최고품질 벼 칠보의 적정 수확시기를 구명하고자 농업환경이 서로 다른 밀양, 사천, 함양, 상주, 울진 등 5개 지역에서벼를 재배한 후 각 지역별 최적 수확시기를 검토한 결과는 다음과 같다. 1. 기후대에 따라 출수기에서 출수 후 60일까지의 평균기온은 사천이 가장 높았고, 상주가 가장 낮았다. 상주는 평균기온의 저하정도가 다른 지역에 비해 컸으며 울진은 등숙기 평균기온은 낮았지만 온도저하 정도는 가장 적었다. 2. 지역별로 최고수량을 나타내는 수확시기는 지역간의 차이가 있었는데, 백미수량은 밀양과 함양이 60일, 울진과 상주는 55일, 사천은 45일이었고, 완전미 수량은 상주, 사천, 함양은 60일, 밀양, 울진이 50일로 대체로 출수후 50 ~ 60일 사이었다. 이를 적산온도로 환산할 경우 밀양, 함양은 1,200oC, 상주는 1,050oC, 사천, 울진은 1,100oC 부근이었다. 3. 각 지역별로 최고수량을 나타낸 수확시기의 수량을 100으로 표준화하고 나머지 수확시기별 수량을 상대적 비율로 수정하여 적산온도와의 관계를 검토한 결과 칠보의 백미 및 완전미 수량은 적산온도가 1,100oC가 될 때까지 증가하였으며,증가속도는 적산온도 100oC마다 5% 정도였다. 적산온도1,100oC 이후에는 수량증가는 보이지 않았으나 지나친 수확지연은 품질저하가 우려되므로 칠보의 수확적기는 지역에 관계없이 출수 후 적산온도 1,100 ~ 1,200oC 범위로 판단되었다.

식물체 내에서 HPPD(4-hydroxy phenylpyruvate dioxyge-nase)를 저해하여 카로티노이드 생합성을 억제하는 제초제benzobicyclon 및mesotrione+pretilachlor의 처리 약량에 따른통일형 벼의 약해 발생 정도와 약해발생에 따른 수량영향을조사한 결과는 다음과 같다. 1. Benzobicyclon과 mesotrione+pretilachlor(MP) 처리 후6~12일에 통일형 벼인 한아름벼, 한아름2호, 다산벼는 모두잎의 백화약해 증상이 나타났고, 기준량 처리시 약해는 각각34~64%, 63~75%이었으며, 배량 처리에서는 약해발생이 더심해 각각 76~83%, 83~89% 이었다. 또한 벼식물체는 기준량 처리시 고사되지 않았으나 배량 처리시 식물체 고사율은benzobicyclon은 6.5~11.5%로 MP 2.1~3.3% 보다 고사율이 높았다.2. 출수기는 benzobicyclon 및 mesotrione+pretilachlor처리에 따른 약해로 대조인 butachlor 처리보다 1~2일 지연되었다.3. Benzobicyclon과 mesotrione+pretilachlor 처리시 통일형 벼 생육은 butachlor 처리에 비해 한아름벼, 한아름2호 및 다산벼 모두 기준량 처리시 m2 당 수수가 14~67개가 적고 등숙비율이 2.7~8.6% 낮아져으며 현미천립중이 0.0~1.2g 가벼웠다.4. Benzobicyclon과 mesotrione+pretilachlor 처리시 쌀 수량은 대조인 butachlor처리의 644~725kg/10a에 비해 한아름벼는 5~9%, 한아름2호와 다산벼는 5~8% 감소되었고, 2배량 처리시 수량감소는 더욱 증가하여 한아름벼는 16~28%,한아름2호는 20~24%, 다산벼는 14~23% 감소하였다.

We investigated physicochemical properties of puffed snacks with intermediate and high amylose rice varieties. The intermediate amylose rice varieties ‘Sindongjin’ and high amylose rice varieties newly developed for food processing, ‘Dodamssal’ and ‘Goami4’ were tested for this study. The crude fat and crude protein contents of the rice cultivars ranged 1.47-3.08% and 6.30-7.63%, respectively. The resistant starch and amylose contents of Dodamssal and Goami4 were higher than those of Sindongjin. The hardness of rice was the highest in Sindongjin and Dodamssal. Also, Hardness of puffed snacks decreased by 72.07% for Sindongjin, 88.21% for Dodamssal and 66.67% for Goami4 compared to raw rice samples. The sensory evaluation showed that the highest scores in taste, texture and overall acceptability of puffed snacks were obtained in Dodamssal. The results of this study indicate that Dodamssal was suitable varieties for puffed snacks. Also, the physicochemical properties of Dodamssal were improved by the extrusion process. Therefore Dodamssal can be used for the industrial production of puffed snacks.

