• 한국작물학회지
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• 제63권3호
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• pp.219-228
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• 2018

Weedy rice (Oryza sativa) is a semi-wild rice grown in paddy fields and is more adapted to the environment than cultivated rice. Therefore, it is expected that the seeds of weedy rice might contain some chemicals related to its environmental adaptation, such as antioxidants, which may be useful for nutritional and medicinal purposes. This study was carried out to investigate the antioxidant activities of weedy rice compared to a Korean-bred rice cultivar, Sindongjin (SDJ), and to screen lines that show higher antioxidant activity in 199 accessions of weedy rice germplasm collected in Korea. DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity ranged from 31.0 to 91.7%, with an average of 82.5%, and 19 accessions that showed more than 91% antioxidant activity were selected. The 19 accessions were re-screened against non-germinated brown rice (BR) and germinated brown rice (GBR) using four assays, total phenol determination, DPPH radical scavenging, ABTS radical scavenging, and reducing power activities. The results showed that accession 'WD3' had the highest antioxidant capacity in both BR and GBR, suggesting that WD3 is a promising potential source of antioxidants and could be developed as a potentially functional substance material.

• 한국잡초학회지
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• 제30권2호
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• pp.68-83
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• 2010

Weedy rice (Oryza sativa L.) occurred sympatrically with other weeds and the rice crop in Malaysian rice granaries. We conducted field surveys in 2006-2008 seasons in 7 farm blocks of Selangor's North West Project, Malaysia to enlist the new biotypes of weedy rice (NBWR) and assess their spatio-temporal pattern of distribution based on quantitative and dispersion indices. No less than 16 accessions of NBWR were identified based on their special traits, viz. panicle type, pericarp colour, presence or absence of awn, seed type and degree of grain shattering. The NBWR accessions exhibited a combination of morphological traits from open panicle, grain with awns, red pericarp, short grain type, and degrees of grain shattering. Others mimic commercial rices with close panicle, awnless grains, white pericarp, long or short grain-type. Invariably, the NBWRs mimic and stand as tall as cultivated rice namely MR219, MR220, or MR235 and these NBWR accessions stand among equals morphologically vis-a-vis the commercial rice varieties. Most accessions displayed varying degrees of grain shattering in excess of 50%, except Acc9 and Acc12. The seasonal dynamics of on the prevalence of dominant NBWR accessions were also displaying significant differences among farm blocks. While Bagan Terap farm block, for example, did not record any measurable changes in the dominant NBWR accessions over seasons, the Sungai Leman farm block recorded measurable season-mediated changes in the dominant NBWR accessions. Sungai Leman started with NBWR Acc3, Acc4, Acc5, Acc7, Acc8, and Acc12 in season 1 of 2006/2007, but no measurable records of Acc3 and Acc5 were shown in season 2 of 2007. In season 3 of 2007/2008, only Acc8 and Acc12 prevailed in the farm block. In Sawah Sempadan farm block, season 3 of 2007/2008 showed much reduced prevalence of NBWRs leaving only Acc8 and Acc12. Most accessions registered clump or under-dispersed spatial distribution pattern based on quantitative indices: variance-to-mean ratio (VMR) and Lloyd's patchiness values. The dynamics on the extent of infestation and prevalence of dominant NBWR accessions registered both season- and farm-block mediated differences. Most accessions showed VMR >1 thus indicative of having a clump or clustered spatial distribution, as exemplified by Acc3, Acc4, Acc7, Acc8 and Acc12 in all farm blocks throughout three seasons. Some accessions have either random or uniform distribution in a few farm blocks. The Acc8 has the highest population counts based on important value index, followed by Acc12, and both were the most dominant accession while Sawah Sempadan was the worst farm block infested by NBWR compared to other farm blocks. These results were discussed in relation with the current agronomic and weed management practices, water availability and extension services in the granary.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.278-278
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• 2017

Brown rice grains are increasingly attended by consumers due to their potential health benefits of antioxidant capacity. Therefore, this research was carried out to evaluate the antioxidant activity of brown rice in Korea-native weedy rice germplasm. Two hundred and twenty one accessions of weedy rice used in this study were received from the National Agrobiodiversity Center of RDA, and were regenerated in the experimental field of Chonbuk National University. The sampled seeds were extracted using methanol and the extracts were analyzed using the 1, 1-dipheny-2-picrylhydrasyl (DPPH) free radical scavenging assay for antioxidant capacity determination. Among the all germplasm, the samples of seed coat in red colour, white colour, red -white mixing colour and brown colour were 171 (81%), 26 (12%), 12 (6%) and 2 (1%), respectively. The antioxidant activity values of all samples were varied in the range from 22.31% to 95.53 % and mean value was 82.09%. Depend on the seed coat colour, the average antioxidant activity of the extract of weedy rice seeds indicated that the following order in seed coat colour: red colour (89.11%) > the red-white mixing colour (70.67%) > brown colour (53.16%) > white colour (45.99%). The antioxidant activity of red coloured weedy rice were significantly higher than those of the others. It is suggested that Korea-native weedy rice accessions with high antioxidant activity could be developed as a potential functional food material by further research of component analysis.

