title: Metapopulation structure and fine-scaled genetic structuring in crop-wild hybrid weed beets.
abstract: This study explores the microspatial and temporal genetic variation in crop-wild hybrid weed beets that emerged from the seed bank in a cultivated field surveyed over two successive years. We demonstrate the occurrence of demes highly genetically differentiated, kin-structured, characterized by moderate effective population sizes, differing in propensity for selfing, and arising from nonrandom genetic subsets of the seed bank. Only one deme identified in the first survey year significantly contributed to the weed beets that emerged in the second year. Spatial structuring appears to be primarily due to gravity seed dispersal and limited pollen flow among weed beet demes. Within each genetic cluster identified by Bayesian assignments and multivariate analyses, F(IS) estimates and level of biparental inbreeding--revealed by progeny analyses--dropped to non-significant values. This suggests that random mating occurs at the scale of genetically distinct demes over a very short scale. Our results highlight the need to carefully depict genetic discontinuities in weed species, when attempting to describe their local genetic neighborhoods within which genetic drift and selective processes occur.
authors: Laboratoire de Génétique et Évolution des Populations Végétales, FRE CNRS 3268, Bâtiment SN2, Université des Sciences et Technologies de Lille-Lille 1, Villeneuve d'Ascq cedex, France. jean-francois.arnaud@univ-lille1.fr
authors: J-F
authors: JF
authors: Arnaud
authors: J
authors: J
authors: Cuguen
authors: S
authors: S
authors: Fénart
mesh_terms: D001499:Bayes Theorem; D027461:Beta vulgaris / Q000235:genetics* / Q000502:physiology; D040961:Genetic Drift; D014644:Genetic Variation; D007178:Inbreeding; D018895:Microsatellite Repeats; D008957:Models, Genetic; D015999:Multivariate Analysis; D057685:Plant Weeds / Q000235:genetics*; D054817:Pollination / Q000235:genetics; D025341:Principal Component Analysis; D012641:Selection, Genetic; D057945:Self-Fertilization / Q000235:genetics