Rice flours from five rice (Oryza sativa L.) varieties with different amylose content were prepared by both wet and dry milling processes. The moisture content of wet-milled rice flours (WMR) was approximately three-times higher than that of dry-milled rice flours (DMR). Water absorption index (WAI), water solubility index (WSI), and swelling power (SP) increased in proportion to temperature. The WAI, WSI and SP values of DMR were higher than those of WMR. Baeokchal (BOC), which is a waxy rice cultivar, had a significantly high WSI value. Pasting properties of DMR, except for the BOC cultivar, resulted in an increase in peak, trough, final, and setback viscosities. The levels of resistant starch in four cultivars, except for Dodamssal (DDS), were under 1%, irrespective of the milling process, whereas the resistant starch contents of DMR and WMR in DDS were 9.18% and 6.27%, respectively. In vitro digestibility of WMR was higher than that of DMR, and the estimated glycemic index of the rice flour varieties ranged from 57.6 to 81.3. Damaged starch content of WMR was less than that of DMR; in addition, a negative correlation was observed between the amylose and damaged starch contents of WMR. These results suggest that the properties of rice flour vary depending on the milling method and flour variety, and could be a reference for selecting the appropriate processing method.

To fit the market demands for functional rice such as black and red color rice, ‘Sugary’a high free sugar content line was backcrossed to the black rice ‘Milyang152. The pedigree method was adapted in selection and generation advance. A high polyphenol content line, YR19646-3-2-1-1-2-2 showing red pericarp was selected and designed as ‘Milyang234’ followed by variety name ‘Geonganghongmi’ in 2010. Heading date of ‘Geonganghongmi’ was Aug. 19, medium-late maturing cultivar. ‘Geonganghongmi’ showed resistance to leaf blast and rice stripe virus while susceptible to major diseases and insects. The total polyphenol content of ‘Geonganghongmi’ was high as much as 24.2mg/g compare to that of 4.9mg/g of ‘Nampyeongbyeo’ and 17.2mg/g of a red pericarp rice ‘Jeogjinju’ at 70% ethanol extraction conditions. In local adaptability tests, yield of ‘Geonganghongmi’ was 4.5MT/ha about 86% of ‘Nampyeongbyeo’ and 102% of ‘Jeogjinju’, respectively. ‘Geonganghongmi’ is suitable for southern and middle plain area of Korea.

The amylose contents of rice determine eating quality which is one of the major traits in rice breeding program. To identify the low-amylose gene of the japonica rice cultivar Baegjinju, genetic analysis was conducted using 200 F2 population derived from a cross between the japonica cultivars, Saeilmi and Baegjinju. Individual F2 plants were classified as wild type (translucent grain) and mutant type (dull grain) based on the grain appearance of brown rice. Two hundred F2 plants were segregated into 155 wild type plants and 45 mutant type plants, which fit the 3:1 ratio (x2 = 0.667, df = 1, p = 0.414) and this result indicated the low-amylose gene of Baegjinju is a single recessive gene which controls the amylose contents. Linkage analysis was conducted to localize the low-amylose gene of Baegjinju and fine mapped within an 800-kb interval between 17.5 to 18.8Mb on short arm of chromosome 10. Co-segregated SSR marker, RM25648 was developed and it could be useful for marker-assisted selection and determination of the genetic resource related with amylose contents in rice breeding.

We investigated the physicochemical properties and starch structure of various rice varieties including 15 colored cultivars. NKHC showed the highest level of protein, lipid, and total dietary fiber levels. Reddish brown rice showed higher lipid content than that in black rice cultivars. Apparent amylose content of waxy and non-waxy colored rice varieties was within the range of 3~5% and 15~18%, respectively. IP exhibited the highest total starch (TS) content, whereas, NKHC and HJJ showed lower TS content than that in other cultivars. Pasting temperature of all colored rice cultivars, except IP, was about 68°C. Peak viscosity of IP, JJJ, Hong, and GGHM showed high values of 138, 130, 128, and 124, respectively. All the colored rice cultivars presented A-type X-ray diffraction pattern and polygonal shapes of starch granules were observed using scanning electron micrographs (SEM). Major groups of amylopectin chain lengths were B (12 < DP ≤ 24) and A (DP ≤ 12). SMHC showed the highest B chain content and the lowest A chain content (P < 0.05). These experimental results provided useful information for scientists and the food industry regarding colored rice starches.

