• Korean Journal of Weed Science
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• v.31 no.2
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• pp.160-166
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• 2011

The purposes of this study were to analyze the weediness potential associated with 'Vitamin A enforced rice' and to evaluate the relationships between growth characteristics and environmental adaption related to survival ability in the natural environment. 'Vitamin A enforced rice', 'Nagdong', donor variety of 'Vitamin A enforced rice' and three other varieties were used for this study. The 'Vitamin A enforced rice' was experimented according to ratio of ripened grain, shattering of grain, germination traits, germination ratio of low temperature, emergence ratio after wintering, ratio of viviparity, and growth ratio after ratooning ability. 'Vitamin A enforced rice' was not significant between 'Nagdong' and other varieties in seven characters. Germination ratio was similar of Vitamin A enforced rice' and 'Nagdong', but average germination ability of was different at low temperature. Also, shattering of grain and germination ratio of alternating temperature were significant between 'Nagdong' and other varieties. These results suggested that the relationships between growth characteristics and environmental adaption in 'Vitamin A enforced rice' could be applied to the stability of weediness potential and biosafety guide in GM rice.

• Korean Journal of Weed Science
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• v.31 no.2
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• pp.183-191
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• 2011

Weeding effect was investigated based on the leaf stages to several different herbicide treatments for an integrated weed management of herbicide resistant Echinochloa oryzoides to ACCase and ALS inhibitors in a rice field. Efficacy of soil-applied herbicide treatments before resistant E. oryzoides occurred was very effective. Pentaxazon 5% SC showed over 98% of weeding effect although E. oryzoides were emerged 31 days after the treatment. Until the leaf stage of 2.5, five herbicides, azimsulfuron carfenstole 1.05% GR, bensulfuron-methyl benzobicyclone mefenacet 24.52% SC, bensulfuron-methyl fentrazamide 7% SC, bensulfuron-methyl mefenacet oxadiargyl 21.6% SC and mefenacet pyrazosulfuron-ethyl 3.57% GR showed perfect weeding effect. Benzobicyclone mefenacet penoxulam 21.5% SC and mefenacet pyrazosulfuron-ethyl 3.57% GR were effective at the leaf stage of 3.0. It is very important to select the right herbicides for timing and their systematic application for controlling of E. oryzoides resistant to ACCase- and ALS-inhibitors.

• Korean Journal of Weed Science
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• v.30 no.1
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• pp.34-42
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• 2010

Competitive ability, allelopathy, made the common ragweed (Ambrosia artemisiifolia var. elatior ) one of the most dangerous weeds in Korea. The aim of this research was to evaluate the role of common ragweed as test species under laboratory bioassay and glasshouse conditions. Inhibition effect of the leaf extract was higher than that of stem and root parts extracts on germination and seedling growth of weeds. The 5% concentration of leaf extract of common ragweed inhibited the germination rate of Echinochloa crus-galli, Digitaria sanguinalis and Cyperus microiria by 68.3, 74.6 and 87.3%, respectively, as compared to the control. Generally, increasing incorporation concentration inhibited seedling growth of weeds. Incorporation of 5% common ragweed residue significantly reduced the plant length of E. crus-galli, D. sanguinalis and C. microiria by 48, 63 and 68%, respectively, as compared to the control. Also, the values of dry weight were 72, 78 and 71%, respectively. Contrarily, the emergence rate of soybean and corn was not affected by the incorporation of 5% concentration of common ragweed residue. However, the dry weight was inhibited by 37 and 28%, respectively. These results suggest that common ragweed had the ability to control some weed species using toxic compounds like natural herbicide.

• Korean Journal of Weed Science
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• v.11 no.3
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• pp.205-210
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• 1991

The freezing resistance of Eleocharis kuroguqai was evaluated in artifical and natural freezing conditions in relation to tuber size, depth of tuber burial and soil moisture conditions. Osmotic potential of immature and mature tuber of E. kuroguqai before hardening was -12.1 and -23.5 bar, respectively, but decreased to -61. 0 and -67.1 bar after 120-day hardening period. Percent survival of E. kuroguqai tubers during the winter period was 13% and 67% in dry and moist moisture conditions at burial of 5cm depth, but all tubers were survived in the three moisture conditions employed when buried at 25cm depth. Greater decrease of osmotic potential was observed in tubers buried at 5cm depth than tubers buried at 25cm depth, resulting in greater freezing resistance in the former. Large tuber was more susceptable to freezing temperatures than small tuber.

