Conyza sumatrensis var. leiotheca (Compositae: Astereae), a New Combination for a Common Neotropical Weed

Pruski, John F.; Sancho, Gorka

doi:10.3417/1055-3177(2006)16[96:csvlca]2.0.co;2

Cited by 23 publications

(21 citation statements)

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“…The highest value of genetic identity reported in our study (I = 0.8293) was between C. canadensis and C. sumatrensis. The highest value of molecular similarity between C. canadensis and C. sumatrensis is in agreement with the highest similarity reported based on morphological parameters (Pruski & Sancho, 2006;Vladimirov, 2009).…”

supporting

confidence: 87%

“…In contrast, C. canadensis occurs only in the Southern Region, particularly in Rio Grande do Sul State (Lazaroto et al, 2008). Identification keys (Pruski & Sancho, 2006) typically define characteristics that can be used to differentiate the three Conyza species. In C. canadensis, the leaves are yellowish green and glabrous, whereas in C. bonariensis and C. sumatrensis, they are greyish green and very hairy.…”

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confidence: 99%

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Genetic admixture in species of Conyza (Asteraceae) as revealed by microsatellite markers

et al. 2017

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ABSTRACT. The distinction among Conyza canadensis, C. bonariensis, and C. sumatrensis is a challenge for weed science. In the current study, primers for microsatellite (SSR) loci were used to investigate the molecular divergence among the three species, the genetic structure of the populations at the molecular level and the level of genetic admixture among Conyza plants from southern Brazil. Twelve primers amplified well-defined DNA segments for all 88 samples of the three Conyza species. The estimated proportion of SSR polymorphic loci, number of alleles, and mean expected heterozygosity were higher in samples of C. bonariensis than in samples of C. sumatrensis or C. canadensis. Conyza canadensis was the species with the lowest molecular diversity. High genetic divergence was observed among the three species. The well-defined ancestral groups for each species led to the identification of samples of Conyza with ancestral genomes from the three species. Hybridization events between pairs of these species may have occurred in crop fields from southern Brazil. The high molecular diversity in resistant biotypes of C. sumatrensis indicated that these biotypes have a high potential to colonize new areas, which increases its potential as a weed.Keywords: horseweed, molecular divergence, SSR loci.Mistura genética em espécies de Conyza (Asteraceae) reveladas por marcadores microsatélites RESUMO. A identificação das espécies Conyza canadensis, C. bonariensis e C. sumatrensis tem sido desafiadora para a ciência das plantas daninhas. No presente estudo, primers para locos microssatélites (SSR) foram utilizados para investigar a divergência molecular entre as três espécies; mostrar como as populações estão geneticamente estruturadas em nível molecular e avaliar o nível de mistura genética entre as plantas de Conyza no Sul do Brazil. Doze primers amplificaram segmentos de DNA bem definidos em todas as 88 amostras das três espécies. A proporção estimada de locos SSR polimórficos, o número de alelos, e a heterozigosidade média esperada foram mais altos nas amostras de C. banariensis do que nas demais. C. canadensis foi a espécie com menor diversidade molecular. Divergência genética alta foi observada entre as três espécies. A formação de grupos ancestrais bem definidos para cada espécie levou à identificação de amostras de Conyza com genoma ancestral das três espécies. A ocorrência de hibridização entre as três espécies pode ter ocorrido nas lavouras do Sul do Brasil. A diversidade molecular alta em biótipos resistentes de C. sumatrensis indicou que estes biótipos têm um alto potencial para colonizar novas áreas, o que agrava seu potencial como planta daninha.Palavras-chave: buva, divergência molecular, locos SSR.

