초록 ▼

Ⅳ. 연구개발결과
○ 품종(계통) 육성 및 특허 출원
1. 신품종 및 우수계통 육성
○ 생산성 검정을 포함한 주요 작물학적 특성이 우량한 계통 “화원3호”, “화원6호”를 신품종으로 등재
○ 미질 및 농업적 특성이 대조품종인 일품과 유사하고 도열병 저항성이 증진된 계통을 품종보호 출원 : 화원7호
○ 미질 및 농업적 특성이 대조품종인 화성과 유사하고 미질이 우수한 우량계통 "화원9호“, ”화원10호“ 육성
○ 유전자 고밀도지도 작성 및 집단 육성
- 종자중, 수당립수, 출수일 관여 유전자 고밀도

Ⅳ. 연구개발결과
○ 품종(계통) 육성 및 특허 출원
1. 신품종 및 우수계통 육성
○ 생산성 검정을 포함한 주요 작물학적 특성이 우량한 계통 “화원3호”, “화원6호”를 신품종으로 등재
○ 미질 및 농업적 특성이 대조품종인 일품과 유사하고 도열병 저항성이 증진된 계통을 품종보호 출원 : 화원7호
○ 미질 및 농업적 특성이 대조품종인 화성과 유사하고 미질이 우수한 우량계통 "화원9호“, ”화원10호“ 육성
○ 유전자 고밀도지도 작성 및 집단 육성
- 종자중, 수당립수, 출수일 관여 유전자 고밀도지도 작성 : 화성벼/O. rufipogon, 화성벼/O. minuta, 일품/모로베레칸 조합의 여교배계통(BC₃F₅, BC₄F₅)을 이용.
- 내건성, 내냉성과 같은 스트레스 관여 유전자 고밀도 지도 작성: 밀양23/O. glaberrima, 화성벼/O. rufipogo을 이용하여 분석.
- 중배축 신장성 관여 유전자 고밀도 지도 작성 : 잡초성벼/일품벼의 F_8:9 계통, Nipponbare/Kasalath 조합 NIL 및 F_2:3 계통 이용.
○ 후보 유전자 탐색 및 유전자 분자표지 개발
- 종자중 :　화성벼/O. rufipogon 조합의 gw9 종자중 관여 후보 유전자 탐색 (3 genes) 및 형질전환체 식물체 제작중.
화성벼/O. grandiglumis 조합의 gw2 종자중 관여 유전자와 OsPCR1 유전자의 상호관계 조사 및 특성검정.
- 수량구성요소 : 화영벼/O. rufipogon에서 수당립수 관여 유전자 qspp5, 화성벼/O. rufipogon에서 수당립수 관여 유전자 qspp1 의 후보유전자 탐색.
화성벼/O. minuta에서 출수일 관여 유전자 dth9 관여 후보 유전자 탐색 (1 gene)
- 중배축신장성: Nipponbare/Kasalath 조합을 이용 substitution mapping으로 후보 유전자 탐색 (염색체 1, 3번)
- 내건성, 내염성: 밀양23/O. glaberrima 조합 이용 유묘기, 영양생장기 내건성 우수계통 선발 및 QTL 분석 (염색체 2번)
o 유전자 집적을 위한 근동질계통 간의 교배 및 특성 검정
- 수량 및 수량구성요소: 재배벼/야생벼 3 조합
목표 형질: 1,000립중, 수당립수, 아밀로스 함량, 출수기, 미립 특성 등
화성벼/O. rufipogon 조합의 우수 미질, 생육 계통 선발 및 특성 조사 (YR35)
- 내건성 및 내냉성: 밀양23/O. glaberrima 등 2 조합
- 중배축신장성 : 잡초성벼/일품벼 RIL 계통, Nipponbare/Kasalath 조합 NIL 계통

Abstract ▼

Identification and utilization of trait-improving alleles from Oryza species We generated 55 introgression lines via backcrosses using Milyang23 as the recurrent parent and Oryza glaberrima as the donor. 141 SSR markers were used to genotype 55 introgression lines. The 55 introgression lines with Mi

