Where do the rare alleles hide themselves In Scots pine populations?

Abstract

Climatic change fastens the evolutionary clock for long-lived forest tree populations. Already over a single generation trees face drastic change in the adaptive targets along with new abiotic stresses and pest invasions. Evolutionary, forest trees meet these challenges by accumulating genetic diversity reserves. Rare alleles and genotypes are one of the genetic diversity tools required for species evolution. The problem is that common commercial forest management practice may purge way the rare alleles out of the forests. We also do not really know which genepools accumulate rare alleles in Scots pine and other forest trees. Objective of our study was by the aid of DNA markers assess the effects of forest tending on loss of rare alleles in Scots pine stands. We genotyped 400 trees in a single artificially established stand of Scots pine prior to the pre-commercial thinning at 6 gene based and 6 genomic nSSR loci. Age of the trees was 20 years. We measured the diameter of the genotyped trees and assigned the trees to be eliminated by a simulated thinning based on the diameter value (thinnest trees were removed first). The results showed that up 30 percent thinning intensity no marked loss of rare alleles with frequency below 5% occurs. However, with high thinning intensities loss of rare alleles becomes significant. We conclude that intensive commercial forest management reduces rare allele frequencies. To retain rare alleles a network of conservation forests must be maintainedMiškų ir ekologijos fakultetasVytauto Didžiojo universitetasŽemės ūkio akademij