Competition effects with mixed stands of wheat and kochia (Kochia scoparia) biotypes resistant and susceptible to acetolactase synthase inhibitor herbicides

Greenhouse experiments were conducted to compare the competitive ability of sulfonylurea resistant and susceptible kochia (Kochia scoparia L. Schard) compared to wheat. The results of several replacement series experiments indicate that wheat was the dominant competitor, and an average of one wheat plant reduced resistant kochia yield per plant equal to the effect of 4.8 resistant kochia or 5.4 susceptible kochia plants. Intraspeciflc competition was more important than interspecific competition for wheat, whereas the reverse was true for the resistant and susceptible kochia. The results of the niche differentiation index (NDI) indicate that wheat and either resistant or susceptible kochia are only partly limited by the same resources. The resistant and susceptible kochia, however, are limited by the same resources.

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Growth Characterization of Kochia (Kochia scoparia) with Substitutions at Pro197or Trp574Conferring Resistance to Acetolactate Synthase–Inhibiting Herbicides

Weed Science ◽

10.1614/ws-d-12-00116.1 ◽

2013 ◽

Vol 61 (2) ◽

pp. 267-276 ◽

Cited By ~ 15

Author(s):

Anne Légère ◽

F. Craig Stevenson ◽

Hugh J. Beckie ◽

Suzanne I. Warwick ◽

Eric N. Johnson ◽

...

Keyword(s):

Acetolactate Synthase ◽

Dry Weight ◽

Variable Response ◽

Kochia Scoparia ◽

Replacement Series ◽

Mixed Stands ◽

Population Total ◽

Factors Affecting ◽

Herbicide Resistant ◽

Growth Characterization

Over 90% of Canadian kochia populations are resistant to acetolactate synthase (ALS)– inhibiting herbicides. We questioned whether the target site–based resistance could affect plant growth and competitiveness. Homozygous F2herbicide-resistant (HR) kochia plants with an amino acid substitution at Trp574(sources: Alberta [AB], Saskatchewan [SK], and Manitoba [MB]), or Pro197(MB, AB with two populations) were grown in replacement series with homozygous F2herbicide-susceptible (HS) plants from the corresponding heterogeneous population (total: six populations). In pure stands, growth of HR plants from AB and SK was similar to that of HS plants, regardless of mutation; conversely, MB2-HR plants (Trp574Leu) developed more slowly and were taller than MB2-HS plants. Final dry weight of HR plants in pure stands was similar across all six populations, whereas that for HS plants in pure stands and HR–HS plants in mixed stands (50–50%) varied with population. Results for AB and SK populations suggest little impact of either ALS mutation on kochia growth, whereas those for MB lines would suggest an unidentified factor (or factors) affecting the HS, HR, or both biotypes. The variable response within and between lines, and across HS biotypes highlights the importance of including populations of various origins and multiple susceptible controls in HR biotype studies.

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RELATIVE COMPETITIVENESS BETWEEN MAIZE HYBRIDS AND WILD POINSETTIA

Revista Caatinga ◽

10.1590/1983-21252021v34n206rc ◽

2021 ◽

Vol 34 (2) ◽

pp. 298-309

Author(s):

LEANDRO GALON ◽

RICARDO LUIS GABIATTI ◽

FELIPE JOSÉ MENIN BASSO ◽

ANDRÉ LUIZ RADÜNZ ◽

FRANCISCO WILSON REICHERT JÚNIOR ◽

...

