title: Spatial genetic structure in wild cardoon, the ancestor of cultivated globe artichoke: Limited gene flow, fragmentation and population history.
abstract: Nuclear and chloroplast markers and phenotypic characters were integrated to analyse the population genetic structure of wild cardoon, Cynara cardunculus var. sylvestris, the ancestor of cultivated globe artichoke, Cynara cardunculus var. scolymus on the island of Sardinia, Italy. The spatial scale ranged from a few metres to ∼200km. Wild cardoon appears to be genetically fragmented, with significant genetic divergence at various scales, indicating that gene flow is insufficient to counterbalance the effects of genetic drift or founder effects. Divergence between populations was higher for chloroplast (40%) than for nuclear markers (15%), suggesting that gene flow via seed was lower than via pollen. Two main genetic groups were detected; these correlated with differences in flowering time, capitula size, glossiness, and anthocyanin pigmentation. A complex population structure of wild cardoon emerged over small spatial scales, likely resulting from the interplay between gene dispersal, colonisation history and selective forces. Indeed, Sardinia appears to be a 'hybrid zone' of different gene pools. The island has unique diverse germplasm that has originated from hybridisation among different gene pools. The sampling of seeds from a few plants but from many sites is suggested as the best strategy to harvest the genetic diversity of wild cardoon.
authors.affiliation: Dipartimento di Agraria, Università degli Studi di Sassari, Via E. De Nicola, 07100 Sassari, Italy. Electronic address: dmrau@uniss.it.
authors.forename: D
authors.initials: D
authors.lastname: Rau
authors.affiliation: Dipartimento di Agraria, Università degli Studi di Sassari, Via E. De Nicola, 07100 Sassari, Italy; Centro per la Conservazione e Valorizzazione della Biodiversità Vegetale, Università degli Studi di Sassari, Surigheddu, 07040 Alghero, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Rodriguez
authors.affiliation: AGRIS Sardegna, Servizio per la Ricerca in Arboricoltura, Via Mameli 126/D, Cagliari, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Rapposelli
authors.affiliation: Dipartimento di Agraria, Università degli Studi di Sassari, Via E. De Nicola, 07100 Sassari, Italy.
authors.forename: M L
authors.initials: ML
authors.lastname: Murgia
authors.affiliation: Dipartimento di Scienze Agrarie, Alimentari ed Ambientali (D3A), Università Politecnica delle Marche (UNIVPM), Via Brecce Bianche, 60131 Ancona, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Papa
authors.affiliation: Bioversity International (Honorary Research Fellow), Via dei Tre Denari, 472/a, 00054 Maccarese, Fiumicino, Italy.
authors.forename: A H D
authors.initials: AH
authors.lastname: Brown
authors.affiliation: Dipartimento di Agraria, Università degli Studi di Sassari, Via E. De Nicola, 07100 Sassari, Italy; Centro per la Conservazione e Valorizzazione della Biodiversità Vegetale, Università degli Studi di Sassari, Surigheddu, 07040 Alghero, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Attene
mesh_terms: D031942:Cynara / Q000235:genetics*; D018742:DNA, Chloroplast / Q000235:genetics*; D051456:Gene Flow; D007178:Inbreeding; D007558:Italy; D018895:Microsatellite Repeats; D010641:Phenotype; D058974:Phylogeography; D011110:Polymorphism, Genetic
chemical_list: D018742:DNA, Chloroplast
keywords: Colonisation history; Crop wild relatives; Cynara cardunculs var. sylvestris; Domestication; Fragmentation; Spatial genetic structure