본 연구에서는 관행의 교배육종과 DNA 마커를 이용한 MAS의 접목을 통하여 벼멸구 저항성과 관련된 단점을 보완하고, 효율적으로 도열병, 줄무늬잎마름병, 흰잎마름병, 벼멸구, 끝동매미충 저항성이 집적된 복합내병충성 우량계통을 육성하고자 수행하였다. 교배모본으로는 완전미율이 높고, 끝동매미충에 저항성인 '남평'과 단간이면서 흰잎마름병에 저항성인 '주남'을 반복친으로 사용하였고, 벼멸구저항성 유전자 Bph1을 가지고 있지만 간장이 크고 재배안전성이 미흡한

Rice is a staple food for more than 50% of the world's population. Embryo comprises only 2 to 3% of the weight distribution of the entire pericarp but has higher concentration of vitamins, proteins, and essential fatty acids than the other parts of grains. Moreover, α-tocoperol, γ-oryzanol, phytic acid and γ-aminobutric acid that have nutraceutical value are abundant. Increasing the volume of embryo assures the fortification of nutritional value of rice grain. We developed new black waxy giant embryo rice, Milyang 263 by crossing Josaengheugchal, a black waxy rice variety, and get, a giant embryo mutant generated by tissue culture. The nutrient contents and physical properties of Milyang 263 were compared with several giant embryo mutants and normal embryo rice varieties. Changes in the nutrient properties after germination were also observed. Results indicated that this new black waxy giant embryo rice, Milyang 263, offers a promising source for improving nutritional quality of rice especially anthocyanin, essential minerals, and GABA.

To investigate a comparison of rice yield and quality between organic and conventional cultivation, study for occurrence of rice diseases carried out in rice (Oryza sativa L.) field of Noahn and Bannam region. The results obtained as following: 1) Bactericide and insecticide were applied twice and four times at Noahn and Bannam region in conventional cultivation (C.C) of rice field, respectively, it was applied twice at two region in organic cultivation (O.C). Rice strip virus, leaf blast, neck blast, sheath blight, bacterial leaf blight, rice water weevil, rice leaf folder, and plant hoppers were occurred mainly in rice field. Leaf blast, neck blast, and rice leaf folder were occurred highly at O.C compared with C.C. 2) Growth level of rice in clum and panicle length was lower at O.C than C.C. Number of panicles per hill was by 0.6 higher at O.C than C.C. Number of panicles per hill was by 0.6 higher at O.C than C.C in Noahn region. Number of spikelets per panicle, grain filling ratio, brown/rough rice ratio, and weight of 1,000 grains was lower at O.C than C.C. Number of panicles per hill was by 0.8 lower at O.C than C.C in Bannam region. Number of spikelets per panicle and grain filling ratio was higher at O.C than C.C while brown/rough rice ratio was lower at O.C. Total yield percentage of rice in O.C was level of 84% at Noahn region and 94% at Bannam region compared with C.C. 3) Head rice percentage was lower at in O.C than C.C at two region. Protein and palatability (Toyo value) were lower at O.C than C.C in Bannam region causing occurrence of neck blast and rice leaf folder by oversupply of nitrogen fertilizer. Protein, whiteness, and palatability (Toyo value) were adequate level at O.C in Noahn region by lower nitrogen fertilizer.

Until now many strategies have been used to produce marker-free transgenic plants such as co-transformation with negative selectable markers, site-specific recombination system, transposable elements mediated transformation, and etc. In this research, embryogenic calli induced from japonica rices, Ilmibyeo and Dongjinbyeo, were tranformed with the vector which simultaneously constructed with cre/loxP and argE genes in T-DNA. Transformation efficiencies were comparably lower than those of our previous studies, since the constructed genome size was relatively big (>10Kb). For eliminate the transformed tissues which contained positive selectable marker gene, tunicamycin was treated at regeneration and selection stages, since cre recombinase gene is expressed under the presence of this antibiotics. The plants were selected first under 50 mg․L-1 hygromycin at 28℃ for 2 weeks after the Agrobacterium-infection at 25℃ for 7 days. And then, the regeneration plants were successfully obtained on MS basal regeneration medium containing 0.1 mg․L-1 tunicamycin. The regenerated plants are now acclimatizing in greenhouse and molecular analysis are currently accomplished with these plants.

An unbalance of rice productions and consumptions caused serious problems in both of agricultural area and grain market of korea. In recently, various efforts for rice processing products such as rice noodles and rice wines are in progress to overcome the unstable rice market. Among them, waxy rice is predominant items in processing rice. However, varietal features of starch viscosity are not considered in the processing industries and rice breeding field. In this study, 12 waxy rices and 2 cultivars Ilmibyeo(japonica) and IR72(Indica) were studied for physicochemical and amylogram to characterize the use of waxy rices. The amylose contents of waxy rices were from 7.1 to 8.1% with soft gel consistency and relatively low alkali digestion value(1.4% KOH) compare to Ilmibyeo. In the amylogram analysis(RVU) of waxy rices, unlikely normal rices, very fast peak time(about 3.5 min.) was obtained compare to that of 6.2 min. of Ilmibyeo. And 2 to 3 groups were classified based on peak viscosity and consitency of RVU. Wangchal, Odorokimochi and Hangangchal showed relatively high peak viscosity seemed not suitable for rice cake due to the hardness speed. And most of waxy rices developed in korea were believed to be suitable for oil fried cakes(Hankwa) because of a certain grade of starch degradation speed. And Mochiminori and Midoromochi originated from japan could be a good sources in waxy rice breeding program to improve the cooking properties especially in slow down of hardness speed with very low peak viscosity, hot viscosity and cool viscosity.

