This study was carried out to investigate the proper interval of water exchange according to nitrogen fertilizer level at medium saline soil which are 0.3 or more soil salinity in southwestern reclaimed saline land. The nitrogen fertilizer level were 14, 17, 20kg per 10a, and the interval of water exchange were every 3, 6, 9 days after transplanting. The summarized experimental results are as follows. The salinity were maintained as low when the interval of water exchange were every 3 or 6 days after transplanting, but salinity was highest at rooting stage, and decreased from that, so salinity were about 0.3 at panicle initiation stage or ripening stage when the interval of water exchange was every 9 days after transplanting. The rice yield were 537-552kg/10a when the interval of water exchange was every 3 days with 17-20kg/10a nitrogen fertilizer level, and 519-533kg/10a when the interval of water exchange was every 6 days with 17-20kg/10a nitrogen fertilizer level, but decreased outstandingly in the other treatments. Considering the yield and salt injury at medium saline soil at southwestern reclaimed saline land, proper nitrogen fertilizer level was 17-20kg/10a when the interval of water exchange were every 3 or 6 days after transplanting.

This study was carried out to investigate the optimum application time of basal fertilization in direct-seeded rice on flooded paddy surface at medium saline soil in southwestern reclaimed saline area which is Munpo series and have 0.3 or more soil salinity. The nitrogen fertilizer level were 14, 17, 20kg per 10a, and the basal fertilization were applied before sowing, 10, 20, 30 days after sowing along with topdressing at tillering stage, respectively. The summarized experimental results are as follows. Seedling stand was proper when basal fertilization was applied before sowing, but lower than appropriate seedling stand when basal fertilization were applied 10, 20, 30 days after sowing along with topdressing at tillering stage. The rice yield were 509-541kg/10a when 14-20kg/10a basal fertilization was applied before sowing, and 368-481kg/10a when basal fertilization were applied 10, 20, 30 days after sowing along with topdressing at tillering stage. Considering the yield and salt injury at medium saline soil in southwestern reclaimed saline area, the application of basal fertilization before sowing was superior for improving seedling stand, and 14-20kg/10a fertilization rate was allowable.

A stable method for strain distinction using viral RNA 1 structures analyses was developed and compared with the combined RT-PCR and RAPD methods. Seven out of 61 random primers were found to be polymorphic based on RAPD analysis resulting on the differentiation of the 33 BaYMV isolates into four distinct groups according to geographical districts. The first and largest group includes 13 isolate and consists mainly of two-rowed malting barley in Haenam area. The second group had ten collections from inland in west southern. The third group had seven isolates from west southern coastal region, where mainly six-rowed naked barley is cultivated. The last fourth group included three isolates from Gyungnam region in east southern area. Conclusively, RNA 1 analysis proved to be stable and efficient method for strain distinction for Korean BaYMV isolates. Further, results of pathogenicity and RNA 1 structure analyses revealed four groups BaYMV strains and were distributed all over Korea, represented by Naju, Haenam-okcheon, Iksan and Milyang.

To investigate the application of biochemical markers' and small-sample methods using whole-wheat flours for screening in early generation in Korean wheat breeding system, 74 Korean wheats, including cultivars, local breeding lines and experimental lines, were analyzed. Seed storage protein and amylose contents of grains were evaluated. Biochemical makers, including granule bound starch synthase (GBSS), high molecular weigh glutenin subunits (HMW-GS) and friabilin were also evaluated by using one-dimensional sodium dodecyl sulfate-polyacryla-mide gel electrophoresis with a single kernel. The small­sample methods, including modified SDS-sedimentation test (MST), micro-alkaline water retention capacity (AWRC) and whole-wheat flour swelling volume (WSV) were also tested in this study. Protein content, MST and AWRC was 11.0 - 15.8~% , 2.7 - 26.2 ml and 71.9 - 109.7~% , respectively. Apparent and total amylose content and WSV was 20.6 - 25.0~% , 26.1 - 32.4~% and 9.0 - 16.9 ml, respectively. There were highly significant correlations between MST and AWRC (r=0.592, P<0.001), but Korean wheats showed no significant difference in protein content, amylose content and small-sample methods. In the biochemical markers, Korean wheats contained all three GBSS encoded by Wx loci, except for Suwon 252. Korean wheats showed the high frequency (58.1~% ) of 1Dx2.2 + 1Dy12 subunits of HMW-GS. Friabilin band was present in 46 lines (62.2~% ) and absent in 28 lines (37.8~% ). Friabilin-absence lines showed the higher MST (14.9 ml) and AWRC (92.1~% ) value than friabilin-presence lines (8.5 ml and 82.4~% , respectively).