• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.65 no.4
• /
• pp.406-415
• /
• 2020

Maize (Zea mays L.) is one of the most valuable agricultural crops and is grown under a wide spectrum of environmental conditions. However, maize is moderately sensitive to salt stress, and soil salinity is a serious threat to its production worldwide. In this study, we used ethyl methane sulfonate (EMS) to generate salt-tolerant silage maize mutants. We screened salt-tolerant lines from 203 M₃ mutant populations by evaluating the morphological phenotype after salt stress treatment and selected the 140ES91 line. The 140ES91 mutant showed improved plant growth as well as higher proline content and leaf photosynthetic capacity compared with those of wild-type plants under salt stress conditions. Using whole-genome re-sequencing analysis, 1,103 single nucleotide polymorphisms and 71 insertions or deletions were identified as common variants between KS140 and 140ES91 in comparison with the reference genome B73. Furthermore, the expression patterns of three genes, which are involved in salt stress responses, were increased in the 140ES91 mutant under salt stress. Taken together, the mutant line identified in our study could be used as an improved breeding material for transferring salt tolerance traits in maize varieties.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.30 no.2
• /
• pp.190-194
• /
• 1985

Three different improved pre-release rice varieties, when transplanted at different ages of seedlings, showed that 40 day old seedlings produced the longest panicle, whereas 30 day old seedlings produced the highest culm length among treatments in all treated varieties. 40 day or older seedlings reduced the culm length remarkably mainly due to decrease in lower internodes in IET7251 and BG400-1, and due to upper as well as lower internodes in B44b-50-2-2-5-1. 30 day old seedlings produced maximum number of visible internodes. Heading as weil as maturity was delayed with increasing age of seedling.

• ALGAE
• /
• v.22 no.1
• /
• pp.1-10
• /
• 2007

To gain insights into the phylogenetic relationships of genus Staurastrum and Staurodesmus, we analyzed nuclearencoded small subunit rDNA of 82 strains, and chloroplast atpB gene sequences of 44 strains belonging to three genera (Staurastrum, Staurodesmus, Cosmarium). Excluding the Staurastrum muticum and S. orbiculare, forty five strains of genus Staurastrum formed a well supported clade. It was shown that with no cell wall sculpture and processes, these two species have a strong phylogenetic relationship with genus Staurodesmus. Therefore, it is strongly recommended to transfer Staurastrum without processes and cell wall sculpture into Staurodesmus. S. obsoletus is a taxa that is transferred from Cosmarium. But, from this study, it has shown a phylogenetic relationship with Cosmarium. Therefore, this species is strongly recommended to transfer back to Cosmarium instead of Staurodesmus. As it was studied before, genus Staurastrum has shown monophyletic. Since the genus taurodesmus groups with Cosmarium, they were shown to be polyphyletic.

• Parasites, Hosts and Diseases
• /
• v.30 no.4
• /
• pp.283-288
• /
• 1992

To observe the transmission patterns of karyotype of Pneumocystis carinii (Pc) by rat colonies, three strains of rats, Sprague-Dawlcy(SD), Wistar(W) and Fisher (F) from various animal vendors, were suppressed of their immunity by injection of methyl prednisolone. They were kept for 5 to 13 weeks in 3 different animal rooms, A, B, and C. The purified organisms were prepared in low melting point agarose gel by embedded Iysis method for pulsed field gel electrophoresis. Field inversion gel electrophoresis showed 2 patterns of the kart·otype of Pc. The rooms A and C contained SD rats from the source p, and also the room A was used for F and W rats. However, Pc from all of the SD and F rats in the room A showed same karyotypes, the pattern I. The SD rats from difFerent vendors, M and 5, were reared in the room B, and shared the same Pc karyotypes, the pattern II . The rats of W strain were from the vendor M, and immune-suppressed in the animal room A. Five weeks after the expe- riment, the Pc showed the karyotype pattern II but the pattern became mixed with the type I after 7 to 8 weeks. The Bindings revealed that the animals born and reared in the same animal quarter harbored Pc with same karyotypes. If the animals were kept under immune-suppression in the same room with heavily infected hosts, they could be infected by Pc from their neighbors. The present experimental findings suggest that Pc is transmitted among rats through the air.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.39 no.2
• /
• pp.180-186
• /
• 1994

Lipoxygenase activity of soybean seeds of approximately 507 genotypes as well as its inheritance and selection efficiency in early breeding generation was measured in the Department of Agronomy, Seoul National University to facilitate breeding for low lipoxygenase activity of soybean. Average seed lipoxygenase activity of 507 cultivars and strains was 350 unit (unit: $\Delta$0.01 /min. /mg at 234nm) and ranged from 50 to 670 unit. There was no difference in mean lipoxygenase activity according to apparent seed characters such as seed coat and embryo color. But early mature soybean genotypes had fairly low lipoxygenase activity. Lipoxygenase activity was inherited quantitatively, in which additive effect was greater than dominant one and proportion of gene with positive effects was similar to that with negative ones. Estimated narrow- and broad-sense heritabilities were 0.78 and 0.86 for lipoxygenase activity, respectively. Heritability measured from selection in early breeding lines for high or low lipoxygenase activity was 64~76% or 54~62%, respectively. And selection for high lipoxygenase activity increased by 29.7~44.7%, whereas that for low ones decreased by 21.8~27.3%, respectively, when compared to random population. Clear effect in selecting of lipoxygenase activity was present in early generation.