Keyword(s):

Interspecific Competition ◽

Leaf Area ◽

Intraspecific Competition ◽

Competitive Ability ◽

Dry Mass ◽

Plant Population ◽

Grain Production ◽

Replacement Series ◽

Maize Hybrids ◽

Chlorophyll Index

ABSTRACT Maize is one of the main cereals cultivated worldwide and wild poinsettia is among the weeds that cause damage in grain production. The objective of this study was to evaluate the relative competitive ability of maize hybrids in the presence of a wild poinsettia biotype through experiments in replacement series. In preliminary experiments, it was determined the plant population in which the dry mass becomes constant. For the maize hybrids ‘Agroeste’, ‘Morgan’, ‘Nidera’, and ‘Velox’, as well as the wild poinsettia, the population was 20 individuals vase-1. Subsequently, experiments were carried out in replacement series in different combinations of species that varied the relative proportions (100:0, 75:25, 50:50, 25:75, and 0:100%). The analysis of the species' competitiveness was carried out using diagrams applied to the replacement experiments and by the relative competitiveness indexes. The height (PH), chlorophyll index (CI), leaf area (LA), and the shoot dry mass (DM) of the plants were evaluated 50 days after emergence. There was competition between the maize hybrids and the wild poinsettia; both were negatively affected, regardless of the proportion of plants, causing reductions in the species' PH, CI, LA, and DM. The competition between maize and wild poinsettia occurs for the same resources in the environment, and interspecific competition caused greater damage to maize and wild poinsettia than intraspecific competition. In general, it was observed that only the hybrids ‘Nidera’ and ‘Velox’ were more competitive than the wild poinsettia.

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Competitivity of the common-bean plant relative to the weed alexandergrass [Brachiaria plantaginea (link) hitch.]

Scientia Agricola ◽

10.1590/s0103-90162003000200009 ◽

2003 ◽

Vol 60 (2) ◽

pp. 259-268 ◽

Cited By ~ 14

Author(s):

Telma Passini ◽

Pedro Jacob Christoffoleti ◽

Inês Fumiko Ubukata Yada

Keyword(s):

Common Bean ◽

Interspecific Competition ◽

Intraspecific Competition ◽

Block Design ◽

Niche Differentiation ◽

Quantitative Approach ◽

Pure Stand ◽

Replacement Series ◽

Design Data ◽

Randomized Block Design

Methodologies of competitive interaction quantification between weeds and crops are not widely elucidated and compared in the literature. The competitive ability of common-bean (Phaseolus vulgaris) relative to alexandergrass (Brachiaria plantaginea) was assessed and two approaches of replacement series experiment analysis were compared. The response of the species to the presence of each other at different densities and proportion was evaluated. Replacement series at total densities of 625, 816 and 1,111 plants m-2 were performed at the proportions of common-bean:alexandergrass of 100:0 (pure stand of common-bean), 75:25, 50:50, 25:75 and 0:100% (pure stand of alexandergrass), at four replicates in a randomized block design. Data analyses were performed by the qualitative compared to the quantitative approach. The quantitative approach provided larger number of information than did the qualitative approach, and indicated that there was intraspecific competition among common-bean plants, and a minimum of interspecific competition from alexandergrass. There was no intraspecific competition among alexandergrass plants, being the crop effect on the weed larger than the effect among alexandergrass plants. The ecological niche differentiation was partial, since the crop intraspecific competition was larger than the interspecific, and the last one was negligible, at the same time that the weed interspecific competition was larger than the intraspecific. Common-bean, as a competitor species, is superior to alexandergrass.

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The Role of Allelopathy in Buckwheat (Fagopyrum sagittatum) Inhibition of Canada Thistle (Cirsium arvense)

Weed Science ◽

10.1017/s004317450008084x ◽

1995 ◽

Vol 43 (1) ◽

pp. 70-74 ◽

Cited By ~ 16

Author(s):

Steven R. Eskelsen ◽

Garvin D. Crabtree

Keyword(s):

Interspecific Competition ◽

Intraspecific Competition ◽

Plant Biomass ◽

Niche Differentiation ◽

Canada Thistle ◽

Mutual Inhibition ◽

Replacement Series ◽

Mutual Antagonism ◽

Inhibition Data

A replacement series experiment was conducted in the field to quantify the interaction between Canada thistle and buckwheat, and to determine if allelopathy was the mechanism of interference. Plant biomass data indicated that buckwheat only responded to intraspecific competition and not interspecific competition from Canada thistle. Canada thistle responded to interspecific competition from buckwheat plants but not to intraspecific competition. The absence of one of the interspecific competition components (no measurable effect of Canada thistle density on buckwheat) indicates that the value for niche differentiation is probably greater than unity, signifying that there is no mutual antagonism between buckwheat and Canada thistle. Because allelopathy is one mechanism that causes mutual inhibition, data do not support the hypothesis that buckwheat interferes with Canada thistle by allelopathy.

