 완화 효과)

  • Kim, Da-Yeon;Han, Ji-Hee;Kim, Jung-Jun;Lee, Sang-Yeob
    • Korean Journal of Organic Agriculture
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    • v.26 no.2
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    • pp.217-232
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    • 2018
  • Drought is a major obstacle to high agricultural productivity, worldwide. In drought, it is usually presented by the simultaneous action of high temperature and drying. Also there are negative effects of plant growth under drying conditions. In this study, the effect of Bacillus velezensis YP2 on plant growth-promotion and soil drying stress tolerance of kale plants, Brassica oleracea var. alboglabra Bailey, were investigated under two different conditions; greenhouse and field environments. Root colonization ability of B. velezensis YP2 was also analysed by using plating culture method. As a result of the greenhouse test, the YP2 strain significantly promoted the growth of kale seedlings in increasement of 26.7% of plant height and 142.2% of shoot fresh weight compared to control. B. velezensis YP2 have the mitigation effect of drying injury of kale by decreasing of 39.4% compared to control. In the field test, B. velezensis YP2 strain was also found to be effective for plant growth-promotion and mitigation of drying stress injury on kale plants. Especially, relative water contents (RWC; %) were higher in B. velezensis YP2 treated kales than in control at 7, 10, 14 day after non-watering. The root colonization ability of YP2 strain was continued at least for 21 days after soil drenching treatment of B. velezensis YP2. Our result suggested that enhancement of plant growth and drying injury reduction of kale plants were involved in kale root colonization by B. velezensis YP2, which might be contributed to increasing water availability of plants. Consequentially, the use of B. velezensis YP2 might be a beneficial influence for improving productivity of kale plants under drying stress conditions.

Microwave Dielectric Properties of (${Pb_{0.2}}{Ca_{0.8}}$)[$({Ca_{1/3}}{Nb_{2/3}})_{1-x}{Ti_x}$]$O_3$ Ceramics (Microwave Dielectric Properties of (${Pb_{0.2}}{Ca_{0.8}}$)[$({Ca_{1/3}}{Nb_{2/3}})_{1-x}{Ti_x}$$O_3$ 세라믹스의 마이크로파 유전특성)

  • Kim, Eung-Soo;Kim, Yong-Hyun;Kim, Jun-Chul;Bang, Kyu-Seok
    • Korean Journal of Materials Research
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    • v.11 no.8
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    • pp.708-712
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    • 2001
  • Microwave dielectric properties of $(Pb_{0.2}Ca_{0.8})[(Ca_{1/3}Nb{2/3})_{1-x}Ti_x]O_3$ ceramics were investigated as a function of $Ti^{4+}$ content (0.05$\leq$x$\leq$0.35). A single perovskite phase was obtained from x=0.05 to x=0.15, and $TiO_2$ and $CaNb_2O^6$ were detected as a secondary phase beyond x=0.2. The structure was changed from orthorhombic at x=0.05 to cubic at x=0.35. Dielectric constant(K) was increased with increase of $Ti^{4+}$ content due to increase of rattling effect, and was inversely proportional to the cube of the average radius of B-site cation, however, Qf value was decreased, which was due to the decrease of grain size and the secondary phase. With the increase of $Ti^{4+}$ content, the temperature coefficient of resonant frequency(TCF) was controlled from -27.36 ppm/$^{\circ}C$ value to +18.4 ppm/$^{\circ}C$ value, which was caused by the influence of tolerance factor(t) and the bond valence of B-site. Typically, K of 51.67, Qf of 7268(GHz), TCF of 0 ppm/$^{\circ}C$ were obtained in the $(Pb_{0.2}Ca_{0.8})[(Ca_{1/3}Nb_{2/3})_{0.8}Ti_0.2]O_3$ sintered at 13$50^{\circ}C$ for 3h.

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A Study on the Prediction of Suitability Change of Forage Crop Italian Ryegrass (Lolium multiflorum L.) using Spatial Distribution Model (공간분포모델을 활용한 사료작물 이탈리안 라이그라스(Lolium multiflorum L.)의 재배적지 변동예측연구)