• Korean journal of applied entomology
• /
• v.12 no.2
• /
• pp.83-87
• /
• 1973

Experiment was conducted to study resistance of rice varieties and lines originated from Korea and IRRI sources to the zigzag-striped leafhopper, Recilia (Inazuma) dorsalis MOTSCHULSKY The nature of varietal resistance to the insect was evaluated from the viewpoints of feeding and ovipositional preferences and antibiosis. The varieties Su-Yai-20, Muthumanikam, PTB-18 and Vellanlangalayan were resistant and DV-139 moderately resistant to tile zigzag-striped leafhopper, and the other varieties tested were susceptible. Feeding and ovipositional preferences were significantly different among the varieties, but no correlation was observed between the two preferences. The nature of resistance of rice to the insect seemed to be related with The non-feeding preference, not non-ovipositional preference. The resistant (Vellanlangalyan and Su-Yai 20) and moderately resistant(DV-139) varieties had high antibiosis against the zigzag-striped leafhopper.

• Research in Plant Disease
• /
• v.17 no.2
• /
• pp.211-215
• /
• 2011

Cucumber mosaic virus (CMV)-like isolate was collected from Raphanus sativus (cv. Choon-hyang), which showed mosaic symptoms. The isolate was confirmed to a strain of CMV by host responses in Vigna unguiculata, Chenopodium amaranticolor and Gomphrena globosa, by viral genome composition with RT-PCR and PCR-RFLP, and by serological analysis. Symptom developed by the strain of CMV was severe in Nicotiana benthamiana, N. glutinosa, N. tabacum (cv. Samsun, cv. Xanthi), Cucumis melo (cv. Early hanover), Cucumis sativus (cv. White wonder), Capsicum annuum (cv. Chung-yang and cv. Geum-top), but mild symptom was developed in Raphanus sativus (cv. Choon-hyang), Brassica rapa ssp. pekinensis (cv. Bul-Am No. 3), and B. juncea (cv. Daenong Jukgot). Newly isolated strain of CMV could infect diverse crops including Solanaceae, Cucurbitaceae and Brassicaceae. We designated the new strain of CMV as Gn-CMV based on the novel infectivity of Brassicaceae. In double-stranded (ds) RNA analysis, Gn-CMV consisted of 3.3, 3.0, and 2.2 kb genomes likewise other strains of CMV. SDS-polyacrylamide gel electrophoresis (SDS-PAGE) showed 28 kDa of the CMV coat protein. By restriction enzyme mapping using Cac8I, ClaI and MspI of RT-PCR products indicated that Gn-CMV belongs to CMV subgroup I.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.24 no.11
• /
• pp.1506-1512
• /
• 2000

Control of shock may be important in the hydraulic system and necessary to avoid failure and to improve the efficiency of operation. This study addresses the design and use of an orifice to provide the desired control of the hydraulic actuator system. The experimental apparatus is an idealization of an automobile shift system. Control is accomplished by installing three different types of orifices at appropriate locations in the system. Experimental results show that the orifice can be used to obtain the control of shock and control level depends on the orifice size, orifice type, operating pressure and flow rate.

• Proceedings of the KIEE Conference
• /
• 2009.07a
• /
• pp.266_267
• /
• 2009

22.9kV HTS(High Temperature Superconducting) cable and SFCL(Superconducting Fault Current Limiter) will be installed to Icheon 154kV substation for real distribution power system operation in 2010. This paper proposes CLR (Current Limiting Resistance) specification of the SFCL and fault current condition fo the HTS cable for applying to Korean power system.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.33 no.4
• /
• pp.272-277
• /
• 2009

The liquid phase LPG injection (LPLi) system (the 3rd generation technology) has been considered as one of the most promising fuel supply systems for LPG vehicles. To investigate the reaction characteristics of LPG with rubber parts in LPLi system, various rubbers were tested. The results showed that the amount of residue from the cover rubber of a fuel pump was increased about 10 times after testing. Furthermore, the amount of sulfur and nitrogen species which are considered as main sources of deposit formation in LPLi fuel injectors were also found to be higher than those in original LPG fuel. In addition, these residues made the core parts of LPLi injector such as needle and nozzle, partially worn, which eventually causes leakage in LPLi injectors.