A concept for seed orchards based on isoenzyme gene markers

Advanced silvicultural methods in Thuringia as well as the necessity to preserve the generic resources of endangered tree species have led to the goal of establishing seed orchards of silver fir (Abies alba Mill.). In order to combine several economic and genetic features in constructing these seed orchards, the clones were chosen using a multistep procedure accompanied by genetic surveys at isoenzyme loci. Of the initial material consisting of 26 indigenous stands, 500 plus-trees were selected according to their vitality and growth. Based on several sampling strategies where the clone collections were stratified according to the level of gene diversity, occurrence of rare alleles and degree of homozygosity, 130 clones were finally chosen from the plus-tree collection. These clones are assumed to include all essential features attributed to a seed orchard which should produce vital and improved seed crop and preserve the gene pool of silver fir. (C) 2000 Elsevier Science B.V. All rights reserved.