• Weed & Turfgrass Science
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• 제2권1호
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• pp.15-22
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• 2013

제초제 내성 형질전환 벼와 모본(동진벼) 및 잡초성 벼 두 계통(화성앵미 1과 광양앵미 12)의 표현형질을 비교하였다. 형질전환 벼와 모본의 질적형질은 모두 유사하였지만, 까락의 유무, 지엽 자세 및 종실 색은 형질전환 벼와 잡초성 벼 사이에 큰 차이가 있었다. 양적형질 중에서 초장, 분얼 수 및 지상부 건물중은 형질전환 벼나 모본에 비해 잡초성 벼에서 유의하게 우세했다. 형질전환 벼 및 모본의 주당 종실중과 천립중은 잡초성 벼에 비해 유의하게 무거웠다. 형질전환 벼는 모본 및 잡초성 벼에 비해 탈립이 용이하지 않았으며, 형질전환 벼의 배유 아밀로스 및 단백질 함량은 잡초성 벼와 유의한 차이가 있었다. 이와같은 형질전환 벼와 잡초성 벼 표현형질의 비교 연구는 형질전환 벼의 잡초화 가능성 예측에 활용될 수 있을 것이다.

• 한국육종학회지
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• 제42권2호
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• pp.144-150
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• 2010

The objective of this study was to map gene/QTL for photoblastism in a weedy rice (photoblastic rice: PBR) using DNA markers. Light-induced effect on germination of seeds was compared among three accessions (Oryza sativa L.), PBR, Milyang 23 and Ilpum. Results showed that PBR seeds started to show photoblastism during seed development, different from Ilpum and Milyang 23. Frequency distribution of germination in the F4 lines from crosses between Ilpum and PBR and, Milyang 23 and PBR revealed bimodal distributions suggesting that photoblastism was controlled by a few genes. Bulked segregant analysis using $F_4$ populations derived from the above two crosses was conducted to identify gene/QTL for photoblastism. Two QTL were identified on chromosomes 1 and 12 explaining 11.2 and 12.8% of the phenotypic variance, respectively. Two QTL were further mapped between two SSR markers, RM8260 and RM246 on chromosome 1, and between RM270 and 1103 on chromosome 12. It is noteworthy that two QTL for photoblastism were colocalized with the QTL for seed dormancy reported in the previous QTL studies. The clustering of two genes for photoblastism and dormancy possibly indicates that these regions constitute rice phytochrome gene clusters related to germination. Because PBR has a low degree of dormancy, a pleiotropic effect of a single gene controlling dormancy and photoblastism can be ruled out. The linked markers will provide the foundation for positional cloning of the gene.

• Weed & Turfgrass Science
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• 제7권3호
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• pp.171-179
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• 2018

국내에서 수집되어 농업유전자원센터에 기탁된 잡초성벼 유전자원 중 100점을 이용하여 토양 매몰 깊이, 담수 처리 깊이 및 기간, 생육 온도에 따른 출현율을 분석하고 출현하지 못하고 토양 속에 존재하는 종자를 회수하여 종자 상태를 분석하였다. 토양 매몰 깊이가 1 cm로 얕을 시 담수 깊이 5 cm 및 10 cm 처리에서 출현율이 각각 54, 57% 감소하였으며, 토양 매몰 깊이가 5 cm 깊어지면서 담수 처리에 따른 출현율 감소는 담수 5 cm, 10 cm에서 66, 84%로 크게 증가하였다. 잡초성벼 유전자원 별 담수 처리에 따른 출현율 변화를 분석한 결과, 토양매몰깊이 1 cm 및 담수 깊이 5 cm에서는 대부분의 유전자원이 60% 이하의 출현율을 보였으며, 토양매몰깊이 5 cm 및 담수 깊이 5 cm에서는 출현율은 크게 감소하여 94%의 유전자원이 10%이하의 출현율을 나타내었다. 출현이 완료된 뒤 출현하지 않고 토양 속에 남아있는 종자를 회수하여 종자 상태를 분석한 결과, 토양 매몰 깊이가 5 cm 일 시, 담수 처리에 의해 발아는 하였지만 출현하지 못하는 비율이 증가한 반면 죽거나 소멸된 종자의 비율은 감소하였다. 생육 온도를 달리하여 담수 처리 기간 동안의 유효 적산 온도에 따른 종자의 변화를 분석한 결과, 출현율은 유효 적산 온도와 유의한 상관관계를 보이지 않았으나 종자 사멸율 및 발아/미출현율은 유효 적산온도에 따라 증가, 감소하는 경향이었다. 담수 처리에 따른 출현율 변화는 담수 처리 온도 보다는 담수 처리 기간에 따른 차이가 컸으며 담수 처리 기간이 21일 이상일 시 출현율이 크게 감소하였다.