Bakanae (foolish seedling) disease caused by Gibberella fujikuroi creates serious problems in the foremost rice growing countries. This study was conducted to identify new resistance genetic sources to Bakanae disease. Bioassay showed that 11 varieties including Gwangmyeongbyeo, Hawn, Wonseadaesoo, Erguailai etc. were resistant to bakanae disease among 254 rice germplasm. Mismatch ratio between phenotype on bakanae disease bioassay and allele type of RM9, a SSR marker closely linked the bakanae disease resistant QTL, qBK1, were 38.3%. These results suggest that RM9 might be used for selecting qBK1, but it cannot be used for wide range of rice germplasm. Resistant germplasm in this study might be have resistant genes different from qBK1. The eleven varieties resistant to selected in this study will be used to identify new resistant alleles or genes to improve bakanae disease resistance in rice.

Drought caused by global climate change is one of serious problems for rice cultivation. However, it was little reported the impact of drought on rice cultivation in Korea. In here, to assess impact of drought on rice varieties in Korean climate condition, growth characteristics and yield components of rice were compared on irrigated and partially irrigated rice paddy field. First, we have chosen 11 rice varieties including ‘Saeilmi’ and ‘Shindongjin’ which are widely cultivated in Korea. For partially irrigated rice paddy treatment, we have withheld irrigation from 25 days after transplanting and water supply was totally dependent on rainfall for rice cultivation. When we examined early plant height and tiller number of these varieties on partially irrigated rice paddy were reduced 1.6% to 18.4% and 10.4% to 33.1%, respectively, and these reduction rate were highly correlated with yield loss in our experimental conditions. Among rice yield components, panicle number was decreased 10.5% to 30.1% according to rice varieties and reduced panicle number was highly correlated with yield loss. Grain number per panicle, grain filling rate and 1,000 seeds weight did not have correlation with yield loss of rice varieties. These result means that growth stage, especially the tillering stage, is seriously affected by drought on rice cultivation in Korea. And we suggest that ‘Saeilmi’, ‘Ilmi’ and ‘Ilpum’ are good for rice cultivation on drought prone rice field in Korea.

저글루테린 및 저아밀로스 품종인 ‘건양2호’는 ‘중국173 호’와 ‘주남벼’를 각각 모본과 부본으로 인공교배 후 집단육 종법을 통하여 육성한 기능성 품종이다. ‘건양2호’의 출수기 는 영호남 및 중부평야지 보통기 보비재배에서 8월 10일로 ‘남평벼’보다 5일 빠른 중생종이다. 간장은 65 cm로 내도복 성이며, 불시출수와 수발아는 안되는 편이고 내냉성은 ‘남평 벼’와 비슷한 편이다. 잎도열병 밭못자리검정에서 중정도 저항성을 보였으며, 줄무늬잎마름병과 흰잎마름병(K1, K2, K3) 에는 저항성이다. ‘건양2호’의 아밀로스함량은 11.5%로 메벼 와 찹쌀의 중간형태로 불투명한 저아밀로스 품종이며, 단백질 함량은 6.0%로 ‘남평벼’보다 약간 낮으며 소화성 전분인 글 루테린 비율이 63.1%로 ‘남평벼’의 73.8%보다 낮다. ‘건양2 호’의 쌀 수량성은 4.61 MT/ha로 ‘남평벼’보다 9% 감수되었 고, 적응지역은 영호남 및 중부 평야 1모작지이다(품종 등록 번호: 제5105호).

