• Korean Journal of Weed Science
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• v.8 no.2
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• pp.103-113
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• 1988

• Korean Journal of Weed Science
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• v.16 no.3
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• pp.210-220
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• 1996

Ten-day-old seedlings of the oxyfluorfen-tolerant and -susceptible rice cultivars with barnyardgrass, a typical susceptible weed were soaked in oxyfluorfen at $10^{-6}M$ for 2 hrs kept for 24 hrs in the dark, and exposed to light for 0, 2, 4, or 6 hrs to investigate changes in the activity and isozyme of antioxidative enzymes. The activities of antioxidative enzymes of APOX, CAL, POX, NR, GR, MDAR and SOD in the tolerant and susceptible rice cultivate themselves didn't show any difference but the activity in the susceptible barnyardgrass was very low in comparison with rice cultivars. The activity of lipoxygenase tended to be some slightly higher in the susceptible rice cultivars and barnyardgrass than in the tolerant rice cultivars. The activities of MDAR, POX, GR and SOD, antioxidative enzymes, were higher in the tolerant rice cultivars than in the susceptible rice cultivars and barnyardgrass after the treatment of oxyfluorfen. After the treatment of oxyfluorfen, in the change of POX isozyme, the activity of C band in the tolerant rice cultivars increased with increased concentration but it didn't in the susceptible rice cultivar. The activity of B band decreased slightly at $10^{-4}M$ in the susceptible barnyardgrass. Isozyme of GR, SOD and AO by the treatment of oxyfluorfen, the activity of each band between the tolerant and susceptible rice cultivars showed no difference but GR isozyme C band was disappeared in the susceptible barnyardgrass at $10^{-4}M$. In the change of esterase isozyme resulting from the treatment of oxyfluorfen, the activities of B, C and D bands decreased more in the susceptible rice cultivars than in tolerant rice cultivars, and A band was disappeared in the susceptible barnyardgrass at $10^{-4}M$.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.5
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• pp.405-412
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• 1993

This experiment was conducted to investigate the effects of water depths on seedling stand and early growth of califonia rice varieties, S201, M202, A301, Italico livorno and Korean variety, Hwaseongbyeo, and barnyardgrass (Echinochloa crus-galli) The coleoptile length of rice was longer with deep water depth while for the radicle length shorten. As water depth was increased, the percentage of seedling stand were decreased slightly in rice, while sharply increased in barnyardgrass. Plant height of rice with increasing water depth were longer, whereas that of barnyardgrass reduced significantly with weaker. Tiller number of rice and barnyardgrass were significantly reduced as water depth increased. Dry matter weight and healthy score of rice seedling at 35DAS were highest in 7.5cm water depth followed saturated moisture, 15, and 22.5cm water depth, while for barnyardgrass those were especially negatively affected by deep water depth. These results showed that the seedling stand and early growth of barnyardgrass was highly suppressed by deeper water levels compared with rice. Rice cultivars which are showes growth characteristics in deeper water levels at early growth stage were Italico livorno and S201 in Japonica / Indica.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.1
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• pp.22-28
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• 2001

The induction of enzymes and the accumulation of their end products associated with self-defense mechanism in rice were investigated. When rice leaves were irradiated with UV light, activities of diterpene cyclase, phenylalanine ammonia-lyase (PAL), and cinnamic acid 4-hydroxylase (CA4H) were induced and rice phytoalexin, momilactone A was accumulated. The content of p-coumaric acid in rice leaves was closely correlated with self-defense or allelopathic potential against barnyardgrass. UV-challenged rice leaves gave rise to the inhibition of barnyardgrass growth.

• The Korean Journal of Pesticide Science
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• v.4 no.3
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• pp.89-92
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• 2000

A series of 5-(2-metllyl-2-alkylindallyl)cyclohexane-1,3-diones were synthesized and evaluated for herbicidal activities in a green house. Under submerged paddy conditions, those compounds showed high herbicidal activity against barnyardgrass with good tolerance on rice.

• Current Research on Agriculture and Life Sciences
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• v.17
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• pp.65-70
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• 1999

This study was conducted to develop a simple selection method for herbicide-resistance weeds. Two methods, designated "seedling method" and "stem node method" were employed for screening of barnyardgrass against propanil and butachlor. In the seedling method, shoot and root growth of barnyardgrass were significantly inhibited at quarter of the recommended herbicide rate, while in the stem node method, the similar inhibition was obtained at half of the recommended rate. Thus, it was concluded that the seedling method is more simple and quick method to evaluate response of barnyardgrass to propanil and butachlor compared to stem node method.

• Current Research on Agriculture and Life Sciences
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• v.20
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• pp.65-70
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• 2002

This study was conducted to investigate allelopathic potential of various crosses of rice cultivars using their inhibitory effect on barnyardgrass growth under field conditions, and to determine PAL activity and phenolic compounds involved in phenylpropanoid pathway from selected crosses of rice cultivars. Under field conditions, Kouketsumochi, Woo co chin yu possessed higher allelopathic potential inhibiting over 90% of barnyardgrass growth. Crosses of Kouketsumochi/Woo co chin yu, Dongjinbeyo/Kouketsumochi, Dongjinbeyo/Woo co chin yu showed over 80% inhibitory effects on barnyardgrass growth. The highest PAL activity, $63.46{\mu}kats/kg$ proteins was detected in Kouketsumochi which is the most important enzyme in phenylpropanoid pathway and also higher PAL activity in crosses with Kouketsumochi. Content of cinnamate was $2.64{\mu}g/g$ f.w. in Kouketsumochi which was 2 to 5 times higher than other rice cultivars tested, indicating that higher PAL activity resulted in more cinnamate. The similar trends in cinnamate content and PAL activity were observed in crosses of rice cultivars with Kouketsumochi.

