Original scientific paper
https://doi.org/10.15177/seefor.18-09
Genetic Diversity of Pedunculate Oak (Quercus robur L.) in Clonal Seed Orchards in Croatia, Assessed by Nuclear and Chloroplast Microsatellites
Ida Katičić Bogdan
; University of Zagreb, Faculty of Forestry, Department of Forest Genetics, Dendrology and Botany, Svetošimunska 25, HR-10000 Zagreb, Croatia
Davorin Kajba
; University of Zagreb, Faculty of Forestry, Department of Forest Genetics, Dendrology and Botany, Svetošimunska 25, HR-10000 Zagreb, Croatia
Zlatko Šatović
; University of Zagreb, Faculty of Agriculture, Department of Seed Science and Technology, Svetošimunska 25, HR-10000 Zagreb, Croatia
Silvio Schüler
; Austrian Research Centre for Forests - BFW, Department of Forest Growth and Silviculture, Seckendorff-Gudent-Weg 8, A-1131 Vienna, Austria
Saša Bogdan
; University of Zagreb, Faculty of Forestry, Department of Forest Genetics, Dendrology and Botany, Svetošimunska 25, HR-10000 Zagreb, Croatia
Abstract
Background and Purpose: Natural stands of pedunculate oak in Croatia have been delineated in seed areas, zones and regions. The current bylaw recommends that the transfer of reproductive material remains limited within zones, but that it is permitted within areas. Clonal seed orchards (CSOs) of pedunculate oak were established to increase genetic quality of seed and to acquire a more regular seed yield than in natural stands. In total 150 plus trees were selected within three seed regions. The selection included a number of favourable traits of tree size and stem quality. Three CSOs were planted with grafted plus-trees. We aimed to establish whether these orchards encompass enough genetic diversity to potentially produce genetically improved and sufficiently diverse reproductive material. We also wanted to assess neutral genetic differentiation between these orchards and compare it with the genetic diversity obtained from chloroplast DNA markers, depicting conserved lineages from recolonization routes. We wanted to investigate spatial genetic structure in the area of our research and provide additional information on the transfer of forest reproductive material.
Materials and Methods: Leaves were collected from all clones in the CSOs. Total genomic DNA was extracted and clones were analysed with eight nuclear and ten chloroplast microsatellite markers. Spatial autocorrelation analysis was performed with nuclear microsatellite data and original plus trees’ coordinates, for each CSO separately, to determine whether shared favourable traits among the selected plus trees in smaller distances are the results of relatedness, which the sampling strategy tried to avoid.
Results: We found 28 chloroplast haplotypes belonging to four maternal lineages, and significant differentiation between CSOs, indicating origin from different refuges. Nuclear microsatellites’ diversity in the CSOs is quite high and comparable to diversity found within a recent study of Croatian natural populations. Nuclear microsatellites did not show genetic differentiation between CSOs, i.e. between the seed regions and seed zones they represent. No genetic differentiation was found with nuclear microsatellites among haplotypic lineages. We found no genetic structure within the analysed regions.
Conclusions: Lack of differentiation between CSOs found with nuclear microsatellites confirms the permission for transfer of reproductive material between zones within the seed area 1 - Lowland Forests. If original differentiation between chloroplast haplotypic lineages was present after recolonization, it was erased by subsequent gene flow. Lack of genetic structure, with nuclear microsatellites within regions indicates successful sampling strategy.
Keywords
plus trees; clonal seed orchards; seed regions; genetic differentiation; haplotypic lineages; spatial autocorrelation analysis
Hrčak ID:
203546
URI
Publication date:
30.6.2018.
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