• Korean Journal of Weed Science
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• v.17 no.4
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• pp.390-399
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• 1997

This experiment was conducted to introduce PAT (phosphinothricin acetyltransferase, non-selective herbicide bialaphos resistant gene) gene into potato (Solanum tuberosum. cv. Desiree). Optimal shoot regeneration from leaf discs and stem segments was obtained in MS medium supplemented with 0.1 mg/L IBA and 0.5 mg/L BA, and the frequency of shoot regeneration was 54% in left discs and 46% in stem segments. In this condition, leaf discs and stem segments of potato were co-cultivated with A. tumefaciens MP90 which contained binary vector with GUS: :NPTII gene and PAT gene. Transgenic shoots were regenerated from leaf and stem-derived calli on selection medium with 100mg/L kanamycin. The 100${\mu}M$ acetosyringone treatment during the co-cultivation highly enhanced(4 times than the control) the shoot regeneration on selection medium. When the putative transgenic plants were transferred to medium with 10mg/L basta, all of them were survived. After PCR. GUS test, and Southern blot analysis of the survived plant, we confirmed that the gene was stably integrated into the potato genome and expressed. After the transgenic plants were transplanted in soil, and the transgenic plants were sprayed with the herbicide basta (300ml/10a), the transgenic plants remained green but control plants were died.

• Korean Journal of Weed Science
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• v.15 no.3
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• pp.175-182
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• 1995

The experiment was conducted to obtain basic information on weed ecology and effective weed control in direct-seeded rice Gelds at National Yeongnam Agricultural Experiment Station in 1994. Double cropping system of rice-barley reduced weed occurrence about 30% as compared with rice single cropping due to allelopathic effect of barley residue or stubble. Occurrences of red rice (weedy rice), barnyard grass and water foxtail were closely related with tillage method; the greatest occurred in no tillage plot followed by rotavation only and plow plus rotavation. Period of seed germination of barnyard grass and carbgrass varied with temperature and soil depth. In the same environmental condition, the germination period of barnyard grass shortened 3 to 5 days as compared with that of carbgrass. Two systematic applications of herbicides, that is, the first application at 10 to 15 days after seeding and the second at just after flooding, were the most recommendable system in dry-seeded rice field in terms of weed suppression and yield capacity.

• Weed & Turfgrass Science
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• v.4 no.4
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• pp.279-287
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• 2015

The present research was carried out in order to investigate the occurrence of problematic weed species in Cnidium officinale Makino. Field in South Korea. Total 53 sites of the 3 different regions in S. Korea were investigated from May to October, 2014. In Cnidium officinale fields, the identified weeds were distributed in 35 families and 99 species. Total 5 communities that consist of Commelina communis, Eleocharis kuroguwai, Persicaria vulgaris, Chenopodium album-Acalypha australis, and Galinsoga ciliata dominated the appearance. The weeds occurred in Cnidium officinale fields were divided into three groups in principal component plot analysis (PCA). It was observed that in control weeds plots; 20 plants of Cnidium officinale fresh weight is 739.9 g while the uncontrolled plots have no Cnidium officinale plants. The current investigation could be useful for estimation of future weeds occurrence, weed flora dynamics and establishment of weed control methods in Cnidium officinale fields in Korea.

• Korean Journal of Weed Science
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• v.30 no.2
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• pp.164-170
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• 2010

In organic agriculture, cover crops are used for weed control. Cover crops inhibited weed germination or growth by allelopathy or shading effects. In this study, we used rye as cover crop to control weed in organic soybean field. The main treatment was rye using method such as living mulch, incorporating and mowing. Sub-treatment was rye planting density and soybean planting density. One month after soybean sowing, weed emergency and growth had been highly suppressed by rye in all treatments. Living mulch treatment was the best effective way to control the weed about 92%, and mowing treatment was the second about 75% compare to control. The weed control efficiency between rye planting densities was similar during one month. Soybean planting density treatment was same result as rye planting density. As a result of this experiment, we recommend rye as living mulch in one row planting.

• Korean Journal of Weed Science
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• v.30 no.2
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• pp.143-152
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• 2010

Herbicidal characterisitcs of natural product chrysophanic acid were investigated in a greenhouse condition. At early- and middle-stage post-emergence treatments, several grasses and broadleaf weeds appeared to be very susceptible to chrysophanic acid. However, any significant herbicidal activity treated by pre-emergence did not occur at concentration ranges from 31.3 to 1,000 ug $mL^{-1}$. Herbicidal activity of chrysophanic acid estimated by visual injury for large crabgrass was much higher when applied at 7 to 14 days after seeding than at 21 and 28 days after seeding. By post-emergence treatment, chrysophanic acid caused very considerable phytotoxicity on several grasses and broadleaf crops. In herbicidal interaction experiments determined by Colby's method, the effect of chrysophanic acid and caryophyllene oxide tank-mixture showed very high synergistic activity. Although chrysophanic acid did not give any pre-emergence effect, herbicidal spectrum tended to be very wide and strong when treated by post-emergence. These results suggest that chrysophanic acid possesses a possible potential to develop as a natural herbicide.

