Browsing by Author "Gerber, Sophie"
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- Genetic variation, mating patterns and gene flow in a Pinus pinaster Aiton clonal seed orchardPublication . Fernandes, Lúcia; Rocheta, Margarida; Cordeiro, Jorge; Pereira, Sandra; Gerber, Sophie; Oliveira, Maria M.; Ribeiro, M.M.A.Relatedness among parents, variation in clonal fertility and background pollination deviate the realized genetic gain and the gene diversity of open pollinated seed orchard from expectation, in particular in wind pollinated species such as Pinus pinaster Aiton. • This work investigates the genetic variation, the mating system and the pollen contamination in a P. pinaster clonal seed orchard (CSO), by screening the 60 clones from the CSO and the seeds collected from 21 mother-trees with three nuclear microsatellites. • The expected diversity was similar, but the observed heterozygosity decreased 20% in the progenies compared with the parental trees. The outcrossing rate was 90.1%, the biparental inbreeding 21.7% computed through a multilocus approach, and the observed selfing 3.9%. The observed gene flow from outside the CSO was 52.4%. • From the results we concluded that the observed gene flow and the biparental inbreeding were high, and care should be taken in the implementation and management of future CSO, in particular clones should be checked for relatedness and the ramet number could be directly proportional to their breeding value.
- Origin identification of maritime pine stands in France using chloroplast simple-sequence repeatsPublication . Ribeiro, M.M.A.; Le Provost, Grégoire; Gerber, Sophie; Vendramin, Giovanni Giuseppe; Anzidei, Maria; Decroocq, Stéphane; Marpeau, Anne; Mariette, Stéphanie; Plomion, ChristopheMaritime pine seed-lots from north-western Iberian regions (Portugal and Galicia) were introduced in the 1950s to the southwest of France (Aquitaine region), and the stands they formed suffered considerable frost damage. In the mid 1980s, a biochemical test was developed to test the putative origin of adult stands in Aquitaine, before seeds could be distributed for commercial purposes in France. In this paper, we describe a new test employing chloroplast simple-sequence repeats (cpSSRs) to facilitate identification of stand origin based on randomisation tests. The origin of five stands of unknown origin was determined with both the cpSSR and biochemical (terpene profile analysis) tests. The results from the two tests were concordant, but the DNA-based test gave faster and more accurate results. Use of this test should help when determining the origin of maritime pine stands in the Aquitaine region of France.
- What can nuclear microsatellites tell us about maritime pine genetic resources conservation and provenance certification strategies?Publication . Dérory, Jérémy; Mariette, Stéphanie; González-Martínez, Santiago; Chagné, David; Madur, Delphine; Gerber, Sophie; Brach, Jean; Persyn, François; Ribeiro, M.M.A.; Plomion, ChristopheMaritime pine (Pinus pinaster Ait.) is the first conifer used for reforestation in France and now covers 2.4 million ha of the Iberian Peninsula. In order to preserve the genetic resources of this economically and ecologically important species prior knowledge of the distribution of genetic diversity is needed. In this paper, a genetic diversity study was performed using nuclear simple sequence repeats (SSRs or microsatellites). Classical parameters of diversity (allelic richness and heterozygosity) and differentiation were estimated for 47 populations of P. pinaster. Most of the populations (40) were collected in France, six populations were also collected in the Iberian Peninsula and one Moroccan population was also included in the study. The population genetic parameters indicated that some populations should be a focus of conservation efforts (higher level of diversity, higher allelic richness and presence of rare alleles). A diagnostic test for sample origin was developed to distinguish Corsican from Landes populations.