• Korean Journal of Weed Science
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• v.30 no.3
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• pp.206-214
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• 2010

The laboratory and green house studies evaluated the effect of three different environmental factors on the seed germination, seedling emergence and survival of four major weed species in coconut plantations, Mimosa pudica, Ureana lobata, Panicum maximum and Pennisetum polystachyon. Germination percentage of all the weed species was significantly reduced with increasing soil moisture stress, no germination was observed at -0.9 MPa. Germination of both grass seeds ranged from 8% to 25% and 10% to 45% as moisture stress decreased from -0.4 MPa to 0 MPa, respectively. In contrast, seeds of M. pudica, and U. lobata were moderately tolerant to soil moisture stress and best adapted to moist environment. All the weed species seeds germinated over a wide range of soil pH values with the highest germination occurring at pH 6. In all the species, seedling emergence was declined rapidly with increasing depth with the exception of U. lobata. Seedling emergence significantly declined when the duration of flooding was three days or longer in dicotyledonous weed species and two days or longer in monocotyledonous weeds. This study illustrates the adaptability of these weeds to different environmental conditions which would enable the development of management strategies to reduce their populations below economic threshold levels in coconut plantations.

• Korean Journal Plant Pathology
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• v.14 no.6
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• pp.606-611
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• 1998

An antagonistic bacterium, Pseudomonas flurorescens MC07 inhibited the mycelial growth of Rhizoctonia solani, Pythium ultimum, Fusarium oxysporum, and Phytophthora capsici in on potato dextrose agan (PDA) and other media. The strain MC07 conlonizes various plant roots and possesses antifungal activity. To determine the role of antifungal activity of the bacterium in disease suppression, a mutant Okm3-4 which lost its activity was isolated after screening 2,500 colonies generated by Omegon-Km insertions. The mutant Okm3-4 showed diminished growth inhibition of R. solani, P. ultimum, F. oxysporum, and Ph. capsici in vitro and had reduced suppressive effects on sesame damping.-off compared to the parental strain. In soils, accumulation of the pathogens by continuous cropping, 90% of sesame plants were killed by natural infection of damping-off whereas, only 29% of plants grown from seeds treated with MC07 were killed. On the other hand, 85% of plants died when sesame seeds were treated with the Okm3-4 cells. This indicated that antifungal activity of MC07 in vitro is directly responsible for the suppression of damping-off disease. Emergence rates of sesame seeds in pots containing diseased soil were 33%. However, MC07 treatments on seeds significantly improved emergence rates, which has similar effects of Benomyl treatment. The mutant Okm3-4 exhibited 53% of emergence rate. This indicated that antifungal activity of MC07 also affects the emergence rate of sesame seeds.

• International Journal of Industrial Entomology and Biomaterials
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• v.21 no.2
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• pp.189-191
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• 2010

The black soldier fly, Hermetia illucens, has a worldwide distribution in the tropics and warm temperate regions and is active in the Korea from May through October. This species colonize a wide variety of decomposing vegetable and animal matter and oviposits in a variety of decomposing materials. In this study, how the black soldier fly pupation, adult emergence and mating rate changed with season at the artificial rearing system was investigated. The black soldier fly larvae and pupae were reared under laboratory condition ($27^{\circ}C$, 60% R.H.). In this study, under the laboratory condition, pupation and adult emergence were not influenced by season, but the data shows definitely different mating numbers throughout whole year. The time of the day is changed with seasons and it influence to mating on artificial rearing. To culture the black soldier fly throughout the year in Korea needs a more deep study under the artificial rearing system.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.1
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• pp.50-55
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• 2003