• Korean Journal of Weed Science
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• v.30 no.2
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• pp.177-182
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• 2010

This environment-friendly study was conducted to investigate the effects of winter barley as cover crop on the suppression of weeds and on the growth of dry direct seeded rice. The present study clarified the effects of winter barley as a cover crop on the weed vegetation, expressed as a multiplied ratio. In cultivation quality of rice, seedling stand was ranged from 104~112 $m^{-2}$. And, seeding stand of barley was the highest seedling stand 634 unit per $m^2$ in April 10 as compared to the other seeding dates. Furthermore, the dry weight of barley seeded in April 10 was heaviest at 146g $m^{-2}$. Rice yield was in 401kg $10a^{-1}$ in the April 10, and 517kg $10a^{-1}$ in the April 30, because of increased weeds caused by a low weed control. Effects of barley cover crop at same seeding with rice was ranged from 77~87% of control. The economic effect of barley as cover crop was analyzed to be increased by low herbicide using, despite of the slight decrease in rice yield during the period.

• Journal of the Korea Concrete Institute
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• v.24 no.2
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• pp.165-172
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• 2012

In this study, the physical, mechanical, structural, and environmental performances based on field measured data were evaluated to check the suitability of concrete for ecological preservation and cultivation of a hydrophilic environment. More specifically, the study is focused on developing an environmentally friendly functional concrete with river ecology restoration and natural river early formation capabilities. The mechanical performance evaluation results showed that the increase in mix rate of the PVA (Poly Vinyl Alcohol) reinforcement fibers and silica fume caused an increase in the strength. The optimal mix rate was found to be 0.05 volume % PVA fiber and approximately 10% silica fume. The frost resistance evaluation showed that superior performance was gained when 0.05 volume % PVA fiber and 15% silica fume was mixed simultaneously. In the structural performance evaluation, the bending strength was improved by 47.7% compared to plain concrete when mixed with 0.05 volume % PVA fiber. The flexural toughness also saw significant improvement. The environmental monitoring of field performance showed that grasses germinated most rapidly, but the growth of red poppies, a plant that germinates in the spring, was most active with passing of time. Coverage measurements in all of the monitoring locations found favorable coverage of over 95% after 12 weeks. The study results showed that the environmentally friendly functional concrete had outstanding environmental performance.

• Korean Journal of Weed Science
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• v.7 no.1
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• pp.3-11
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• 1987

The study was conducted to identify growth habit of Monochoria vaginalis gathered from three different locations (Suweon, Jeonju and Milyang). The plant height, number of leaves and dry weight of M. vaginalis gathered from three different locations were greatly affected by the seeding dates. The earlier the seeds of M. varginalis sown, the greater M. vaginalis grew, In general, the earlier seeding dates produced significantly longer plant height, number of leaves and dry weight than those of later seeding dates, showing no difference in the collection of weed seeds in different locality. The earlier seeding dates resulted in the earlier flowering, but the interval between dates of seeding and flowering decreased progressively as the seeding times were delayed. Seed production was not significant among three locations and but seeding date on June 15 produced th highest seed production as compared with other seeding times. No. of flowers and capsule per pot among yield components were two major factors affecting seed production.

• Korean Journal of Weed Science
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• v.7 no.1
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• pp.52-57
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• 1987

To know the effects of weeding periods (weeding from 12 days, 28 days and 42 days after seeding to harvest, and weeding from seeding to 14 days, 28 days and 42 days after seeding) and growing conditions such as transparent polyethylene film mulch (P.E. mulch) and bare soil on growth and yield of peanuts, "Yeongho-Tangkong" was planted on May 10, 1984. Under P.E. mulch, the number of weeds was higher, but the weed dry weight was lower than in bare soil by the middle of July. Sixty days after seedings, the length of main stems in weedy check plots was longer, but shoot dry weight was lower compared to weed free plot. In the correlation coefficients between weed dry weight and the shoot dry weight of peanut on July 14, the growth retardation of peanuts due to weeds was showed earlier under P.E. mulch than in bare soil. Shoot dry weight, shelling ratio, number of seeds per pod, 100 pod weight, and seed yield were higher under P.E, mulch compared to bare soil. But weed dry weight, length of branches, number of pod bearing branches, number of pods per square meters, and pod yield were similar between P.E. mulch and bare soil. Shoot dry weight of peanuts, length of branches, number of pod bearing branches, number of pods per square meters, pod yield, 100 pod weight, 100 seed weight, and seed yield in weed free plots from 28 days after seeding to harvest (28 DAS-Harvest) were higher compared to weed free plots from 42 DAS-Harvest. However, in the weed free plot from seeding to 42 days after seeding seed yield was lower than that of the continuous weeding plot due to lower number of pod bearing branches and number of pods per square meters. When weed was not controlled at the later growth stages of peanuts, reduction in seed yield due to weeds was greater in bare soil than that under P.E. mulch.

• Korean Journal of Weed Science
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• v.7 no.1
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• pp.45-51
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• 1987

This experiment was conducted to find out the critical competitive period and competitive ability of rice against red rice. Plant height and number of tillers of rice decreased as red rice competed with rice during active tillering stage. The maximum tillering stage of rice competed with red rice became about 10days earlier than those non-competed. Significant yield reduction of rice was observed in the plots competed for 20 days after transplating or longer. Such a yield reduction can be mainly attributed to the decrease in number of panicles per hill and grain number per panicle. In a replacement diagram for rice and red rice, their competition is turned out being antagonized. The relative yield total was considered lower than 1. Grain number, culm and panicle length of rice was not affected significantly by inter-specific competition. Rice grain yield reduction was highly correlated with the number of panicles of red rice. Three hundred panicles/$m^2$ of the red rice were necessary to reduce rice grain yield by 50% of the check plot.