• Korean Journal of Weed Science
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• v.9 no.1
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• pp.16-27
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• 1989

The six barnyardgrass [Echinochloa oryzicola (vasing.) Vasing.] and seventeen barnyardgrass [Echinochloa crus-gadli (L.) Beauv.] accessions, which were collected national widely in 1986 and selected two times through 1987. To study different growth response due to herbicide, pyrazolate, bifenox, quinclorac, the experiment was conducted with herbicide agar culture without nutrients, 1. Albinistic discoloration due to pyrazolate was more sensitive in E, crus-galli than E. oryzicola and among barnyardgrass accessions, Kumi, Ichon-A, Ichon-B, Boun-B and Kwangju-B were rather susceptible than Gyongju, Ansong, Boun-A, Jongju-A and Kwangju-A. 2. Twisting and growth retardation due to bifenox was less sensitive in E. oryzicola with less intra-specific variations than in E. crus-galli. Among E. crus-galli accessions, Boun-B, Ansong, Ichon-A, Ichon-B, Wonju and Kwangju-B were particulary susceptible, and Jinyang, Jongju-B, Jongju-A, Daejon, Kurye and Kwangju-A were tolerant as much as E. oryzicola. 3. Growth retardation and withering to dead due to quinclorac was more sensitive in E. oryzicola with less intra-specific variations than in E. crus-galli. Among accessions of E. curs-galli, Boun-A, Iri, Jongju-A, Jongju-B, Kwangju-A and Kwangju-B were rather similar suseptible to E, oryzicola than kimhae, Gyongju, Kumi, Wonju, Ichon-A, Ichon-B and Ansong. 4. Most accession of E. oryzicola was tolerant to both pyrazolate and bifenox, while susceptible to quinclorac. Among other accessions of E. crus-galli, Kurye, Kimhae, and Daejon were tolerant to all experimented herbicides, and Iri, Jongju-A, Jongju-B, and Kwangju-A were only tolerant to both pyrazolate and bifenox, while Kumi, Wonju, Ichon-A, Ichon-B, Boun-B and Kwangju-B were only tolerant to quinclorac.

• Korean Journal of Weed Science
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• v.16 no.1
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• pp.54-63
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• 1996

This study was conducted to investigate the anatomical and ultrastructural responses of the oxyfluorfen-tolerant and -susceptible rice cultivars with barnyardgrass, a typical susceptible weed by oxyfluorfen and the herbicides having similar mode of action treatment. After the treatment of $10^{-5}M$ oxyfluorfen, the tolerant rice cultivars no showed the structural damage of leaf surface, but the susceptible rice cultivate was damaged in the wax and the susceptible barnyardgrass was even destroyed in the tissue irregularly. Also in the susceptible rice cultivars and barnyardgrass the thickness of leaf blade was greatly decreased. The anatomical change was not observed in the tolerant rice cultivars but epidermal cells, mesophyll cells and bundle sheath cells were badly broken in the susceptible rice cultivars and barnyardgrass and especially after 24 hours of the treatment the structure of susceptible rice cultivars was completely disintegrated. The irregularity of chloroplast shape and the distortion of chloroplast envelope were generally observed and the starch tended to decrease by oxyfluorfen treatment regardless of rice cultivars. Such a structural damage were appeared more badly in the susceptible rice cultivars and bamyardgrass than in the tolerant rice cultivars. By the treatment of diphenyl ether herbicides, the thickness of leaf blade greatly reduced in the order of oxyfluorfen > acifluorfen > bifenox > oxadiazon, and the susceptible rice cultivars showed more reduction than the tolerant rice cultivars. Especially, the susceptible rice cultivars showed that the leaf structure was badly broken down with damage epidermal cells and bundle sheath cells.

• The Korean Journal of Pesticide Science
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• v.2 no.3
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• pp.52-63
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• 1998

A novel quinolineoxadiazoles, substituted the carboxylic acid group with 1,2,4-oxadiazole radicle, of KSC-16960 and related compounds were evaluated to examine the herbicidal activity, crop injury and residual effect of after-vegetable crops compared with those of quinclorac (3,7-dichloro-8-quinolinecarboxylic acid), of which use is now banned because of its residual activity to some succeeding vegetable crops. KSC-16960 showed 2- and 3-leaf stages of barnyardgrasses effectively controlled by more than 95 and 90%, respectively, at a rate of 6.25 g/ha. The dose of KSC-16960 controlled 4- and 5-leaf stages of barnyardgrasses by more than 90% were found to be 50 g and 100 g/ha, respectively. The selectivity of KSC-16960 between direct-seeded rice and barnyardgrass was approximately 2-fold higher than that of quinclorac when they were treated to the soil. The selectivity indices of KSC-16960 and of quinclorac between 1-leaf stage of direct seeded rice and 5-leaf stage of barnyardgrass were 44 and 23, respectively, and those between 1-leaf stage of direct seeded rice and 4-leaf stage of barnyardgrass were almost 2-fold higher. Application of KSC-16960 with bentazone exhibited an additive controlling effect on several weed species, but that of quinclorac exhibited an antagonistic effect. With pyrazosulfuron-ethyl, on the other hand, both application of KSC-16960 and quinclorac showed additive interactions. Under a greenhouse condition, the residual activity of KSC-16960 to succeeding tomato plants was approximately 4-fold lower compared to that of quinclorac. KSC-16960 could be substituted for quinclorac, if it will be made some more improvement for reducing residual activity.