Journal of Heredity Advance Access originally published online on October 16, 2008
Journal of Heredity 2009 100(1):66-75; doi:10.1093/jhered/esn084
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Original Articles |
Low Level of Pollen-Mediated Gene Flow from Cultivated to Wild Grapevine: Consequences for the Evolution of the Endangered Subspecies Vitis vinifera L. subsp. silvestris
From the Institut National de la Recherche Agronomique, UMR 1097, Diversité et Adaptation des plantes Equipe "Diversité, Génétique et génomique Vigne," 2, Place Viala, 34060 Montpellier, France (Di Vecchi-Staraz, Laucou, Bruno, Lacombe, Bourse, and This); the Institut National de la Recherche Agronomique, UMR 1202, BioGEco, Biodiversité, gènes et Communautés, Université Bordeaux I, 69 route d'Arcachon, 33612 Cestas cedex, France (Gerber); and the Dipartimento di Scienze, Tecnologie e Mercati della Vite e del Vino, Università degli Studi di Verona, Villa Lebrecht, Via della Pieve, 70, 37029 San Floriano (VR), Italy (Di Vecchi-Staraz, and Boselli)
Address correspondence to P. This at the address above, or e-mail: this{at}supagro.inra.fr.
A parentage and a paternity-based approach were tested for estimation of pollen-mediated gene flow in wild grapevine (Vitis vinifera L. subsp. silvestris), a wind-pollinated species occurring in Mediterranean Europe and southwestern Asia. For this purpose, 305 seedlings collected in 2 years at 2 locations in France from 4 wild female individuals and 417 wild individuals prospected from France and Italy were analyzed using 20 highly polymorphic microsatellite loci. Their profiles were compared with a database consisting of 3203 accessions from the Institut National de la Recherche Agronomique Vassal collection including cultivars, rootstocks, interspecific hybrids, and other wild individuals. Paternity was assigned for 202 (66.2%) of the 305 seedlings, confirming the feasibility of the method. Most of the fertilizing pollen could be assigned to wild males growing nearby. Estimates of pollen immigration from the cultivated compartment (i.e., the totality of cultivars) ranged from 4.2% to 26% from nearby vineyards and from hidden pollinators such as cultivars and rootstocks that had escaped from farms. In an open landscape, the pollen flow was correlated to the distance between individuals, the main pollinator being the closest wild male (accounting for 51.4–86.2% of the pollen flow). In a closed landscape, more complex pollination occurred. Analysis of the parentage of the 417 wild individuals also revealed relationships between nearby wild individuals, but in the case of 12 individuals (3%), analysis revealed pollen immigration from vineyards, confirming the fitness of the hybrid seedlings. These pollen fluxes may have a significant effect on the evolution of wild populations: on the one hand, the low level of pollen-mediated gene flow from cultivated to wild grapevine could contribute to a risk of extinction of the wild compartment (i.e., the totality of the wild individuals). On the other hand, pollen dispersal within the wild populations may induce inbreeding depression of wild grapevines.
Key Words: paternity analysis • pollen dispersal • rootstock • seedling • transgenic plant • true-to-type
Corresponding Editor: Brian Murray
Received December 12, 2007
Revised July 11, 2008
Accepted September 5, 2008