재래벼와 잡초벼 등 국내 고유 유전자원을 밥쌀용 벼 품종 개발에 활용하기 위한 기초자료를 얻기 위하여 전분 호화특성 분석과 함께 식미 관련 물리·화학적 특성의 연차 간 변이를 분석하여 환경 변화에 대한 안정성을 검토하였다. 1. 76개 유전자원을 이용하여 전분 호화특성 및 식미관련 특성에 대한 조사를 연차간 수행하여 그 변이를 상관분석으로 비교한 결과 고도로 유의한 상관관계를 확인하였다. 2. 수집 특성에 따라 유전자원을 4그룹으로 나누고 조사항목의 연차간 평균값을 비교한 결과 상관계수와 관계없이 기상 변화에 따라 항목별로 연차간 유의한 차이를 확인하였다. 3. 호화특성 기반의 군집분석 결과 76개 자원이 6개의 그룹으로 각각 분류되었으며, 약 55% 이상의 유전자원이 III, IV 그룹에 분포되었고, 국내 품종(C그룹)과 국내 잡초벼(B그룹) 유전자원의 경우 군집분석결과 5개의 그룹에 걸쳐 가장 넓게 분포하였다. 4. 전분 호화특성 및 식미특성을 기준으로 밥윤기치가 높았던 국내 재래벼 2품종(왜도와 구도)과 국내 잡초벼 3품종(달성앵미10-2, 남제주앵미6, 완도앵미6) 우량품종으로 선발되었다. 5. 특히, 완도앵미6의 경우 밥윤기치 평균 값이 85.1로 매우 높았으며, 이화학적 특성 등이 수광 수준으로 양호하였는데, 이는 국내의 고유 유전자원으로부터 우수한 자원을 확보하여 유용 유전자를 도입하는 육종연구에 활용가치를 높일 수 있을 것으로 생각된다.

본 연구는 국내 잡초벼인 완도앵미6의 식미관련 유용인자를 자포니카벼 품종에 도입하여 식미가 개선된 새로운 품종을 개발하기 위한 기초 육종연구로 수행되었다. 식미개선을 위하여 국내 자포니카 벼 품종인 화영과 윤기치가 우수한 국내 잡초 벼인 완도앵미6를 교배하여 재조합 자식계통을 육성하였으며 이 조합으로부터 고품질 품종 개발에 활용 가능한 우량계통을 육종에 이용하고자 수행한 결과는 다음과 같다. 1. 화영과 완도앵미6 조합의 교배립을 생산하여 SSD법으로 8세대까지 계통전개 하였으며 초형 등을 고려하여 최종 224계 통의 RIL을 육성하였다. 2. 육성된 RIL집단의 주요 농업특성 특성을 3년(2016-2018) 간 평가하여 연차간 변이를 확인하였으며, 육성된 집단으로부터 작물학적 특성과 식미관련 특성이 우수한 10계통을 선발하였다. 3. 선발된 계통에 대한 아밀로스 함량, 단백질 함량, 알칼리 붕괴도 등의 이화학적 특성을 분석하였는데, 특히 선발된 계통 모두가 수여친인 완도앵미6의 수준에서 윤기치가 개선된 것을 확인하였다. 4. 식미와 관련이 높은 것으로 알려진 밥의 질감과 관련하여 관능평가와 기계적 물성 측정값에 대한 비교에서 두 방법 간에 상관이 확인되지 않아 이에 대한 보완 연구가 필요할 것으로 사료된다.

Rice cultivation by direct seeding allows reduced labour and production costs in addition to other benefits. However the success of this rice production method can be limited by uneven fields with poor drainage or heavy rainfall at sowing leading to early flooding conditions slowing germination and hindering crop establishment. Hence, the need to improve tolerance to anaerobic conditions in both rainfed and irrigated rice ecosystem after direct seeding. In this study QTL analysis was performed to identify QTLs associated with tolerance derived from Vietnamese variety Tai Nguyen (TN) under anaerobic conditions during germination. The population derived from a cross between TN (tolerance indica lines) and Anda (susceptible japonica), was used for collection of phenotypic data based on the survival rates of the seedlings at 21 days after sowing under 10cm of water. A total of 286 F2:3 families of the population were used for QTL mapping and the genotyping was carried out with the infinium 6K SNP-chip based on the illumina infinium platform. Two significant QTLs associated with the AG trait were detected on chromosomes 1 and 11, respectively. In Particular, the QTL on chromsome 1 had an LOD score of 7.45 and R2 of 14.21%. We plan to confirm the identified QTLs in further studies and develop varieties with improved anaerobic germination ability using advanced backcross lines.

Bacterial blight (BB) of rice, caused by Xanthomonas oryzae pv. oryzae (Xoo), is a significant disease in most rice cultivation areas. The present study was performed to identify new BB R-gene conferring resistance to Korea Xoo isolates, derived from IR65482-7-216-1-2 and to construct a physical map of the candidate gene. An F2 population derived from a cross between 11325 and Anda was used to determine the exact position of the nearest recombination event to the target region. The position of the R-gene was delimited by flanking markers, RM1233 and RM5766, on chromosome 11. Of the 56 markers designed in the flanking region, 20 were selected as anchor markers and the R-gene was mapped to a 295kb region on chromosome 11. To narrow down the interval spanning the R-gene, an additionally SSR marker, 20 STS markers, and CAPS marker between RM27320 and ID55.05-79 were developed using rice reference genome information. From the result the gene was defined by RM27320 and ID55.WA18-5 located in the BAC clone OSJNBa0036K13. The physical distance between these two markers is approximately 80kb. In a further study, gene expression analysis against listed candidate genes was investigated using semi-quantitative transcription PCR. These results will useful for future disease breeding as well as gene function studies regarding resistance genes.