Identification and utilization of trait-improving alleles from Oryza species We generated 55 introgression lines via backcrosses using Milyang23 as the recurrent parent and Oryza glaberrima as the donor. 141 SSR markers were used to genotype 55 introgression lines. The 55 introgression lines with Milyang23 were evaluated for physiological traits; fresh shoot weight (FSW), fresh root weight (FRW) and dry shoot weight (DSW) under the control and 30% PEG-treated condition. Three lines showing significant difference with Milyang23 were selected for further analysis. Three lines had four, four and two O. glaberrima homozygous segments, respectively. IL9 performed better than Milyang23 in all traits measured in the 30% PEG-treated condition. IL9 possessed four O. glaberrima introgressions on chromosomes 1, 2, 6 and 7. IL12 performed better than Milyang23 in FSW and FRW. IL55 contains two O. glaberrima introgressions on chromosomes 2 and 6. Three lines shared the O. glaberrima segment delimited by markers RM133-RM225 at chromosomes 6. This region corresponds to the QTL region for drought tolerance reported by other previous studies. Although IL9 and IL12 showed improved drought tolerance at the seedling and vegetative stage, they performed poor under the drought stress at the reproductive stage implying that the level of drought tolerance differs according to the growth stage in rice. IL55 had significantly higher no. of the total grain than Milyang 23. This result seems to indicate that IL55 will be a good resource for drought tolerance breeding. The population would be useful in developing drought tolerant lines in the breeding program.
A set of introgression lines carrying wild rice (O. rufipogon) segment in cultivated rice (ssp. Japonica cv. Hwaseong) background were developed based on MAS. 96 ILs were evaluated for agronomic, and germination rate at low temperature. 131 SSR markers were used for genotypic analysis of 96 ILs. 96 ILs and parents were carried out to evaluate the germination rate under low-temperature. The germination rate at 15℃ for 7 days of Hwaseong and O. rufipogon was 33.3% and 98.7%, respectively. Five QTLs for low temperature germinability were identified on chromosomes 1, 3, 4, 10 and 11. The O. rufipogon alleles at all loci detected in this study increased germination rate under low-temperature.
A near isogenic line (BC₄F₁₀) CR572 developed by introgressing chromosomal segment from Oryza rufipogon (Acc. No. 105491) into the O. sativa subssp. japonica cv. Hwaseong, showed significant increase in the number of spikelets per panicle (SSP) and grain weight than the recurrent parent Hwaseong. Quantitative trait locus (QTL) analysis in F₂ generation from the cross between CR572 and Hwaseong revealed that two QTLs, qSPP1 and qTGW1 were linked to SSR marker, RM283 on chromosome 1. The additive effect of the O. rufipogon allele at qSPP1 was 13 spikelets per panicle, and 21.6% of the phenotypic variance was explained by the segregation of RM283. qTGW1 explained 19.1% of the phenotypic variance for grain weight. Substitution mapping was carried out with five F₃ lines derived from F2 plants having informative recombination break points within the target region. Substitution mapping indicated the linkage of qSPP1 and qTGW1. CR572 yielded 18.2 and 15.8% more than Hwaseong at two locations, respectively mainly due to the increase in TGW and SPP. These results are very useful for transferring the QTL cluster by molecular marker assisted selection in rice breeding programs and for cloning the QTL genes by map-base cloning.
In our previous study, one putative quantitative trait locus (QTL) for days to heading, dth9 was detected near the SSR marker RM215 on the long arm of chromosome 9 from an advanced backcross line, WH29001, developed by introgressing chromosomal segments from an accession of Oryza minuta (2n=48, BBCC, Acc. No. 101141) into the O. sativa ssp. japonica cv. Hwaseongbyeo. To clarify whether dth9 could be dissected genetically, we carried out fine-scale mapping with 1,340 F₂ plants derived from the cross between a nearly isogenic line (NIL) IL-25 plant which was homozygous for the O. minuta DNA in the target region RM5661 - RM24730 on chromosome 9 and Hwaseongbyeo. Frequency distribution of days to heading followed a 3:1 ratio for single locus segregation. The phenotypic variation explained by this QTL was 58%. Fifty-three F₂ plants having informative recombination breakpoints within the region flanked by two SSR markers RM5661 and RM24730 were identified and used for fine mapping of dth9. dth9 was mapped between two SSR markers, VNR10 and RM215 which were approximately 76-kb in length based on the physical map of the region. The awn9 related to awn length was also located in the same interval, and these results seem to indicate that QTLs for awn length and days to heading are tightly linked. The QTL dth9 had been detected in the previous QTL studies from interspecific crosses, indicating that is heading date QTL is conserved among wild species of rice .
