The effects of UV-B radiation on the seedling growth, carbohydrate metabolism and antioxidants activities of rice (Oryza sativa L.) were investigated under environmentally controlled chamber. Supplementary UV­B radiation reduced dry matter as well as leaf area, there­fore, relative growth rates (RGR) of seedlings were decreased by up to half compared to control. Photosynthetic products such as soluble sugars and starch were rapidly and significantly reduced by within 1 day of enhanced UV-B radiation due to the inhibition and degradation of photosynthetic processes and thylakoid membrane integrity. In our study, nonstructural carbohydrate levels were proved to be a main indicator on UV-B­induced stress. The behavior of SOD, CAT, APX and POD activities was monitored in the leaves of rice seedlings subjected to UV-B radiation. Under UV-B treatments, SOD activity was initially increased, whereas CAT and POD activities were slowly and slightly increased. However, APX activity showed no presumable results with an increase of UV-B dose. In leaves of rice seedlings, supplementary UV-B radiation caused an increase in free putrescine and spermidine, however spermine remained unaltered, although 24-hrs UV-B treatment slightly increased. This result presumes that an excess UV-B dose may induce ethylene biosynthesis (senescence) rather than polyamine biosynthesis (defense).

Rice and weed interference in the paddy field caused by resource competition and allelopathy. Evaluation method of active weed suppressive behavior of rice to weed was developed by eliminating light competition at soil condition. Twenty eight days old rice seedlings (6-7 leaf stage) which was grown at saturated, no drainage pot were clipped above 3~~4cm from the soil surface. Weeds seeded around clipped rice stem, named ratoon seeding screening method, showed varietal suppressive difference to Echinochloa crus-galli, Echinochloa crusgalli var. praticola and Monochoria vaginalis. Potential allelopathic rice varieties, Sathi, AC1423 and PI312777 showed better suppressive activity to weed seedling growth than Nonganbyeo and Keumobyeo. Weed suppression of one plant of rice cultivars could be evaluated by the cell size of 2.5~times2.5cm at rice clipping of seedling 29 days after rice seeding.

In this paper, an INS compensation algorithm is proposed using the accelerometer from IMU. First, we denote the basic INS algorithm and show that how to compensate the position error when low cost IMU is used. Second, considering the ship's characteristic and ocean environments, we consider with a drift as a periodic external environment change which is affected with exact position. To develop the compensation algorithm, we use a repetitive method to reduce the external environment changes. Lastly, we verify the proposed algorithm through the experiments, where the acceleration sensor is used to acquire real data.

Number of nodes and branches are yield component characters whose expression are highly related with many other traits. In this study, a population derived from the cross of ‘Keunolkong’ and ‘Shinpaldalkong’ was evaluated with SSR markers to identify QTLs

We used an amplified fragment length polymorphism (AFLP) analysis, a novel PCR-based technique, to differentiate Xanthomonas oryzae pv. oryzae (Xoo) of Korean races. The 6 strains of Xoo K1, K2, K3 races were tested with 81 AFLP primer combinations to identify the best selective primers. The primer combinations were selected according to their reproducibility, number of polymorphic bands and polymorphism detected among Xoo strains. 18 strains of Xoo K1, K2 and K3 races were analyzed with the selected combinations of primer set. Some primer combinations (Eco R I +1 / Mse I+1) could differentiate Xoo of Korean races that were not distinguished by other fingerprinting analysis. Thus AFLP fingerprinting permitted very fine discrimination among different races.

Bacterial grain rot of rice caused by Burkholderia glumae was examined between weather condition and disease incidence. From 1998 to 2000, average disease incidence was 3.0 ％ without difference in survey regions. However, it was related closely to amount of rainfall that disease incidence higher in 1998 and 2000 to 3.0 ％ and 3.6 ％ respectively than 2.3 in 1999 relatively small volum of rainfall season.

This study compared the levels of North Dakota and South Korean conventional and sustainable farmers’ participation in community organizations. The North Dakota data were collected in 1990 from a sample of 568 farm and ranch operators, and the South Korean data were collected in late 1999 and early 2000 from a sample of 147 farmers through interviews and surveys. The data were analyzed using the SPSS ANOVA computer program. The sustainable farmers in both countries were more likely to participate in community organizations than the conventional farmers. Nevertheless, through this comparative study it was found that some differences between two countries exist due to their different cultural backgrounds. Whereas Americans were oriented more to morality and ethics influenced by church, farmers in Korean were more influenced by civil movements. Whereas the reduced tillage farmers in Americans were more likely to be sustainable farmers, the mixed farmers in Korea were more likely to belong to conventional farmers. While individuals in community organizations focused on the economics of agriculture, sustainable farming and farmers" social participation were social matters, which were used to develop sustainable community.