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Foraging niche partitioning in sympatric seabird populations

Scientific Reports ◽

10.1038/s41598-021-81583-z ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Christina Petalas ◽

Thomas Lazarus ◽

Raphael A. Lavoie ◽

Kyle H. Elliott ◽

Mélanie F. Guigueno

Keyword(s):

Interspecific Competition ◽

Niche Partitioning ◽

Niche Differentiation ◽

Sympatric Species ◽

Foraging Strategies ◽

Gps Tracking ◽

Seabird Species ◽

Foraging Range ◽

Common Murre ◽

Prey Items

AbstractSympatric species must sufficiently differentiate aspects of their ecological niche to alleviate complete interspecific competition and stably coexist within the same area. Seabirds provide a unique opportunity to understand patterns of niche segregation among coexisting species because they form large multi-species colonies of breeding aggregations with seemingly overlapping diets and foraging areas. Recent biologging tools have revealed that colonial seabirds can differentiate components of their foraging strategies. Specifically, small, diving birds with high wing-loading may have small foraging radii compared with larger or non-diving birds. In the Gulf of St-Lawrence in Canada, we investigated whether and how niche differentiation occurs in four incubating seabird species breeding sympatrically using GPS-tracking and direct field observations of prey items carried by adults to chicks: the Atlantic puffin (Fratercula arctica), razorbill (Alca torda), common murre (Uria aalge), and black-legged kittiwake (Rissa tridactyla). Although there was overlap at foraging hotspots, all species differentiated in either diet (prey species, size and number) or foraging range. Whereas puffins and razorbills consumed multiple smaller prey items that were readily available closer to the colony, murres selected larger more diverse prey that were accessible due to their deeper diving capability. Kittiwakes compensated for their surface foraging by having a large foraging range, including foraging largely at a specific distant hotspot. These foraging habitat specialisations may alleviate high interspecific competition allowing for their coexistence, providing insight on multispecies colonial living.

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Competitiveness of alexandergrass or Bengal dayflower with soybean

Planta Daninha ◽

10.1590/s0100-83582010000300008 ◽

2010 ◽

Vol 28 (3) ◽

pp. 515-522 ◽

Cited By ~ 7

Author(s):

A.C.R. Dias ◽

S.J.P. Carvalho ◽

L.W. Marcolini ◽

M.S.C. Melo ◽

P.J. Christoffoleti

Keyword(s):

Competitive Ability ◽

Dry Mass ◽

Total Density ◽

Weed Species ◽

Replacement Series ◽

Commelina Benghalensis ◽

Randomized Design ◽

Full Flowering ◽

Completely Randomized Design ◽

Soybean Plants

Weeds compete with field crops mainly for water, light and nutrients, and the degree of competition is affected by the weed density and the intrinsic competitive ability of each plant species in coexistence. The objective of this research was to compare the competitiveness of alexandergrass (Brachiaria plantaginea) or Bengal dayflower (Commelina benghalensis) in coexistence with soybean, cv. M-Soy 8045. A factorial experiment (2 x 5) with two weed species and five competition proportions was carried out in a completely randomized design with four replicates. Proportions were based on a replacement series competition design, always maintaining the total density of four plants per 10 L plastic pots, which corresponded to 60 plants m ². The weed-crop proportions were: 0:4; 1:3; 2:2; 3:1; 4:0; that corresponded to the proportion of 100, 75, 50, 25 and 0% of soybean plants and the opposite for weeds, B. plantaginea or C. benghalensis plants. Leaf area, shoot dry mass of the weeds and soybean and number of soybean trifoliate leaves were evaluated when the soybean reached the phenologic stage of full flowering. B. plantaginea was a better competitor than soybean plants. Otherwise, C. benghalensis revealed a similar competitive ability that of the soybean. In both cases, there were evidences that intraspecific competition was more important.

