1. SSR-based analysis of clonality, spatial genetic structure and introgression from the Lombardy poplar into a natural population of Populus nigra L. along the Loire River
- Author
-
Marc Villar, Catherine Bastien, Romain Valade, Sophie Arnaud-Haond, José-Luis Almeida, Nicolas Chenault, Arnaud Dowkiw, Mary Juteau, Unité de recherche Amélioration, Génétique et Physiologie Forestières (AGPF), Institut National de la Recherche Agronomique (INRA), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Génétique et Biomasse Forestières Orléans (GBFOR), The authors thank Catherine Pasquier from INRA Orleans, UR 0272 USS, for crucial field and laboratory assistance with the geographic information systems, Vanina Guerin and Veronique Jorge from INRA Orleans, UR 0588 UAGPF, for their help and advice on SSR genotyping, Patrick Poursat and the INRA Orleans UE 0995 GBFOR for assistance with fieldwork, and special thanks to Frederic Millier for the increment core sample collection and preparation, Francoise Laurans and Alain Moreau from INRA Orleans, UR 0588 UAGPF, for their meticulous help with the core analysis, Jean Dufour from INRA Orleans, UR 0588 UAGPF, and Michel Chantereau, Administrator of the Saint-Mesmin French Natural Reserve, for floristic inventories, and and two anonymous reviewers who made very useful comments about this work and the resulting paper. Nicolas Chenault was supported by a PhD grant co-financed by INRA and Conseil Regional de la Region Centre, France. This study was carried out with financial support from INRA (programme ECOGER, projet INTERPOPGER).
- Subjects
genetics and heredity ,0106 biological sciences ,Introgression ,Vegetative reproduction ,clonality ,Spatial genetic structure ,Horticulture ,Biology ,Spatial distribution ,010603 evolutionary biology ,01 natural sciences ,03 medical and health sciences ,Clonal growth form ,Botany ,Genetics ,[SDV.BV]Life Sciences [q-bio]/Vegetal Biology ,Molecular Biology ,030304 developmental biology ,Hybrid ,Lombardy poplar ,0303 health sciences ,Forestry ,15. Life on land ,biology.organism_classification ,Natural population growth ,Seedling ,Genetic structure ,Species richness ,Populus nigra ,Clonality - Abstract
International audience; A scarcity of favourable habitats and introgression from exotic cultivars are two major threats to black poplars (Populus nigra L.) in Europe. Natural vegetative propagation contributes to maintenance of the species in areas where seedling recruitment is limited. Exhaustive sampling of all mature trees in a natural P. nigra stand (413 individuals at recorded positions), genotyping at 11 SSR loci, and a standardized analysis framework resulted in a precise description of clonality in terms of (a) frequency, (b) spatial growth form, and (c) impacts on the overall spatial genetic structure (SGS). The high proportion of replicated genotypes detected resulted in a genotypic richness (R) of 0.47. Up to 18 ramets were found per multilocus lineage (MLL), but 95% of MLLs contained fewer than five ramets (Pareto index β = 1.07). No significant difference in vegetative propagation potential was found between genders. Uneven spatial distribution of ramets, with clustering of clonal ramets (aggregation index A c = 0.62) and near-zero intermingling between MLLs (clonal dominance index D c = 0.99), resulted in a ‘phalanx’ clonal growth form, explaining most of the SGS observed over short distances (0–20 m, Sp = 0.0324). Although they did not exhibit the typical columnar shape of the Lombardy poplar (P. nigra var. italica), five trees were found to be probable F1 hybrids of this old and widely distributed cultivar.
- Published
- 2011