Morphological characterization of Conyza blakei, Conyza bonariensis var. bonariensis, Conyza sumatrensis var. sumatrensis and Conyza lorentzii in the southeast of Buenos Aires (Argentine).

Abstract

Morphological characterization of Conyza blakei, Conyza bonariensis var. bonariensis, Conyza sumatrensis var. sumatrensis and Conyza lorentzii in the southeast of Buenos Aires (Argentine). The genus Conyza Less. includes ruderal species, which grow of ruderal habitat, roadsides and railways. They have also been cited as pasture weeds, annual and perennial crops under direct sowing (SD) systems, adapting to these slightly disturbed environments since they are sensitive to soil removal. The taxonomic identification of Conyza species linked to morphological characters is difficult in vegetative stages, since this genus has highly related and polymorphic species. With the objective of morphologically characterizing Conyza blakei, C. bonariensis var. bonariensis, C. lorentzii and C. sumatrensis var. sumatrensis were recorded 19 morphological characters (12 vegetative and 7 reproductive) qualitative and quantitative, in 35 plants of each species. These characters were analyzed by Multivariate Analysis (Analysis of Components and Main Coordinates). The morphological characterization made it possible to detect phenotypic differences between the Conyza species analyzed. The analysis of main coordinates allowed to differentiate the species both at a reproductive and vegetative level, while the analysis of main components only allowed to differentiate the species in reproductive stage.

Taxonomic resolution of fleabane species (Conyza spp.) based on morphological and molecular markers and their dispersion across soybean-cropping macroregions and seasons in Brazil

“…Overall, the traits related to reproductive structures were the most stable variables in our study and were very consistent with those in other studies (De Ulzurrun et al 2018; Hao et al 2009; Thébaud and Abbott 1995). However, quantitative traits such as plant height, number of leaves, and leaf angle were quite variable, even though they showed large contributions to the total variance in the PCA (Figure 5).…”

“…Leaf color, cotyledon width, and number of teeth were not stable traits in our study but were recognized as key traits to distinguish Conyza spp. in Argentina (De Ulzurrun et al 2018). Thus, we adopted a more conservative approach by selecting only phyllary color, involucre shape, and capitulescence and inflorescence type as reliable markers to be combined with molecular data.…”

Conyza bonariensis’ Resistance to Glyphosate, Diclosulam, and Chlorimuron: Confirmation and Alternative Control for the First Case of Multiple and Cross-Resistance in Uruguay

“…A screening study was carried out using the collected seeds, with glyphosate, diclosulam, and chlorimuron each being applied at their recommended doses individually to all Conyza biotypes. From this initial study and the morphological characterization of biotypes as described by Ulzurrun et al [8], a total of five C. bonariensis biotypes were selected for subsequent experiments (Table 1). However, it was not possible to select susceptible biotypes of C. bonariensis from this collection.…”

Addition à la flore vasculaire du Puy-de-Dôme : Erigeron blakei Cabrera (Asteraceae, subtrib. Conyzinae).

“…Nom français : Vergerette de Blake ; espèce dédiée à Sydney Fay Blake (1892Blake ( -1959, botaniste taxonomiste nord-américain qui étudia notamment les astéracées sud-américaines (Blake 1960). En termes phylogénétiques, E. blakei se montre proche de E. sumatrensis, tous deux distants de E. bonariensis et plus encore de E. canadensis (Nesom 2008a ;Diez de Ulzurrun et al 2018). Des hybridations entre E. blakei et E. sumatrensis (2n = 54), ainsi qu'avec E. bonariensis (2n = 54) seraient-elles possibles ?…”