Seeds of colored rice generally have high anthocyanin and flavonoid content but some cultivars have low seed germination rate. This defect poses unstable seedling establishment in nursery bed. The seed gravity variations of 10 colored rice varieties and its effect on germination, seed soaking duration and their optimum seeding rates for seedling raising in machine transplanting were investigated in the experiment. Based on seed gravity distribution of the 7 black- and 3 red-colored rice varieties at three levels of seed gravity (1.0<, 1.0~1.06, 1.06>), the black colored seeds such as Josaengheugchal and Sinmyungheugchal had high amount of specific gravity of below 1.0 ranging from 86~ 96%, while they had only 3~13% of seeds in specific gravity above 1.06. Sintoheugmi, Heugjinju, Heugnam, Heugkwang had various mass of seeds, showing 29~44% for specific gravity of below 1.0, 24~39% for 1.0~1.06 and 25~45% for above 1.06. On the other hand, the red colored rice such as Hongjinju, Jeogjinju and Geonkanghongmi had high percentage of specific gravity of above 1.06 with 84~86% while they had only 9~12% of specific gravity below 1.0 similar to Ilmibyeo of noncolored rice. The black colored seed generally showed low germination percentage, slow germination speed and long mean germination time, and low water absorption rate as compared with seed of the red colored rice which was similar to those of Ilmibyeo used as a control cultivar. The black colored seeds took 2~4 days longer seed soaking duration than the red colored rice before germination. This was related to high seed amount of specific gravity below 1.0 in black colored rices. The high amount of seed gravity above 1.06 in the colored rice seeds was positively correlated with percentage of germination, germination speed and mean germination time, ripened grain ratio and water absorption. Seed gravity distribution effect were less pronounced between back- and red- colored seeds in seedling emergence. The black colored rice has slightly lower normal seedling emergence rate than the red colored rice and Ilmibyeo in the seedbed soil due to high percentage of ungerminated seed. Normal seedling emergence rate of the black colored rice in the seedbed was 75.2~82.2% for 10-day old seedling and 85.3~ 90.9% for 30-day old seedling which was lower by 4.5~ 8.0% and 0~3.3%, respectively, than the red colored rice. Based on the normal seedling number per tray of Ilmibyeo for seeding rate of 10-day and 30-day old seedlings, the recommended seeding rate of black colored rice is 200~ 220g seeds for the 10-day old seedling and 110~130g for the 30-day old seedling in transplanting rice while the seeding rate of the red colored rice was 220g seeds for the 10-day old seedling and 130g for the 30-day old seedling.

In here, we screened drought tolerant varieties with modified leaf water loss rate assay and visual drought tolerant phenotype in the greenhouse conditions with more than 800 varieties. Among these varieties, Samgang, Gumei4 and Apo showed the lowest of leaf water loss rate and strong drought tolerant phenotype. To identify drought QTLs with Samgang variety, we developed the doubled-haploid (DH) population consist of 101 lines derived from a cross the drought tolerant cultivar Samgang and the drought sensitive cultivar Nagdong. To score the drought phenotype degrees of this population, we withheld water for 6 weeks and treated the watering for 7 days. After watering, visual phenotype was observed 1 to 9 degree according to the standard evaluation system for rice, IRRI. Drought sensitive parent Nagdong was almost died and was scored as 9 degree, while tolerant parent Samgang showed slightly leaf tip drying phenotype and was scored as 3 degree in our experimental conditions. Three main QTLs were detected on chromosome 2, 6, and 11 with this visual phenotype. We also measured relative water contend of these population under drought stress conditions, and got one main QTL on chromosome 11. The QTL loci on chromosome 11 with flanking markers RM26755-RM287 has a function for visual phenotype and relative water content under drought conditions.

Rice is a staple food crop for more than half of the world population. Severe losses of rice production was caused by various environmental conditions such as cold, heat and flooding annually. Rice is a highly sensitive to low temperature below 15-20 ℃ because of originating from tropical or subtropical climates. Especially, seedling of rice is easily damaged to low temperature and result in seedling yellowing, growth retardation, reduced tillering and yield losses at last. We used a recombinant inbreeding lines (RIL) population of 384 individuals derived from a cross between Hanareum 2, a highly cold sensitive variety and Unkwang, a cold tolerant variety for molecular mapping of QTLs related to cold tolerance. Seedling discoloration of each lines and parents caused by cold response were investigated in field condition after transplanting. And leaf samples of RIL population were collected for evaluation of chlorophyll content using 80% acetone extraction. The seedling of each lines and parents was subjected to low temperate by 5~13 ℃ during 14 days. The cold recovery score (CRS) of RILs was recorded after 4 days recovery period according to standard evaluation system (SES, IRRI). Total of eight QTLs were detected on chromosome 1, 7, 8, 10, 11 and 12 using cold tolerance traits, chlorophyll content, seedling discoloration and cold recovery score in 384 RILs. The qCRS12, which detected on chromosome 12 between two flanking markers id12002113, id12002563 (1.1 Mbp) showed 25 LOD score with 26% of phenotypic variation of cold recovery score in RILs population. The positive allele contributing to cold tolerance came from the cold tolerant parent Unkwang. The result may provide useful information for a marker-assisted breeding program to improve cold tolerant in rice.

