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Auteur Joan Cottrell
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Forest Research, Northern Research Station, Roslin, Midlothian EH25 9SY, UK
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Documents disponibles écrits par cet auteur (2)



Hybridization between Quercus robur and Q. petraea in a mixed oak stand in Denmark / J. Jensen in Annals of Forest Science, Vol 66 n° 7 (October - November 2009)
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Titre : Hybridization between Quercus robur and Q. petraea in a mixed oak stand in Denmark Titre original : Hybridation entre Quercus robur et Q. petraea dans un peuplement mélangé de chênes au Danemark Type de document : Article/Communication Auteurs : J. Jensen, Auteur ; Anders Larsen, Auteur ; Lene R. Nielsen, Auteur ; Joan Cottrell, Auteur Année de publication : 2009 Article en page(s) : n° 706 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] Danemark
[Termes IGN] diversité génétique
[Termes IGN] hybridation naturelle (végétation)
[Termes IGN] peuplement mélangé
[Termes IGN] Quercus pedunculata
[Termes IGN] Quercus sessiliflora
[Vedettes matières IGN] SylvicultureRésumé : (Editeur) Hybridization and mating pattern between Quercus robur and Q. petraea was studied in a 5.8 ha mixed forest stand in Jutland, Denmark which comprises in total 135 Quercus robur and 230 Q. petraea trees. Classification of the oak trees into species was performed using canonical discriminant analysis of a range of leaf morphological traits. Adult trees (365) and offspring (582) were genotyped with eight microsatellite markers. Seedlings were sampled in 2003 and acorns were collected in 2004. Mating patterns of Q. robur and Q. petraea are expected to be different in the northern range of the distribution area and a larger hybridization rate is expected. It is further expected, that pollination from outside sources will be relatively less in small fragmented forest management systems compared to large scale oak forest. The conclusions should be verified through repeated year to year analysis of the mating pattern. Phenological studies revealed that there was no difference in flowering time between species. Data for the adult trees revealed no significant departures from Hardy-Weinberg proportions and there was weak, but significant spatial genetic structure, which supports the idea that the stand is of natural origin. Spatial genetic structure in the first distance class is stronger for Q. petraea. The genetic composition of the offspring was remarkably consistent from year to year. Paternity analysis revealed that, on average, 85% pollination came from fathers within the stand. The direction of the pollen flow varied from year to year. Inter-specific hybridization was high and ranged from 15–17% and from 48–55% for Q. petraea and Q. robur mothers respectively. Paternity analysis revealed that the population was basically outcrossing and only 3.7% of the analysed progeny were the product of selfing. Over the two years of study, approximately 200 trees contributed to the paternity of the next generations.
The study confirms earlier studies with a greater tendency for Q. robur mothers to produce hybrid seeds than Q. petraea mothers. The rate of hybridization is higher in this Danish stand than in comparable studies elsewhere in Europe. Gene flow from outside sources are relatively low.Numéro de notice : A2009-627 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1051/forest/2009058 Date de publication en ligne : 02/10/2009 En ligne : https://www.afs-journal.org/articles/forest/full_html/2009/07/f08308/f08308.html Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=72830
in Annals of Forest Science > Vol 66 n° 7 (October - November 2009) . - n° 706[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité IFN-001-P000668 PER Revue Nogent-sur-Vernisson Salle périodiques Exclu du prêt Leaf morphological differentiation between Quercus robur and Quercus petraea is stable across western European mixed oak stands / Antoine Kremer in Annals of Forest Science, vol 59 n° 7 (novembre 2002)
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Titre : Leaf morphological differentiation between Quercus robur and Quercus petraea is stable across western European mixed oak stands Type de document : Article/Communication Auteurs : Antoine Kremer, Auteur ; Jean-Luc Dupouey, Auteur ; J. Douglas Deans, Auteur ; Joan Cottrell, Auteur ; Ulrike Csaikl, Auteur ; Reiner Finkeldey, Auteur ; Santiago Espinel, Auteur ; et al., Auteur Année de publication : 2002 Article en page(s) : pp 777 - 787 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Végétation
[Termes IGN] Europe occidentale
[Termes IGN] feuille (végétation)
[Termes IGN] peuplement forestier
[Termes IGN] Quercus pedunculata
[Termes IGN] Quercus sessiliflora
[Termes IGN] taxinomieMots-clés libres : morphology leaf Quercus robur Quercus petraea taxonomy Résumé : (auteur) Leaf morphology was assessed in nine mixed oak stands (Quercus petraea and Q. robur) located in eight European countries. Exhaustive sampling was used in an area of each stand where the two species coexisted in approximately equal proportions (about 170 trees/species/ stand). Fourteen leaf characters were assessed on each of 5 to10 leaves collected from the upper part of each tree. Three multivariate statistical techniques (CDA, canonical discriminant analysis; PCA, principal component analysis; MCA, multiple correspondence analysis) were used in two different ways: first on the total set of leaves over all stands (global analysis) and second, separately within each stand (local analysis). There was a general agreement of the results among the statistical methods used and between the analyses conducted (global and local). The first synthetic variable derived by each multivariate analysis exhibited a clear and sharp bimodal distribution, with overlapping in the central part. The two modes were interpreted as the two species, and the overlapping region was interpreted as an area where the within-species variations were superimposed. There was no discontinuity in the distribution or no visible evidence of a third mode which would have indicated the existence of a third population composed of trees with intermediate morphologies. Based on petiole length and number of intercalary veins, an “easy to use” discriminant function applicable to a major part of the natural distribution of the species was constructed. Validation on an independent set of trees provided a 98% rate of correct identification. The results were interpreted in the light of earlier reports about extensive hybridization occurring in mixed oak stands. Maternal effects on morphological characters, as well as a lower frequency or fitness of hybrids in comparison with parent species could explain the maintenance of two modes, which might be composed of either pure species or pure species and introgressed forms. Numéro de notice : A2002-055 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article DOI : 10.1051/forest:2002065 En ligne : http://dx.doi.org/10.1051/forest:2002065 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81013
in Annals of Forest Science > vol 59 n° 7 (novembre 2002) . - pp 777 - 787[article]Documents numériques
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