• Journal of Plant Biotechnology
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• v.37 no.3
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• pp.305-312
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• 2010

During a last decade, the introduced traits in commercialized GM crops have been diversified from a simple trait such as herbicide resistance gene or insectresistance gene which are related to the crop production into more complicated traits such as modification of fatty acid or essential amino acid composition, modified coloring pattern of flower. In addition, it was investigated that several other GM crops bearing more refined traits expected to lead next generation are also awaiting for risk assessment (RA) or under field test for the preparation of RA in the near future. These GM crops include abiotic stress resistance including drought or cold, increased biomass, production of bioethanol or diesel, production of pharmaceuticals or functional materials for industrial. In particular, in 2008 and 2009, it was reported that the highest number of GM crops for molecular farming are under developed in laboratory or green house level in all the world. Likewise, in Korea, 171 events from 49 plant species are under developed to introduce several important traits. At present, about 10 events are under field test to select elite lines for RA application. For the first time, herbicide resistance turfgrass developed by Korean research team has been submitted for RA and currently under requested for additional data. Moreover, GM rice resistant to leaf roll (folder) disease is expected as a next event to be submitted for RA application.

• The Korean Journal of Pesticide Science
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• v.10 no.2
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• pp.107-116
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• 2006

Korean entomopathogenic nematode strain were evaluated against white grubs, Popillia quadriguttata, Ectinohoplia rufipes and Phyllopertha diversa in laboratory. In addition we examined the efficacy of entomopatogenic nematode, Heterorhabditis sp. KCTC 0991BP strain against white grubs in Seaside Golf Club in Gimpo, Gyeonggii and persistence of entomopatogenic nematode in fairway of Anyang Benest Golf Club in Gunpo, Gyeonggii. In laboratory Heterorhabditis bacteriophora Hamyang strain showed 95% mortality against Popillia quadriguttata. H. bacteriophora Hamyang strain and Heterorhabditis sp. KCTC 0991BP induced 80% mortality against 3rd instar of Ectinohoplia rufipes. However, the letter showed only 60% mortality against Phyllopertha diversa. White grub density was reduced to 39% by the application of Heterorhabditis sp. KCTC 0991BP at the rate of $2.24{\times}10^9$ infective juveniles $ha^{-1}$ compared with control in Seaside Golf Club. Heterorhabditis sp. KCTC 0991BP persisted for two months at $5{\sim}10$ cm soil depth but not persisted at $0{\sim}5$ cm soil depth for the same periods when applied at the rate of $2.47{\times}10^9$ infective juveniles $ha^{-1}$.

• Korean Journal of Weed Science
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• v.12 no.4
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• pp.368-373
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• 1992

The effect of alachlor treatment on protein synthesis was studied. Protein synthesis was inhibited by $1{\times}10^{-4}$ M and $1{\times}10^{-3}$M of alachlor 5.8% and 86.5%, respectively, while did not occur blow $1{\times}10^{-5}$M alachlor. Soluble protein of alachlor treated oat root tips was examined by polyacrylamide gel electrophoresis. The proteins extracted from oat root tips showed that they were made up of subunits blow 100 kd polypeptides by SDS-PAGE. As compared to control, high molecular proteins(above 47 kd) were inhibited of oat root treated with alachlor, while low molecular proteins(below 23 kd) were increased. Two-D gels showed that alachlor caused decrease(1-6 spots) or increase(7-10 spots) in number of polypeptides on silver staining. The intensity of some polypeptides of soluble proteins (molecular mass of 83 kd : 1, 2 spots, 70 kd : 3, 4 spots, and 47.5 kd : 5, 6 spots) decreased in alachlor treatment, whereas the intensity of other peptide bands (20 kd : 7 spot and 16 kd : 8, 9, 10 spots) increased. Oat root tip proteins present in the neutral zone are masked by diffusing of major proteins, but proteins in acid zone are resolved minor proteins.

