Titre :
|
An isozyme study in Norway Spruce on the effect on population genetic parameters of juvenile selection followed-up by clonal propagation by cuttings
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Auteurs :
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H. Wellendorf ;
E. Skov
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Type de document :
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article/chapitre/communication
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Année de publication :
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1994
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ISBN/ISSN/EAN :
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87-7432-401-2
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Format :
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35 p.
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Note générale :
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Cette partie est contenue dans le document D 4543
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Langues:
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= Anglais
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Catégories :
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Biologie végétale - Génétique
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Mots-clés:
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DANEMARK
;
PICEA ABIES
;
AMELIORATION GENETIQUE
;
GENETIQUE DE POPULATION
;
SELECTION
;
MULTIPLICATION VEGETATIVE
;
CLONE
;
BOUTURE
|
Résumé :
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The procedure of juvenile selection in the nursery followed-up by clonal propagation by cuttings is described as an integrated part of the Danish Norway spruce breeding program in the 1970's and 1980's. Current demands for genetic diversity in productive populations are stated. The aim of the investigation was to monitor, it basic population genetic parameters were influenced by the initial juvenile selection of sets of 75-85 clones. The applied tool for detecting changes was a set of 12 isozyme systems with a total of 13 polymorphic loci supposed to be neutral. The methodology of running and analyzing these isozyme systems on starch gels is described in some details. Applied population genetic parameters estimated at age 10 in the base population and in the population of cutting propagated clones were allelic distributions, genetic diversity, genotypic distributions and multilocus estimates of Wright's fixation index. Allelic frequencies were influenced in two of the 13 loci, whereas genetic diversity was not. The fixation index moved from near zero for the base population to + 0.21 in the population of clones. This relative high level is outside the normal interval of an earlier range-wide investigation of Norway spruce at a comparable age. By selecting sets of 85 clones, no detectable loss of genetic diversity seems to occur. The recorded changes in allele distributions and the fixation index might be due to sampling error, direct selection pressure or linkage disequilibrium between markers and quantitative trait loci behind juvenile height growth. Future investigations on associations between individual clone parameters - e.g. heterozygosity - and fitness and other performance characters may shed light on the mechanisms behind the observed changes. Postulated functional isozyme systems may be included.
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Source :
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Forest tree improvement - Arboretum Horsholm Danemark, vol n°25
|