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confidence: 87%

Section: Introductionmentioning

confidence: 99%

Genetic admixture in species of Conyza (Asteraceae) as revealed by microsatellite markers

et al. 2017

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“…Conyza sumatrensis , or Conyza albida Willd. ex Spreng., is considered to be a native species of South America, but it has spread throughout the tropical and subtropical areas in all continents (Thebaud & Abbott ; Pruski & Sancho ). Conyza canadensis is found mainly in colder areas, such as those with altitudes that are >1000 m, while C. bonariensis usually is limited to warmer areas in lower altitudes (≤400–500 m), a habitat similar to that of C. sumatrensis , which also grows in sunny, warm environments (Vladimirov ).…”

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confidence: 99%

Conyza sumatrensis: A new weed species resistant to glyphosate in the Americas

Santos

Oliveira

Constantin

et al. 2014

Weed Biology and Management

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Recent reports of weed‐control failures after the use of glyphosate led to suspicion about the selection of resistant biotypes of Conyza at locations in west and north Paraná, Brazil. Plants were collected, identified as Conyza sumatrensis and subsequently evaluated for possible resistance to glyphosate in four stages of weed development. The experiments were carried out in a greenhouse by combining biotypes, stages of development and a range of glyphosate doses. All the suspected biotypes were collected from locations in Cascavel, Toledo, Assis Chateaubriand, Tupãssi and Campo Mourão with a history of glyphosate use in burndown and in glyphosate‐resistant soybean for at least the four previous years and were compared to a susceptible biotype (São Jorge do Ivaí) with no previous history of herbicide use. The doses of glyphosate ranged from 0 to 5760 g ae ha−1. The biotypes were considered as resistant if two combined criteria were present (resistance factor > 1 and the rate required to achieve 80% control is >720 g ha−1). The results provided evidence that there is a marked difference in the level of control of older plants and also confirmed the presence of some resistant biotypes. For applications at the first stage of development, two biotypes that were resistant to glyphosate were identified (Cascavel‐1 and Tupãssi‐6). For applications in the second stage of development, beyond the biotypes that were found in the first stage, three other biotypes were considered as resistant: Toledo‐5, Assis Chateaubriand‐7 and Floresta‐10. However, for applications at the third and fourth stages, all the biotypes were considered as resistant.

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“…(Asteraceae), synonym of Erigeron L., is abundant in Tunisia, represented by four species, viz. sumatrensis is the second variety [2]. ex.…”

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confidence: 99%

Chemical Composition and Antimicrobial and Allelopathic Activity of Tunisian Conyza sumatrensis (Retz.) E.Walker Essential Oils

Mabrouk

Salah

Elaissi

et al. 2013

Chemistry & Biodiversity

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Conyza sumatrensis (Retz.) E.WALKER (Asteraceae) is a spontaneous annual herb, fairly widespread throughout Tunisia, which has rarely been studied or valued in any sector. Essential oils were obtained by hydrodistillation of different parts (flower heads, leaves, stems, and roots) of C. sumatrensis plants, which were collected in autumn (November 2007) at the flowering stage in the area of Monastir, Tunisia. In total, 98 compounds, representing 88.1-99.3% of the oil composition, were identified by GC-FID and GC/MS analyses. The root essential oil was distinguished by its high content in acetylenes (matricaria ester, 4; 74.3%), while those from flower heads and leaves were dominated by oxygenated sesquiterpenes (61.1 and 50.3%, resp.). The oils of C. sumatrensis from Tunisia belonged to a matricaria ester/caryophyllene oxide chemotype. All the oils were evaluated for antibacterial, antifungal, and allelopathic activities. The results indicate that the leaf oil exhibited significant in vitro antibacterial activity against Enterococcus faecalis, Staphylococcus aureus, and Proteus mirabilis and that the C. sumatrensis oils isolated from the aerial parts presented high mycelia-growth inhibition of Candida albicans and the filamentous fungi tested. Moreover, the essential oils of the different plant parts inhibited the shoot and root growth of Raphanus sativus (radish) seedlings. Indeed, the inhibition of the hypocotyl growth varied from 28.6 to 90.1% and that of the radicle from 42.3 to 96.2%.

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Conyza sumatrensis var. leiotheca (Compositae: Astereae), a New Combination for a Common Neotropical Weed

Cited by 23 publications

References 6 publications

<b>Genetic admixture in species of <i>Conyza</i> (Asteraceae) as revealed by microsatellite markers

<b>Genetic admixture in species of <i>Conyza</i> (Asteraceae) as revealed by microsatellite markers

Conyza sumatrensis: A new weed species resistant to glyphosate in the Americas

Chemical Composition and Antimicrobial and Allelopathic Activity of Tunisian Conyza sumatrensis (Retz.) E.Walker Essential Oils

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