• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.7 no.4
• /
• pp.257-266
• /
• 2002

To estimate the nitrogen budget and assess the purification function of a tidal flat ecosystem, a field survey was carried out at Hajeon tidal flat in Gomso Bay, the southern part of Byeonsan Peninsula, Chollabuk-do, Korea. A study area of 3.0$\times$4.5 ㎢ was established on the tidal flat and the concentrations of chlorophyll-a, DIN, DON, and TN were measured in the water column during the period of April 17-18, 1999: From the budget analysis, the loss rate of Chl-a was estimated to be -0.05 mg Chl/㎡/hr, which is approximately 7% of that at Issiki tidal flat in Aichi Prefecture, Japan. The lower loss rate of Chl-a in the study area was attributable to the lower standing crop of phytoplankton, the lower temperature that may reduce metabolic rates of biotic components and the lower biomass of macrobenthos in the study area. Over the 13.5 ㎢ of study area, Hajeon tidal flat removed 8.36$\times$10$\^$2/ kg N/day of TN, 5.36$\times$10$\^$3/ kg N/day of PON and 1.62$\times$10$\^$2/ kg N/day of phytoplankton-related PON, showing that the tidal flats may play an important role in removing nitrogen in coastal waters. The removal rate of PON, compared to the removal cost of the existing waste water treatment facilities, indicates that the economic value of the purification function of Hajeon tidal flat (13.5㎢) may be more than that of two large facilities.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.4
• /
• pp.632-640
• /
• 2017

In order to understand the seasonal and geographical characteristics of environmental factors and distribution of Escherichia coli by salinity gradient due to precipitation, we investigated abiotic and biotic factors during four seasons from February 2013 to November 2015. The study area was divided into three different zones based on salinity gradient and geo-oceanographic characteristics. During the study period, water temperature, salinity, Chlorophyll a, and secchi-depth varied in the range of $8.5-26.1^{\circ}C$, 13.5-34.4 psu, $0.4-74.0{\mu}g\;L^{-1}$, and 0.5-10.0 m, respectively. Salinity was low at Zone I, which was influenced by water flux from Tae-hwa River, especially in 2014. Salinity was gradually increased (one-way ANOVA; p < 0.05) toward Zone III located offshore of the bay. The highest colony form of E. coli was detected at Zone I. E. coli maintained a relatively low level at Zone III during all seasons. E. coli was correlated with transparency (r = -0.36; p < 0.05) and salinity (r = -0.53; p < 0.01), implying that those parameters might play important roles in the proliferation of E. coli. These results indicated that E. coli were strongly affected by frequent rain (< 50 mm) around inner stations in Ulsan Bay of Korea.

• Korean Journal of Breeding Science
• /
• v.41 no.4
• /
• pp.645-648
• /
• 2009

"Deuraechan" is a new japonica rice variety developed and registered by the rice breeding team of Department of Rice and Winter Cereal Crop, NICS, RDA in 2008. This variety was derived from a three way cross Iksan438, YR19105Acp222 and Milyang165. This variety has about 122 days of growth duration from transplanting to harvesting in Honam and Youngnam plain of Korea. It is about 76 cm in culm length and tolerance to lodging. In reaction to biotic stresses, it shows moderately resistance to blast, resistance to bacterial blight pathogen races from $K_1$ to $K_3$, and Rice stripe virus, but susceptible to other major diseases and insect pests. The milled rice of "Deuraechan" has high Quality, midium short grain. The milled rice yield of this variety is about 6.52 MT/ha in local adaptability test for three years. "Deuraechan" would be adaptable to Middle plain, Honam plain and Youngnam plain area of Korea.

