• Title/Summary/Keyword: Echinochloa glabrescens

Search Result 8, Processing Time 0.021 seconds

Effect of Fertilizer and Shading on Emergence of Echinochloa glabrescens, Monochoria vaginalis and Cyperus difformis (Echinochloa glabrescens, Monochoria vaginalis 및 Cyperus difformis 발아(發芽)에 미치는 비료시용(肥料施用)과 차광(遮光)의 영향(影響))

  • Kim, Jong-Seog
    • Korean Journal of Weed Science
    • /
    • v.8 no.1
    • /
    • pp.33-36
    • /
    • 1988
  • The emergences of Echinochloa glabrescens, Monochoria vaginalis, and Cyperus difformis seeds were little affected by fertilizer application. All shading treaments resulted in decrease in emergence of E. glabrescens, while shading up to 67% slightly stimulated emergence of M. vaginalis and C. difformis. The peak emergence of E. glabrescens was at two week after sowing in the full sunlight, 31, and 52% shading, but no peak emergence at the 67% shading. Emergence peaks of C. difformis were observed during 6 to 8 weeks after sowing for all shading levels employed.

  • PDF

Effects of Elevated $CO_2$ and Temperature on Competition between Rice and Echinochloa glabrescens Seedlings

  • Kim, Han-Yong
    • Plant Resources
    • /
    • v.1 no.1
    • /
    • pp.43-48
    • /
    • 1998
  • The objective of this study was to determine how elevated $CO_2$ and temperature affected early growth and competition between direct seeded rice (Oryza sativa) and a common paddy weed (Echinochloa glabrascens). By using temperature gradient chambers. Rice and E. glabrescens were grown for 5 weeks at ratios of 1:0. 3:1 and 0:1 at three temperatures ($16.4^{\circ}C,\;19.8^{\circ}C,\;and\;22.2^{\circ}C$) and either in ambient (361ppm) or elevated (566ppm) $CO_2$. For both species. elevated $CO_2$ had no effect on mainstem leaf number while air temperature had a slight positive effect which was greater in E. glabrescens than rice. With elevated $CO_2$ rice leaf area index and plant height increased alightly in all species combinations but no increases were observed for E. Glabuescens. For rice in all combinations. elevated $CO_2$ tended to increase the rot and total biomass much more than any other growth parameters: the increases in root and total biomass resulting from elevated $CO_2$ ranged from 16% to 40%. depending on air temperature. At the lowest temperature, the decrease in rice biomass in combination with E. glabrescens was significantly greater at elevated $CO_2$ (18%) than ambient $CO_2$ (3%). At the highest temperature, however, the decrease in rice biomass at elevated $CO_2$ (22%) was less than that at ambient $CO_2$ (36%). The competitive ability of rice as measured by the decrease in biomass when grown in combination with E. glabrescens depended strongly on root growth and/or allocation. These results suggest that at higher temperatures elevated $CO_2$ could enhance the competitive ability of direct seeded rice during early growth. However, at lower temperatures. the competitive ability of E. glabrescens seems to be greater.

  • PDF

Effect of Standing Water and Cultivation on Emergence of Echinochloa glabrescens (Echinochloa glabrescens 발아(發芽)에 대한 담수심(湛水深)과 경운(耕耘)의 영향(影響))

  • Kim, Jong-Seog
    • Korean Journal of Weed Science
    • /
    • v.8 no.1
    • /
    • pp.28-32
    • /
    • 1988
  • The effects of standing water and cultivation frequency on emergence of Echinochloa glabrescens Munro ex. Hook were determined at varied seeding methods under simulated field conditions for 4 months. In soil-incorporated seeding method total emergence for 4 months was highest in saturated condition followed by 4, 2, and 8cm standing water, whereas total emergence of seeds sown at the soil surface was highest at 2cm standing water followed by 4cm, saturated soil, and 8cm standing water. Within 2 weeks the emergence was highest at 4cm and lowest at 2cm standing water with the soil-incorporated seeding, but the seeds sown at the soil surface with 2cm standing water resulted in the highest emergence. Ratio of emergence within 2 weeks over total emergence during 4 months was lowest at 2cm standing water in the soil incorporation, indication that 2cm standing water would be the critical water level for E. glabrescens. Since most of the seedling was emerged within 2 weeks just before cultivation, the emergence pattern was little affected by cultivation at each standing water level.