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Initial growth and competitive ability of yellow nutsedge and irrigated rice

Planta Daninha ◽

10.1590/s0100-83582013000400007 ◽

2013 ◽

Vol 31 (4) ◽

pp. 813-821 ◽

Cited By ~ 3

Author(s):

N.R. Westendorff ◽

D. Agostinetto ◽

A.R. Ulguim ◽

A.C. Langaro ◽

L. Thürmer

Keyword(s):

Leaf Area ◽

Competitive Ability ◽

Growth Cycle ◽

Rice Crop ◽

Initial Growth ◽

Rice Cultivars ◽

Replacement Series ◽

Irrigated Rice ◽

Yellow Nutsedge ◽

Dry Biomass

Weeds cause significant reduction in the irrigated rice crop yield. Cyperus esculentus (yellow nutsedge) is adapted to irrigate environment. Information on the competitive ability of the weed to the culture, and their environmental adaptation, are scarce. In this study, we sought to determine the initial growth and competitive ability of yellow nutsedge and irrigated rice, as a function of cultivar growth cycle. Initial growth and competition studies were conducted in a randomized complete design in a greenhouse in the agricultural year 2010/11. For the initial growth study, the treatments consisted of a factorial combination of a biotype of yellow nutsedge and two rice cultivars in the function of the vegetative cycle (BRS Querência: early cycle - IRGA 424: intermediate cycle) and six evaluation times (10, 20, 30, 40, 50, and 60 days after emergence). Were evaluated: plant height, leaf area, aboveground dry biomass and root dry biomass. In the competitive ability study in the replacement series, the cultivar BRS Querência (early cycle) and yellow nutsedge were utilized and tested in different proportions of competition (100:0, 75:25, 50:50, 25:75, and 0:100). Were evaluated leaf area and aboveground dry biomass. In general, rice cultivars have an adaptive value equivalent to yellow nutsedge. IRGA 424 cultivar has less height than weed, becoming the weed control more important in this cultivar. For rice crop, intraspecific competition is more important, whereas for the weed, interspecific competition is the most pronounced.

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Competitiveness of ALS inhibitors resistant and susceptible biotypes of Greater Beggarticks (Bidens subalternans)

Planta Daninha ◽

10.1590/s0100-83582011000200024 ◽

2011 ◽

Vol 29 (2) ◽

pp. 457-464 ◽

Cited By ~ 13

Author(s):

F.P. Lamego ◽

R.A. Vidal ◽

N.R. Burgos

Keyword(s):

Competitive Ability ◽

Germination Rate ◽

Rio Grande ◽

Rio Grande Do Sul ◽

Replacement Series ◽

Relative Growth Rates ◽

Temperature Conditions ◽

Als Inhibitors ◽

The University ◽

Continuous Use

The continuous use of ALS-inhibiting herbicides has led to the evolution of herbicide-resistant weeds worldwide. Greater beggarticks is one of the most troublesome weeds found in the soybean production system in Brazil. Recently, a greater beggarticks biotype that is resistant (R) to ALS inhibitors due to Trp574Leu mutation in the ALS gene was identified. Also, the adaptive traits between susceptible (S) and R to ALS inhibitors biotypes of greater beggarticks were compared. Specifically, we aimed to: (1) evaluate and compare the relative growth rates (RGR) between the biotypes; (2) analyze the seed germination characteristics of R and S biotypes under different temperature conditions; and (3) evaluate their competitive ability in a replacement series study. The experiments were conducted at the University of Arkansas, USA, in 2007 and at Universidade Federal do Rio Grande do Sul (Federal University of Rio Grande do Sul), Brazil, in 2008. Plant proportions for replacement series studies were respectively 100:0, 75:25, 50:50, 25:75 and 0:100, with a total population of 150 plants m-2. There was no difference in RGR between R and S biotypes. The R-biotype germination rate was lower than that of the S biotype. However, at low temperature conditions (15 ºC), the reverse was observed. In general, there is no difference in the competitive ability between R and S greater beggarticks biotypes.