  • Kim, Hyunae;Hyun, Shinwoo;Kim, Kwang Soo
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.16 no.2
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    • pp.103-113
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    • 2014
  • Under climate change, it is likely that the suitable area for forage crop cultivation would change in Korea. The potential cultivation areas for italian ryegrass (Lolium multiflorum L.), which has been considered one of an important forage crop in Korea, were identified using the EcoCrop model. To minimize the uncertainty associated with future projection under climate change, an ensemble approach was attempted using five climate change scenarios as inputs to the EcoCrop model. Our results indicated that most districts had relatively high suitability, e.g., >80, for italian ryegrass in South Korea. Still, suitability of the crop was considerably low in mountainous areas because it was assumed that a given variety of italian ryegrass had limited cold tolerance. It was predicted that suitability of italian ryegrass would increase until 2050s but decrease in 2080s in a relatively large number of regions due to high temperature. In North Korea, suitability of italian ryegrass was considerably low, e.g., 28 on average. Under climate change, however, it was projected that suitability of italian ryegrass would increase until 2080s. For example, suitability of italian ryegrass was more than 80 in 10 districts out of 14 by 2080s. Because cold tolerance of italian ryegrass varieties has been improved, it would be preferable to optimize parameters of the EcoCrop model for those varieties. In addition, it would be possible to grow italian ryegrass as the second crop following rice in Korea in the future. Thus, it merits further study to identify suitable areas for italian ryegrass cultivation after rice using new varieties of italian ryegrass.

Human Thermal Sensation and Comfort of Beach Areas in Summer - Woljeong-ri Beach, Gujwa-eup, Jeju-si, Jeju Special Self-Governing Province - (여름철 해변지역의 인간 열환경지수 및 열쾌적성 - 제주특별자치도 제주시 구좌읍 월정리 해변 -)

  • Park, Sookuk;Sin, Jihwan;Jo, Sangman;Hyun, Cheolji;Kang, Hoon
    • Journal of the Korean Institute of Landscape Architecture
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    • v.44 no.4
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    • pp.100-108
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    • 2016
  • The climatic index for tourism(CIT) has recently been advanced, which includes complete human energy balance models such as physiological equivalent temperature(PET) and universal thermal climate index(UTCI). This study investigated human thermal sensation and comfort at Woljung-ri Beach, Jeju, Republic of Korea, in spring and summer 2015 for landscape planning and design in beach areas. Microclimatic data measurements and human thermal sensation/comfort surveys from ISO 10551 were conducted together. There were 869 adults that participated. As a result, perceptual and thermal preference that consider only physiological aspects had high coefficients of determination($r^2$) with PET in linear regression analyses: 92.8% and 87.6%, respectively. However, affective evaluation, personal acceptability and personal tolerance, which consider both physiological and psychological aspects, had low $r^2s$: 60.0%, 21.1% and 46.4%, respectively. However, the correlations between them and PET were all significant at the 0.01 level. The neutral PET range in perceptual for human thermal sensation was $25{\sim}27^{\circ}C$, but a PET range less or equal to 20% dissatisfaction, which was recommended by ASHRAE Standard 55, could not be achieved in perceptual. Only PET ranges in affective evaluation and personal tolerance affected by both aspects were qualified for the recommendation as $21{\sim}32^{\circ}C$ and $17{\sim}37^{\circ}C$, respectively. Therefore, the PET range of $21{\sim}32^{\circ}C$ is recommended to be used for the human thermal comfort zone of beach areas in landscape planning and design as well as tourism and recreational planning. PET heat stress level ranges on the beach were $2{\sim}5^{\circ}C$ higher than those in inland urban areas of the Republic of Korea. Also, they were similar to high results of tropical areas such as Taiwan and Nigeria, and higher than those of western and middle Europe and Tel Aviv, Israel.

A New White Wheat Variety, "Jeokjoong" with High Yield, Good Noodle Quality and Moderate to Scab (백립계 다수성 붉은곰팡이병 중도저항성 제면용 밀 신품종 "적중밀")

