• Korean Journal of Weed Science
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• v.9 no.2
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• pp.141-148
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• 1989

Echinochloa species collected from 13 places of Korea appeared to be morphologically very different. They were classified by Yabuno's seed morphology method into two species such as Echinochloa oryzicola and Echinochloa crus-galli which have two varieties such E. crus-galli var, cuss-galli and var, praticola. Among them, E. oryzicola was morphologically similar to Oryza sativa, but it had small leaf length with straight from, no awn, late heading and little interspecific variance. As compared with E. oryzicola, E. eras-galli var. crus-galli, and var, praticola showed a great variance exerting so difficulty in classifing them morphologically, particularly a great variance in leaf length, tiller number and grain size. E. oryzicola species showed the more sensitive response to butachor and thiobencarb herbicides than E. eras-galli var. praticola and var. eras-galli. However, E. eras-galli var. praticola was themore sensitive one to pretilachloa herbicide than such as E. oryzicola and E. eras-galli var. eras-galli, indicating that Echinochloa species might have a selective response to the annual herbicides tested.

• 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.

• 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.5 no.4
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• pp.181-186
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• 2016

Three Echinochloa species inhabit various crop fields with different soil moisture conditions. Therefore, a growthpouch test was conducted to investigate adaptive diversity of six Echinochloa species, three from Korea and three from USA, toosmotic stress by assessing shoot and root growths. Echinochloa crus-galli var. praticola showed the greatest tolerance to osmoticstress in both root ($GR_{50}=1316.3g\;PEG\;L^{-1}$) and shoot ($GR_{50}=212.2g\;PEG\;L^{-1}$) growths, while Korean E. oryzicola was mostsensitive to osmotic stress in both root ($GR_{50}=116g\;PEG\;L^{-1}$) and shoot ($GR_{50}=126.2g\;PEG\;L^{-1}$) growths. Root to shoot (R/S) ratioof Echinochloa crus-galli var. praticola increased with increasing osmotic stress, while that of Korean E. oryzicola decreased, suggestingthat R/S ratio is closely related to osmotic stress tolerance in Echinochloa species. Our results clearly demonstrate that E. crus-galli var.praticola maintains high R/S ratio even under high osmotic stress, which enables this species to well adapt to dry upland condition. Incontrast, while E. oryzicola fails to maintain sufficiently high R/S ratio, resulting in poor adaptability to dry upland condition.

• Korean Journal of Weed Science
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• v.16 no.3
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• pp.194-199
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• 1996

Seed size and days required to reach specific growth stages were determined for Echinochloa crus-galli (L.) P. Beauv. varieties which are major grass species found in Korean paddy field and the results were compared with E. frumentacea (Roxb.) Link. In addition, responses of the Echinochloa species on preemergence herbicides (molinate, esprocarb, and mefenacet) were investigated with respect to time of application. One thousand seed weight of E. crus-galli var. oryzicola was about 3 times heavier than that of var. praticola, but was not significantly different that of E. frumentacea. Days requited to reach the 2.5 leaf-stage (LS) were 11, 13, and 14 days after seeding for E. frumentacea, E. crus-galli var. oryzicola, and E. crus-galli var. praticola, respectively. E. crus-galli var. praticola was more sensitive to molinate, esprocarb and mefenacet than var. oryzicola and the sensitivity of both the varieties decreased as the time of application LS was delayed. However, there was no great difference in the response for E. frumentacea when applied between 1.5 and 3.0 LS. In thiocarbamate hebicides esprocarb was more active to Echinochloa species than molinate and the higher the active ingredient of the herbicides, the greater was the activity to Echinochloa species. Differential susceptibility of Echinochloa species to the herbicides was not related to the seed size, but to the early growth stages at the time of herbicide application which were affected by the seed size.

• 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 CROP SCIENCE
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• v.41 no.2
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• pp.131-138
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• 1996

Soil crusting and hardening as a result of drying after rainfall were examined in relation to seedling emergence by employing five rice varieties (Italiconaverneco, Dadazo, and Galsaekggarakshare, Dongjinbyeo and Sumjinbyeo) and two barnyardgrass species (E. crus-gallj var. oryzjcola and E. crus-galli var. praticola). Sandy loam, loam, and silty loam soils were used. The artificial rainfall of 0, 20 and 40mm were applied after sowing and covering with 4cm soil. Air temperature and solar radiation averaged over 9 days after seeding was 31.3$^{\circ}C$ and 16.9MJ /m$^2$, respectively. Soil strength increased rapidly by drying after artificial rainfall, being greater in soils with greater amount of clay and artificial rainfall. Soil crust was formed on the surface with artificial rainfall in all soils tested. However, soil crust was exfoliated in silty loam and loam soil, and lifted as seedlings emerge. Seedling emergence of rice varieties was decreased by rainfall treatments. Sumjinbyeo and Dongjinbyeo showed much poorer seedling emergence especially in sandy loam soil than the other varieties. Poor seedling emergence of these varieties might have been caused by delayed seedling emergence which had made them expose to greater soil strength. Seedling emergence of barnyardgrasses showed no differences among soil textures and rainfall treatments, because they emerged rapidly before soil crusting and hardening were proceeded enough to hamper seedling emergence. Seedling emergence of Sumjinbyeo and Dongjinbyeo decreased with increasing soil strength averaged over 3 days to 5 days after seeding, being lowered to 80% at soil strength of 1.0kg/cm$^2$ and to 50% at 1.7kg/cm$^2$. Emergence speed of barnyardgrasses was faster than rice varieties, and E. crus-galli var. oryzjcola than E. crus-galli var. praticola. Italiconaverneco and Dadazo showed faster emergence in rice varieties. Galsaekggarakshare showed slower emergence speed than these two varieties with similar seedling emergence percentage. The greater and faster elongations of mesocotyl and incomplete leaf in rice, and of mesocotyl in barnyardgrass were the characteristics responsible for higher seedling emergence rate in the environment examined.