GENETIC VARIABILITY AND STRUCTURE AMONG SWISS STONE PINE (PINUS CEMBRA L.) AND SCOTCH PINE (PINUS SYLVESTRIS L.) POPULATIONS IN WESTERN ALPS The genetic diversity and the genetic differentiation among 5 populations of Swiss stone pine and 5 of Scotch pine from Western Alps were studied by means of isozyme variation at fifteen loci. The two species showed similar values of mean number of alleles per locus and percentage of polymorphic loci, while expected heterozygosity for Scotch pine was higher than that for Swiss stone pine (0.332 vs 0.281). All the populations studied showed homozygotes excess: the Allevet population of P. cembra had the highest value of fixation index (0.266). Furthermore, the latter stand showed also the lowest values of allelic richness indexes. Only 2.7 and 3.5% (respectively for Swiss stone pine and Scotch pine) of the observed genetic diversity was due to differentiation among populations: therefore the populations studied share same gene pools and no barriers hamper the gene flow. The results of the study provide useful information for in situ preservation of genetic variability. Moreover, the data obtained can be also used for the identification of the most valuable stands for the production of high quality seeds.
Biodiversità e struttura genetica in popolazioni di pino cembro e pino silvestre dell'arco alpino occidentale
BELLETTI, Piero;
1999-01-01
Abstract
GENETIC VARIABILITY AND STRUCTURE AMONG SWISS STONE PINE (PINUS CEMBRA L.) AND SCOTCH PINE (PINUS SYLVESTRIS L.) POPULATIONS IN WESTERN ALPS The genetic diversity and the genetic differentiation among 5 populations of Swiss stone pine and 5 of Scotch pine from Western Alps were studied by means of isozyme variation at fifteen loci. The two species showed similar values of mean number of alleles per locus and percentage of polymorphic loci, while expected heterozygosity for Scotch pine was higher than that for Swiss stone pine (0.332 vs 0.281). All the populations studied showed homozygotes excess: the Allevet population of P. cembra had the highest value of fixation index (0.266). Furthermore, the latter stand showed also the lowest values of allelic richness indexes. Only 2.7 and 3.5% (respectively for Swiss stone pine and Scotch pine) of the observed genetic diversity was due to differentiation among populations: therefore the populations studied share same gene pools and no barriers hamper the gene flow. The results of the study provide useful information for in situ preservation of genetic variability. Moreover, the data obtained can be also used for the identification of the most valuable stands for the production of high quality seeds.
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