Total phenolic content, total anthocyanin content and antioxidant activity were analyzed from rice samples collected in Korea, Japan and China. The results showed that the total phenolic content and free-radical scavenging activity differed significantly in these rice lines. The correlation between content and activity was subsequently investigated. The results showed that in black rice, anthocyanin was the major phenolic component and that both phenolic content and anthocyanin content were closely correlated with free-radical scavenging activity. Reverse Phase High Performance Liquid Chromatography (RP-HPLC) data showed that cyanidin-3-O-glucoside and peonidin-3-O-glucoside composed about 90% of the total anthocyanin content in black rice and in red rice. In the red rice extract, the total phenolic content produced a high correlation coefficient with antioxidant activity but correlated very poorly with the total anthocyanin content. The OD458 and the OD500 values which represent the proanthocyanidin content of the rice extract, produced high correlation coefficients with antioxidant activity and total phenolic content. These results suggest that the OD458 and the OD500 values can be used to evaluate the quality of red rice. In addition, based on the data obtained, a competitive accumulation model of anthocyanin and proanthocyanidin in black and red rice was proposed.

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.

In the previous study (Yuan et al. 2009), a quantitative trait locus (QTL) for grain weight was detected on the short arm of chromosome 5 using an advanced backcross lines (BC3F3) between Hwayeongbye (Oryza sativa) and W1944(Oryza rufipogon Griff.) .For detection of gw5 locus, a line CR6 (BC3F4) was selected and crossed to Hwayeongbyeo produce S1F2 and S1F3 population. And a plant from S1F3 population, carried W1944 homozygous segment for target region at gw5 was crossed to Hwayeong to produce S2F2 population. All these population including some S1F3 lines were grown in the field in 2007, 2008 and 2009, respectively (fig1). Frequency distribution of grain weight followed the Mendelian ratios(3:1) for single locus segregation (Χ2=1.22, 0.76, 1.34 in 2007, 2008 and 2009 respectively).In Hwayeongbye genetic background, the W1944 allele at the gw5 locusde creased grain weight, QTL analysis showed that gw5 co-segregated with RM18003 and RM194 (R2=62.7, 69.5 and 37.1% in 2007, 2008 and 2009 respectively). Addition, five QTLs plant height, culm length, secondary branch, spikelet number perplant and rationing ability were detected in the region around gw5, in 2008 and 2009. Substitution mapping with 32F3 lines, gw5 QTL was flanked by two SSRmarkers, RM18003 and RM194, in a300kb to 1.7Mb physical distance region,. QTL analysis indicated that 5 others QTLs plant height, culm length, secondary branch, spikelet number per plant and rationing ability were tightly linked.

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.

Global warming means not only increase in average air temperature but also increase in frequency of extreme weathers such as extremely high temperature over 45oC. Crops are generally sensitive to high temperature during their reproductive growth stage. This experiment was thus conducted to investgate physiological responses of rice (Oryza sativa cv. Chucheong) and soybean (Glycine max cv. Sinpaldal) to high temperature (HT) stress at their reproductive stage. Rice and soybean were exposed to different degrees of high temperature stress by keeping them in a growth cabinet deisnged to maintain air temperature up to 45oC for at least 5 hours in a day for different durations, 0, 1, 2, 3, and 4 days. HT stress treatment delayed heading and flowering of rice and increased the sterility of its' main panicle with increasing duration of HT treatment; 19.7 43.4, 68.1, 81.5 and 91.1% at 0, 1, 2, 3 and 4 days HT treatment, respectively. Increasing sterility due to HT treatment thus resulted in significant rice yield loss; 5.07 4.27, 4.32, 4.51 and 3.62 g/plant at 0, 1, 2, 3 and 4 days of HT treatment, respectively. Soybean was also significantly affected by HT stress in its pod formation and sterility, particularly along the vertical stem. Increasing pod sterility with increasing HT treatemnt thus resulted in significant soybean yield loss.

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 the previous study, 141 BC3F2 lines from a cross between the Oryza sativa cv. Milyang 23 and O. glaberrima were used to identify favorable wild QTL alleles for yield component traits. In this study, we carried out QTL analysis of four grain morphology as well as four yield component traits using 141 BC3F5 lines from the same cross and compared QTLs detected in two different generations. The mean number of O. glaberrima segments in the 141 BC3F5 lines ranged from 1 to 13 with 2.69 and 5.71 of the average means of homozygous and heterozygous segments, respectively. There was a three-fold difference in the number of QTLs detected for four traits commonly evaluated in two generations (seven QTLs in the BC3F5 vs 21 in the BC3F2 population). The percentages of the phenotypic variance explained by QTLs in the BC3F5 population were similar to or less than those in the BC3F2 population. This is probably due to the difference in the genetic composition of two populations and the environmental effects. The locations of the QTLs commonly detected in both generations were in good agreement except for one QTL for spikelets per panicle. The yield QTL, yd3 was colocalized with the spikelets per panicle, spp3. Yield increase at this locus is due to the increase in spikelets per panicle, because both traits were associated with increase in spikelets per panicle and yield due to the presence of an O. glaberrima allele. Clusters of QTLs for grain morphology traits were observed in two chromosome regions. One cluster harboring five QTLs near SSR markers RM106 and RM263 was detected on chromosome 2. This population would serve as a foundation for development of the introgression line population from a cross between Milyang 23 and O. glaberrima.

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.