Cold stress at the seedling stage is a major threat to rice production. Cold tolerance is controlled by complex genetic factors. We used an F7 recombinant inbred line (RIL) population of 123 individuals derived from the cross of a cold-tolerant japonica and a cold-sensitive indica cultivars, for QTL mapping. Phenotypic evaluation of the parents and RILs in an 18/8oC (day/night) cold-stress regime showed continuous variations for cold tolerance or sensitivity. Six QTLs for seedling cold tolerance were identified on chromosomes 1, 2, 4, 10, and 11 with percent phenotypic variation (R2) ranging from 6.1% to 16.5%. Three main-effect QTLs (qSCT1, qSCT4, and qSCT11) were detected in all cold-tolerant RILs which explained high sum of phenotypic variation (SPV) ranging from 27.1% to 50.6%. Two QTLs (qSCT1 and qSCT11) on chromosomes 1 and 11 were fine mapped. The marker In1-c3 from ORF LOC_Os01g69910 of the BAC clone B1455F06 encoding calmodulin-binding transcription activator (CAMTA) and another marker, In11-d1 from ORF LOC_Os11g37720 (Duf6 gene) of the BAC clone OSJNBa0029K08, co-segregated with seedling cold tolerance. These two InDel markers amplified 241-bp and 158-bp alleles, respectively, in cold-tolerant RILs, and in the cold-tolerant donor Jinbu, which were absent in cold-sensitive parent BR29 and cold-sensitive RILs.

The objective of this study was to characterize the main-effect QTLs, epistatic QTLs and QTL-by-environment interactions (QE), which are involved in the control of protein content. A population of 120 doubled haploid (DH) lines derived from a cross between 'Samgang' and 'Nagdong', was planted and determined for protein content over three years. Based on the population and a genetic linkage map of 172 markers, QTL analysis was conducted by WinQTLcart 2.5 and QTLMAPPER. Three main-effect QTLs affecting protein content of brown rice were detected from 2004 to 2006 on chromosomes 1 and 11. The qPC11.2 was repeatedly detected across two years. Seven pairs of epistatic loci were identified on eight chromosomes for protein content and collectively explained 39.15% of phenotype variation. These results suggest that epistatic effects might be an even more important component of the genetic basis for protein content and that the segregation of the DH lines for protein content could be largely explained by a few main-effect QTLs and many epistatic loci.

With the development of diverse agricultures worldwide, biofortified rice noted for its preferable marketability and palatability plays an important role in the world's agricultural economics and rice breeding programs. In this report, several M5 of T-DNA inserted lines derived from the donor cultivars, 'Hwayong' and 'Dongjin', were selected for high or low protein, high lipid and low amylose content, respectively. The coefficients and ranges of variation for the chemical constituents between M4 and M5 T-DNA inserted lines were evaluated in comparison with those of the donor varieties. Results indicated that T-DNA insertion might be an effective way to generate useful variations for chemical composition of rice grains which could be used for the development of biofortified rice cultivars.

본 연구에서는 벼멸구 저항성 개통 육성과정 중에 수행한 PS와 MAS system간의 선발 효율을 정확성, 소요시간, 소요비용 등의 요인으로 비교･분석함으로써 MAS system의 선발 효율을 제시하고, 이를 이용하여 효과적인 MAS system을 구축하고 실용화하기 위한 방안을 제시하였다. DNA marker를 이용하여 벼멸구 저항성 개체를 선발하고 MAS 체제를 확립하기 위하여 ‘삼강/낙동’ 조합의 F2집단, RIL(F6), DH집단, 여교잡집단(BC6F5)을 대상으로 PS와 marker 검정을 병행하여 두 검정 방법 간에 각 잡종집단 및 세대별 저항성과 감수성 계통(개체)의 비율을 비교한 바 95%이상 일치하였다. MAS 체제와 PS간의 선발효율을 비교한 바 MAS는 PS에 비해 약 32%의 비용이 절감되었고, 검정에 소요되는 기간도 기존의 PS에서는 30일인데 비해 MAS에서는 7일로 크게 단축되었다. 이 결과를 바탕으로 MAS에 의한 벼멸구 저항성 계통 선발 체계를 확립 할 수 있었다.

Demand for high quality rice has always been a major factor in the international rice marketing. In the present study, doubled haploid (DH) population derived from anther culture of a Tongil/japonica hybrid was used for genetic analysis of rice grain quality. The average values of DH lines for grain weight, grain length and the ratio of grain length to width were near the mid-parent value. More than 40% DH lines showed transgressive segregation for grain weight, length, amylose and lipid content, but less than 10% DH lines observed on ratio of length to width and grain thickness were transgressive segregation. Correlation analysis between appearance qualities and physicochemical characters indicated that grain width and grain thickness both significantly and negatively correlated to protein and lipid content. A highly significant negative correlation between protein content and amylose content was observed.