눈큰흑찰은 최근 국민의 건강에 대한 관심에 대한 요구에 부응하기 위해 2012년 국립식량과학원 기능성작물부에서 육 성한 품종이다. 눈큰흑찰은 씨눈에 함유된 기능성 물질 함량 이 높은 벼 개발을 목적으로 get를 모본으로 하고 흑찰벼인 조생흑찰 부본으로 교배하여 계통육종법으로 육성되었다. 선 발된 YR25277-B-B-314-2 계통을 밀양263호로 계통명을 부 여하고 2010～2012년 3년간 지역적응시험 실시하여 2012년 12월 농촌진흥청 농작물 직무육성 신품종선정위원회에서 품 종으로 선정되었으며 눈큰흑찰로 명명하였다. 눈큰흑찰의 출 수기는 전국 평균 7월 30일로 조생흑찰과 비슷한 조생종이다. 벼 키는 65 cm로 조생흑찰과 비슷하며 포기당 이삭수와 이삭 당 벼알수도 각각 13개와 73개로 조생흑찰과 비슷하다. 천랍 중이 17.8 g으로 조생흑찰보다 1.7 g 정도 가벼운 편이다. 도 복 및 도열병에는 강하나 흰잎마름병, 바이러스병 및 해충에 약한 편이다. 쌀수량은 3.54 Mt/ha로 조생흑찰의 4.12 MT/ha 보다 낮은 편이다. 현미모양은 장폭비 1.93으로 조생흑찰과 비슷한 중장립형이며 종피에 안토시아닌이 함유된 흑색찰벼 이다. 눈큰흑찰은 거대배 품종으로 씨눈무게가 1.46 mg으로 조생흑찰 보다 3배 정도 무거우며, 이에 따라 씨눈에 많이 포 함된 GABA 함량이 높다. 눈큰흑찰의 적응지역은 중부 및 남 부 평야지이다.

유색 수수인 황금찰수수를 도정할 때 grain과 함께 발생 하는 도정부산물인 hull과 bran의 4가지 용매 추출물의 총 폴리페놀 함량, 항산화 활성, 천연색소 함량과 RAW 264.7 세포주를 이용하여 항염증 활성을 검정하였으며 결과를 요 약하면 아래와 같다. 1. 도정부산물인 hull의 100% 메탄올과 70% 에탄올 추 출물에서 총 폴리페놀 함량이 29.4±0.4와 29.7±0.2 mg GAE/100 g으로 가장 많았고, ABTS 라디컬 소거능(IC50) 이 6.8±0.4, 6.3±0.1 μg/mL로 가장 높은 항산화 활성 을 나타내었다. 2. 총 천연색소 함량에서도 수수 hull의 0.5% 염산 함유 100% 메탄올 추출물에서 322.6±14.5 mg/100g으로 가 장 많은 색소 함량을 나타내었고 hull, bran, grain 모 두의 경우에서 0.5% 염산을 함유한 100% 메탄올을 용매로 추출한 경우에서 가장 많아 수수를 이용하여 천연색소를 추출할 경우 수수 부산물인 hull을 산을 함 유한 메탄올로 추출하였을 때 가장 많은 색소 추출물 을 얻을 수 있었다. 3. 수수 도정부산물과 grain 추출물을 LPS로 NO 생성을 유도한 RAW 264.7 세포에 처리하였을 때, 세포 독성 이 없는 100 ug/mL 농도 이하에서의 NO 생성 억제량 은 hull, bran, grain 추출물의 순으로 나타났고 hull 추 출물의 경우에 농도에 따라 가장 큰 NO 생성 억제를 보였으며 천연색소 화합물 중에서는 apigeninidin의 NO 생성 억제 활성을 확인하였다. 4. 위 결과를 종합해 볼 때, 수수 도정부산물 중 hull은 grain 에 비해 총 폴리페놀 화합물과 천연색소 함량이 높고 항산화 활성과 RAW 264.7 대식세포에서의 NO 생성 량 억제 활성이 우수하여 앞으로 수수 부산물이 항산 화 및 항염증 소재로 가능성이 있음을 확인하였다.