In this study, IL28, which is a near isogenic line (NIL) developed by introgressing chromosomal segments of the cultivar ‘Moroberekan’ into the cultivar ‘Ilpumbyeo’, showed a significant increase in the number of spikelets per panicle (SPP) and 1,000-grain weight (TGW) compared to the recurrent parent, Ilpumbyeo. Quantitative trait locus (QTL) analysis in 243 F2 plants derived from a cross between IL28 and Ilpumbyeo indicated that both qSPP6 and qTGW6 are located in the interval RM3430–RM20580. Following substitution mapping with 50 F_3:4:5 lines, qSPP6 was mapped to a 429-kb interval between RM20521 and InDel-1, while qTGW6 was mapped to a 37.85-kb interval between InDel-1 and SNP-3, based on the japonica genome sequence. This result indicates that qSPP6 and qTGW6 are different genes. Yield trials with substitution lines indicated that lines harboring the homozygou Moroberekan segment at both the qSPP6 and qTGW6 regions howed significantly higher grain yield compared to Ilpumbyeo.
Because the Moroberekan alleles for SPP and TGW have been shown to be beneficial in the genetic background of Ilpumbyeo, both the qSPP6 and qTGW6 alleles might prove valuable in improving rice yields. Closely linked SSR markers are expected to facilitate the cloning of genes that underlie these QTLs, as well as with marker-assisted selection for variation in SPP and TGW in rice breeding programs.
Grain weight (GW) is one of the most important targets for grain yield in rice breeding. In previous studies, two quantitative trait loci (QTLs) for grain weight (GW), tgw2 and gw8.1, have been identified using progeny derived from crosses between the japonica cultivar Hwaseong and Oryza grandiglumis, and Hwaseong and O. rufipogon (IRGC 105491), respectively. The wild alleles increased GW at two loci. An F₂ population (186 plants) was developed by crossing two near isogenic lines (NILs) harboring tgw2 and gw8.1 to test their interaction. Simple sequence repeat (SSR) markers tightly linked to two QTLs were used to check the genotype of the F₂ population and to select four F₃ QTL-NILs with a combination of two QTLs. 186 F₂ plants were classified into 9 groups based on their genotype at two loci, tgw2 and gw8.1. Two-way ANOVA revealed no interaction between 2 QTLs in the F₂ population. 1,000 grain weight (TGW) of homozygous plants with wild alleles at two loci was significantly higher than that of plants with a single QTL in the F₂ and F₃. These results indicate that two QTLs act additively in distinct or complementary pathways in controlling grain weight. Based on the result it is desirable to pyramid two QTLs into a single line since the double-QTLs line gave further advantage in increasing TGW in the Hwaseong background.
In direct-seeding cultivation of rice, the emergence and establishment of seedlings are important for determining the actual yield. These traits depend principally upon elonation of both the mesocotyl and coleoptile. Mesocotyl elongation in rice is controlled by several genetic factor. in this study, we mapped QTL for mesocotyl elogation using F8 line form a cross between the cultivated rice, Ilpumbyeo and a weedy rice, PBR. One of the Korean weedy rice, PBR showed the long mesocotyl length than that of cultivars, Ilpumbyeo under agar media condition. After a phenotyping of 150 F7 lines for mesocotyl length, a subset of 20 lines selected from the two extreme phenotypic tails was used for the bulked segregant analysis. Two QTL were detected on chromosome 1 and 3. These two QTL were confirmed using 120 F8 lines. Two QTL, qMel-1 and qMel-3 on chromosomes 1 and 3 accounted for 37.3% and 6.5% of the phenotypic variance, respectively. In our previous study, a total of five QTLs for mesocotyl length were identified on chromosomes 1, 3, 7, 9 and 12 in backcross inbred lines from a cross between Nipponbare and Kasalath under agar condition. Notably, the QTLs for mesocotyl length were commonly mapped on chromosomes 1 and 3 in different parent crosses and experiment conditions. These results clearly showed the existence of QTLs controlling mesocotyl elongation on chromosome 1 and 3. Moreover, to fine map the two QTLs, a cross was made between 2 chromosome segment substitution lines (CSSL-6 and CSSL-15), each harboring the Kasalath allele across the qMel-1 and qMel-3 region. in F2 populations, two near isogenic lines (NIL) were selected with the following genotypes: NIL-1 (Nipponbare homozygous at qMel-1 and qMel-3 loci) and NIL-2 (Kasalath homozygous at qMel-1 and qMel-3 loci). To find predicted genes controlling mesocotyl elongation, we analyzed gene expression profiles of NIL-1 NIL-2by microarray. A total of 194 cDNAs out of 29,389 unique genes showed changed more than 2 folds in coleoptile tissue of NIL-2. Coleoptile tissue including mesocotyl part were collected from seedling incubated for 4days in darkness. From the gene ontology analyses of the expression profiles, the 28 and 52 genes from up- and down-regulated genes, repectively have orthologues in Arabidopsis genes. The analysis with GOMINER (http://www.geneontology.org/, http://discover.nci.nih.gov/gominer/) showed the genes involved in the 1 and 2 of biological processes and molecular function, respectively, in a comparison NIL-1 and NIL-2. In molecular function category, genes involved in amylase activity were down-regulated. In further study, we need to characterize the functional roles of nominated genes including genes related amylase activity.