• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.31-31
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• 2017

Understanding the mechanism(s) to overcome or prevent seed ageing deterioration during storage is of fundamental interest to seed physiologists. Vitamin E (tocols) is known as a key metabolite to efficiently scavenge lipid peroxy radicals which cause membrane breakdown resulting in seed ageing. However, in rice research this hypothesis has been tested for very few lines only without considering intraspecific variation in genomic structure. Here, we present a correlation study between tocols and seed longevity using a diverse rice panel. Seeds of 20 rice accessions held in the International Rice Genebank at the International Rice Research Institute, representing aus, indica, temperate japonica and tropical japonica subpopulations, were used for tocols analysis (quantification of ${\alpha}$-, ${\beta}$-, ${\gamma}$-, ${\delta}$-tocopherol/tocotrienol by ultra performance liquid chromatography) and storage experiments at $45^{\circ}C$ and 10.9% seed moisture content (sample taken for germination testing every 3 days up to 60 days). To examine interactions between DNA sequences and phenotype, the 700k high-density single-nucleotide polymorphism marker data-set was utilized. Both seed longevity (time for viability to fall to 50%; $p_{50}$) and tocols content varied across subpopulations due to heterogeneity in the genetic architecture. Among eight types of tocol homologues, ${\alpha}$-tocopherol and ${\gamma}$-tocotrienol were significantly correlated with $p_{50}$ (negatively and positively, respectively). While temperate japonica varieties were most abundant in ${\alpha}$-tocopherol, indica varieties recorded 1.3 to 1.7-fold higher ${\gamma}$-tocotrienol than those of other subpopulations. It was highlighted that specific ratio of tocol homologues rather than total tocols content plays an important role in the seed longevity mechanism.

• Journal of Plant Biotechnology
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• 제30권4호
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• pp.369-373
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• 2003

In spite of potential benefits of anther culture, low productivity of plant regeneration in some genotypes; e.g. tonsil and indica rice, is one of the major obstacles for practical use of anther culture. This study was conducted to improve cold shock method and carbohydrate source for increasing the efficiency of anther culture in rice. The most common carbon source, sucrose was replaced to maltose, which has two molecules of glucose. Maltose increased callus induction 1.4-to 1.8-fold higher in japonica rice, 3.2-to 11.6-fold in tongil types and 2.7-fold in indica rice IR50. Callus induction was increased from 0.2％ to 12.5％ in maltose medium compared to the medium supplemented with sucrose plus glucose in indica rice "Tetep". A simple procedure of vacuum packaging of panicles during cold shock treatment prolonged not only anther viability more than 15 days but also increased callus induction more than 2-fold compared to open-air storage (conventional method). Combining of above two methods, callus induction was increased 28 to 56％ in japonica, 13 to 33％ in tonsil type and 12 to 31％ in indica rice. Plant regeneration was increased 14 to 35％ in japonica, 10 to 20％ in tonsil and 4 to 15％ in indica rice, respectively.

• 한국작물학회:학술대회논문집
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• 한국작물학회 1992년도 춘계 학술대회지
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• pp.4-5
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• 1992

• Journal of Crop Science and Biotechnology
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• 제10권3호
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• pp.175-184
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• 2007

Two subspecies, japonica and indica, have been reported in rice, which differ in several ecotypic traits. However, reproductive barriers in hybrid progenies between subspecies have been major obstacles in breeding programs using inter-subspecific hybridization. As the first step to elucidate the reproductive barriers, we developed subspecies-specific(SS) STS markers in this study. A total of 765 STS primers were designed through comparing DNA sequences at every $2{\sim}3$cM interval between japonica and indica rices, which are available at Web DBs such as IRGSP, NCBI, TIGR, and GRAMENE, and tested for subspecies-specificity using 15 indica and 15 japonica varieties of diverse origin. Of them, 67 STS markers were identified as SS STS markers and their subspecies-specificity scores were estimated. The SS markers were dispersed throughout the genome along chromosomes. Of them, 64 SS markers were mapped on an RIL population derived from a Dasanbyeo(indica)/TR22183(japonica) cross. Genomic inclination of RILs was evaluated based on the genotyping with different types of markers. Association test between markers and segregation distortion revealed that segregation distortion might not be the cause of generating SS markers. The SS markers will be applicable to estimate the genomic inclination of varieties or lines and to study the differentiation of indica and japonica, and ultimately to breed true hybrid rice varieties in which desirable characters from both subspecies are recombined.

• 한국식품과학회지
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• 제30권3호
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• pp.502-508
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• 1998

우리나라 쌀로서 계통이 다른 일반계와 통일계 쌀의 취반 및 가공 적성을 이해하기 위하여 취반 중 백미의 수분 흡수 특성과 열수 가용화 특성을 조사하였다. $100^{\circ}C$에서 취반 중 백미의 수분 흡수 속도는 일반계가 $0.43{\sim}0.47m^{-1/2}$이고 통일계가 $0.49{\sim}0.53m^{-1/2}$로서 일반계가 통일계보다 더 느린 속도로 일어났다. 쌀의 취반에 따른 열수 가용화 특성은 가용성 물질 뿐만 아니라 가용성 아밀로오스 모두 통일계 쌀이 일반계 쌀보다 더 빠른 속도로 가용화가 일어났다. 가용성 물질에 대한 가용성 아밀로오스의 비율은 취반 30분 후에 일반계 쌀이 $51{\sim}55%$, 통일계 쌀이 $44{\sim}48%$로서 일반계 쌀이 다소 높았으며, 30분 이전까지는 그 비율이 점차 감소하였으나 30분 이후에는 증가하는 현상을 보였다. 이러한 결과에서 취반 중 백미의 수분 흡수 및 열수 가용화 특성은 취반 및 가공 적성에 영향을 미칠 것으로 생각된다.

