HOW REPRESENTATIVE ARE PROVENANCES FROM A GENETIC ASPECT - AN EXAMPLEFROM A ABIES-ALBA PROVENANCE TRIAL

Using the provenance ''Tiengen'' from the South-German Abies alba prov enance trial we attempted to evaluate how representative provenance co llections are from a genetic standpoint. The provenances ''Tiengen I'' and ''Tiengen II'' represents the same region but the seed was collec ted in different years. Using Isoezyme analysis the genetic structures at. 14 polymorphic gene loci were determined for 555 individuals incl uded in the provenance trial and for 100 older fir trees still standin g in the same region (''Tiengen A''); various parameters of generic va riation were computed for this data. The results show that the genetic multiplicity of the collective of older trees (''Tiengen A'') was sli ghtly higher than in the samples of the field trial (''Tiengen I'' and ''Tiengen II''), whereby the latter did not always have the same rare alleles. The collectives in the trial had higher values of diversity and heterozygosity than the collective of older trees from the region of seed collection. The genetic distance is least among ''Tiengen A'' and ''Tiengen I'' and highest among ''Tiengen A'' and ''Tiengen II''. The genetic differentiation among all collectives is statistically sig nificant at 9 gene loci. On an average over all loci ''Tiengen I'' was the least, ''Tiengen II'' the most differentiated. Thus, ''Tiengen I' ' appeared to be the most representative for this region. Possible cau ses for these findings can lie in the reproductive system, the mode of seed collection, nursery processes, specific microgeographic genetic variation of Abies alba. These findings are discussed in relation to t he interpretation of various phenotypic parameters in field trials. Th e possibility of using genetic markers in the planning and establishme nt phase of provenance trials is mentioned.