No abstract

A total of sixty-five accessions from the Spanish region of Castilla y León including those authorized in the VQPRD areas were characterized for six SSR loci. All the samples but one unknown were identified by comparison to other databases. Thirty synonymous samples and three cases of homonymy were found out, confirming in most cases ampelographic expectations. Five unique genotypes belonging to local varieties in risk of extinction were detected. Several parameters were calculated to assess the usefulness of the chosen loci in this work. A dendrogram representing the genetic similarities among the accessions was constructed using the neighbor-joining method to investigate possible parentage relationships in the sample, and to explain them from an historical and cultural point of view.

Atlantic and Mediterranean populations of maritime pine are very different in quantitative and adaptative traits, even to be considered different subspecies. Different authors have suggested the existence of glacial refugia for this species both in Portugal and eastern Spain based on molecular markers and supported by pollen and fossil records. In addition, based on the existence of high levels of haplotypic variation in this region, the Castilian Plateau is suggested as a contact zone between Atlantic and Mediterranean gene pools of the species. This hypothesis is tested using Bayesian clustering methods and exclusion tests based on multilocus genotypes obtained by genotyping 13 populations with three highly polymorphic nuclear microsatellites. The results show that Castilian Plateau populations constitute a different gene pool by itself that can not be fully originated from the Mediterranean or the Atlantic gene pools, or from a mixture of both. Therefore, three different hypotheses have been considered as plausible causes to give rise to Castilian Plateau maritime pine populations: i) fast colonization of the region from one or more Mediterranean refugial areas, ii) existence of cryptic refugia for the species in the zone, and iii) introduction of exotic material by humans.Key words: Glacial refugia, population structure, nuclear microsatellites, Castilian Plateau, Iberian Peninsula, maritime pine. Resumen ¿Mezcla de orígenes, colonización desde un solo refugio glacial o persistencia del pino negral en la Meseta Castellana? Perspectivas utilizando marcadores microsatélites nuclearesLas poblaciones atlánticas y mediterráneas de Pinus pinaster en la Peninsula Ibérica son muy diferentes en cuanto a caracteres cuantitativos se refiere, llegando a considerarse dos subespecies diferentes. Diversos autores, basándose en marcadores moleculares y en registros polínicos y fósiles, sugieren la existencia de refugios glaciares para la especie en Portugal y en el este de España. Por otro lado, y debido a la elevada variación haplotípica encontrada en las poblaciones de pino negral de la Meseta Castellana, se ha sugerido que esta región pueda ser una zona de contacto entre los acervos gené-ticos Atlántico y Mediterráneo. Para comprobar esta hipótesis se han genotipado 13 poblaciones de la especie con tres marcadores microsatélites nucleares muy polimórficos, y se han utilizando métodos de agrupamiento Bayesianos y análisis de exclusión. Los resultados obtenidos muestran que las poblaciones de la Meseta Castellana constituyen un acervo genético singular y que su origen no proviene de los acervos Atlántico o Mediterráneo, ni de una mezcla entre ambos. Por tanto, se han considerado tres hipótesis diferentes como posibles causas que han dado origen a las poblaciones de pino negral de la Meseta Castellana: i) rápida colonización de la región a partir de uno o varios refugios glaciares del este peninsular, ii) existencia de refugios crípticos para la especie en la zona, e iii) introducción antrópica de material foráneo.

No abstract