ALLOZYME FREQUENCY-DISTRIBUTIONS IN 5 EUROPEAN POPULATIONS OF BLACK PINE (PINUS-NIGRA ARNOLD) .1. ESTIMATION OF GENETIC-VARIATION WITHIN AND AMONG POPULATIONS .2. CONTRIBUTION OF ISOZYME ANALYSIS TO THE TAXONOMIC STATUS OF THE SPECIES

European black pine (Pinus nigra ARNOLD) is generally considered a col lective species with many taxonomic problems. Genetic variation in 5 n atural populations of Pinus nigra (Austria, Bulgaria, Greece, Corsica, Calabria) was investigated, at the enzyme level, by using the techniq ue of starch gel electrophoresis. Isozyme patterns of 10 enzyme system s (MDH, 6PGD, MR, IDH, PGM, DIA, AAT, LAP, PGI, GDH) were studied. Ana lysis, using haploid megagametophyte tissue, demonstrated that the all ozyme variants in the above enzyme systems were coded by a total of 42 structural genes in the 16 readable loci. In one of these loci (IDH), no variants were found. The results of this study showed the followin g: a) The loci (isozymes) of DIA appeared in MR enzyme system as well. b) On the average, 70.0 % of the analyzed loci were polymorphic, whil e the number of alleles detected per locus (A/L) ranged from 1.87 (Cal abria, Greece) to 2.31 (Bulgaria) with a mean value for all studied po pulations of 2.025 allleles per locus. c) Heterozygosity ranged from 0 .180 (Corsica) to 0.257 (Bulgaria). d) 94% of the total variation of t he species was due to intrapopulation gene diversity. e) Isozymes cont ributed differently in the total variation of the species. f) Isozyme variation is a useful tool for the taxonomy of Pinus nigra, since it c an discriminate either different subspecies or different populations w ithin a given subspecies. g) The most appropriate enzyme systems for c lassification of the subspecies [ssp. Zaricio, nigra (austriaca), pall asiana] were MDH, DIA, 6PGD and AAT. h) There was a clear distinction between laricio group (Calabria, Corsica) and austriaca group (Austria , Bulgaria). i) The Greek provenance was closer to the austriaca group .