• Korean Journal of Weed Science
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• v.30 no.4
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• pp.429-436
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• 2010

Herbicidal activity and characteristics of chrysophanic acid were investigated in semi-field condition. At early and middle post-emergence, Trifolium repens appeared to be very susceptible to chrysophanic acid of $2,000{\mu}g\;mL^{-1}$. However, herbicidal activity of chrysophanic acid of $2,000{\mu}g\;mL^{-1}$ estimated by visual injury to Artemisia princeps was not caused considerable phytotoxicity. Also by foliar application, the concentration of crysophanic acid for effectively control to Polygonum aviculare was much higher than $2,000{\mu}g\;mL^{-1}$. Herbicidal activity of chrysophanic acid to Echinochloa crus-galli, Cypres difformis, Setaria viridis, Digitaria sangguinalis, Bidens tripartita by foliar application was more effective at concentration ranges from 4,000 to $6,000{\mu}g\;mL^{-1}$. These results suggest that chrysophanic acid demanded for higher than $2,000{\mu}g\;mL^{-1}$ to successful weed control in the field condition.

• Korean Journal of Weed Science
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• v.30 no.4
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• pp.380-389
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• 2010

Transgenic herbicide-resistant sweet potato plants [Ipomoea batatas (L.) Lam.] produced through a biolistic transformation were used in this study. The objective of this research was to find out a rapid and reliable assay method for confirming glufosinate-ammonium resistance. The techniques tested include whole-plant bioassay, one leaf bioassay, and leaf disk bioassay. Parameters investigated in this study were leaf injury and ammonium accumulation at 1 and 5 days after treatment of glufosinate-ammonium. In the leaf disk bioassay, leaf injury of the transgenic line 7171 was 1.9-fold less affected by glufosinate-ammonium than the wild type. The leaf injury of 7171 in one leaf and whole-plant bioassays was 59- and 92-fold less affected by glufosinate-ammonium, respectively, compared with that of the wild type. Leaf disk, one leaf, and whole-plant bioassays showed that ammonium accumulation of the 7171 was 2 to 20-, 4 to 43-, and 6 to 115-fold less affected by 0.5-5 mM glufosinate-ammonium than that of the wild type. All three bioassays successfully distinguished the resistance from the transgenic lines, but one leaf bioassay is the simplest and quickest. Leaf injury and ammonium accumulation were the same in leaves 1, 3, 5, 7, and 10 of 3 mM glufosinate-ammonium treated plants or nontreated plants. The one leaf bioassay was chosen as the standard procedure for future confirmation of resistance in transgenic sweet potato because it is a rapid and reliable assay.

• Korean Journal of Weed Science
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• v.16 no.4
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• pp.301-308
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• 1996

In this study, a propagation characteristics of green kyllinga(Kyllinga brevifolia var. leiolepsis H.) was investigated. Two to three rhizomes(1st rhizome) arised from the basal part of main shoot at 4th leaf stage and were grown to extend on the soil surface. Then new shoots(lst tillers) emerged from every node of the 1st rhizome. Second rhizomes also arised from the basal part of lst tiller at the time of 4th leaf openning. With such a regularity, 5th rhizomes and about 688 shoots were produced from one plant during one year-cultivation without competition under the natural condition. The degree of vegetative growth and seed formation was 3 times and 2.5 times higher in rhizomeoriginated plant than in that from seed, respectively. The amount of seed formation and the 1000 seeds weight was highest in one planted on June 1 and Aug. 1, respectively. Short-day treatment of less than 14hr appeared to be necessary for the induction of flowering and it was effective as treated not during germination but since at least 2 leaf stage of green kyllinga. Each shoot individually responded to short-day. When plants were exposed to short-day (9hr, day / 15hr, night) treatment at the stage of 2-3 leaves, more than 7 cycles were required for flowering induction. Bolting in main shoot occurred after emergence of 4 leaves under the short-day condition. Exogenous $GA_3$ slightly accelerated the velocity of bolting only in short-day condition.