title: Taxonomic, spatial and adaptive genetic variation of Beta section Beta.
abstract: CONCLUSIONS
  The genetic variation of Beta section Beta is structured into four taxonomic and spatial clusters. There are significant associations between molecular markers and environmental variables.
  We investigated the genetic diversity of Beta section Beta, which includes the wild and cultivated relatives of the sugar beet. The taxa included in the study were: Beta vulgaris subsp. maritima, B. vulgaris subsp. adanensis, B. macrocarpa, B. patula and B. vulgaris subsp. vulgaris (garden beet, leaf beet and swiss chards). We collected 1264 accessions originating from the entire distribution area of these taxa and genotyped them for 4436 DArT markers (DArTs). We showed that the genetic variation of these accessions is structured into four taxonomic and spatial clusters: (1) samples of Beta macrocarpa, (2) samples of Beta vulgaris subsp. adanensis, (3) Mediterranean and Asian samples and (4) Atlantic and Northern European samples. These last two clusters were mainly composed of samples of Beta vulgaris subsp. maritima. We investigated in deeper detail the genetic structure of B. vulgaris subsp. maritima, which constituted the majority (80%) of the wild samples. This subspecies exhibited a clinal genetic variation from South-East to North-West. We detected some markers significantly associated to environmental variables in B. vulgaris subsp. maritima. These associations are interpreted as results of natural selection. The variable most often involved in the associations was annual mean temperature. Therefore, these markers can be useful for the development of frost-tolerant winter beets and drought-tolerant rain-fed beets.
authors.affiliation: Laboratoire Biogeographie et écologie des vertébrés, CEFE UMR 5175, CNRS - Universite de Montpellier - Universite Paul-Valery Montpellier - EPHE, 34293, Montpellier Cedex 5, France. marco.andrello@gmail.com.
authors.forename: Marco
authors.initials: M
authors.lastname: Andrello
authors.affiliation: Florimond Desprez, 59242, Cappelle En Pévèle, France.
authors.forename: Karine
authors.initials: K
authors.lastname: Henry
authors.affiliation: Florimond Desprez, 59242, Cappelle En Pévèle, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Devaux
authors.affiliation: Florimond Desprez, 59242, Cappelle En Pévèle, France.
authors.forename: Bruno
authors.initials: B
authors.lastname: Desprez
authors.affiliation: Laboratoire Biogeographie et écologie des vertébrés, CEFE UMR 5175, CNRS - Universite de Montpellier - Universite Paul-Valery Montpellier - EPHE, 34293, Montpellier Cedex 5, France.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Manel
mesh_terms: D000220:Adaptation, Biological / Q000235:genetics*; D001499:Bayes Theorem; D027461:Beta vulgaris / Q000235:genetics*; D019663:Chenopodiaceae / Q000235:genetics; D016000:Cluster Analysis; D018556:Crops, Agricultural / Q000235:genetics; D018744:DNA, Plant / Q000235:genetics; D059647:Gene-Environment Interaction; D005819:Genetic Markers; D014644:Genetic Variation; D005828:Genetics, Population; D005838:Genotype; D016014:Linear Models; D008957:Models, Genetic; D025341:Principal Component Analysis
chemical_list: D018744:DNA, Plant; D005819:Genetic Markers