Phylogeography of the invasive weed Hypochaeris radicata (Asteraceae): from Moroccan origin to worldwide introduced populations

Abstract

In an attempt to delineate the area of origin and migratory expansion of the highly successful invasive weedy species Hypochaeris radicata, we analysed amplified fragment length polymorphisms from samples taken from 44 populations. Population sampling focused on the central and western Mediterranean area, but also included sites from Northern Spain, Western and Central Europe, Southeast Asia and South America. The six primer combinations applied to 213 individuals generated a total of 517 fragments of which 513 (99.2%) were polymorphic. The neighbour-joining tree presented five clusters and these divisions were supported by the results of Bayesian analyses: plants in the Moroccan, Betic Sierras (Southern Spain), and central Mediterranean clusters are all heterocarpic. The north and central Spanish, southwestern Sierra Morena, and Central European, Asian and South American cluster contain both heterocarpic (southwestern Sierra Morena) and homocarpic populations (all other populations). The Doñana cluster includes two homocarpic populations. Analyses of fragment parameters indicate that the oldest populations of H. radicata are located in Morocco and that the species expanded from this area in the Late Quaternary via at least three migratory routes, the earliest of which seems to have been to the southwestern Iberian Peninsula, with subsequent colonizations to the central Mediterranean area and the Betic Sierras. Homocarpic populations originated in the southwestern Iberian Peninsula and subsequently spread across north and central Spain, Central Europe and worldwide, where they became a highly successful weed.

Genetic structure and population diversity of eleven edible herbs of Eastern Crete

“…A few studies have focused on some of the genera included in the present study using molecular markers [7, 8], however samples from Greece were limited. It is generally accepted that information regarding the mode of reproduction (self-/cross-pollination), the life cycle (annual/perennial), the genetic structure and diversity of a plant species is essential for its conservation [9–11].…”

“…In general, annual species with high germination percentage, fast growth and reproduction, show low within and high among population diversity [17]. Honnay et al [18] and Ortiz et al [8] refer to H. radicata as a self-pollinating, but primarily is considered as a cross-pollinating species. They proposed that the species in its ancestral hobs (North Africa) behaves as a cross-pollinator and that some individuals appear as self-pollinators.…”

Phylogeny and genetic structure of Erophaca (Leguminosae), a East–West Mediterranean disjunct genus from the Tertiary

“…This diversity can be due to the ancestral nature of populations (in the case of Erophaca, they present the largest numbers of private and rare fragments which tend to accumulate over time; Stehlik et al, 2002;Schönswetter and Tribsch, 2005) or, alternatively, be a by-product of larger population sizes during Pleistocene climatic fluctuations. As regards regional genetic differentiation at each side of the Guadalquivir River Valley, even though this has been demonstrated in other taxa (e.g., Hypochaeris radicata; Ortiz et al, 2008), in the case of E. baetica the role of this barrier impeding gene flow should be considered less important (compared to the Strait of Gibraltar). According to Mantel tests, southernmost Iberian populations (i.e., on the Betic Sierras) were genetically similar to the African ancestral pool, whereas those from the Iberian Massif appeared relatively impoverished and poorly structured (suggesting they are relatively recent).…”

“…The AFLP (Amplified Fragment Length Polymorphism) technique is appropriate for phylogeographic studies because it allows genotyping of large numbers of loci in many different individuals, and hence the elucidation of genetic population structures and recent phylogenies (Weising et al, 2005). Phylogeographic studies using AFLP have been successfully carried out of legume taxa in Europe and America (e.g., Anthyllis montana; Kropf et al, 2002;Astragalus ampullarioides;Breinholt et al, 2009; Astragalus cremnophylax; Travis et al, 1996;Oxytropis campestris;Chung et al, 2004), as well as in Mediterranean species of diverse plant groups (Ortiz et al, 2008;Piñeiro et al, 2007;Terrab et al, 2008).…”

Distributions of vascular plants in the Czech Republic

“…49) Hypochaeris radicata is a species both of man-made and natural habitats and currently is distributed across most of the world. Based on molecular data, it originated in Morocco and during the Quaternary period it spread into the Mediterranean area (Ortiz et al 2008). Its further spread to other parts of Europe, Asia and Africa was associated with human activities; more recently it has been introduced also into the Americas.…”