Herbicidal activity of $\delta$-aminolevulinic acid(ALA), an intermediate for the biosynthesis of tetrapyrroles such as chlorophyll, heme, bacteriochlorophyll, and vitamin $\textrm{B}_{12}$ analogues, was examined to determine the variation in phytotoxic potential against different plant species as affected by different application methods. Seed-soaking treatment, ALA at low concentrations did not affect shoot and root lengths of test plants while at highest concentration reduced them by 20 to 30%. Alfalfa showed the most tolerant response to ALA in both pre- and post-emergence application, and followed by rice. When applied with pre-emergence, cotyledons of Chinese cabbage were severely bleached with 0.5 mM of ALA at 24 hrs after application, and root growth of rice, barnyard grass, and alfalfa was significantly inhibited with increasing of concentration. With post-emergence application, ALA at 2 to 4 mM reduced shoot and root growths of Chinese cabbage and barnyard grass completely. Herbicidal effects of ALA were more enhanced in the treatment combined with 2,2-dipyridyl sthan single application in barnyard grass and Chinese cabbage. The results suggest that alfalfa was the most tolerant to ALA among the tested plants, and that post-emergence application of ALA exhibited greatest photodynamic activity against tested plants.

• Korean Journal of Plant Resources
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• v.19 no.6
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• pp.687-691
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• 2006

This experiment was conducted on rice (cv. 2005 Thaoi) seeds to study whether priming with deep sea water (DSW) results in enhancement of seed emergence and seedling growth and to identify the optimum concentration of Deep Sea Water (DSW) for priming. Two experiments were conducted subsequently. In experiment 1, four concentrations of the DSW (10%, 20%, 30% and 40%), and in experiment 2, five concentrations of DSW (10%, 15%, 20%, 25% and 30%) were prepared and seeds were primed for 24 hours duration at $25^{\circ}C$. Beside this, hydro priming with plain water was also included as a control. Experiments were laid out in Completely Randomized Design (CRD) with three replications. Result showed that 20% DSW seed priming treatment had improved the emergence, seedling height, number of roots and root length as compare to other with DSW or without DSW treatments. Beyond 20% DSW priming (i.e. 25%, 30% and 40%) were not suitable for priming the seed. On the basis of seedlings growth parameters; emergence, seedling height, root number and length, and shoot root ratio, 20% DSW priming was the best priming treatment.

• Journal of Ginseng Research
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• v.37 no.2
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• pp.254-260
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• 2013

Greenhouse and field experiments with American ginseng (Panax quinquefolius L.) stratified seed sown at depths of 10 to 100 mm were carried out to determine effects of seeding depth on seedling emergence, growth and development and to calculate optimum seeding depth. The time to 50% seedling emergence ($E_{50}$) in the field increased linearly from 17 d at 20 mm seeding depth to 42.5 d at 80 mm. Seedling emergence and root weight (economic yield) at the end of the first year each increased quadratically with the increase of seeding depth. Maximum emergence and root yields were produced at sowing depths of 26.9 and 30.6 mm respectively. In a greenhouse pot experiment, increasing seeding depth from 10 to 100 mm increased partitioning of dry matter to leaves from 23.6% to 26.1%, to stems from 6.9% to 14.2%, and decreased dry matter to roots from 69.5% to 59.7%. Optimum seeding depth was 31.1 mm for a corresponding maximum root weight of 119.9 mg. A predictor equation [X (seeding depth, mm)=Y (seed weight, mg)/9.1+20.96] for seeding depth for ginseng, based on data for ten vegetable crops, their seed weights and suggested seeding depths, predicted a seeding depth of 28.3 mm for ginseng similar to that reported above for most pot and field experiments.

• Mycobiology
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• v.46 no.4
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• pp.361-369
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• 2018

The rice blast fungus, Magnaporthe oryzae, is an important pathogen of rice plants. It is well known that genes encoded in the genome have different evolutionary histories that are related to their functions. Phylostratigraphy is a method that correlates the evolutionary origin of genes with evolutionary transitions. Here we applied phylostratigraphy to partition total gene content of M. oryzae into distinct classes (phylostrata), which we designated PS1 to PS7, based on estimation of their emergence time. Genes in individual phylostrata did not show significant biases in their global distribution among seven chromosomes, but at the local level, clustering of genes belonging to the same phylostratum was observed. Our phylostrata-wide analysis of genes revealed that genes in the same phylostratum tend to be similar in many physical and functional characteristics such as gene length and structure, GC contents, codon adaptation index, and level of transcription, which correlates with biological functions in evolutionary context. We also found that a significant proportion of genes in the genome are orphans, for which no orthologs can be detected in the database. Among them, we narrowed down to seven orphan genes having transcriptional and translational evidences, and showed that one of them is implicated in asexual reproduction and virulence, suggesting ongoing evolution in this fungus through lineage-specific genes. Our results provide genomic basis for linking functions of pathogenicity factors and gene emergence time.