  • Park, Chlul Soo;Heo, Hwa-Young;Kang, Moon-Suk;Lee, Chun-Kee;Park, Kwang-Geun;Park, Jong-Chul;Kim, Hong-Sik;Kim, Hag-Sin;Hwang, Jong-Jin;Cheong, Young-Keun;Kim, Jung-Gon
    • Korean Journal of Breeding Science
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    • v.40 no.3
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    • pp.308-313
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    • 2008
  • "Jeokjoong", a white winter wheat (Triticum aestivum L.) variety was developed from the cross "Keumkang"/"Tapdong". "Jeokjoong" is an awned, semi-dwarf and soft white winter wheat, similar to "Keumkang" (check variety). The heading and maturing date of "Jeokjoong" were similar to "Keumkang". Culm and spike length of "Jeokjoong" were 78 cm and 7.5 cm, similar to "Keumkang". "Jeokjoong" had lower test weight (800 g) and lower 1,000-grain weight (40.1 g) than "Keumkang" (811 g and 44.0 g, respectively). It had resistance to winter hardiness, wet-soil tolerance and lodging tolerance. "Jeokjoong" showed moderate to scab in test of specific character although "Keumkang" is susceptible to scab. "Jeokjoong" had lower flour yield (69.2%) and ash content (0.36%) than "Keumkang" (72.0% and 0.41%, respectively) and similar flour color to "Keumkang". It showed lower protein content (8.9%) and SDS-sedimentation volume (36.8 ml) and shorter mixograph mixing time (3.5 min) than "Keumkang" (11.0%, 59.7 ml and 4.5 min, respectively). Amylose content and pasting properties of "Jeokjoong" were similar to "Keumkang". "Jeokjoong" had softer and more elastic texture of cooked noodles than "Keumkang". Average yield of "Jeokjoong" in the regional adaptation yield trial was 6.19 MT ha-1 in upland and 5.33 MT/ha in paddy field, which was 19% and 16% higher than those of "Keumkang" (5.21 MT/ha and 4.58 MT/ha, respectively). "Jeokjoong" would be suitable for the area above the daily minimum temperature of $-10^{\circ}C$ in January in Korean peninsula.

A New White Wheat Variety, "Baegjoong" with High Yield, Good Noodle Quality and Moderate to Pre-harvest Sprouting (백립계 다수성 수발아 중도저항성 제면용 밀 신품종 "백중밀")

  • Park, Chul Soo;Heo, Hwa-Young;Kang, Moon-Suk;Lee, Chun-Kee;Park, Kwang-Geun;Park, Jong-Chul;Kim, Hong-Sik;Kim, Hag-Sin;Hwang, Jong-Jin;Cheong, Young-Keun;Kim, Jung-Gon
    • Korean Journal of Breeding Science
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    • v.40 no.2
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    • pp.153-158
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    • 2008
  • "Baegjoong", a white winter wheat (Triticum aestivum L.) cultivar was developed by the National Institute of Crop Science, RDA. It was derived from the cross "Keumkang"/"Olgeuru" during 1996. "Baegjoong" was evaluated as "Iksan307" in Advanced Yield Trial Test in 2004. It was tested in the regional yield trial test between 2005 and 2007. "Baegjoong" is an awned, semi-dwarf and soft white winter wheat, similar to "Keumkang" (check cultivar). The heading and maturing date of "Baegjoong" were similar to "Keumkang". Culm and spike length of "Baegjoong" were 77 cm and 7.5 cm, similar to "Keumkang". "Baegjoong" had lower test weight (802 g) and lower 1,000-grain weight (39.8 g) than "Keumkang" (811 g and 44.0 g, respectively). It had resistance to winter hardiness, wet-soil tolerance and lodging tolerance. "Baegjoong" showed moderate to pre-harvest sprouting (23.9%) although "Keumkang" is susceptible to pre-harvest sprouting (38.9%). "Baegjoong" had similar flour yield (72.4%) and ash content (0.41%) to "Keumkang" (72.0% and 0.41%, respectively) and similar flour color to "Keumkang". It showed lower protein content (8.8%) and SDS-sedimentation volume (35.3 ml) and shorter mixograph mixing time (3.8 min) than "Keumkang" (11.0%, 59.7 ml and 4.5 min, respectively). Amylose content and pasting properties of "Baegjoong" were similar to "Keumkang". "Baegjoong" had softer and more elastic texture of cooked noodles than "Keumkang". Average yield of "Baegjoong" in the regional adaptation yield trial was $5.88\;MT\;ha^{-1}$ in upland and 5.35 MT ha-1 in paddy field, which was 13% and 17% higher than those of "Keumkang" ($5.21\;MT\;ha^{-1}$ and $4.58\;MT\;ha^{-1}$, respectively). "Baegjoong" would be suitable for the area above the daily minimum temperature of $-10^{\circ}C$ in January in Korean peninsula.