• Korean Journal of Breeding Science
• /
• v.41 no.4
• /
• pp.564-567
• /
• 2009

"Boseog" is a new japonica rice cultivar developed from the three way cross of Kinuhikari//HR19621AC6/Sobibyeo and registered by the rice breeding team of Department of Rice and Winter Cereal Crop, NICS, RDA in 2008. This cultivar has about 110 days of growth duration from transplanting to harvesting in northern plain, northern and southern mid-mountainous area of Korea. This cultivar is about 72 cm in culm length and tolerant to lodging. In the reaction to biotic and abiotic stresses, it shows resistance to leaf blast, but susceptibility to bacterial blight, virus diseases and insect pests. The milled rice of "Boseog" exhibits translucent, relatively clear non-glutinous endosperm and midium short grain. It has similar amylose content(18.0%), lower protein content(6.3%), and similar palatability of cooked rice compared to Odaebyeo. The milled rice yield of this variety is about 5.03 MT/ha in local adaptability test. "Boseog" would be adaptable for ordinary transplanting in northern plain, mid-mountainous and southern mountainous area of Korea.

• Korean Journal of Breeding Science
• /
• v.40 no.3
• /
• pp.314-317
• /
• 2008

"Dami" is a new japonica rice variety developed and registered by the rice breeding team of Honam Agricultural Research Institute, NICS, RDA in 2006. This variety was derived from a cross between Iksan438 with lodging tolerance and high yield potential, and Iksan426 This variety has about 122 days of growth duration from transplanting to harvesting in Honam and Youngnam plain of Korea. It is about 83 cm in culm length and tolerance to lodging. In reaction to biotic stresses, it shows moderately resistance to blast, and resistance to bacterial blight pathogen races from $K_1$ to $K_3$, but susceptible to other major diseases and insect pests. The milled rice of "Dami" has high Quality, midium short grain. The milled rice yield of this variety is about 5.92 MT/ha in local adaptability test for three years. "Dami" would be adaptable to Middle plain, Honam plain and Youngnam plain area of Korea.

• Korean Journal of Breeding Science
• /
• v.43 no.1
• /
• pp.81-91
• /
• 2011

Rice wild relatives have been recognized as reservoirs of genetic reinforcements to improve cultivating rice against biotic and abiotic stresses. A wild relative, Oryza. minuta(BBCC; Acc. 101141), was hybridized with a Korean Japonica cultivar, 'Hwaseong'(AA), followed by ovule culture and several times of back crossings to overcome high level of sterility. During evaluation of the introgression lines, breeding line exhibited resistance to bacterial blight with reasonable agronomic performances, and nominated as an elite breeding line, the 'Suweon497'. A mapping population, to dissect genetic basis of the resistance, was constructed by using $F_2$ progenies of the 'Suweon497' ${\times}$ 'Milyang23'. Association analysis between SSR marker genotypes and pathogenisity levels of each $F_2$ progeny revealed the end terminal region of rice chromosome 11 as the nesting place for the wild rice derived bacterial blight resistance gene, where at least four other genes, Xa3, Xa4, Xa26 and Xa31, have been reported.

• The Korean Journal of Mycology
• /
• v.46 no.4
• /
• pp.479-490
• /
• 2018

Red pepper is seriously damaged by thrips (Thrips palmi) and anthracnose caused by Colletotrichum acutatum throughout its development. Because of biotic constraints, producers often depend on chemicals that are expensive and have adverse effects on the environment, operator, and beneficial insects. In addition, resistance is developed because of the repeated use of chemicals. In recent decades, the use of microorganisms in crop protection has become a credible alternative because it is eco-friendly. In this study, we aimed to select isolates with insecticidal and fungicidal activities against the pathogens that cause anthracnose and thrips. We treated T. palmi adults and juveniles with 13 strains of entomopathogenic fungi (isolated from the soil by using the insect-bait method), and 6 strains showed excellent insecticidal activity (70-100%) 5 days after the treatment. The selected isolates were cultured with C. acutatum to screen for the strain with excellent anti-fungal activities, among which an isolate FT333 showed more than 95% control efficacy against C. acutatum in vitro. The isolate was identified as Isaria javanica through its morphological characteristics and phylogenetic analysis of the ITS and ${\beta}-tubulin$ nucleotide sequences. The Isaria javanica FT333 isolate could be used effectively for dual bio-control of thrips and anthracnose during red pepper cultivation.

