Brief communication. RAPD variation in a Norway spruce seedlot: consequences of somatic embryogenesis

Abstract

Norway spruce (Picea abies L. Karst) somatic embryos can be obtained from about 25% of the seedlings from a provenance. Random amplified polymorphic DNAs (RAPDs) were used to investigate if plant production by somatic embryogenesis significantly eroded the genetic diversity of a provenance as a consequence of selection. A sample of 124 seedlings from a natural Norway spruce population, split into two subpopulations, that is, embryogenic (E; n=31) and nonembryogenic (NE; n=93) individuals, generated 210 RAPD fragments, each assumed to correspond to a locus. Assuming random mating under Hardy-Weinberg equilibrium, allele frequencies and differentiation indexes were estimated. The mean differentiation index over all loci was included within the distribution of a hundred differentiation indexes calculated after 100 simulations by random sampling 31 and 93 individuals. Moreover, the distributions of allele frequencies of the amplified alleles over all loci were similar between the E and NE subpopulations, and the distribution of the E individuals in clusters based upon genetic similarity was at random. Thus it was concluded that the selective effects of the embryogenesis process in the embryogenic subpopulation were not significant and that the erosion of the genetic diversity is mainly determined by bottleneck effects.