거대쌀눈의 특성과 검정쌀 그리고 찹쌀의 특성을 보유한 눈큰흑찰의 침종과 발아 그리고 기질로 글루탐산을 처리하 였을 경우의 가바를 포함한 주요 성분의 분석 결과는 다음 과 같다. 1. 싹 발아 길이를 기준으로 눈큰흑찰의 가바 함량은 싹 길이가 5~10 mm인 stage-3에 93.9 mg/100 g으로 최 고를 보였고, 대량 제조 조건에서는 최고 126.9 mg의 가바를 함유하고 있음을 확인하였다. 2. 침종에 의한 성분 분석에서는 72시간 침종에서 폴리 페놀, 플라보노이드, 아미노산 그리고 가바 함량이 가 장 많이 축적됨을 확인하였다. 3. 글루탐산 탈탄산효소의 작용에 의한 가바 함량 증가는 현미와 쌀겨 모두에서 급격한 증가가 관찰되었고, 눈 큰흑찰 현미와 쌀겨의 경우 가바 함량이 각각 354.6 mg/100 g과 726.4 mg으로 현미와 쌀겨에 비해 각각 14배와 3배 함량이 증가하였다. 따라서 본 연구에서 눈큰흑찰의 발아와 침종에 따른 품질 특성을 분석한 결과, 뇌의 대사전달 물질의 조정 작용과 고 혈압 그리고 스트레스 조정 기능이 있는 가바의 함량이 침 종과 발아에 의해 일반 쌀에 비해 급격히 증가함을 확인하 였다. 특히나 글루탐산탈탄산 효소의 작용에 의한 눈큰흑찰 의 현미와 쌀겨의 가바 생성은 현재까지 보고된 그 어떤 쌀 품종에서 분석된 가바 함량보다도 가장 우수함을 확인할 수 있어 향후 기능성 발아현미 가공을 위한 원료로 활용이 가 능하며, 침종 조건은 가바 함량이 증진된 밥의 제조에 활용 이 가능하고, 일본에서 시판되는 가바 건강식품의 용량과 맞먹는 함량을 지닌 눈큰흑찰을 이용한 가바쌀 생산과 가바 의 효능에 의한 혈압강하, 체중조절, 알코올 관련 질환 등에 효능이 있는 건강기능성 식품 원료로 활용이 가능할 것으로 사료된다.

새로 개발된 유색미 품종인 중모1020의 왕겨를 이용한 색소의 조성과 함량을 분석하고 생리활성을 검정한 결과, 중모1020의 왕겨로부터 최초로 페튜니딘 색소를 다량함유 하고 있음을 Mass와 UPLC등의 기기분석을 통해 동정하였 다. 중모1020의 색소 조성 중 C-3-G 함량은 29.6%인데 비해 Pt-3-G의 함량이 68.3%를 차지하여 C-3-G 함량이 82.3% 인 기존의 벼 색소의 조성과는 완전히 다름을 보였다. 추출 용매 조건에 따른 분석 결과, 조추출물 수율은 100% 메탄 올에 1.0% HCl을 이용하였을 경우 수율이 11.4%로서 가장 높음을 보였고, 다음이 80% 메탄올에 1.0% HCl용매로 추 출한 경우였다. 안토시아닌 색소 추출량 역시 1.0% HCl을 함유한 100% 메탄올과 80% 메탄올에서 각각 275.0±4.1, 258.0±1.8 mg/100 g으로 가장 많았다. 항산화 활성 비교에 서는 전체 안토시아닌 색소함량이 많고 폴리페놀 추출율이 높은 1.0% HCl을 함유한 80% 메탄올 용매 추출물에서 가 장 항산화 활성이 높음을 보였다.

The global rice reduction due to drought averages 18 Mt, especially, 23 Mha of rice fields in Asia are drought-prone. However, rice breeding programs focusing on drought resistance have made little progress to date. Because proper screening approaches with large scale were not developed to evaluate the drought tolerant degree. In here, we have developed of leaf water loss rate with plastic ware in dark conditions for large screening. Through this bioassay system, we examined drought phenotype degrees of 650 rice varieties. To validate whether this optimized bioassay system is corelated with drought phenotype, we chose 14 varieties having the lowest or highest of the water loss rate. We observed the visual drought phenotype and agricultural traits in green house and field conditions. Apo and Samgang having the lowest of leaf water loss rate showed drought tolerance phenotype, whereas Yeolbaeg and Milyang254 having the highest of leaf water loss rate showed drought sensitive phenotype. Apo displayed proper root length trait and Samgang showed good root dry trait in the greenhouse conditions. These results suggest that a simple screening procedure with water lose rate of leaves is effective to perform large scale screening for drought phenotype in rice.