Barley Yellow Mosaic Virus (BaYMV) caused significant reduction in barley yield and is difficult to control due to alive parasitic soil-borne fungus, Palmyra gamines that transmits the, virus. Previous studies have indicated that a virus-free soil could be infested by using virus-contaminated farming machineneries and implements. For the further confirmation of this finding, different proportions of BaYMV-infested soil were mixed into virus free soil. Three barley varieties (Hordum vulgarae, cv "Olbori", "Baegdong" and "Sacheon 6") were sown in pots treated with different rate of P. graminis-infested soil ranging from 0% to 100% in October 20, 2001. Results showed that BaYMV infection increased as the rate of infested soil increased. Initial symptoms were observed in a pots treated with 10% infested soil in all the 3 varieties of barley. "Olbori" had about 5% infection in 20% infested soil and about 10% infection in 40% or 50% infested soil and about 20% infection in 60% infested soil. In "Baegdong", the trend of BYMV occurrence was similar with "Olbori" but the time of severe infection was earlier than "Olbori". BaYMV infection in "Sacheon 6" was even earlier than "Baegdong" with much more severe symptoms than "Baegdong". The growth rate of barley was affected by about 19-22% when grown in 20% infested soil. As the rate of BaYMV infested soil increased the heading date was delayed but the maturing date was early in "Olbori" and "Sacheon 6". Also, reduction rate of culm length in 3 varieties increased with increase of infested soil content. However, "Olbori" showed the highest reduction. "Sacheon 6", have been characterized with long spike length, however was significantly reduced as the infested soil increased. On the other hand, spike length of "Olbori" was not significantly affected despite of increased of infested soil. The reduction rate of 1000 kernel weight was higher in large kernel size cultivar "Sacheon 6" and "Olbori" than small kernel size "Baegdong" as increase of BaYMV-infested soil content.

The adverse effects of salinity and drought on soybean cultivar Hwangkeumkong were also investigated. Endogenous bioactive gibberellins GA1 and GA4, jasmonic acid (JA), abscisic acid (ABA) and salicylic acid (SA) content and pertinent changes in response to basic and double NaCl (70 mM & 140 mM) and PEG (8% & 16%) were examined. We found that plant growth and yield components significantly reduced with the application of NaCl and PEG during pre-flowering and post-flowering growth periods. The endogenous bioactive GA1 and GA4content decreased under elevated salt and drought stress. However, an insignificant increase in GA4level was noted with 8% PEG, applied during post-flowering growth stage. JA levels significantly increased with NaCl and PEG applications, but declined with elevated PEG applied during post-flowering period. SA level drastically reduced with NaCl, while insignificantly reduced with PEG. Endogenous ABA contents of leaves increased with elevated NaCl and PEG application. The endogenous bioactive GA1 and GA4, JA and ABA content of soybean leaves were analyzed through chromatograph/ mass spectrometer (GC/MS) in selected ion monitoring (SIM) mode, while SAcontent was quantified with HPLC.

The removal of nitrogen compounds from a wastewater is essential and it is often accomplished by biological process. An aerobic nitrate-removing bacterium was isolated from a municipal sewage treatment plant and soil. On the basis of its morphological, cultural and physiological characteristics and 16S rRNA sequencing data, this strain was identified as Pseudomonas fluorescens, and named as P. fluorescens K4. The optimal conditions of the initial pH and temperature of media for its growth were 7.0~8.0 and 30℃, respectively. P. fluorescens K4 was able to remove 99.9% of nitrate after 24 h in a culture. The strain could grow with a nitrate concentration up to 800 mg/l and was able to remove 99.9% of nitrate after 104 h of incubation. The optimal electron donor was sodium citrate for a nitrate removal. The strain K4 showed a capability of a complete nitrate removal when the initial C/N ratio was 1.0. An effect of the initial seed concentration was observed for a cell of 10% (v/v) for a nitrate removal. Especially P. fluorescens K4 could completely remove 200 mg/l ammonium for 3 days.

Hardy Kiwifruit (A. arguta (Sieb. & Zucc.) Planch. ex Miq.) is one of the valuable species due to their edible fruits, high content of nutritious substances, especially abundant of vitamin C, and distinctive flavor and medicinal usage. Therefore, we have developed a new cultivar of A. arguta with large fruits and high yielding. For this, 168 candidate plants were collected from wild populations in 12 locations from 4 provinces (Chungbuk, Gangwon, Gyeongnam, and Jeonbuk) from 1985 to 1987. A clone bank that contained highly productive, superior genotypes of A. arguta was assembled in 1988, and 32 excellent clones were selected in 1996 through the clone tests for growth and fruiting. From these clones, we have been regularly investigated yield trials for the fruiting characteristics to evaluation of major agronomic traits, which are the average of Fruit Length (FL), Fruit Width (FW), Weight of Fruit (WF) and Individual Yield (IY), during consecutive 6 years (1997~2002). Finally, we have selected the new A. arguta cultivar, “Dae-Sung” with large fruits and high yielding and registered as a new variety denomination and certificated for variety production and merchandising in 2006 (Table 1). This cultivar is characterized by a diploid plant and oblong type in the fruit shape, and is particularly characterized by large fruit size (Fig. 1, Table 3). The major agronomic traits of this cultivar showed the large selection effect with an average of 41.6 mm (FL), 29.9 mm (FW), 18.9 g (WF), and 25.9 kg (IY), which are 28.8%, -0.7%, 16.7%, and 232.0% compared to the mean of 29 sample trees, respectively (Table 2).