The genetic diversity and the genetic differentiation of 11 native populations of European beech from Piedmont (north-western Italy) were studied by means of the allozyme variation at 10 loci. Data obtained also contributed to the identification of the most valuable stands for the production of high quality seed. Horizontal electrophoresis on starch gel was employed to separate the variants of 7 enzyme systems: Got, G3pdh, Idh, Mdh, Mnr, 6Pgdh and Pgi. The expected heterozygosity ranged from 0.177 to 0.278 with an average of 0.232; the mean number of alleles per locus was 2.12 and 68.18% of loci were polymorphic. Only 4.3% of the total genetic diversity was due to differentiation among populations and the mean value of Nei’s genetic distance was 0.013. The sharing of one gene pool among the studied beechwoods suggests a lack of barriers to gene flow. It was possible to score a significant correlation between the frequency of the allele 6Pgdh-B1 and the altitude where the samples were collected, while the north exposure was related to a higher mean heterozygosity. Although no correlation between genotype and geographical distance could be found, the stands from the same province showed a certain degree of similarity. On the basis of the genetic distances, the very old stand of Palanfrè was clearly distinguishable from the others. Moreover, it displayed the highest level of expected heterozygosity.
Allozyme variation among European Beech (Fagus sylvatica L.) stands in Piedmont, north-western Italy
BELLETTI, Piero;LANTERI, Sergio
1996-01-01
Abstract
The genetic diversity and the genetic differentiation of 11 native populations of European beech from Piedmont (north-western Italy) were studied by means of the allozyme variation at 10 loci. Data obtained also contributed to the identification of the most valuable stands for the production of high quality seed. Horizontal electrophoresis on starch gel was employed to separate the variants of 7 enzyme systems: Got, G3pdh, Idh, Mdh, Mnr, 6Pgdh and Pgi. The expected heterozygosity ranged from 0.177 to 0.278 with an average of 0.232; the mean number of alleles per locus was 2.12 and 68.18% of loci were polymorphic. Only 4.3% of the total genetic diversity was due to differentiation among populations and the mean value of Nei’s genetic distance was 0.013. The sharing of one gene pool among the studied beechwoods suggests a lack of barriers to gene flow. It was possible to score a significant correlation between the frequency of the allele 6Pgdh-B1 and the altitude where the samples were collected, while the north exposure was related to a higher mean heterozygosity. Although no correlation between genotype and geographical distance could be found, the stands from the same province showed a certain degree of similarity. On the basis of the genetic distances, the very old stand of Palanfrè was clearly distinguishable from the others. Moreover, it displayed the highest level of expected heterozygosity.
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