• Korean Journal of Environmental Biology
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• v.39 no.4
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• pp.536-541
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• 2021

Pantala flavescens is a dominant Odonata species in the rice fields in Korea. To determine the effects of different temperatures on its larval growth and emergence, field and laboratory experiments were conducted. Larval growth was also monitored in mono-cropping and double-cropping rice fields. The growth of larvae was monitored every week by measuring the head width. In the field experiment, no difference was found in larval growth and emergence between the control temperature and +1.9℃ of the control temperature. The larval growth was greater at 23℃ than at 20℃ laboratory temperatures, and no emergence was recorded at either temperature after eight weeks of monitoring. There was a quadratic relationship between larval growth and temperature in an incubator at five temperature regimes of 15, 20, 25, 30, and 35℃. Midseason water drainage caused the extinction of the existing individuals and newly hatched larvae dominated after re-watering in the rice fields. Larval size was greater in double-cropping fields than in mono-cropping fields in late July but the tendency was reversed in early August. The results of this study suggest that temperature warming will directly promote the larval growth of P. flavescens and indirectly influence seasonal growth via changes in water management in rice fields.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.6
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• pp.460-464
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• 2003

White spunbonded fabrics has been utilized toy covering in rice seedling nursery. This study, therefore, was carried out to examine the effect of light quality on seedling emergence, growth, morphology, chlorophyll content and photosynthesis to get the information on the color of the fabrics. Blue, red and far-red lights were treated immediately after sowing seeds of three cultivars, Dongjinbyeo, Ilmibyeo and Daesanbyeo. Seedling emergence, growth and morphology, chlorophyll content and photosynthetic rate were measured. Seedling emergence rate of Dongjinbyeo and Daesanbyeo was low under far-red light treatment compared to those under blue and red light ones. Although the rate of Ilmibyeo was not different from three light treatments. Far-red light treatment showed similar response in plant height and leaf length, but yee light increased number of roots. Shoot and root dry weight was the highest in blue and red light treatments, respectively. Total dry weight, however, was the lowest under far-red light treatment. While chlorophyll content and photosynthetic rate of the three cultivars did not showed consistent response, those were the greatest under red light treatment, and were decreased in order of blue and far-red light treatment.

• International Journal of Industrial Entomology and Biomaterials
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• v.31 no.2
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• pp.103-106
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• 2015

The oriental tobacco budworm, Helicoverpa assulta (Lepidoptera: Noctuidae), is classified as a quarantine pest that must be controlled for the exportation of Korean paprika to the USA. We performed a confirmatory test of gamma irradiation against the last-instar larvae and pupae of H. assulta in paprika. Previous, small-scale gamma irradiation at a dose of 100 Gy to the last-instar larvae allowed emergence of adults, though they were abnormal, but 200 Gy prevented adult emergence completely. For pupae, irradiation of 5- to 6-day-old pupae with 300 Gy prevented normal emergence completely. To gather confirmatory data applicable to phytosanitary quarantine regulations, larvae and pupae were placed inside paprika in a box and were irradiated with 200 Gy and 300 Gy, respectively. After irradiation with 200 Gy (measured doses 170-199 Gy) of 2,186 individuals of the last-instar larvae, 10.84% survived, but either formed abnormal pupae (7.57%) or died during the pupal stage (3.27%), resulting in no emergence of normal adults. For pupae, the dose of 300 Gy (measured doses 276-319 Gy) given to 1,200 pupae allowed 10.75% to survive and 9.17% to emerge with deformity. However, 1.58% of irradiated pupae emerged normally, requiring an increased dose for complete prevention of normal emergence. Subsequently, an increased dose of 400 Gy (measured doses 340-402 Gy) to 1,005 pupae allowed 88.35% to emerge, but all emerged with deformity. Thus, irradiation treatment with a minimum dose of 400 Gy will provide quarantine security for all premature H. assulta in exported paprika.