Population structure in chicory (Cichorium intybus): A successful U.S. weed since the American revolutionary war

Abstract

Plant invasions are recognized as major drivers of ecosystem change, yet the precise cause of these invasions remains unknown for many species. Frequency and modes of introductions during the first, transport and colonization, stages of the invasion process as well as phenotypic changes due to plasticity or changing genetic diversity and adaptation during later establishment and expansion stages can all influence the “success” of invasion. Here, we examine some of these factors in, and the origin of, a very successful weed, Cichorium intybus (chicory) which was introduced to North America in the 18th century and which now can be found in all 48 continental U.S. states and much of Canada. We genotyped a Eurasian collection of 11 chicory cultivars, nine native populations and a North American collection of 20 introduced wild populations which span the species range (592 individuals in total). To detect the geographic sources of North American chicory populations and to assess the genetic diversity among cultivars, native, and introduced populations, we used both a sequenced cpDNA region and 12 nuclear simple sequence repeat (SSR), microsatellite loci. Four cpDNA haplotypes were identified and revealed clear geographic subdivisions in the chicory native range and an interspecific hybrid origin of Radicchio group. Nuclear data suggested that domesticated lines deliberately introduced to North America were major contributors to extant weedy populations, although unintended sources such as seed contaminants likely also played important roles. The high private allelic richness and novel genetic groups were detected in some introduced populations, suggesting the potential for local adaptation in natural sites such as deserts and nature reserves. Our findings suggest that the current populations of weedy U.S. chicory have evolved primarily from several sources of domesticated and weedy ancestors and subsequent admixture among escaped lineages.

Population genomics reveal multiple introductions and admixture of Sonchus oleraceus in Australia

“…Overall, our results suggest that introductions of S. oleraceus into (Závada et al, 2017), suggesting this is a mechanism for intercontinental introductions to Australia. Given the cosmopolitan distribution of S. oleraceus, we cannot exclude the possibility that there have been introductions from other continents (e.g.…”

“…Introductions from multiple geographical sources are not uncommon in Asteraceae with long seed dispersal mechanisms as observed in the yellow star‐thistle ( Centaurea solstitialis ) (Barker et al, 2017) and ragweed ( Artemisia artemisiifolia ) (van Boheemen et al, 2017). Sonchus oleraceus is a well‐known contaminant of seed crops (CABI, 2019), and weed seeds are commonly encountered in trading pathways due to human socioeconomic activities (Závada et al, 2017), suggesting this is a mechanism for intercontinental introductions to Australia. Given the cosmopolitan distribution of S. oleraceus , we cannot exclude the possibility that there have been introductions from other continents (e.g.…”

Population structure, seasonal genotypic differentiation, and clonal diversity of weedy dandelions in three Boston area populations (Taraxacum sp.)

“…The thermal cycler conditions for touchdown PCR as described in Zavada et al. ( 2017 ) were followed for the amplification of the microsatellite markers. Microsatellite amplicons were confirmed with 2% ethidium bromide agarose gels.…”

Characterization of Some Cichorium Taxa Grown under Mediterranean Climate Using Morphological Traits and Molecular Markers

“…The genetic identification and differentiation of a taxon are applied in various species such as Brassica [ 24 ], broccoli and cauliflower [ 25 ], lettuce and Jew’s mallow [ 26 ], and tomato [ 27 ]. In Cichorium , various molecular markers were applied [ 7 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 ]. Some of these markers have been used for genetic map construction [ 31 , 32 ], genetic variation [ 33 , 34 ], gene flow [ 35 ], population structure [ 37 ], and hybridization [ 36 ].…”