• 식물조직배양학회지
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• 제27권3호
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• pp.163-167
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• 2000

벼 약배양에서 식물체 재분화 능력의 품종간 차이와 유전 양식에 대해 연구한 결과는 다음과 같다. ‘일미벼’ 외 46품종의 녹색체 재분화율은 자포니카형이 통일형이나 인디카형보다 높게 나타났고, 동일 품종 생태형간에도 배양 효율은 다양한 변이폭을 나타내었다. 자포니카 품종중에서 ‘일미벼’와 ‘향남벼’는 각각 19.4%와 18.1%의 높은 재분화 능력을 나타내었다. ‘밀양 23호’와 ‘추청벼’가 교배된 F$_2$집단의 녹색체 재분화율은 평균 6.6%로 나타났고 0~33.3%까지 넓은 변이폭을 가지는 연속적인 빈도 분포양상을 나타내었다. 캘러스 형성률과 식물체 재분화 능력에 대해 추정된 광의의 유전력은 각각 72.8%와 82.7%로 추정되었다.

• Plant Breeding and Biotechnology
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• 제5권4호
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• pp.371-389
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• 2017

Supplying sufficient rice to growing populations is a global challenge. Hybrid indica rice varieties exploiting heterosis have increased yields, but inter-subspecific crosses between indica and japonica varieties are hampered by sterility. Examination and genetic understanding of yield heterosis in indica/japonica crosses addressing yield barriers are basic requirements. In this study, QTLs for heterosis of yield traits were identified in indica-japonica recombinant inbred lines (RILs) using a total of 178 RILs originating from Dasanbyeo (indica) ${\times}$ TR22183 (japonica) (DT-RILs) and their backcrossed populations. Nine of sixty-six major quantitative trait loci (QTLs) identified in DT-RILs exhibited heterosis. Heterosis QTLs clustered with other traits on chromosomes 1, 4, and 8, and clusters were conserved between different RILs. The clusters contained several known yield enhancement genes/QTLs. Specific heterotic allele combinations contributed to four major heterosis QTLs, particularly for panicle and spikelet number traits. Heterosis for yield and yield-related traits was explained by the harmonized effects of overdominance, dominance, and epistatic interactions in inter-subspecific breeding populations.

• 한국육종학회지
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• 제41권2호
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• pp.101-105
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• 2009

전 세계에서 광범위하게 수집한 벼 유전자원 320개를 63개의 아종특이적마커로 분석하여 유전자원의 다양성, 유연관계 및 유전집단의 구조분석을 하여 아종특이적마커의 아종판별 효율을 검정하고 아종의 게놈 구성을 검토하고자 본 시험을 수행하였다. 1. 본 연구에서 사용한 63개의 아종특이적 마커는 벼 품종을 인디카와 자포니카 두 아종으로 구분하는데 효과적으로 이용할 수 있었다. 2. 실험에 사용한 320개의 벼 유전자원들은 자포니카군(128개)과 인디카군(178개)으로 나눌 수 있었고 Basmati370, Shennong27 등 14개 품종은 중간형 admixture형태의 품종으로 구분할 수 있었다.

• 한국작물학회지
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• 제22권2호
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• pp.18-22
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• 1977

Germination ability of a japonica and 15 indica$\times$japonica varieties was tested at day/night tempuratures of 25/2$0^{\circ}C$ and 12/12$^{\circ}C$. Germination ability of a japonica variety, "Jinheung" and two indican$\times$japonica varieties. "Suweon ＃251" and "Suweon ＃278" was greater than that of other indica$\times$japonica varieties tested. Germination pattern of varieties was made into 4 groups.ieties was made into 4 groups.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2022년도 추계학술대회
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• pp.220-220
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• 2022

Disproportionating Enzyme 1 (DPE1) is an a-1,4-D-glucanotransferase that cleavages the a-1,4-glucosidic bonds and transfers glucosyl groups. In rice endosperm, it participates in starch synthesis by transferring maltooligosyl groups from amylose and amylopectin to amylopectin. Here, we investigated the haplotype variations and evolutionary indices (e.g., genetic diversity and population structure) for the DPE1 gene in 374 rice accessions representing seven subgroups (wild, indica, temperate japonica, tropical japonica, aus, aromatic, and admixture). Variant calling analysis of DPE1 coding regions leads to the identification of six functional haplotypes representing/occupying 8 nonsynonymous SNPs. Nucleotide diversity analysis revealed the highest pi-value in wild group (0.0556) compared to other cultivated groups, of which temperate japonica showed the most reduction of genetic diversity value (0.003). A significant positive Tajima's D value (1.6330) of admixture highlights sudden population contraction under balancing selection, while temperate japonica with the lowest Tajima's D value (-1.3523) showed a selection signature of DPE1 domestication which might be the cause of excess of rare alleles. Moreover, these two subpopulations exhibits a greater differentiation (F_ST=0.0148), indicating a higher genetic diversity. Our findings on functional DPE1 haplotypes will be useful in future breeding programs, and the evolutionary indices can also be applicable in functional studies of the DPE1 gene.