  • PDF

Taxonomic Review of the Genus Echinochloa in Korea (II): Inferred from Simple Sequence Repeats

  • Lee, Jeongran;Kim, Chang-Seok;Lee, In-Yong
    • Weed & Turfgrass Science
    • /
    • v.3 no.3
    • /
    • pp.190-195
    • /
    • 2014
  • Echinochloa (L.) P. Beauv. includes some of the noxious weeds, causing a serious yield loss when they are dominant in the fields. Identification of the Echinochloa is very difficult because many interspecific and intraspecific forms of the species are found. However, it is important to identify the species exactly and to know the genetic diversity of the species for effective weed management. This study was conducted to identify and summarize the Echinochloa species by comparing the genetic variation and relationship among Korean Echinochloa species using SSR. The genetic diversity of 107 individuals, including seven species were assessed using five SSR markers. UPGMA dendrogram generated two clades (I and II) and clade II divided again into two subclades (II-1 and II-2) whereas the model based genetic structure proposed four subpopulations. The two subpopulations were corresponded to clades I and II-1 and the other two were arranged to clade II-2 of the UPGMA dendrogram. We have concluded that E. colona and E. glabrescens might have not distributed in Korea. The biological varieties, praticola and echinata, of E. crus-galli should be treated as E. crus-galli. Korean Echinochloa should be summarized with four species, i.e., E. oryzicola, E. crus-galli, E. esculenta, and E. oryzoides.

Adaptation Strategy in Dry Matter and Seed Production of Rice and Weed Species (벼와 잡초(雜草)의 건물생산(乾物生産) 및 종자생산(鐘子生産) 특성(特性)에 따른 환경적응(環境適應) 전략(戰略))

  • Kim, Soon-Chul;Moody, Keith
    • Korean Journal of Weed Science
    • /
    • v.9 no.3
    • /
    • pp.183-200
    • /
    • 1989
  • An experiment was conducted at the greenhouse of the International Rice Research Institute in 1987 to find out the character of dry matter production, the potential seed production ability and the ecological and physiological strategies to adaptation. For these, two rice cultivars, IR64(lowland rice) and UPLRi-5(upland rice), and seven weed species were used ; Echinochloa glabrescens Munro ex Hook. f., E. cress-galls ssp. hispidula (Retz.) Honda, E. colons (L.) Link, Monochoria vaginalis (Burin. f.), Ludwigia octovalvis Jacq.) Raven, Fimbristylis miliacea Vahl and Cyperus difformis L. Adaptation strategies of weed species varied by species. However, they had efficient seed production strategy through different ways. In general, sedge weed species (F. miliacea and C. difformis) produced great amount of seeds at the expense of seed size through greater ratooning ability and low relative dry weight for flowering. For broadleaved weed species, greater number of descendants were obtained through high plasticity and low relative dry weight for flowering (M. vaginalis) or greater growth ability through effective photosynthetic efficiency (L. octovalvis). Grass weed species, on the other hand, produced their seeds through effective growth (net assimilation rate and relative growth rate), high ratooning ability (except E. crus-galls ssp. hispidula) or low relative dry weight to maximum dry weight for flowering (E. glabrescens). The harvest indices of the weed species were considerably lower than those of rice. Fimbristylis miliacea had the greatest ratooning ability followed by C. difformis, E. colons and E. glabrescens. The greatest seed productivity was recorded by C. difformis (279, 000) and L. octovalvis (268,000) while rice produced the least number of seeds (1300-6100). Log seed weight had a negative linear relationship with log seed number (y=6.30-1.48X, $R=-0.965^{**}$). For all species plant plasticity response was not directly correlated with mortality response.