Somaclones regenerated from seed-derived callus culture of a rice cultivar, 'Ilpum', were evaluated for the agronomic and morphological characteristics. A total of 424 plants regenerated and the seeds collected from 297 lines were used for further analysis on morphological and agronomic traits. The results indicated that 21.5% (64 lines) of progenies showed significant differences from the donor cultivar 'Ilpum'. Somaclonal variations were induced leaf character, plant height, grain characters, heading date, and sterility. Among the variants, 8% (24 lines) of sterility, 1.4% (4 lines) of dwarf/semi dwarf, 1.7% (5 lines) of opaque, and 1.3% (4 lines) of leaf-rolling phenotypes were observed. The highest frequency of somaclonal variation was observed on heading date which occupied 9.1% (27 lines) of the entire lines included 6.4% (19 lines) of early heading and 2.7% (8 lines) of late heading. These results suggest that the somaclonal variation will be one of the promising genetic resources due to its wide variation and comparatively high frequency of mutation.

Rapid extension of genomic database leads to the remarkable advance of functional genomics. This study proposes a novel methodology of functional analysis using 5-methyltrytophan (5 MT) mutant together with their 2-DE analysis and public microarray database. A total of 24 proteins was changed in 5 MT mutant and four remarkably different expressed proteins were identified. Among them, three spots were converted to Affymetrix probe. A total of 155 microarray samples from Gene Expression Omnibus (GEO) in NCBI was retrieved and followed by constructing gene co-expression networks over a broad range of biological issues through Self-Organising Tree Algorithm. Three co-expressing gene clusters were retrieved and each functional categorization with differential expression pattern was exhibited from 5 MT resistance mutant rice. It was indicated new co-expression networks in the mutant. This study suggests that on investigating possibility which correspond 2-DE to microarray database with their full potential.

IL-34 (NIL) developed by introgressing chromosomal segment substitution from an accession of Oryza minuta (2n=48, BBCC, Acc. No. 101141) into the O. sativa subsp. japonica cv. Hwaseongbyeo, showed significantly higher number of spikelets per panicle (SSP) than the recurrent parent Hwaseongbyeo. QTL analysis in F2 generation derived from the cross between IL-34 and Hwaseongbyeo revealed that ssp7, a QTL was located in the pericentromeric region of chromosome 7. The frequency distribution of spikelets per panicle followed 3:1 ratio for single locus segregation. The additive effect of the O. minuta allele at the QTL was 23 spikelets per panicle, and 43.6% of the phenotypic variance could be explained by the segregation of marker RM21596. To clarify whether ssp7 could be dissected genetically, we carried out fine-scale mapping with 3,700 F2 plants derived from the cross between IL-34 and Hwaseongbyeo using markers flanking spp7. 186 F2 plants having informative recombination breakpoints within the region flanked by two SSR markers RM500 and RM21615 were identified and used for fine mapping of ssp7. ssp7 was mapped between the SSR markers RM21596 and RM418 which was approximately 441kb in length based on the physical map of the region. Of great interests, the QTL region also had effects on primary branch number (PB), grains per panicle (SP) and grain yield (YD). These results are very useful for transferring or pyramiding ssp7 by molecular marker assistant selection in rice breeding programs.

In rice, tillering is an important trait determining yield. To study tillering at the agricultural and molecular aspects, we have examined a spontaneous rice mutant that showed reduction in the number of culms. The mutant was derived from a F6 line of the cross of Junambyeo*4 / IR72. It could produce, on average, 4 tillers per hill in the paddy field while wild-type plants usually have 15. Except the reduced culm numbers, they also show pale green phenotypes. The phenotypes of this mutant were co-segregated as the monogenic Mendelian ratio (χ2 = 0.002, p = 0.969). In order to locate a gene responsible for the rcn phenotype, the mutant with the japonica genetic background was crossed with Milyang21 of the indica background. Bulked segregant analysis was used for rapid determination of chromosomal location. Three SSR markers (RM551, RM8213, and RM16467) on chromosome 4 were genetically associated with the mutant phenotype. Each of the 217 F2 plants was genotyped with simple sequence length polymorphisms. The data showed that RM16572 on chromosome 4 was the closest marker that showed perfect co-segregation among the F2 population. We suggest the new rcn gene studied here name as rcn10t because there was no report which exhibit a rcn phenotype with a pleiotropic effect of pale green (chlorophyll deficiency), and mapped at same position on chromosome 4.

Many important traits have been tagged allowing plant breeders to apply marker assisted selection (MAS) in rice. PCR itself is simple to set up, and requires little hands-on time. However, a crucial limiting step of MAS programs is the reliable and efficient extraction of DNA which can be performed on thousands of individuals. In this study, We describe a modification of the DNA extraction method, in which cetyltrimethylammonium bromide (CTAB) is used to extract DNA from leaf tissues for suitable MAS in rice. We followed the standard 2% CTAB extraction method in all the procedure. In addition we used the 1.2 ml 8-strip tube instead of 1.5 ml E-tubes to fit the 8-multichannel pipette and employ the 96 well plate to use the swing bucket centrifuge. Our modified CTAB DNA extraction method offers several advantages with respect to traditional and simple methods. 1) adult leaf samples collected in paddy field are applicable. 2) 96 leaf samples can be homogenized only one-time by using tungsten carbonate bead and 96well block. 3) semiautomatic loading method using 8-multichannel pipette from DNA extraction to electrophoresis of PCR products. 4) our system can extract about 400 leaf samples per day by only one technicion. Therefore, this method could be useful for marker assisted breeding in rice.