Comparison of Non-structural Carbohydrate Concentration Between Zoysiagrass and Creeping Bentgrass During Summer Growing Season (하계 생육기 동안 Zoysiagrass와 Creeping Bentgrass의 비구조적 탄수화물 함량의 비교)

  • Kim, Dae-Hyun;Jung, Woo-Jin;Lee, Bok-Rye;Kim, Kil-Yong;Kim, Tae-Hwan
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.22 no.2
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    • pp.145-152
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    • 2002
  • To compare the Carbon metabolic response to high temperature stress in Zoysiagrass [Zoysia matrella (L.) Merr.] and Creeping bentgrass (Agrostis palustris Huds) with respect to heat tolerance, C metabolites were determined from April to September. Sampling was carried out on an established golf course (Muan Country Club, Chonnam, Korea). Shoot mass(g Dry weight per hole cup) of creeping bentgrass started to decrease from June and recovered from August whereas that of zoysiagrass was less varied. Chlorophyll content in creeping bentgrass was significantly higher than zoysiagrass until July, and then decreased by 43% from July to August. Zoysiagrass contained higher soluble sugar than creeping bentgrass throughout experimental period. Soluble sugar in zoysiagrass increased about 58% from April to May, and less varied until August. Soluble sugar in creeping bentgrass slightly increased until July and sharply decreased at August. Starch concentration in zoysiagrass continuously decreased to September after a significant increase from April to May. A remarkable fluctuation in both starch and fluctuation concentration was observed between June and August showing high accumulation for June to July and high degradation for July to August. These results suggest that through creeping bentgrass suffers much severely from high temperature stress than zoysiagrass especially June to August. An active accumulation and degradation in nonstructural carbohydrate in creeping bentgrass during this period might be associated with heat stress.

Trend and Further Research of Rice Quality Evaluation (쌀의 품질평가 현황과 금후 연구방향)

  • Son, Jong-Rok;Kim, Jae-Hyun;Lee, Jung-Il;Youn, Young-Hwan;Kim, Jae-Kyu;Hwang, Hung-Goo;Moon, Hun-Pal
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.47
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    • pp.33-54
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    • 2002
  • Rice quality is much dependent on the pre-and post harvest management. There are many parameters which influence rice or cooked rice qualitys such as cultivars, climate, soil, harvest time, drying, milling, storage, safety, nutritive value, taste, marketing, eating, cooking conditions, and each nations' food culture. Thus, vice evaluation might not be carried out by only some parameters. Physicochemical evaluation of rice deals with amy-lose content, gelatinizing property, and its relation with taste. The amylose content of good vice in Korea is defined at 17 to 20%. Other parameters considered are as follows; ratio of protein body-1 per total protein amount in relation to taste, and oleic/linoleic acid ratio in relation to storage safety. The rice higher Mg/K ratio is considered as high quality. The optimum value is over 1.5 to 1.6. It was reported that the contents of oligosaccharide, glutamic acid or its derivatives and its proportionalities have high corelation with the taste of rice. Major aromatic compounds in rice have been known as hexanal, acetone, pentanal, butanal, octanal, and heptanal. Recently, it was found that muco-polysaccharides are solubilized during cooking. Cooked rice surface is coated by the muco-polysaccharide. The muco-polysaccharide aye contributing to the consistency and collecting free amino acids and vitamins. Thus, these parameters might be regarded as important items for quality and taste evaluation of rice. Ingredients of rice related with the taste are not confined to the total rice grain. In the internal kernel, starch is main component but nitrogen and mineral compounds are localized at the external kernel. The ingredients related with taste are contained in 91 to 86% part of the outside kernel. For safety that is considered an important evaluation item of rice quality, each residual tolerance limit for agricultural chemicals must be adopted in our country. During drying, rice quality can decline by the reasons of high drying temperature, overdrying, and rapid drying. These result in cracked grain or decolored kernel. Intrinsic enzymes react partially during the rice storage. Because of these enzymes, starch, lipid, or protein can be slowly degraded, resulting in the decline of appearance quality, occurrence of aging aroma, and increased hardness of cooked rice. Milling conditions concerned with quality are paddy quality, milling method, and milling machines. To produce high quality rice, head rice must contain over three fourths of the normal rice kernels, and broken, damaged, colored, and immature kernels must be eliminated. In addition to milling equipment, color sorter and length grader must be installed for the production of such rice. Head rice was examined using the 45 brand rices circulating in Korea, Japan, America, Australia, and China. It was found that the head rice rate of brand rice in our country was approximately 57.4% and 80-86% in foreign countries. In order to develop a rice quality evaluation system, evaluation of technics must be further developed : more detailed measure of qualities, search for taste-related components, creation and grade classification of quality evaluation factors at each management stage of treatment after harvest, evaluation of rice as food material as well as for rice cooking, and method development for simple evaluation and establishment of equation for palatability. On policy concerns, the following must be conducted : development of price discrimination in conformity to rice cultivar and grade under the basis of quality evaluation method, fixation of head rice branding, and introduction of low temperature circulation.