• Journal of Ecology and Environment
• /
• v.43 no.1
• /
• pp.43-60
• /
• 2019

Background: Tropical montane forests played an important role in the provision of ecosystem services. The intense degradation and deforestation for the need of agricultural land expansion result in a significant decline of forest cover. However, the expansion of agricultural land did not completely destruct natural forests. There remain forests inaccessible for agricultural and grazing purpose. Studies on these forests remained scant, motivating to investigate biomass and soil carbon stocks. Data of biomass and soils were collected in 80 quadrats ($400m^2$) systematically in 5 forests. Biomass and disturbance gradients were determined using allometric equation and disturbance index, respectively. The regression modeling is employed to explore the spatial distribution of carbon stock along disturbance and environmental gradients. Correlation analysis is also employed to identify the relation between site factors and carbon stocks. Results: The result revealed that a total of 1655 individuals with a diameter of ${\geq}5cm$, representing 38 species, were measured in 5 forests. The mean aboveground biomass carbon stocks (AGB CS) and soil organic carbon (SOC) stocks at 5 forests were $191.6{\pm}19.7$ and $149.32{\pm}6.8Mg\;C\;ha^{-1}$, respectively. The AGB CS exhibited significant (P < 0.05) positive correlation with SOC and total nitrogen (TN) stocks, reflecting that biomass seems to be a general predictor of SOCs. AGB CS between highly and least-disturbed forests was significantly different (P < 0.05). This disturbance level equates to a decrease in AGB CS of 36.8% in the highly disturbed compared with the least-disturbed forest. In all forests, dominant species sequestrated more than 58% of carbon. The AGB CS in response to elevation and disturbance index and SOC stocks in response to soil pH attained unimodal pattern. The stand structures, such as canopy cover and basal area, had significant positive relation with AGB CS. Conclusions: Study results confirmed that carbon stocks of studied forests were comparable to carbon stocks of protected forests. The biotic, edaphic, topographic, and disturbance factors played a significant variation in carbon stocks of forests. Further study should be conducted to quantify carbon stocks of herbaceous, litter, and soil microbes to account the role of the whole forest ecosystem.

• Journal of Wetlands Research
• /
• v.20 no.4
• /
• pp.322-329
• /
• 2018

In this study the community characteristics of benthic macroinvertebrates distributed in stream of Gaya Mountain were figured out and the correlation with the physicochemical water quality factors were calculated. During the study period, total 4 phyla, 6 classes, 13 orders, 36 families, 100 species of benthic macroinvertebrates were recorded. Ephemeroptera were the most dominant followed by Trichoptera, Plecoptera, Diptera, Non-insecta, Hemiptera, and Odonata. The overall dominant species was Cincticostella levanidovae by dominance rate in 17.72%, subdominant species was Hydatophylax nigrovittatus by dominance rate in 6.15%. The biotic indices showed the diversity index 5.17, richness index 12.44, dominant index 0.24 and evenness index 0.78, there is no absolutely dominant benthic macroinvertebrates in the stream of Gaya Mountain. We identified the correlation between the species number and individuals of main taxa and the physicochemical water quality factors. Ephemeroptera and Plecoptera showed a negative correlation with water temperature, but they represented a positive correlation with the dissolved oxygen. This results suggest that water temperature and dissolved oxygen are important physicochemical water quality factors affects the distribution of Ephemeroptera and Plecoptera, the indicators of clean water stream.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.21 no.2
• /
• pp.111-116
• /
• 2019

The biotic stress of garlic and tobacco infected by bacteria and virus was evaluated using a thermal imaging camera in a growth chamber. The remote sensing technique using the thermal camera detected that garlic leaf temperature increased when the leaves were infected by bacterial soft rot of garlic. Furthermore, the temperature of leaf was relatively high for the leaves where the colony-forming unit per mL was large. Such temperature patterns were detected for tobacco leaves infected by Cucumber Mosaic Virus using thermal images. In addition, the crop water stress index (CWSI) calculated from leaf temperature also increased for the leaves infected by the virus. The event such that CWSI increased by the infection of the virus occurred before visual disease symptom appeared. Our results suggest that the thermal imaging camera would be useful for the development of crop remote sensing technique, which can be applied to a smart farm.