• The Korean Journal of Ecology
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• v.17 no.3
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• pp.367-378
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• 1994

The germination responses of Echinochloa crus-galli (L.) Beauv. seeds to temperature were examined under the various thermal conditions. While almost all the seeds tested did not germinate immediately after collection, almost of the seeds which were stored for 7, 10, and 17 months showed very high germination percentages (85-95%) at their own constant temperatures between $16^{\circ}C\;and\;40^{\circ}C$. The total thermal time which was required for germination(10-70%) of Echinochloa crus-galli seeds ranged from 539Kh(degree Kelvin X hour) to 1,279Kh in accordance with the distribution function of thermal time, $F({\Theta})=1-[3D^{-3}({\Theta}-m+D)+1]^{-1/2}$, where m is 935Kh and D is 555Kh. Moist chilling treatment at $2^{\circ}C$ for 20 days increased the final germination percentage as well as the germination rate. In the increasing temperature(IT1 regime, E. crus-galli seeds started to germinate at $12^{\circ}C$. and showed greater germination rate with increasing temperatures, with the final germination percentage of 80%. On the other hand, in the decreasing temperature(DT1 regime, the seeds began to germinate at $12^{\circ}C$(10% germination) with the final germination percentage of 20%. An induced dormancy occurred at $4^{\circ}C$ in the DT regime.

• Current Research on Agriculture and Life Sciences
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• v.8
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• pp.9-18
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• 1990

Germinating ability of 54 weed species collected throughout Korea in 1987 and 1988 was determined in incubator at $25^{\circ}C$ for 15 days. The seeds of Echinochloa sp, collected from 70 different places throughout Korea, were classified by Yabuno's seed morphology method. Plant characters of two identified Echinochloa species, one having two subspecies were evaluated. SDS-PAGE(sodium dodecyl sulfate polyacrylamide gel electrophoresis) of seed protein assay was used to identify locally collected Echinochloa species classified by Yabuno's seed morphology method. 1. Out of 54 weed species collected, 31 species showed germination at 15 days after incubation, and 14 species showed over 50% and no germination was observed in 24 species, indicating that approximately 40 species had varied degree of germinating ability. 2. It was confirmed that two annual species of Echinochloa such as E. oryzicola and E. crus-galli occurred in Korea and one of which particularly E. crus-galli has two subspecies such as E. c. var. praticola and E. c. var. crus-galli. 3. E. oryzicola was distinguished from E. c. var crus-galli and E. c. var praticola by presence or absence of one major protein band in B zone. However, it was rather difficult to distinguish E. crus-galli species because they showed similar protein pattern.

• Weed & Turfgrass Science
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• v.4 no.2
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• pp.111-117
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• 2015

The equilibrium moisture contents (EMC) in seeds of four Echinochloa (E. crus-galli var. crus-galli, E. crus-galli var, echinata, E. crus-galli var. praticola, E. esculenta) were measured at $20^{\circ}C$ with equilibration over a series of lithium chloride solutions with relative humidities ranging from 0.11 to 0.8 to determine sorption isotherms and safe storage relative humidity. Standard seed sorption isotherm models i.e. modified Henderson, modified Chung-Pfost, modified Halsey, modified Oswin and Guggenheim-Anderson-deBoer (GAB) equations were adopted to evaluate the goodness of fit to sorption isotherms. This study indicated that EMC of seeds was significantly different in four Echinochloa species at various relative humidity. The modified Oswin equations for E. crus-galli var. crou-galli, E. crus-galli var, echinata, E. esculenta and GAB equation for E. crus-galli var. praticola were adequate models for the EMC data. Seeds of four Echinochloa species have monolayer moisture contents when stored at RH < 0.1. These results show that seed moisture isotherm model should be selected according to genetic variation.

• Korean Journal of Weed Science
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• v.13 no.1
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• pp.62-70
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• 1993

There was intraspecific variation in Echinochloa crus-galli var, crus-galli in response to quinclorac, showing that plan height and dry weight of a locally collected barnyardgrass(Chinjupi) from Chinju were 90.5 and 37.8% of the untreated control, while those of a locally collected one(Iripi) from Iri showed 19.1 and 14.4%, respectively. The normal distribution curve was obtained from frequency distribution of 89 rice cultivars as affected by the application rates of quinclorac at 30, 300, and 3,000g ai/ha. Protein patterns(SDS-PAGE) of two barnyardgrasses belonging to E, crus-galli var. crus-galli such as Iripi and Chinjupi were not affected by the quinclorac application, indicating that inhibition of enzyme and/or protein biosynthesis seems to be not the primary action target of quinclorac. Electronmicroscopic observation on the injured leaf of Iripi which is considered as a susceptible one showed prominent membrane disruption. Chuchungbyeo(rice variety) resulted in a greater inhibition of tomato growth than those from Chinjupi or Iripi, indicating a great amount of quinclorac discharged from rice root, Chinjupi which is relatively tolerant to quinclorac than Iripi, discharged more quinclorac causing a greater inhibition of tomato growth.