  • PDF

Germination and Seedling Development of Rice and Echinochloa Species (벼와 피의 발아(發芽) 및 유묘발달(幼苗發達) 양상(樣相))

  • Kim, Soon-Chul;Moody, Keith
    • Korean Journal of Weed Science
    • /
    • v.9 no.2
    • /
    • pp.108-115
    • /
    • 1989
  • An experiment was carried out at the International Rice Research Institute in 1987 to understand the seed germination and seedling development of rice and Echinochloa species. The percentage germination of rice cultivars(IR64 for lowland-type and UPLRi-5 for upland-type) was extremely high(>90%) regardless of temperature while that of Echinochloa species ranged from 10 to 80% depending on the species. Among these, E. crus-galli ssp. kispidula had the lowest germination with less than 20% at the high temperatures ($30^{\circ}C$, $35^{\circ}C$) and about 45% at the low temperature ($25^{\circ}C$). Original seed weight gradually decreased with time white root and shoot weight increased for both rice and Echinochloa species. However, increase in root and shoot weight did not compensate for the loss of stored carbohydrate during the experimental period. The root of E. glabrescens grew from the seed on the opposite side of the shoot while for rice it grew from the same side of the seed as the shoot. Echinochloa glabrescens had a leaf blade-like expanded first leaf that contained chlorophyll while rice had an incomplete first leaf that had no leaf blade and no chlorophyll. Due to this E. glabrescens could grow independently 2 to 3 days earlier than rice.

  • PDF

Types of Weed Community in Transplanted Lowland Rice and Relationship between Yield and Weed Weight in Weed Communities (논 잡초의 군락형 종류와 군락형별 잡초발생과 수도수량과의 관계)

  • S. C, Kim;Keith, Moody
    • KOREAN JOURNAL OF CROP SCIENCE
    • /
    • v.25 no.3
    • /
    • pp.1-8
    • /
    • 1980
  • Eight different weed community types growing in association with transplanted rice were identified in the experimental fields used in these studies. The Importance Value (LV.) of weed species growing in association with rice changed with time. The I. V. of Echinochloa glabrescens Munro ex Hook f. increased from 40 days after transplanting (DAT) until heading and then, decreased from heading to maturity of rice. However, the LV. of Monochoria vaginalis (Burm.) Pres!. and Echinochloa crus-galli ssp. hispidula (Retz.) Honda increased from 40 DAT to maturity while Scirpus maritimus L. decreased from 40 DAT. There was a high negative correlation between grain yield and weed weight at rice heading in all weed communities. The competitive ability of rice against weeds varied depending upon weed species. The highest yield decrease due to weed competition was obtained from the E. crus-galli ssp. hispidula-S. Maritimus community. Forty-two percent yield reduction was caused by competition of 100g dry weight of weeds per square meter of this community type at rice heading. The yield decrease for the same amount of weeds was 10% for the E. glabrescens community, 15% for the M vaginalis community and the M vaginalis-Scirpus supinus L. community and 21% for the M vaginalis-E. glabrescens-Fimbristylis littoralis Gaud.-S. maritimus community type.

  • PDF

Germination of Two Rice Cultivars and Several Weed Species (벼와 수종(數種) 논잡초(雜草)의 휴면성(休眠性)과 발아성(發芽性))

  • Kim, Soon-Chul;Moody, Keith
    • Korean Journal of Weed Science
    • /
    • v.9 no.2
    • /
    • pp.116-122
    • /
    • 1989
  • An experiment was carried out at the International Rice Research Institute in 1987 to understand the seed dormancy and germination habit of rice and several weed species. The germinability of the weed seeds just after harvest was variable depending on the species and ranged from 0 to 72%. Two rice cultivars, IR64(lowland type) and UPLRi-5(upland type) had higher than 95% in germination ability throughout the experimental period due to the fact that the rice seeds came from the harvest of the previous season and dormancy had already been overcome. The length of the storage period needed to overcome dormancy at room temperature($25{\pm}2^{\circ}C$) was about 50 days for Echinochloa glabrescens Munro ex Hook, f., more than 60 days for E. crus-galli ssp. hispidula (Retz.) Honda and 20 days for Ludwigia octovalvis(Jacq.) Raven. Seeds of E. colona(L.) Link, Monochoria vaginalis(Burm. f.) Presl, Fimbristylis miliacea(L.) Vahl and Cyperus difformis L. appeared to have no dormancy. Among the nine species M. vaginalis had the lowest germination of less than 1% throughout the experimental period. However, its seed germinated easily when planted in soil. The low germinability of E. glabrescens, E. crus-galli ssp. hispidula and L. octovalvis just after harvest could be overcome through pretreatment of seeds either by soaking in nitric acid(0.1N) for 1 day or removal of the hull in the grass species, the nitric acid treatment being superior. The results imply that germination habit of weed species varied depending on the species through their differential dormancy period or differential germination strategy.

  • PDF