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Phosphorus effects on competitive interactions of smooth pigweed (Amaranthus hybridus) and common purslane (Portulaca oleracea) with lettuce (Lactuca sativa)

Weed Science ◽

10.1017/s0043174500089463 ◽

1998 ◽

Vol 46 (3) ◽

pp. 307-312 ◽

Cited By ~ 17

Author(s):

Bielinski M. Santos ◽

Joan A. Dusky ◽

William M. Stall ◽

Donn G. Shilling ◽

Thomas A. Bewick

Keyword(s):

Competitive Ability ◽

Organic Soils ◽

Weed Species ◽

Population Densities ◽

Replacement Series ◽

Amaranthus Hybridus ◽

Extractable P ◽

Common Purslane ◽

Smooth Pigweed ◽

Water Extractable

Replacement series studies were conducted under controlled conditions to determine the effect of phosphorus (P) rates and population densities on the competitiveness of smooth pigweed and common purslane with lettuce. Densities were 2, 4, and 8 plants per 113 cm2, whereas P rates were 0, 0.4, and 0.8 g PL−1soil. A P-deficient Histosol (0.3 mg water-extractable P L−1soil) was used. High P fertility enhanced the competitive ability of lettuce in smooth pigweed-lettuce mixtures. Smooth pigweed was not responsive to P rates. However, luxurious P consumption by smooth pigweed occurred, reducing the amount of the nutrient available for lettuce absorption. In common purslane-lettuce mixtures, the weed was responsive to P rates, increasing its competitive ability, whereas no increase in lettuce competitive ability was observed. Both weed species were more competitive than lettuce. Competition for P appears to be the main mechanism of common purslane interference on lettuce grown in low-P organic soils. Alternative fertilization strategies (i.e., banded applications) may reduce the effect of smooth pigweed on lettuce.

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Removal of Soil Microbes Alters Interspecific Competitiveness of Epichloë Endophyte-Infected over Endophyte-Free Leymus chinensis

Microorganisms ◽

10.3390/microorganisms8020219 ◽

2020 ◽

Vol 8 (2) ◽

pp. 219

Author(s):

Hui Liu ◽

Jing Chen ◽

Tianzi Qin ◽

Xinjian Shi ◽

Yubao Gao ◽

...

Keyword(s):

Interspecific Competition ◽

Competitive Ability ◽

Soil Microbes ◽

Leymus Chinensis ◽

Competitive Advantages ◽

Soil Environment ◽

Plant Soil ◽

Epichloë Endophytes ◽

Colonization Rates ◽

Epichloë Endophyte

Epichloë endophytes may not only affect the growth and resistances of host grasses, but may also affect soil environment including soil microbes. Can Epichloë endophyte-mediated modification of soil microbes affect the competitive ability of host grasses? In this study, we tested whether Epichloë endophytes and soil microbes alter intraspecific competition between Epichloë endophyte-colonized (EI) and endophyte-free (EF) Leymus chinensis and interspecific competition between L. chinensis and Stipa krylovii. The results demonstrated that Epichloë endophyte colonization significantly enhanced the intraspecific competitive ability of L. chinensis and that this beneficial effect was not affected by soil microbes. Under interspecific competition, however, significant interactions between Epichloë endophytes and soil microbes were observed. The effect of Epichloë endophytes on interspecific competitiveness of the host changed from positive to neutral with soil microbe removal. Here higher mycorrhizal colonization rates probably contributed to interspecific competitive advantages of EI over EF L. chinensis. Our result suggests that Epichloë endophytes can influence the competitive ability of the host through plant soil feedbacks from the currently competing plant species.

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