• The Korean Journal of Pesticide Science
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• v.3 no.2
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• pp.19-28
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• 1999

To investigate the physiological and biochemical differences between susceptible and tolerant species of Echinochloa species to the foliar applied cyhalofop-butyl and pyribenzoxim herbicides, herbicidal response, the rate of absorption, translocation and metabolism were studied. Among 148 individuals of Echinochloa species collected from 41 sampling sites in Korea which were classified into 7 geographical regions, based on morphological characteristics of plant and seed type, 46 lines were used for further studies. From them, E. crus-galli var. praticola collected from Hwanggan and E. crus-galli var. crus-galli collected from Namyangju were selected as the most susceptible species to cyhalofop-butyl and pyribenzoxim, respectively. Meanwhile, E. oryzicola(from Cheju) and E. crus-galli var. crus-galli(from Asan) were selected as tolerant species to cyhalofop-butyl and pyribenzoxim, respectively. Application of radio-labelled herbicides on the 1st leaf to both susceptible and tolerant Echinochloa species exhibited that the applied $^{14}C$-Cyhalofop-butyl and $^{14}C$-pyribenzoxim were more easily absorbed and translocated into stem tissues than root. Absorption of $^{14}C$-Cyhalofop-butyl increased rapidly at 1 h after application and reached the maximum at 12 h after application. However, the absorption rate of $^{14}C$-pyribenzoxim was not changed. Two metabolites from cyhalofop-butyl-treated plants and one metabolite from pyribenzoxim-treated plants were separated by TLC. The amount of metabolite 1 in cyhalofop-butyl-treated tolerant species was significantly higher than that in the susceptible one, suggesting differences in detoxification ability between susceptible and tolerant species.

• Korean Journal of Weed Science
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• v.17 no.2
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• pp.185-191
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• 1997

This experiment was conducted to determine the selective mechanism of cyhalofop-butyl ester on uptake, traslocation, and metabolism of the herbicide in both rice and Echinochloa crus-galli. Uptake and translocation of $^{14}C$-cyhalofop-butyl ester was higher in E. crus-galli than rice when treated to shoot. $^{14}C$-uptake by root of E. crus-galli increased rapidly at 30 minute after treatment and reached the maximum at 12 hoots after treatment. After that, uptake was leveled off. Uptake pattern in rice root was not significantly affected by the duration of herbicide treatment. In E. crus-galli, the absorbed $^{14}C$-cyhalofop-butyl ester seemed to be rapidly metabolized into free acid and the content of changed free acid was higher than rice.

• Korean Journal of Weed Science
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• v.17 no.4
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• pp.407-412
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• 1997

Allelopathic activity of methanol extract from medicinal plants was determined based on the inhibition of germination, shoot and root length of Echinochloa crus-galli. The response was depended on the source of extracts and concentrations. Of the 20 test plants tested, Cnidium officinale showed most inhibition according to germination, shoot and root length of E. crus-galli. Based on the plant parts, the root extract of C. officinale had more inhibitory effect on E. crus-galli than the stem+leaf extract. Phytotoxic effects of the root extract on E. crus-galli showed 75% inhibition of seed germination, 95% inhibition of shoot growth, and 100% inhibition of root growth at the concentration of 1g/petridish. Sequential partitioning of root extract with organic solvents with increasing polarity showed that the ethylacetate fraction had the greatest inhibitory effect on E. crus-galli. Germination was not inhibited at any rate of ethylacetate fraction but shoot and root growth, were significantly inhibited even at 2mg/petridish. This indicates that the most toxic phytotoxin present in the root extract may be moderate polar compound.

• Korean Journal of Weed Science
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• v.16 no.3
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• pp.171-175
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• 1996

Seed occurrence patterns of Echinochloa crus-galli (L) P. Beauv. and Monochoria vaginalis (Burm. f.) Presl. were investigated in irrigated and rainfed rice cultures. There was not much difference in seed population of E. crus-galli between irrigated and rainfed fields, but M. vaginalis occurred in about 1.6-fold greater number in rainfed fields. In seed distribution patterns under the two conditions, about 50% and 30% of E. crus-galli and M. vaginalis, respectively, were found in the uppermost 5cm layer. Under both conditions M. vaginalis was distributed to a depth of 25cm, but distribution of E. crus-galli was only 15cm deep. Early rice transplanting brought about greater emergence of the two weeds than optimal or late transplanting. Emergence of the weeds was significantly greater in single cropping system of rice than in double cropping systems of rice followed by barley and/or strawberry.

• Korean Journal of Weed Science
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• v.8 no.1
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• pp.9-14
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• 1988

Three varieties of Echinochloa crus-galli (L.) Beauv. and five collections different in gross morphology from the E. crus-galli species were obtained in a lowland rice field located in Jukjeol-Ri, Soyang-Myeon, Wanju-Kun, Jeonbug to compare the ecological and physiological characteristics. There were great variations in seed dormancy, relative growth rates, days required to panicle emergence and panicle morphology among the collections. On the basis of the cluster analysis using the different characteristics, the collections were divided into three groups; E. crus-galli var. frumentaceae and its two ecotypcs, E. crus-galli var. echinata and its two ecotypes, and E crus-galli var. crus-galli and its one ecotype. There were differential responses in percent germination and post-germination growth of the collections to butachlor (2-chloro-2', 6'-diethyl-N-butoxymethyl acetanilide).

• Korean Journal of Weed Science
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• v.32 no.1
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• pp.44-51
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• 2012

This study was conducted to predict the rice yield loss and to determine the economic threshold levels for direct-seeding flooded rice cultivation from competition to the most serious perennial weeds, Cyperus serotinus Rottb. and Echinochloa crus-galli L. The rice yield loss model of C. serotinus and E. crus-galli were predicted as Y = 560 kg/(1+0.001883x), $r^2$=0.933, and Y = 507 kg/(1+0.001734x), $r^2$=0.867, respectively. In comparison of the competitiveness represented by parameter ${\beta}$, it was 0.001883 in C. serotinus and 0.001734 in E. crus-galli, respectively. Economic thresholds calculated using Cousens' equation were negatively related with the competitiveness of weed. The economic thresholds of C. serotinus and E. crus-galli were 15.5 and 2.3 plants per $m^2$, respectively.